// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Main USB camera driver
 *
 * Copyright (C) 2008-2011 Jean-François Moine <http://moinejf.free.fr>
 *
 * Camera button input handling by Márton Németh
 * Copyright (C) 2009-2010 Márton Németh <nm127@freemail.hu>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#define GSPCA_VERSION   "2.14.0"

#include <linux/init.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include <linux/io.h>
#include <asm/page.h>
#include <linux/uaccess.h>
#include <linux/ktime.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>

#include "gspca.h"

#if IS_ENABLED(CONFIG_INPUT)
#include <linux/input.h>
#include <linux/usb/input.h>
#endif

/* global values */
#define DEF_NURBS 3             /* default number of URBs */
#if DEF_NURBS > MAX_NURBS
#error "DEF_NURBS too big"
#endif

MODULE_AUTHOR("Jean-François Moine <http://moinejf.free.fr>");
MODULE_DESCRIPTION("GSPCA USB Camera Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(GSPCA_VERSION);

int gspca_debug;
EXPORT_SYMBOL(gspca_debug);

static void PDEBUG_MODE(struct gspca_dev *gspca_dev, int debug, char *txt,
                        __u32 pixfmt, int w, int h)
{
        if ((pixfmt >> 24) >= '0' && (pixfmt >> 24) <= 'z') {
                gspca_dbg(gspca_dev, debug, "%s %c%c%c%c %dx%d\n",
                          txt,
                          pixfmt & 0xff,
                          (pixfmt >> 8) & 0xff,
                          (pixfmt >> 16) & 0xff,
                          pixfmt >> 24,
                          w, h);
        } else {
                gspca_dbg(gspca_dev, debug, "%s 0x%08x %dx%d\n",
                          txt,
                          pixfmt,
                          w, h);
        }
}

/* specific memory types - !! should be different from V4L2_MEMORY_xxx */
#define GSPCA_MEMORY_NO 0       /* V4L2_MEMORY_xxx starts from 1 */
#define GSPCA_MEMORY_READ 7

/*
 * Input and interrupt endpoint handling functions
 */
#if IS_ENABLED(CONFIG_INPUT)
static void int_irq(struct urb *urb)
{
        struct gspca_dev *gspca_dev = (struct gspca_dev *) urb->context;
        int ret;

        ret = urb->status;
        switch (ret) {
        case 0:
                if (gspca_dev->sd_desc->int_pkt_scan(gspca_dev,
                    urb->transfer_buffer, urb->actual_length) < 0) {
                        gspca_err(gspca_dev, "Unknown packet received\n");
                }
                break;

        case -ENOENT:
        case -ECONNRESET:
        case -ENODEV:
        case -ESHUTDOWN:
                /* Stop is requested either by software or hardware is gone,
                 * keep the ret value non-zero and don't resubmit later.
                 */
                break;

        default:
                gspca_err(gspca_dev, "URB error %i, resubmitting\n",
                          urb->status);
                urb->status = 0;
                ret = 0;
        }

        if (ret == 0) {
                ret = usb_submit_urb(urb, GFP_ATOMIC);
                if (ret < 0)
                        pr_err("Resubmit URB failed with error %i\n", ret);
        }
}

static int gspca_input_connect(struct gspca_dev *dev)
{
        struct input_dev *input_dev;
        int err = 0;

        dev->input_dev = NULL;
        if (dev->sd_desc->int_pkt_scan || dev->sd_desc->other_input)  {
                input_dev = input_allocate_device();
                if (!input_dev)
                        return -ENOMEM;

                usb_make_path(dev->dev, dev->phys, sizeof(dev->phys));
                strlcat(dev->phys, "/input0", sizeof(dev->phys));

                input_dev->name = dev->sd_desc->name;
                input_dev->phys = dev->phys;

                usb_to_input_id(dev->dev, &input_dev->id);

                input_dev->evbit[0] = BIT_MASK(EV_KEY);
                input_dev->keybit[BIT_WORD(KEY_CAMERA)] = BIT_MASK(KEY_CAMERA);
                input_dev->dev.parent = &dev->dev->dev;

                err = input_register_device(input_dev);
                if (err) {
                        pr_err("Input device registration failed with error %i\n",
                               err);
                        input_dev->dev.parent = NULL;
                        input_free_device(input_dev);
                } else {
                        dev->input_dev = input_dev;
                }
        }

        return err;
}

static int alloc_and_submit_int_urb(struct gspca_dev *gspca_dev,
                          struct usb_endpoint_descriptor *ep)
{
        unsigned int buffer_len;
        int interval;
        struct urb *urb;
        struct usb_device *dev;
        void *buffer = NULL;
        int ret = -EINVAL;

        buffer_len = le16_to_cpu(ep->wMaxPacketSize);
        interval = ep->bInterval;
        gspca_dbg(gspca_dev, D_CONF, "found int in endpoint: 0x%x, buffer_len=%u, interval=%u\n",
                  ep->bEndpointAddress, buffer_len, interval);

        dev = gspca_dev->dev;

        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!urb) {
                ret = -ENOMEM;
                goto error;
        }

        buffer = usb_alloc_coherent(dev, buffer_len,
                                GFP_KERNEL, &urb->transfer_dma);
        if (!buffer) {
                ret = -ENOMEM;
                goto error_buffer;
        }
        usb_fill_int_urb(urb, dev,
                usb_rcvintpipe(dev, ep->bEndpointAddress),
                buffer, buffer_len,
                int_irq, (void *)gspca_dev, interval);
        urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
        ret = usb_submit_urb(urb, GFP_KERNEL);
        if (ret < 0) {
                gspca_err(gspca_dev, "submit int URB failed with error %i\n",
                          ret);
                goto error_submit;
        }
        gspca_dev->int_urb = urb;
        return ret;

error_submit:
        usb_free_coherent(dev,
                          urb->transfer_buffer_length,
                          urb->transfer_buffer,
                          urb->transfer_dma);
error_buffer:
        usb_free_urb(urb);
error:
        return ret;
}

static void gspca_input_create_urb(struct gspca_dev *gspca_dev)
{
        struct usb_interface *intf;
        struct usb_host_interface *intf_desc;
        struct usb_endpoint_descriptor *ep;
        int i;

        if (gspca_dev->sd_desc->int_pkt_scan)  {
                intf = usb_ifnum_to_if(gspca_dev->dev, gspca_dev->iface);
                intf_desc = intf->cur_altsetting;
                for (i = 0; i < intf_desc->desc.bNumEndpoints; i++) {
                        ep = &intf_desc->endpoint[i].desc;
                        if (usb_endpoint_dir_in(ep) &&
                            usb_endpoint_xfer_int(ep)) {

                                alloc_and_submit_int_urb(gspca_dev, ep);
                                break;
                        }
                }
        }
}

static void gspca_input_destroy_urb(struct gspca_dev *gspca_dev)
{
        struct urb *urb;

        urb = gspca_dev->int_urb;
        if (urb) {
                gspca_dev->int_urb = NULL;
                usb_kill_urb(urb);
                usb_free_coherent(gspca_dev->dev,
                                  urb->transfer_buffer_length,
                                  urb->transfer_buffer,
                                  urb->transfer_dma);
                usb_free_urb(urb);
        }
}
#else
static inline void gspca_input_destroy_urb(struct gspca_dev *gspca_dev)
{
}

static inline void gspca_input_create_urb(struct gspca_dev *gspca_dev)
{
}

static inline int gspca_input_connect(struct gspca_dev *dev)
{
        return 0;
}
#endif

/*
 * fill a video frame from an URB and resubmit
 */
static void fill_frame(struct gspca_dev *gspca_dev,
                        struct urb *urb)
{
        u8 *data;               /* address of data in the iso message */
        int i, len, st;
        cam_pkt_op pkt_scan;

        if (urb->status != 0) {
                if (urb->status == -ESHUTDOWN)
                        return;         /* disconnection */
#ifdef CONFIG_PM
                if (gspca_dev->frozen)
                        return;
#endif
                gspca_err(gspca_dev, "urb status: %d\n", urb->status);
                urb->status = 0;
                goto resubmit;
        }
        pkt_scan = gspca_dev->sd_desc->pkt_scan;
        for (i = 0; i < urb->number_of_packets; i++) {
                len = urb->iso_frame_desc[i].actual_length;

                /* check the packet status and length */
                st = urb->iso_frame_desc[i].status;
                if (st) {
                        gspca_dbg(gspca_dev, D_PACK, "ISOC data error: [%d] len=%d, status=%d\n",
                               i, len, st);
                        gspca_dev->last_packet_type = DISCARD_PACKET;
                        continue;
                }
                if (len == 0) {
                        if (gspca_dev->empty_packet == 0)
                                gspca_dev->empty_packet = 1;
                        continue;
                }

                /* let the packet be analyzed by the subdriver */
                gspca_dbg(gspca_dev, D_PACK, "packet [%d] o:%d l:%d\n",
                          i, urb->iso_frame_desc[i].offset, len);
                data = (u8 *) urb->transfer_buffer
                                        + urb->iso_frame_desc[i].offset;
                pkt_scan(gspca_dev, data, len);
        }

resubmit:
        if (!gspca_dev->streaming)
                return;
        /* resubmit the URB */
        st = usb_submit_urb(urb, GFP_ATOMIC);
        if (st < 0)
                pr_err("usb_submit_urb() ret %d\n", st);
}

/*
 * ISOC message interrupt from the USB device
 *
 * Analyse each packet and call the subdriver for copy to the frame buffer.
 */
static void isoc_irq(struct urb *urb)
{
        struct gspca_dev *gspca_dev = (struct gspca_dev *) urb->context;

        gspca_dbg(gspca_dev, D_PACK, "isoc irq\n");
        if (!gspca_dev->streaming)
                return;
        fill_frame(gspca_dev, urb);
}

/*
 * bulk message interrupt from the USB device
 */
static void bulk_irq(struct urb *urb)
{
        struct gspca_dev *gspca_dev = (struct gspca_dev *) urb->context;
        int st;

        gspca_dbg(gspca_dev, D_PACK, "bulk irq\n");
        if (!gspca_dev->streaming)
                return;
        switch (urb->status) {
        case 0:
                break;
        case -ESHUTDOWN:
                return;         /* disconnection */
        default:
#ifdef CONFIG_PM
                if (gspca_dev->frozen)
                        return;
#endif
                gspca_err(gspca_dev, "urb status: %d\n", urb->status);
                urb->status = 0;
                goto resubmit;
        }

        gspca_dbg(gspca_dev, D_PACK, "packet l:%d\n", urb->actual_length);
        gspca_dev->sd_desc->pkt_scan(gspca_dev,
                                urb->transfer_buffer,
                                urb->actual_length);

resubmit:
        if (!gspca_dev->streaming)
                return;
        /* resubmit the URB */
        if (gspca_dev->cam.bulk_nurbs != 0) {
                st = usb_submit_urb(urb, GFP_ATOMIC);
                if (st < 0)
                        pr_err("usb_submit_urb() ret %d\n", st);
        }
}

/*
 * add data to the current frame
 *
 * This function is called by the subdrivers at interrupt level.
 *
 * To build a frame, these ones must add
 *      - one FIRST_PACKET
 *      - 0 or many INTER_PACKETs
 *      - one LAST_PACKET
 * DISCARD_PACKET invalidates the whole frame.
 */
void gspca_frame_add(struct gspca_dev *gspca_dev,
                        enum gspca_packet_type packet_type,
                        const u8 *data,
                        int len)
{
        struct gspca_buffer *buf;
        unsigned long flags;

        gspca_dbg(gspca_dev, D_PACK, "add t:%d l:%d\n", packet_type, len);

        spin_lock_irqsave(&gspca_dev->qlock, flags);
        buf = list_first_entry_or_null(&gspca_dev->buf_list,
                                       typeof(*buf), list);
        spin_unlock_irqrestore(&gspca_dev->qlock, flags);

        if (packet_type == FIRST_PACKET) {
                /* if there is no queued buffer, discard the whole frame */
                if (!buf) {
                        gspca_dev->last_packet_type = DISCARD_PACKET;
                        gspca_dev->sequence++;
                        return;
                }
                gspca_dev->image = vb2_plane_vaddr(&buf->vb.vb2_buf, 0);
                gspca_dev->image_len = 0;
        } else {
                switch (gspca_dev->last_packet_type) {
                case DISCARD_PACKET:
                        if (packet_type == LAST_PACKET) {
                                gspca_dev->last_packet_type = packet_type;
                                gspca_dev->image = NULL;
                                gspca_dev->image_len = 0;
                        }
                        return;
                case LAST_PACKET:
                        return;
                }
        }

        /* append the packet to the frame buffer */
        if (len > 0) {
                if (gspca_dev->image_len + len > PAGE_ALIGN(gspca_dev->pixfmt.sizeimage)) {
                        gspca_err(gspca_dev, "frame overflow %d > %d\n",
                                  gspca_dev->image_len + len,
                                  PAGE_ALIGN(gspca_dev->pixfmt.sizeimage));
                        packet_type = DISCARD_PACKET;
                } else {
/* !! image is NULL only when last pkt is LAST or DISCARD
                        if (gspca_dev->image == NULL) {
                                pr_err("gspca_frame_add() image == NULL\n");
                                return;
                        }
 */
                        memcpy(gspca_dev->image + gspca_dev->image_len,
                                data, len);
                        gspca_dev->image_len += len;
                }
        }
        gspca_dev->last_packet_type = packet_type;

        /* if last packet, invalidate packet concatenation until
         * next first packet, wake up the application and advance
         * in the queue */
        if (packet_type == LAST_PACKET) {
                if (gspca_dev->image_len > gspca_dev->pixfmt.sizeimage)
                        gspca_dev->image_len = gspca_dev->pixfmt.sizeimage;
                spin_lock_irqsave(&gspca_dev->qlock, flags);
                list_del(&buf->list);
                spin_unlock_irqrestore(&gspca_dev->qlock, flags);
                buf->vb.vb2_buf.timestamp = ktime_get_ns();
                vb2_set_plane_payload(&buf->vb.vb2_buf, 0,
                                      gspca_dev->image_len);
                buf->vb.sequence = gspca_dev->sequence++;
                buf->vb.field = V4L2_FIELD_NONE;
                gspca_dbg(gspca_dev, D_FRAM, "frame complete len:%d\n",
                          gspca_dev->image_len);
                vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
                gspca_dev->image = NULL;
                gspca_dev->image_len = 0;
        }
}
EXPORT_SYMBOL(gspca_frame_add);

static void destroy_urbs(struct gspca_dev *gspca_dev)
{
        struct urb *urb;
        unsigned int i;

        gspca_dbg(gspca_dev, D_STREAM, "kill transfer\n");

        /* Killing all URBs guarantee that no URB completion
         * handler is running. Therefore, there shouldn't
         * be anyone trying to access gspca_dev->urb[i]
         */
        for (i = 0; i < MAX_NURBS; i++)
                usb_kill_urb(gspca_dev->urb[i]);

        gspca_dbg(gspca_dev, D_STREAM, "releasing urbs\n");
        for (i = 0; i < MAX_NURBS; i++) {
                urb = gspca_dev->urb[i];
                if (!urb)
                        continue;
                gspca_dev->urb[i] = NULL;
                usb_free_coherent(gspca_dev->dev,
                                  urb->transfer_buffer_length,
                                  urb->transfer_buffer,
                                  urb->transfer_dma);
                usb_free_urb(urb);
        }
}

static int gspca_set_alt0(struct gspca_dev *gspca_dev)
{
        int ret;

        if (gspca_dev->alt == 0)
                return 0;
        ret = usb_set_interface(gspca_dev->dev, gspca_dev->iface, 0);
        if (ret < 0)
                pr_err("set alt 0 err %d\n", ret);
        return ret;
}

/*
 * look for an input transfer endpoint in an alternate setting.
 *
 * If xfer_ep is invalid, return the first valid ep found, otherwise
 * look for exactly the ep with address equal to xfer_ep.
 */
static struct usb_host_endpoint *alt_xfer(struct usb_host_interface *alt,
                                          int xfer, int xfer_ep)
{
        struct usb_host_endpoint *ep;
        int i, attr;

        for (i = 0; i < alt->desc.bNumEndpoints; i++) {
                ep = &alt->endpoint[i];
                attr = ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
                if (attr == xfer
                    && ep->desc.wMaxPacketSize != 0
                    && usb_endpoint_dir_in(&ep->desc)
                    && (xfer_ep < 0 || ep->desc.bEndpointAddress == xfer_ep))
                        return ep;
        }
        return NULL;
}

/* compute the minimum bandwidth for the current transfer */
static u32 which_bandwidth(struct gspca_dev *gspca_dev)
{
        u32 bandwidth;

        /* get the (max) image size */
        bandwidth = gspca_dev->pixfmt.sizeimage;

        /* if the image is compressed, estimate its mean size */
        if (!gspca_dev->cam.needs_full_bandwidth &&
            bandwidth < gspca_dev->pixfmt.width *
                                gspca_dev->pixfmt.height)
                bandwidth = bandwidth * 3 / 8;  /* 0.375 */

        /* estimate the frame rate */
        if (gspca_dev->sd_desc->get_streamparm) {
                struct v4l2_streamparm parm;

                gspca_dev->sd_desc->get_streamparm(gspca_dev, &parm);
                bandwidth *= parm.parm.capture.timeperframe.denominator;
                bandwidth /= parm.parm.capture.timeperframe.numerator;
        } else {

                /* don't hope more than 15 fps with USB 1.1 and
                 * image resolution >= 640x480 */
                if (gspca_dev->pixfmt.width >= 640
                 && gspca_dev->dev->speed == USB_SPEED_FULL)
                        bandwidth *= 15;                /* 15 fps */
                else
                        bandwidth *= 30;                /* 30 fps */
        }

        gspca_dbg(gspca_dev, D_STREAM, "min bandwidth: %d\n", bandwidth);
        return bandwidth;
}

/* endpoint table */
#define MAX_ALT 16
struct ep_tb_s {
        u32 alt;
        u32 bandwidth;
};

/*
 * build the table of the endpoints
 * and compute the minimum bandwidth for the image transfer
 */
static int build_isoc_ep_tb(struct gspca_dev *gspca_dev,
                        struct usb_interface *intf,
                        struct ep_tb_s *ep_tb)
{
        struct usb_host_endpoint *ep;
        int i, j, nbalt, psize, found;
        u32 bandwidth, last_bw;

        nbalt = intf->num_altsetting;
        if (nbalt > MAX_ALT)
                nbalt = MAX_ALT;        /* fixme: should warn */

        /* build the endpoint table */
        i = 0;
        last_bw = 0;
        for (;;) {
                ep_tb->bandwidth = 2000 * 2000 * 120;
                found = 0;
                for (j = 0; j < nbalt; j++) {
                        ep = alt_xfer(&intf->altsetting[j],
                                      USB_ENDPOINT_XFER_ISOC,
                                      gspca_dev->xfer_ep);
                        if (ep == NULL)
                                continue;
                        if (ep->desc.bInterval == 0) {
                                pr_err("alt %d iso endp with 0 interval\n", j);
                                continue;
                        }
                        psize = le16_to_cpu(ep->desc.wMaxPacketSize);
                        psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
                        bandwidth = psize * 1000;
                        if (gspca_dev->dev->speed == USB_SPEED_HIGH
                         || gspca_dev->dev->speed >= USB_SPEED_SUPER)
                                bandwidth *= 8;
                        bandwidth /= 1 << (ep->desc.bInterval - 1);
                        if (bandwidth <= last_bw)
                                continue;
                        if (bandwidth < ep_tb->bandwidth) {
                                ep_tb->bandwidth = bandwidth;
                                ep_tb->alt = j;
                                found = 1;
                        }
                }
                if (!found)
                        break;
                gspca_dbg(gspca_dev, D_STREAM, "alt %d bandwidth %d\n",
                          ep_tb->alt, ep_tb->bandwidth);
                last_bw = ep_tb->bandwidth;
                i++;
                ep_tb++;
        }

        /*
         * If the camera:
         * has a usb audio class interface (a built in usb mic); and
         * is a usb 1 full speed device; and
         * uses the max full speed iso bandwidth; and
         * and has more than 1 alt setting
         * then skip the highest alt setting to spare bandwidth for the mic
         */
        if (gspca_dev->audio &&
                        gspca_dev->dev->speed == USB_SPEED_FULL &&
                        last_bw >= 1000000 &&
                        i > 1) {
                gspca_dbg(gspca_dev, D_STREAM, "dev has usb audio, skipping highest alt\n");
                i--;
                ep_tb--;
        }

        /* get the requested bandwidth and start at the highest atlsetting */
        bandwidth = which_bandwidth(gspca_dev);
        ep_tb--;
        while (i > 1) {
                ep_tb--;
                if (ep_tb->bandwidth < bandwidth)
                        break;
                i--;
        }
        return i;
}

/*
 * create the URBs for image transfer
 */
static int create_urbs(struct gspca_dev *gspca_dev,
                        struct usb_host_endpoint *ep)
{
        struct urb *urb;
        int n, nurbs, i, psize, npkt, bsize;

        /* calculate the packet size and the number of packets */
        psize = le16_to_cpu(ep->desc.wMaxPacketSize);

        if (!gspca_dev->cam.bulk) {             /* isoc */

                /* See paragraph 5.9 / table 5-11 of the usb 2.0 spec. */
                if (gspca_dev->pkt_size == 0)
                        psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));
                else
                        psize = gspca_dev->pkt_size;
                npkt = gspca_dev->cam.npkt;
                if (npkt == 0)
                        npkt = 32;              /* default value */
                bsize = psize * npkt;
                gspca_dbg(gspca_dev, D_STREAM,
                          "isoc %d pkts size %d = bsize:%d\n",
                          npkt, psize, bsize);
                nurbs = DEF_NURBS;
        } else {                                /* bulk */
                npkt = 0;
                bsize = gspca_dev->cam.bulk_size;
                if (bsize == 0)
                        bsize = psize;
                gspca_dbg(gspca_dev, D_STREAM, "bulk bsize:%d\n", bsize);
                if (gspca_dev->cam.bulk_nurbs != 0)
                        nurbs = gspca_dev->cam.bulk_nurbs;
                else
                        nurbs = 1;
        }

        for (n = 0; n < nurbs; n++) {
                urb = usb_alloc_urb(npkt, GFP_KERNEL);
                if (!urb)
                        return -ENOMEM;
                gspca_dev->urb[n] = urb;
                urb->transfer_buffer = usb_alloc_coherent(gspca_dev->dev,
                                                bsize,
                                                GFP_KERNEL,
                                                &urb->transfer_dma);

                if (urb->transfer_buffer == NULL) {
                        pr_err("usb_alloc_coherent failed\n");
                        return -ENOMEM;
                }
                urb->dev = gspca_dev->dev;
                urb->context = gspca_dev;
                urb->transfer_buffer_length = bsize;
                if (npkt != 0) {                /* ISOC */
                        urb->pipe = usb_rcvisocpipe(gspca_dev->dev,
                                                    ep->desc.bEndpointAddress);
                        urb->transfer_flags = URB_ISO_ASAP
                                        | URB_NO_TRANSFER_DMA_MAP;
                        urb->interval = 1 << (ep->desc.bInterval - 1);
                        urb->complete = isoc_irq;
                        urb->number_of_packets = npkt;
                        for (i = 0; i < npkt; i++) {
                                urb->iso_frame_desc[i].length = psize;
                                urb->iso_frame_desc[i].offset = psize * i;
                        }
                } else {                /* bulk */
                        urb->pipe = usb_rcvbulkpipe(gspca_dev->dev,
                                                ep->desc.bEndpointAddress);
                        urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
                        urb->complete = bulk_irq;
                }
        }
        return 0;
}

/* Note: both the queue and the usb locks should be held when calling this */
static void gspca_stream_off(struct gspca_dev *gspca_dev)
{
        gspca_dev->streaming = false;
        gspca_dev->usb_err = 0;
        if (gspca_dev->sd_desc->stopN)
                gspca_dev->sd_desc->stopN(gspca_dev);
        destroy_urbs(gspca_dev);
        gspca_input_destroy_urb(gspca_dev);
        gspca_set_alt0(gspca_dev);
        if (gspca_dev->present)
                gspca_input_create_urb(gspca_dev);
        if (gspca_dev->sd_desc->stop0)
                gspca_dev->sd_desc->stop0(gspca_dev);
        gspca_dbg(gspca_dev, D_STREAM, "stream off OK\n");
}

/*
 * start the USB transfer
 */
static int gspca_init_transfer(struct gspca_dev *gspca_dev)
{
        struct usb_interface *intf;
        struct usb_host_endpoint *ep;
        struct urb *urb;
        struct ep_tb_s ep_tb[MAX_ALT];
        int n, ret, xfer, alt, alt_idx;

        /* reset the streaming variables */
        gspca_dev->image = NULL;
        gspca_dev->image_len = 0;
        gspca_dev->last_packet_type = DISCARD_PACKET;

        gspca_dev->usb_err = 0;

        /* do the specific subdriver stuff before endpoint selection */
        intf = usb_ifnum_to_if(gspca_dev->dev, gspca_dev->iface);
        gspca_dev->alt = gspca_dev->cam.bulk ? intf->num_altsetting : 0;
        if (gspca_dev->sd_desc->isoc_init) {
                ret = gspca_dev->sd_desc->isoc_init(gspca_dev);
                if (ret < 0)
                        return ret;
        }
        xfer = gspca_dev->cam.bulk ? USB_ENDPOINT_XFER_BULK
                                   : USB_ENDPOINT_XFER_ISOC;

        /* if bulk or the subdriver forced an altsetting, get the endpoint */
        if (gspca_dev->alt != 0) {
                gspca_dev->alt--;       /* (previous version compatibility) */
                ep = alt_xfer(&intf->altsetting[gspca_dev->alt], xfer,
                              gspca_dev->xfer_ep);
                if (ep == NULL) {
                        pr_err("bad altsetting %d\n", gspca_dev->alt);
                        return -EIO;
                }
                ep_tb[0].alt = gspca_dev->alt;
                alt_idx = 1;
        } else {
                /* else, compute the minimum bandwidth
                 * and build the endpoint table */
                alt_idx = build_isoc_ep_tb(gspca_dev, intf, ep_tb);
                if (alt_idx <= 0) {
                        pr_err("no transfer endpoint found\n");
                        return -EIO;
                }
        }

        /* set the highest alternate setting and
         * loop until urb submit succeeds */
        gspca_input_destroy_urb(gspca_dev);

        gspca_dev->alt = ep_tb[--alt_idx].alt;
        alt = -1;
        for (;;) {
                if (alt != gspca_dev->alt) {
                        alt = gspca_dev->alt;
                        if (intf->num_altsetting > 1) {
                                ret = usb_set_interface(gspca_dev->dev,
                                                        gspca_dev->iface,
                                                        alt);
                                if (ret < 0) {
                                        if (ret == -ENOSPC)
                                                goto retry; /*fixme: ugly*/
                                        pr_err("set alt %d err %d\n", alt, ret);
                                        goto out;
                                }
                        }
                }
                if (!gspca_dev->cam.no_urb_create) {
                        gspca_dbg(gspca_dev, D_STREAM, "init transfer alt %d\n",
                                  alt);
                        ret = create_urbs(gspca_dev,
                                alt_xfer(&intf->altsetting[alt], xfer,
                                         gspca_dev->xfer_ep));
                        if (ret < 0) {
                                destroy_urbs(gspca_dev);
                                goto out;
                        }
                }

                /* clear the bulk endpoint */
                if (gspca_dev->cam.bulk)
                        usb_clear_halt(gspca_dev->dev,
                                        gspca_dev->urb[0]->pipe);

                /* start the cam */
                ret = gspca_dev->sd_desc->start(gspca_dev);
                if (ret < 0) {
                        destroy_urbs(gspca_dev);
                        goto out;
                }
                v4l2_ctrl_handler_setup(gspca_dev->vdev.ctrl_handler);
                gspca_dev->streaming = true;

                /* some bulk transfers are started by the subdriver */
                if (gspca_dev->cam.bulk && gspca_dev->cam.bulk_nurbs == 0)
                        break;

                /* submit the URBs */
                for (n = 0; n < MAX_NURBS; n++) {
                        urb = gspca_dev->urb[n];
                        if (urb == NULL)
                                break;
                        ret = usb_submit_urb(urb, GFP_KERNEL);
                        if (ret < 0)
                                break;
                }
                if (ret >= 0)
                        break;                  /* transfer is started */

                /* something when wrong
                 * stop the webcam and free the transfer resources */
                gspca_stream_off(gspca_dev);
                if (ret != -ENOSPC) {
                        pr_err("usb_submit_urb alt %d err %d\n",
                               gspca_dev->alt, ret);
                        goto out;
                }

                /* the bandwidth is not wide enough
                 * negotiate or try a lower alternate setting */
retry:
                gspca_err(gspca_dev, "alt %d - bandwidth not wide enough, trying again\n",
                          alt);
                msleep(20);     /* wait for kill complete */
                if (gspca_dev->sd_desc->isoc_nego) {
                        ret = gspca_dev->sd_desc->isoc_nego(gspca_dev);
                        if (ret < 0)
                                goto out;
                } else {
                        if (alt_idx <= 0) {
                                pr_err("no transfer endpoint found\n");
                                ret = -EIO;
                                goto out;
                        }
                        gspca_dev->alt = ep_tb[--alt_idx].alt;
                }
        }
out:
        gspca_input_create_urb(gspca_dev);
        return ret;
}

static void gspca_set_default_mode(struct gspca_dev *gspca_dev)
{
        int i;

        i = gspca_dev->cam.nmodes - 1;  /* take the highest mode */
        gspca_dev->curr_mode = i;
        gspca_dev->pixfmt = gspca_dev->cam.cam_mode[i];

        /* does nothing if ctrl_handler == NULL */
        v4l2_ctrl_handler_setup(gspca_dev->vdev.ctrl_handler);
}

static int wxh_to_mode(struct gspca_dev *gspca_dev,
                        int width, int height, u32 pixelformat)
{
        int i;

        for (i = 0; i < gspca_dev->cam.nmodes; i++) {
                if (width == gspca_dev->cam.cam_mode[i].width
                    && height == gspca_dev->cam.cam_mode[i].height
                    && pixelformat == gspca_dev->cam.cam_mode[i].pixelformat)
                        return i;
        }
        return -EINVAL;
}

static int wxh_to_nearest_mode(struct gspca_dev *gspca_dev,
                        int width, int height, u32 pixelformat)
{
        int i;

        for (i = gspca_dev->cam.nmodes; --i >= 0; ) {
                if (width >= gspca_dev->cam.cam_mode[i].width
                    && height >= gspca_dev->cam.cam_mode[i].height
                    && pixelformat == gspca_dev->cam.cam_mode[i].pixelformat)
                        return i;
        }
        for (i = gspca_dev->cam.nmodes; --i > 0; ) {
                if (width >= gspca_dev->cam.cam_mode[i].width
                    && height >= gspca_dev->cam.cam_mode[i].height)
                        break;
        }
        return i;
}

/*
 * search a mode with the right pixel format
 */
static int gspca_get_mode(struct gspca_dev *gspca_dev,
                        int mode,
                        int pixfmt)
{
        int modeU, modeD;

        modeU = modeD = mode;
        while ((modeU < gspca_dev->cam.nmodes) || modeD >= 0) {
                if (--modeD >= 0) {
                        if (gspca_dev->cam.cam_mode[modeD].pixelformat
                                                                == pixfmt)
                                return modeD;
                }
                if (++modeU < gspca_dev->cam.nmodes) {
                        if (gspca_dev->cam.cam_mode[modeU].pixelformat
                                                                == pixfmt)
                                return modeU;
                }
        }
        return -EINVAL;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int vidioc_g_chip_info(struct file *file, void *priv,
                                struct v4l2_dbg_chip_info *chip)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        gspca_dev->usb_err = 0;
        if (gspca_dev->sd_desc->get_chip_info)
                return gspca_dev->sd_desc->get_chip_info(gspca_dev, chip);
        return chip->match.addr ? -EINVAL : 0;
}

static int vidioc_g_register(struct file *file, void *priv,
                struct v4l2_dbg_register *reg)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        gspca_dev->usb_err = 0;
        return gspca_dev->sd_desc->get_register(gspca_dev, reg);
}

static int vidioc_s_register(struct file *file, void *priv,
                const struct v4l2_dbg_register *reg)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        gspca_dev->usb_err = 0;
        return gspca_dev->sd_desc->set_register(gspca_dev, reg);
}
#endif

static int vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
                                struct v4l2_fmtdesc *fmtdesc)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);
        int i, j, index;
        __u32 fmt_tb[8];

        /* give an index to each format */
        index = 0;
        for (i = gspca_dev->cam.nmodes; --i >= 0; ) {
                fmt_tb[index] = gspca_dev->cam.cam_mode[i].pixelformat;
                j = 0;
                for (;;) {
                        if (fmt_tb[j] == fmt_tb[index])
                                break;
                        j++;
                }
                if (j == index) {
                        if (fmtdesc->index == index)
                                break;          /* new format */
                        index++;
                        if (index >= ARRAY_SIZE(fmt_tb))
                                return -EINVAL;
                }
        }
        if (i < 0)
                return -EINVAL;         /* no more format */

        fmtdesc->pixelformat = fmt_tb[index];
        return 0;
}

static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
                                struct v4l2_format *fmt)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);
        u32 fmt_priv = fmt->fmt.pix.priv;

        fmt->fmt.pix = gspca_dev->pixfmt;
        /* some drivers use priv internally, so keep the original value */
        fmt->fmt.pix.priv = fmt_priv;
        return 0;
}

static int try_fmt_vid_cap(struct gspca_dev *gspca_dev,
                        struct v4l2_format *fmt)
{
        int w, h, mode, mode2;

        w = fmt->fmt.pix.width;
        h = fmt->fmt.pix.height;

        PDEBUG_MODE(gspca_dev, D_CONF, "try fmt cap",
                    fmt->fmt.pix.pixelformat, w, h);

        /* search the nearest mode for width and height */
        mode = wxh_to_nearest_mode(gspca_dev, w, h, fmt->fmt.pix.pixelformat);

        /* OK if right palette */
        if (gspca_dev->cam.cam_mode[mode].pixelformat
                                                != fmt->fmt.pix.pixelformat) {

                /* else, search the closest mode with the same pixel format */
                mode2 = gspca_get_mode(gspca_dev, mode,
                                        fmt->fmt.pix.pixelformat);
                if (mode2 >= 0)
                        mode = mode2;
        }
        fmt->fmt.pix = gspca_dev->cam.cam_mode[mode];
        if (gspca_dev->sd_desc->try_fmt) {
                /* pass original resolution to subdriver try_fmt */
                fmt->fmt.pix.width = w;
                fmt->fmt.pix.height = h;
                gspca_dev->sd_desc->try_fmt(gspca_dev, fmt);
        }
        return mode;                    /* used when s_fmt */
}

static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
                                  struct v4l2_format *fmt)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);
        u32 fmt_priv = fmt->fmt.pix.priv;

        if (try_fmt_vid_cap(gspca_dev, fmt) < 0)
                return -EINVAL;
        /* some drivers use priv internally, so keep the original value */
        fmt->fmt.pix.priv = fmt_priv;
        return 0;
}

static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
                                struct v4l2_format *fmt)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);
        u32 fmt_priv = fmt->fmt.pix.priv;
        int mode;

        if (vb2_is_busy(&gspca_dev->queue))
                return -EBUSY;

        mode = try_fmt_vid_cap(gspca_dev, fmt);
        if (mode < 0)
                return -EINVAL;

        gspca_dev->curr_mode = mode;
        if (gspca_dev->sd_desc->try_fmt)
                /* subdriver try_fmt can modify format parameters */
                gspca_dev->pixfmt = fmt->fmt.pix;
        else
                gspca_dev->pixfmt = gspca_dev->cam.cam_mode[mode];
        /* some drivers use priv internally, so keep the original value */
        fmt->fmt.pix.priv = fmt_priv;
        return 0;
}

static int vidioc_enum_framesizes(struct file *file, void *priv,
                                  struct v4l2_frmsizeenum *fsize)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);
        int i;
        __u32 index = 0;

        if (gspca_dev->sd_desc->enum_framesizes)
                return gspca_dev->sd_desc->enum_framesizes(gspca_dev, fsize);

        for (i = 0; i < gspca_dev->cam.nmodes; i++) {
                if (fsize->pixel_format !=
                                gspca_dev->cam.cam_mode[i].pixelformat)
                        continue;

                if (fsize->index == index) {
                        fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
                        fsize->discrete.width =
                                gspca_dev->cam.cam_mode[i].width;
                        fsize->discrete.height =
                                gspca_dev->cam.cam_mode[i].height;
                        return 0;
                }
                index++;
        }

        return -EINVAL;
}

static int vidioc_enum_frameintervals(struct file *filp, void *priv,
                                      struct v4l2_frmivalenum *fival)
{
        struct gspca_dev *gspca_dev = video_drvdata(filp);
        int mode;
        __u32 i;

        mode = wxh_to_mode(gspca_dev, fival->width, fival->height,
                           fival->pixel_format);
        if (mode < 0)
                return -EINVAL;

        if (gspca_dev->cam.mode_framerates == NULL ||
                        gspca_dev->cam.mode_framerates[mode].nrates == 0)
                return -EINVAL;

        if (fival->pixel_format !=
                        gspca_dev->cam.cam_mode[mode].pixelformat)
                return -EINVAL;

        for (i = 0; i < gspca_dev->cam.mode_framerates[mode].nrates; i++) {
                if (fival->index == i) {
                        fival->type = V4L2_FRMIVAL_TYPE_DISCRETE;
                        fival->discrete.numerator = 1;
                        fival->discrete.denominator =
                                gspca_dev->cam.mode_framerates[mode].rates[i];
                        return 0;
                }
        }

        return -EINVAL;
}

static void gspca_release(struct v4l2_device *v4l2_device)
{
        struct gspca_dev *gspca_dev =
                container_of(v4l2_device, struct gspca_dev, v4l2_dev);

        v4l2_ctrl_handler_free(gspca_dev->vdev.ctrl_handler);
        v4l2_device_unregister(&gspca_dev->v4l2_dev);
        kfree(gspca_dev->usb_buf);
        kfree(gspca_dev);
}

static int vidioc_querycap(struct file *file, void  *priv,
                           struct v4l2_capability *cap)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        strscpy((char *)cap->driver, gspca_dev->sd_desc->name,
                sizeof(cap->driver));
        if (gspca_dev->dev->product != NULL) {
                strscpy((char *)cap->card, gspca_dev->dev->product,
                        sizeof(cap->card));
        } else {
                snprintf((char *) cap->card, sizeof cap->card,
                        "USB Camera (%04x:%04x)",
                        le16_to_cpu(gspca_dev->dev->descriptor.idVendor),
                        le16_to_cpu(gspca_dev->dev->descriptor.idProduct));
        }
        usb_make_path(gspca_dev->dev, (char *) cap->bus_info,
                        sizeof(cap->bus_info));
        return 0;
}

static int vidioc_enum_input(struct file *file, void *priv,
                                struct v4l2_input *input)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        if (input->index != 0)
                return -EINVAL;
        input->type = V4L2_INPUT_TYPE_CAMERA;
        input->status = gspca_dev->cam.input_flags;
        strscpy(input->name, gspca_dev->sd_desc->name,
                sizeof input->name);
        return 0;
}

static int vidioc_g_input(struct file *file, void *priv, unsigned int *i)
{
        *i = 0;
        return 0;
}

static int vidioc_s_input(struct file *file, void *priv, unsigned int i)
{
        if (i > 0)
                return -EINVAL;
        return 0;
}

static int vidioc_g_jpegcomp(struct file *file, void *priv,
                        struct v4l2_jpegcompression *jpegcomp)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        gspca_dev->usb_err = 0;
        return gspca_dev->sd_desc->get_jcomp(gspca_dev, jpegcomp);
}

static int vidioc_s_jpegcomp(struct file *file, void *priv,
                        const struct v4l2_jpegcompression *jpegcomp)
{
        struct gspca_dev *gspca_dev = video_drvdata(file);

        gspca_dev->usb_err = 0;
        return gspca_dev->sd_desc->set_jcomp(gspca_dev, jpegcomp);
}

static int vidioc_g_parm(struct file *filp, void *priv,
                        struct v4l2_streamparm *parm)
{
        struct gspca_dev *gspca_dev = video_drvdata(filp);

        parm->parm.capture.readbuffers = gspca_dev->queue.min_queued_buffers;

        if (!gspca_dev->sd_desc->get_streamparm)
                return 0;

        parm->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
        gspca_dev->usb_err = 0;
        gspca_dev->sd_desc->get_streamparm(gspca_dev, parm);
        return gspca_dev->usb_err;
}

static int vidioc_s_parm(struct file *filp, void *priv,
                        struct v4l2_streamparm *parm)
{
        struct gspca_dev *gspca_dev = video_drvdata(filp);

        parm->parm.capture.readbuffers = gspca_dev->queue.min_queued_buffers;

        if (!gspca_dev->sd_desc->set_streamparm) {
                parm->parm.capture.capability = 0;
                return 0;
        }

        parm->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
        gspca_dev->usb_err = 0;
        gspca_dev->sd_desc->set_streamparm(gspca_dev, parm);
        return gspca_dev->usb_err;
}

static int gspca_queue_setup(struct vb2_queue *vq,
                             unsigned int *nbuffers, unsigned int *nplanes,
                             unsigned int sizes[], struct device *alloc_devs[])
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vq);
        unsigned int size = PAGE_ALIGN(gspca_dev->pixfmt.sizeimage);

        if (*nplanes)
                return sizes[0] < size ? -EINVAL : 0;
        *nplanes = 1;
        sizes[0] = size;
        return 0;
}

static int gspca_buffer_prepare(struct vb2_buffer *vb)
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vb->vb2_queue);
        unsigned long size = PAGE_ALIGN(gspca_dev->pixfmt.sizeimage);

        if (vb2_plane_size(vb, 0) < size) {
                gspca_err(gspca_dev, "buffer too small (%lu < %lu)\n",
                         vb2_plane_size(vb, 0), size);
                return -EINVAL;
        }
        return 0;
}

static void gspca_buffer_finish(struct vb2_buffer *vb)
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vb->vb2_queue);

        if (!gspca_dev->sd_desc->dq_callback)
                return;

        gspca_dev->usb_err = 0;
        if (gspca_dev->present)
                gspca_dev->sd_desc->dq_callback(gspca_dev);
}

static void gspca_buffer_queue(struct vb2_buffer *vb)
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vb->vb2_queue);
        struct gspca_buffer *buf = to_gspca_buffer(vb);
        unsigned long flags;

        spin_lock_irqsave(&gspca_dev->qlock, flags);
        list_add_tail(&buf->list, &gspca_dev->buf_list);
        spin_unlock_irqrestore(&gspca_dev->qlock, flags);
}

static void gspca_return_all_buffers(struct gspca_dev *gspca_dev,
                                     enum vb2_buffer_state state)
{
        struct gspca_buffer *buf, *node;
        unsigned long flags;

        spin_lock_irqsave(&gspca_dev->qlock, flags);
        list_for_each_entry_safe(buf, node, &gspca_dev->buf_list, list) {
                vb2_buffer_done(&buf->vb.vb2_buf, state);
                list_del(&buf->list);
        }
        spin_unlock_irqrestore(&gspca_dev->qlock, flags);
}

static int gspca_start_streaming(struct vb2_queue *vq, unsigned int count)
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vq);
        int ret;

        gspca_dev->sequence = 0;

        ret = gspca_init_transfer(gspca_dev);
        if (ret)
                gspca_return_all_buffers(gspca_dev, VB2_BUF_STATE_QUEUED);
        return ret;
}

static void gspca_stop_streaming(struct vb2_queue *vq)
{
        struct gspca_dev *gspca_dev = vb2_get_drv_priv(vq);

        gspca_stream_off(gspca_dev);

        /* Release all active buffers */
        gspca_return_all_buffers(gspca_dev, VB2_BUF_STATE_ERROR);
}

static const struct vb2_ops gspca_qops = {
        .queue_setup            = gspca_queue_setup,
        .buf_prepare            = gspca_buffer_prepare,
        .buf_finish             = gspca_buffer_finish,
        .buf_queue              = gspca_buffer_queue,
        .start_streaming        = gspca_start_streaming,
        .stop_streaming         = gspca_stop_streaming,
};

static const struct v4l2_file_operations dev_fops = {
        .owner = THIS_MODULE,
        .open = v4l2_fh_open,
        .release = vb2_fop_release,
        .unlocked_ioctl = video_ioctl2,
        .read = vb2_fop_read,
        .mmap = vb2_fop_mmap,
        .poll = vb2_fop_poll,
};

static const struct v4l2_ioctl_ops dev_ioctl_ops = {
        .vidioc_querycap        = vidioc_querycap,
        .vidioc_enum_fmt_vid_cap = vidioc_enum_fmt_vid_cap,
        .vidioc_try_fmt_vid_cap = vidioc_try_fmt_vid_cap,
        .vidioc_g_fmt_vid_cap   = vidioc_g_fmt_vid_cap,
        .vidioc_s_fmt_vid_cap   = vidioc_s_fmt_vid_cap,
        .vidioc_enum_input      = vidioc_enum_input,
        .vidioc_g_input         = vidioc_g_input,
        .vidioc_s_input         = vidioc_s_input,
        .vidioc_g_jpegcomp      = vidioc_g_jpegcomp,
        .vidioc_s_jpegcomp      = vidioc_s_jpegcomp,
        .vidioc_g_parm          = vidioc_g_parm,
        .vidioc_s_parm          = vidioc_s_parm,
        .vidioc_enum_framesizes = vidioc_enum_framesizes,
        .vidioc_enum_frameintervals = vidioc_enum_frameintervals,

        .vidioc_reqbufs         = vb2_ioctl_reqbufs,
        .vidioc_create_bufs     = vb2_ioctl_create_bufs,
        .vidioc_querybuf        = vb2_ioctl_querybuf,
        .vidioc_qbuf            = vb2_ioctl_qbuf,
        .vidioc_dqbuf           = vb2_ioctl_dqbuf,
        .vidioc_expbuf          = vb2_ioctl_expbuf,
        .vidioc_streamon        = vb2_ioctl_streamon,
        .vidioc_streamoff       = vb2_ioctl_streamoff,

#ifdef CONFIG_VIDEO_ADV_DEBUG
        .vidioc_g_chip_info     = vidioc_g_chip_info,
        .vidioc_g_register      = vidioc_g_register,
        .vidioc_s_register      = vidioc_s_register,
#endif
        .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
        .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
};

static const struct video_device gspca_template = {
        .name = "gspca main driver",
        .fops = &dev_fops,
        .ioctl_ops = &dev_ioctl_ops,
        .release = video_device_release_empty, /* We use v4l2_dev.release */
};

/*
 * probe and create a new gspca device
 *
 * This function must be called by the sub-driver when it is
 * called for probing a new device.
 */
int gspca_dev_probe2(struct usb_interface *intf,
                const struct usb_device_id *id,
                const struct sd_desc *sd_desc,
                int dev_size,
                struct module *module)
{
        struct gspca_dev *gspca_dev;
        struct usb_device *dev = interface_to_usbdev(intf);
        struct vb2_queue *q;
        int ret;

        pr_info("%s-" GSPCA_VERSION " probing %04x:%04x\n",
                sd_desc->name, id->idVendor, id->idProduct);

        /* create the device */
        if (dev_size < sizeof *gspca_dev)
                dev_size = sizeof *gspca_dev;
        gspca_dev = kzalloc(dev_size, GFP_KERNEL);
        if (!gspca_dev) {
                pr_err("couldn't kzalloc gspca struct\n");
                return -ENOMEM;
        }
        gspca_dev->usb_buf = kzalloc(USB_BUF_SZ, GFP_KERNEL);
        if (!gspca_dev->usb_buf) {
                pr_err("out of memory\n");
                ret = -ENOMEM;
                goto out;
        }
        gspca_dev->dev = dev;
        gspca_dev->iface = intf->cur_altsetting->desc.bInterfaceNumber;
        gspca_dev->xfer_ep = -1;

        /* check if any audio device */
        if (dev->actconfig->desc.bNumInterfaces != 1) {
                int i;
                struct usb_interface *intf2;

                for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
                        intf2 = dev->actconfig->interface[i];
                        if (intf2 != NULL
                         && intf2->altsetting != NULL
                         && intf2->altsetting->desc.bInterfaceClass ==
                                         USB_CLASS_AUDIO) {
                                gspca_dev->audio = 1;
                                break;
                        }
                }
        }

        gspca_dev->v4l2_dev.release = gspca_release;
        ret = v4l2_device_register(&intf->dev, &gspca_dev->v4l2_dev);
        if (ret)
                goto out;
        gspca_dev->present = true;
        gspca_dev->sd_desc = sd_desc;
        gspca_dev->empty_packet = -1;   /* don't check the empty packets */
        gspca_dev->vdev = gspca_template;
        gspca_dev->vdev.v4l2_dev = &gspca_dev->v4l2_dev;
        gspca_dev->vdev.device_caps = V4L2_CAP_VIDEO_CAPTURE |
                                      V4L2_CAP_STREAMING | V4L2_CAP_READWRITE;
        video_set_drvdata(&gspca_dev->vdev, gspca_dev);
        gspca_dev->module = module;

        mutex_init(&gspca_dev->usb_lock);
        gspca_dev->vdev.lock = &gspca_dev->usb_lock;
        init_waitqueue_head(&gspca_dev->wq);

        /* Initialize the vb2 queue */
        q = &gspca_dev->queue;
        q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF | VB2_READ;
        q->drv_priv = gspca_dev;
        q->buf_struct_size = sizeof(struct gspca_buffer);
        q->ops = &gspca_qops;
        q->mem_ops = &vb2_vmalloc_memops;
        q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
        q->min_queued_buffers = 2;
        q->lock = &gspca_dev->usb_lock;
        ret = vb2_queue_init(q);
        if (ret)
                goto out;
        gspca_dev->vdev.queue = q;

        INIT_LIST_HEAD(&gspca_dev->buf_list);
        spin_lock_init(&gspca_dev->qlock);

        /* configure the subdriver and initialize the USB device */
        ret = sd_desc->config(gspca_dev, id);
        if (ret < 0)
                goto out;
        ret = sd_desc->init(gspca_dev);
        if (ret < 0)
                goto out;
        if (sd_desc->init_controls)
                ret = sd_desc->init_controls(gspca_dev);
        if (ret < 0)
                goto out;
        gspca_set_default_mode(gspca_dev);

        ret = gspca_input_connect(gspca_dev);
        if (ret)
                goto out;

#ifdef CONFIG_VIDEO_ADV_DEBUG
        if (!gspca_dev->sd_desc->get_register)
                v4l2_disable_ioctl(&gspca_dev->vdev, VIDIOC_DBG_G_REGISTER);
        if (!gspca_dev->sd_desc->set_register)
                v4l2_disable_ioctl(&gspca_dev->vdev, VIDIOC_DBG_S_REGISTER);
#endif
        if (!gspca_dev->sd_desc->get_jcomp)
                v4l2_disable_ioctl(&gspca_dev->vdev, VIDIOC_G_JPEGCOMP);
        if (!gspca_dev->sd_desc->set_jcomp)
                v4l2_disable_ioctl(&gspca_dev->vdev, VIDIOC_S_JPEGCOMP);

        /* init video stuff */
        ret = video_register_device(&gspca_dev->vdev,
                                  VFL_TYPE_VIDEO,
                                  -1);
        if (ret < 0) {
                pr_err("video_register_device err %d\n", ret);
                goto out;
        }

        usb_set_intfdata(intf, gspca_dev);
        gspca_dbg(gspca_dev, D_PROBE, "%s created\n",
                  video_device_node_name(&gspca_dev->vdev));

        gspca_input_create_urb(gspca_dev);

        return 0;
out:
#if IS_ENABLED(CONFIG_INPUT)
        if (gspca_dev->input_dev)
                input_unregister_device(gspca_dev->input_dev);
#endif
        v4l2_ctrl_handler_free(gspca_dev->vdev.ctrl_handler);
        v4l2_device_unregister(&gspca_dev->v4l2_dev);
        if (sd_desc->probe_error)
                sd_desc->probe_error(gspca_dev);
        kfree(gspca_dev->usb_buf);
        kfree(gspca_dev);
        return ret;
}
EXPORT_SYMBOL(gspca_dev_probe2);

/* same function as the previous one, but check the interface */
int gspca_dev_probe(struct usb_interface *intf,
                const struct usb_device_id *id,
                const struct sd_desc *sd_desc,
                int dev_size,
                struct module *module)
{
        struct usb_device *dev = interface_to_usbdev(intf);

        /* we don't handle multi-config cameras */
        if (dev->descriptor.bNumConfigurations != 1) {
                pr_err("%04x:%04x too many config\n",
                       id->idVendor, id->idProduct);
                return -ENODEV;
        }

        /* the USB video interface must be the first one */
        if (dev->actconfig->desc.bNumInterfaces != 1
         && intf->cur_altsetting->desc.bInterfaceNumber != 0)
                return -ENODEV;

        return gspca_dev_probe2(intf, id, sd_desc, dev_size, module);
}
EXPORT_SYMBOL(gspca_dev_probe);

/*
 * USB disconnection
 *
 * This function must be called by the sub-driver
 * when the device disconnects, after the specific resources are freed.
 */
void gspca_disconnect(struct usb_interface *intf)
{
        struct gspca_dev *gspca_dev = usb_get_intfdata(intf);
#if IS_ENABLED(CONFIG_INPUT)
        struct input_dev *input_dev;
#endif

        gspca_dbg(gspca_dev, D_PROBE, "%s disconnect\n",
                  video_device_node_name(&gspca_dev->vdev));

        mutex_lock(&gspca_dev->usb_lock);
        gspca_dev->present = false;
        destroy_urbs(gspca_dev);
        gspca_input_destroy_urb(gspca_dev);

        vb2_queue_error(&gspca_dev->queue);

#if IS_ENABLED(CONFIG_INPUT)
        input_dev = gspca_dev->input_dev;
        if (input_dev) {
                gspca_dev->input_dev = NULL;
                input_unregister_device(input_dev);
        }
#endif

        v4l2_device_disconnect(&gspca_dev->v4l2_dev);
        video_unregister_device(&gspca_dev->vdev);

        mutex_unlock(&gspca_dev->usb_lock);

        /* (this will call gspca_release() immediately or on last close) */
        v4l2_device_put(&gspca_dev->v4l2_dev);
}
EXPORT_SYMBOL(gspca_disconnect);

#ifdef CONFIG_PM
int gspca_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct gspca_dev *gspca_dev = usb_get_intfdata(intf);

        gspca_input_destroy_urb(gspca_dev);

        if (!vb2_start_streaming_called(&gspca_dev->queue))
                return 0;

        mutex_lock(&gspca_dev->usb_lock);
        gspca_dev->frozen = 1;          /* avoid urb error messages */
        gspca_dev->usb_err = 0;
        if (gspca_dev->sd_desc->stopN)
                gspca_dev->sd_desc->stopN(gspca_dev);
        destroy_urbs(gspca_dev);
        gspca_set_alt0(gspca_dev);
        if (gspca_dev->sd_desc->stop0)
                gspca_dev->sd_desc->stop0(gspca_dev);
        mutex_unlock(&gspca_dev->usb_lock);

        return 0;
}
EXPORT_SYMBOL(gspca_suspend);

int gspca_resume(struct usb_interface *intf)
{
        struct gspca_dev *gspca_dev = usb_get_intfdata(intf);
        int streaming, ret = 0;

        mutex_lock(&gspca_dev->usb_lock);
        gspca_dev->frozen = 0;
        gspca_dev->usb_err = 0;
        gspca_dev->sd_desc->init(gspca_dev);
        /*
         * Most subdrivers send all ctrl values on sd_start and thus
         * only write to the device registers on s_ctrl when streaming ->
         * Clear streaming to avoid setting all ctrls twice.
         */
        streaming = vb2_start_streaming_called(&gspca_dev->queue);
        if (streaming)
                ret = gspca_init_transfer(gspca_dev);
        else
                gspca_input_create_urb(gspca_dev);
        mutex_unlock(&gspca_dev->usb_lock);

        return ret;
}
EXPORT_SYMBOL(gspca_resume);
#endif

/* -- module insert / remove -- */
static int __init gspca_init(void)
{
        pr_info("v" GSPCA_VERSION " registered\n");
        return 0;
}
static void __exit gspca_exit(void)
{
}

module_init(gspca_init);
module_exit(gspca_exit);

module_param_named(debug, gspca_debug, int, 0644);
MODULE_PARM_DESC(debug,
                "1:probe 2:config 3:stream 4:frame 5:packet 6:usbi 7:usbo");