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sn9c102_core.c

/***************************************************************************
 * V4L2 driver for SN9C1xx PC Camera Controllers                           *
 *                                                                         *
 * Copyright (C) 2004-2007 by Luca Risolia <luca.risolia@studio.unibo.it>  *
 *                                                                         *
 * 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.               *
 ***************************************************************************/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/compiler.h>
#include <linux/ioctl.h>
#include <linux/poll.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/page-flags.h>
#include <linux/byteorder/generic.h>
#include <asm/page.h>
#include <asm/uaccess.h>

#include "sn9c102.h"

/*****************************************************************************/

#define SN9C102_MODULE_NAME     "V4L2 driver for SN9C1xx PC Camera Controllers"
#define SN9C102_MODULE_ALIAS    "sn9c1xx"
#define SN9C102_MODULE_AUTHOR   "(C) 2004-2007 Luca Risolia"
#define SN9C102_AUTHOR_EMAIL    "<luca.risolia@studio.unibo.it>"
#define SN9C102_MODULE_LICENSE  "GPL"
#define SN9C102_MODULE_VERSION  "1:1.47"
#define SN9C102_MODULE_VERSION_CODE  KERNEL_VERSION(1, 1, 47)

/*****************************************************************************/

MODULE_DEVICE_TABLE(usb, sn9c102_id_table);

MODULE_AUTHOR(SN9C102_MODULE_AUTHOR " " SN9C102_AUTHOR_EMAIL);
MODULE_DESCRIPTION(SN9C102_MODULE_NAME);
MODULE_ALIAS(SN9C102_MODULE_ALIAS);
MODULE_VERSION(SN9C102_MODULE_VERSION);
MODULE_LICENSE(SN9C102_MODULE_LICENSE);

static short video_nr[] = {[0 ... SN9C102_MAX_DEVICES-1] = -1};
module_param_array(video_nr, short, NULL, 0444);
MODULE_PARM_DESC(video_nr,
             " <-1|n[,...]>"
             "\nSpecify V4L2 minor mode number."
             "\n-1 = use next available (default)"
             "\n n = use minor number n (integer >= 0)"
             "\nYou can specify up to "__MODULE_STRING(SN9C102_MAX_DEVICES)
             " cameras this way."
             "\nFor example:"
             "\nvideo_nr=-1,2,-1 would assign minor number 2 to"
             "\nthe second camera and use auto for the first"
             "\none and for every other camera."
             "\n");

static short force_munmap[] = {[0 ... SN9C102_MAX_DEVICES-1] =
                         SN9C102_FORCE_MUNMAP};
module_param_array(force_munmap, bool, NULL, 0444);
MODULE_PARM_DESC(force_munmap,
             " <0|1[,...]>"
             "\nForce the application to unmap previously"
             "\nmapped buffer memory before calling any VIDIOC_S_CROP or"
             "\nVIDIOC_S_FMT ioctl's. Not all the applications support"
             "\nthis feature. This parameter is specific for each"
             "\ndetected camera."
             "\n0 = do not force memory unmapping"
             "\n1 = force memory unmapping (save memory)"
             "\nDefault value is "__MODULE_STRING(SN9C102_FORCE_MUNMAP)"."
             "\n");

static unsigned int frame_timeout[] = {[0 ... SN9C102_MAX_DEVICES-1] =
                               SN9C102_FRAME_TIMEOUT};
module_param_array(frame_timeout, uint, NULL, 0644);
MODULE_PARM_DESC(frame_timeout,
             " <0|n[,...]>"
             "\nTimeout for a video frame in seconds before"
             "\nreturning an I/O error; 0 for infinity."
             "\nThis parameter is specific for each detected camera."
             "\nDefault value is "__MODULE_STRING(SN9C102_FRAME_TIMEOUT)"."
             "\n");

#ifdef SN9C102_DEBUG
static unsigned short debug = SN9C102_DEBUG_LEVEL;
module_param(debug, ushort, 0644);
MODULE_PARM_DESC(debug,
             " <n>"
             "\nDebugging information level, from 0 to 3:"
             "\n0 = none (use carefully)"
             "\n1 = critical errors"
             "\n2 = significant informations"
             "\n3 = more verbose messages"
             "\nLevel 3 is useful for testing only."
             "\nDefault value is "__MODULE_STRING(SN9C102_DEBUG_LEVEL)"."
             "\n");
#endif

/*****************************************************************************/

static u32
sn9c102_request_buffers(struct sn9c102_device* cam, u32 count,
                  enum sn9c102_io_method io)
{
      struct v4l2_pix_format* p = &(cam->sensor.pix_format);
      struct v4l2_rect* r = &(cam->sensor.cropcap.bounds);
      size_t imagesize = cam->module_param.force_munmap || io == IO_READ ?
                     (p->width * p->height * p->priv) / 8 :
                     (r->width * r->height * p->priv) / 8;
      void* buff = NULL;
      u32 i;

      if (count > SN9C102_MAX_FRAMES)
            count = SN9C102_MAX_FRAMES;

      if (cam->bridge == BRIDGE_SN9C105 || cam->bridge == BRIDGE_SN9C120)
            imagesize += 589 + 2; /* length of JPEG header + EOI marker */

      cam->nbuffers = count;
      while (cam->nbuffers > 0) {
            if ((buff = vmalloc_32_user(cam->nbuffers *
                                  PAGE_ALIGN(imagesize))))
                  break;
            cam->nbuffers--;
      }

      for (i = 0; i < cam->nbuffers; i++) {
            cam->frame[i].bufmem = buff + i*PAGE_ALIGN(imagesize);
            cam->frame[i].buf.index = i;
            cam->frame[i].buf.m.offset = i*PAGE_ALIGN(imagesize);
            cam->frame[i].buf.length = imagesize;
            cam->frame[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
            cam->frame[i].buf.sequence = 0;
            cam->frame[i].buf.field = V4L2_FIELD_NONE;
            cam->frame[i].buf.memory = V4L2_MEMORY_MMAP;
            cam->frame[i].buf.flags = 0;
      }

      return cam->nbuffers;
}


static void sn9c102_release_buffers(struct sn9c102_device* cam)
{
      if (cam->nbuffers) {
            vfree(cam->frame[0].bufmem);
            cam->nbuffers = 0;
      }
      cam->frame_current = NULL;
}


static void sn9c102_empty_framequeues(struct sn9c102_device* cam)
{
      u32 i;

      INIT_LIST_HEAD(&cam->inqueue);
      INIT_LIST_HEAD(&cam->outqueue);

      for (i = 0; i < SN9C102_MAX_FRAMES; i++) {
            cam->frame[i].state = F_UNUSED;
            cam->frame[i].buf.bytesused = 0;
      }
}


static void sn9c102_requeue_outqueue(struct sn9c102_device* cam)
{
      struct sn9c102_frame_t *i;

      list_for_each_entry(i, &cam->outqueue, frame) {
            i->state = F_QUEUED;
            list_add(&i->frame, &cam->inqueue);
      }

      INIT_LIST_HEAD(&cam->outqueue);
}


static void sn9c102_queue_unusedframes(struct sn9c102_device* cam)
{
      unsigned long lock_flags;
      u32 i;

      for (i = 0; i < cam->nbuffers; i++)
            if (cam->frame[i].state == F_UNUSED) {
                  cam->frame[i].state = F_QUEUED;
                  spin_lock_irqsave(&cam->queue_lock, lock_flags);
                  list_add_tail(&cam->frame[i].frame, &cam->inqueue);
                  spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
            }
}

/*****************************************************************************/

/*
   Write a sequence of count value/register pairs. Returns -1 after the first
   failed write, or 0 for no errors.
*/
int sn9c102_write_regs(struct sn9c102_device* cam, const u8 valreg[][2],
                   int count)
{
      struct usb_device* udev = cam->usbdev;
      u8* buff = cam->control_buffer;
      int i, res;

      for (i = 0; i < count; i++) {
            u8 index = valreg[i][1];

            /*
               index is a u8, so it must be <256 and can't be out of range.
               If we put in a check anyway, gcc annoys us with a warning
               hat our check is useless. People get all uppity when they
               see warnings in the kernel compile.
            */

            *buff = valreg[i][0];

            res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x08,
                              0x41, index, 0, buff, 1,
                              SN9C102_CTRL_TIMEOUT);

            if (res < 0) {
                  DBG(3, "Failed to write a register (value 0x%02X, "
                         "index 0x%02X, error %d)", *buff, index, res);
                  return -1;
            }

            cam->reg[index] = *buff;
      }

      return 0;
}


int sn9c102_write_reg(struct sn9c102_device* cam, u8 value, u16 index)
{
      struct usb_device* udev = cam->usbdev;
      u8* buff = cam->control_buffer;
      int res;

      if (index >= ARRAY_SIZE(cam->reg))
            return -1;

      *buff = value;

      res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x08, 0x41,
                        index, 0, buff, 1, SN9C102_CTRL_TIMEOUT);
      if (res < 0) {
            DBG(3, "Failed to write a register (value 0x%02X, index "
                   "0x%02X, error %d)", value, index, res);
            return -1;
      }

      cam->reg[index] = value;

      return 0;
}


/* NOTE: with the SN9C10[123] reading some registers always returns 0 */
int sn9c102_read_reg(struct sn9c102_device* cam, u16 index)
{
      struct usb_device* udev = cam->usbdev;
      u8* buff = cam->control_buffer;
      int res;

      res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0x00, 0xc1,
                        index, 0, buff, 1, SN9C102_CTRL_TIMEOUT);
      if (res < 0)
            DBG(3, "Failed to read a register (index 0x%02X, error %d)",
                index, res);

      return (res >= 0) ? (int)(*buff) : -1;
}


int sn9c102_pread_reg(struct sn9c102_device* cam, u16 index)
{
      if (index >= ARRAY_SIZE(cam->reg))
            return -1;

      return cam->reg[index];
}


static int
sn9c102_i2c_wait(struct sn9c102_device* cam,
             const struct sn9c102_sensor* sensor)
{
      int i, r;

      for (i = 1; i <= 5; i++) {
            r = sn9c102_read_reg(cam, 0x08);
            if (r < 0)
                  return -EIO;
            if (r & 0x04)
                  return 0;
            if (sensor->frequency & SN9C102_I2C_400KHZ)
                  udelay(5*16);
            else
                  udelay(16*16);
      }
      return -EBUSY;
}


static int
sn9c102_i2c_detect_read_error(struct sn9c102_device* cam,
                        const struct sn9c102_sensor* sensor)
{
      int r , err = 0;

      r = sn9c102_read_reg(cam, 0x08);
      if (r < 0)
            err += r;

      if (cam->bridge == BRIDGE_SN9C101 || cam->bridge == BRIDGE_SN9C102) {
            if (!(r & 0x08))
                  err += -1;
      } else {
            if (r & 0x08)
                  err += -1;
      }

      return err ? -EIO : 0;
}


static int
sn9c102_i2c_detect_write_error(struct sn9c102_device* cam,
                         const struct sn9c102_sensor* sensor)
{
      int r;
      r = sn9c102_read_reg(cam, 0x08);
      return (r < 0 || (r >= 0 && (r & 0x08))) ? -EIO : 0;
}


int
sn9c102_i2c_try_raw_read(struct sn9c102_device* cam,
                   const struct sn9c102_sensor* sensor, u8 data0,
                   u8 data1, u8 n, u8 buffer[])
{
      struct usb_device* udev = cam->usbdev;
      u8* data = cam->control_buffer;
      int i = 0, err = 0, res;

      /* Write cycle */
      data[0] = ((sensor->interface == SN9C102_I2C_2WIRES) ? 0x80 : 0) |
              ((sensor->frequency & SN9C102_I2C_400KHZ) ? 0x01 : 0) | 0x10;
      data[1] = data0; /* I2C slave id */
      data[2] = data1; /* address */
      data[7] = 0x10;
      res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x08, 0x41,
                        0x08, 0, data, 8, SN9C102_CTRL_TIMEOUT);
      if (res < 0)
            err += res;

      err += sn9c102_i2c_wait(cam, sensor);

      /* Read cycle - n bytes */
      data[0] = ((sensor->interface == SN9C102_I2C_2WIRES) ? 0x80 : 0) |
              ((sensor->frequency & SN9C102_I2C_400KHZ) ? 0x01 : 0) |
              (n << 4) | 0x02;
      data[1] = data0;
      data[7] = 0x10;
      res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x08, 0x41,
                        0x08, 0, data, 8, SN9C102_CTRL_TIMEOUT);
      if (res < 0)
            err += res;

      err += sn9c102_i2c_wait(cam, sensor);

      /* The first read byte will be placed in data[4] */
      res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0x00, 0xc1,
                        0x0a, 0, data, 5, SN9C102_CTRL_TIMEOUT);
      if (res < 0)
            err += res;

      err += sn9c102_i2c_detect_read_error(cam, sensor);

      PDBGG("I2C read: address 0x%02X, first read byte: 0x%02X", data1,
            data[4]);

      if (err) {
            DBG(3, "I2C read failed for %s image sensor", sensor->name);
            return -1;
      }

      if (buffer)
            for (i = 0; i < n && i < 5; i++)
                  buffer[n-i-1] = data[4-i];

      return (int)data[4];
}


int
sn9c102_i2c_try_raw_write(struct sn9c102_device* cam,
                    const struct sn9c102_sensor* sensor, u8 n, u8 data0,
                    u8 data1, u8 data2, u8 data3, u8 data4, u8 data5)
{
      struct usb_device* udev = cam->usbdev;
      u8* data = cam->control_buffer;
      int err = 0, res;

      /* Write cycle. It usually is address + value */
      data[0] = ((sensor->interface == SN9C102_I2C_2WIRES) ? 0x80 : 0) |
              ((sensor->frequency & SN9C102_I2C_400KHZ) ? 0x01 : 0)
              | ((n - 1) << 4);
      data[1] = data0;
      data[2] = data1;
      data[3] = data2;
      data[4] = data3;
      data[5] = data4;
      data[6] = data5;
      data[7] = 0x17;
      res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x08, 0x41,
                        0x08, 0, data, 8, SN9C102_CTRL_TIMEOUT);
      if (res < 0)
            err += res;

      err += sn9c102_i2c_wait(cam, sensor);
      err += sn9c102_i2c_detect_write_error(cam, sensor);

      if (err)
            DBG(3, "I2C write failed for %s image sensor", sensor->name);

      PDBGG("I2C raw write: %u bytes, data0 = 0x%02X, data1 = 0x%02X, "
            "data2 = 0x%02X, data3 = 0x%02X, data4 = 0x%02X, data5 = 0x%02X",
            n, data0, data1, data2, data3, data4, data5);

      return err ? -1 : 0;
}


int
sn9c102_i2c_try_read(struct sn9c102_device* cam,
                 const struct sn9c102_sensor* sensor, u8 address)
{
      return sn9c102_i2c_try_raw_read(cam, sensor, sensor->i2c_slave_id,
                              address, 1, NULL);
}


int
sn9c102_i2c_try_write(struct sn9c102_device* cam,
                  const struct sn9c102_sensor* sensor, u8 address, u8 value)
{
      return sn9c102_i2c_try_raw_write(cam, sensor, 3,
                               sensor->i2c_slave_id, address,
                               value, 0, 0, 0);
}


int sn9c102_i2c_read(struct sn9c102_device* cam, u8 address)
{
      return sn9c102_i2c_try_read(cam, &cam->sensor, address);
}


int sn9c102_i2c_write(struct sn9c102_device* cam, u8 address, u8 value)
{
      return sn9c102_i2c_try_write(cam, &cam->sensor, address, value);
}

/*****************************************************************************/

static size_t sn9c102_sof_length(struct sn9c102_device* cam)
{
      switch (cam->bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
            return 12;
      case BRIDGE_SN9C103:
            return 18;
      case BRIDGE_SN9C105:
      case BRIDGE_SN9C120:
            return 62;
      }

      return 0;
}


static void*
sn9c102_find_sof_header(struct sn9c102_device* cam, void* mem, size_t len)
{
      static const char marker[6] = {0xff, 0xff, 0x00, 0xc4, 0xc4, 0x96};
      const char *m = mem;
      size_t soflen = 0, i, j;

      soflen = sn9c102_sof_length(cam);

      for (i = 0; i < len; i++) {
            size_t b;

            /* Read the variable part of the header */
            if (unlikely(cam->sof.bytesread >= sizeof(marker))) {
                  cam->sof.header[cam->sof.bytesread] = *(m+i);
                  if (++cam->sof.bytesread == soflen) {
                        cam->sof.bytesread = 0;
                        return mem + i;
                  }
                  continue;
            }

            /* Search for the SOF marker (fixed part) in the header */
            for (j = 0, b=cam->sof.bytesread; j+b < sizeof(marker); j++) {
                  if (unlikely(i+j) == len)
                        return NULL;
                  if (*(m+i+j) == marker[cam->sof.bytesread]) {
                        cam->sof.header[cam->sof.bytesread] = *(m+i+j);
                        if (++cam->sof.bytesread == sizeof(marker)) {
                              PDBGG("Bytes to analyze: %zd. SOF "
                                    "starts at byte #%zd", len, i);
                              i += j+1;
                              break;
                        }
                  } else {
                        cam->sof.bytesread = 0;
                        break;
                  }
            }
      }

      return NULL;
}


static void*
sn9c102_find_eof_header(struct sn9c102_device* cam, void* mem, size_t len)
{
      static const u8 eof_header[4][4] = {
            {0x00, 0x00, 0x00, 0x00},
            {0x40, 0x00, 0x00, 0x00},
            {0x80, 0x00, 0x00, 0x00},
            {0xc0, 0x00, 0x00, 0x00},
      };
      size_t i, j;

      /* The EOF header does not exist in compressed data */
      if (cam->sensor.pix_format.pixelformat == V4L2_PIX_FMT_SN9C10X ||
          cam->sensor.pix_format.pixelformat == V4L2_PIX_FMT_JPEG)
            return NULL;

      /*
         The EOF header might cross the packet boundary, but this is not a
         problem, since the end of a frame is determined by checking its size
         in the first place.
      */
      for (i = 0; (len >= 4) && (i <= len - 4); i++)
            for (j = 0; j < ARRAY_SIZE(eof_header); j++)
                  if (!memcmp(mem + i, eof_header[j], 4))
                        return mem + i;

      return NULL;
}


static void
sn9c102_write_jpegheader(struct sn9c102_device* cam, struct sn9c102_frame_t* f)
{
      static const u8 jpeg_header[589] = {
            0xff, 0xd8, 0xff, 0xdb, 0x00, 0x84, 0x00, 0x06, 0x04, 0x05,
            0x06, 0x05, 0x04, 0x06, 0x06, 0x05, 0x06, 0x07, 0x07, 0x06,
            0x08, 0x0a, 0x10, 0x0a, 0x0a, 0x09, 0x09, 0x0a, 0x14, 0x0e,
            0x0f, 0x0c, 0x10, 0x17, 0x14, 0x18, 0x18, 0x17, 0x14, 0x16,
            0x16, 0x1a, 0x1d, 0x25, 0x1f, 0x1a, 0x1b, 0x23, 0x1c, 0x16,
            0x16, 0x20, 0x2c, 0x20, 0x23, 0x26, 0x27, 0x29, 0x2a, 0x29,
            0x19, 0x1f, 0x2d, 0x30, 0x2d, 0x28, 0x30, 0x25, 0x28, 0x29,
            0x28, 0x01, 0x07, 0x07, 0x07, 0x0a, 0x08, 0x0a, 0x13, 0x0a,
            0x0a, 0x13, 0x28, 0x1a, 0x16, 0x1a, 0x28, 0x28, 0x28, 0x28,
            0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28,
            0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28,
            0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28,
            0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28,
            0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0xff, 0xc4, 0x01, 0xa2,
            0x00, 0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02,
            0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x01,
            0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
            0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
            0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x10, 0x00,
            0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05, 0x05, 0x04,
            0x04, 0x00, 0x00, 0x01, 0x7d, 0x01, 0x02, 0x03, 0x00, 0x04,
            0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61,
            0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23,
            0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62,
            0x72, 0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25,
            0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38,
            0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
            0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64,
            0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76,
            0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88,
            0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
            0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa,
            0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2,
            0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3,
            0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3,
            0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3,
            0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0x11, 0x00, 0x02,
            0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05, 0x04, 0x04,
            0x00, 0x01, 0x02, 0x77, 0x00, 0x01, 0x02, 0x03, 0x11, 0x04,
            0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
            0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1,
            0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1,
            0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19,
            0x1a, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
            0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
            0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64,
            0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76,
            0x77, 0x78, 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
            0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
            0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9,
            0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
            0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
            0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3,
            0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4,
            0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xff, 0xc0, 0x00, 0x11,
            0x08, 0x01, 0xe0, 0x02, 0x80, 0x03, 0x01, 0x21, 0x00, 0x02,
            0x11, 0x01, 0x03, 0x11, 0x01, 0xff, 0xda, 0x00, 0x0c, 0x03,
            0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00
      };
      u8 *pos = f->bufmem;

      memcpy(pos, jpeg_header, sizeof(jpeg_header));
      *(pos + 6) = 0x00;
      *(pos + 7 + 64) = 0x01;
      if (cam->compression.quality == 0) {
            memcpy(pos + 7, SN9C102_Y_QTABLE0, 64);
            memcpy(pos + 8 + 64, SN9C102_UV_QTABLE0, 64);
      } else if (cam->compression.quality == 1) {
            memcpy(pos + 7, SN9C102_Y_QTABLE1, 64);
            memcpy(pos + 8 + 64, SN9C102_UV_QTABLE1, 64);
      }
      *(pos + 564) = cam->sensor.pix_format.width & 0xFF;
      *(pos + 563) = (cam->sensor.pix_format.width >> 8) & 0xFF;
      *(pos + 562) = cam->sensor.pix_format.height & 0xFF;
      *(pos + 561) = (cam->sensor.pix_format.height >> 8) & 0xFF;
      *(pos + 567) = 0x21;

      f->buf.bytesused += sizeof(jpeg_header);
}


static void sn9c102_urb_complete(struct urb *urb)
{
      struct sn9c102_device* cam = urb->context;
      struct sn9c102_frame_t** f;
      size_t imagesize, soflen;
      u8 i;
      int err = 0;

      if (urb->status == -ENOENT)
            return;

      f = &cam->frame_current;

      if (cam->stream == STREAM_INTERRUPT) {
            cam->stream = STREAM_OFF;
            if ((*f))
                  (*f)->state = F_QUEUED;
            cam->sof.bytesread = 0;
            DBG(3, "Stream interrupted by application");
            wake_up(&cam->wait_stream);
      }

      if (cam->state & DEV_DISCONNECTED)
            return;

      if (cam->state & DEV_MISCONFIGURED) {
            wake_up_interruptible(&cam->wait_frame);
            return;
      }

      if (cam->stream == STREAM_OFF || list_empty(&cam->inqueue))
            goto resubmit_urb;

      if (!(*f))
            (*f) = list_entry(cam->inqueue.next, struct sn9c102_frame_t,
                          frame);

      imagesize = (cam->sensor.pix_format.width *
                 cam->sensor.pix_format.height *
                 cam->sensor.pix_format.priv) / 8;
      if (cam->sensor.pix_format.pixelformat == V4L2_PIX_FMT_JPEG)
            imagesize += 589; /* length of jpeg header */
      soflen = sn9c102_sof_length(cam);

      for (i = 0; i < urb->number_of_packets; i++) {
            unsigned int img, len, status;
            void *pos, *sof, *eof;

            len = urb->iso_frame_desc[i].actual_length;
            status = urb->iso_frame_desc[i].status;
            pos = urb->iso_frame_desc[i].offset + urb->transfer_buffer;

            if (status) {
                  DBG(3, "Error in isochronous frame");
                  (*f)->state = F_ERROR;
                  cam->sof.bytesread = 0;
                  continue;
            }

            PDBGG("Isochrnous frame: length %u, #%u i", len, i);

redo:
            sof = sn9c102_find_sof_header(cam, pos, len);
            if (likely(!sof)) {
                  eof = sn9c102_find_eof_header(cam, pos, len);
                  if ((*f)->state == F_GRABBING) {
end_of_frame:
                        img = len;

                        if (eof)
                              img = (eof > pos) ? eof - pos - 1 : 0;

                        if ((*f)->buf.bytesused + img > imagesize) {
                              u32 b;
                              b = (*f)->buf.bytesused + img -
                                  imagesize;
                              img = imagesize - (*f)->buf.bytesused;
                              PDBGG("Expected EOF not found: video "
                                    "frame cut");
                              if (eof)
                                    DBG(3, "Exceeded limit: +%u "
                                           "bytes", (unsigned)(b));
                        }

                        memcpy((*f)->bufmem + (*f)->buf.bytesused, pos,
                               img);

                        if ((*f)->buf.bytesused == 0)
                              do_gettimeofday(&(*f)->buf.timestamp);

                        (*f)->buf.bytesused += img;

                        if ((*f)->buf.bytesused == imagesize ||
                            ((cam->sensor.pix_format.pixelformat ==
                              V4L2_PIX_FMT_SN9C10X ||
                              cam->sensor.pix_format.pixelformat ==
                              V4L2_PIX_FMT_JPEG) && eof)) {
                              u32 b;

                              b = (*f)->buf.bytesused;
                              (*f)->state = F_DONE;
                              (*f)->buf.sequence= ++cam->frame_count;

                              spin_lock(&cam->queue_lock);
                              list_move_tail(&(*f)->frame,
                                           &cam->outqueue);
                              if (!list_empty(&cam->inqueue))
                                    (*f) = list_entry(
                                          cam->inqueue.next,
                                          struct sn9c102_frame_t,
                                          frame );
                              else
                                    (*f) = NULL;
                              spin_unlock(&cam->queue_lock);

                              memcpy(cam->sysfs.frame_header,
                                     cam->sof.header, soflen);

                              DBG(3, "Video frame captured: %lu "
                                     "bytes", (unsigned long)(b));

                              if (!(*f))
                                    goto resubmit_urb;

                        } else if (eof) {
                              (*f)->state = F_ERROR;
                              DBG(3, "Not expected EOF after %lu "
                                     "bytes of image data",
                                  (unsigned long)
                                  ((*f)->buf.bytesused));
                        }

                        if (sof) /* (1) */
                              goto start_of_frame;

                  } else if (eof) {
                        DBG(3, "EOF without SOF");
                        continue;

                  } else {
                        PDBGG("Ignoring pointless isochronous frame");
                        continue;
                  }

            } else if ((*f)->state == F_QUEUED || (*f)->state == F_ERROR) {
start_of_frame:
                  (*f)->state = F_GRABBING;
                  (*f)->buf.bytesused = 0;
                  len -= (sof - pos);
                  pos = sof;
                  if (cam->sensor.pix_format.pixelformat ==
                      V4L2_PIX_FMT_JPEG)
                        sn9c102_write_jpegheader(cam, (*f));
                  DBG(3, "SOF detected: new video frame");
                  if (len)
                        goto redo;

            } else if ((*f)->state == F_GRABBING) {
                  eof = sn9c102_find_eof_header(cam, pos, len);
                  if (eof && eof < sof)
                        goto end_of_frame; /* (1) */
                  else {
                        if (cam->sensor.pix_format.pixelformat ==
                            V4L2_PIX_FMT_SN9C10X ||
                            cam->sensor.pix_format.pixelformat ==
                            V4L2_PIX_FMT_JPEG) {
                              if (sof - pos >= soflen) {
                                    eof = sof - soflen;
                              } else { /* remove header */
                                    eof = pos;
                                    (*f)->buf.bytesused -=
                                          (soflen - (sof - pos));
                              }
                              goto end_of_frame;
                        } else {
                              DBG(3, "SOF before expected EOF after "
                                     "%lu bytes of image data",
                                  (unsigned long)
                                  ((*f)->buf.bytesused));
                              goto start_of_frame;
                        }
                  }
            }
      }

resubmit_urb:
      urb->dev = cam->usbdev;
      err = usb_submit_urb(urb, GFP_ATOMIC);
      if (err < 0 && err != -EPERM) {
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "usb_submit_urb() failed");
      }

      wake_up_interruptible(&cam->wait_frame);
}


static int sn9c102_start_transfer(struct sn9c102_device* cam)
{
      struct usb_device *udev = cam->usbdev;
      struct urb* urb;
      struct usb_host_interface* altsetting = usb_altnum_to_altsetting(
                                        usb_ifnum_to_if(udev, 0),
                                        SN9C102_ALTERNATE_SETTING);
      const unsigned int psz = le16_to_cpu(altsetting->
                                   endpoint[0].desc.wMaxPacketSize);
      s8 i, j;
      int err = 0;

      for (i = 0; i < SN9C102_URBS; i++) {
            cam->transfer_buffer[i] = kzalloc(SN9C102_ISO_PACKETS * psz,
                                      GFP_KERNEL);
            if (!cam->transfer_buffer[i]) {
                  err = -ENOMEM;
                  DBG(1, "Not enough memory");
                  goto free_buffers;
            }
      }

      for (i = 0; i < SN9C102_URBS; i++) {
            urb = usb_alloc_urb(SN9C102_ISO_PACKETS, GFP_KERNEL);
            cam->urb[i] = urb;
            if (!urb) {
                  err = -ENOMEM;
                  DBG(1, "usb_alloc_urb() failed");
                  goto free_urbs;
            }
            urb->dev = udev;
            urb->context = cam;
            urb->pipe = usb_rcvisocpipe(udev, 1);
            urb->transfer_flags = URB_ISO_ASAP;
            urb->number_of_packets = SN9C102_ISO_PACKETS;
            urb->complete = sn9c102_urb_complete;
            urb->transfer_buffer = cam->transfer_buffer[i];
            urb->transfer_buffer_length = psz * SN9C102_ISO_PACKETS;
            urb->interval = 1;
            for (j = 0; j < SN9C102_ISO_PACKETS; j++) {
                  urb->iso_frame_desc[j].offset = psz * j;
                  urb->iso_frame_desc[j].length = psz;
            }
      }

      /* Enable video */
      if (!(cam->reg[0x01] & 0x04)) {
            err = sn9c102_write_reg(cam, cam->reg[0x01] | 0x04, 0x01);
            if (err) {
                  err = -EIO;
                  DBG(1, "I/O hardware error");
                  goto free_urbs;
            }
      }

      err = usb_set_interface(udev, 0, SN9C102_ALTERNATE_SETTING);
      if (err) {
            DBG(1, "usb_set_interface() failed");
            goto free_urbs;
      }

      cam->frame_current = NULL;
      cam->sof.bytesread = 0;

      for (i = 0; i < SN9C102_URBS; i++) {
            err = usb_submit_urb(cam->urb[i], GFP_KERNEL);
            if (err) {
                  for (j = i-1; j >= 0; j--)
                        usb_kill_urb(cam->urb[j]);
                  DBG(1, "usb_submit_urb() failed, error %d", err);
                  goto free_urbs;
            }
      }

      return 0;

free_urbs:
      for (i = 0; (i < SN9C102_URBS) && cam->urb[i]; i++)
            usb_free_urb(cam->urb[i]);

free_buffers:
      for (i = 0; (i < SN9C102_URBS) && cam->transfer_buffer[i]; i++)
            kfree(cam->transfer_buffer[i]);

      return err;
}


static int sn9c102_stop_transfer(struct sn9c102_device* cam)
{
      struct usb_device *udev = cam->usbdev;
      s8 i;
      int err = 0;

      if (cam->state & DEV_DISCONNECTED)
            return 0;

      for (i = SN9C102_URBS-1; i >= 0; i--) {
            usb_kill_urb(cam->urb[i]);
            usb_free_urb(cam->urb[i]);
            kfree(cam->transfer_buffer[i]);
      }

      err = usb_set_interface(udev, 0, 0); /* 0 Mb/s */
      if (err)
            DBG(3, "usb_set_interface() failed");

      return err;
}


static int sn9c102_stream_interrupt(struct sn9c102_device* cam)
{
      long timeout;

      cam->stream = STREAM_INTERRUPT;
      timeout = wait_event_timeout(cam->wait_stream,
                             (cam->stream == STREAM_OFF) ||
                             (cam->state & DEV_DISCONNECTED),
                             SN9C102_URB_TIMEOUT);
      if (cam->state & DEV_DISCONNECTED)
            return -ENODEV;
      else if (cam->stream != STREAM_OFF) {
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "URB timeout reached. The camera is misconfigured. "
                   "To use it, close and open /dev/video%d again.",
                cam->v4ldev->minor);
            return -EIO;
      }

      return 0;
}

/*****************************************************************************/

#ifdef CONFIG_VIDEO_ADV_DEBUG
static u16 sn9c102_strtou16(const char* buff, size_t len, ssize_t* count)
{
      char str[7];
      char* endp;
      unsigned long val;

      if (len < 6) {
            strncpy(str, buff, len);
            str[len] = '\0';
      } else {
            strncpy(str, buff, 6);
            str[6] = '\0';
      }

      val = simple_strtoul(str, &endp, 0);

      *count = 0;
      if (val <= 0xffff)
            *count = (ssize_t)(endp - str);
      if ((*count) && (len == *count+1) && (buff[*count] == '\n'))
            *count += 1;

      return (u16)val;
}

/*
   NOTE 1: being inside one of the following methods implies that the v4l
         device exists for sure (see kobjects and reference counters)
   NOTE 2: buffers are PAGE_SIZE long
*/

static ssize_t sn9c102_show_reg(struct device* cd,
                        struct device_attribute *attr, char* buf)
{
      struct sn9c102_device* cam;
      ssize_t count;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      count = sprintf(buf, "%u\n", cam->sysfs.reg);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t
sn9c102_store_reg(struct device* cd, struct device_attribute *attr,
              const char* buf, size_t len)
{
      struct sn9c102_device* cam;
      u16 index;
      ssize_t count;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      index = sn9c102_strtou16(buf, len, &count);
      if (index >= ARRAY_SIZE(cam->reg) || !count) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EINVAL;
      }

      cam->sysfs.reg = index;

      DBG(2, "Moved SN9C1XX register index to 0x%02X", cam->sysfs.reg);
      DBG(3, "Written bytes: %zd", count);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t sn9c102_show_val(struct device* cd,
                        struct device_attribute *attr, char* buf)
{
      struct sn9c102_device* cam;
      ssize_t count;
      int val;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      if ((val = sn9c102_read_reg(cam, cam->sysfs.reg)) < 0) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EIO;
      }

      count = sprintf(buf, "%d\n", val);

      DBG(3, "Read bytes: %zd, value: %d", count, val);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t
sn9c102_store_val(struct device* cd, struct device_attribute *attr,
              const char* buf, size_t len)
{
      struct sn9c102_device* cam;
      u16 value;
      ssize_t count;
      int err;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      value = sn9c102_strtou16(buf, len, &count);
      if (!count) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EINVAL;
      }

      err = sn9c102_write_reg(cam, value, cam->sysfs.reg);
      if (err) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EIO;
      }

      DBG(2, "Written SN9C1XX reg. 0x%02X, val. 0x%02X",
          cam->sysfs.reg, value);
      DBG(3, "Written bytes: %zd", count);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t sn9c102_show_i2c_reg(struct device* cd,
                            struct device_attribute *attr, char* buf)
{
      struct sn9c102_device* cam;
      ssize_t count;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      count = sprintf(buf, "%u\n", cam->sysfs.i2c_reg);

      DBG(3, "Read bytes: %zd", count);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t
sn9c102_store_i2c_reg(struct device* cd, struct device_attribute *attr,
                  const char* buf, size_t len)
{
      struct sn9c102_device* cam;
      u16 index;
      ssize_t count;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      index = sn9c102_strtou16(buf, len, &count);
      if (!count) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EINVAL;
      }

      cam->sysfs.i2c_reg = index;

      DBG(2, "Moved sensor register index to 0x%02X", cam->sysfs.i2c_reg);
      DBG(3, "Written bytes: %zd", count);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t sn9c102_show_i2c_val(struct device* cd,
                            struct device_attribute *attr, char* buf)
{
      struct sn9c102_device* cam;
      ssize_t count;
      int val;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      if (!(cam->sensor.sysfs_ops & SN9C102_I2C_READ)) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENOSYS;
      }

      if ((val = sn9c102_i2c_read(cam, cam->sysfs.i2c_reg)) < 0) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EIO;
      }

      count = sprintf(buf, "%d\n", val);

      DBG(3, "Read bytes: %zd, value: %d", count, val);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t
sn9c102_store_i2c_val(struct device* cd, struct device_attribute *attr,
                  const char* buf, size_t len)
{
      struct sn9c102_device* cam;
      u16 value;
      ssize_t count;
      int err;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      if (!(cam->sensor.sysfs_ops & SN9C102_I2C_WRITE)) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENOSYS;
      }

      value = sn9c102_strtou16(buf, len, &count);
      if (!count) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EINVAL;
      }

      err = sn9c102_i2c_write(cam, cam->sysfs.i2c_reg, value);
      if (err) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -EIO;
      }

      DBG(2, "Written sensor reg. 0x%02X, val. 0x%02X",
          cam->sysfs.i2c_reg, value);
      DBG(3, "Written bytes: %zd", count);

      mutex_unlock(&sn9c102_sysfs_lock);

      return count;
}


static ssize_t
sn9c102_store_green(struct device* cd, struct device_attribute *attr,
                const char* buf, size_t len)
{
      struct sn9c102_device* cam;
      enum sn9c102_bridge bridge;
      ssize_t res = 0;
      u16 value;
      ssize_t count;

      if (mutex_lock_interruptible(&sn9c102_sysfs_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam) {
            mutex_unlock(&sn9c102_sysfs_lock);
            return -ENODEV;
      }

      bridge = cam->bridge;

      mutex_unlock(&sn9c102_sysfs_lock);

      value = sn9c102_strtou16(buf, len, &count);
      if (!count)
            return -EINVAL;

      switch (bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
            if (value > 0x0f)
                  return -EINVAL;
            if ((res = sn9c102_store_reg(cd, attr, "0x11", 4)) >= 0)
                  res = sn9c102_store_val(cd, attr, buf, len);
            break;
      case BRIDGE_SN9C103:
      case BRIDGE_SN9C105:
      case BRIDGE_SN9C120:
            if (value > 0x7f)
                  return -EINVAL;
            if ((res = sn9c102_store_reg(cd, attr, "0x07", 4)) >= 0)
                  res = sn9c102_store_val(cd, attr, buf, len);
            break;
      }

      return res;
}


static ssize_t
sn9c102_store_blue(struct device* cd, struct device_attribute *attr,
               const char* buf, size_t len)
{
      ssize_t res = 0;
      u16 value;
      ssize_t count;

      value = sn9c102_strtou16(buf, len, &count);
      if (!count || value > 0x7f)
            return -EINVAL;

      if ((res = sn9c102_store_reg(cd, attr, "0x06", 4)) >= 0)
            res = sn9c102_store_val(cd, attr, buf, len);

      return res;
}


static ssize_t
sn9c102_store_red(struct device* cd, struct device_attribute *attr,
              const char* buf, size_t len)
{
      ssize_t res = 0;
      u16 value;
      ssize_t count;

      value = sn9c102_strtou16(buf, len, &count);
      if (!count || value > 0x7f)
            return -EINVAL;

      if ((res = sn9c102_store_reg(cd, attr, "0x05", 4)) >= 0)
            res = sn9c102_store_val(cd, attr, buf, len);

      return res;
}


static ssize_t sn9c102_show_frame_header(struct device* cd,
                               struct device_attribute *attr,
                               char* buf)
{
      struct sn9c102_device* cam;
      ssize_t count;

      cam = video_get_drvdata(container_of(cd, struct video_device,
                                   class_dev));
      if (!cam)
            return -ENODEV;

      count = sizeof(cam->sysfs.frame_header);
      memcpy(buf, cam->sysfs.frame_header, count);

      DBG(3, "Frame header, read bytes: %zd", count);

      return count;
}


static DEVICE_ATTR(reg, S_IRUGO | S_IWUSR, sn9c102_show_reg, sn9c102_store_reg);
static DEVICE_ATTR(val, S_IRUGO | S_IWUSR, sn9c102_show_val, sn9c102_store_val);
static DEVICE_ATTR(i2c_reg, S_IRUGO | S_IWUSR,
               sn9c102_show_i2c_reg, sn9c102_store_i2c_reg);
static DEVICE_ATTR(i2c_val, S_IRUGO | S_IWUSR,
               sn9c102_show_i2c_val, sn9c102_store_i2c_val);
static DEVICE_ATTR(green, S_IWUGO, NULL, sn9c102_store_green);
static DEVICE_ATTR(blue, S_IWUGO, NULL, sn9c102_store_blue);
static DEVICE_ATTR(red, S_IWUGO, NULL, sn9c102_store_red);
static DEVICE_ATTR(frame_header, S_IRUGO, sn9c102_show_frame_header, NULL);


static int sn9c102_create_sysfs(struct sn9c102_device* cam)
{
      struct device *classdev = &(cam->v4ldev->class_dev);
      int err = 0;

      if ((err = device_create_file(classdev, &dev_attr_reg)))
            goto err_out;
      if ((err = device_create_file(classdev, &dev_attr_val)))
            goto err_reg;
      if ((err = device_create_file(classdev, &dev_attr_frame_header)))
            goto err_val;

      if (cam->sensor.sysfs_ops) {
            if ((err = device_create_file(classdev, &dev_attr_i2c_reg)))
                  goto err_frame_header;
            if ((err = device_create_file(classdev, &dev_attr_i2c_val)))
                  goto err_i2c_reg;
      }

      if (cam->bridge == BRIDGE_SN9C101 || cam->bridge == BRIDGE_SN9C102) {
            if ((err = device_create_file(classdev, &dev_attr_green)))
                  goto err_i2c_val;
      } else {
            if ((err = device_create_file(classdev, &dev_attr_blue)))
                  goto err_i2c_val;
            if ((err = device_create_file(classdev, &dev_attr_red)))
                  goto err_blue;
      }

      return 0;

err_blue:
      device_remove_file(classdev, &dev_attr_blue);
err_i2c_val:
      if (cam->sensor.sysfs_ops)
            device_remove_file(classdev, &dev_attr_i2c_val);
err_i2c_reg:
      if (cam->sensor.sysfs_ops)
            device_remove_file(classdev, &dev_attr_i2c_reg);
err_frame_header:
      device_remove_file(classdev, &dev_attr_frame_header);
err_val:
      device_remove_file(classdev, &dev_attr_val);
err_reg:
      device_remove_file(classdev, &dev_attr_reg);
err_out:
      return err;
}
#endif /* CONFIG_VIDEO_ADV_DEBUG */

/*****************************************************************************/

static int
sn9c102_set_pix_format(struct sn9c102_device* cam, struct v4l2_pix_format* pix)
{
      int err = 0;

      if (pix->pixelformat == V4L2_PIX_FMT_SN9C10X ||
          pix->pixelformat == V4L2_PIX_FMT_JPEG) {
            switch (cam->bridge) {
            case BRIDGE_SN9C101:
            case BRIDGE_SN9C102:
            case BRIDGE_SN9C103:
                  err += sn9c102_write_reg(cam, cam->reg[0x18] | 0x80,
                                     0x18);
                  break;
            case BRIDGE_SN9C105:
            case BRIDGE_SN9C120:
                  err += sn9c102_write_reg(cam, cam->reg[0x18] & 0x7f,
                                     0x18);
                  break;
            }
      } else {
            switch (cam->bridge) {
            case BRIDGE_SN9C101:
            case BRIDGE_SN9C102:
            case BRIDGE_SN9C103:
                  err += sn9c102_write_reg(cam, cam->reg[0x18] & 0x7f,
                                     0x18);
                  break;
            case BRIDGE_SN9C105:
            case BRIDGE_SN9C120:
                  err += sn9c102_write_reg(cam, cam->reg[0x18] | 0x80,
                                     0x18);
                  break;
            }
      }

      return err ? -EIO : 0;
}


static int
sn9c102_set_compression(struct sn9c102_device* cam,
                  struct v4l2_jpegcompression* compression)
{
      int i, err = 0;

      switch (cam->bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
      case BRIDGE_SN9C103:
            if (compression->quality == 0)
                  err += sn9c102_write_reg(cam, cam->reg[0x17] | 0x01,
                                     0x17);
            else if (compression->quality == 1)
                  err += sn9c102_write_reg(cam, cam->reg[0x17] & 0xfe,
                                     0x17);
            break;
      case BRIDGE_SN9C105:
      case BRIDGE_SN9C120:
            if (compression->quality == 0) {
                  for (i = 0; i <= 63; i++) {
                        err += sn9c102_write_reg(cam,
                                           SN9C102_Y_QTABLE1[i],
                                           0x100 + i);
                        err += sn9c102_write_reg(cam,
                                           SN9C102_UV_QTABLE1[i],
                                           0x140 + i);
                  }
                  err += sn9c102_write_reg(cam, cam->reg[0x18] & 0xbf,
                                     0x18);
            } else if (compression->quality == 1) {
                  for (i = 0; i <= 63; i++) {
                        err += sn9c102_write_reg(cam,
                                           SN9C102_Y_QTABLE1[i],
                                           0x100 + i);
                        err += sn9c102_write_reg(cam,
                                           SN9C102_UV_QTABLE1[i],
                                           0x140 + i);
                  }
                  err += sn9c102_write_reg(cam, cam->reg[0x18] | 0x40,
                                     0x18);
            }
            break;
      }

      return err ? -EIO : 0;
}


static int sn9c102_set_scale(struct sn9c102_device* cam, u8 scale)
{
      u8 r = 0;
      int err = 0;

      if (scale == 1)
            r = cam->reg[0x18] & 0xcf;
      else if (scale == 2) {
            r = cam->reg[0x18] & 0xcf;
            r |= 0x10;
      } else if (scale == 4)
            r = cam->reg[0x18] | 0x20;

      err += sn9c102_write_reg(cam, r, 0x18);
      if (err)
            return -EIO;

      PDBGG("Scaling factor: %u", scale);

      return 0;
}


static int sn9c102_set_crop(struct sn9c102_device* cam, struct v4l2_rect* rect)
{
      struct sn9c102_sensor* s = &cam->sensor;
      u8 h_start = (u8)(rect->left - s->cropcap.bounds.left),
         v_start = (u8)(rect->top - s->cropcap.bounds.top),
         h_size = (u8)(rect->width / 16),
         v_size = (u8)(rect->height / 16);
      int err = 0;

      err += sn9c102_write_reg(cam, h_start, 0x12);
      err += sn9c102_write_reg(cam, v_start, 0x13);
      err += sn9c102_write_reg(cam, h_size, 0x15);
      err += sn9c102_write_reg(cam, v_size, 0x16);
      if (err)
            return -EIO;

      PDBGG("h_start, v_start, h_size, v_size, ho_size, vo_size "
            "%u %u %u %u", h_start, v_start, h_size, v_size);

      return 0;
}


static int sn9c102_init(struct sn9c102_device* cam)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_control ctrl;
      struct v4l2_queryctrl *qctrl;
      struct v4l2_rect* rect;
      u8 i = 0;
      int err = 0;

      if (!(cam->state & DEV_INITIALIZED)) {
            mutex_init(&cam->open_mutex);
            init_waitqueue_head(&cam->wait_open);
            qctrl = s->qctrl;
            rect = &(s->cropcap.defrect);
      } else { /* use current values */
            qctrl = s->_qctrl;
            rect = &(s->_rect);
      }

      err += sn9c102_set_scale(cam, rect->width / s->pix_format.width);
      err += sn9c102_set_crop(cam, rect);
      if (err)
            return err;

      if (s->init) {
            err = s->init(cam);
            if (err) {
                  DBG(3, "Sensor initialization failed");
                  return err;
            }
      }

      if (!(cam->state & DEV_INITIALIZED))
            if (cam->bridge == BRIDGE_SN9C101 ||
                cam->bridge == BRIDGE_SN9C102 ||
                cam->bridge == BRIDGE_SN9C103) {
                  if (s->pix_format.pixelformat == V4L2_PIX_FMT_JPEG)
                        s->pix_format.pixelformat= V4L2_PIX_FMT_SBGGR8;
                  cam->compression.quality =  cam->reg[0x17] & 0x01 ?
                                        0 : 1;
            } else {
                  if (s->pix_format.pixelformat == V4L2_PIX_FMT_SN9C10X)
                        s->pix_format.pixelformat = V4L2_PIX_FMT_JPEG;
                  cam->compression.quality =  cam->reg[0x18] & 0x40 ?
                                        0 : 1;
                  err += sn9c102_set_compression(cam, &cam->compression);
            }
      else
            err += sn9c102_set_compression(cam, &cam->compression);
      err += sn9c102_set_pix_format(cam, &s->pix_format);
      if (s->set_pix_format)
            err += s->set_pix_format(cam, &s->pix_format);
      if (err)
            return err;

      if (s->pix_format.pixelformat == V4L2_PIX_FMT_SN9C10X ||
          s->pix_format.pixelformat == V4L2_PIX_FMT_JPEG)
            DBG(3, "Compressed video format is active, quality %d",
                cam->compression.quality);
      else
            DBG(3, "Uncompressed video format is active");

      if (s->set_crop)
            if ((err = s->set_crop(cam, rect))) {
                  DBG(3, "set_crop() failed");
                  return err;
            }

      if (s->set_ctrl) {
            for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
                  if (s->qctrl[i].id != 0 &&
                      !(s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)) {
                        ctrl.id = s->qctrl[i].id;
                        ctrl.value = qctrl[i].default_value;
                        err = s->set_ctrl(cam, &ctrl);
                        if (err) {
                              DBG(3, "Set %s control failed",
                                  s->qctrl[i].name);
                              return err;
                        }
                        DBG(3, "Image sensor supports '%s' control",
                            s->qctrl[i].name);
                  }
      }

      if (!(cam->state & DEV_INITIALIZED)) {
            mutex_init(&cam->fileop_mutex);
            spin_lock_init(&cam->queue_lock);
            init_waitqueue_head(&cam->wait_frame);
            init_waitqueue_head(&cam->wait_stream);
            cam->nreadbuffers = 2;
            memcpy(s->_qctrl, s->qctrl, sizeof(s->qctrl));
            memcpy(&(s->_rect), &(s->cropcap.defrect),
                   sizeof(struct v4l2_rect));
            cam->state |= DEV_INITIALIZED;
      }

      DBG(2, "Initialization succeeded");
      return 0;
}

/*****************************************************************************/

static void sn9c102_release_resources(struct kref *kref)
{
      struct sn9c102_device *cam;

      mutex_lock(&sn9c102_sysfs_lock);

      cam = container_of(kref, struct sn9c102_device, kref);

      DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
      video_set_drvdata(cam->v4ldev, NULL);
      video_unregister_device(cam->v4ldev);
      usb_put_dev(cam->usbdev);
      kfree(cam->control_buffer);
      kfree(cam);

      mutex_unlock(&sn9c102_sysfs_lock);

}


static int sn9c102_open(struct inode* inode, struct file* filp)
{
      struct sn9c102_device* cam;
      int err = 0;

      /*
         A read_trylock() in open() is the only safe way to prevent race
         conditions with disconnect(), one close() and multiple (not
         necessarily simultaneous) attempts to open(). For example, it
         prevents from waiting for a second access, while the device
         structure is being deallocated, after a possible disconnect() and
         during a following close() holding the write lock: given that, after
         this deallocation, no access will be possible anymore, using the
         non-trylock version would have let open() gain the access to the
         device structure improperly.
         For this reason the lock must also not be per-device.
      */
      if (!down_read_trylock(&sn9c102_dev_lock))
            return -ERESTARTSYS;

      cam = video_get_drvdata(video_devdata(filp));

      if (wait_for_completion_interruptible(&cam->probe)) {
            up_read(&sn9c102_dev_lock);
            return -ERESTARTSYS;
      }

      kref_get(&cam->kref);

      /*
          Make sure to isolate all the simultaneous opens.
      */
      if (mutex_lock_interruptible(&cam->open_mutex)) {
            kref_put(&cam->kref, sn9c102_release_resources);
            up_read(&sn9c102_dev_lock);
            return -ERESTARTSYS;
      }

      if (cam->state & DEV_DISCONNECTED) {
            DBG(1, "Device not present");
            err = -ENODEV;
            goto out;
      }

      if (cam->users) {
            DBG(2, "Device /dev/video%d is already in use",
                   cam->v4ldev->minor);
            DBG(3, "Simultaneous opens are not supported");
            /*
               open() must follow the open flags and should block
               eventually while the device is in use.
            */
            if ((filp->f_flags & O_NONBLOCK) ||
                (filp->f_flags & O_NDELAY)) {
                  err = -EWOULDBLOCK;
                  goto out;
            }
            DBG(2, "A blocking open() has been requested. Wait for the "
                   "device to be released...");
            up_read(&sn9c102_dev_lock);
            /*
               We will not release the "open_mutex" lock, so that only one
               process can be in the wait queue below. This way the process
               will be sleeping while holding the lock, without loosing its
               priority after any wake_up().
            */
            err = wait_event_interruptible_exclusive(cam->wait_open,
                                    (cam->state & DEV_DISCONNECTED)
                                           || !cam->users);
            down_read(&sn9c102_dev_lock);
            if (err)
                  goto out;
            if (cam->state & DEV_DISCONNECTED) {
                  err = -ENODEV;
                  goto out;
            }
      }

      if (cam->state & DEV_MISCONFIGURED) {
            err = sn9c102_init(cam);
            if (err) {
                  DBG(1, "Initialization failed again. "
                         "I will retry on next open().");
                  goto out;
            }
            cam->state &= ~DEV_MISCONFIGURED;
      }

      if ((err = sn9c102_start_transfer(cam)))
            goto out;

      filp->private_data = cam;
      cam->users++;
      cam->io = IO_NONE;
      cam->stream = STREAM_OFF;
      cam->nbuffers = 0;
      cam->frame_count = 0;
      sn9c102_empty_framequeues(cam);

      DBG(3, "Video device /dev/video%d is open", cam->v4ldev->minor);

out:
      mutex_unlock(&cam->open_mutex);
      if (err)
            kref_put(&cam->kref, sn9c102_release_resources);

      up_read(&sn9c102_dev_lock);
      return err;
}


static int sn9c102_release(struct inode* inode, struct file* filp)
{
      struct sn9c102_device* cam;

      down_write(&sn9c102_dev_lock);

      cam = video_get_drvdata(video_devdata(filp));

      sn9c102_stop_transfer(cam);
      sn9c102_release_buffers(cam);
      cam->users--;
      wake_up_interruptible_nr(&cam->wait_open, 1);

      DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);

      kref_put(&cam->kref, sn9c102_release_resources);

      up_write(&sn9c102_dev_lock);

      return 0;
}


static ssize_t
sn9c102_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
{
      struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));
      struct sn9c102_frame_t* f, * i;
      unsigned long lock_flags;
      long timeout;
      int err = 0;

      if (mutex_lock_interruptible(&cam->fileop_mutex))
            return -ERESTARTSYS;

      if (cam->state & DEV_DISCONNECTED) {
            DBG(1, "Device not present");
            mutex_unlock(&cam->fileop_mutex);
            return -ENODEV;
      }

      if (cam->state & DEV_MISCONFIGURED) {
            DBG(1, "The camera is misconfigured. Close and open it "
                   "again.");
            mutex_unlock(&cam->fileop_mutex);
            return -EIO;
      }

      if (cam->io == IO_MMAP) {
            DBG(3, "Close and open the device again to choose "
                   "the read method");
            mutex_unlock(&cam->fileop_mutex);
            return -EBUSY;
      }

      if (cam->io == IO_NONE) {
            if (!sn9c102_request_buffers(cam,cam->nreadbuffers, IO_READ)) {
                  DBG(1, "read() failed, not enough memory");
                  mutex_unlock(&cam->fileop_mutex);
                  return -ENOMEM;
            }
            cam->io = IO_READ;
            cam->stream = STREAM_ON;
      }

      if (list_empty(&cam->inqueue)) {
            if (!list_empty(&cam->outqueue))
                  sn9c102_empty_framequeues(cam);
            sn9c102_queue_unusedframes(cam);
      }

      if (!count) {
            mutex_unlock(&cam->fileop_mutex);
            return 0;
      }

      if (list_empty(&cam->outqueue)) {
            if (filp->f_flags & O_NONBLOCK) {
                  mutex_unlock(&cam->fileop_mutex);
                  return -EAGAIN;
            }
            if (!cam->module_param.frame_timeout) {
                  err = wait_event_interruptible
                        ( cam->wait_frame,
                        (!list_empty(&cam->outqueue)) ||
                        (cam->state & DEV_DISCONNECTED) ||
                        (cam->state & DEV_MISCONFIGURED) );
                  if (err) {
                        mutex_unlock(&cam->fileop_mutex);
                        return err;
                  }
            } else {
                  timeout = wait_event_interruptible_timeout
                          ( cam->wait_frame,
                            (!list_empty(&cam->outqueue)) ||
                            (cam->state & DEV_DISCONNECTED) ||
                            (cam->state & DEV_MISCONFIGURED),
                            cam->module_param.frame_timeout *
                            1000 * msecs_to_jiffies(1) );
                  if (timeout < 0) {
                        mutex_unlock(&cam->fileop_mutex);
                        return timeout;
                  } else if (timeout == 0 &&
                           !(cam->state & DEV_DISCONNECTED)) {
                        DBG(1, "Video frame timeout elapsed");
                        mutex_unlock(&cam->fileop_mutex);
                        return -EIO;
                  }
            }
            if (cam->state & DEV_DISCONNECTED) {
                  mutex_unlock(&cam->fileop_mutex);
                  return -ENODEV;
            }
            if (cam->state & DEV_MISCONFIGURED) {
                  mutex_unlock(&cam->fileop_mutex);
                  return -EIO;
            }
      }

      f = list_entry(cam->outqueue.prev, struct sn9c102_frame_t, frame);

      if (count > f->buf.bytesused)
            count = f->buf.bytesused;

      if (copy_to_user(buf, f->bufmem, count)) {
            err = -EFAULT;
            goto exit;
      }
      *f_pos += count;

exit:
      spin_lock_irqsave(&cam->queue_lock, lock_flags);
      list_for_each_entry(i, &cam->outqueue, frame)
            i->state = F_UNUSED;
      INIT_LIST_HEAD(&cam->outqueue);
      spin_unlock_irqrestore(&cam->queue_lock, lock_flags);

      sn9c102_queue_unusedframes(cam);

      PDBGG("Frame #%lu, bytes read: %zu",
            (unsigned long)f->buf.index, count);

      mutex_unlock(&cam->fileop_mutex);

      return count;
}


static unsigned int sn9c102_poll(struct file *filp, poll_table *wait)
{
      struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));
      struct sn9c102_frame_t* f;
      unsigned long lock_flags;
      unsigned int mask = 0;

      if (mutex_lock_interruptible(&cam->fileop_mutex))
            return POLLERR;

      if (cam->state & DEV_DISCONNECTED) {
            DBG(1, "Device not present");
            goto error;
      }

      if (cam->state & DEV_MISCONFIGURED) {
            DBG(1, "The camera is misconfigured. Close and open it "
                   "again.");
            goto error;
      }

      if (cam->io == IO_NONE) {
            if (!sn9c102_request_buffers(cam, cam->nreadbuffers,
                                   IO_READ)) {
                  DBG(1, "poll() failed, not enough memory");
                  goto error;
            }
            cam->io = IO_READ;
            cam->stream = STREAM_ON;
      }

      if (cam->io == IO_READ) {
            spin_lock_irqsave(&cam->queue_lock, lock_flags);
            list_for_each_entry(f, &cam->outqueue, frame)
                  f->state = F_UNUSED;
            INIT_LIST_HEAD(&cam->outqueue);
            spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
            sn9c102_queue_unusedframes(cam);
      }

      poll_wait(filp, &cam->wait_frame, wait);

      if (!list_empty(&cam->outqueue))
            mask |= POLLIN | POLLRDNORM;

      mutex_unlock(&cam->fileop_mutex);

      return mask;

error:
      mutex_unlock(&cam->fileop_mutex);
      return POLLERR;
}


static void sn9c102_vm_open(struct vm_area_struct* vma)
{
      struct sn9c102_frame_t* f = vma->vm_private_data;
      f->vma_use_count++;
}


static void sn9c102_vm_close(struct vm_area_struct* vma)
{
      /* NOTE: buffers are not freed here */
      struct sn9c102_frame_t* f = vma->vm_private_data;
      f->vma_use_count--;
}


static struct vm_operations_struct sn9c102_vm_ops = {
      .open = sn9c102_vm_open,
      .close = sn9c102_vm_close,
};


static int sn9c102_mmap(struct file* filp, struct vm_area_struct *vma)
{
      struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));
      unsigned long size = vma->vm_end - vma->vm_start,
                  start = vma->vm_start;
      void *pos;
      u32 i;

      if (mutex_lock_interruptible(&cam->fileop_mutex))
            return -ERESTARTSYS;

      if (cam->state & DEV_DISCONNECTED) {
            DBG(1, "Device not present");
            mutex_unlock(&cam->fileop_mutex);
            return -ENODEV;
      }

      if (cam->state & DEV_MISCONFIGURED) {
            DBG(1, "The camera is misconfigured. Close and open it "
                   "again.");
            mutex_unlock(&cam->fileop_mutex);
            return -EIO;
      }

      if (!(vma->vm_flags & (VM_WRITE | VM_READ))) {
            mutex_unlock(&cam->fileop_mutex);
            return -EACCES;
      }

      if (cam->io != IO_MMAP ||
          size != PAGE_ALIGN(cam->frame[0].buf.length)) {
            mutex_unlock(&cam->fileop_mutex);
            return -EINVAL;
      }

      for (i = 0; i < cam->nbuffers; i++) {
            if ((cam->frame[i].buf.m.offset>>PAGE_SHIFT) == vma->vm_pgoff)
                  break;
      }
      if (i == cam->nbuffers) {
            mutex_unlock(&cam->fileop_mutex);
            return -EINVAL;
      }

      vma->vm_flags |= VM_IO;
      vma->vm_flags |= VM_RESERVED;

      pos = cam->frame[i].bufmem;
      while (size > 0) { /* size is page-aligned */
            if (vm_insert_page(vma, start, vmalloc_to_page(pos))) {
                  mutex_unlock(&cam->fileop_mutex);
                  return -EAGAIN;
            }
            start += PAGE_SIZE;
            pos += PAGE_SIZE;
            size -= PAGE_SIZE;
      }

      vma->vm_ops = &sn9c102_vm_ops;
      vma->vm_private_data = &cam->frame[i];
      sn9c102_vm_open(vma);

      mutex_unlock(&cam->fileop_mutex);

      return 0;
}

/*****************************************************************************/

static int
sn9c102_vidioc_querycap(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_capability cap = {
            .driver = "sn9c102",
            .version = SN9C102_MODULE_VERSION_CODE,
            .capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
                        V4L2_CAP_STREAMING,
      };

      strlcpy(cap.card, cam->v4ldev->name, sizeof(cap.card));
      if (usb_make_path(cam->usbdev, cap.bus_info, sizeof(cap.bus_info)) < 0)
            strlcpy(cap.bus_info, cam->usbdev->dev.bus_id,
                  sizeof(cap.bus_info));

      if (copy_to_user(arg, &cap, sizeof(cap)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_enuminput(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_input i;

      if (copy_from_user(&i, arg, sizeof(i)))
            return -EFAULT;

      if (i.index)
            return -EINVAL;

      memset(&i, 0, sizeof(i));
      strcpy(i.name, "Camera");
      i.type = V4L2_INPUT_TYPE_CAMERA;

      if (copy_to_user(arg, &i, sizeof(i)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_g_input(struct sn9c102_device* cam, void __user * arg)
{
      int index = 0;

      if (copy_to_user(arg, &index, sizeof(index)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_s_input(struct sn9c102_device* cam, void __user * arg)
{
      int index;

      if (copy_from_user(&index, arg, sizeof(index)))
            return -EFAULT;

      if (index != 0)
            return -EINVAL;

      return 0;
}


static int
sn9c102_vidioc_query_ctrl(struct sn9c102_device* cam, void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_queryctrl qc;
      u8 i;

      if (copy_from_user(&qc, arg, sizeof(qc)))
            return -EFAULT;

      for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
            if (qc.id && qc.id == s->qctrl[i].id) {
                  memcpy(&qc, &(s->qctrl[i]), sizeof(qc));
                  if (copy_to_user(arg, &qc, sizeof(qc)))
                        return -EFAULT;
                  return 0;
            }

      return -EINVAL;
}


static int
sn9c102_vidioc_g_ctrl(struct sn9c102_device* cam, void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_control ctrl;
      int err = 0;
      u8 i;

      if (!s->get_ctrl && !s->set_ctrl)
            return -EINVAL;

      if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
            return -EFAULT;

      if (!s->get_ctrl) {
            for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
                  if (ctrl.id && ctrl.id == s->qctrl[i].id) {
                        ctrl.value = s->_qctrl[i].default_value;
                        goto exit;
                  }
            return -EINVAL;
      } else
            err = s->get_ctrl(cam, &ctrl);

exit:
      if (copy_to_user(arg, &ctrl, sizeof(ctrl)))
            return -EFAULT;

      PDBGG("VIDIOC_G_CTRL: id %lu, value %lu",
            (unsigned long)ctrl.id, (unsigned long)ctrl.value);

      return err;
}


static int
sn9c102_vidioc_s_ctrl(struct sn9c102_device* cam, void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_control ctrl;
      u8 i;
      int err = 0;

      if (!s->set_ctrl)
            return -EINVAL;

      if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
            return -EFAULT;

      for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
            if (ctrl.id == s->qctrl[i].id) {
                  if (s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)
                        return -EINVAL;
                  if (ctrl.value < s->qctrl[i].minimum ||
                      ctrl.value > s->qctrl[i].maximum)
                        return -ERANGE;
                  ctrl.value -= ctrl.value % s->qctrl[i].step;
                  break;
            }

      if ((err = s->set_ctrl(cam, &ctrl)))
            return err;

      s->_qctrl[i].default_value = ctrl.value;

      PDBGG("VIDIOC_S_CTRL: id %lu, value %lu",
            (unsigned long)ctrl.id, (unsigned long)ctrl.value);

      return 0;
}


static int
sn9c102_vidioc_cropcap(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_cropcap* cc = &(cam->sensor.cropcap);

      cc->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
      cc->pixelaspect.numerator = 1;
      cc->pixelaspect.denominator = 1;

      if (copy_to_user(arg, cc, sizeof(*cc)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_g_crop(struct sn9c102_device* cam, void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_crop crop = {
            .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
      };

      memcpy(&(crop.c), &(s->_rect), sizeof(struct v4l2_rect));

      if (copy_to_user(arg, &crop, sizeof(crop)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_s_crop(struct sn9c102_device* cam, void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_crop crop;
      struct v4l2_rect* rect;
      struct v4l2_rect* bounds = &(s->cropcap.bounds);
      struct v4l2_pix_format* pix_format = &(s->pix_format);
      u8 scale;
      const enum sn9c102_stream_state stream = cam->stream;
      const u32 nbuffers = cam->nbuffers;
      u32 i;
      int err = 0;

      if (copy_from_user(&crop, arg, sizeof(crop)))
            return -EFAULT;

      rect = &(crop.c);

      if (crop.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      if (cam->module_param.force_munmap)
            for (i = 0; i < cam->nbuffers; i++)
                  if (cam->frame[i].vma_use_count) {
                        DBG(3, "VIDIOC_S_CROP failed. "
                               "Unmap the buffers first.");
                        return -EBUSY;
                  }

      /* Preserve R,G or B origin */
      rect->left = (s->_rect.left & 1L) ? rect->left | 1L : rect->left & ~1L;
      rect->top = (s->_rect.top & 1L) ? rect->top | 1L : rect->top & ~1L;

      if (rect->width < 16)
            rect->width = 16;
      if (rect->height < 16)
            rect->height = 16;
      if (rect->width > bounds->width)
            rect->width = bounds->width;
      if (rect->height > bounds->height)
            rect->height = bounds->height;
      if (rect->left < bounds->left)
            rect->left = bounds->left;
      if (rect->top < bounds->top)
            rect->top = bounds->top;
      if (rect->left + rect->width > bounds->left + bounds->width)
            rect->left = bounds->left+bounds->width - rect->width;
      if (rect->top + rect->height > bounds->top + bounds->height)
            rect->top = bounds->top+bounds->height - rect->height;

      rect->width &= ~15L;
      rect->height &= ~15L;

      if (SN9C102_PRESERVE_IMGSCALE) {
            /* Calculate the actual scaling factor */
            u32 a, b;
            a = rect->width * rect->height;
            b = pix_format->width * pix_format->height;
            scale = b ? (u8)((a / b) < 4 ? 1 : ((a / b) < 16 ? 2 : 4)) : 1;
      } else
            scale = 1;

      if (cam->stream == STREAM_ON)
            if ((err = sn9c102_stream_interrupt(cam)))
                  return err;

      if (copy_to_user(arg, &crop, sizeof(crop))) {
            cam->stream = stream;
            return -EFAULT;
      }

      if (cam->module_param.force_munmap || cam->io == IO_READ)
            sn9c102_release_buffers(cam);

      err = sn9c102_set_crop(cam, rect);
      if (s->set_crop)
            err += s->set_crop(cam, rect);
      err += sn9c102_set_scale(cam, scale);

      if (err) { /* atomic, no rollback in ioctl() */
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "VIDIOC_S_CROP failed because of hardware problems. To "
                   "use the camera, close and open /dev/video%d again.",
                cam->v4ldev->minor);
            return -EIO;
      }

      s->pix_format.width = rect->width/scale;
      s->pix_format.height = rect->height/scale;
      memcpy(&(s->_rect), rect, sizeof(*rect));

      if ((cam->module_param.force_munmap || cam->io == IO_READ) &&
          nbuffers != sn9c102_request_buffers(cam, nbuffers, cam->io)) {
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "VIDIOC_S_CROP failed because of not enough memory. To "
                   "use the camera, close and open /dev/video%d again.",
                cam->v4ldev->minor);
            return -ENOMEM;
      }

      if (cam->io == IO_READ)
            sn9c102_empty_framequeues(cam);
      else if (cam->module_param.force_munmap)
            sn9c102_requeue_outqueue(cam);

      cam->stream = stream;

      return 0;
}


static int
sn9c102_vidioc_enum_framesizes(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_frmsizeenum frmsize;

      if (copy_from_user(&frmsize, arg, sizeof(frmsize)))
            return -EFAULT;

      if (frmsize.index != 0)
            return -EINVAL;

      switch (cam->bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
      case BRIDGE_SN9C103:
            if (frmsize.pixel_format != V4L2_PIX_FMT_SN9C10X &&
                frmsize.pixel_format != V4L2_PIX_FMT_SBGGR8)
                  return -EINVAL;
      case BRIDGE_SN9C105:
      case BRIDGE_SN9C120:
            if (frmsize.pixel_format != V4L2_PIX_FMT_JPEG &&
                frmsize.pixel_format != V4L2_PIX_FMT_SBGGR8)
                  return -EINVAL;
      }

      frmsize.type = V4L2_FRMSIZE_TYPE_STEPWISE;
      frmsize.stepwise.min_width = frmsize.stepwise.step_width = 16;
      frmsize.stepwise.min_height = frmsize.stepwise.step_height = 16;
      frmsize.stepwise.max_width = cam->sensor.cropcap.bounds.width;
      frmsize.stepwise.max_height = cam->sensor.cropcap.bounds.height;
      memset(&frmsize.reserved, 0, sizeof(frmsize.reserved));

      if (copy_to_user(arg, &frmsize, sizeof(frmsize)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_enum_fmt(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_fmtdesc fmtd;

      if (copy_from_user(&fmtd, arg, sizeof(fmtd)))
            return -EFAULT;

      if (fmtd.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      if (fmtd.index == 0) {
            strcpy(fmtd.description, "bayer rgb");
            fmtd.pixelformat = V4L2_PIX_FMT_SBGGR8;
      } else if (fmtd.index == 1) {
            switch (cam->bridge) {
            case BRIDGE_SN9C101:
            case BRIDGE_SN9C102:
            case BRIDGE_SN9C103:
                  strcpy(fmtd.description, "compressed");
                  fmtd.pixelformat = V4L2_PIX_FMT_SN9C10X;
                  break;
            case BRIDGE_SN9C105:
            case BRIDGE_SN9C120:
                  strcpy(fmtd.description, "JPEG");
                  fmtd.pixelformat = V4L2_PIX_FMT_JPEG;
                  break;
            }
            fmtd.flags = V4L2_FMT_FLAG_COMPRESSED;
      } else
            return -EINVAL;

      fmtd.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
      memset(&fmtd.reserved, 0, sizeof(fmtd.reserved));

      if (copy_to_user(arg, &fmtd, sizeof(fmtd)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_g_fmt(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_format format;
      struct v4l2_pix_format* pfmt = &(cam->sensor.pix_format);

      if (copy_from_user(&format, arg, sizeof(format)))
            return -EFAULT;

      if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      pfmt->colorspace = (pfmt->pixelformat == V4L2_PIX_FMT_JPEG) ?
                     V4L2_COLORSPACE_JPEG : V4L2_COLORSPACE_SRGB;
      pfmt->bytesperline = (pfmt->pixelformat == V4L2_PIX_FMT_SN9C10X ||
                        pfmt->pixelformat == V4L2_PIX_FMT_JPEG)
                       ? 0 : (pfmt->width * pfmt->priv) / 8;
      pfmt->sizeimage = pfmt->height * ((pfmt->width*pfmt->priv)/8);
      pfmt->field = V4L2_FIELD_NONE;
      memcpy(&(format.fmt.pix), pfmt, sizeof(*pfmt));

      if (copy_to_user(arg, &format, sizeof(format)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_try_s_fmt(struct sn9c102_device* cam, unsigned int cmd,
                   void __user * arg)
{
      struct sn9c102_sensor* s = &cam->sensor;
      struct v4l2_format format;
      struct v4l2_pix_format* pix;
      struct v4l2_pix_format* pfmt = &(s->pix_format);
      struct v4l2_rect* bounds = &(s->cropcap.bounds);
      struct v4l2_rect rect;
      u8 scale;
      const enum sn9c102_stream_state stream = cam->stream;
      const u32 nbuffers = cam->nbuffers;
      u32 i;
      int err = 0;

      if (copy_from_user(&format, arg, sizeof(format)))
            return -EFAULT;

      pix = &(format.fmt.pix);

      if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      memcpy(&rect, &(s->_rect), sizeof(rect));

      { /* calculate the actual scaling factor */
            u32 a, b;
            a = rect.width * rect.height;
            b = pix->width * pix->height;
            scale = b ? (u8)((a / b) < 4 ? 1 : ((a / b) < 16 ? 2 : 4)) : 1;
      }

      rect.width = scale * pix->width;
      rect.height = scale * pix->height;

      if (rect.width < 16)
            rect.width = 16;
      if (rect.height < 16)
            rect.height = 16;
      if (rect.width > bounds->left + bounds->width - rect.left)
            rect.width = bounds->left + bounds->width - rect.left;
      if (rect.height > bounds->top + bounds->height - rect.top)
            rect.height = bounds->top + bounds->height - rect.top;

      rect.width &= ~15L;
      rect.height &= ~15L;

      { /* adjust the scaling factor */
            u32 a, b;
            a = rect.width * rect.height;
            b = pix->width * pix->height;
            scale = b ? (u8)((a / b) < 4 ? 1 : ((a / b) < 16 ? 2 : 4)) : 1;
      }

      pix->width = rect.width / scale;
      pix->height = rect.height / scale;

      switch (cam->bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
      case BRIDGE_SN9C103:
            if (pix->pixelformat != V4L2_PIX_FMT_SN9C10X &&
                pix->pixelformat != V4L2_PIX_FMT_SBGGR8)
                  pix->pixelformat = pfmt->pixelformat;
            break;
      case BRIDGE_SN9C105:
      case BRIDGE_SN9C120:
            if (pix->pixelformat != V4L2_PIX_FMT_JPEG &&
                pix->pixelformat != V4L2_PIX_FMT_SBGGR8)
                  pix->pixelformat = pfmt->pixelformat;
            break;
      }
      pix->priv = pfmt->priv; /* bpp */
      pix->colorspace = (pix->pixelformat == V4L2_PIX_FMT_JPEG) ?
                    V4L2_COLORSPACE_JPEG : V4L2_COLORSPACE_SRGB;
      pix->bytesperline = (pix->pixelformat == V4L2_PIX_FMT_SN9C10X ||
                       pix->pixelformat == V4L2_PIX_FMT_JPEG)
                      ? 0 : (pix->width * pix->priv) / 8;
      pix->sizeimage = pix->height * ((pix->width * pix->priv) / 8);
      pix->field = V4L2_FIELD_NONE;

      if (cmd == VIDIOC_TRY_FMT) {
            if (copy_to_user(arg, &format, sizeof(format)))
                  return -EFAULT;
            return 0;
      }

      if (cam->module_param.force_munmap)
            for (i = 0; i < cam->nbuffers; i++)
                  if (cam->frame[i].vma_use_count) {
                        DBG(3, "VIDIOC_S_FMT failed. Unmap the "
                               "buffers first.");
                        return -EBUSY;
                  }

      if (cam->stream == STREAM_ON)
            if ((err = sn9c102_stream_interrupt(cam)))
                  return err;

      if (copy_to_user(arg, &format, sizeof(format))) {
            cam->stream = stream;
            return -EFAULT;
      }

      if (cam->module_param.force_munmap  || cam->io == IO_READ)
            sn9c102_release_buffers(cam);

      err += sn9c102_set_pix_format(cam, pix);
      err += sn9c102_set_crop(cam, &rect);
      if (s->set_pix_format)
            err += s->set_pix_format(cam, pix);
      if (s->set_crop)
            err += s->set_crop(cam, &rect);
      err += sn9c102_set_scale(cam, scale);

      if (err) { /* atomic, no rollback in ioctl() */
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "VIDIOC_S_FMT failed because of hardware problems. To "
                   "use the camera, close and open /dev/video%d again.",
                cam->v4ldev->minor);
            return -EIO;
      }

      memcpy(pfmt, pix, sizeof(*pix));
      memcpy(&(s->_rect), &rect, sizeof(rect));

      if ((cam->module_param.force_munmap  || cam->io == IO_READ) &&
          nbuffers != sn9c102_request_buffers(cam, nbuffers, cam->io)) {
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "VIDIOC_S_FMT failed because of not enough memory. To "
                   "use the camera, close and open /dev/video%d again.",
                cam->v4ldev->minor);
            return -ENOMEM;
      }

      if (cam->io == IO_READ)
            sn9c102_empty_framequeues(cam);
      else if (cam->module_param.force_munmap)
            sn9c102_requeue_outqueue(cam);

      cam->stream = stream;

      return 0;
}


static int
sn9c102_vidioc_g_jpegcomp(struct sn9c102_device* cam, void __user * arg)
{
      if (copy_to_user(arg, &cam->compression, sizeof(cam->compression)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_s_jpegcomp(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_jpegcompression jc;
      const enum sn9c102_stream_state stream = cam->stream;
      int err = 0;

      if (copy_from_user(&jc, arg, sizeof(jc)))
            return -EFAULT;

      if (jc.quality != 0 && jc.quality != 1)
            return -EINVAL;

      if (cam->stream == STREAM_ON)
            if ((err = sn9c102_stream_interrupt(cam)))
                  return err;

      err += sn9c102_set_compression(cam, &jc);
      if (err) { /* atomic, no rollback in ioctl() */
            cam->state |= DEV_MISCONFIGURED;
            DBG(1, "VIDIOC_S_JPEGCOMP failed because of hardware "
                   "problems. To use the camera, close and open "
                   "/dev/video%d again.", cam->v4ldev->minor);
            return -EIO;
      }

      cam->compression.quality = jc.quality;

      cam->stream = stream;

      return 0;
}


static int
sn9c102_vidioc_reqbufs(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_requestbuffers rb;
      u32 i;
      int err;

      if (copy_from_user(&rb, arg, sizeof(rb)))
            return -EFAULT;

      if (rb.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
          rb.memory != V4L2_MEMORY_MMAP)
            return -EINVAL;

      if (cam->io == IO_READ) {
            DBG(3, "Close and open the device again to choose the mmap "
                   "I/O method");
            return -EBUSY;
      }

      for (i = 0; i < cam->nbuffers; i++)
            if (cam->frame[i].vma_use_count) {
                  DBG(3, "VIDIOC_REQBUFS failed. Previous buffers are "
                         "still mapped.");
                  return -EBUSY;
            }

      if (cam->stream == STREAM_ON)
            if ((err = sn9c102_stream_interrupt(cam)))
                  return err;

      sn9c102_empty_framequeues(cam);

      sn9c102_release_buffers(cam);
      if (rb.count)
            rb.count = sn9c102_request_buffers(cam, rb.count, IO_MMAP);

      if (copy_to_user(arg, &rb, sizeof(rb))) {
            sn9c102_release_buffers(cam);
            cam->io = IO_NONE;
            return -EFAULT;
      }

      cam->io = rb.count ? IO_MMAP : IO_NONE;

      return 0;
}


static int
sn9c102_vidioc_querybuf(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_buffer b;

      if (copy_from_user(&b, arg, sizeof(b)))
            return -EFAULT;

      if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
          b.index >= cam->nbuffers || cam->io != IO_MMAP)
            return -EINVAL;

      memcpy(&b, &cam->frame[b.index].buf, sizeof(b));

      if (cam->frame[b.index].vma_use_count)
            b.flags |= V4L2_BUF_FLAG_MAPPED;

      if (cam->frame[b.index].state == F_DONE)
            b.flags |= V4L2_BUF_FLAG_DONE;
      else if (cam->frame[b.index].state != F_UNUSED)
            b.flags |= V4L2_BUF_FLAG_QUEUED;

      if (copy_to_user(arg, &b, sizeof(b)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_qbuf(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_buffer b;
      unsigned long lock_flags;

      if (copy_from_user(&b, arg, sizeof(b)))
            return -EFAULT;

      if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
          b.index >= cam->nbuffers || cam->io != IO_MMAP)
            return -EINVAL;

      if (cam->frame[b.index].state != F_UNUSED)
            return -EINVAL;

      cam->frame[b.index].state = F_QUEUED;

      spin_lock_irqsave(&cam->queue_lock, lock_flags);
      list_add_tail(&cam->frame[b.index].frame, &cam->inqueue);
      spin_unlock_irqrestore(&cam->queue_lock, lock_flags);

      PDBGG("Frame #%lu queued", (unsigned long)b.index);

      return 0;
}


static int
sn9c102_vidioc_dqbuf(struct sn9c102_device* cam, struct file* filp,
                 void __user * arg)
{
      struct v4l2_buffer b;
      struct sn9c102_frame_t *f;
      unsigned long lock_flags;
      long timeout;
      int err = 0;

      if (copy_from_user(&b, arg, sizeof(b)))
            return -EFAULT;

      if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
            return -EINVAL;

      if (list_empty(&cam->outqueue)) {
            if (cam->stream == STREAM_OFF)
                  return -EINVAL;
            if (filp->f_flags & O_NONBLOCK)
                  return -EAGAIN;
            if (!cam->module_param.frame_timeout) {
                  err = wait_event_interruptible
                        ( cam->wait_frame,
                        (!list_empty(&cam->outqueue)) ||
                        (cam->state & DEV_DISCONNECTED) ||
                        (cam->state & DEV_MISCONFIGURED) );
                  if (err)
                        return err;
            } else {
                  timeout = wait_event_interruptible_timeout
                          ( cam->wait_frame,
                            (!list_empty(&cam->outqueue)) ||
                            (cam->state & DEV_DISCONNECTED) ||
                            (cam->state & DEV_MISCONFIGURED),
                            cam->module_param.frame_timeout *
                            1000 * msecs_to_jiffies(1) );
                  if (timeout < 0)
                        return timeout;
                  else if (timeout == 0 &&
                         !(cam->state & DEV_DISCONNECTED)) {
                        DBG(1, "Video frame timeout elapsed");
                        return -EIO;
                  }
            }
            if (cam->state & DEV_DISCONNECTED)
                  return -ENODEV;
            if (cam->state & DEV_MISCONFIGURED)
                  return -EIO;
      }

      spin_lock_irqsave(&cam->queue_lock, lock_flags);
      f = list_entry(cam->outqueue.next, struct sn9c102_frame_t, frame);
      list_del(cam->outqueue.next);
      spin_unlock_irqrestore(&cam->queue_lock, lock_flags);

      f->state = F_UNUSED;

      memcpy(&b, &f->buf, sizeof(b));
      if (f->vma_use_count)
            b.flags |= V4L2_BUF_FLAG_MAPPED;

      if (copy_to_user(arg, &b, sizeof(b)))
            return -EFAULT;

      PDBGG("Frame #%lu dequeued", (unsigned long)f->buf.index);

      return 0;
}


static int
sn9c102_vidioc_streamon(struct sn9c102_device* cam, void __user * arg)
{
      int type;

      if (copy_from_user(&type, arg, sizeof(type)))
            return -EFAULT;

      if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
            return -EINVAL;

      cam->stream = STREAM_ON;

      DBG(3, "Stream on");

      return 0;
}


static int
sn9c102_vidioc_streamoff(struct sn9c102_device* cam, void __user * arg)
{
      int type, err;

      if (copy_from_user(&type, arg, sizeof(type)))
            return -EFAULT;

      if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
            return -EINVAL;

      if (cam->stream == STREAM_ON)
            if ((err = sn9c102_stream_interrupt(cam)))
                  return err;

      sn9c102_empty_framequeues(cam);

      DBG(3, "Stream off");

      return 0;
}


static int
sn9c102_vidioc_g_parm(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_streamparm sp;

      if (copy_from_user(&sp, arg, sizeof(sp)))
            return -EFAULT;

      if (sp.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      sp.parm.capture.extendedmode = 0;
      sp.parm.capture.readbuffers = cam->nreadbuffers;

      if (copy_to_user(arg, &sp, sizeof(sp)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_s_parm(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_streamparm sp;

      if (copy_from_user(&sp, arg, sizeof(sp)))
            return -EFAULT;

      if (sp.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
            return -EINVAL;

      sp.parm.capture.extendedmode = 0;

      if (sp.parm.capture.readbuffers == 0)
            sp.parm.capture.readbuffers = cam->nreadbuffers;

      if (sp.parm.capture.readbuffers > SN9C102_MAX_FRAMES)
            sp.parm.capture.readbuffers = SN9C102_MAX_FRAMES;

      if (copy_to_user(arg, &sp, sizeof(sp)))
            return -EFAULT;

      cam->nreadbuffers = sp.parm.capture.readbuffers;

      return 0;
}


static int
sn9c102_vidioc_enumaudio(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_audio audio;

      if (cam->bridge == BRIDGE_SN9C101 || cam->bridge == BRIDGE_SN9C102)
            return -EINVAL;

      if (copy_from_user(&audio, arg, sizeof(audio)))
            return -EFAULT;

      if (audio.index != 0)
            return -EINVAL;

      strcpy(audio.name, "Microphone");
      audio.capability = 0;
      audio.mode = 0;

      if (copy_to_user(arg, &audio, sizeof(audio)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_g_audio(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_audio audio;

      if (cam->bridge == BRIDGE_SN9C101 || cam->bridge == BRIDGE_SN9C102)
            return -EINVAL;

      if (copy_from_user(&audio, arg, sizeof(audio)))
            return -EFAULT;

      memset(&audio, 0, sizeof(audio));
      strcpy(audio.name, "Microphone");

      if (copy_to_user(arg, &audio, sizeof(audio)))
            return -EFAULT;

      return 0;
}


static int
sn9c102_vidioc_s_audio(struct sn9c102_device* cam, void __user * arg)
{
      struct v4l2_audio audio;

      if (cam->bridge == BRIDGE_SN9C101 || cam->bridge == BRIDGE_SN9C102)
            return -EINVAL;

      if (copy_from_user(&audio, arg, sizeof(audio)))
            return -EFAULT;

      if (audio.index != 0)
            return -EINVAL;

      return 0;
}


static int sn9c102_ioctl_v4l2(struct inode* inode, struct file* filp,
                        unsigned int cmd, void __user * arg)
{
      struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));

      switch (cmd) {

      case VIDIOC_QUERYCAP:
            return sn9c102_vidioc_querycap(cam, arg);

      case VIDIOC_ENUMINPUT:
            return sn9c102_vidioc_enuminput(cam, arg);

      case VIDIOC_G_INPUT:
            return sn9c102_vidioc_g_input(cam, arg);

      case VIDIOC_S_INPUT:
            return sn9c102_vidioc_s_input(cam, arg);

      case VIDIOC_QUERYCTRL:
            return sn9c102_vidioc_query_ctrl(cam, arg);

      case VIDIOC_G_CTRL:
            return sn9c102_vidioc_g_ctrl(cam, arg);

      case VIDIOC_S_CTRL:
            return sn9c102_vidioc_s_ctrl(cam, arg);

      case VIDIOC_CROPCAP:
            return sn9c102_vidioc_cropcap(cam, arg);

      case VIDIOC_G_CROP:
            return sn9c102_vidioc_g_crop(cam, arg);

      case VIDIOC_S_CROP:
            return sn9c102_vidioc_s_crop(cam, arg);

      case VIDIOC_ENUM_FRAMESIZES:
            return sn9c102_vidioc_enum_framesizes(cam, arg);

      case VIDIOC_ENUM_FMT:
            return sn9c102_vidioc_enum_fmt(cam, arg);

      case VIDIOC_G_FMT:
            return sn9c102_vidioc_g_fmt(cam, arg);

      case VIDIOC_TRY_FMT:
      case VIDIOC_S_FMT:
            return sn9c102_vidioc_try_s_fmt(cam, cmd, arg);

      case VIDIOC_G_JPEGCOMP:
            return sn9c102_vidioc_g_jpegcomp(cam, arg);

      case VIDIOC_S_JPEGCOMP:
            return sn9c102_vidioc_s_jpegcomp(cam, arg);

      case VIDIOC_REQBUFS:
            return sn9c102_vidioc_reqbufs(cam, arg);

      case VIDIOC_QUERYBUF:
            return sn9c102_vidioc_querybuf(cam, arg);

      case VIDIOC_QBUF:
            return sn9c102_vidioc_qbuf(cam, arg);

      case VIDIOC_DQBUF:
            return sn9c102_vidioc_dqbuf(cam, filp, arg);

      case VIDIOC_STREAMON:
            return sn9c102_vidioc_streamon(cam, arg);

      case VIDIOC_STREAMOFF:
            return sn9c102_vidioc_streamoff(cam, arg);

      case VIDIOC_G_PARM:
            return sn9c102_vidioc_g_parm(cam, arg);

      case VIDIOC_S_PARM:
            return sn9c102_vidioc_s_parm(cam, arg);

      case VIDIOC_ENUMAUDIO:
            return sn9c102_vidioc_enumaudio(cam, arg);

      case VIDIOC_G_AUDIO:
            return sn9c102_vidioc_g_audio(cam, arg);

      case VIDIOC_S_AUDIO:
            return sn9c102_vidioc_s_audio(cam, arg);

      case VIDIOC_G_STD:
      case VIDIOC_S_STD:
      case VIDIOC_QUERYSTD:
      case VIDIOC_ENUMSTD:
      case VIDIOC_QUERYMENU:
      case VIDIOC_ENUM_FRAMEINTERVALS:
            return -EINVAL;

      default:
            return -EINVAL;

      }
}


static int sn9c102_ioctl(struct inode* inode, struct file* filp,
                   unsigned int cmd, unsigned long arg)
{
      struct sn9c102_device* cam = video_get_drvdata(video_devdata(filp));
      int err = 0;

      if (mutex_lock_interruptible(&cam->fileop_mutex))
            return -ERESTARTSYS;

      if (cam->state & DEV_DISCONNECTED) {
            DBG(1, "Device not present");
            mutex_unlock(&cam->fileop_mutex);
            return -ENODEV;
      }

      if (cam->state & DEV_MISCONFIGURED) {
            DBG(1, "The camera is misconfigured. Close and open it "
                   "again.");
            mutex_unlock(&cam->fileop_mutex);
            return -EIO;
      }

      V4LDBG(3, "sn9c102", cmd);

      err = sn9c102_ioctl_v4l2(inode, filp, cmd, (void __user *)arg);

      mutex_unlock(&cam->fileop_mutex);

      return err;
}

/*****************************************************************************/

static const struct file_operations sn9c102_fops = {
      .owner = THIS_MODULE,
      .open = sn9c102_open,
      .release = sn9c102_release,
      .ioctl = sn9c102_ioctl,
      .compat_ioctl = v4l_compat_ioctl32,
      .read = sn9c102_read,
      .poll = sn9c102_poll,
      .mmap = sn9c102_mmap,
      .llseek = no_llseek,
};

/*****************************************************************************/

/* It exists a single interface only. We do not need to validate anything. */
static int
sn9c102_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
{
      struct usb_device *udev = interface_to_usbdev(intf);
      struct sn9c102_device* cam;
      static unsigned int dev_nr = 0;
      unsigned int i;
      int err = 0, r;

      if (!(cam = kzalloc(sizeof(struct sn9c102_device), GFP_KERNEL)))
            return -ENOMEM;

      cam->usbdev = udev;

      if (!(cam->control_buffer = kzalloc(8, GFP_KERNEL))) {
            DBG(1, "kzalloc() failed");
            err = -ENOMEM;
            goto fail;
      }

      if (!(cam->v4ldev = video_device_alloc())) {
            DBG(1, "video_device_alloc() failed");
            err = -ENOMEM;
            goto fail;
      }

      r = sn9c102_read_reg(cam, 0x00);
      if (r < 0 || (r != 0x10 && r != 0x11 && r != 0x12)) {
            DBG(1, "Sorry, this is not a SN9C1xx-based camera "
                   "(vid:pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
            err = -ENODEV;
            goto fail;
      }

      cam->bridge = id->driver_info;
      switch (cam->bridge) {
      case BRIDGE_SN9C101:
      case BRIDGE_SN9C102:
            DBG(2, "SN9C10[12] PC Camera Controller detected "
                   "(vid:pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
            break;
      case BRIDGE_SN9C103:
            DBG(2, "SN9C103 PC Camera Controller detected "
                   "(vid:pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
            break;
      case BRIDGE_SN9C105:
            DBG(2, "SN9C105 PC Camera Controller detected "
                   "(vid:pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
            break;
      case BRIDGE_SN9C120:
            DBG(2, "SN9C120 PC Camera Controller detected "
                   "(vid:pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);
            break;
      }

      for  (i = 0; i < ARRAY_SIZE(sn9c102_sensor_table); i++) {
            err = sn9c102_sensor_table[i](cam);
            if (!err)
                  break;
      }

      if (!err) {
            DBG(2, "%s image sensor detected", cam->sensor.name);
            DBG(3, "Support for %s maintained by %s",
                cam->sensor.name, cam->sensor.maintainer);
      } else {
            DBG(1, "No supported image sensor detected for this bridge");
            err = -ENODEV;
            goto fail;
      }

      if (!(cam->bridge & cam->sensor.supported_bridge)) {
            DBG(1, "Bridge not supported");
            err = -ENODEV;
            goto fail;
      }

      if (sn9c102_init(cam)) {
            DBG(1, "Initialization failed. I will retry on open().");
            cam->state |= DEV_MISCONFIGURED;
      }

      strcpy(cam->v4ldev->name, "SN9C1xx PC Camera");
      cam->v4ldev->owner = THIS_MODULE;
      cam->v4ldev->type = VID_TYPE_CAPTURE | VID_TYPE_SCALES;
      cam->v4ldev->fops = &sn9c102_fops;
      cam->v4ldev->minor = video_nr[dev_nr];
      cam->v4ldev->release = video_device_release;
      video_set_drvdata(cam->v4ldev, cam);

      init_completion(&cam->probe);

      err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
                            video_nr[dev_nr]);
      if (err) {
            DBG(1, "V4L2 device registration failed");
            if (err == -ENFILE && video_nr[dev_nr] == -1)
                  DBG(1, "Free /dev/videoX node not found");
            video_nr[dev_nr] = -1;
            dev_nr = (dev_nr < SN9C102_MAX_DEVICES-1) ? dev_nr+1 : 0;
            complete_all(&cam->probe);
            goto fail;
      }

      DBG(2, "V4L2 device registered as /dev/video%d", cam->v4ldev->minor);

      cam->module_param.force_munmap = force_munmap[dev_nr];
      cam->module_param.frame_timeout = frame_timeout[dev_nr];

      dev_nr = (dev_nr < SN9C102_MAX_DEVICES-1) ? dev_nr+1 : 0;

#ifdef CONFIG_VIDEO_ADV_DEBUG
      err = sn9c102_create_sysfs(cam);
      if (!err)
            DBG(2, "Optional device control through 'sysfs' "
                   "interface ready");
      else
            DBG(2, "Failed to create optional 'sysfs' interface for "
                   "device controlling. Error #%d", err);
#else
      DBG(2, "Optional device control through 'sysfs' interface disabled");
      DBG(3, "Compile the kernel with the 'CONFIG_VIDEO_ADV_DEBUG' "
             "configuration option to enable it.");
#endif

      usb_set_intfdata(intf, cam);
      kref_init(&cam->kref);
      usb_get_dev(cam->usbdev);

      complete_all(&cam->probe);

      return 0;

fail:
      if (cam) {
            kfree(cam->control_buffer);
            if (cam->v4ldev)
                  video_device_release(cam->v4ldev);
            kfree(cam);
      }
      return err;
}


static void sn9c102_usb_disconnect(struct usb_interface* intf)
{
      struct sn9c102_device* cam;

      down_write(&sn9c102_dev_lock);

      cam = usb_get_intfdata(intf);

      DBG(2, "Disconnecting %s...", cam->v4ldev->name);

      if (cam->users) {
            DBG(2, "Device /dev/video%d is open! Deregistration and "
                   "memory deallocation are deferred.",
                cam->v4ldev->minor);
            cam->state |= DEV_MISCONFIGURED;
            sn9c102_stop_transfer(cam);
            cam->state |= DEV_DISCONNECTED;
            wake_up_interruptible(&cam->wait_frame);
            wake_up(&cam->wait_stream);
      } else
            cam->state |= DEV_DISCONNECTED;

      wake_up_interruptible_all(&cam->wait_open);

      kref_put(&cam->kref, sn9c102_release_resources);

      up_write(&sn9c102_dev_lock);
}


static struct usb_driver sn9c102_usb_driver = {
      .name =       "sn9c102",
      .id_table =   sn9c102_id_table,
      .probe =      sn9c102_usb_probe,
      .disconnect = sn9c102_usb_disconnect,
};

/*****************************************************************************/

static int __init sn9c102_module_init(void)
{
      int err = 0;

      KDBG(2, SN9C102_MODULE_NAME " v" SN9C102_MODULE_VERSION);
      KDBG(3, SN9C102_MODULE_AUTHOR);

      if ((err = usb_register(&sn9c102_usb_driver)))
            KDBG(1, "usb_register() failed");

      return err;
}


static void __exit sn9c102_module_exit(void)
{
      usb_deregister(&sn9c102_usb_driver);
}


module_init(sn9c102_module_init);
module_exit(sn9c102_module_exit);

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