root/drivers/usb/gadget/function/uvc_configfs.c
// SPDX-License-Identifier: GPL-2.0
/*
 * uvc_configfs.c
 *
 * Configfs support for the uvc function.
 *
 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
 */

#include "uvc_configfs.h"

#include <linux/hex.h>
#include <linux/sort.h>
#include <linux/usb/uvc.h>
#include <linux/usb/video.h>

/* -----------------------------------------------------------------------------
 * Global Utility Structures and Macros
 */

#define UVC_ATTR(prefix, cname, aname) \
static struct configfs_attribute prefix##attr_##cname = { \
        .ca_name        = __stringify(aname),                           \
        .ca_mode        = S_IRUGO | S_IWUGO,                            \
        .ca_owner       = THIS_MODULE,                                  \
        .show           = prefix##cname##_show,                         \
        .store          = prefix##cname##_store,                        \
}

#define UVC_ATTR_RO(prefix, cname, aname) \
static struct configfs_attribute prefix##attr_##cname = { \
        .ca_name        = __stringify(aname),                           \
        .ca_mode        = S_IRUGO,                                      \
        .ca_owner       = THIS_MODULE,                                  \
        .show           = prefix##cname##_show,                         \
}

#define le8_to_cpu(x)   (x)
#define cpu_to_le8(x)   (x)

static int uvcg_config_compare_u32(const void *l, const void *r)
{
        u32 li = *(const u32 *)l;
        u32 ri = *(const u32 *)r;

        return li < ri ? -1 : li == ri ? 0 : 1;
}

static inline int __uvcg_count_item_entries(char *buf, void *priv, unsigned int size)
{
        ++*((int *)priv);
        return 0;
}

static inline int __uvcg_fill_item_entries(char *buf, void *priv, unsigned int size)
{
        unsigned int num;
        u8 **values;
        int ret;

        ret = kstrtouint(buf, 0, &num);
        if (ret)
                return ret;

        if (num != (num & GENMASK((size * 8) - 1, 0)))
                return -ERANGE;

        values = priv;
        memcpy(*values, &num, size);
        *values += size;

        return 0;
}

static int __uvcg_iter_item_entries(const char *page, size_t len,
                                    int (*fun)(char *, void *, unsigned int),
                                    void *priv, unsigned int size)
{
        /* sign, base 2 representation, newline, terminator */
        unsigned int bufsize = 1 + size * 8 + 1 + 1;
        const char *pg = page;
        int i, ret = 0;
        char *buf;

        if (!fun)
                return -EINVAL;

        buf = kzalloc(bufsize, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        while (pg - page < len) {
                i = 0;
                while (i < bufsize && (pg - page < len) &&
                       *pg != '\0' && *pg != '\n')
                        buf[i++] = *pg++;
                if (i == bufsize) {
                        ret = -EINVAL;
                        goto out_free_buf;
                }
                while ((pg - page < len) && (*pg == '\0' || *pg == '\n'))
                        ++pg;
                buf[i] = '\0';
                ret = fun(buf, priv, size);
                if (ret)
                        goto out_free_buf;
        }

out_free_buf:
        kfree(buf);
        return ret;
}

struct uvcg_config_group_type {
        struct config_item_type type;
        const char *name;
        const struct uvcg_config_group_type **children;
        int (*create_children)(struct config_group *group);
};

static void uvcg_config_item_release(struct config_item *item)
{
        struct config_group *group = to_config_group(item);

        kfree(group);
}

static const struct configfs_item_operations uvcg_config_item_ops = {
        .release        = uvcg_config_item_release,
};

static int uvcg_config_create_group(struct config_group *parent,
                                    const struct uvcg_config_group_type *type);

static int uvcg_config_create_children(struct config_group *group,
                                const struct uvcg_config_group_type *type)
{
        const struct uvcg_config_group_type **child;
        int ret;

        if (type->create_children)
                return type->create_children(group);

        for (child = type->children; child && *child; ++child) {
                ret = uvcg_config_create_group(group, *child);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int uvcg_config_create_group(struct config_group *parent,
                                    const struct uvcg_config_group_type *type)
{
        struct config_group *group;

        group = kzalloc_obj(*group);
        if (!group)
                return -ENOMEM;

        config_group_init_type_name(group, type->name, &type->type);
        configfs_add_default_group(group, parent);

        return uvcg_config_create_children(group, type);
}

static void uvcg_config_remove_children(struct config_group *group)
{
        struct config_group *child, *n;

        list_for_each_entry_safe(child, n, &group->default_groups, group_entry) {
                list_del(&child->group_entry);
                uvcg_config_remove_children(child);
                config_item_put(&child->cg_item);
        }
}

/* -----------------------------------------------------------------------------
 * control/header/<NAME>
 * control/header
 */

#define UVCG_CTRL_HDR_ATTR(cname, aname, bits, limit)                   \
static ssize_t uvcg_control_header_##cname##_show(                      \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct uvcg_control_header *ch = to_uvcg_control_header(item);  \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;\
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = ch->item.ci_parent->ci_parent->ci_parent;           \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(ch->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t                                                          \
uvcg_control_header_##cname##_store(struct config_item *item,           \
                           const char *page, size_t len)                \
{                                                                       \
        struct uvcg_control_header *ch = to_uvcg_control_header(item);  \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;\
        int ret;                                                        \
        u##bits num;                                                    \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = ch->item.ci_parent->ci_parent->ci_parent;           \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (ch->linked || opts->refcnt) {                               \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = kstrtou##bits(page, 0, &num);                             \
        if (ret)                                                        \
                goto end;                                               \
                                                                        \
        if (num > limit) {                                              \
                ret = -EINVAL;                                          \
                goto end;                                               \
        }                                                               \
        ch->desc.aname = cpu_to_le##bits(num);                          \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        mutex_unlock(su_mutex);                                         \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(uvcg_control_header_, cname, aname)

UVCG_CTRL_HDR_ATTR(bcd_uvc, bcdUVC, 16, 0xffff);

UVCG_CTRL_HDR_ATTR(dw_clock_frequency, dwClockFrequency, 32, 0x7fffffff);

#undef UVCG_CTRL_HDR_ATTR

static struct configfs_attribute *uvcg_control_header_attrs[] = {
        &uvcg_control_header_attr_bcd_uvc,
        &uvcg_control_header_attr_dw_clock_frequency,
        NULL,
};

static const struct config_item_type uvcg_control_header_type = {
        .ct_item_ops    = &uvcg_config_item_ops,
        .ct_attrs       = uvcg_control_header_attrs,
        .ct_owner       = THIS_MODULE,
};

static struct config_item *uvcg_control_header_make(struct config_group *group,
                                                    const char *name)
{
        struct uvcg_control_header *h;

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        h->desc.bLength                 = UVC_DT_HEADER_SIZE(1);
        h->desc.bDescriptorType         = USB_DT_CS_INTERFACE;
        h->desc.bDescriptorSubType      = UVC_VC_HEADER;
        h->desc.bcdUVC                  = cpu_to_le16(0x0110);
        h->desc.dwClockFrequency        = cpu_to_le32(48000000);

        config_item_init_type_name(&h->item, name, &uvcg_control_header_type);

        return &h->item;
}

static const struct configfs_group_operations uvcg_control_header_grp_ops = {
        .make_item              = uvcg_control_header_make,
};

static const struct uvcg_config_group_type uvcg_control_header_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_control_header_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "header",
};

/* -----------------------------------------------------------------------------
 * control/processing/default
 */

#define UVCG_DEFAULT_PROCESSING_ATTR(cname, aname, bits)                \
static ssize_t uvcg_default_processing_##cname##_show(                  \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct config_group *group = to_config_group(item);             \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        struct uvc_processing_unit_descriptor *pd;                      \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;     \
        opts = to_f_uvc_opts(opts_item);                                \
        pd = &opts->uvc_processing;                                     \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(pd->aname));   \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_default_processing_, cname, aname)

UVCG_DEFAULT_PROCESSING_ATTR(b_unit_id, bUnitID, 8);
UVCG_DEFAULT_PROCESSING_ATTR(b_source_id, bSourceID, 8);
UVCG_DEFAULT_PROCESSING_ATTR(w_max_multiplier, wMaxMultiplier, 16);
UVCG_DEFAULT_PROCESSING_ATTR(i_processing, iProcessing, 8);

#undef UVCG_DEFAULT_PROCESSING_ATTR

static ssize_t uvcg_default_processing_bm_controls_store(
        struct config_item *item, const char *page, size_t len)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_processing_unit_descriptor *pd;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        u8 *bm_controls, *tmp;
        unsigned int i;
        int ret, n = 0;

        mutex_lock(su_mutex);

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);
        pd = &opts->uvc_processing;

        mutex_lock(&opts->lock);
        if (opts->refcnt) {
                ret = -EBUSY;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
                                       sizeof(u8));
        if (ret)
                goto unlock;

        if (n > pd->bControlSize) {
                ret = -EINVAL;
                goto unlock;
        }

        tmp = bm_controls = kcalloc(n, sizeof(u8), GFP_KERNEL);
        if (!bm_controls) {
                ret = -ENOMEM;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &tmp,
                                       sizeof(u8));
        if (ret)
                goto free_mem;

        for (i = 0; i < n; i++)
                pd->bmControls[i] = bm_controls[i];

        ret = len;

free_mem:
        kfree(bm_controls);
unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

static ssize_t uvcg_default_processing_bm_controls_show(
        struct config_item *item, char *page)
{
        struct config_group *group = to_config_group(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_processing_unit_descriptor *pd;
        int result, i;
        char *pg = page;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);
        pd = &opts->uvc_processing;

        mutex_lock(&opts->lock);
        for (result = 0, i = 0; i < pd->bControlSize; ++i) {
                result += sprintf(pg, "%u\n", pd->bmControls[i]);
                pg = page + result;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return result;
}

UVC_ATTR(uvcg_default_processing_, bm_controls, bmControls);

static struct configfs_attribute *uvcg_default_processing_attrs[] = {
        &uvcg_default_processing_attr_b_unit_id,
        &uvcg_default_processing_attr_b_source_id,
        &uvcg_default_processing_attr_w_max_multiplier,
        &uvcg_default_processing_attr_bm_controls,
        &uvcg_default_processing_attr_i_processing,
        NULL,
};

static const struct uvcg_config_group_type uvcg_default_processing_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_attrs       = uvcg_default_processing_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "default",
};

/* -----------------------------------------------------------------------------
 * control/processing
 */

static const struct uvcg_config_group_type uvcg_processing_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "processing",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_default_processing_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * control/terminal/camera/default
 */

#define UVCG_DEFAULT_CAMERA_ATTR(cname, aname, bits)                    \
static ssize_t uvcg_default_camera_##cname##_show(                      \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct config_group *group = to_config_group(item);             \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        struct uvc_camera_terminal_descriptor *cd;                      \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent->    \
                        ci_parent;                                      \
        opts = to_f_uvc_opts(opts_item);                                \
        cd = &opts->uvc_camera_terminal;                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(cd->aname));   \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
                                                                        \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_default_camera_, cname, aname)

UVCG_DEFAULT_CAMERA_ATTR(b_terminal_id, bTerminalID, 8);
UVCG_DEFAULT_CAMERA_ATTR(w_terminal_type, wTerminalType, 16);
UVCG_DEFAULT_CAMERA_ATTR(b_assoc_terminal, bAssocTerminal, 8);
UVCG_DEFAULT_CAMERA_ATTR(i_terminal, iTerminal, 8);
UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_min, wObjectiveFocalLengthMin,
                         16);
UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_max, wObjectiveFocalLengthMax,
                         16);
UVCG_DEFAULT_CAMERA_ATTR(w_ocular_focal_length, wOcularFocalLength,
                         16);

#undef UVCG_DEFAULT_CAMERA_ATTR

static ssize_t uvcg_default_camera_bm_controls_store(
        struct config_item *item, const char *page, size_t len)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_camera_terminal_descriptor *cd;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        u8 *bm_controls, *tmp;
        unsigned int i;
        int ret, n = 0;

        mutex_lock(su_mutex);

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent->
                        ci_parent;
        opts = to_f_uvc_opts(opts_item);
        cd = &opts->uvc_camera_terminal;

        mutex_lock(&opts->lock);
        if (opts->refcnt) {
                ret = -EBUSY;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
                                       sizeof(u8));
        if (ret)
                goto unlock;

        if (n > cd->bControlSize) {
                ret = -EINVAL;
                goto unlock;
        }

        tmp = bm_controls = kcalloc(n, sizeof(u8), GFP_KERNEL);
        if (!bm_controls) {
                ret = -ENOMEM;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &tmp,
                                       sizeof(u8));
        if (ret)
                goto free_mem;

        for (i = 0; i < n; i++)
                cd->bmControls[i] = bm_controls[i];

        ret = len;

free_mem:
        kfree(bm_controls);
unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

static ssize_t uvcg_default_camera_bm_controls_show(
        struct config_item *item, char *page)
{
        struct config_group *group = to_config_group(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_camera_terminal_descriptor *cd;
        int result, i;
        char *pg = page;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent->
                        ci_parent;
        opts = to_f_uvc_opts(opts_item);
        cd = &opts->uvc_camera_terminal;

        mutex_lock(&opts->lock);
        for (result = 0, i = 0; i < cd->bControlSize; ++i) {
                result += sprintf(pg, "%u\n", cd->bmControls[i]);
                pg = page + result;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);
        return result;
}

UVC_ATTR(uvcg_default_camera_, bm_controls, bmControls);

static struct configfs_attribute *uvcg_default_camera_attrs[] = {
        &uvcg_default_camera_attr_b_terminal_id,
        &uvcg_default_camera_attr_w_terminal_type,
        &uvcg_default_camera_attr_b_assoc_terminal,
        &uvcg_default_camera_attr_i_terminal,
        &uvcg_default_camera_attr_w_objective_focal_length_min,
        &uvcg_default_camera_attr_w_objective_focal_length_max,
        &uvcg_default_camera_attr_w_ocular_focal_length,
        &uvcg_default_camera_attr_bm_controls,
        NULL,
};

static const struct uvcg_config_group_type uvcg_default_camera_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_attrs       = uvcg_default_camera_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "default",
};

/* -----------------------------------------------------------------------------
 * control/terminal/camera
 */

static const struct uvcg_config_group_type uvcg_camera_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "camera",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_default_camera_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * control/terminal/output/default
 */

#define UVCG_DEFAULT_OUTPUT_ATTR(cname, aname, bits)                    \
static ssize_t uvcg_default_output_##cname##_show(                      \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct config_group *group = to_config_group(item);             \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        struct uvc_output_terminal_descriptor *cd;                      \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = group->cg_item.ci_parent->ci_parent->               \
                        ci_parent->ci_parent;                           \
        opts = to_f_uvc_opts(opts_item);                                \
        cd = &opts->uvc_output_terminal;                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(cd->aname));   \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
                                                                        \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_default_output_, cname, aname)

UVCG_DEFAULT_OUTPUT_ATTR(b_terminal_id, bTerminalID, 8);
UVCG_DEFAULT_OUTPUT_ATTR(w_terminal_type, wTerminalType, 16);
UVCG_DEFAULT_OUTPUT_ATTR(b_assoc_terminal, bAssocTerminal, 8);
UVCG_DEFAULT_OUTPUT_ATTR(i_terminal, iTerminal, 8);

#undef UVCG_DEFAULT_OUTPUT_ATTR

static ssize_t uvcg_default_output_b_source_id_show(struct config_item *item,
                                                    char *page)
{
        struct config_group *group = to_config_group(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_output_terminal_descriptor *cd;
        int result;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = group->cg_item.ci_parent->ci_parent->
                        ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);
        cd = &opts->uvc_output_terminal;

        mutex_lock(&opts->lock);
        result = sprintf(page, "%u\n", le8_to_cpu(cd->bSourceID));
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return result;
}

static ssize_t uvcg_default_output_b_source_id_store(struct config_item *item,
                                                     const char *page, size_t len)
{
        struct config_group *group = to_config_group(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvc_output_terminal_descriptor *cd;
        int result;
        u8 num;

        result = kstrtou8(page, 0, &num);
        if (result)
                return result;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = group->cg_item.ci_parent->ci_parent->
                        ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);
        cd = &opts->uvc_output_terminal;

        mutex_lock(&opts->lock);
        cd->bSourceID = num;
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return len;
}
UVC_ATTR(uvcg_default_output_, b_source_id, bSourceID);

static struct configfs_attribute *uvcg_default_output_attrs[] = {
        &uvcg_default_output_attr_b_terminal_id,
        &uvcg_default_output_attr_w_terminal_type,
        &uvcg_default_output_attr_b_assoc_terminal,
        &uvcg_default_output_attr_b_source_id,
        &uvcg_default_output_attr_i_terminal,
        NULL,
};

static const struct uvcg_config_group_type uvcg_default_output_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_attrs       = uvcg_default_output_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "default",
};

/* -----------------------------------------------------------------------------
 * control/terminal/output
 */

static const struct uvcg_config_group_type uvcg_output_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "output",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_default_output_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * control/terminal
 */

static const struct uvcg_config_group_type uvcg_terminal_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "terminal",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_camera_grp_type,
                &uvcg_output_grp_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * control/extensions
 */

#define UVCG_EXTENSION_ATTR(cname, aname, ro...)                        \
static ssize_t uvcg_extension_##cname##_show(struct config_item *item,  \
                                             char *page)                \
{                                                                       \
        struct config_group *group = to_config_group(item->ci_parent);  \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        struct uvcg_extension *xu = to_uvcg_extension(item);            \
        struct config_item *opts_item;                                  \
        struct f_uvc_opts *opts;                                        \
        int ret;                                                        \
                                                                        \
        mutex_lock(su_mutex);                                           \
                                                                        \
        opts_item = item->ci_parent->ci_parent->ci_parent;              \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        ret = sprintf(page, "%u\n", xu->desc.aname);                    \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
                                                                        \
        return ret;                                                     \
}                                                                       \
UVC_ATTR##ro(uvcg_extension_, cname, aname)

UVCG_EXTENSION_ATTR(b_length, bLength, _RO);
UVCG_EXTENSION_ATTR(b_unit_id, bUnitID, _RO);
UVCG_EXTENSION_ATTR(i_extension, iExtension, _RO);

static ssize_t uvcg_extension_b_num_controls_store(struct config_item *item,
                                                   const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        int ret;
        u8 num;

        ret = kstrtou8(page, 0, &num);
        if (ret)
                return ret;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        xu->desc.bNumControls = num;
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return len;
}
UVCG_EXTENSION_ATTR(b_num_controls, bNumControls);

/*
 * In addition to storing bNrInPins, this function needs to realloc the
 * memory for the baSourceID array and additionally expand bLength.
 */
static ssize_t uvcg_extension_b_nr_in_pins_store(struct config_item *item,
                                                 const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        void *tmp_buf;
        int ret;
        u8 num;

        ret = kstrtou8(page, 0, &num);
        if (ret)
                return ret;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        if (num == xu->desc.bNrInPins) {
                ret = len;
                goto unlock;
        }

        tmp_buf = krealloc_array(xu->desc.baSourceID, num, sizeof(u8),
                                 GFP_KERNEL | __GFP_ZERO);
        if (!tmp_buf) {
                ret = -ENOMEM;
                goto unlock;
        }

        xu->desc.baSourceID = tmp_buf;
        xu->desc.bNrInPins = num;
        xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
                                                      xu->desc.bControlSize);

        ret = len;

unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}
UVCG_EXTENSION_ATTR(b_nr_in_pins, bNrInPins);

/*
 * In addition to storing bControlSize, this function needs to realloc the
 * memory for the bmControls array and additionally expand bLength.
 */
static ssize_t uvcg_extension_b_control_size_store(struct config_item *item,
                                                   const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        void *tmp_buf;
        int ret;
        u8 num;

        ret = kstrtou8(page, 0, &num);
        if (ret)
                return ret;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        if (num == xu->desc.bControlSize) {
                ret = len;
                goto unlock;
        }

        tmp_buf = krealloc_array(xu->desc.bmControls, num, sizeof(u8),
                                 GFP_KERNEL | __GFP_ZERO);
        if (!tmp_buf) {
                ret = -ENOMEM;
                goto unlock;
        }

        xu->desc.bmControls = tmp_buf;
        xu->desc.bControlSize = num;
        xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
                                                      xu->desc.bControlSize);

        ret = len;

unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

UVCG_EXTENSION_ATTR(b_control_size, bControlSize);

static ssize_t uvcg_extension_guid_extension_code_show(struct config_item *item,
                                                       char *page)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        memcpy(page, xu->desc.guidExtensionCode, sizeof(xu->desc.guidExtensionCode));
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return sizeof(xu->desc.guidExtensionCode);
}

static ssize_t uvcg_extension_guid_extension_code_store(struct config_item *item,
                                                        const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        int ret;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        memcpy(xu->desc.guidExtensionCode, page,
               min(sizeof(xu->desc.guidExtensionCode), len));
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        ret = sizeof(xu->desc.guidExtensionCode);

        return ret;
}

UVC_ATTR(uvcg_extension_, guid_extension_code, guidExtensionCode);

static ssize_t uvcg_extension_ba_source_id_show(struct config_item *item,
                                                char *page)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        char *pg = page;
        int ret, i;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        for (ret = 0, i = 0; i < xu->desc.bNrInPins; ++i) {
                ret += sprintf(pg, "%u\n", xu->desc.baSourceID[i]);
                pg = page + ret;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return ret;
}

static ssize_t uvcg_extension_ba_source_id_store(struct config_item *item,
                                                 const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        u8 *source_ids, *iter;
        int ret, n = 0;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
                                       sizeof(u8));
        if (ret)
                goto unlock;

        iter = source_ids = kcalloc(n, sizeof(u8), GFP_KERNEL);
        if (!source_ids) {
                ret = -ENOMEM;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &iter,
                                       sizeof(u8));
        if (ret) {
                kfree(source_ids);
                goto unlock;
        }

        kfree(xu->desc.baSourceID);
        xu->desc.baSourceID = source_ids;
        xu->desc.bNrInPins = n;
        xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
                                                      xu->desc.bControlSize);

        ret = len;

unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}
UVC_ATTR(uvcg_extension_, ba_source_id, baSourceID);

static ssize_t uvcg_extension_bm_controls_show(struct config_item *item,
                                               char *page)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        char *pg = page;
        int ret, i;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        for (ret = 0, i = 0; i < xu->desc.bControlSize; ++i) {
                ret += sprintf(pg, "0x%02x\n", xu->desc.bmControls[i]);
                pg = page + ret;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return ret;
}

static ssize_t uvcg_extension_bm_controls_store(struct config_item *item,
                                                const char *page, size_t len)
{
        struct config_group *group = to_config_group(item->ci_parent);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        u8 *bm_controls, *iter;
        int ret, n = 0;

        mutex_lock(su_mutex);

        opts_item = item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n,
                                       sizeof(u8));
        if (ret)
                goto unlock;

        iter = bm_controls = kcalloc(n, sizeof(u8), GFP_KERNEL);
        if (!bm_controls) {
                ret = -ENOMEM;
                goto unlock;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &iter,
                                       sizeof(u8));
        if (ret) {
                kfree(bm_controls);
                goto unlock;
        }

        kfree(xu->desc.bmControls);
        xu->desc.bmControls = bm_controls;
        xu->desc.bControlSize = n;
        xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(xu->desc.bNrInPins,
                                                      xu->desc.bControlSize);

        ret = len;

unlock:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

UVC_ATTR(uvcg_extension_, bm_controls, bmControls);

static struct configfs_attribute *uvcg_extension_attrs[] = {
        &uvcg_extension_attr_b_length,
        &uvcg_extension_attr_b_unit_id,
        &uvcg_extension_attr_b_num_controls,
        &uvcg_extension_attr_b_nr_in_pins,
        &uvcg_extension_attr_b_control_size,
        &uvcg_extension_attr_guid_extension_code,
        &uvcg_extension_attr_ba_source_id,
        &uvcg_extension_attr_bm_controls,
        &uvcg_extension_attr_i_extension,
        NULL,
};

static void uvcg_extension_release(struct config_item *item)
{
        struct uvcg_extension *xu = container_of(item, struct uvcg_extension, item);

        kfree(xu);
}

static int uvcg_extension_allow_link(struct config_item *src, struct config_item *tgt)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(src);
        struct config_item *gadget_item;
        struct gadget_string *string;
        struct config_item *strings;
        int ret = 0;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        /* Validate that the target of the link is an entry in strings/<langid> */
        gadget_item = src->ci_parent->ci_parent->ci_parent->ci_parent->ci_parent;
        strings = config_group_find_item(to_config_group(gadget_item), "strings");
        if (!strings || tgt->ci_parent->ci_parent != strings) {
                ret = -EINVAL;
                goto put_strings;
        }

        string = to_gadget_string(tgt);
        xu->string_descriptor_index = string->usb_string.id;

put_strings:
        config_item_put(strings);
        mutex_unlock(su_mutex);

        return ret;
}

static void uvcg_extension_drop_link(struct config_item *src, struct config_item *tgt)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvcg_extension *xu = to_uvcg_extension(src);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = src->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        xu->string_descriptor_index = 0;

        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);
}

static const struct configfs_item_operations uvcg_extension_item_ops = {
        .release        = uvcg_extension_release,
        .allow_link     = uvcg_extension_allow_link,
        .drop_link      = uvcg_extension_drop_link,
};

static const struct config_item_type uvcg_extension_type = {
        .ct_item_ops    = &uvcg_extension_item_ops,
        .ct_attrs       = uvcg_extension_attrs,
        .ct_owner       = THIS_MODULE,
};

static void uvcg_extension_drop(struct config_group *group, struct config_item *item)
{
        struct uvcg_extension *xu = container_of(item, struct uvcg_extension, item);
        struct config_item *opts_item;
        struct f_uvc_opts *opts;

        opts_item = group->cg_item.ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        config_item_put(item);
        list_del(&xu->list);
        kfree(xu->desc.baSourceID);
        kfree(xu->desc.bmControls);

        mutex_unlock(&opts->lock);
}

static struct config_item *uvcg_extension_make(struct config_group *group, const char *name)
{
        struct config_item *opts_item;
        struct uvcg_extension *xu;
        struct f_uvc_opts *opts;

        opts_item = group->cg_item.ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        xu = kzalloc_obj(*xu);
        if (!xu)
                return ERR_PTR(-ENOMEM);

        xu->desc.bLength = UVC_DT_EXTENSION_UNIT_SIZE(0, 0);
        xu->desc.bDescriptorType = USB_DT_CS_INTERFACE;
        xu->desc.bDescriptorSubType = UVC_VC_EXTENSION_UNIT;
        xu->desc.bNumControls = 0;
        xu->desc.bNrInPins = 0;
        xu->desc.baSourceID = NULL;
        xu->desc.bControlSize = 0;
        xu->desc.bmControls = NULL;

        mutex_lock(&opts->lock);

        xu->desc.bUnitID = ++opts->last_unit_id;

        config_item_init_type_name(&xu->item, name, &uvcg_extension_type);
        list_add_tail(&xu->list, &opts->extension_units);

        mutex_unlock(&opts->lock);

        return &xu->item;
}

static const struct configfs_group_operations uvcg_extensions_grp_ops = {
        .make_item      = uvcg_extension_make,
        .drop_item      = uvcg_extension_drop,
};

static const struct uvcg_config_group_type uvcg_extensions_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_extensions_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "extensions",
};

/* -----------------------------------------------------------------------------
 * control/class/{fs|ss}
 */

struct uvcg_control_class_group {
        struct config_group group;
        const char *name;
};

static inline struct uvc_descriptor_header
**uvcg_get_ctl_class_arr(struct config_item *i, struct f_uvc_opts *o)
{
        struct uvcg_control_class_group *group =
                container_of(i, struct uvcg_control_class_group,
                             group.cg_item);

        if (!strcmp(group->name, "fs"))
                return o->uvc_fs_control_cls;

        if (!strcmp(group->name, "ss"))
                return o->uvc_ss_control_cls;

        return NULL;
}

static int uvcg_control_class_allow_link(struct config_item *src,
                                         struct config_item *target)
{
        struct config_item *control, *header;
        struct f_uvc_opts *opts;
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvc_descriptor_header **class_array;
        struct uvcg_control_header *target_hdr;
        int ret = -EINVAL;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        control = src->ci_parent->ci_parent;
        header = config_group_find_item(to_config_group(control), "header");
        if (!header || target->ci_parent != header)
                goto out;

        opts = to_f_uvc_opts(control->ci_parent);

        mutex_lock(&opts->lock);

        class_array = uvcg_get_ctl_class_arr(src, opts);
        if (!class_array)
                goto unlock;
        if (opts->refcnt || class_array[0]) {
                ret = -EBUSY;
                goto unlock;
        }

        target_hdr = to_uvcg_control_header(target);
        ++target_hdr->linked;
        class_array[0] = (struct uvc_descriptor_header *)&target_hdr->desc;
        ret = 0;

unlock:
        mutex_unlock(&opts->lock);
out:
        config_item_put(header);
        mutex_unlock(su_mutex);
        return ret;
}

static void uvcg_control_class_drop_link(struct config_item *src,
                                        struct config_item *target)
{
        struct config_item *control, *header;
        struct f_uvc_opts *opts;
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvc_descriptor_header **class_array;
        struct uvcg_control_header *target_hdr;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        control = src->ci_parent->ci_parent;
        header = config_group_find_item(to_config_group(control), "header");
        if (!header || target->ci_parent != header)
                goto out;

        opts = to_f_uvc_opts(control->ci_parent);

        mutex_lock(&opts->lock);

        class_array = uvcg_get_ctl_class_arr(src, opts);
        if (!class_array || opts->refcnt)
                goto unlock;

        target_hdr = to_uvcg_control_header(target);
        --target_hdr->linked;
        class_array[0] = NULL;

unlock:
        mutex_unlock(&opts->lock);
out:
        config_item_put(header);
        mutex_unlock(su_mutex);
}

static const struct configfs_item_operations uvcg_control_class_item_ops = {
        .release        = uvcg_config_item_release,
        .allow_link     = uvcg_control_class_allow_link,
        .drop_link      = uvcg_control_class_drop_link,
};

static const struct config_item_type uvcg_control_class_type = {
        .ct_item_ops    = &uvcg_control_class_item_ops,
        .ct_owner       = THIS_MODULE,
};

/* -----------------------------------------------------------------------------
 * control/class
 */

static int uvcg_control_class_create_children(struct config_group *parent)
{
        static const char * const names[] = { "fs", "ss" };
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(names); ++i) {
                struct uvcg_control_class_group *group;

                group = kzalloc_obj(*group);
                if (!group)
                        return -ENOMEM;

                group->name = names[i];

                config_group_init_type_name(&group->group, group->name,
                                            &uvcg_control_class_type);
                configfs_add_default_group(&group->group, parent);
        }

        return 0;
}

static const struct uvcg_config_group_type uvcg_control_class_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "class",
        .create_children = uvcg_control_class_create_children,
};

/* -----------------------------------------------------------------------------
 * control
 */

static ssize_t uvcg_default_control_b_interface_number_show(
        struct config_item *item, char *page)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        int result = 0;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = item->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        result += sprintf(page, "%u\n", opts->control_interface);
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return result;
}

UVC_ATTR_RO(uvcg_default_control_, b_interface_number, bInterfaceNumber);

static ssize_t uvcg_default_control_enable_interrupt_ep_show(
        struct config_item *item, char *page)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        int result = 0;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = item->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        result += sprintf(page, "%u\n", opts->enable_interrupt_ep);
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return result;
}

static ssize_t uvcg_default_control_enable_interrupt_ep_store(
        struct config_item *item, const char *page, size_t len)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        ssize_t ret;
        u8 num;

        ret = kstrtou8(page, 0, &num);
        if (ret)
                return ret;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = item->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        opts->enable_interrupt_ep = num;
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return len;
}
UVC_ATTR(uvcg_default_control_, enable_interrupt_ep, enable_interrupt_ep);

static struct configfs_attribute *uvcg_default_control_attrs[] = {
        &uvcg_default_control_attr_b_interface_number,
        &uvcg_default_control_attr_enable_interrupt_ep,
        NULL,
};

static const struct uvcg_config_group_type uvcg_control_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_attrs       = uvcg_default_control_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "control",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_control_header_grp_type,
                &uvcg_processing_grp_type,
                &uvcg_terminal_grp_type,
                &uvcg_control_class_grp_type,
                &uvcg_extensions_grp_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * streaming/uncompressed
 * streaming/mjpeg
 * streaming/framebased
 */

static const char * const uvcg_format_names[] = {
        "uncompressed",
        "mjpeg",
        "framebased",
};

static struct uvcg_color_matching *
uvcg_format_get_default_color_match(struct config_item *streaming)
{
        struct config_item *color_matching_item, *cm_default;
        struct uvcg_color_matching *color_match;

        color_matching_item = config_group_find_item(to_config_group(streaming),
                                                     "color_matching");
        if (!color_matching_item)
                return NULL;

        cm_default = config_group_find_item(to_config_group(color_matching_item),
                                            "default");
        config_item_put(color_matching_item);
        if (!cm_default)
                return NULL;

        color_match = to_uvcg_color_matching(to_config_group(cm_default));
        config_item_put(cm_default);

        return color_match;
}

static int uvcg_format_allow_link(struct config_item *src, struct config_item *tgt)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvcg_color_matching *color_matching_desc;
        struct config_item *streaming, *color_matching;
        struct uvcg_format *fmt;
        int ret = 0;

        mutex_lock(su_mutex);

        streaming = src->ci_parent->ci_parent;
        color_matching = config_group_find_item(to_config_group(streaming), "color_matching");
        if (!color_matching || color_matching != tgt->ci_parent) {
                ret = -EINVAL;
                goto out_put_cm;
        }

        fmt = to_uvcg_format(src);

        /*
         * There's always a color matching descriptor associated with the format
         * but without a symlink it should only ever be the default one. If it's
         * not the default, there's already a symlink and we should bail out.
         */
        color_matching_desc = uvcg_format_get_default_color_match(streaming);
        if (fmt->color_matching != color_matching_desc) {
                ret = -EBUSY;
                goto out_put_cm;
        }

        color_matching_desc->refcnt--;

        color_matching_desc = to_uvcg_color_matching(to_config_group(tgt));
        fmt->color_matching = color_matching_desc;
        color_matching_desc->refcnt++;

out_put_cm:
        config_item_put(color_matching);
        mutex_unlock(su_mutex);

        return ret;
}

static void uvcg_format_drop_link(struct config_item *src, struct config_item *tgt)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvcg_color_matching *color_matching_desc;
        struct config_item *streaming;
        struct uvcg_format *fmt;

        mutex_lock(su_mutex);

        color_matching_desc = to_uvcg_color_matching(to_config_group(tgt));
        color_matching_desc->refcnt--;

        streaming = src->ci_parent->ci_parent;
        color_matching_desc = uvcg_format_get_default_color_match(streaming);

        fmt = to_uvcg_format(src);
        fmt->color_matching = color_matching_desc;
        color_matching_desc->refcnt++;

        mutex_unlock(su_mutex);
}

static const struct configfs_item_operations uvcg_format_item_operations = {
        .release        = uvcg_config_item_release,
        .allow_link     = uvcg_format_allow_link,
        .drop_link      = uvcg_format_drop_link,
};

static ssize_t uvcg_format_bma_controls_show(struct uvcg_format *f, char *page)
{
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &f->group.cg_subsys->su_mutex;
        int result, i;
        char *pg = page;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = f->group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        result = sprintf(pg, "0x");
        pg += result;
        for (i = 0; i < UVCG_STREAMING_CONTROL_SIZE; ++i) {
                result += sprintf(pg, "%x\n", f->bmaControls[i]);
                pg = page + result;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);
        return result;
}

static ssize_t uvcg_format_bma_controls_store(struct uvcg_format *ch,
                                              const char *page, size_t len)
{
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &ch->group.cg_subsys->su_mutex;
        int ret = -EINVAL;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        if (ch->linked || opts->refcnt) {
                ret = -EBUSY;
                goto end;
        }

        if (len < 4 || *page != '0' ||
            (*(page + 1) != 'x' && *(page + 1) != 'X'))
                goto end;
        ret = hex2bin(ch->bmaControls, page + 2, 1);
        if (ret < 0)
                goto end;
        ret = len;
end:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

/* -----------------------------------------------------------------------------
 * streaming/header/<NAME>
 * streaming/header
 */

static void uvcg_format_set_indices(struct config_group *fmt);

static int uvcg_streaming_header_allow_link(struct config_item *src,
                                            struct config_item *target)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        struct uvcg_streaming_header *src_hdr;
        struct uvcg_format *target_fmt = NULL;
        struct uvcg_format_ptr *format_ptr;
        int i, ret = -EINVAL;

        src_hdr = to_uvcg_streaming_header(src);
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = src->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);

        if (src_hdr->linked) {
                ret = -EBUSY;
                goto out;
        }

        /*
         * Linking is only allowed to direct children of the format nodes
         * (streaming/uncompressed or streaming/mjpeg nodes). First check that
         * the grand-parent of the target matches the grand-parent of the source
         * (the streaming node), and then verify that the target parent is a
         * format node.
         */
        if (src->ci_parent->ci_parent != target->ci_parent->ci_parent)
                goto out;

        for (i = 0; i < ARRAY_SIZE(uvcg_format_names); ++i) {
                if (!strcmp(target->ci_parent->ci_name, uvcg_format_names[i]))
                        break;
        }

        if (i == ARRAY_SIZE(uvcg_format_names))
                goto out;

        target_fmt = container_of(to_config_group(target), struct uvcg_format,
                                  group);

        if (!target_fmt)
                goto out;

        uvcg_format_set_indices(to_config_group(target));

        format_ptr = kzalloc_obj(*format_ptr);
        if (!format_ptr) {
                ret = -ENOMEM;
                goto out;
        }
        ret = 0;
        format_ptr->fmt = target_fmt;
        list_add_tail(&format_ptr->entry, &src_hdr->formats);
        ++src_hdr->num_fmt;
        ++target_fmt->linked;

out:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

static void uvcg_streaming_header_drop_link(struct config_item *src,
                                           struct config_item *target)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        struct uvcg_streaming_header *src_hdr;
        struct uvcg_format *target_fmt = NULL;
        struct uvcg_format_ptr *format_ptr, *tmp;

        src_hdr = to_uvcg_streaming_header(src);
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = src->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        target_fmt = container_of(to_config_group(target), struct uvcg_format,
                                  group);

        if (!target_fmt)
                goto out;

        list_for_each_entry_safe(format_ptr, tmp, &src_hdr->formats, entry)
                if (format_ptr->fmt == target_fmt) {
                        list_del(&format_ptr->entry);
                        kfree(format_ptr);
                        --src_hdr->num_fmt;
                        break;
                }

        --target_fmt->linked;

out:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
}

static const struct configfs_item_operations uvcg_streaming_header_item_ops = {
        .release        = uvcg_config_item_release,
        .allow_link     = uvcg_streaming_header_allow_link,
        .drop_link      = uvcg_streaming_header_drop_link,
};

#define UVCG_STREAMING_HEADER_ATTR(cname, aname, bits)                  \
static ssize_t uvcg_streaming_header_##cname##_show(                    \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct uvcg_streaming_header *sh = to_uvcg_streaming_header(item); \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &sh->item.ci_group->cg_subsys->su_mutex;\
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = sh->item.ci_parent->ci_parent->ci_parent;           \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(sh->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_streaming_header_, cname, aname)

UVCG_STREAMING_HEADER_ATTR(bm_info, bmInfo, 8);
UVCG_STREAMING_HEADER_ATTR(b_terminal_link, bTerminalLink, 8);
UVCG_STREAMING_HEADER_ATTR(b_still_capture_method, bStillCaptureMethod, 8);
UVCG_STREAMING_HEADER_ATTR(b_trigger_support, bTriggerSupport, 8);
UVCG_STREAMING_HEADER_ATTR(b_trigger_usage, bTriggerUsage, 8);

#undef UVCG_STREAMING_HEADER_ATTR

static struct configfs_attribute *uvcg_streaming_header_attrs[] = {
        &uvcg_streaming_header_attr_bm_info,
        &uvcg_streaming_header_attr_b_terminal_link,
        &uvcg_streaming_header_attr_b_still_capture_method,
        &uvcg_streaming_header_attr_b_trigger_support,
        &uvcg_streaming_header_attr_b_trigger_usage,
        NULL,
};

static const struct config_item_type uvcg_streaming_header_type = {
        .ct_item_ops    = &uvcg_streaming_header_item_ops,
        .ct_attrs       = uvcg_streaming_header_attrs,
        .ct_owner       = THIS_MODULE,
};

static struct config_item
*uvcg_streaming_header_make(struct config_group *group, const char *name)
{
        struct uvcg_streaming_header *h;

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&h->formats);
        h->desc.bDescriptorType         = USB_DT_CS_INTERFACE;
        h->desc.bDescriptorSubType      = UVC_VS_INPUT_HEADER;
        h->desc.bTerminalLink           = 3;
        h->desc.bControlSize            = UVCG_STREAMING_CONTROL_SIZE;

        config_item_init_type_name(&h->item, name, &uvcg_streaming_header_type);

        return &h->item;
}

static const struct configfs_group_operations uvcg_streaming_header_grp_ops = {
        .make_item              = uvcg_streaming_header_make,
};

static const struct uvcg_config_group_type uvcg_streaming_header_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_streaming_header_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "header",
};

/* -----------------------------------------------------------------------------
 * streaming/<mode>/<format>/<NAME>
 */

#define UVCG_FRAME_ATTR(cname, aname, bits) \
static ssize_t uvcg_frame_##cname##_show(struct config_item *item, char *page)\
{                                                                       \
        struct uvcg_frame *f = to_uvcg_frame(item);                     \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;\
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = f->item.ci_parent->ci_parent->ci_parent->ci_parent; \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", f->frame.cname);                 \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t  uvcg_frame_##cname##_store(struct config_item *item,    \
                                           const char *page, size_t len)\
{                                                                       \
        struct uvcg_frame *f = to_uvcg_frame(item);                     \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct uvcg_format *fmt;                                        \
        struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;\
        typeof(f->frame.cname) num;                                     \
        int ret;                                                        \
                                                                        \
        ret = kstrtou##bits(page, 0, &num);                             \
        if (ret)                                                        \
                return ret;                                             \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = f->item.ci_parent->ci_parent->ci_parent->ci_parent; \
        opts = to_f_uvc_opts(opts_item);                                \
        fmt = to_uvcg_format(f->item.ci_parent);                        \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (fmt->linked || opts->refcnt) {                              \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        f->frame.cname = num;                                           \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        mutex_unlock(su_mutex);                                         \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(uvcg_frame_, cname, aname);

static ssize_t uvcg_frame_b_frame_index_show(struct config_item *item,
                                             char *page)
{
        struct uvcg_frame *f = to_uvcg_frame(item);
        struct uvcg_format *fmt;
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct config_item *fmt_item;
        struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;
        int result;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        fmt_item = f->item.ci_parent;
        fmt = to_uvcg_format(fmt_item);

        if (!fmt->linked) {
                result = -EBUSY;
                goto out;
        }

        opts_item = fmt_item->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        result = sprintf(page, "%u\n", f->frame.b_frame_index);
        mutex_unlock(&opts->lock);

out:
        mutex_unlock(su_mutex);
        return result;
}

UVC_ATTR_RO(uvcg_frame_, b_frame_index, bFrameIndex);

UVCG_FRAME_ATTR(bm_capabilities, bmCapabilities, 8);
UVCG_FRAME_ATTR(w_width, wWidth, 16);
UVCG_FRAME_ATTR(w_height, wHeight, 16);
UVCG_FRAME_ATTR(dw_min_bit_rate, dwMinBitRate, 32);
UVCG_FRAME_ATTR(dw_max_bit_rate, dwMaxBitRate, 32);
UVCG_FRAME_ATTR(dw_max_video_frame_buffer_size, dwMaxVideoFrameBufferSize, 32);
UVCG_FRAME_ATTR(dw_default_frame_interval, dwDefaultFrameInterval, 32);
UVCG_FRAME_ATTR(dw_bytes_perline, dwBytesPerLine, 32);

#undef UVCG_FRAME_ATTR

static ssize_t uvcg_frame_dw_frame_interval_show(struct config_item *item,
                                                 char *page)
{
        struct uvcg_frame *frm = to_uvcg_frame(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &frm->item.ci_group->cg_subsys->su_mutex;
        int result, i;
        char *pg = page;

        mutex_lock(su_mutex);   /* for navigating configfs hierarchy */

        opts_item = frm->item.ci_parent->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        for (result = 0, i = 0; i < frm->frame.b_frame_interval_type; ++i) {
                result += sprintf(pg, "%u\n", frm->dw_frame_interval[i]);
                pg = page + result;
        }
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);
        return result;
}

static ssize_t uvcg_frame_dw_frame_interval_store(struct config_item *item,
                                                  const char *page, size_t len)
{
        struct uvcg_frame *ch = to_uvcg_frame(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct uvcg_format *fmt;
        struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;
        int ret = 0, n = 0;
        u32 *frm_intrv, *tmp;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->item.ci_parent->ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);
        fmt = to_uvcg_format(ch->item.ci_parent);

        mutex_lock(&opts->lock);
        if (fmt->linked || opts->refcnt) {
                ret = -EBUSY;
                goto end;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_count_item_entries, &n, sizeof(u32));
        if (ret)
                goto end;

        tmp = frm_intrv = kcalloc(n, sizeof(u32), GFP_KERNEL);
        if (!frm_intrv) {
                ret = -ENOMEM;
                goto end;
        }

        ret = __uvcg_iter_item_entries(page, len, __uvcg_fill_item_entries, &tmp, sizeof(u32));
        if (ret) {
                kfree(frm_intrv);
                goto end;
        }

        kfree(ch->dw_frame_interval);
        ch->dw_frame_interval = frm_intrv;
        ch->frame.b_frame_interval_type = n;
        sort(ch->dw_frame_interval, n, sizeof(*ch->dw_frame_interval),
             uvcg_config_compare_u32, NULL);
        ret = len;

end:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

UVC_ATTR(uvcg_frame_, dw_frame_interval, dwFrameInterval);

static struct configfs_attribute *uvcg_frame_attrs1[] = {
        &uvcg_frame_attr_b_frame_index,
        &uvcg_frame_attr_bm_capabilities,
        &uvcg_frame_attr_w_width,
        &uvcg_frame_attr_w_height,
        &uvcg_frame_attr_dw_min_bit_rate,
        &uvcg_frame_attr_dw_max_bit_rate,
        &uvcg_frame_attr_dw_max_video_frame_buffer_size,
        &uvcg_frame_attr_dw_default_frame_interval,
        &uvcg_frame_attr_dw_frame_interval,
        NULL,
};

static struct configfs_attribute *uvcg_frame_attrs2[] = {
        &uvcg_frame_attr_b_frame_index,
        &uvcg_frame_attr_bm_capabilities,
        &uvcg_frame_attr_w_width,
        &uvcg_frame_attr_w_height,
        &uvcg_frame_attr_dw_min_bit_rate,
        &uvcg_frame_attr_dw_max_bit_rate,
        &uvcg_frame_attr_dw_default_frame_interval,
        &uvcg_frame_attr_dw_frame_interval,
        &uvcg_frame_attr_dw_bytes_perline,
        NULL,
};

static const struct config_item_type uvcg_frame_type1 = {
        .ct_item_ops    = &uvcg_config_item_ops,
        .ct_attrs       = uvcg_frame_attrs1,
        .ct_owner       = THIS_MODULE,
};

static const struct config_item_type uvcg_frame_type2 = {
        .ct_item_ops    = &uvcg_config_item_ops,
        .ct_attrs       = uvcg_frame_attrs2,
        .ct_owner       = THIS_MODULE,
};

static struct config_item *uvcg_frame_make(struct config_group *group,
                                           const char *name)
{
        struct uvcg_frame *h;
        struct uvcg_format *fmt;
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct uvcg_frame_ptr *frame_ptr;

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        h->frame.b_descriptor_type              = USB_DT_CS_INTERFACE;
        h->frame.b_frame_index                  = 1;
        h->frame.w_width                        = 640;
        h->frame.w_height                       = 360;
        h->frame.dw_min_bit_rate                = 18432000;
        h->frame.dw_max_bit_rate                = 55296000;
        h->frame.dw_max_video_frame_buffer_size = 460800;
        h->frame.dw_default_frame_interval      = 666666;
        h->frame.dw_bytes_perline               = 0;

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        fmt = to_uvcg_format(&group->cg_item);
        if (fmt->type == UVCG_UNCOMPRESSED) {
                h->frame.b_descriptor_subtype = UVC_VS_FRAME_UNCOMPRESSED;
                h->fmt_type = UVCG_UNCOMPRESSED;
        } else if (fmt->type == UVCG_MJPEG) {
                h->frame.b_descriptor_subtype = UVC_VS_FRAME_MJPEG;
                h->fmt_type = UVCG_MJPEG;
        } else if (fmt->type == UVCG_FRAMEBASED) {
                h->frame.b_descriptor_subtype = UVC_VS_FRAME_FRAME_BASED;
                h->fmt_type = UVCG_FRAMEBASED;
        } else {
                mutex_unlock(&opts->lock);
                kfree(h);
                return ERR_PTR(-EINVAL);
        }

        frame_ptr = kzalloc_obj(*frame_ptr);
        if (!frame_ptr) {
                mutex_unlock(&opts->lock);
                kfree(h);
                return ERR_PTR(-ENOMEM);
        }

        frame_ptr->frm = h;
        list_add_tail(&frame_ptr->entry, &fmt->frames);
        ++fmt->num_frames;
        mutex_unlock(&opts->lock);

        if (fmt->type == UVCG_FRAMEBASED)
                config_item_init_type_name(&h->item, name, &uvcg_frame_type2);
        else
                config_item_init_type_name(&h->item, name, &uvcg_frame_type1);

        return &h->item;
}

static void uvcg_frame_drop(struct config_group *group, struct config_item *item)
{
        struct uvcg_format *fmt;
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct uvcg_frame *target_frm = NULL;
        struct uvcg_frame_ptr *frame_ptr, *tmp;

        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        target_frm = container_of(item, struct uvcg_frame, item);
        fmt = to_uvcg_format(&group->cg_item);

        list_for_each_entry_safe(frame_ptr, tmp, &fmt->frames, entry)
                if (frame_ptr->frm == target_frm) {
                        list_del(&frame_ptr->entry);
                        kfree(frame_ptr);
                        --fmt->num_frames;
                        break;
                }
        mutex_unlock(&opts->lock);

        config_item_put(item);
}

static void uvcg_format_set_indices(struct config_group *fmt)
{
        struct config_item *ci;
        unsigned int i = 1;

        list_for_each_entry(ci, &fmt->cg_children, ci_entry) {
                struct uvcg_frame *frm;

                frm = to_uvcg_frame(ci);
                frm->frame.b_frame_index = i++;
        }
}

/* -----------------------------------------------------------------------------
 * streaming/uncompressed/<NAME>
 */

static const struct configfs_group_operations uvcg_uncompressed_group_ops = {
        .make_item              = uvcg_frame_make,
        .drop_item              = uvcg_frame_drop,
};

static ssize_t uvcg_uncompressed_guid_format_show(struct config_item *item,
                                                        char *page)
{
        struct uvcg_uncompressed *ch = to_uvcg_uncompressed(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        memcpy(page, ch->desc.guidFormat, sizeof(ch->desc.guidFormat));
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return sizeof(ch->desc.guidFormat);
}

static ssize_t uvcg_uncompressed_guid_format_store(struct config_item *item,
                                                   const char *page, size_t len)
{
        struct uvcg_uncompressed *ch = to_uvcg_uncompressed(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;
        const struct uvc_format_desc *format;
        u8 tmpguidFormat[sizeof(ch->desc.guidFormat)];
        int ret;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        if (ch->fmt.linked || opts->refcnt) {
                ret = -EBUSY;
                goto end;
        }

        memcpy(tmpguidFormat, page,
               min(sizeof(tmpguidFormat), len));

        format = uvc_format_by_guid(tmpguidFormat);
        if (!format) {
                ret = -EINVAL;
                goto end;
        }

        memcpy(ch->desc.guidFormat, tmpguidFormat,
               min(sizeof(ch->desc.guidFormat), len));
        ret = sizeof(ch->desc.guidFormat);

end:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

UVC_ATTR(uvcg_uncompressed_, guid_format, guidFormat);

#define UVCG_UNCOMPRESSED_ATTR_RO(cname, aname, bits)                   \
static ssize_t uvcg_uncompressed_##cname##_show(                        \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct uvcg_uncompressed *u = to_uvcg_uncompressed(item);       \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_uncompressed_, cname, aname);

#define UVCG_UNCOMPRESSED_ATTR(cname, aname, bits)                      \
static ssize_t uvcg_uncompressed_##cname##_show(                        \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct uvcg_uncompressed *u = to_uvcg_uncompressed(item);       \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t                                                          \
uvcg_uncompressed_##cname##_store(struct config_item *item,             \
                                    const char *page, size_t len)       \
{                                                                       \
        struct uvcg_uncompressed *u = to_uvcg_uncompressed(item);       \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int ret;                                                        \
        u8 num;                                                         \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (u->fmt.linked || opts->refcnt) {                            \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = kstrtou8(page, 0, &num);                                  \
        if (ret)                                                        \
                goto end;                                               \
                                                                        \
        /* index values in uvc are never 0 */                           \
        if (!num) {                                                     \
                ret = -EINVAL;                                          \
                goto end;                                               \
        }                                                               \
                                                                        \
        u->desc.aname = num;                                            \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        mutex_unlock(su_mutex);                                         \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(uvcg_uncompressed_, cname, aname);

UVCG_UNCOMPRESSED_ATTR_RO(b_format_index, bFormatIndex, 8);
UVCG_UNCOMPRESSED_ATTR(b_bits_per_pixel, bBitsPerPixel, 8);
UVCG_UNCOMPRESSED_ATTR(b_default_frame_index, bDefaultFrameIndex, 8);
UVCG_UNCOMPRESSED_ATTR_RO(b_aspect_ratio_x, bAspectRatioX, 8);
UVCG_UNCOMPRESSED_ATTR_RO(b_aspect_ratio_y, bAspectRatioY, 8);
UVCG_UNCOMPRESSED_ATTR_RO(bm_interlace_flags, bmInterlaceFlags, 8);

#undef UVCG_UNCOMPRESSED_ATTR
#undef UVCG_UNCOMPRESSED_ATTR_RO

static inline ssize_t
uvcg_uncompressed_bma_controls_show(struct config_item *item, char *page)
{
        struct uvcg_uncompressed *unc = to_uvcg_uncompressed(item);
        return uvcg_format_bma_controls_show(&unc->fmt, page);
}

static inline ssize_t
uvcg_uncompressed_bma_controls_store(struct config_item *item,
                                     const char *page, size_t len)
{
        struct uvcg_uncompressed *unc = to_uvcg_uncompressed(item);
        return uvcg_format_bma_controls_store(&unc->fmt, page, len);
}

UVC_ATTR(uvcg_uncompressed_, bma_controls, bmaControls);

static struct configfs_attribute *uvcg_uncompressed_attrs[] = {
        &uvcg_uncompressed_attr_b_format_index,
        &uvcg_uncompressed_attr_guid_format,
        &uvcg_uncompressed_attr_b_bits_per_pixel,
        &uvcg_uncompressed_attr_b_default_frame_index,
        &uvcg_uncompressed_attr_b_aspect_ratio_x,
        &uvcg_uncompressed_attr_b_aspect_ratio_y,
        &uvcg_uncompressed_attr_bm_interlace_flags,
        &uvcg_uncompressed_attr_bma_controls,
        NULL,
};

static const struct config_item_type uvcg_uncompressed_type = {
        .ct_item_ops    = &uvcg_format_item_operations,
        .ct_group_ops   = &uvcg_uncompressed_group_ops,
        .ct_attrs       = uvcg_uncompressed_attrs,
        .ct_owner       = THIS_MODULE,
};

static struct config_group *uvcg_uncompressed_make(struct config_group *group,
                                                   const char *name)
{
        static char guid[] = {
                'Y',  'U',  'Y',  '2', 0x00, 0x00, 0x10, 0x00,
                 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71
        };
        struct uvcg_color_matching *color_match;
        struct config_item *streaming;
        struct uvcg_uncompressed *h;

        streaming = group->cg_item.ci_parent;
        color_match = uvcg_format_get_default_color_match(streaming);
        if (!color_match)
                return ERR_PTR(-EINVAL);

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        h->desc.bLength                 = UVC_DT_FORMAT_UNCOMPRESSED_SIZE;
        h->desc.bDescriptorType         = USB_DT_CS_INTERFACE;
        h->desc.bDescriptorSubType      = UVC_VS_FORMAT_UNCOMPRESSED;
        memcpy(h->desc.guidFormat, guid, sizeof(guid));
        h->desc.bBitsPerPixel           = 16;
        h->desc.bDefaultFrameIndex      = 1;
        h->desc.bAspectRatioX           = 0;
        h->desc.bAspectRatioY           = 0;
        h->desc.bmInterlaceFlags        = 0;
        h->desc.bCopyProtect            = 0;

        INIT_LIST_HEAD(&h->fmt.frames);
        h->fmt.type = UVCG_UNCOMPRESSED;
        h->fmt.color_matching = color_match;
        color_match->refcnt++;
        config_group_init_type_name(&h->fmt.group, name,
                                    &uvcg_uncompressed_type);

        return &h->fmt.group;
}

static const struct configfs_group_operations uvcg_uncompressed_grp_ops = {
        .make_group             = uvcg_uncompressed_make,
};

static const struct uvcg_config_group_type uvcg_uncompressed_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_uncompressed_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "uncompressed",
};

/* -----------------------------------------------------------------------------
 * streaming/mjpeg/<NAME>
 */

static const struct configfs_group_operations uvcg_mjpeg_group_ops = {
        .make_item              = uvcg_frame_make,
        .drop_item              = uvcg_frame_drop,
};

#define UVCG_MJPEG_ATTR_RO(cname, aname, bits)                          \
static ssize_t uvcg_mjpeg_##cname##_show(struct config_item *item, char *page)\
{                                                                       \
        struct uvcg_mjpeg *u = to_uvcg_mjpeg(item);                     \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_mjpeg_, cname, aname)

#define UVCG_MJPEG_ATTR(cname, aname, bits)                             \
static ssize_t uvcg_mjpeg_##cname##_show(struct config_item *item, char *page)\
{                                                                       \
        struct uvcg_mjpeg *u = to_uvcg_mjpeg(item);                     \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t                                                          \
uvcg_mjpeg_##cname##_store(struct config_item *item,                    \
                           const char *page, size_t len)                \
{                                                                       \
        struct uvcg_mjpeg *u = to_uvcg_mjpeg(item);                     \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int ret;                                                        \
        u8 num;                                                         \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (u->fmt.linked || opts->refcnt) {                            \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = kstrtou8(page, 0, &num);                                  \
        if (ret)                                                        \
                goto end;                                               \
                                                                        \
        /* index values in uvc are never 0 */                           \
        if (!num) {                                                     \
                ret = -EINVAL;                                          \
                goto end;                                               \
        }                                                               \
                                                                        \
        u->desc.aname = num;                                            \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        mutex_unlock(su_mutex);                                         \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(uvcg_mjpeg_, cname, aname)

UVCG_MJPEG_ATTR_RO(b_format_index, bFormatIndex, 8);
UVCG_MJPEG_ATTR(b_default_frame_index, bDefaultFrameIndex, 8);
UVCG_MJPEG_ATTR_RO(bm_flags, bmFlags, 8);
UVCG_MJPEG_ATTR_RO(b_aspect_ratio_x, bAspectRatioX, 8);
UVCG_MJPEG_ATTR_RO(b_aspect_ratio_y, bAspectRatioY, 8);
UVCG_MJPEG_ATTR_RO(bm_interlace_flags, bmInterlaceFlags, 8);

#undef UVCG_MJPEG_ATTR
#undef UVCG_MJPEG_ATTR_RO

static inline ssize_t
uvcg_mjpeg_bma_controls_show(struct config_item *item, char *page)
{
        struct uvcg_mjpeg *u = to_uvcg_mjpeg(item);
        return uvcg_format_bma_controls_show(&u->fmt, page);
}

static inline ssize_t
uvcg_mjpeg_bma_controls_store(struct config_item *item,
                                     const char *page, size_t len)
{
        struct uvcg_mjpeg *u = to_uvcg_mjpeg(item);
        return uvcg_format_bma_controls_store(&u->fmt, page, len);
}

UVC_ATTR(uvcg_mjpeg_, bma_controls, bmaControls);

static struct configfs_attribute *uvcg_mjpeg_attrs[] = {
        &uvcg_mjpeg_attr_b_format_index,
        &uvcg_mjpeg_attr_b_default_frame_index,
        &uvcg_mjpeg_attr_bm_flags,
        &uvcg_mjpeg_attr_b_aspect_ratio_x,
        &uvcg_mjpeg_attr_b_aspect_ratio_y,
        &uvcg_mjpeg_attr_bm_interlace_flags,
        &uvcg_mjpeg_attr_bma_controls,
        NULL,
};

static const struct config_item_type uvcg_mjpeg_type = {
        .ct_item_ops    = &uvcg_format_item_operations,
        .ct_group_ops   = &uvcg_mjpeg_group_ops,
        .ct_attrs       = uvcg_mjpeg_attrs,
        .ct_owner       = THIS_MODULE,
};

static struct config_group *uvcg_mjpeg_make(struct config_group *group,
                                                   const char *name)
{
        struct uvcg_color_matching *color_match;
        struct config_item *streaming;
        struct uvcg_mjpeg *h;

        streaming = group->cg_item.ci_parent;
        color_match = uvcg_format_get_default_color_match(streaming);
        if (!color_match)
                return ERR_PTR(-EINVAL);

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        h->desc.bLength                 = UVC_DT_FORMAT_MJPEG_SIZE;
        h->desc.bDescriptorType         = USB_DT_CS_INTERFACE;
        h->desc.bDescriptorSubType      = UVC_VS_FORMAT_MJPEG;
        h->desc.bDefaultFrameIndex      = 1;
        h->desc.bAspectRatioX           = 0;
        h->desc.bAspectRatioY           = 0;
        h->desc.bmInterlaceFlags        = 0;
        h->desc.bCopyProtect            = 0;

        INIT_LIST_HEAD(&h->fmt.frames);
        h->fmt.type = UVCG_MJPEG;
        h->fmt.color_matching = color_match;
        color_match->refcnt++;
        config_group_init_type_name(&h->fmt.group, name,
                                    &uvcg_mjpeg_type);

        return &h->fmt.group;
}

static const struct configfs_group_operations uvcg_mjpeg_grp_ops = {
        .make_group             = uvcg_mjpeg_make,
};

static const struct uvcg_config_group_type uvcg_mjpeg_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_mjpeg_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "mjpeg",
};

/* -----------------------------------------------------------------------------
 * streaming/framebased/<NAME>
 */

static const struct configfs_group_operations uvcg_framebased_group_ops = {
        .make_item              = uvcg_frame_make,
        .drop_item              = uvcg_frame_drop,
};

#define UVCG_FRAMEBASED_ATTR_RO(cname, aname, bits)                     \
static ssize_t uvcg_framebased_##cname##_show(struct config_item *item, \
                char *page)                                             \
{                                                                       \
        struct uvcg_framebased *u = to_uvcg_framebased(item);           \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
UVC_ATTR_RO(uvcg_framebased_, cname, aname)

#define UVCG_FRAMEBASED_ATTR(cname, aname, bits)                        \
static ssize_t uvcg_framebased_##cname##_show(struct config_item *item, \
                char *page)                                             \
{                                                                       \
        struct uvcg_framebased *u = to_uvcg_framebased(item);           \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", le##bits##_to_cpu(u->desc.aname));\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t                                                          \
uvcg_framebased_##cname##_store(struct config_item *item,               \
                const char *page, size_t len)                           \
{                                                                       \
        struct uvcg_framebased *u = to_uvcg_framebased(item);           \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;     \
        int ret;                                                        \
        u8 num;                                                         \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (u->fmt.linked || opts->refcnt) {                            \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = kstrtou8(page, 0, &num);                                  \
        if (ret)                                                        \
                goto end;                                               \
                                                                        \
        if (num > 255) {                                                \
                ret = -EINVAL;                                          \
                goto end;                                               \
        }                                                               \
        u->desc.aname = num;                                            \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        mutex_unlock(su_mutex);                                         \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(uvcg_framebased_, cname, aname)

UVCG_FRAMEBASED_ATTR_RO(b_format_index, bFormatIndex, 8);
UVCG_FRAMEBASED_ATTR_RO(b_bits_per_pixel, bBitsPerPixel, 8);
UVCG_FRAMEBASED_ATTR(b_default_frame_index, bDefaultFrameIndex, 8);
UVCG_FRAMEBASED_ATTR_RO(b_aspect_ratio_x, bAspectRatioX, 8);
UVCG_FRAMEBASED_ATTR_RO(b_aspect_ratio_y, bAspectRatioY, 8);
UVCG_FRAMEBASED_ATTR_RO(bm_interface_flags, bmInterfaceFlags, 8);

#undef UVCG_FRAMEBASED_ATTR
#undef UVCG_FRAMEBASED_ATTR_RO

static ssize_t uvcg_framebased_guid_format_show(struct config_item *item,
                                                char *page)
{
        struct uvcg_framebased *ch = to_uvcg_framebased(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        memcpy(page, ch->desc.guidFormat, sizeof(ch->desc.guidFormat));
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return sizeof(ch->desc.guidFormat);
}

static ssize_t uvcg_framebased_guid_format_store(struct config_item *item,
                                                 const char *page, size_t len)
{
        struct uvcg_framebased *ch = to_uvcg_framebased(item);
        struct f_uvc_opts *opts;
        struct config_item *opts_item;
        struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;
        int ret;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        if (ch->fmt.linked || opts->refcnt) {
                ret = -EBUSY;
                goto end;
        }

        memcpy(ch->desc.guidFormat, page,
               min(sizeof(ch->desc.guidFormat), len));
        ret = sizeof(ch->desc.guidFormat);

end:
        mutex_unlock(&opts->lock);
        mutex_unlock(su_mutex);
        return ret;
}

UVC_ATTR(uvcg_framebased_, guid_format, guidFormat);

static inline ssize_t
uvcg_framebased_bma_controls_show(struct config_item *item, char *page)
{
        struct uvcg_framebased *u = to_uvcg_framebased(item);

        return uvcg_format_bma_controls_show(&u->fmt, page);
}

static inline ssize_t
uvcg_framebased_bma_controls_store(struct config_item *item,
                                   const char *page, size_t len)
{
        struct uvcg_framebased *u = to_uvcg_framebased(item);

        return uvcg_format_bma_controls_store(&u->fmt, page, len);
}

UVC_ATTR(uvcg_framebased_, bma_controls, bmaControls);

static struct configfs_attribute *uvcg_framebased_attrs[] = {
        &uvcg_framebased_attr_b_format_index,
        &uvcg_framebased_attr_b_default_frame_index,
        &uvcg_framebased_attr_b_bits_per_pixel,
        &uvcg_framebased_attr_b_aspect_ratio_x,
        &uvcg_framebased_attr_b_aspect_ratio_y,
        &uvcg_framebased_attr_bm_interface_flags,
        &uvcg_framebased_attr_bma_controls,
        &uvcg_framebased_attr_guid_format,
        NULL,
};

static const struct config_item_type uvcg_framebased_type = {
        .ct_item_ops    = &uvcg_config_item_ops,
        .ct_group_ops   = &uvcg_framebased_group_ops,
        .ct_attrs       = uvcg_framebased_attrs,
        .ct_owner       = THIS_MODULE,
};

static struct config_group *uvcg_framebased_make(struct config_group *group,
                                                 const char *name)
{
        static char guid[] = { /*Declear frame based as H264 format*/
                'H',  '2',  '6',  '4', 0x00, 0x00, 0x10, 0x00,
                0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71
        };
        struct uvcg_color_matching *color_match;
        struct config_item *streaming;
        struct uvcg_framebased *h;

        streaming = group->cg_item.ci_parent;
        color_match = uvcg_format_get_default_color_match(streaming);
        if (!color_match)
                return ERR_PTR(-EINVAL);

        h = kzalloc_obj(*h);
        if (!h)
                return ERR_PTR(-ENOMEM);

        h->desc.bLength                 = UVC_DT_FORMAT_FRAMEBASED_SIZE;
        h->desc.bDescriptorType         = USB_DT_CS_INTERFACE;
        h->desc.bDescriptorSubType      = UVC_VS_FORMAT_FRAME_BASED;
        memcpy(h->desc.guidFormat, guid, sizeof(guid));
        h->desc.bBitsPerPixel           = 0;
        h->desc.bDefaultFrameIndex      = 1;
        h->desc.bAspectRatioX           = 0;
        h->desc.bAspectRatioY           = 0;
        h->desc.bmInterfaceFlags        = 0;
        h->desc.bCopyProtect            = 0;
        h->desc.bVariableSize           = 1;

        INIT_LIST_HEAD(&h->fmt.frames);
        h->fmt.type = UVCG_FRAMEBASED;

        h->fmt.color_matching = color_match;
        color_match->refcnt++;
        config_group_init_type_name(&h->fmt.group, name,
                                    &uvcg_framebased_type);

        return &h->fmt.group;
}

static const struct configfs_group_operations uvcg_framebased_grp_ops = {
        .make_group             = uvcg_framebased_make,
};

static const struct uvcg_config_group_type uvcg_framebased_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_framebased_grp_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "framebased",
};

/* -----------------------------------------------------------------------------
 * streaming/color_matching/default
 */

#define UVCG_COLOR_MATCHING_ATTR(cname, aname, bits)                    \
static ssize_t uvcg_color_matching_##cname##_show(                      \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct config_group *group = to_config_group(item);             \
        struct uvcg_color_matching *color_match =                       \
                to_uvcg_color_matching(group);                          \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        int result;                                                     \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;     \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n",                                  \
                         le##bits##_to_cpu(color_match->desc.aname));   \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        mutex_unlock(su_mutex);                                         \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t uvcg_color_matching_##cname##_store(                     \
        struct config_item *item, const char *page, size_t len)         \
{                                                                       \
        struct config_group *group = to_config_group(item);             \
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;           \
        struct uvcg_color_matching *color_match =                       \
                to_uvcg_color_matching(group);                          \
        struct f_uvc_opts *opts;                                        \
        struct config_item *opts_item;                                  \
        int ret;                                                        \
        u##bits num;                                                    \
                                                                        \
        ret = kstrtou##bits(page, 0, &num);                             \
        if (ret)                                                        \
                return ret;                                             \
                                                                        \
        mutex_lock(su_mutex); /* for navigating configfs hierarchy */   \
                                                                        \
        if (color_match->refcnt) {                                      \
                ret = -EBUSY;                                           \
                goto unlock_su;                                         \
        }                                                               \
                                                                        \
        opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;     \
        opts = to_f_uvc_opts(opts_item);                                \
                                                                        \
        mutex_lock(&opts->lock);                                        \
                                                                        \
        color_match->desc.aname = num;                                  \
        ret = len;                                                      \
                                                                        \
        mutex_unlock(&opts->lock);                                      \
unlock_su:                                                              \
        mutex_unlock(su_mutex);                                         \
                                                                        \
        return ret;                                                     \
}                                                                       \
UVC_ATTR(uvcg_color_matching_, cname, aname)

UVCG_COLOR_MATCHING_ATTR(b_color_primaries, bColorPrimaries, 8);
UVCG_COLOR_MATCHING_ATTR(b_transfer_characteristics, bTransferCharacteristics, 8);
UVCG_COLOR_MATCHING_ATTR(b_matrix_coefficients, bMatrixCoefficients, 8);

#undef UVCG_COLOR_MATCHING_ATTR

static struct configfs_attribute *uvcg_color_matching_attrs[] = {
        &uvcg_color_matching_attr_b_color_primaries,
        &uvcg_color_matching_attr_b_transfer_characteristics,
        &uvcg_color_matching_attr_b_matrix_coefficients,
        NULL,
};

static void uvcg_color_matching_release(struct config_item *item)
{
        struct uvcg_color_matching *color_match =
                to_uvcg_color_matching(to_config_group(item));

        kfree(color_match);
}

static const struct configfs_item_operations uvcg_color_matching_item_ops = {
        .release        = uvcg_color_matching_release,
};

static const struct config_item_type uvcg_color_matching_type = {
        .ct_item_ops    = &uvcg_color_matching_item_ops,
        .ct_attrs       = uvcg_color_matching_attrs,
        .ct_owner       = THIS_MODULE,
};

/* -----------------------------------------------------------------------------
 * streaming/color_matching
 */

static struct config_group *uvcg_color_matching_make(struct config_group *group,
                                                     const char *name)
{
        struct uvcg_color_matching *color_match;

        color_match = kzalloc_obj(*color_match);
        if (!color_match)
                return ERR_PTR(-ENOMEM);

        color_match->desc.bLength = UVC_DT_COLOR_MATCHING_SIZE;
        color_match->desc.bDescriptorType = USB_DT_CS_INTERFACE;
        color_match->desc.bDescriptorSubType = UVC_VS_COLORFORMAT;

        config_group_init_type_name(&color_match->group, name,
                                    &uvcg_color_matching_type);

        return &color_match->group;
}

static const struct configfs_group_operations uvcg_color_matching_grp_group_ops = {
        .make_group     = uvcg_color_matching_make,
};

static int uvcg_color_matching_create_children(struct config_group *parent)
{
        struct uvcg_color_matching *color_match;

        color_match = kzalloc_obj(*color_match);
        if (!color_match)
                return -ENOMEM;

        color_match->desc.bLength = UVC_DT_COLOR_MATCHING_SIZE;
        color_match->desc.bDescriptorType = USB_DT_CS_INTERFACE;
        color_match->desc.bDescriptorSubType = UVC_VS_COLORFORMAT;
        color_match->desc.bColorPrimaries = UVC_COLOR_PRIMARIES_BT_709_SRGB;
        color_match->desc.bTransferCharacteristics = UVC_TRANSFER_CHARACTERISTICS_BT_709;
        color_match->desc.bMatrixCoefficients = UVC_MATRIX_COEFFICIENTS_SMPTE_170M;

        config_group_init_type_name(&color_match->group, "default",
                                    &uvcg_color_matching_type);
        configfs_add_default_group(&color_match->group, parent);

        return 0;
}

static const struct uvcg_config_group_type uvcg_color_matching_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_group_ops   = &uvcg_color_matching_grp_group_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "color_matching",
        .create_children = uvcg_color_matching_create_children,
};

/* -----------------------------------------------------------------------------
 * streaming/class/{fs|hs|ss}
 */

struct uvcg_streaming_class_group {
        struct config_group group;
        const char *name;
};

static inline struct uvc_descriptor_header
***__uvcg_get_stream_class_arr(struct config_item *i, struct f_uvc_opts *o)
{
        struct uvcg_streaming_class_group *group =
                container_of(i, struct uvcg_streaming_class_group,
                             group.cg_item);

        if (!strcmp(group->name, "fs"))
                return &o->uvc_fs_streaming_cls;

        if (!strcmp(group->name, "hs"))
                return &o->uvc_hs_streaming_cls;

        if (!strcmp(group->name, "ss"))
                return &o->uvc_ss_streaming_cls;

        return NULL;
}

enum uvcg_strm_type {
        UVCG_HEADER = 0,
        UVCG_FORMAT,
        UVCG_FRAME,
        UVCG_COLOR_MATCHING,
};

/*
 * Iterate over a hierarchy of streaming descriptors' config items.
 * The items are created by the user with configfs.
 *
 * It "processes" the header pointed to by @priv1, then for each format
 * that follows the header "processes" the format itself and then for
 * each frame inside a format "processes" the frame.
 *
 * As a "processing" function the @fun is used.
 *
 * __uvcg_iter_strm_cls() is used in two context: first, to calculate
 * the amount of memory needed for an array of streaming descriptors
 * and second, to actually fill the array.
 *
 * @h: streaming header pointer
 * @priv2: an "inout" parameter (the caller might want to see the changes to it)
 * @priv3: an "inout" parameter (the caller might want to see the changes to it)
 * @fun: callback function for processing each level of the hierarchy
 */
static int __uvcg_iter_strm_cls(struct uvcg_streaming_header *h,
        void *priv2, void *priv3,
        int (*fun)(void *, void *, void *, int, enum uvcg_strm_type type))
{
        struct uvcg_format_ptr *f;
        struct config_group *grp;
        struct config_item *item;
        struct uvcg_frame *frm;
        int ret, i, j;

        if (!fun)
                return -EINVAL;

        i = j = 0;
        ret = fun(h, priv2, priv3, 0, UVCG_HEADER);
        if (ret)
                return ret;
        list_for_each_entry(f, &h->formats, entry) {
                ret = fun(f->fmt, priv2, priv3, i++, UVCG_FORMAT);
                if (ret)
                        return ret;
                grp = &f->fmt->group;
                j = 0;
                list_for_each_entry(item, &grp->cg_children, ci_entry) {
                        frm = to_uvcg_frame(item);
                        ret = fun(frm, priv2, priv3, j++, UVCG_FRAME);
                        if (ret)
                                return ret;
                }

                ret = fun(f->fmt->color_matching, priv2, priv3, 0,
                          UVCG_COLOR_MATCHING);
                if (ret)
                        return ret;
        }

        return ret;
}

/*
 * Count how many bytes are needed for an array of streaming descriptors.
 *
 * @priv1: pointer to a header, format or frame
 * @priv2: inout parameter, accumulated size of the array
 * @priv3: inout parameter, accumulated number of the array elements
 * @n: unused, this function's prototype must match @fun in __uvcg_iter_strm_cls
 */
static int __uvcg_cnt_strm(void *priv1, void *priv2, void *priv3, int n,
                           enum uvcg_strm_type type)
{
        size_t *size = priv2;
        size_t *count = priv3;

        switch (type) {
        case UVCG_HEADER: {
                struct uvcg_streaming_header *h = priv1;

                *size += sizeof(h->desc);
                /* bmaControls */
                *size += h->num_fmt * UVCG_STREAMING_CONTROL_SIZE;
        }
        break;
        case UVCG_FORMAT: {
                struct uvcg_format *fmt = priv1;

                if (fmt->type == UVCG_UNCOMPRESSED) {
                        struct uvcg_uncompressed *u =
                                container_of(fmt, struct uvcg_uncompressed,
                                             fmt);

                        *size += sizeof(u->desc);
                } else if (fmt->type == UVCG_MJPEG) {
                        struct uvcg_mjpeg *m =
                                container_of(fmt, struct uvcg_mjpeg, fmt);

                        *size += sizeof(m->desc);
                } else if (fmt->type == UVCG_FRAMEBASED) {
                        struct uvcg_framebased *f =
                                container_of(fmt, struct uvcg_framebased, fmt);

                        *size += sizeof(f->desc);
                } else {
                        return -EINVAL;
                }
        }
        break;
        case UVCG_FRAME: {
                struct uvcg_frame *frm = priv1;
                int sz = sizeof(frm->dw_frame_interval);

                *size += sizeof(frm->frame);
                /*
                 * framebased has duplicate member with uncompressed and
                 * mjpeg, so minus it
                 */
                *size -= sizeof(u32);
                *size += frm->frame.b_frame_interval_type * sz;
        }
        break;
        case UVCG_COLOR_MATCHING: {
                struct uvcg_color_matching *color_match = priv1;

                *size += sizeof(color_match->desc);
        }
        break;
        }

        ++*count;

        return 0;
}

static int __uvcg_copy_framebased_desc(void *dest, struct uvcg_frame *frm,
                                       int sz)
{
        struct uvc_frame_framebased *desc = dest;

        desc->bLength = frm->frame.b_length;
        desc->bDescriptorType = frm->frame.b_descriptor_type;
        desc->bDescriptorSubType = frm->frame.b_descriptor_subtype;
        desc->bFrameIndex = frm->frame.b_frame_index;
        desc->bmCapabilities = frm->frame.bm_capabilities;
        desc->wWidth = frm->frame.w_width;
        desc->wHeight = frm->frame.w_height;
        desc->dwMinBitRate = frm->frame.dw_min_bit_rate;
        desc->dwMaxBitRate = frm->frame.dw_max_bit_rate;
        desc->dwDefaultFrameInterval = frm->frame.dw_default_frame_interval;
        desc->bFrameIntervalType = frm->frame.b_frame_interval_type;
        desc->dwBytesPerLine = frm->frame.dw_bytes_perline;

        return 0;
}

/*
 * Fill an array of streaming descriptors.
 *
 * @priv1: pointer to a header, format or frame
 * @priv2: inout parameter, pointer into a block of memory
 * @priv3: inout parameter, pointer to a 2-dimensional array
 */
static int __uvcg_fill_strm(void *priv1, void *priv2, void *priv3, int n,
                            enum uvcg_strm_type type)
{
        void **dest = priv2;
        struct uvc_descriptor_header ***array = priv3;
        size_t sz;

        **array = *dest;
        ++*array;

        switch (type) {
        case UVCG_HEADER: {
                struct uvc_input_header_descriptor *ihdr = *dest;
                struct uvcg_streaming_header *h = priv1;
                struct uvcg_format_ptr *f;

                memcpy(*dest, &h->desc, sizeof(h->desc));
                *dest += sizeof(h->desc);
                sz = UVCG_STREAMING_CONTROL_SIZE;
                list_for_each_entry(f, &h->formats, entry) {
                        memcpy(*dest, f->fmt->bmaControls, sz);
                        *dest += sz;
                }
                ihdr->bLength = sizeof(h->desc) + h->num_fmt * sz;
                ihdr->bNumFormats = h->num_fmt;
        }
        break;
        case UVCG_FORMAT: {
                struct uvcg_format *fmt = priv1;

                if (fmt->type == UVCG_UNCOMPRESSED) {
                        struct uvcg_uncompressed *u =
                                container_of(fmt, struct uvcg_uncompressed,
                                             fmt);

                        u->desc.bFormatIndex = n + 1;
                        u->desc.bNumFrameDescriptors = fmt->num_frames;
                        memcpy(*dest, &u->desc, sizeof(u->desc));
                        *dest += sizeof(u->desc);
                } else if (fmt->type == UVCG_MJPEG) {
                        struct uvcg_mjpeg *m =
                                container_of(fmt, struct uvcg_mjpeg, fmt);

                        m->desc.bFormatIndex = n + 1;
                        m->desc.bNumFrameDescriptors = fmt->num_frames;
                        memcpy(*dest, &m->desc, sizeof(m->desc));
                        *dest += sizeof(m->desc);
                } else if (fmt->type == UVCG_FRAMEBASED) {
                        struct uvcg_framebased *f =
                                container_of(fmt, struct uvcg_framebased,
                                             fmt);

                        f->desc.bFormatIndex = n + 1;
                        f->desc.bNumFrameDescriptors = fmt->num_frames;
                        memcpy(*dest, &f->desc, sizeof(f->desc));
                        *dest += sizeof(f->desc);
                } else {
                        return -EINVAL;
                }
        }
        break;
        case UVCG_FRAME: {
                struct uvcg_frame *frm = priv1;
                struct uvc_descriptor_header *h = *dest;

                sz = sizeof(frm->frame) - 4;
                if (frm->fmt_type != UVCG_FRAMEBASED)
                        memcpy(*dest, &frm->frame, sz);
                else
                        __uvcg_copy_framebased_desc(*dest, frm, sz);
                *dest += sz;
                sz = frm->frame.b_frame_interval_type *
                        sizeof(*frm->dw_frame_interval);
                memcpy(*dest, frm->dw_frame_interval, sz);
                *dest += sz;
                if (frm->fmt_type == UVCG_UNCOMPRESSED)
                        h->bLength = UVC_DT_FRAME_UNCOMPRESSED_SIZE(
                                frm->frame.b_frame_interval_type);
                else if (frm->fmt_type == UVCG_MJPEG)
                        h->bLength = UVC_DT_FRAME_MJPEG_SIZE(
                                        frm->frame.b_frame_interval_type);
                else if (frm->fmt_type == UVCG_FRAMEBASED)
                        h->bLength = UVC_DT_FRAME_FRAMEBASED_SIZE(
                                        frm->frame.b_frame_interval_type);
        }
        break;
        case UVCG_COLOR_MATCHING: {
                struct uvcg_color_matching *color_match = priv1;

                memcpy(*dest, &color_match->desc, sizeof(color_match->desc));
                *dest += sizeof(color_match->desc);
        }
        break;
        }

        return 0;
}

static int uvcg_streaming_class_allow_link(struct config_item *src,
                                           struct config_item *target)
{
        struct config_item *streaming, *header;
        struct f_uvc_opts *opts;
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvc_descriptor_header ***class_array, **cl_arr;
        struct uvcg_streaming_header *target_hdr;
        void *data, *data_save;
        size_t size = 0, count = 0;
        int ret = -EINVAL;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        streaming = src->ci_parent->ci_parent;
        header = config_group_find_item(to_config_group(streaming), "header");
        if (!header || target->ci_parent != header)
                goto out;

        opts = to_f_uvc_opts(streaming->ci_parent);

        mutex_lock(&opts->lock);

        class_array = __uvcg_get_stream_class_arr(src, opts);
        if (!class_array || *class_array || opts->refcnt) {
                ret = -EBUSY;
                goto unlock;
        }

        target_hdr = to_uvcg_streaming_header(target);
        ret = __uvcg_iter_strm_cls(target_hdr, &size, &count, __uvcg_cnt_strm);
        if (ret)
                goto unlock;

        count += 1; /* NULL */
        *class_array = kcalloc(count, sizeof(void *), GFP_KERNEL);
        if (!*class_array) {
                ret = -ENOMEM;
                goto unlock;
        }

        data = data_save = kzalloc(size, GFP_KERNEL);
        if (!data) {
                kfree(*class_array);
                *class_array = NULL;
                ret = -ENOMEM;
                goto unlock;
        }
        cl_arr = *class_array;
        ret = __uvcg_iter_strm_cls(target_hdr, &data, &cl_arr,
                                   __uvcg_fill_strm);
        if (ret) {
                kfree(*class_array);
                *class_array = NULL;
                /*
                 * __uvcg_fill_strm() called from __uvcg_iter_stream_cls()
                 * might have advanced the "data", so use a backup copy
                 */
                kfree(data_save);
                goto unlock;
        }

        ++target_hdr->linked;
        ret = 0;

unlock:
        mutex_unlock(&opts->lock);
out:
        config_item_put(header);
        mutex_unlock(su_mutex);
        return ret;
}

static void uvcg_streaming_class_drop_link(struct config_item *src,
                                          struct config_item *target)
{
        struct config_item *streaming, *header;
        struct f_uvc_opts *opts;
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct uvc_descriptor_header ***class_array;
        struct uvcg_streaming_header *target_hdr;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        streaming = src->ci_parent->ci_parent;
        header = config_group_find_item(to_config_group(streaming), "header");
        if (!header || target->ci_parent != header)
                goto out;

        opts = to_f_uvc_opts(streaming->ci_parent);

        mutex_lock(&opts->lock);

        class_array = __uvcg_get_stream_class_arr(src, opts);
        if (!class_array || !*class_array)
                goto unlock;

        if (opts->refcnt)
                goto unlock;

        target_hdr = to_uvcg_streaming_header(target);
        --target_hdr->linked;
        kfree(**class_array);
        kfree(*class_array);
        *class_array = NULL;

unlock:
        mutex_unlock(&opts->lock);
out:
        config_item_put(header);
        mutex_unlock(su_mutex);
}

static const struct configfs_item_operations uvcg_streaming_class_item_ops = {
        .release        = uvcg_config_item_release,
        .allow_link     = uvcg_streaming_class_allow_link,
        .drop_link      = uvcg_streaming_class_drop_link,
};

static const struct config_item_type uvcg_streaming_class_type = {
        .ct_item_ops    = &uvcg_streaming_class_item_ops,
        .ct_owner       = THIS_MODULE,
};

/* -----------------------------------------------------------------------------
 * streaming/class
 */

static int uvcg_streaming_class_create_children(struct config_group *parent)
{
        static const char * const names[] = { "fs", "hs", "ss" };
        unsigned int i;

        for (i = 0; i < ARRAY_SIZE(names); ++i) {
                struct uvcg_streaming_class_group *group;

                group = kzalloc_obj(*group);
                if (!group)
                        return -ENOMEM;

                group->name = names[i];

                config_group_init_type_name(&group->group, group->name,
                                            &uvcg_streaming_class_type);
                configfs_add_default_group(&group->group, parent);
        }

        return 0;
}

static const struct uvcg_config_group_type uvcg_streaming_class_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_owner       = THIS_MODULE,
        },
        .name = "class",
        .create_children = uvcg_streaming_class_create_children,
};

/* -----------------------------------------------------------------------------
 * streaming
 */

static ssize_t uvcg_default_streaming_b_interface_number_show(
        struct config_item *item, char *page)
{
        struct config_group *group = to_config_group(item);
        struct mutex *su_mutex = &group->cg_subsys->su_mutex;
        struct config_item *opts_item;
        struct f_uvc_opts *opts;
        int result = 0;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        opts_item = item->ci_parent;
        opts = to_f_uvc_opts(opts_item);

        mutex_lock(&opts->lock);
        result += sprintf(page, "%u\n", opts->streaming_interface);
        mutex_unlock(&opts->lock);

        mutex_unlock(su_mutex);

        return result;
}

UVC_ATTR_RO(uvcg_default_streaming_, b_interface_number, bInterfaceNumber);

static struct configfs_attribute *uvcg_default_streaming_attrs[] = {
        &uvcg_default_streaming_attr_b_interface_number,
        NULL,
};

static const struct uvcg_config_group_type uvcg_streaming_grp_type = {
        .type = {
                .ct_item_ops    = &uvcg_config_item_ops,
                .ct_attrs       = uvcg_default_streaming_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "streaming",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_streaming_header_grp_type,
                &uvcg_uncompressed_grp_type,
                &uvcg_mjpeg_grp_type,
                &uvcg_framebased_grp_type,
                &uvcg_color_matching_grp_type,
                &uvcg_streaming_class_grp_type,
                NULL,
        },
};

/* -----------------------------------------------------------------------------
 * UVC function
 */

static void uvc_func_item_release(struct config_item *item)
{
        struct f_uvc_opts *opts = to_f_uvc_opts(item);

        uvcg_config_remove_children(to_config_group(item));
        usb_put_function_instance(&opts->func_inst);
}

static int uvc_func_allow_link(struct config_item *src, struct config_item *tgt)
{
        struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
        struct gadget_string *string;
        struct config_item *strings;
        struct f_uvc_opts *opts;
        int ret = 0;

        mutex_lock(su_mutex); /* for navigating configfs hierarchy */

        /* Validate that the target is an entry in strings/<langid> */
        strings = config_group_find_item(to_config_group(src->ci_parent->ci_parent),
                                         "strings");
        if (!strings || tgt->ci_parent->ci_parent != strings) {
                ret = -EINVAL;
                goto put_strings;
        }

        string = to_gadget_string(tgt);

        opts = to_f_uvc_opts(src);
        mutex_lock(&opts->lock);

        if (!strcmp(tgt->ci_name, "iad_desc"))
                opts->iad_index = string->usb_string.id;
        else if (!strcmp(tgt->ci_name, "vs0_desc"))
                opts->vs0_index = string->usb_string.id;
        else if (!strcmp(tgt->ci_name, "vs1_desc"))
                opts->vs1_index = string->usb_string.id;
        else
                ret = -EINVAL;

        mutex_unlock(&opts->lock);

put_strings:
        config_item_put(strings);
        mutex_unlock(su_mutex);

        return ret;
}

static void uvc_func_drop_link(struct config_item *src, struct config_item *tgt)
{
        struct f_uvc_opts *opts;

        opts = to_f_uvc_opts(src);
        mutex_lock(&opts->lock);

        if (!strcmp(tgt->ci_name, "iad_desc"))
                opts->iad_index = 0;
        else if (!strcmp(tgt->ci_name, "vs0_desc"))
                opts->vs0_index = 0;
        else if (!strcmp(tgt->ci_name, "vs1_desc"))
                opts->vs1_index = 0;

        mutex_unlock(&opts->lock);
}

static const struct configfs_item_operations uvc_func_item_ops = {
        .release        = uvc_func_item_release,
        .allow_link     = uvc_func_allow_link,
        .drop_link      = uvc_func_drop_link,
};

#define UVCG_OPTS_ATTR(cname, aname, limit)                             \
static ssize_t f_uvc_opts_##cname##_show(                               \
        struct config_item *item, char *page)                           \
{                                                                       \
        struct f_uvc_opts *opts = to_f_uvc_opts(item);                  \
        int result;                                                     \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = sprintf(page, "%u\n", opts->cname);                    \
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t                                                          \
f_uvc_opts_##cname##_store(struct config_item *item,                    \
                           const char *page, size_t len)                \
{                                                                       \
        struct f_uvc_opts *opts = to_f_uvc_opts(item);                  \
        unsigned int num;                                               \
        int ret;                                                        \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (opts->refcnt) {                                             \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = kstrtouint(page, 0, &num);                                \
        if (ret)                                                        \
                goto end;                                               \
                                                                        \
        if (num > limit) {                                              \
                ret = -EINVAL;                                          \
                goto end;                                               \
        }                                                               \
        opts->cname = num;                                              \
        ret = len;                                                      \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(f_uvc_opts_, cname, cname)

UVCG_OPTS_ATTR(streaming_interval, streaming_interval, 16);
UVCG_OPTS_ATTR(streaming_maxpacket, streaming_maxpacket, 3072);
UVCG_OPTS_ATTR(streaming_maxburst, streaming_maxburst, 15);

#undef UVCG_OPTS_ATTR

#define UVCG_OPTS_STRING_ATTR(cname, aname)                             \
static ssize_t f_uvc_opts_string_##cname##_show(struct config_item *item,\
                                         char *page)                    \
{                                                                       \
        struct f_uvc_opts *opts = to_f_uvc_opts(item);                  \
        int result;                                                     \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        result = scnprintf(page, sizeof(opts->aname), "%s", opts->aname);\
        mutex_unlock(&opts->lock);                                      \
                                                                        \
        return result;                                                  \
}                                                                       \
                                                                        \
static ssize_t f_uvc_opts_string_##cname##_store(struct config_item *item,\
                                          const char *page, size_t len) \
{                                                                       \
        struct f_uvc_opts *opts = to_f_uvc_opts(item);                  \
        int size = min(sizeof(opts->aname), len + 1);                   \
        int ret = 0;                                                    \
                                                                        \
        mutex_lock(&opts->lock);                                        \
        if (opts->refcnt) {                                             \
                ret = -EBUSY;                                           \
                goto end;                                               \
        }                                                               \
                                                                        \
        ret = strscpy(opts->aname, page, size);                         \
        if (ret == -E2BIG)                                              \
                ret = size - 1;                                         \
                                                                        \
end:                                                                    \
        mutex_unlock(&opts->lock);                                      \
        return ret;                                                     \
}                                                                       \
                                                                        \
UVC_ATTR(f_uvc_opts_string_, cname, aname)

UVCG_OPTS_STRING_ATTR(function_name, function_name);

#undef UVCG_OPTS_STRING_ATTR

static struct configfs_attribute *uvc_attrs[] = {
        &f_uvc_opts_attr_streaming_interval,
        &f_uvc_opts_attr_streaming_maxpacket,
        &f_uvc_opts_attr_streaming_maxburst,
        &f_uvc_opts_string_attr_function_name,
        NULL,
};

static const struct uvcg_config_group_type uvc_func_type = {
        .type = {
                .ct_item_ops    = &uvc_func_item_ops,
                .ct_attrs       = uvc_attrs,
                .ct_owner       = THIS_MODULE,
        },
        .name = "",
        .children = (const struct uvcg_config_group_type*[]) {
                &uvcg_control_grp_type,
                &uvcg_streaming_grp_type,
                NULL,
        },
};

int uvcg_attach_configfs(struct f_uvc_opts *opts)
{
        int ret;

        config_group_init_type_name(&opts->func_inst.group, uvc_func_type.name,
                                    &uvc_func_type.type);

        ret = uvcg_config_create_children(&opts->func_inst.group,
                                          &uvc_func_type);
        if (ret < 0)
                config_group_put(&opts->func_inst.group);

        return ret;
}