// SPDX-License-Identifier: GPL-2.0
/*
 * USB Typec-C DisplayPort Alternate Mode driver
 *
 * Copyright (C) 2018 Intel Corporation
 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
 *
 * DisplayPort is trademark of VESA (www.vesa.org)
 */

#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/usb/pd_vdo.h>
#include <linux/usb/typec_dp.h>
#include <drm/drm_connector.h>
#include "displayport.h"

#define DP_HEADER(_dp, ver, cmd)        (VDO((_dp)->alt->svid, 1, ver, cmd)     \
                                         | VDO_OPOS(USB_TYPEC_DP_MODE))

enum {
        DP_CONF_USB,
        DP_CONF_DFP_D,
        DP_CONF_UFP_D,
        DP_CONF_DUAL_D,
};

/* Pin assignments that use USB3.1 Gen2 signaling to carry DP protocol */
#define DP_PIN_ASSIGN_GEN2_BR_MASK      (BIT(DP_PIN_ASSIGN_A) | \
                                         BIT(DP_PIN_ASSIGN_B))

/* Pin assignments that use DP v1.3 signaling to carry DP protocol */
#define DP_PIN_ASSIGN_DP_BR_MASK        (BIT(DP_PIN_ASSIGN_C) | \
                                         BIT(DP_PIN_ASSIGN_D) | \
                                         BIT(DP_PIN_ASSIGN_E) | \
                                         BIT(DP_PIN_ASSIGN_F))

/* DP only pin assignments */
#define DP_PIN_ASSIGN_DP_ONLY_MASK      (BIT(DP_PIN_ASSIGN_A) | \
                                         BIT(DP_PIN_ASSIGN_C) | \
                                         BIT(DP_PIN_ASSIGN_E))

/* Pin assignments where one channel is for USB */
#define DP_PIN_ASSIGN_MULTI_FUNC_MASK   (BIT(DP_PIN_ASSIGN_B) | \
                                         BIT(DP_PIN_ASSIGN_D) | \
                                         BIT(DP_PIN_ASSIGN_F))

enum dp_state {
        DP_STATE_IDLE,
        DP_STATE_ENTER,
        DP_STATE_ENTER_PRIME,
        DP_STATE_UPDATE,
        DP_STATE_CONFIGURE,
        DP_STATE_CONFIGURE_PRIME,
        DP_STATE_EXIT,
        DP_STATE_EXIT_PRIME,
};

struct dp_altmode {
        struct typec_displayport_data data;
        struct typec_displayport_data data_prime;

        enum dp_state state;
        bool hpd;
        bool pending_hpd;
        u32 irq_hpd_count;
        /*
         * hpd is mandatory for irq_hpd assertion, so irq_hpd also needs its own pending flag if
         * both hpd and irq_hpd are asserted in the first Status Update before the pin assignment
         * is configured.
         */
        bool pending_irq_hpd;

        struct mutex lock; /* device lock */
        struct work_struct work;
        struct typec_altmode *alt;
        const struct typec_altmode *port;
        struct fwnode_handle *connector_fwnode;
        struct typec_altmode *plug_prime;
};

static int dp_altmode_notify(struct dp_altmode *dp)
{
        unsigned long conf;
        u8 state;

        if (dp->data.conf) {
                state = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
                conf = TYPEC_MODAL_STATE(state);
        } else {
                conf = TYPEC_STATE_USB;
        }

        return typec_altmode_notify(dp->alt, conf, &dp->data);
}

static int dp_altmode_configure(struct dp_altmode *dp, u8 con)
{
        u8 pin_assign = 0;
        u32 conf;
        u32 signal;

        /* DP Signalling */
        signal = DP_CAP_DP_SIGNALLING(dp->port->vdo) & DP_CAP_DP_SIGNALLING(dp->alt->vdo);
        if (dp->plug_prime)
                signal &= DP_CAP_DP_SIGNALLING(dp->plug_prime->vdo);

        conf = signal << DP_CONF_SIGNALLING_SHIFT;

        switch (con) {
        case DP_STATUS_CON_DISABLED:
                return 0;
        case DP_STATUS_CON_DFP_D:
                conf |= DP_CONF_UFP_U_AS_DFP_D;
                pin_assign = DP_CAP_UFP_D_PIN_ASSIGN(dp->alt->vdo) &
                             DP_CAP_DFP_D_PIN_ASSIGN(dp->port->vdo);
                /* Account for active cable capabilities */
                if (dp->plug_prime)
                        pin_assign &= DP_CAP_DFP_D_PIN_ASSIGN(dp->plug_prime->vdo);
                break;
        case DP_STATUS_CON_UFP_D:
        case DP_STATUS_CON_BOTH: /* NOTE: First acting as DP source */
                conf |= DP_CONF_UFP_U_AS_UFP_D;
                pin_assign = DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo) &
                                 DP_CAP_PIN_ASSIGN_DFP_D(dp->port->vdo);
                /* Account for active cable capabilities */
                if (dp->plug_prime)
                        pin_assign &= DP_CAP_UFP_D_PIN_ASSIGN(dp->plug_prime->vdo);
                break;
        default:
                break;
        }

        /* Determining the initial pin assignment. */
        if (!DP_CONF_GET_PIN_ASSIGN(dp->data.conf)) {
                /* Is USB together with DP preferred */
                if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC &&
                    pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK)
                        pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK;
                else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK) {
                        pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK;
                        /* Default to pin assign C if available */
                        if (pin_assign & BIT(DP_PIN_ASSIGN_C))
                                pin_assign = BIT(DP_PIN_ASSIGN_C);
                }

                if (!pin_assign)
                        return -EINVAL;

                conf |= DP_CONF_SET_PIN_ASSIGN(pin_assign);
        }

        dp->data.conf = conf;
        if (dp->plug_prime)
                dp->data_prime.conf = conf;

        return 0;
}

static int dp_altmode_status_update(struct dp_altmode *dp)
{
        bool configured = !!DP_CONF_GET_PIN_ASSIGN(dp->data.conf);
        bool hpd = !!(dp->data.status & DP_STATUS_HPD_STATE);
        bool irq_hpd = !!(dp->data.status & DP_STATUS_IRQ_HPD);
        u8 con = DP_STATUS_CONNECTION(dp->data.status);
        int ret = 0;

        if (configured && (dp->data.status & DP_STATUS_SWITCH_TO_USB)) {
                dp->data.conf = 0;
                dp->data_prime.conf = 0;
                dp->state = dp->plug_prime ? DP_STATE_CONFIGURE_PRIME :
                                             DP_STATE_CONFIGURE;
        } else if (dp->data.status & DP_STATUS_EXIT_DP_MODE) {
                dp->state = DP_STATE_EXIT;
        } else if (!(con & DP_CONF_CURRENTLY(dp->data.conf))) {
                ret = dp_altmode_configure(dp, con);
                if (!ret) {
                        dp->state = dp->plug_prime ? DP_STATE_CONFIGURE_PRIME :
                                                     DP_STATE_CONFIGURE;
                        if (dp->hpd != hpd) {
                                dp->hpd = hpd;
                                dp->pending_hpd = true;
                        }
                        if (dp->hpd && dp->pending_hpd && irq_hpd)
                                dp->pending_irq_hpd = true;
                }
        } else {
                drm_connector_oob_hotplug_event(dp->connector_fwnode,
                                                hpd ? connector_status_connected :
                                                      connector_status_disconnected);
                dp->hpd = hpd;
                sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
                if (hpd && irq_hpd) {
                        dp->irq_hpd_count++;
                        sysfs_notify(&dp->alt->dev.kobj, "displayport", "irq_hpd");
                }
        }

        return ret;
}

static int dp_altmode_configured(struct dp_altmode *dp)
{
        sysfs_notify(&dp->alt->dev.kobj, "displayport", "configuration");
        sysfs_notify(&dp->alt->dev.kobj, "displayport", "pin_assignment");
        /*
         * If the DFP_D/UFP_D sends a change in HPD when first notifying the
         * DisplayPort driver that it is connected, then we wait until
         * configuration is complete to signal HPD.
         */
        if (dp->pending_hpd) {
                drm_connector_oob_hotplug_event(dp->connector_fwnode,
                                                connector_status_connected);
                sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
                dp->pending_hpd = false;
                if (dp->pending_irq_hpd) {
                        dp->irq_hpd_count++;
                        sysfs_notify(&dp->alt->dev.kobj, "displayport", "irq_hpd");
                        dp->pending_irq_hpd = false;
                }
        }

        return dp_altmode_notify(dp);
}

static int dp_altmode_configure_vdm(struct dp_altmode *dp, u32 conf)
{
        int svdm_version = typec_altmode_get_svdm_version(dp->alt);
        u32 header;
        int ret;

        if (svdm_version < 0)
                return svdm_version;

        header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);
        ret = typec_altmode_notify(dp->alt, TYPEC_STATE_SAFE, &dp->data);
        if (ret) {
                dev_err(&dp->alt->dev,
                        "unable to put to connector to safe mode\n");
                return ret;
        }

        ret = typec_altmode_vdm(dp->alt, header, &conf, 2);
        if (ret)
                dp_altmode_notify(dp);

        return ret;
}

static int dp_altmode_configure_vdm_cable(struct dp_altmode *dp, u32 conf)
{
        int svdm_version = typec_altmode_get_cable_svdm_version(dp->plug_prime);
        u32 header;

        if (svdm_version < 0)
                return svdm_version;

        header = DP_HEADER(dp, svdm_version, DP_CMD_CONFIGURE);

        return typec_cable_altmode_vdm(dp->plug_prime, TYPEC_PLUG_SOP_P, header, &conf, 2);
}

static void dp_altmode_work(struct work_struct *work)
{
        struct dp_altmode *dp = container_of(work, struct dp_altmode, work);
        int svdm_version;
        u32 header;
        u32 vdo;
        int ret;

        mutex_lock(&dp->lock);

        switch (dp->state) {
        case DP_STATE_ENTER:
                ret = typec_altmode_enter(dp->alt, NULL);
                if (ret && ret != -EBUSY)
                        dev_err(&dp->alt->dev, "failed to enter mode: %d\n", ret);
                break;
        case DP_STATE_ENTER_PRIME:
                ret = typec_cable_altmode_enter(dp->alt, TYPEC_PLUG_SOP_P, NULL);
                /*
                 * If we fail to enter Alt Mode on SOP', then we should drop the
                 * plug from the driver and attempt to run the driver without
                 * it.
                 */
                if (ret && ret != -EBUSY) {
                        dev_err(&dp->alt->dev, "plug failed to enter mode\n");
                        dp->state = DP_STATE_ENTER;
                        goto disable_prime;
                }
                break;
        case DP_STATE_UPDATE:
                svdm_version = typec_altmode_get_svdm_version(dp->alt);
                if (svdm_version < 0)
                        break;
                header = DP_HEADER(dp, svdm_version, DP_CMD_STATUS_UPDATE);
                vdo = 1;
                ret = typec_altmode_vdm(dp->alt, header, &vdo, 2);
                if (ret)
                        dev_err(&dp->alt->dev,
                                "unable to send Status Update command (%d)\n",
                                ret);
                break;
        case DP_STATE_CONFIGURE:
                ret = dp_altmode_configure_vdm(dp, dp->data.conf);
                if (ret)
                        dev_err(&dp->alt->dev,
                                "unable to send Configure command (%d)\n", ret);
                break;
        case DP_STATE_CONFIGURE_PRIME:
                ret = dp_altmode_configure_vdm_cable(dp, dp->data_prime.conf);
                if (ret) {
                        dev_err(&dp->plug_prime->dev,
                                "unable to send Configure command (%d)\n",
                                ret);
                        dp->state = DP_STATE_CONFIGURE;
                        goto disable_prime;
                }
                break;
        case DP_STATE_EXIT:
                if (typec_altmode_exit(dp->alt))
                        dev_err(&dp->alt->dev, "Exit Mode Failed!\n");
                break;
        case DP_STATE_EXIT_PRIME:
                if (typec_cable_altmode_exit(dp->plug_prime, TYPEC_PLUG_SOP_P))
                        dev_err(&dp->plug_prime->dev, "Exit Mode Failed!\n");
                break;
        default:
                break;
        }

        dp->state = DP_STATE_IDLE;

        mutex_unlock(&dp->lock);
        return;

disable_prime:
        typec_altmode_put_plug(dp->plug_prime);
        dp->plug_prime = NULL;
        schedule_work(&dp->work);
        mutex_unlock(&dp->lock);
}

static void dp_altmode_attention(struct typec_altmode *alt, const u32 vdo)
{
        struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
        u8 old_state;

        mutex_lock(&dp->lock);

        old_state = dp->state;
        dp->data.status = vdo;

        if (old_state != DP_STATE_IDLE)
                dev_warn(&alt->dev, "ATTENTION while processing state %d\n",
                         old_state);

        if (dp_altmode_status_update(dp))
                dev_warn(&alt->dev, "%s: status update failed\n", __func__);

        if (dp_altmode_notify(dp))
                dev_err(&alt->dev, "%s: notification failed\n", __func__);

        if (old_state == DP_STATE_IDLE && dp->state != DP_STATE_IDLE)
                schedule_work(&dp->work);

        mutex_unlock(&dp->lock);
}

static int dp_altmode_vdm(struct typec_altmode *alt,
                          const u32 hdr, const u32 *vdo, int count)
{
        struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
        int cmd_type = PD_VDO_CMDT(hdr);
        int cmd = PD_VDO_CMD(hdr);
        int ret = 0;

        mutex_lock(&dp->lock);

        if (dp->state != DP_STATE_IDLE) {
                ret = -EBUSY;
                goto err_unlock;
        }

        switch (cmd_type) {
        case CMDT_RSP_ACK:
                switch (cmd) {
                case CMD_ENTER_MODE:
                        typec_altmode_update_active(alt, true);
                        dp->state = DP_STATE_UPDATE;
                        break;
                case CMD_EXIT_MODE:
                        typec_altmode_update_active(alt, false);
                        dp->data.status = 0;
                        dp->data.conf = 0;
                        if (dp->hpd) {
                                drm_connector_oob_hotplug_event(dp->connector_fwnode,
                                                                connector_status_disconnected);
                                dp->hpd = false;
                                sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
                        }
                        if (dp->plug_prime)
                                dp->state = DP_STATE_EXIT_PRIME;
                        break;
                case DP_CMD_STATUS_UPDATE:
                        if (count < 2)
                                break;
                        dp->data.status = *vdo;
                        ret = dp_altmode_status_update(dp);
                        break;
                case DP_CMD_CONFIGURE:
                        ret = dp_altmode_configured(dp);
                        break;
                default:
                        break;
                }
                break;
        case CMDT_RSP_NAK:
                switch (cmd) {
                case DP_CMD_STATUS_UPDATE:
                        dp->state = DP_STATE_EXIT;
                        break;
                case DP_CMD_CONFIGURE:
                        dp->data.conf = 0;
                        ret = dp_altmode_configured(dp);
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        if (dp->state != DP_STATE_IDLE)
                schedule_work(&dp->work);

err_unlock:
        mutex_unlock(&dp->lock);
        return ret;
}

static int dp_cable_altmode_vdm(struct typec_altmode *alt, enum typec_plug_index sop,
                                const u32 hdr, const u32 *vdo, int count)
{
        struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
        int cmd_type = PD_VDO_CMDT(hdr);
        int cmd = PD_VDO_CMD(hdr);
        int ret = 0;

        mutex_lock(&dp->lock);

        if (dp->state != DP_STATE_IDLE) {
                ret = -EBUSY;
                goto err_unlock;
        }

        switch (cmd_type) {
        case CMDT_RSP_ACK:
                switch (cmd) {
                case CMD_ENTER_MODE:
                        typec_altmode_update_active(dp->plug_prime, true);
                        dp->state = DP_STATE_ENTER;
                        break;
                case CMD_EXIT_MODE:
                        dp->data_prime.status = 0;
                        dp->data_prime.conf = 0;
                        typec_altmode_update_active(dp->plug_prime, false);
                        break;
                case DP_CMD_CONFIGURE:
                        dp->state = DP_STATE_CONFIGURE;
                        break;
                default:
                        break;
                }
                break;
        case CMDT_RSP_NAK:
                switch (cmd) {
                case DP_CMD_CONFIGURE:
                        dp->data_prime.conf = 0;
                        /* Attempt to configure on SOP, drop plug */
                        typec_altmode_put_plug(dp->plug_prime);
                        dp->plug_prime = NULL;
                        dp->state = DP_STATE_CONFIGURE;
                        break;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        if (dp->state != DP_STATE_IDLE)
                schedule_work(&dp->work);

err_unlock:
        mutex_unlock(&dp->lock);
        return ret;
}

static int dp_altmode_activate(struct typec_altmode *alt, int activate)
{
        struct dp_altmode *dp = typec_altmode_get_drvdata(alt);
        int ret;

        if (activate) {
                if (dp->plug_prime) {
                        ret = typec_cable_altmode_enter(alt, TYPEC_PLUG_SOP_P, NULL);
                        if (ret < 0) {
                                typec_altmode_put_plug(dp->plug_prime);
                                dp->plug_prime = NULL;
                        } else {
                                return ret;
                        }
                }
                return typec_altmode_enter(alt, NULL);
        } else {
                return typec_altmode_exit(alt);
        }
}

static const struct typec_altmode_ops dp_altmode_ops = {
        .attention = dp_altmode_attention,
        .vdm = dp_altmode_vdm,
        .activate = dp_altmode_activate,
};

static const struct typec_cable_ops dp_cable_ops = {
        .vdm = dp_cable_altmode_vdm,
};

static const char * const configurations[] = {
        [DP_CONF_USB]   = "USB",
        [DP_CONF_DFP_D] = "source",
        [DP_CONF_UFP_D] = "sink",
};

static ssize_t
configuration_store(struct device *dev, struct device_attribute *attr,
                    const char *buf, size_t size)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);
        u32 conf;
        u32 cap;
        int con;
        int ret = 0;

        con = sysfs_match_string(configurations, buf);
        if (con < 0)
                return con;

        mutex_lock(&dp->lock);

        if (dp->state != DP_STATE_IDLE) {
                ret = -EBUSY;
                goto err_unlock;
        }

        cap = DP_CAP_CAPABILITY(dp->alt->vdo);

        if ((con == DP_CONF_DFP_D && !(cap & DP_CAP_DFP_D)) ||
            (con == DP_CONF_UFP_D && !(cap & DP_CAP_UFP_D))) {
                ret = -EINVAL;
                goto err_unlock;
        }

        conf = dp->data.conf & ~DP_CONF_DUAL_D;
        conf |= con;

        if (dp->alt->active) {
                ret = dp_altmode_configure_vdm(dp, conf);
                if (ret)
                        goto err_unlock;
        }

        dp->data.conf = conf;

err_unlock:
        mutex_unlock(&dp->lock);

        return ret ? ret : size;
}

static ssize_t configuration_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);
        int len;
        u8 cap;
        u8 cur;
        int i;

        mutex_lock(&dp->lock);

        cap = DP_CAP_CAPABILITY(dp->alt->vdo);
        cur = DP_CONF_CURRENTLY(dp->data.conf);

        len = sprintf(buf, "%s ", cur ? "USB" : "[USB]");

        for (i = 1; i < ARRAY_SIZE(configurations); i++) {
                if (i == cur)
                        len += sprintf(buf + len, "[%s] ", configurations[i]);
                else if ((i == DP_CONF_DFP_D && cap & DP_CAP_DFP_D) ||
                         (i == DP_CONF_UFP_D && cap & DP_CAP_UFP_D))
                        len += sprintf(buf + len, "%s ", configurations[i]);
        }

        mutex_unlock(&dp->lock);

        buf[len - 1] = '\n';
        return len;
}
static DEVICE_ATTR_RW(configuration);

static const char * const pin_assignments[] = {
        [DP_PIN_ASSIGN_A] = "A",
        [DP_PIN_ASSIGN_B] = "B",
        [DP_PIN_ASSIGN_C] = "C",
        [DP_PIN_ASSIGN_D] = "D",
        [DP_PIN_ASSIGN_E] = "E",
        [DP_PIN_ASSIGN_F] = "F",
};

/*
 * Helper function to extract a peripheral's currently supported
 * Pin Assignments from its DisplayPort alternate mode state.
 */
static u8 get_current_pin_assignments(struct dp_altmode *dp)
{
        if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_UFP_U_AS_DFP_D)
                return DP_CAP_PIN_ASSIGN_DFP_D(dp->alt->vdo);
        else
                return DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo);
}

static ssize_t
pin_assignment_store(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t size)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);
        u8 assignments;
        u32 conf;
        int ret;

        ret = sysfs_match_string(pin_assignments, buf);
        if (ret < 0)
                return ret;

        conf = DP_CONF_SET_PIN_ASSIGN(BIT(ret));
        ret = 0;

        mutex_lock(&dp->lock);

        if (conf & dp->data.conf)
                goto out_unlock;

        if (dp->state != DP_STATE_IDLE) {
                ret = -EBUSY;
                goto out_unlock;
        }

        assignments = get_current_pin_assignments(dp);

        if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
                ret = -EINVAL;
                goto out_unlock;
        }

        conf |= dp->data.conf & ~DP_CONF_PIN_ASSIGNEMENT_MASK;

        /* Only send Configure command if a configuration has been set */
        if (dp->alt->active && DP_CONF_CURRENTLY(dp->data.conf)) {
                /* todo: send manual configure over SOP'*/
                ret = dp_altmode_configure_vdm(dp, conf);
                if (ret)
                        goto out_unlock;
        }

        dp->data.conf = conf;

out_unlock:
        mutex_unlock(&dp->lock);

        return ret ? ret : size;
}

static ssize_t pin_assignment_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);
        u8 assignments;
        int len = 0;
        u8 cur;
        int i;

        mutex_lock(&dp->lock);

        cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));

        assignments = get_current_pin_assignments(dp);

        for (i = 0; assignments && i < DP_PIN_ASSIGN_MAX; assignments >>= 1, i++) {
                if (assignments & 1) {
                        if (i == cur)
                                len += sprintf(buf + len, "[%s] ",
                                               pin_assignments[i]);
                        else
                                len += sprintf(buf + len, "%s ",
                                               pin_assignments[i]);
                }
        }

        mutex_unlock(&dp->lock);

        /* get_current_pin_assignments can return 0 when no matching pin assignments are found */
        if (len == 0)
                len++;

        buf[len - 1] = '\n';
        return len;
}
static DEVICE_ATTR_RW(pin_assignment);

static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%d\n", dp->hpd);
}
static DEVICE_ATTR_RO(hpd);

static ssize_t irq_hpd_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct dp_altmode *dp = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%d\n", dp->irq_hpd_count);
}
static DEVICE_ATTR_RO(irq_hpd);

static struct attribute *displayport_attrs[] = {
        &dev_attr_configuration.attr,
        &dev_attr_pin_assignment.attr,
        &dev_attr_hpd.attr,
        &dev_attr_irq_hpd.attr,
        NULL
};

static const struct attribute_group displayport_group = {
        .name = "displayport",
        .attrs = displayport_attrs,
};

static const struct attribute_group *displayport_groups[] = {
        &displayport_group,
        NULL,
};

int dp_altmode_probe(struct typec_altmode *alt)
{
        const struct typec_altmode *port = typec_altmode_get_partner(alt);
        struct typec_altmode *plug = typec_altmode_get_plug(alt, TYPEC_PLUG_SOP_P);
        struct fwnode_handle *fwnode;
        struct dp_altmode *dp;

        /* Port can only be DFP_U. */
        if (typec_altmode_get_data_role(alt) != TYPEC_HOST)
                return -EPROTO;

        /* Make sure we have compatible pin configurations */
        if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &
              DP_CAP_PIN_ASSIGN_UFP_D(alt->vdo)) &&
            !(DP_CAP_PIN_ASSIGN_UFP_D(port->vdo) &
              DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo))) {
                typec_altmode_put_plug(plug);
                return -ENODEV;
        }

        dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);
        if (!dp) {
                typec_altmode_put_plug(plug);
                return -ENOMEM;
        }

        INIT_WORK(&dp->work, dp_altmode_work);
        mutex_init(&dp->lock);
        dp->port = port;
        dp->alt = alt;

        alt->desc = "DisplayPort";
        typec_altmode_set_ops(alt, &dp_altmode_ops);

        if (plug) {
                plug->desc = "Displayport";
                plug->cable_ops = &dp_cable_ops;
        }

        dp->plug_prime = plug;

        fwnode = dev_fwnode(alt->dev.parent->parent); /* typec_port fwnode */
        if (fwnode_property_present(fwnode, "displayport"))
                dp->connector_fwnode = fwnode_find_reference(fwnode, "displayport", 0);
        else
                dp->connector_fwnode = fwnode_handle_get(fwnode); /* embedded DP */
        if (IS_ERR(dp->connector_fwnode))
                dp->connector_fwnode = NULL;

        typec_altmode_set_drvdata(alt, dp);
        if (plug)
                typec_altmode_set_drvdata(plug, dp);

        if (!alt->mode_selection) {
                dp->state = plug ? DP_STATE_ENTER_PRIME : DP_STATE_ENTER;
                schedule_work(&dp->work);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dp_altmode_probe);

void dp_altmode_remove(struct typec_altmode *alt)
{
        struct dp_altmode *dp = typec_altmode_get_drvdata(alt);

        cancel_work_sync(&dp->work);
        typec_altmode_put_plug(dp->plug_prime);

        if (dp->connector_fwnode) {
                drm_connector_oob_hotplug_event(dp->connector_fwnode,
                                                connector_status_disconnected);

                fwnode_handle_put(dp->connector_fwnode);
        }
}
EXPORT_SYMBOL_GPL(dp_altmode_remove);

static const struct typec_device_id dp_typec_id[] = {
        { USB_TYPEC_DP_SID },
        { },
};
MODULE_DEVICE_TABLE(typec, dp_typec_id);

static struct typec_altmode_driver dp_altmode_driver = {
        .id_table = dp_typec_id,
        .probe = dp_altmode_probe,
        .remove = dp_altmode_remove,
        .driver = {
                .name = "typec_displayport",
                .dev_groups = displayport_groups,
        },
};
module_typec_altmode_driver(dp_altmode_driver);

MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("DisplayPort Alternate Mode");