/*
 * USB ViCam WebCam driver
 * Copyright (c) 2002 Joe Burks (jburks@wavicle.org),
 *                    Christopher L Cheney (ccheney@cheney.cx),
 *                    Pavel Machek (pavel@suse.cz),
 *                    John Tyner (jtyner@cs.ucr.edu),
 *                    Monroe Williams (monroe@pobox.com)
 *
 * Supports 3COM HomeConnect PC Digital WebCam
 * Supports Compro PS39U WebCam
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * This source code is based heavily on the CPiA webcam driver which was
 * written by Peter Pregler, Scott J. Bertin and Johannes Erdfelt
 *
 * Portions of this code were also copied from usbvideo.c
 *
 * Special thanks to the whole team at Sourceforge for help making
 * this driver become a reality.  Notably:
 * Andy Armstrong who reverse engineered the color encoding and
 * Pavel Machek and Chris Cheney who worked on reverse engineering the
 *    camera controls and wrote the first generation driver.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/videodev.h>
#include <linux/usb.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/firmware.h>
#include <linux/ihex.h>
#include "usbvideo.h"

// #define VICAM_DEBUG

#ifdef VICAM_DEBUG
#define ADBG(lineno,fmt,args...) printk(fmt, jiffies, __func__, lineno, ##args)
#define DBG(fmt,args...) ADBG((__LINE__),KERN_DEBUG __FILE__"(%ld):%s (%d):"fmt,##args)
#else
#define DBG(fmn,args...) do {} while(0)
#endif

#define DRIVER_AUTHOR           "Joe Burks, jburks@wavicle.org"
#define DRIVER_DESC             "ViCam WebCam Driver"

/* Define these values to match your device */
#define USB_VICAM_VENDOR_ID     0x04c1
#define USB_VICAM_PRODUCT_ID    0x009d
#define USB_COMPRO_VENDOR_ID    0x0602
#define USB_COMPRO_PRODUCT_ID   0x1001

#define VICAM_BYTES_PER_PIXEL   3
#define VICAM_MAX_READ_SIZE     (512*242+128)
#define VICAM_MAX_FRAME_SIZE    (VICAM_BYTES_PER_PIXEL*320*240)
#define VICAM_FRAMES            2

#define VICAM_HEADER_SIZE       64

/* rvmalloc / rvfree copied from usbvideo.c
 *
 * Not sure why these are not yet non-statics which I can reference through
 * usbvideo.h the same as it is in 2.4.20.  I bet this will get fixed sometime
 * in the future.
 *
*/
static void *rvmalloc(unsigned long size)
{
        void *mem;
        unsigned long adr;

        size = PAGE_ALIGN(size);
        mem = vmalloc_32(size);
        if (!mem)
                return NULL;

        memset(mem, 0, size); /* Clear the ram out, no junk to the user */
        adr = (unsigned long) mem;
        while (size > 0) {
                SetPageReserved(vmalloc_to_page((void *)adr));
                adr += PAGE_SIZE;
                size -= PAGE_SIZE;
        }

        return mem;
}

static void rvfree(void *mem, unsigned long size)
{
        unsigned long adr;

        if (!mem)
                return;

        adr = (unsigned long) mem;
        while ((long) size > 0) {
                ClearPageReserved(vmalloc_to_page((void *)adr));
                adr += PAGE_SIZE;
                size -= PAGE_SIZE;
        }
        vfree(mem);
}

struct vicam_camera {
        u16 shutter_speed;      // capture shutter speed
        u16 gain;               // capture gain

        u8 *raw_image;          // raw data captured from the camera
        u8 *framebuf;           // processed data in RGB24 format
        u8 *cntrlbuf;           // area used to send control msgs

        struct video_device vdev;       // v4l video device
        struct usb_device *udev;        // usb device

        /* guard against simultaneous accesses to the camera */
        struct mutex cam_lock;

        int is_initialized;
        u8 open_count;
        u8 bulkEndpoint;
        int needsDummyRead;
};

static int vicam_probe( struct usb_interface *intf, const struct usb_device_id *id);
static void vicam_disconnect(struct usb_interface *intf);
static void read_frame(struct vicam_camera *cam, int framenum);
static void vicam_decode_color(const u8 *, u8 *);

static int __send_control_msg(struct vicam_camera *cam,
                              u8 request,
                              u16 value,
                              u16 index,
                              unsigned char *cp,
                              u16 size)
{
        int status;

        /* cp must be memory that has been allocated by kmalloc */

        status = usb_control_msg(cam->udev,
                                 usb_sndctrlpipe(cam->udev, 0),
                                 request,
                                 USB_DIR_OUT | USB_TYPE_VENDOR |
                                 USB_RECIP_DEVICE, value, index,
                                 cp, size, 1000);

        status = min(status, 0);

        if (status < 0) {
                printk(KERN_INFO "Failed sending control message, error %d.\n",
                       status);
        }

        return status;
}

static int send_control_msg(struct vicam_camera *cam,
                            u8 request,
                            u16 value,
                            u16 index,
                            unsigned char *cp,
                            u16 size)
{
        int status = -ENODEV;
        mutex_lock(&cam->cam_lock);
        if (cam->udev) {
                status = __send_control_msg(cam, request, value,
                                            index, cp, size);
        }
        mutex_unlock(&cam->cam_lock);
        return status;
}
static int
initialize_camera(struct vicam_camera *cam)
{
        int err;
        const struct ihex_binrec *rec;
        const struct firmware *uninitialized_var(fw);

        err = request_ihex_firmware(&fw, "vicam/firmware.fw", &cam->udev->dev);
        if (err) {
                printk(KERN_ERR "Failed to load \"vicam/firmware.fw\": %d\n",
                       err);
                return err;
        }

        for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
                memcpy(cam->cntrlbuf, rec->data, be16_to_cpu(rec->len));

                err = send_control_msg(cam, 0xff, 0, 0,
                                       cam->cntrlbuf, be16_to_cpu(rec->len));
                if (err)
                        break;
        }

        release_firmware(fw);

        return err;
}

static int
set_camera_power(struct vicam_camera *cam, int state)
{
        int status;

        if ((status = send_control_msg(cam, 0x50, state, 0, NULL, 0)) < 0)
                return status;

        if (state) {
                send_control_msg(cam, 0x55, 1, 0, NULL, 0);
        }

        return 0;
}

static long
vicam_ioctl(struct file *file, unsigned int ioctlnr, unsigned long arg)
{
        void __user *user_arg = (void __user *)arg;
        struct vicam_camera *cam = file->private_data;
        long retval = 0;

        if (!cam)
                return -ENODEV;

        switch (ioctlnr) {
                /* query capabilities */
        case VIDIOCGCAP:
                {
                        struct video_capability b;

                        DBG("VIDIOCGCAP\n");
                        memset(&b, 0, sizeof(b));
                        strcpy(b.name, "ViCam-based Camera");
                        b.type = VID_TYPE_CAPTURE;
                        b.channels = 1;
                        b.audios = 0;
                        b.maxwidth = 320;       /* VIDEOSIZE_CIF */
                        b.maxheight = 240;
                        b.minwidth = 320;       /* VIDEOSIZE_48_48 */
                        b.minheight = 240;

                        if (copy_to_user(user_arg, &b, sizeof(b)))
                                retval = -EFAULT;

                        break;
                }
                /* get/set video source - we are a camera and nothing else */
        case VIDIOCGCHAN:
                {
                        struct video_channel v;

                        DBG("VIDIOCGCHAN\n");
                        if (copy_from_user(&v, user_arg, sizeof(v))) {
                                retval = -EFAULT;
                                break;
                        }
                        if (v.channel != 0) {
                                retval = -EINVAL;
                                break;
                        }

                        v.channel = 0;
                        strcpy(v.name, "Camera");
                        v.tuners = 0;
                        v.flags = 0;
                        v.type = VIDEO_TYPE_CAMERA;
                        v.norm = 0;

                        if (copy_to_user(user_arg, &v, sizeof(v)))
                                retval = -EFAULT;
                        break;
                }

        case VIDIOCSCHAN:
                {
                        int v;

                        if (copy_from_user(&v, user_arg, sizeof(v)))
                                retval = -EFAULT;
                        DBG("VIDIOCSCHAN %d\n", v);

                        if (retval == 0 && v != 0)
                                retval = -EINVAL;

                        break;
                }

                /* image properties */
        case VIDIOCGPICT:
                {
                        struct video_picture vp;
                        DBG("VIDIOCGPICT\n");
                        memset(&vp, 0, sizeof (struct video_picture));
                        vp.brightness = cam->gain << 8;
                        vp.depth = 24;
                        vp.palette = VIDEO_PALETTE_RGB24;
                        if (copy_to_user(user_arg, &vp, sizeof (struct video_picture)))
                                retval = -EFAULT;
                        break;
                }

        case VIDIOCSPICT:
                {
                        struct video_picture vp;

                        if (copy_from_user(&vp, user_arg, sizeof(vp))) {
                                retval = -EFAULT;
                                break;
                        }

                        DBG("VIDIOCSPICT depth = %d, pal = %d\n", vp.depth,
                            vp.palette);

                        cam->gain = vp.brightness >> 8;

                        if (vp.depth != 24
                            || vp.palette != VIDEO_PALETTE_RGB24)
                                retval = -EINVAL;

                        break;
                }

                /* get/set capture window */
        case VIDIOCGWIN:
                {
                        struct video_window vw;
                        vw.x = 0;
                        vw.y = 0;
                        vw.width = 320;
                        vw.height = 240;
                        vw.chromakey = 0;
                        vw.flags = 0;
                        vw.clips = NULL;
                        vw.clipcount = 0;

                        DBG("VIDIOCGWIN\n");

                        if (copy_to_user(user_arg, (void *)&vw, sizeof(vw)))
                                retval = -EFAULT;

                        // I'm not sure what the deal with a capture window is, it is very poorly described
                        // in the doc.  So I won't support it now.
                        break;
                }

        case VIDIOCSWIN:
                {

                        struct video_window vw;

                        if (copy_from_user(&vw, user_arg, sizeof(vw))) {
                                retval = -EFAULT;
                                break;
                        }

                        DBG("VIDIOCSWIN %d x %d\n", vw.width, vw.height);

                        if ( vw.width != 320 || vw.height != 240 )
                                retval = -EFAULT;

                        break;
                }

                /* mmap interface */
        case VIDIOCGMBUF:
                {
                        struct video_mbuf vm;
                        int i;

                        DBG("VIDIOCGMBUF\n");
                        memset(&vm, 0, sizeof (vm));
                        vm.size =
                            VICAM_MAX_FRAME_SIZE * VICAM_FRAMES;
                        vm.frames = VICAM_FRAMES;
                        for (i = 0; i < VICAM_FRAMES; i++)
                                vm.offsets[i] = VICAM_MAX_FRAME_SIZE * i;

                        if (copy_to_user(user_arg, (void *)&vm, sizeof(vm)))
                                retval = -EFAULT;

                        break;
                }

        case VIDIOCMCAPTURE:
                {
                        struct video_mmap vm;
                        // int video_size;

                        if (copy_from_user((void *)&vm, user_arg, sizeof(vm))) {
                                retval = -EFAULT;
                                break;
                        }

                        DBG("VIDIOCMCAPTURE frame=%d, height=%d, width=%d, format=%d.\n",vm.frame,vm.width,vm.height,vm.format);

                        if ( vm.frame >= VICAM_FRAMES || vm.format != VIDEO_PALETTE_RGB24 )
                                retval = -EINVAL;

                        // in theory right here we'd start the image capturing
                        // (fill in a bulk urb and submit it asynchronously)
                        //
                        // Instead we're going to do a total hack job for now and
                        // retrieve the frame in VIDIOCSYNC

                        break;
                }

        case VIDIOCSYNC:
                {
                        int frame;

                        if (copy_from_user((void *)&frame, user_arg, sizeof(int))) {
                                retval = -EFAULT;
                                break;
                        }
                        DBG("VIDIOCSYNC: %d\n", frame);

                        read_frame(cam, frame);
                        vicam_decode_color(cam->raw_image,
                                           cam->framebuf +
                                           frame * VICAM_MAX_FRAME_SIZE );

                        break;
                }

                /* pointless to implement overlay with this camera */
        case VIDIOCCAPTURE:
        case VIDIOCGFBUF:
        case VIDIOCSFBUF:
        case VIDIOCKEY:
                retval = -EINVAL;
                break;

                /* tuner interface - we have none */
        case VIDIOCGTUNER:
        case VIDIOCSTUNER:
        case VIDIOCGFREQ:
        case VIDIOCSFREQ:
                retval = -EINVAL;
                break;

                /* audio interface - we have none */
        case VIDIOCGAUDIO:
        case VIDIOCSAUDIO:
                retval = -EINVAL;
                break;
        default:
                retval = -ENOIOCTLCMD;
                break;
        }

        return retval;
}

static int
vicam_open(struct file *file)
{
        struct vicam_camera *cam = video_drvdata(file);

        DBG("open\n");

        if (!cam) {
                printk(KERN_ERR
                       "vicam video_device improperly initialized");
                return -EINVAL;
        }

        /* the videodev_lock held above us protects us from
         * simultaneous opens...for now. we probably shouldn't
         * rely on this fact forever.
         */

        lock_kernel();
        if (cam->open_count > 0) {
                printk(KERN_INFO
                       "vicam_open called on already opened camera");
                unlock_kernel();
                return -EBUSY;
        }

        cam->raw_image = kmalloc(VICAM_MAX_READ_SIZE, GFP_KERNEL);
        if (!cam->raw_image) {
                unlock_kernel();
                return -ENOMEM;
        }

        cam->framebuf = rvmalloc(VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
        if (!cam->framebuf) {
                kfree(cam->raw_image);
                unlock_kernel();
                return -ENOMEM;
        }

        cam->cntrlbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!cam->cntrlbuf) {
                kfree(cam->raw_image);
                rvfree(cam->framebuf, VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
                unlock_kernel();
                return -ENOMEM;
        }

        // First upload firmware, then turn the camera on

        if (!cam->is_initialized) {
                initialize_camera(cam);

                cam->is_initialized = 1;
        }

        set_camera_power(cam, 1);

        cam->needsDummyRead = 1;
        cam->open_count++;

        file->private_data = cam;
        unlock_kernel();

        return 0;
}

static int
vicam_close(struct file *file)
{
        struct vicam_camera *cam = file->private_data;
        int open_count;
        struct usb_device *udev;

        DBG("close\n");

        /* it's not the end of the world if
         * we fail to turn the camera off.
         */

        set_camera_power(cam, 0);

        kfree(cam->raw_image);
        rvfree(cam->framebuf, VICAM_MAX_FRAME_SIZE * VICAM_FRAMES);
        kfree(cam->cntrlbuf);

        mutex_lock(&cam->cam_lock);

        cam->open_count--;
        open_count = cam->open_count;
        udev = cam->udev;

        mutex_unlock(&cam->cam_lock);

        if (!open_count && !udev) {
                kfree(cam);
        }

        return 0;
}

static void vicam_decode_color(const u8 *data, u8 *rgb)
{
        /* vicam_decode_color - Convert from Vicam Y-Cr-Cb to RGB
         * Copyright (C) 2002 Monroe Williams (monroe@pobox.com)
         */

        int i, prevY, nextY;

        prevY = 512;
        nextY = 512;

        data += VICAM_HEADER_SIZE;

        for( i = 0; i < 240; i++, data += 512 ) {
                const int y = ( i * 242 ) / 240;

                int j, prevX, nextX;
                int Y, Cr, Cb;

                if ( y == 242 - 1 ) {
                        nextY = -512;
                }

                prevX = 1;
                nextX = 1;

                for ( j = 0; j < 320; j++, rgb += 3 ) {
                        const int x = ( j * 512 ) / 320;
                        const u8 * const src = &data[x];

                        if ( x == 512 - 1 ) {
                                nextX = -1;
                        }

                        Cr = ( src[prevX] - src[0] ) +
                                ( src[nextX] - src[0] );
                        Cr /= 2;

                        Cb = ( src[prevY] - src[prevX + prevY] ) +
                                ( src[prevY] - src[nextX + prevY] ) +
                                ( src[nextY] - src[prevX + nextY] ) +
                                ( src[nextY] - src[nextX + nextY] );
                        Cb /= 4;

                        Y = 1160 * ( src[0] + ( Cr / 2 ) - 16 );

                        if ( i & 1 ) {
                                int Ct = Cr;
                                Cr = Cb;
                                Cb = Ct;
                        }

                        if ( ( x ^ i ) & 1 ) {
                                Cr = -Cr;
                                Cb = -Cb;
                        }

                        rgb[0] = clamp( ( ( Y + ( 2017 * Cb ) ) +
                                        500 ) / 900, 0, 255 );
                        rgb[1] = clamp( ( ( Y - ( 392 * Cb ) -
                                          ( 813 * Cr ) ) +
                                          500 ) / 1000, 0, 255 );
                        rgb[2] = clamp( ( ( Y + ( 1594 * Cr ) ) +
                                        500 ) / 1300, 0, 255 );

                        prevX = -1;
                }

                prevY = -512;
        }
}

static void
read_frame(struct vicam_camera *cam, int framenum)
{
        unsigned char *request = cam->cntrlbuf;
        int realShutter;
        int n;
        int actual_length;

        if (cam->needsDummyRead) {
                cam->needsDummyRead = 0;
                read_frame(cam, framenum);
        }

        memset(request, 0, 16);
        request[0] = cam->gain; // 0 = 0% gain, FF = 100% gain

        request[1] = 0; // 512x242 capture

        request[2] = 0x90;      // the function of these two bytes
        request[3] = 0x07;      // is not yet understood

        if (cam->shutter_speed > 60) {
                // Short exposure
                realShutter =
                    ((-15631900 / cam->shutter_speed) + 260533) / 1000;
                request[4] = realShutter & 0xFF;
                request[5] = (realShutter >> 8) & 0xFF;
                request[6] = 0x03;
                request[7] = 0x01;
        } else {
                // Long exposure
                realShutter = 15600 / cam->shutter_speed - 1;
                request[4] = 0;
                request[5] = 0;
                request[6] = realShutter & 0xFF;
                request[7] = realShutter >> 8;
        }

        // Per John Markus Bjørndalen, byte at index 8 causes problems if it isn't 0
        request[8] = 0;
        // bytes 9-15 do not seem to affect exposure or image quality

        mutex_lock(&cam->cam_lock);

        if (!cam->udev) {
                goto done;
        }

        n = __send_control_msg(cam, 0x51, 0x80, 0, request, 16);

        if (n < 0) {
                printk(KERN_ERR
                       " Problem sending frame capture control message");
                goto done;
        }

        n = usb_bulk_msg(cam->udev,
                         usb_rcvbulkpipe(cam->udev, cam->bulkEndpoint),
                         cam->raw_image,
                         512 * 242 + 128, &actual_length, 10000);

        if (n < 0) {
                printk(KERN_ERR "Problem during bulk read of frame data: %d\n",
                       n);
        }

 done:
        mutex_unlock(&cam->cam_lock);
}

static ssize_t
vicam_read( struct file *file, char __user *buf, size_t count, loff_t *ppos )
{
        struct vicam_camera *cam = file->private_data;

        DBG("read %d bytes.\n", (int) count);

        if (*ppos >= VICAM_MAX_FRAME_SIZE) {
                *ppos = 0;
                return 0;
        }

        if (*ppos == 0) {
                read_frame(cam, 0);
                vicam_decode_color(cam->raw_image,
                                   cam->framebuf +
                                   0 * VICAM_MAX_FRAME_SIZE);
        }

        count = min_t(size_t, count, VICAM_MAX_FRAME_SIZE - *ppos);

        if (copy_to_user(buf, &cam->framebuf[*ppos], count)) {
                count = -EFAULT;
        } else {
                *ppos += count;
        }

        if (count == VICAM_MAX_FRAME_SIZE) {
                *ppos = 0;
        }

        return count;
}


static int
vicam_mmap(struct file *file, struct vm_area_struct *vma)
{
        // TODO: allocate the raw frame buffer if necessary
        unsigned long page, pos;
        unsigned long start = vma->vm_start;
        unsigned long size  = vma->vm_end-vma->vm_start;
        struct vicam_camera *cam = file->private_data;

        if (!cam)
                return -ENODEV;

        DBG("vicam_mmap: %ld\n", size);

        /* We let mmap allocate as much as it wants because Linux was adding 2048 bytes
         * to the size the application requested for mmap and it was screwing apps up.
         if (size > VICAM_FRAMES*VICAM_MAX_FRAME_SIZE)
         return -EINVAL;
         */

        pos = (unsigned long)cam->framebuf;
        while (size > 0) {
                page = vmalloc_to_pfn((void *)pos);
                if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
                        return -EAGAIN;

                start += PAGE_SIZE;
                pos += PAGE_SIZE;
                if (size > PAGE_SIZE)
                        size -= PAGE_SIZE;
                else
                        size = 0;
        }

        return 0;
}

static const struct v4l2_file_operations vicam_fops = {
        .owner          = THIS_MODULE,
        .open           = vicam_open,
        .release        = vicam_close,
        .read           = vicam_read,
        .mmap           = vicam_mmap,
        .ioctl          = vicam_ioctl,
};

static struct video_device vicam_template = {
        .name           = "ViCam-based USB Camera",
        .fops           = &vicam_fops,
        .minor          = -1,
        .release        = video_device_release_empty,
};

/* table of devices that work with this driver */
static struct usb_device_id vicam_table[] = {
        {USB_DEVICE(USB_VICAM_VENDOR_ID, USB_VICAM_PRODUCT_ID)},
        {USB_DEVICE(USB_COMPRO_VENDOR_ID, USB_COMPRO_PRODUCT_ID)},
        {}                      /* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, vicam_table);

static struct usb_driver vicam_driver = {
        .name           = "vicam",
        .probe          = vicam_probe,
        .disconnect     = vicam_disconnect,
        .id_table       = vicam_table
};

/**
 *      vicam_probe
 *      @intf: the interface
 *      @id: the device id
 *
 *      Called by the usb core when a new device is connected that it thinks
 *      this driver might be interested in.
 */
static int
vicam_probe( struct usb_interface *intf, const struct usb_device_id *id)
{
        struct usb_device *dev = interface_to_usbdev(intf);
        int bulkEndpoint = 0;
        const struct usb_host_interface *interface;
        const struct usb_endpoint_descriptor *endpoint;
        struct vicam_camera *cam;

        printk(KERN_INFO "ViCam based webcam connected\n");

        interface = intf->cur_altsetting;

        DBG(KERN_DEBUG "Interface %d. has %u. endpoints!\n",
               interface->desc.bInterfaceNumber, (unsigned) (interface->desc.bNumEndpoints));
        endpoint = &interface->endpoint[0].desc;

        if (usb_endpoint_is_bulk_in(endpoint)) {
                /* we found a bulk in endpoint */
                bulkEndpoint = endpoint->bEndpointAddress;
        } else {
                printk(KERN_ERR
                       "No bulk in endpoint was found ?! (this is bad)\n");
        }

        if ((cam =
             kzalloc(sizeof (struct vicam_camera), GFP_KERNEL)) == NULL) {
                printk(KERN_WARNING
                       "could not allocate kernel memory for vicam_camera struct\n");
                return -ENOMEM;
        }


        cam->shutter_speed = 15;

        mutex_init(&cam->cam_lock);

        memcpy(&cam->vdev, &vicam_template, sizeof(vicam_template));
        video_set_drvdata(&cam->vdev, cam);

        cam->udev = dev;
        cam->bulkEndpoint = bulkEndpoint;

        if (video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1) < 0) {
                kfree(cam);
                printk(KERN_WARNING "video_register_device failed\n");
                return -EIO;
        }

        printk(KERN_INFO "ViCam webcam driver now controlling video device %d\n",
                        cam->vdev.num);

        usb_set_intfdata (intf, cam);

        return 0;
}

static void
vicam_disconnect(struct usb_interface *intf)
{
        int open_count;
        struct vicam_camera *cam = usb_get_intfdata (intf);
        usb_set_intfdata (intf, NULL);

        /* we must unregister the device before taking its
         * cam_lock. This is because the video open call
         * holds the same lock as video unregister. if we
         * unregister inside of the cam_lock and open also
         * uses the cam_lock, we get deadlock.
         */

        video_unregister_device(&cam->vdev);

        /* stop the camera from being used */

        mutex_lock(&cam->cam_lock);

        /* mark the camera as gone */

        cam->udev = NULL;

        /* the only thing left to do is synchronize with
         * our close/release function on who should release
         * the camera memory. if there are any users using the
         * camera, it's their job. if there are no users,
         * it's ours.
         */

        open_count = cam->open_count;

        mutex_unlock(&cam->cam_lock);

        if (!open_count) {
                kfree(cam);
        }

        printk(KERN_DEBUG "ViCam-based WebCam disconnected\n");
}

/*
 */
static int __init
usb_vicam_init(void)
{
        int retval;
        DBG(KERN_INFO "ViCam-based WebCam driver startup\n");
        retval = usb_register(&vicam_driver);
        if (retval)
                printk(KERN_WARNING "usb_register failed!\n");
        return retval;
}

static void __exit
usb_vicam_exit(void)
{
        DBG(KERN_INFO
               "ViCam-based WebCam driver shutdown\n");

        usb_deregister(&vicam_driver);
}

module_init(usb_vicam_init);
module_exit(usb_vicam_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_FIRMWARE("vicam/firmware.fw");