/***************************************************************************
 * Video4Linux driver for W996[87]CF JPEG USB Dual Mode Camera Chip.       *
 *                                                                         *
 * Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>  *
 *                                                                         *
 * - Memory management code from bttv driver by Ralph Metzler,             *
 *   Marcus Metzler and Gerd Knorr.                                        *
 * - I2C interface to kernel, high-level image sensor control routines and *
 *   some symbolic names from OV511 driver by Mark W. McClelland.          *
 * - Low-level I2C fast write function by Piotr Czerczak.                  *
 * - Low-level I2C read function by Frederic Jouault.                      *
 *                                                                         *
 * 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/kernel.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/ioctl.h>
#include <linux/delay.h>
#include <linux/stddef.h>
#include <asm/page.h>
#include <asm/uaccess.h>
#include <linux/page-flags.h>
#include <media/v4l2-ioctl.h>

#include "w9968cf.h"
#include "w9968cf_decoder.h"

static struct w9968cf_vpp_t* w9968cf_vpp;
static DECLARE_WAIT_QUEUE_HEAD(w9968cf_vppmod_wait);

static LIST_HEAD(w9968cf_dev_list); /* head of V4L registered cameras list */
static DEFINE_MUTEX(w9968cf_devlist_mutex); /* semaphore for list traversal */

static DECLARE_RWSEM(w9968cf_disconnect); /* prevent races with open() */


/****************************************************************************
 * Module macros and parameters                                             *
 ****************************************************************************/

MODULE_DEVICE_TABLE(usb, winbond_id_table);

MODULE_AUTHOR(W9968CF_MODULE_AUTHOR" "W9968CF_AUTHOR_EMAIL);
MODULE_DESCRIPTION(W9968CF_MODULE_NAME);
MODULE_VERSION(W9968CF_MODULE_VERSION);
MODULE_LICENSE(W9968CF_MODULE_LICENSE);
MODULE_SUPPORTED_DEVICE("Video");

static int ovmod_load = W9968CF_OVMOD_LOAD;
static unsigned short simcams = W9968CF_SIMCAMS;
static short video_nr[]={[0 ... W9968CF_MAX_DEVICES-1] = -1}; /*-1=first free*/
static unsigned int packet_size[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				     W9968CF_PACKET_SIZE};
static unsigned short max_buffers[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				       W9968CF_BUFFERS};
static int double_buffer[] = {[0 ... W9968CF_MAX_DEVICES-1] =
			      W9968CF_DOUBLE_BUFFER};
static int clamping[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_CLAMPING};
static unsigned short filter_type[]= {[0 ... W9968CF_MAX_DEVICES-1] =
				      W9968CF_FILTER_TYPE};
static int largeview[]= {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_LARGEVIEW};
static unsigned short decompression[] = {[0 ... W9968CF_MAX_DEVICES-1] =
					 W9968CF_DECOMPRESSION};
static int upscaling[]= {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_UPSCALING};
static unsigned short force_palette[] = {[0 ... W9968CF_MAX_DEVICES-1] = 0};
static int force_rgb[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_FORCE_RGB};
static int autobright[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_AUTOBRIGHT};
static int autoexp[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_AUTOEXP};
static unsigned short lightfreq[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				     W9968CF_LIGHTFREQ};
static int bandingfilter[] = {[0 ... W9968CF_MAX_DEVICES-1]=
			      W9968CF_BANDINGFILTER};
static short clockdiv[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_CLOCKDIV};
static int backlight[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_BACKLIGHT};
static int mirror[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_MIRROR};
static int monochrome[] = {[0 ... W9968CF_MAX_DEVICES-1]=W9968CF_MONOCHROME};
static unsigned int brightness[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				    W9968CF_BRIGHTNESS};
static unsigned int hue[] = {[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_HUE};
static unsigned int colour[]={[0 ... W9968CF_MAX_DEVICES-1] = W9968CF_COLOUR};
static unsigned int contrast[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				  W9968CF_CONTRAST};
static unsigned int whiteness[] = {[0 ... W9968CF_MAX_DEVICES-1] =
				   W9968CF_WHITENESS};
#ifdef W9968CF_DEBUG
static unsigned short debug = W9968CF_DEBUG_LEVEL;
static int specific_debug = W9968CF_SPECIFIC_DEBUG;
#endif

static unsigned int param_nv[24]; /* number of values per parameter */

#ifdef CONFIG_MODULES
module_param(ovmod_load, bool, 0644);
#endif
module_param(simcams, ushort, 0644);
module_param_array(video_nr, short, &param_nv[0], 0444);
module_param_array(packet_size, uint, &param_nv[1], 0444);
module_param_array(max_buffers, ushort, &param_nv[2], 0444);
module_param_array(double_buffer, bool, &param_nv[3], 0444);
module_param_array(clamping, bool, &param_nv[4], 0444);
module_param_array(filter_type, ushort, &param_nv[5], 0444);
module_param_array(largeview, bool, &param_nv[6], 0444);
module_param_array(decompression, ushort, &param_nv[7], 0444);
module_param_array(upscaling, bool, &param_nv[8], 0444);
module_param_array(force_palette, ushort, &param_nv[9], 0444);
module_param_array(force_rgb, ushort, &param_nv[10], 0444);
module_param_array(autobright, bool, &param_nv[11], 0444);
module_param_array(autoexp, bool, &param_nv[12], 0444);
module_param_array(lightfreq, ushort, &param_nv[13], 0444);
module_param_array(bandingfilter, bool, &param_nv[14], 0444);
module_param_array(clockdiv, short, &param_nv[15], 0444);
module_param_array(backlight, bool, &param_nv[16], 0444);
module_param_array(mirror, bool, &param_nv[17], 0444);
module_param_array(monochrome, bool, &param_nv[18], 0444);
module_param_array(brightness, uint, &param_nv[19], 0444);
module_param_array(hue, uint, &param_nv[20], 0444);
module_param_array(colour, uint, &param_nv[21], 0444);
module_param_array(contrast, uint, &param_nv[22], 0444);
module_param_array(whiteness, uint, &param_nv[23], 0444);
#ifdef W9968CF_DEBUG
module_param(debug, ushort, 0644);
module_param(specific_debug, bool, 0644);
#endif

#ifdef CONFIG_MODULES
MODULE_PARM_DESC(ovmod_load,
		 "\n<0|1> Automatic 'ovcamchip' module loading."
		 "\n0 disabled, 1 enabled."
		 "\nIf enabled,'insmod' searches for the required 'ovcamchip'"
		 "\nmodule in the system, according to its configuration, and"
		 "\nattempts to load that module automatically. This action is"
		 "\nperformed once as soon as the 'w9968cf' module is loaded"
		 "\ninto memory."
		 "\nDefault value is "__MODULE_STRING(W9968CF_OVMOD_LOAD)"."
		 "\n");
#endif
MODULE_PARM_DESC(simcams,
		 "\n<n> Number of cameras allowed to stream simultaneously."
		 "\nn may vary from 0 to "
		 __MODULE_STRING(W9968CF_MAX_DEVICES)"."
		 "\nDefault value is "__MODULE_STRING(W9968CF_SIMCAMS)"."
		 "\n");
MODULE_PARM_DESC(video_nr,
		 "\n<-1|n[,...]> Specify V4L minor mode number."
		 "\n -1 = use next available (default)"
		 "\n  n = use minor number n (integer >= 0)"
		 "\nYou can specify up to "__MODULE_STRING(W9968CF_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");
MODULE_PARM_DESC(packet_size,
		 "\n<n[,...]> Specify the maximum data payload"
		 "\nsize in bytes for alternate settings, for each device."
		 "\nn is scaled between 63 and 1023 "
		 "(default is "__MODULE_STRING(W9968CF_PACKET_SIZE)")."
		 "\n");
MODULE_PARM_DESC(max_buffers,
		 "\n<n[,...]> For advanced users."
		 "\nSpecify the maximum number of video frame buffers"
		 "\nto allocate for each device, from 2 to "
		 __MODULE_STRING(W9968CF_MAX_BUFFERS)
		 ". (default is "__MODULE_STRING(W9968CF_BUFFERS)")."
		 "\n");
MODULE_PARM_DESC(double_buffer,
		 "\n<0|1[,...]> "
		 "Hardware double buffering: 0 disabled, 1 enabled."
		 "\nIt should be enabled if you want smooth video output: if"
		 "\nyou obtain out of sync. video, disable it, or try to"
		 "\ndecrease the 'clockdiv' module parameter value."
		 "\nDefault value is "__MODULE_STRING(W9968CF_DOUBLE_BUFFER)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(clamping,
		 "\n<0|1[,...]> Video data clamping: 0 disabled, 1 enabled."
		 "\nDefault value is "__MODULE_STRING(W9968CF_CLAMPING)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(filter_type,
		 "\n<0|1|2[,...]> Video filter type."
		 "\n0 none, 1 (1-2-1) 3-tap filter, "
		 "2 (2-3-6-3-2) 5-tap filter."
		 "\nDefault value is "__MODULE_STRING(W9968CF_FILTER_TYPE)
		 " for every device."
		 "\nThe filter is used to reduce noise and aliasing artifacts"
		 "\nproduced by the CCD or CMOS image sensor, and the scaling"
		 " process."
		 "\n");
MODULE_PARM_DESC(largeview,
		 "\n<0|1[,...]> Large view: 0 disabled, 1 enabled."
		 "\nDefault value is "__MODULE_STRING(W9968CF_LARGEVIEW)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(upscaling,
		 "\n<0|1[,...]> Software scaling (for non-compressed video):"
		 "\n0 disabled, 1 enabled."
		 "\nDisable it if you have a slow CPU or you don't have"
		 " enough memory."
		 "\nDefault value is "__MODULE_STRING(W9968CF_UPSCALING)
		 " for every device."
		 "\nIf 'w9968cf-vpp' is not present, this parameter is"
		 " set to 0."
		 "\n");
MODULE_PARM_DESC(decompression,
		 "\n<0|1|2[,...]> Software video decompression:"
		 "\n- 0 disables decompression (doesn't allow formats needing"
		 " decompression)"
		 "\n- 1 forces decompression (allows formats needing"
		 " decompression only);"
		 "\n- 2 allows any permitted formats."
		 "\nFormats supporting compressed video are YUV422P and"
		 " YUV420P/YUV420 "
		 "\nin any resolutions where both width and height are "
		 "a multiple of 16."
		 "\nDefault value is "__MODULE_STRING(W9968CF_DECOMPRESSION)
		 " for every device."
		 "\nIf 'w9968cf-vpp' is not present, forcing decompression is "
		 "\nnot allowed; in this case this parameter is set to 2."
		 "\n");
MODULE_PARM_DESC(force_palette,
		 "\n<0"
		 "|" __MODULE_STRING(VIDEO_PALETTE_UYVY)
		 "|" __MODULE_STRING(VIDEO_PALETTE_YUV420)
		 "|" __MODULE_STRING(VIDEO_PALETTE_YUV422P)
		 "|" __MODULE_STRING(VIDEO_PALETTE_YUV420P)
		 "|" __MODULE_STRING(VIDEO_PALETTE_YUYV)
		 "|" __MODULE_STRING(VIDEO_PALETTE_YUV422)
		 "|" __MODULE_STRING(VIDEO_PALETTE_GREY)
		 "|" __MODULE_STRING(VIDEO_PALETTE_RGB555)
		 "|" __MODULE_STRING(VIDEO_PALETTE_RGB565)
		 "|" __MODULE_STRING(VIDEO_PALETTE_RGB24)
		 "|" __MODULE_STRING(VIDEO_PALETTE_RGB32)
		 "[,...]>"
		 " Force picture palette."
		 "\nIn order:"
		 "\n- 0 allows any of the following formats:"
		 "\n- UYVY    16 bpp - Original video, compression disabled"
		 "\n- YUV420  12 bpp - Original video, compression enabled"
		 "\n- YUV422P 16 bpp - Original video, compression enabled"
		 "\n- YUV420P 12 bpp - Original video, compression enabled"
		 "\n- YUVY    16 bpp - Software conversion from UYVY"
		 "\n- YUV422  16 bpp - Software conversion from UYVY"
		 "\n- GREY     8 bpp - Software conversion from UYVY"
		 "\n- RGB555  16 bpp - Software conversion from UYVY"
		 "\n- RGB565  16 bpp - Software conversion from UYVY"
		 "\n- RGB24   24 bpp - Software conversion from UYVY"
		 "\n- RGB32   32 bpp - Software conversion from UYVY"
		 "\nWhen not 0, this parameter will override 'decompression'."
		 "\nDefault value is 0 for every device."
		 "\nInitial palette is "
		 __MODULE_STRING(W9968CF_PALETTE_DECOMP_ON)"."
		 "\nIf 'w9968cf-vpp' is not present, this parameter is"
		 " set to 9 (UYVY)."
		 "\n");
MODULE_PARM_DESC(force_rgb,
		 "\n<0|1[,...]> Read RGB video data instead of BGR:"
		 "\n 1 = use RGB component ordering."
		 "\n 0 = use BGR component ordering."
		 "\nThis parameter has effect when using RGBX palettes only."
		 "\nDefault value is "__MODULE_STRING(W9968CF_FORCE_RGB)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(autobright,
		 "\n<0|1[,...]> Image sensor automatically changes brightness:"
		 "\n 0 = no, 1 = yes"
		 "\nDefault value is "__MODULE_STRING(W9968CF_AUTOBRIGHT)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(autoexp,
		 "\n<0|1[,...]> Image sensor automatically changes exposure:"
		 "\n 0 = no, 1 = yes"
		 "\nDefault value is "__MODULE_STRING(W9968CF_AUTOEXP)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(lightfreq,
		 "\n<50|60[,...]> Light frequency in Hz:"
		 "\n 50 for European and Asian lighting,"
		 " 60 for American lighting."
		 "\nDefault value is "__MODULE_STRING(W9968CF_LIGHTFREQ)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(bandingfilter,
		 "\n<0|1[,...]> Banding filter to reduce effects of"
		 " fluorescent lighting:"
		 "\n 0 disabled, 1 enabled."
		 "\nThis filter tries to reduce the pattern of horizontal"
		 "\nlight/dark bands caused by some (usually fluorescent)"
		 " lighting."
		 "\nDefault value is "__MODULE_STRING(W9968CF_BANDINGFILTER)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(clockdiv,
		 "\n<-1|n[,...]> "
		 "Force pixel clock divisor to a specific value (for experts):"
		 "\n  n may vary from 0 to 127."
		 "\n -1 for automatic value."
		 "\nSee also the 'double_buffer' module parameter."
		 "\nDefault value is "__MODULE_STRING(W9968CF_CLOCKDIV)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(backlight,
		 "\n<0|1[,...]> Objects are lit from behind:"
		 "\n 0 = no, 1 = yes"
		 "\nDefault value is "__MODULE_STRING(W9968CF_BACKLIGHT)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(mirror,
		 "\n<0|1[,...]> Reverse image horizontally:"
		 "\n 0 = no, 1 = yes"
		 "\nDefault value is "__MODULE_STRING(W9968CF_MIRROR)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(monochrome,
		 "\n<0|1[,...]> Use image sensor as monochrome sensor:"
		 "\n 0 = no, 1 = yes"
		 "\nNot all the sensors support monochrome color."
		 "\nDefault value is "__MODULE_STRING(W9968CF_MONOCHROME)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(brightness,
		 "\n<n[,...]> Set picture brightness (0-65535)."
		 "\nDefault value is "__MODULE_STRING(W9968CF_BRIGHTNESS)
		 " for every device."
		 "\nThis parameter has no effect if 'autobright' is enabled."
		 "\n");
MODULE_PARM_DESC(hue,
		 "\n<n[,...]> Set picture hue (0-65535)."
		 "\nDefault value is "__MODULE_STRING(W9968CF_HUE)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(colour,
		 "\n<n[,...]> Set picture saturation (0-65535)."
		 "\nDefault value is "__MODULE_STRING(W9968CF_COLOUR)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(contrast,
		 "\n<n[,...]> Set picture contrast (0-65535)."
		 "\nDefault value is "__MODULE_STRING(W9968CF_CONTRAST)
		 " for every device."
		 "\n");
MODULE_PARM_DESC(whiteness,
		 "\n<n[,...]> Set picture whiteness (0-65535)."
		 "\nDefault value is "__MODULE_STRING(W9968CF_WHITENESS)
		 " for every device."
		 "\n");
#ifdef W9968CF_DEBUG
MODULE_PARM_DESC(debug,
		 "\n<n> Debugging information level, from 0 to 6:"
		 "\n0 = none (use carefully)"
		 "\n1 = critical errors"
		 "\n2 = significant informations"
		 "\n3 = configuration or general messages"
		 "\n4 = warnings"
		 "\n5 = called functions"
		 "\n6 = function internals"
		 "\nLevel 5 and 6 are useful for testing only, when only "
		 "one device is used."
		 "\nDefault value is "__MODULE_STRING(W9968CF_DEBUG_LEVEL)"."
		 "\n");
MODULE_PARM_DESC(specific_debug,
		 "\n<0|1> Enable or disable specific debugging messages:"
		 "\n0 = print messages concerning every level"
		 " <= 'debug' level."
		 "\n1 = print messages concerning the level"
		 " indicated by 'debug'."
		 "\nDefault value is "
		 __MODULE_STRING(W9968CF_SPECIFIC_DEBUG)"."
		 "\n");
#endif /* W9968CF_DEBUG */


/****************************************************************************
 * Some prototypes                                                          *
 ****************************************************************************/

/* Video4linux interface */
static const struct file_operations w9968cf_fops;
static int w9968cf_open(struct inode*, struct file*);
static int w9968cf_release(struct inode*, struct file*);
static int w9968cf_mmap(struct file*, struct vm_area_struct*);
static int w9968cf_ioctl(struct inode*, struct file*, unsigned, unsigned long);
static ssize_t w9968cf_read(struct file*, char __user *, size_t, loff_t*);
static int w9968cf_v4l_ioctl(struct inode*, struct file*, unsigned int,
			     void __user *);

/* USB-specific */
static int w9968cf_start_transfer(struct w9968cf_device*);
static int w9968cf_stop_transfer(struct w9968cf_device*);
static int w9968cf_write_reg(struct w9968cf_device*, u16 value, u16 index);
static int w9968cf_read_reg(struct w9968cf_device*, u16 index);
static int w9968cf_write_fsb(struct w9968cf_device*, u16* data);
static int w9968cf_write_sb(struct w9968cf_device*, u16 value);
static int w9968cf_read_sb(struct w9968cf_device*);
static int w9968cf_upload_quantizationtables(struct w9968cf_device*);
static void w9968cf_urb_complete(struct urb *urb);

/* Low-level I2C (SMBus) I/O */
static int w9968cf_smbus_start(struct w9968cf_device*);
static int w9968cf_smbus_stop(struct w9968cf_device*);
static int w9968cf_smbus_write_byte(struct w9968cf_device*, u8 v);
static int w9968cf_smbus_read_byte(struct w9968cf_device*, u8* v);
static int w9968cf_smbus_write_ack(struct w9968cf_device*);
static int w9968cf_smbus_read_ack(struct w9968cf_device*);
static int w9968cf_smbus_refresh_bus(struct w9968cf_device*);
static int w9968cf_i2c_adap_read_byte(struct w9968cf_device* cam,
				      u16 address, u8* value);
static int w9968cf_i2c_adap_read_byte_data(struct w9968cf_device*, u16 address,
					   u8 subaddress, u8* value);
static int w9968cf_i2c_adap_write_byte(struct w9968cf_device*,
				       u16 address, u8 subaddress);
static int w9968cf_i2c_adap_fastwrite_byte_data(struct w9968cf_device*,
						u16 address, u8 subaddress,
						u8 value);

/* I2C interface to kernel */
static int w9968cf_i2c_init(struct w9968cf_device*);
static int w9968cf_i2c_smbus_xfer(struct i2c_adapter*, u16 addr,
				  unsigned short flags, char read_write,
				  u8 command, int size, union i2c_smbus_data*);
static u32 w9968cf_i2c_func(struct i2c_adapter*);
static int w9968cf_i2c_attach_inform(struct i2c_client*);
static int w9968cf_i2c_detach_inform(struct i2c_client*);

/* Memory management */
static void* rvmalloc(unsigned long size);
static void rvfree(void *mem, unsigned long size);
static void w9968cf_deallocate_memory(struct w9968cf_device*);
static int  w9968cf_allocate_memory(struct w9968cf_device*);

/* High-level image sensor control functions */
static int w9968cf_sensor_set_control(struct w9968cf_device*,int cid,int val);
static int w9968cf_sensor_get_control(struct w9968cf_device*,int cid,int *val);
static int w9968cf_sensor_cmd(struct w9968cf_device*,
			      unsigned int cmd, void *arg);
static int w9968cf_sensor_init(struct w9968cf_device*);
static int w9968cf_sensor_update_settings(struct w9968cf_device*);
static int w9968cf_sensor_get_picture(struct w9968cf_device*);
static int w9968cf_sensor_update_picture(struct w9968cf_device*,
					 struct video_picture pict);

/* Other helper functions */
static void w9968cf_configure_camera(struct w9968cf_device*,struct usb_device*,
				     enum w9968cf_model_id,
				     const unsigned short dev_nr);
static void w9968cf_adjust_configuration(struct w9968cf_device*);
static int w9968cf_turn_on_led(struct w9968cf_device*);
static int w9968cf_init_chip(struct w9968cf_device*);
static inline u16 w9968cf_valid_palette(u16 palette);
static inline u16 w9968cf_valid_depth(u16 palette);
static inline u8 w9968cf_need_decompression(u16 palette);
static int w9968cf_set_picture(struct w9968cf_device*, struct video_picture);
static int w9968cf_set_window(struct w9968cf_device*, struct video_window);
static int w9968cf_postprocess_frame(struct w9968cf_device*,
				     struct w9968cf_frame_t*);
static int w9968cf_adjust_window_size(struct w9968cf_device*, u16* w, u16* h);
static void w9968cf_init_framelist(struct w9968cf_device*);
static void w9968cf_push_frame(struct w9968cf_device*, u8 f_num);
static void w9968cf_pop_frame(struct w9968cf_device*,struct w9968cf_frame_t**);
static void w9968cf_release_resources(struct w9968cf_device*);


/****************************************************************************
 * Symbolic names                                                           *
 ****************************************************************************/

/* Used to represent a list of values and their respective symbolic names */
struct w9968cf_symbolic_list {
	const int num;
	const char *name;
};

/*--------------------------------------------------------------------------
  Returns the name of the matching element in the symbolic_list array. The
  end of the list must be marked with an element that has a NULL name.
  --------------------------------------------------------------------------*/
static inline const char *
symbolic(struct w9968cf_symbolic_list list[], const int num)
{
	int i;

	for (i = 0; list[i].name != NULL; i++)
		if (list[i].num == num)
			return (list[i].name);

	return "Unknown";
}

static struct w9968cf_symbolic_list camlist[] = {
	{ W9968CF_MOD_GENERIC, "W996[87]CF JPEG USB Dual Mode Camera" },
	{ W9968CF_MOD_CLVBWGP, "Creative Labs Video Blaster WebCam Go Plus" },

	/* Other cameras (having the same descriptors as Generic W996[87]CF) */
	{ W9968CF_MOD_ADPVDMA, "Aroma Digi Pen VGA Dual Mode ADG-5000" },
	{ W9986CF_MOD_AAU, "AVerMedia AVerTV USB" },
	{ W9968CF_MOD_CLVBWG, "Creative Labs Video Blaster WebCam Go" },
	{ W9968CF_MOD_LL, "Lebon LDC-035A" },
	{ W9968CF_MOD_EEEMC, "Ezonics EZ-802 EZMega Cam" },
	{ W9968CF_MOD_OOE, "OmniVision OV8610-EDE" },
	{ W9968CF_MOD_ODPVDMPC, "OPCOM Digi Pen VGA Dual Mode Pen Camera" },
	{ W9968CF_MOD_PDPII, "Pretec Digi Pen-II" },
	{ W9968CF_MOD_PDP480, "Pretec DigiPen-480" },

	{  -1, NULL }
};

static struct w9968cf_symbolic_list senlist[] = {
	{ CC_OV76BE,   "OV76BE" },
	{ CC_OV7610,   "OV7610" },
	{ CC_OV7620,   "OV7620" },
	{ CC_OV7620AE, "OV7620AE" },
	{ CC_OV6620,   "OV6620" },
	{ CC_OV6630,   "OV6630" },
	{ CC_OV6630AE, "OV6630AE" },
	{ CC_OV6630AF, "OV6630AF" },
	{ -1, NULL }
};

/* Video4Linux1 palettes */
static struct w9968cf_symbolic_list v4l1_plist[] = {
	{ VIDEO_PALETTE_GREY,    "GREY" },
	{ VIDEO_PALETTE_HI240,   "HI240" },
	{ VIDEO_PALETTE_RGB565,  "RGB565" },
	{ VIDEO_PALETTE_RGB24,   "RGB24" },
	{ VIDEO_PALETTE_RGB32,   "RGB32" },
	{ VIDEO_PALETTE_RGB555,  "RGB555" },
	{ VIDEO_PALETTE_YUV422,  "YUV422" },
	{ VIDEO_PALETTE_YUYV,    "YUYV" },
	{ VIDEO_PALETTE_UYVY,    "UYVY" },
	{ VIDEO_PALETTE_YUV420,  "YUV420" },
	{ VIDEO_PALETTE_YUV411,  "YUV411" },
	{ VIDEO_PALETTE_RAW,     "RAW" },
	{ VIDEO_PALETTE_YUV422P, "YUV422P" },
	{ VIDEO_PALETTE_YUV411P, "YUV411P" },
	{ VIDEO_PALETTE_YUV420P, "YUV420P" },
	{ VIDEO_PALETTE_YUV410P, "YUV410P" },
	{ -1, NULL }
};

/* Decoder error codes: */
static struct w9968cf_symbolic_list decoder_errlist[] = {
	{ W9968CF_DEC_ERR_CORRUPTED_DATA, "Corrupted data" },
	{ W9968CF_DEC_ERR_BUF_OVERFLOW,   "Buffer overflow" },
	{ W9968CF_DEC_ERR_NO_SOI,         "SOI marker not found" },
	{ W9968CF_DEC_ERR_NO_SOF0,        "SOF0 marker not found" },
	{ W9968CF_DEC_ERR_NO_SOS,         "SOS marker not found" },
	{ W9968CF_DEC_ERR_NO_EOI,         "EOI marker not found" },
	{ -1, NULL }
};

/* URB error codes: */
static struct w9968cf_symbolic_list urb_errlist[] = {
	{ -ENOMEM,    "No memory for allocation of internal structures" },
	{ -ENOSPC,    "The host controller's bandwidth is already consumed" },
	{ -ENOENT,    "URB was canceled by unlink_urb" },
	{ -EXDEV,     "ISO transfer only partially completed" },
	{ -EAGAIN,    "Too match scheduled for the future" },
	{ -ENXIO,     "URB already queued" },
	{ -EFBIG,     "Too much ISO frames requested" },
	{ -ENOSR,     "Buffer error (overrun)" },
	{ -EPIPE,     "Specified endpoint is stalled (device not responding)"},
	{ -EOVERFLOW, "Babble (too much data)" },
	{ -EPROTO,    "Bit-stuff error (bad cable?)" },
	{ -EILSEQ,    "CRC/Timeout" },
	{ -ETIME,     "Device does not respond to token" },
	{ -ETIMEDOUT, "Device does not respond to command" },
	{ -1, NULL }
};

/****************************************************************************
 * Memory management functions                                              *
 ****************************************************************************/
static void* rvmalloc(unsigned long size)
{
	void* mem;
	unsigned long adr;

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

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

	return mem;
}


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

	if (!mem)
		return;

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


/*--------------------------------------------------------------------------
  Deallocate previously allocated memory.
  --------------------------------------------------------------------------*/
static void w9968cf_deallocate_memory(struct w9968cf_device* cam)
{
	u8 i;

	/* Free the isochronous transfer buffers */
	for (i = 0; i < W9968CF_URBS; i++) {
		kfree(cam->transfer_buffer[i]);
		cam->transfer_buffer[i] = NULL;
	}

	/* Free temporary frame buffer */
	if (cam->frame_tmp.buffer) {
		rvfree(cam->frame_tmp.buffer, cam->frame_tmp.size);
		cam->frame_tmp.buffer = NULL;
	}

	/* Free helper buffer */
	if (cam->frame_vpp.buffer) {
		rvfree(cam->frame_vpp.buffer, cam->frame_vpp.size);
		cam->frame_vpp.buffer = NULL;
	}

	/* Free video frame buffers */
	if (cam->frame[0].buffer) {
		rvfree(cam->frame[0].buffer, cam->nbuffers*cam->frame[0].size);
		cam->frame[0].buffer = NULL;
	}

	cam->nbuffers = 0;

	DBG(5, "Memory successfully deallocated")
}


/*--------------------------------------------------------------------------
  Allocate memory buffers for USB transfers and video frames.
  This function is called by open() only.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_allocate_memory(struct w9968cf_device* cam)
{
	const u16 p_size = wMaxPacketSize[cam->altsetting-1];
	void* buff = NULL;
	unsigned long hw_bufsize, vpp_bufsize;
	u8 i, bpp;

	/* NOTE: Deallocation is done elsewhere in case of error */

	/* Calculate the max amount of raw data per frame from the device */
	hw_bufsize = cam->maxwidth*cam->maxheight*2;

	/* Calculate the max buf. size needed for post-processing routines */
	bpp = (w9968cf_vpp) ? 4 : 2;
	if (cam->upscaling)
		vpp_bufsize = max(W9968CF_MAX_WIDTH*W9968CF_MAX_HEIGHT*bpp,
				  cam->maxwidth*cam->maxheight*bpp);
	else
		vpp_bufsize = cam->maxwidth*cam->maxheight*bpp;

	/* Allocate memory for the isochronous transfer buffers */
	for (i = 0; i < W9968CF_URBS; i++) {
		if (!(cam->transfer_buffer[i] =
		      kzalloc(W9968CF_ISO_PACKETS*p_size, GFP_KERNEL))) {
			DBG(1, "Couldn't allocate memory for the isochronous "
			       "transfer buffers (%u bytes)",
			    p_size * W9968CF_ISO_PACKETS)
			return -ENOMEM;
		}
	}

	/* Allocate memory for the temporary frame buffer */
	if (!(cam->frame_tmp.buffer = rvmalloc(hw_bufsize))) {
		DBG(1, "Couldn't allocate memory for the temporary "
		       "video frame buffer (%lu bytes)", hw_bufsize)
		return -ENOMEM;
	}
	cam->frame_tmp.size = hw_bufsize;
	cam->frame_tmp.number = -1;

	/* Allocate memory for the helper buffer */
	if (w9968cf_vpp) {
		if (!(cam->frame_vpp.buffer = rvmalloc(vpp_bufsize))) {
			DBG(1, "Couldn't allocate memory for the helper buffer"
			       " (%lu bytes)", vpp_bufsize)
			return -ENOMEM;
		}
		cam->frame_vpp.size = vpp_bufsize;
	} else
		cam->frame_vpp.buffer = NULL;

	/* Allocate memory for video frame buffers */
	cam->nbuffers = cam->max_buffers;
	while (cam->nbuffers >= 2) {
		if ((buff = rvmalloc(cam->nbuffers * vpp_bufsize)))
			break;
		else
			cam->nbuffers--;
	}

	if (!buff) {
		DBG(1, "Couldn't allocate memory for the video frame buffers")
		cam->nbuffers = 0;
		return -ENOMEM;
	}

	if (cam->nbuffers != cam->max_buffers)
		DBG(2, "Couldn't allocate memory for %u video frame buffers. "
		       "Only memory for %u buffers has been allocated",
		    cam->max_buffers, cam->nbuffers)

	for (i = 0; i < cam->nbuffers; i++) {
		cam->frame[i].buffer = buff + i*vpp_bufsize;
		cam->frame[i].size = vpp_bufsize;
		cam->frame[i].number = i;
		/* Circular list */
		if (i != cam->nbuffers-1)
			cam->frame[i].next = &cam->frame[i+1];
		else
			cam->frame[i].next = &cam->frame[0];
		cam->frame[i].status = F_UNUSED;
	}

	DBG(5, "Memory successfully allocated")
	return 0;
}


/****************************************************************************
 * USB-specific functions                                                   *
 ****************************************************************************/

/*--------------------------------------------------------------------------
  This is an handler function which is called after the URBs are completed.
  It collects multiple data packets coming from the camera by putting them
  into frame buffers: one or more zero data length data packets are used to
  mark the end of a video frame; the first non-zero data packet is the start
  of the next video frame; if an error is encountered in a packet, the entire
  video frame is discarded and grabbed again.
  If there are no requested frames in the FIFO list, packets are collected into
  a temporary buffer.
  --------------------------------------------------------------------------*/
static void w9968cf_urb_complete(struct urb *urb)
{
	struct w9968cf_device* cam = (struct w9968cf_device*)urb->context;
	struct w9968cf_frame_t** f;
	unsigned int len, status;
	void* pos;
	u8 i;
	int err = 0;

	if ((!cam->streaming) || cam->disconnected) {
		DBG(4, "Got interrupt, but not streaming")
		return;
	}

	/* "(*f)" will be used instead of "cam->frame_current" */
	f = &cam->frame_current;

	/* If a frame has been requested and we are grabbing into
	   the temporary frame, we'll switch to that requested frame */
	if ((*f) == &cam->frame_tmp && *cam->requested_frame) {
		if (cam->frame_tmp.status == F_GRABBING) {
			w9968cf_pop_frame(cam, &cam->frame_current);
			(*f)->status = F_GRABBING;
			(*f)->length = cam->frame_tmp.length;
			memcpy((*f)->buffer, cam->frame_tmp.buffer,
			       (*f)->length);
			DBG(6, "Switched from temp. frame to frame #%d",
			    (*f)->number)
		}
	}

	for (i = 0; i < urb->number_of_packets; i++) {
		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 && len != 0) {
			DBG(4, "URB failed, error in data packet "
			       "(error #%u, %s)",
			    status, symbolic(urb_errlist, status))
			(*f)->status = F_ERROR;
			continue;
		}

		if (len) { /* start of frame */

			if ((*f)->status == F_UNUSED) {
				(*f)->status = F_GRABBING;
				(*f)->length = 0;
			}

			/* Buffer overflows shouldn't happen, however...*/
			if ((*f)->length + len > (*f)->size) {
				DBG(4, "Buffer overflow: bad data packets")
				(*f)->status = F_ERROR;
			}

			if ((*f)->status == F_GRABBING) {
				memcpy((*f)->buffer + (*f)->length, pos, len);
				(*f)->length += len;
			}

		} else if ((*f)->status == F_GRABBING) { /* end of frame */

			DBG(6, "Frame #%d successfully grabbed", (*f)->number)

			if (cam->vpp_flag & VPP_DECOMPRESSION) {
				err = w9968cf_vpp->check_headers((*f)->buffer,
								 (*f)->length);
				if (err) {
					DBG(4, "Skip corrupted frame: %s",
					    symbolic(decoder_errlist, err))
					(*f)->status = F_UNUSED;
					continue; /* grab this frame again */
				}
			}

			(*f)->status = F_READY;
			(*f)->queued = 0;

			/* Take a pointer to the new frame from the FIFO list.
			   If the list is empty,we'll use the temporary frame*/
			if (*cam->requested_frame)
				w9968cf_pop_frame(cam, &cam->frame_current);
			else {
				cam->frame_current = &cam->frame_tmp;
				(*f)->status = F_UNUSED;
			}

		} else if ((*f)->status == F_ERROR)
			(*f)->status = F_UNUSED; /* grab it again */

		PDBGG("Frame length %lu | pack.#%u | pack.len. %u | state %d",
		      (unsigned long)(*f)->length, i, len, (*f)->status)

	} /* end for */

	/* Resubmit this URB */
	urb->dev = cam->usbdev;
	urb->status = 0;
	spin_lock(&cam->urb_lock);
	if (cam->streaming)
		if ((err = usb_submit_urb(urb, GFP_ATOMIC))) {
			cam->misconfigured = 1;
			DBG(1, "Couldn't resubmit the URB: error %d, %s",
			    err, symbolic(urb_errlist, err))
		}
	spin_unlock(&cam->urb_lock);

	/* Wake up the user process */
	wake_up_interruptible(&cam->wait_queue);
}


/*---------------------------------------------------------------------------
  Setup the URB structures for the isochronous transfer.
  Submit the URBs so that the data transfer begins.
  Return 0 on success, a negative number otherwise.
  ---------------------------------------------------------------------------*/
static int w9968cf_start_transfer(struct w9968cf_device* cam)
{
	struct usb_device *udev = cam->usbdev;
	struct urb* urb;
	const u16 p_size = wMaxPacketSize[cam->altsetting-1];
	u16 w, h, d;
	int vidcapt;
	u32 t_size;
	int err = 0;
	s8 i, j;

	for (i = 0; i < W9968CF_URBS; i++) {
		urb = usb_alloc_urb(W9968CF_ISO_PACKETS, GFP_KERNEL);
		if (!urb) {
			for (j = 0; j < i; j++)
				usb_free_urb(cam->urb[j]);
			DBG(1, "Couldn't allocate the URB structures")
			return -ENOMEM;
		}

		cam->urb[i] = urb;
		urb->dev = udev;
		urb->context = (void*)cam;
		urb->pipe = usb_rcvisocpipe(udev, 1);
		urb->transfer_flags = URB_ISO_ASAP;
		urb->number_of_packets = W9968CF_ISO_PACKETS;
		urb->complete = w9968cf_urb_complete;
		urb->transfer_buffer = cam->transfer_buffer[i];
		urb->transfer_buffer_length = p_size*W9968CF_ISO_PACKETS;
		urb->interval = 1;
		for (j = 0; j < W9968CF_ISO_PACKETS; j++) {
			urb->iso_frame_desc[j].offset = p_size*j;
			urb->iso_frame_desc[j].length = p_size;
		}
	}

	/* Transfer size per frame, in WORD ! */
	d = cam->hw_depth;
	w = cam->hw_width;
	h = cam->hw_height;

	t_size = (w*h*d)/16;

	err = w9968cf_write_reg(cam, 0xbf17, 0x00); /* reset everything */
	err += w9968cf_write_reg(cam, 0xbf10, 0x00); /* normal operation */

	/* Transfer size */
	err += w9968cf_write_reg(cam, t_size & 0xffff, 0x3d); /* low bits */
	err += w9968cf_write_reg(cam, t_size >> 16, 0x3e);    /* high bits */

	if (cam->vpp_flag & VPP_DECOMPRESSION)
		err += w9968cf_upload_quantizationtables(cam);

	vidcapt = w9968cf_read_reg(cam, 0x16); /* read picture settings */
	err += w9968cf_write_reg(cam, vidcapt|0x8000, 0x16); /* capt. enable */

	err += usb_set_interface(udev, 0, cam->altsetting);
	err += w9968cf_write_reg(cam, 0x8a05, 0x3c); /* USB FIFO enable */

	if (err || (vidcapt < 0)) {
		for (i = 0; i < W9968CF_URBS; i++)
			usb_free_urb(cam->urb[i]);
		DBG(1, "Couldn't tell the camera to start the data transfer")
		return err;
	}

	w9968cf_init_framelist(cam);

	/* Begin to grab into the temporary buffer */
	cam->frame_tmp.status = F_UNUSED;
	cam->frame_tmp.queued = 0;
	cam->frame_current = &cam->frame_tmp;

	if (!(cam->vpp_flag & VPP_DECOMPRESSION))
		DBG(5, "Isochronous transfer size: %lu bytes/frame",
		    (unsigned long)t_size*2)

	DBG(5, "Starting the isochronous transfer...")

	cam->streaming = 1;

	/* Submit the URBs */
	for (i = 0; i < W9968CF_URBS; i++) {
		err = usb_submit_urb(cam->urb[i], GFP_KERNEL);
		if (err) {
			cam->streaming = 0;
			for (j = i-1; j >= 0; j--) {
				usb_kill_urb(cam->urb[j]);
				usb_free_urb(cam->urb[j]);
			}
			DBG(1, "Couldn't send a transfer request to the "
			       "USB core (error #%d, %s)", err,
			    symbolic(urb_errlist, err))
			return err;
		}
	}

	return 0;
}


/*--------------------------------------------------------------------------
  Stop the isochronous transfer and set alternate setting to 0 (0Mb/s).
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_stop_transfer(struct w9968cf_device* cam)
{
	struct usb_device *udev = cam->usbdev;
	unsigned long lock_flags;
	int err = 0;
	s8 i;

	if (!cam->streaming)
		return 0;

	/* This avoids race conditions with usb_submit_urb()
	   in the URB completition handler */
	spin_lock_irqsave(&cam->urb_lock, lock_flags);
	cam->streaming = 0;
	spin_unlock_irqrestore(&cam->urb_lock, lock_flags);

	for (i = W9968CF_URBS-1; i >= 0; i--)
		if (cam->urb[i]) {
			usb_kill_urb(cam->urb[i]);
			usb_free_urb(cam->urb[i]);
			cam->urb[i] = NULL;
		}

	if (cam->disconnected)
		goto exit;

	err = w9968cf_write_reg(cam, 0x0a05, 0x3c); /* stop USB transfer */
	err += usb_set_interface(udev, 0, 0); /* 0 Mb/s */
	err += w9968cf_write_reg(cam, 0x0000, 0x39); /* disable JPEG encoder */
	err += w9968cf_write_reg(cam, 0x0000, 0x16); /* stop video capture */

	if (err) {
		DBG(2, "Failed to tell the camera to stop the isochronous "
		       "transfer. However this is not a critical error.")
		return -EIO;
	}

exit:
	DBG(5, "Isochronous transfer stopped")
	return 0;
}


/*--------------------------------------------------------------------------
  Write a W9968CF register.
  Return 0 on success, -1 otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_write_reg(struct w9968cf_device* cam, u16 value, u16 index)
{
	struct usb_device* udev = cam->usbdev;
	int res;

	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
			      value, index, NULL, 0, W9968CF_USB_CTRL_TIMEOUT);

	if (res < 0)
		DBG(4, "Failed to write a register "
		       "(value 0x%04X, index 0x%02X, error #%d, %s)",
		    value, index, res, symbolic(urb_errlist, res))

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


/*--------------------------------------------------------------------------
  Read a W9968CF register.
  Return the register value on success, -1 otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_read_reg(struct w9968cf_device* cam, u16 index)
{
	struct usb_device* udev = cam->usbdev;
	u16* buff = cam->control_buffer;
	int res;

	res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 1,
			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      0, index, buff, 2, W9968CF_USB_CTRL_TIMEOUT);

	if (res < 0)
		DBG(4, "Failed to read a register "
		       "(index 0x%02X, error #%d, %s)",
		    index, res, symbolic(urb_errlist, res))

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


/*--------------------------------------------------------------------------
  Write 64-bit data to the fast serial bus registers.
  Return 0 on success, -1 otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_write_fsb(struct w9968cf_device* cam, u16* data)
{
	struct usb_device* udev = cam->usbdev;
	u16 value;
	int res;

	value = *data++;

	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
			      value, 0x06, data, 6, W9968CF_USB_CTRL_TIMEOUT);

	if (res < 0)
		DBG(4, "Failed to write the FSB registers "
		       "(error #%d, %s)", res, symbolic(urb_errlist, res))

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


/*--------------------------------------------------------------------------
  Write data to the serial bus control register.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_write_sb(struct w9968cf_device* cam, u16 value)
{
	int err = 0;

	err = w9968cf_write_reg(cam, value, 0x01);
	udelay(W9968CF_I2C_BUS_DELAY);

	return err;
}


/*--------------------------------------------------------------------------
  Read data from the serial bus control register.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_read_sb(struct w9968cf_device* cam)
{
	int v = 0;

	v = w9968cf_read_reg(cam, 0x01);
	udelay(W9968CF_I2C_BUS_DELAY);

	return v;
}


/*--------------------------------------------------------------------------
  Upload quantization tables for the JPEG compression.
  This function is called by w9968cf_start_transfer().
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_upload_quantizationtables(struct w9968cf_device* cam)
{
	u16 a, b;
	int err = 0, i, j;

	err += w9968cf_write_reg(cam, 0x0010, 0x39); /* JPEG clock enable */

	for (i = 0, j = 0; i < 32; i++, j += 2) {
		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j+1]) << 8);
		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j+1]) << 8);
		err += w9968cf_write_reg(cam, a, 0x40+i);
		err += w9968cf_write_reg(cam, b, 0x60+i);
	}
	err += w9968cf_write_reg(cam, 0x0012, 0x39); /* JPEG encoder enable */

	return err;
}


/****************************************************************************
 * Low-level I2C I/O functions.                                             *
 * The adapter supports the following I2C transfer functions:               *
 * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
 * i2c_adap_read_byte_data()                                                *
 * i2c_adap_read_byte()                                                     *
 ****************************************************************************/

static int w9968cf_smbus_start(struct w9968cf_device* cam)
{
	int err = 0;

	err += w9968cf_write_sb(cam, 0x0011); /* SDE=1, SDA=0, SCL=1 */
	err += w9968cf_write_sb(cam, 0x0010); /* SDE=1, SDA=0, SCL=0 */

	return err;
}


static int w9968cf_smbus_stop(struct w9968cf_device* cam)
{
	int err = 0;

	err += w9968cf_write_sb(cam, 0x0011); /* SDE=1, SDA=0, SCL=1 */
	err += w9968cf_write_sb(cam, 0x0013); /* SDE=1, SDA=1, SCL=1 */

	return err;
}


static int w9968cf_smbus_write_byte(struct w9968cf_device* cam, u8 v)
{
	u8 bit;
	int err = 0, sda;

	for (bit = 0 ; bit < 8 ; bit++) {
		sda = (v & 0x80) ? 2 : 0;
		v <<= 1;
		/* SDE=1, SDA=sda, SCL=0 */
		err += w9968cf_write_sb(cam, 0x10 | sda);
		/* SDE=1, SDA=sda, SCL=1 */
		err += w9968cf_write_sb(cam, 0x11 | sda);
		/* SDE=1, SDA=sda, SCL=0 */
		err += w9968cf_write_sb(cam, 0x10 | sda);
	}

	return err;
}


static int w9968cf_smbus_read_byte(struct w9968cf_device* cam, u8* v)
{
	u8 bit;
	int err = 0;

	*v = 0;
	for (bit = 0 ; bit < 8 ; bit++) {
		*v <<= 1;
		err += w9968cf_write_sb(cam, 0x0013);
		*v |= (w9968cf_read_sb(cam) & 0x0008) ? 1 : 0;
		err += w9968cf_write_sb(cam, 0x0012);
	}

	return err;
}


static int w9968cf_smbus_write_ack(struct w9968cf_device* cam)
{
	int err = 0;

	err += w9968cf_write_sb(cam, 0x0010); /* SDE=1, SDA=0, SCL=0 */
	err += w9968cf_write_sb(cam, 0x0011); /* SDE=1, SDA=0, SCL=1 */
	err += w9968cf_write_sb(cam, 0x0010); /* SDE=1, SDA=0, SCL=0 */

	return err;
}


static int w9968cf_smbus_read_ack(struct w9968cf_device* cam)
{
	int err = 0, sda;

	err += w9968cf_write_sb(cam, 0x0013); /* SDE=1, SDA=1, SCL=1 */
	sda = (w9968cf_read_sb(cam) & 0x08) ? 1 : 0; /* sda = SDA */
	err += w9968cf_write_sb(cam, 0x0012); /* SDE=1, SDA=1, SCL=0 */
	if (sda < 0)
		err += sda;
	if (sda == 1) {
		DBG(6, "Couldn't receive the ACK")
		err += -1;
	}

	return err;
}


/* This seems to refresh the communication through the serial bus */
static int w9968cf_smbus_refresh_bus(struct w9968cf_device* cam)
{
	int err = 0, j;

	for (j = 1; j <= 10; j++) {
		err = w9968cf_write_reg(cam, 0x0020, 0x01);
		err += w9968cf_write_reg(cam, 0x0000, 0x01);
		if (err)
			break;
	}

	return err;
}


/* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
static int
w9968cf_i2c_adap_fastwrite_byte_data(struct w9968cf_device* cam,
				     u16 address, u8 subaddress,u8 value)
{
	u16* data = cam->data_buffer;
	int err = 0;

	err += w9968cf_smbus_refresh_bus(cam);

	/* Enable SBUS outputs */
	err += w9968cf_write_sb(cam, 0x0020);

	data[0] = 0x082f | ((address & 0x80) ? 0x1500 : 0x0);
	data[0] |= (address & 0x40) ? 0x4000 : 0x0;
	data[1] = 0x2082 | ((address & 0x40) ? 0x0005 : 0x0);
	data[1] |= (address & 0x20) ? 0x0150 : 0x0;
	data[1] |= (address & 0x10) ? 0x5400 : 0x0;
	data[2] = 0x8208 | ((address & 0x08) ? 0x0015 : 0x0);
	data[2] |= (address & 0x04) ? 0x0540 : 0x0;
	data[2] |= (address & 0x02) ? 0x5000 : 0x0;
	data[3] = 0x1d20 | ((address & 0x02) ? 0x0001 : 0x0);
	data[3] |= (address & 0x01) ? 0x0054 : 0x0;

	err += w9968cf_write_fsb(cam, data);

	data[0] = 0x8208 | ((subaddress & 0x80) ? 0x0015 : 0x0);
	data[0] |= (subaddress & 0x40) ? 0x0540 : 0x0;
	data[0] |= (subaddress & 0x20) ? 0x5000 : 0x0;
	data[1] = 0x0820 | ((subaddress & 0x20) ? 0x0001 : 0x0);
	data[1] |= (subaddress & 0x10) ? 0x0054 : 0x0;
	data[1] |= (subaddress & 0x08) ? 0x1500 : 0x0;
	data[1] |= (subaddress & 0x04) ? 0x4000 : 0x0;
	data[2] = 0x2082 | ((subaddress & 0x04) ? 0x0005 : 0x0);
	data[2] |= (subaddress & 0x02) ? 0x0150 : 0x0;
	data[2] |= (subaddress & 0x01) ? 0x5400 : 0x0;
	data[3] = 0x001d;

	err += w9968cf_write_fsb(cam, data);

	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
	data[3] = 0xfe1d;

	err += w9968cf_write_fsb(cam, data);

	/* Disable SBUS outputs */
	err += w9968cf_write_sb(cam, 0x0000);

	if (!err)
		DBG(5, "I2C write byte data done, addr.0x%04X, subaddr.0x%02X "
		       "value 0x%02X", address, subaddress, value)
	else
		DBG(5, "I2C write byte data failed, addr.0x%04X, "
		       "subaddr.0x%02X, value 0x%02X",
		    address, subaddress, value)

	return err;
}


/* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
static int
w9968cf_i2c_adap_read_byte_data(struct w9968cf_device* cam,
				u16 address, u8 subaddress,
				u8* value)
{
	int err = 0;

	/* Serial data enable */
	err += w9968cf_write_sb(cam, 0x0013); /* don't change ! */

	err += w9968cf_smbus_start(cam);
	err += w9968cf_smbus_write_byte(cam, address);
	err += w9968cf_smbus_read_ack(cam);
	err += w9968cf_smbus_write_byte(cam, subaddress);
	err += w9968cf_smbus_read_ack(cam);
	err += w9968cf_smbus_stop(cam);
	err += w9968cf_smbus_start(cam);
	err += w9968cf_smbus_write_byte(cam, address + 1);
	err += w9968cf_smbus_read_ack(cam);
	err += w9968cf_smbus_read_byte(cam, value);
	err += w9968cf_smbus_write_ack(cam);
	err += w9968cf_smbus_stop(cam);

	/* Serial data disable */
	err += w9968cf_write_sb(cam, 0x0000);

	if (!err)
		DBG(5, "I2C read byte data done, addr.0x%04X, "
		       "subaddr.0x%02X, value 0x%02X",
		    address, subaddress, *value)
	else
		DBG(5, "I2C read byte data failed, addr.0x%04X, "
		       "subaddr.0x%02X, wrong value 0x%02X",
		    address, subaddress, *value)

	return err;
}


/* SMBus protocol: S Addr+1 Rd [A] [Value] NA P */
static int
w9968cf_i2c_adap_read_byte(struct w9968cf_device* cam,
			   u16 address, u8* value)
{
	int err = 0;

	/* Serial data enable */
	err += w9968cf_write_sb(cam, 0x0013);

	err += w9968cf_smbus_start(cam);
	err += w9968cf_smbus_write_byte(cam, address + 1);
	err += w9968cf_smbus_read_ack(cam);
	err += w9968cf_smbus_read_byte(cam, value);
	err += w9968cf_smbus_write_ack(cam);
	err += w9968cf_smbus_stop(cam);

	/* Serial data disable */
	err += w9968cf_write_sb(cam, 0x0000);

	if (!err)
		DBG(5, "I2C read byte done, addr.0x%04X, "
		       "value 0x%02X", address, *value)
	else
		DBG(5, "I2C read byte failed, addr.0x%04X, "
		       "wrong value 0x%02X", address, *value)

	return err;
}


/* SMBus protocol: S Addr Wr [A] Value [A] P */
static int
w9968cf_i2c_adap_write_byte(struct w9968cf_device* cam,
			    u16 address, u8 value)
{
	DBG(4, "i2c_write_byte() is an unsupported transfer mode")
	return -EINVAL;
}


/****************************************************************************
 * I2C interface to kernel                                                  *
 ****************************************************************************/

static int
w9968cf_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
		       unsigned short flags, char read_write, u8 command,
		       int size, union i2c_smbus_data *data)
{
	struct w9968cf_device* cam = i2c_get_adapdata(adapter);
	u8 i;
	int err = 0;

	switch (addr) {
		case OV6xx0_SID:
		case OV7xx0_SID:
			break;
		default:
			DBG(4, "Rejected slave ID 0x%04X", addr)
			return -EINVAL;
	}

	if (size == I2C_SMBUS_BYTE) {
		/* Why addr <<= 1? See OVXXX0_SID defines in ovcamchip.h */
		addr <<= 1;

		if (read_write == I2C_SMBUS_WRITE)
			err = w9968cf_i2c_adap_write_byte(cam, addr, command);
		else if (read_write == I2C_SMBUS_READ)
			err = w9968cf_i2c_adap_read_byte(cam,addr,&data->byte);

	} else if (size == I2C_SMBUS_BYTE_DATA) {
		addr <<= 1;

		if (read_write == I2C_SMBUS_WRITE)
			err = w9968cf_i2c_adap_fastwrite_byte_data(cam, addr,
							  command, data->byte);
		else if (read_write == I2C_SMBUS_READ) {
			for (i = 1; i <= W9968CF_I2C_RW_RETRIES; i++) {
				err = w9968cf_i2c_adap_read_byte_data(cam,addr,
							 command, &data->byte);
				if (err) {
					if (w9968cf_smbus_refresh_bus(cam)) {
						err = -EIO;
						break;
					}
				} else
					break;
			}

		} else
			return -EINVAL;

	} else {
		DBG(4, "Unsupported I2C transfer mode (%d)", size)
		return -EINVAL;
	}

	return err;
}


static u32 w9968cf_i2c_func(struct i2c_adapter* adap)
{
	return I2C_FUNC_SMBUS_READ_BYTE |
	       I2C_FUNC_SMBUS_READ_BYTE_DATA  |
	       I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
}


static int w9968cf_i2c_attach_inform(struct i2c_client* client)
{
	struct w9968cf_device* cam = i2c_get_adapdata(client->adapter);
	int id = client->driver->id, err = 0;

	if (id == I2C_DRIVERID_OVCAMCHIP) {
		cam->sensor_client = client;
		err = w9968cf_sensor_init(cam);
		if (err) {
			cam->sensor_client = NULL;
			return err;
		}
	} else {
		DBG(4, "Rejected client [%s] with driver [%s]",
		    client->name, client->driver->driver.name)
		return -EINVAL;
	}

	DBG(5, "I2C attach client [%s] with driver [%s]",
	    client->name, client->driver->driver.name)

	return 0;
}


static int w9968cf_i2c_detach_inform(struct i2c_client* client)
{
	struct w9968cf_device* cam = i2c_get_adapdata(client->adapter);

	if (cam->sensor_client == client)
		cam->sensor_client = NULL;

	DBG(5, "I2C detach client [%s]", client->name)

	return 0;
}


static int w9968cf_i2c_init(struct w9968cf_device* cam)
{
	int err = 0;

	static struct i2c_algorithm algo = {
		.smbus_xfer =    w9968cf_i2c_smbus_xfer,
		.functionality = w9968cf_i2c_func,
	};

	static struct i2c_adapter adap = {
		.id =                I2C_HW_SMBUS_W9968CF,
		.class =             I2C_CLASS_CAM_DIGITAL,
		.owner =             THIS_MODULE,
		.client_register =   w9968cf_i2c_attach_inform,
		.client_unregister = w9968cf_i2c_detach_inform,
		.algo =              &algo,
	};

	memcpy(&cam->i2c_adapter, &adap, sizeof(struct i2c_adapter));
	strcpy(cam->i2c_adapter.name, "w9968cf");
	cam->i2c_adapter.dev.parent = &cam->usbdev->dev;
	i2c_set_adapdata(&cam->i2c_adapter, cam);

	DBG(6, "Registering I2C adapter with kernel...")

	err = i2c_add_adapter(&cam->i2c_adapter);
	if (err)
		DBG(1, "Failed to register the I2C adapter")
	else
		DBG(5, "I2C adapter registered")

	return err;
}


/****************************************************************************
 * Helper functions                                                         *
 ****************************************************************************/

/*--------------------------------------------------------------------------
  Turn on the LED on some webcams. A beep should be heard too.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_turn_on_led(struct w9968cf_device* cam)
{
	int err = 0;

	err += w9968cf_write_reg(cam, 0xff00, 0x00); /* power-down */
	err += w9968cf_write_reg(cam, 0xbf17, 0x00); /* reset everything */
	err += w9968cf_write_reg(cam, 0xbf10, 0x00); /* normal operation */
	err += w9968cf_write_reg(cam, 0x0010, 0x01); /* serial bus, SDS high */
	err += w9968cf_write_reg(cam, 0x0000, 0x01); /* serial bus, SDS low */
	err += w9968cf_write_reg(cam, 0x0010, 0x01); /* ..high 'beep-beep' */

	if (err)
		DBG(2, "Couldn't turn on the LED")

	DBG(5, "LED turned on")

	return err;
}


/*--------------------------------------------------------------------------
  Write some registers for the device initialization.
  This function is called once on open().
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_init_chip(struct w9968cf_device* cam)
{
	unsigned long hw_bufsize = cam->maxwidth*cam->maxheight*2,
		      y0 = 0x0000,
		      u0 = y0 + hw_bufsize/2,
		      v0 = u0 + hw_bufsize/4,
		      y1 = v0 + hw_bufsize/4,
		      u1 = y1 + hw_bufsize/2,
		      v1 = u1 + hw_bufsize/4;
	int err = 0;

	err += w9968cf_write_reg(cam, 0xff00, 0x00); /* power off */
	err += w9968cf_write_reg(cam, 0xbf10, 0x00); /* power on */

	err += w9968cf_write_reg(cam, 0x405d, 0x03); /* DRAM timings */
	err += w9968cf_write_reg(cam, 0x0030, 0x04); /* SDRAM timings */

	err += w9968cf_write_reg(cam, y0 & 0xffff, 0x20); /* Y buf.0, low */
	err += w9968cf_write_reg(cam, y0 >> 16, 0x21);    /* Y buf.0, high */
	err += w9968cf_write_reg(cam, u0 & 0xffff, 0x24); /* U buf.0, low */
	err += w9968cf_write_reg(cam, u0 >> 16, 0x25);    /* U buf.0, high */
	err += w9968cf_write_reg(cam, v0 & 0xffff, 0x28); /* V buf.0, low */
	err += w9968cf_write_reg(cam, v0 >> 16, 0x29);    /* V buf.0, high */

	err += w9968cf_write_reg(cam, y1 & 0xffff, 0x22); /* Y buf.1, low */
	err += w9968cf_write_reg(cam, y1 >> 16, 0x23);    /* Y buf.1, high */
	err += w9968cf_write_reg(cam, u1 & 0xffff, 0x26); /* U buf.1, low */
	err += w9968cf_write_reg(cam, u1 >> 16, 0x27);    /* U buf.1, high */
	err += w9968cf_write_reg(cam, v1 & 0xffff, 0x2a); /* V buf.1, low */
	err += w9968cf_write_reg(cam, v1 >> 16, 0x2b);    /* V buf.1, high */

	err += w9968cf_write_reg(cam, y1 & 0xffff, 0x32); /* JPEG buf 0 low */
	err += w9968cf_write_reg(cam, y1 >> 16, 0x33);    /* JPEG buf 0 high */

	err += w9968cf_write_reg(cam, y1 & 0xffff, 0x34); /* JPEG buf 1 low */
	err += w9968cf_write_reg(cam, y1 >> 16, 0x35);    /* JPEG bug 1 high */

	err += w9968cf_write_reg(cam, 0x0000, 0x36);/* JPEG restart interval */
	err += w9968cf_write_reg(cam, 0x0804, 0x37);/*JPEG VLE FIFO threshold*/
	err += w9968cf_write_reg(cam, 0x0000, 0x38);/* disable hw up-scaling */
	err += w9968cf_write_reg(cam, 0x0000, 0x3f); /* JPEG/MCTL test data */

	err += w9968cf_set_picture(cam, cam->picture); /* this before */
	err += w9968cf_set_window(cam, cam->window);

	if (err)
		DBG(1, "Chip initialization failed")
	else
		DBG(5, "Chip successfully initialized")

	return err;
}


/*--------------------------------------------------------------------------
  Return non-zero if the palette is supported, 0 otherwise.
  --------------------------------------------------------------------------*/
static inline u16 w9968cf_valid_palette(u16 palette)
{
	u8 i = 0;
	while (w9968cf_formatlist[i].palette != 0) {
		if (palette == w9968cf_formatlist[i].palette)
			return palette;
		i++;
	}
	return 0;
}


/*--------------------------------------------------------------------------
  Return the depth corresponding to the given palette.
  Palette _must_ be supported !
  --------------------------------------------------------------------------*/
static inline u16 w9968cf_valid_depth(u16 palette)
{
	u8 i=0;
	while (w9968cf_formatlist[i].palette != palette)
		i++;

	return w9968cf_formatlist[i].depth;
}


/*--------------------------------------------------------------------------
  Return non-zero if the format requires decompression, 0 otherwise.
  --------------------------------------------------------------------------*/
static inline u8 w9968cf_need_decompression(u16 palette)
{
	u8 i = 0;
	while (w9968cf_formatlist[i].palette != 0) {
		if (palette == w9968cf_formatlist[i].palette)
			return w9968cf_formatlist[i].compression;
		i++;
	}
	return 0;
}


/*--------------------------------------------------------------------------
  Change the picture settings of the camera.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int
w9968cf_set_picture(struct w9968cf_device* cam, struct video_picture pict)
{
	u16 fmt, hw_depth, hw_palette, reg_v = 0x0000;
	int err = 0;

	/* Make sure we are using a valid depth */
	pict.depth = w9968cf_valid_depth(pict.palette);

	fmt = pict.palette;

	hw_depth = pict.depth; /* depth used by the winbond chip */
	hw_palette = pict.palette; /* palette used by the winbond chip */

	/* VS & HS polarities */
	reg_v = (cam->vs_polarity << 12) | (cam->hs_polarity << 11);

	switch (fmt)
	{
		case VIDEO_PALETTE_UYVY:
			reg_v |= 0x0000;
			cam->vpp_flag = VPP_NONE;
			break;
		case VIDEO_PALETTE_YUV422P:
			reg_v |= 0x0002;
			cam->vpp_flag = VPP_DECOMPRESSION;
			break;
		case VIDEO_PALETTE_YUV420:
		case VIDEO_PALETTE_YUV420P:
			reg_v |= 0x0003;
			cam->vpp_flag = VPP_DECOMPRESSION;
			break;
		case VIDEO_PALETTE_YUYV:
		case VIDEO_PALETTE_YUV422:
			reg_v |= 0x0000;
			cam->vpp_flag = VPP_SWAP_YUV_BYTES;
			hw_palette = VIDEO_PALETTE_UYVY;
			break;
		/* Original video is used instead of RGBX palettes.
		   Software conversion later. */
		case VIDEO_PALETTE_GREY:
		case VIDEO_PALETTE_RGB555:
		case VIDEO_PALETTE_RGB565:
		case VIDEO_PALETTE_RGB24:
		case VIDEO_PALETTE_RGB32:
			reg_v |= 0x0000; /* UYVY 16 bit is used */
			hw_depth = 16;
			hw_palette = VIDEO_PALETTE_UYVY;
			cam->vpp_flag = VPP_UYVY_TO_RGBX;
			break;
	}

	/* NOTE: due to memory issues, it is better to disable the hardware
		 double buffering during compression */
	if (cam->double_buffer && !(cam->vpp_flag & VPP_DECOMPRESSION))
		reg_v |= 0x0080;

	if (cam->clamping)
		reg_v |= 0x0020;

	if (cam->filter_type == 1)
		reg_v |= 0x0008;
	else if (cam->filter_type == 2)
		reg_v |= 0x000c;

	if ((err = w9968cf_write_reg(cam, reg_v, 0x16)))
		goto error;

	if ((err = w9968cf_sensor_update_picture(cam, pict)))
		goto error;

	/* If all went well, update the device data structure */
	memcpy(&cam->picture, &pict, sizeof(pict));
	cam->hw_depth = hw_depth;
	cam->hw_palette = hw_palette;

	/* Settings changed, so we clear the frame buffers */
	memset(cam->frame[0].buffer, 0, cam->nbuffers*cam->frame[0].size);

	DBG(4, "Palette is %s, depth is %u bpp",
	    symbolic(v4l1_plist, pict.palette), pict.depth)

	return 0;

error:
	DBG(1, "Failed to change picture settings")
	return err;
}


/*--------------------------------------------------------------------------
  Change the capture area size of the camera.
  This function _must_ be called _after_ w9968cf_set_picture().
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int
w9968cf_set_window(struct w9968cf_device* cam, struct video_window win)
{
	u16 x, y, w, h, scx, scy, cw, ch, ax, ay;
	unsigned long fw, fh;
	struct ovcamchip_window s_win;
	int err = 0;

	/* Work around to avoid FP arithmetics */
	#define SC(x) ((x) << 10)
	#define UNSC(x) ((x) >> 10)

	/* Make sure we are using a supported resolution */
	if ((err = w9968cf_adjust_window_size(cam, (u16*)&win.width,
					      (u16*)&win.height)))
		goto error;

	/* Scaling factors */
	fw = SC(win.width) / cam->maxwidth;
	fh = SC(win.height) / cam->maxheight;

	/* Set up the width and height values used by the chip */
	if ((win.width > cam->maxwidth) || (win.height > cam->maxheight)) {
		cam->vpp_flag |= VPP_UPSCALE;
		/* Calculate largest w,h mantaining the same w/h ratio */
		w = (fw >= fh) ? cam->maxwidth : SC(win.width)/fh;
		h = (fw >= fh) ? SC(win.height)/fw : cam->maxheight;
		if (w < cam->minwidth) /* just in case */
			w = cam->minwidth;
		if (h < cam->minheight) /* just in case */
			h = cam->minheight;
	} else {
		cam->vpp_flag &= ~VPP_UPSCALE;
		w = win.width;
		h = win.height;
	}

	/* x,y offsets of the cropped area */
	scx = cam->start_cropx;
	scy = cam->start_cropy;

	/* Calculate cropped area manteining the right w/h ratio */
	if (cam->largeview && !(cam->vpp_flag & VPP_UPSCALE)) {
		cw = (fw >= fh) ? cam->maxwidth : SC(win.width)/fh;
		ch = (fw >= fh) ? SC(win.height)/fw : cam->maxheight;
	} else {
		cw = w;
		ch = h;
	}

	/* Setup the window of the sensor */
	s_win.format = VIDEO_PALETTE_UYVY;
	s_win.width = cam->maxwidth;
	s_win.height = cam->maxheight;
	s_win.quarter = 0; /* full progressive video */

	/* Center it */
	s_win.x = (s_win.width - cw) / 2;
	s_win.y = (s_win.height - ch) / 2;

	/* Clock divisor */
	if (cam->clockdiv >= 0)
		s_win.clockdiv = cam->clockdiv; /* manual override */
	else
		switch (cam->sensor) {
			case CC_OV6620:
				s_win.clockdiv = 0;
				break;
			case CC_OV6630:
				s_win.clockdiv = 0;
				break;
			case CC_OV76BE:
			case CC_OV7610:
			case CC_OV7620:
				s_win.clockdiv = 0;
				break;
			default:
				s_win.clockdiv = W9968CF_DEF_CLOCKDIVISOR;
		}

	/* We have to scale win.x and win.y offsets */
	if ( (cam->largeview && !(cam->vpp_flag & VPP_UPSCALE))
	     || (cam->vpp_flag & VPP_UPSCALE) ) {
		ax = SC(win.x)/fw;
		ay = SC(win.y)/fh;
	} else {
		ax = win.x;
		ay = win.y;
	}

	if ((ax + cw) > cam->maxwidth)
		ax = cam->maxwidth - cw;

	if ((ay + ch) > cam->maxheight)
		ay = cam->maxheight - ch;

	/* Adjust win.x, win.y */
	if ( (cam->largeview && !(cam->vpp_flag & VPP_UPSCALE))
	     || (cam->vpp_flag & VPP_UPSCALE) ) {
		win.x = UNSC(ax*fw);
		win.y = UNSC(ay*fh);
	} else {
		win.x = ax;
		win.y = ay;
	}

	/* Offsets used by the chip */
	x = ax + s_win.x;
	y = ay + s_win.y;

	/* Go ! */
	if ((err = w9968cf_sensor_cmd(cam, OVCAMCHIP_CMD_S_MODE, &s_win)))
		goto error;

	err += w9968cf_write_reg(cam, scx + x, 0x10);
	err += w9968cf_write_reg(cam, scy + y, 0x11);
	err += w9968cf_write_reg(cam, scx + x + cw, 0x12);
	err += w9968cf_write_reg(cam, scy + y + ch, 0x13);
	err += w9968cf_write_reg(cam, w, 0x14);
	err += w9968cf_write_reg(cam, h, 0x15);

	/* JPEG width & height */
	err += w9968cf_write_reg(cam, w, 0x30);
	err += w9968cf_write_reg(cam, h, 0x31);

	/* Y & UV frame buffer strides (in WORD) */
	if (cam->vpp_flag & VPP_DECOMPRESSION) {
		err += w9968cf_write_reg(cam, w/2, 0x2c);
		err += w9968cf_write_reg(cam, w/4, 0x2d);
	} else
		err += w9968cf_write_reg(cam, w, 0x2c);

	if (err)
		goto error;

	/* If all went well, update the device data structure */
	memcpy(&cam->window, &win, sizeof(win));
	cam->hw_width = w;
	cam->hw_height = h;

	/* Settings changed, so we clear the frame buffers */
	memset(cam->frame[0].buffer, 0, cam->nbuffers*cam->frame[0].size);

	DBG(4, "The capture area is %dx%d, Offset (x,y)=(%u,%u)",
	    win.width, win.height, win.x, win.y)

	PDBGG("x=%u ,y=%u, w=%u, h=%u, ax=%u, ay=%u, s_win.x=%u, s_win.y=%u, "
	      "cw=%u, ch=%u, win.x=%u, win.y=%u, win.width=%u, win.height=%u",
	      x, y, w, h, ax, ay, s_win.x, s_win.y, cw, ch, win.x, win.y,
	      win.width, win.height)

	return 0;

error:
	DBG(1, "Failed to change the capture area size")
	return err;
}


/*--------------------------------------------------------------------------
  Adjust the asked values for window width and height.
  Return 0 on success, -1 otherwise.
  --------------------------------------------------------------------------*/
static int
w9968cf_adjust_window_size(struct w9968cf_device* cam, u16* width, u16* height)
{
	u16 maxw, maxh;

	if ((*width < cam->minwidth) || (*height < cam->minheight))
		return -ERANGE;

	maxw = cam->upscaling && !(cam->vpp_flag & VPP_DECOMPRESSION) &&
	       w9968cf_vpp ? max((u16)W9968CF_MAX_WIDTH, cam->maxwidth)
			   : cam->maxwidth;
	maxh = cam->upscaling && !(cam->vpp_flag & VPP_DECOMPRESSION) &&
	       w9968cf_vpp ? max((u16)W9968CF_MAX_HEIGHT, cam->maxheight)
			   : cam->maxheight;

	if (*width > maxw)
		*width = maxw;
	if (*height > maxh)
		*height = maxh;

	if (cam->vpp_flag & VPP_DECOMPRESSION) {
		*width  &= ~15L; /* multiple of 16 */
		*height &= ~15L;
	}

	PDBGG("Window size adjusted w=%u, h=%u ", *width, *height)

	return 0;
}


/*--------------------------------------------------------------------------
  Initialize the FIFO list of requested frames.
  --------------------------------------------------------------------------*/
static void w9968cf_init_framelist(struct w9968cf_device* cam)
{
	u8 i;

	for (i = 0; i < cam->nbuffers; i++) {
		cam->requested_frame[i] = NULL;
		cam->frame[i].queued = 0;
		cam->frame[i].status = F_UNUSED;
	}
}


/*--------------------------------------------------------------------------
  Add a frame in the FIFO list of requested frames.
  This function is called in process context.
  --------------------------------------------------------------------------*/
static void w9968cf_push_frame(struct w9968cf_device* cam, u8 f_num)
{
	u8 f;
	unsigned long lock_flags;

	spin_lock_irqsave(&cam->flist_lock, lock_flags);

	for (f=0; cam->requested_frame[f] != NULL; f++);
	cam->requested_frame[f] = &cam->frame[f_num];
	cam->frame[f_num].queued = 1;
	cam->frame[f_num].status = F_UNUSED; /* clear the status */

	spin_unlock_irqrestore(&cam->flist_lock, lock_flags);

	DBG(6, "Frame #%u pushed into the FIFO list. Position %u", f_num, f)
}


/*--------------------------------------------------------------------------
  Read, store and remove the first pointer in the FIFO list of requested
  frames. This function is called in interrupt context.
  --------------------------------------------------------------------------*/
static void
w9968cf_pop_frame(struct w9968cf_device* cam, struct w9968cf_frame_t** framep)
{
	u8 i;

	spin_lock(&cam->flist_lock);

	*framep = cam->requested_frame[0];

	/* Shift the list of pointers */
	for (i = 0; i < cam->nbuffers-1; i++)
		cam->requested_frame[i] = cam->requested_frame[i+1];
	cam->requested_frame[i] = NULL;

	spin_unlock(&cam->flist_lock);

	DBG(6,"Popped frame #%d from the list", (*framep)->number)
}


/*--------------------------------------------------------------------------
  High-level video post-processing routine on grabbed frames.
  Return 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int
w9968cf_postprocess_frame(struct w9968cf_device* cam,
			  struct w9968cf_frame_t* fr)
{
	void *pIn = fr->buffer, *pOut = cam->frame_vpp.buffer, *tmp;
	u16 w = cam->window.width,
	    h = cam->window.height,
	    d = cam->picture.depth,
	    fmt = cam->picture.palette,
	    rgb = cam->force_rgb,
	    hw_w = cam->hw_width,
	    hw_h = cam->hw_height,
	    hw_d = cam->hw_depth;
	int err = 0;

	#define _PSWAP(pIn, pOut) {tmp = (pIn); (pIn) = (pOut); (pOut) = tmp;}

	if (cam->vpp_flag & VPP_DECOMPRESSION) {
		memcpy(pOut, pIn, fr->length);
		_PSWAP(pIn, pOut)
		err = w9968cf_vpp->decode(pIn, fr->length, hw_w, hw_h, pOut);
		PDBGG("Compressed frame length: %lu",(unsigned long)fr->length)
		fr->length = (hw_w*hw_h*hw_d)/8;
		_PSWAP(pIn, pOut)
		if (err) {
			DBG(4, "An error occurred while decoding the frame: "
			       "%s", symbolic(decoder_errlist, err))
			return err;
		} else
			DBG(6, "Frame decoded")
	}

	if (cam->vpp_flag & VPP_SWAP_YUV_BYTES) {
		w9968cf_vpp->swap_yuvbytes(pIn, fr->length);
		DBG(6, "Original UYVY component ordering changed")
	}

	if (cam->vpp_flag & VPP_UPSCALE) {
		w9968cf_vpp->scale_up(pIn, pOut, hw_w, hw_h, hw_d, w, h);
		fr->length = (w*h*hw_d)/8;
		_PSWAP(pIn, pOut)
		DBG(6, "Vertical up-scaling done: %u,%u,%ubpp->%u,%u",
		    hw_w, hw_h, hw_d, w, h)
	}

	if (cam->vpp_flag & VPP_UYVY_TO_RGBX) {
		w9968cf_vpp->uyvy_to_rgbx(pIn, fr->length, pOut, fmt, rgb);
		fr->length = (w*h*d)/8;
		_PSWAP(pIn, pOut)
		DBG(6, "UYVY-16bit to %s conversion done",
		    symbolic(v4l1_plist, fmt))
	}

	if (pOut == fr->buffer)
		memcpy(fr->buffer, cam->frame_vpp.buffer, fr->length);

	return 0;
}


/****************************************************************************
 * Image sensor control routines                                            *
 ****************************************************************************/

static int
w9968cf_sensor_set_control(struct w9968cf_device* cam, int cid, int val)
{
	struct ovcamchip_control ctl;
	int err;

	ctl.id = cid;
	ctl.value = val;

	err = w9968cf_sensor_cmd(cam, OVCAMCHIP_CMD_S_CTRL, &ctl);

	return err;
}


static int
w9968cf_sensor_get_control(struct w9968cf_device* cam, int cid, int* val)
{
	struct ovcamchip_control ctl;
	int err;

	ctl.id = cid;

	err = w9968cf_sensor_cmd(cam, OVCAMCHIP_CMD_G_CTRL, &ctl);
	if (!err)
		*val = ctl.value;

	return err;
}


static int
w9968cf_sensor_cmd(struct w9968cf_device* cam, unsigned int cmd, void* arg)
{
	struct i2c_client* c = cam->sensor_client;
	int rc = 0;

	if (!c || !c->driver || !c->driver->command)
		return -EINVAL;

	rc = c->driver->command(c, cmd, arg);
	/* The I2C driver returns -EPERM on non-supported controls */
	return (rc < 0 && rc != -EPERM) ? rc : 0;
}


/*--------------------------------------------------------------------------
  Update some settings of the image sensor.
  Returns: 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_sensor_update_settings(struct w9968cf_device* cam)
{
	int err = 0;

	/* Auto brightness */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_AUTOBRIGHT,
					 cam->auto_brt);
	if (err)
		return err;

	/* Auto exposure */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_AUTOEXP,
					 cam->auto_exp);
	if (err)
		return err;

	/* Banding filter */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_BANDFILT,
					 cam->bandfilt);
	if (err)
		return err;

	/* Light frequency */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_FREQ,
					 cam->lightfreq);
	if (err)
		return err;

	/* Back light */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_BACKLIGHT,
					 cam->backlight);
	if (err)
		return err;

	/* Mirror */
	err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_MIRROR,
					 cam->mirror);
	if (err)
		return err;

	return 0;
}


/*--------------------------------------------------------------------------
  Get some current picture settings from the image sensor and update the
  internal 'picture' structure of the camera.
  Returns: 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_sensor_get_picture(struct w9968cf_device* cam)
{
	int err, v;

	err = w9968cf_sensor_get_control(cam, OVCAMCHIP_CID_CONT, &v);
	if (err)
		return err;
	cam->picture.contrast = v;

	err = w9968cf_sensor_get_control(cam, OVCAMCHIP_CID_BRIGHT, &v);
	if (err)
		return err;
	cam->picture.brightness = v;

	err = w9968cf_sensor_get_control(cam, OVCAMCHIP_CID_SAT, &v);
	if (err)
		return err;
	cam->picture.colour = v;

	err = w9968cf_sensor_get_control(cam, OVCAMCHIP_CID_HUE, &v);
	if (err)
		return err;
	cam->picture.hue = v;

	DBG(5, "Got picture settings from the image sensor")

	PDBGG("Brightness, contrast, hue, colour, whiteness are "
	      "%u,%u,%u,%u,%u", cam->picture.brightness,cam->picture.contrast,
	      cam->picture.hue, cam->picture.colour, cam->picture.whiteness)

	return 0;
}


/*--------------------------------------------------------------------------
  Update picture settings of the image sensor.
  Returns: 0 on success, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int
w9968cf_sensor_update_picture(struct w9968cf_device* cam,
			      struct video_picture pict)
{
	int err = 0;

	if ((!cam->sensor_initialized)
	    || pict.contrast != cam->picture.contrast) {
		err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_CONT,
						 pict.contrast);
		if (err)
			goto fail;
		DBG(4, "Contrast changed from %u to %u",
		    cam->picture.contrast, pict.contrast)
		cam->picture.contrast = pict.contrast;
	}

	if (((!cam->sensor_initialized) ||
	    pict.brightness != cam->picture.brightness) && (!cam->auto_brt)) {
		err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_BRIGHT,
						 pict.brightness);
		if (err)
			goto fail;
		DBG(4, "Brightness changed from %u to %u",
		    cam->picture.brightness, pict.brightness)
		cam->picture.brightness = pict.brightness;
	}

	if ((!cam->sensor_initialized) || pict.colour != cam->picture.colour) {
		err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_SAT,
						 pict.colour);
		if (err)
			goto fail;
		DBG(4, "Colour changed from %u to %u",
		    cam->picture.colour, pict.colour)
		cam->picture.colour = pict.colour;
	}

	if ((!cam->sensor_initialized) || pict.hue != cam->picture.hue) {
		err = w9968cf_sensor_set_control(cam, OVCAMCHIP_CID_HUE,
						 pict.hue);
		if (err)
			goto fail;
		DBG(4, "Hue changed from %u to %u",
		    cam->picture.hue, pict.hue)
		cam->picture.hue = pict.hue;
	}

	return 0;

fail:
	DBG(4, "Failed to change sensor picture setting")
	return err;
}


/****************************************************************************
 * Camera configuration                                                     *
 ****************************************************************************/

/*--------------------------------------------------------------------------
  This function is called when a supported image sensor is detected.
  Return 0 if the initialization succeeds, a negative number otherwise.
  --------------------------------------------------------------------------*/
static int w9968cf_sensor_init(struct w9968cf_device* cam)
{
	int err = 0;

	if ((err = w9968cf_sensor_cmd(cam, OVCAMCHIP_CMD_INITIALIZE,
				      &cam->monochrome)))
		goto error;

	if ((err = w9968cf_sensor_cmd(cam, OVCAMCHIP_CMD_Q_SUBTYPE,
				      &cam->sensor)))
		goto error;

	/* NOTE: Make sure width and height are a multiple of 16 */
	switch (cam->sensor_client->addr) {
		case OV6xx0_SID:
			cam->maxwidth = 352;
			cam->maxheight = 288;
			cam->minwidth = 64;
			cam->minheight = 48;
			break;
		case OV7xx0_SID:
			cam->maxwidth = 640;
			cam->maxheight = 480;
			cam->minwidth = 64;
			cam->minheight = 48;
			break;
		default:
			DBG(1, "Not supported image sensor detected for %s",
			    symbolic(camlist, cam->id))
			return -EINVAL;
	}

	/* These values depend on the ones in the ovxxx0.c sources */
	switch (cam->sensor) {
		case CC_OV7620:
			cam->start_cropx = 287;
			cam->start_cropy = 35;
			/* Seems to work around a bug in the image sensor */
			cam->vs_polarity = 1;
			cam->hs_polarity = 1;
			break;
		default:
			cam->start_cropx = 320;
			cam->start_cropy = 35;
			cam->vs_polarity = 1;
			cam->hs_polarity = 0;
	}

	if ((err = w9968cf_sensor_update_settings(cam)))
		goto error;

	if ((err = w9968cf_sensor_update_picture(cam, cam->picture)))
		goto error;

	cam->sensor_initialized = 1;

	DBG(2, "%s image sensor initialized", symbolic(senlist, cam->sensor))
	return 0;

error:
	cam->sensor_initialized = 0;
	cam->sensor = CC_UNKNOWN;
	DBG(1, "Image sensor initialization failed for %s (/dev/video%d). "
	       "Try to detach and attach this device again",
	    symbolic(camlist, cam->id), cam->v4ldev->num)
	return err;
}


/*--------------------------------------------------------------------------
  Fill some basic fields in the main device data structure.
  This function is called once on w9968cf_usb_probe() for each recognized
  camera.
  --------------------------------------------------------------------------*/
static void
w9968cf_configure_camera(struct w9968cf_device* cam,
			 struct usb_device* udev,
			 enum w9968cf_model_id mod_id,
			 const unsigned short dev_nr)
{
	mutex_init(&cam->fileop_mutex);
	init_waitqueue_head(&cam->open);
	spin_lock_init(&cam->urb_lock);
	spin_lock_init(&cam->flist_lock);

	cam->users = 0;
	cam->disconnected = 0;
	cam->id = mod_id;
	cam->sensor = CC_UNKNOWN;
	cam->sensor_initialized = 0;

	/* Calculate the alternate setting number (from 1 to 16)
	   according to the 'packet_size' module parameter */
	if (packet_size[dev_nr] < W9968CF_MIN_PACKET_SIZE)
		packet_size[dev_nr] = W9968CF_MIN_PACKET_SIZE;
	for (cam->altsetting = 1;
	     packet_size[dev_nr] < wMaxPacketSize[cam->altsetting-1];
	     cam->altsetting++);

	cam->max_buffers = (max_buffers[dev_nr] < 2 ||
			    max_buffers[dev_nr] > W9968CF_MAX_BUFFERS)
			   ? W9968CF_BUFFERS : (u8)max_buffers[dev_nr];

	cam->double_buffer = (double_buffer[dev_nr] == 0 ||
			      double_buffer[dev_nr] == 1)
			     ? (u8)double_buffer[dev_nr]:W9968CF_DOUBLE_BUFFER;

	cam->clamping = (clamping[dev_nr] == 0 || clamping[dev_nr] == 1)
			? (u8)clamping[dev_nr] : W9968CF_CLAMPING;

	cam->filter_type = (filter_type[dev_nr] == 0 ||
			    filter_type[dev_nr] == 1 ||
			    filter_type[dev_nr] == 2)
			   ? (u8)filter_type[dev_nr] : W9968CF_FILTER_TYPE;

	cam->capture = 1;

	cam->largeview = (largeview[dev_nr] == 0 || largeview[dev_nr] == 1)
			 ? (u8)largeview[dev_nr] : W9968CF_LARGEVIEW;

	cam->decompression = (decompression[dev_nr] == 0 ||
			      decompression[dev_nr] == 1 ||
			      decompression[dev_nr] == 2)
			     ? (u8)decompression[dev_nr]:W9968CF_DECOMPRESSION;

	cam->upscaling = (upscaling[dev_nr] == 0 ||
			  upscaling[dev_nr] == 1)
			 ? (u8)upscaling[dev_nr] : W9968CF_UPSCALING;

	cam->auto_brt = (autobright[dev_nr] == 0 || autobright[dev_nr] == 1)
			? (u8)autobright[dev_nr] : W9968CF_AUTOBRIGHT;

	cam->auto_exp = (autoexp[dev_nr] == 0 || autoexp[dev_nr] == 1)
			? (u8)autoexp[dev_nr] : W9968CF_AUTOEXP;

	cam->lightfreq = (lightfreq[dev_nr] == 50 || lightfreq[dev_nr] == 60)
			 ? (u8)lightfreq[dev_nr] : W9968CF_LIGHTFREQ;

	cam->bandfilt = (bandingfilter[dev_nr] == 0 ||
			 bandingfilter[dev_nr] == 1)
			? (u8)bandingfilter[dev_nr] : W9968CF_BANDINGFILTER;

	cam->backlight = (backlight[dev_nr] == 0 || backlight[dev_nr] == 1)
			 ? (u8)backlight[dev_nr] : W9968CF_BACKLIGHT;

	cam->clockdiv = (clockdiv[dev_nr] == -1 || clockdiv[dev_nr] >= 0)
			? (s8)clockdiv[dev_nr] : W9968CF_CLOCKDIV;

	cam->mirror = (mirror[dev_nr] == 0 || mirror[dev_nr] == 1)
		      ? (u8)mirror[dev_nr] : W9968CF_MIRROR;

	cam->monochrome = (monochrome[dev_nr] == 0 || monochrome[dev_nr] == 1)
			  ? monochrome[dev_nr] : W9968CF_MONOCHROME;

	cam->picture.brightness = (u16)brightness[dev_nr];
	cam->picture.hue = (u16)hue[dev_nr];
	cam->picture.colour = (u16)colour[dev_nr];
	cam->picture.contrast = (u16)contrast[dev_nr];
	cam->picture.whiteness = (u16)whiteness[dev_nr];
	if (w9968cf_valid_palette((u16)force_palette[dev_nr])) {
		cam->picture.palette = (u16)force_palette[dev_nr];
		cam->force_palette = 1;
	} else {
		cam->force_palette = 0;
		if (cam->decompression == 0)
			cam->picture.palette = W9968CF_PALETTE_DECOMP_OFF;
		else if (cam->decompression == 1)
			cam->picture.palette = W9968CF_PALETTE_DECOMP_FORCE;
		else
			cam->picture.palette = W9968CF_PALETTE_DECOMP_ON;
	}
	cam->picture.depth = w9968cf_valid_depth(cam->picture.palette);

	cam->force_rgb = (force_rgb[dev_nr] == 0 || force_rgb[dev_nr] == 1)
			 ? (u8)force_rgb[dev_nr] : W9968CF_FORCE_RGB;

	cam->window.x = 0;
	cam->window.y = 0;
	cam->window.width = W9968CF_WIDTH;
	cam->window.height = W9968CF_HEIGHT;
	cam->window.chromakey = 0;
	cam->window.clipcount = 0;
	cam->window.flags = 0;

	DBG(3, "%s configured with settings #%u:",
	    symbolic(camlist, cam->id), dev_nr)

	DBG(3, "- Data packet size for USB isochrnous transfer: %u bytes",
	    wMaxPacketSize[cam->altsetting-1])

	DBG(3, "- Number of requested video frame buffers: %u",
	    cam->max_buffers)

	if (cam->double_buffer)
		DBG(3, "- Hardware double buffering enabled")
	else
		DBG(3, "- Hardware double buffering disabled")

	if (cam->filter_type == 0)
		DBG(3, "- Video filtering disabled")
	else if (cam->filter_type == 1)
		DBG(3, "- Video filtering enabled: type 1-2-1")
	else if (cam->filter_type == 2)
		DBG(3, "- Video filtering enabled: type 2-3-6-3-2")

	if (cam->clamping)
		DBG(3, "- Video data clamping (CCIR-601 format) enabled")
	else
		DBG(3, "- Video data clamping (CCIR-601 format) disabled")

	if (cam->largeview)
		DBG(3, "- Large view enabled")
	else
		DBG(3, "- Large view disabled")

	if ((cam->decompression) == 0 && (!cam->force_palette))
		DBG(3, "- Decompression disabled")
	else if ((cam->decompression) == 1 && (!cam->force_palette))
		DBG(3, "- Decompression forced")
	else if ((cam->decompression) == 2 && (!cam->force_palette))
		DBG(3, "- Decompression allowed")

	if (cam->upscaling)
		DBG(3, "- Software image scaling enabled")
	else
		DBG(3, "- Software image scaling disabled")

	if (cam->force_palette)
		DBG(3, "- Image palette forced to %s",
		    symbolic(v4l1_plist, cam->picture.palette))

	if (cam->force_rgb)
		DBG(3, "- RGB component ordering will be used instead of BGR")

	if (cam->auto_brt)
		DBG(3, "- Auto brightness enabled")
	else
		DBG(3, "- Auto brightness disabled")

	if (cam->auto_exp)
		DBG(3, "- Auto exposure enabled")
	else
		DBG(3, "- Auto exposure disabled")

	if (cam->backlight)
		DBG(3, "- Backlight exposure algorithm enabled")
	else
		DBG(3, "- Backlight exposure algorithm disabled")

	if (cam->mirror)
		DBG(3, "- Mirror enabled")
	else
		DBG(3, "- Mirror disabled")

	if (cam->bandfilt)
		DBG(3, "- Banding filter enabled")
	else
		DBG(3, "- Banding filter disabled")

	DBG(3, "- Power lighting frequency: %u", cam->lightfreq)

	if (cam->clockdiv == -1)
		DBG(3, "- Automatic clock divisor enabled")
	else
		DBG(3, "- Clock divisor: %d", cam->clockdiv)

	if (cam->monochrome)
		DBG(3, "- Image sensor used as monochrome")
	else
		DBG(3, "- Image sensor not used as monochrome")
}


/*--------------------------------------------------------------------------
  If the video post-processing module is not loaded, some parameters
  must be overridden.
  --------------------------------------------------------------------------*/
static void w9968cf_adjust_configuration(struct w9968cf_device* cam)
{
	if (!w9968cf_vpp) {
		if (cam->decompression == 1) {
			cam->decompression = 2;
			DBG(2, "Video post-processing module not found: "
			       "'decompression' parameter forced to 2")
		}
		if (cam->upscaling) {
			cam->upscaling = 0;
			DBG(2, "Video post-processing module not found: "
			       "'upscaling' parameter forced to 0")
		}
		if (cam->picture.palette != VIDEO_PALETTE_UYVY) {
			cam->force_palette = 0;
			DBG(2, "Video post-processing module not found: "
			       "'force_palette' parameter forced to 0")
		}
		cam->picture.palette = VIDEO_PALETTE_UYVY;
		cam->picture.depth = w9968cf_valid_depth(cam->picture.palette);
	}
}


/*--------------------------------------------------------------------------
  Release the resources used by the driver.
  This function is called on disconnect
  (or on close if deallocation has been deferred)
  --------------------------------------------------------------------------*/
static void w9968cf_release_resources(struct w9968cf_device* cam)
{
	mutex_lock(&w9968cf_devlist_mutex);

	DBG(2, "V4L device deregistered: /dev/video%d", cam->v4ldev->num)

	video_unregister_device(cam->v4ldev);
	list_del(&cam->v4llist);
	i2c_del_adapter(&cam->i2c_adapter);
	w9968cf_deallocate_memory(cam);
	kfree(cam->control_buffer);
	kfree(cam->data_buffer);

	mutex_unlock(&w9968cf_devlist_mutex);
}


/****************************************************************************
 * Video4Linux interface                                                    *
 ****************************************************************************/

static int w9968cf_open(struct inode* inode, struct file* filp)
{
	struct w9968cf_device* cam;
	int err;

	/* This the only safe way to prevent race conditions with disconnect */
	if (!down_read_trylock(&w9968cf_disconnect))
		return -EAGAIN;

	cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));

	mutex_lock(&cam->dev_mutex);

	if (cam->sensor == CC_UNKNOWN) {
		DBG(2, "No supported image sensor has been detected by the "
		       "'ovcamchip' module for the %s (/dev/video%d). Make "
		       "sure it is loaded *before* (re)connecting the camera.",
		    symbolic(camlist, cam->id), cam->v4ldev->num)
		mutex_unlock(&cam->dev_mutex);
		up_read(&w9968cf_disconnect);
		return -ENODEV;
	}

	if (cam->users) {
		DBG(2, "%s (/dev/video%d) has been already occupied by '%s'",
		    symbolic(camlist, cam->id), cam->v4ldev->num, cam->command)
		if ((filp->f_flags & O_NONBLOCK)||(filp->f_flags & O_NDELAY)) {
			mutex_unlock(&cam->dev_mutex);
			up_read(&w9968cf_disconnect);
			return -EWOULDBLOCK;
		}
		mutex_unlock(&cam->dev_mutex);
		err = wait_event_interruptible_exclusive(cam->open,
							 cam->disconnected ||
							 !cam->users);
		if (err) {
			up_read(&w9968cf_disconnect);
			return err;
		}
		if (cam->disconnected) {
			up_read(&w9968cf_disconnect);
			return -ENODEV;
		}
		mutex_lock(&cam->dev_mutex);
	}

	DBG(5, "Opening '%s', /dev/video%d ...",
	    symbolic(camlist, cam->id), cam->v4ldev->num)

	cam->streaming = 0;
	cam->misconfigured = 0;

	w9968cf_adjust_configuration(cam);

	if ((err = w9968cf_allocate_memory(cam)))
		goto deallocate_memory;

	if ((err = w9968cf_init_chip(cam)))
		goto deallocate_memory;

	if ((err = w9968cf_start_transfer(cam)))
		goto deallocate_memory;

	filp->private_data = cam;

	cam->users++;
	strcpy(cam->command, current->comm);

	init_waitqueue_head(&cam->wait_queue);

	DBG(5, "Video device is open")

	mutex_unlock(&cam->dev_mutex);
	up_read(&w9968cf_disconnect);

	return 0;

deallocate_memory:
	w9968cf_deallocate_memory(cam);
	DBG(2, "Failed to open the video device")
	mutex_unlock(&cam->dev_mutex);
	up_read(&w9968cf_disconnect);
	return err;
}


static int w9968cf_release(struct inode* inode, struct file* filp)
{
	struct w9968cf_device* cam;

	cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));

	mutex_lock(&cam->dev_mutex); /* prevent disconnect() to be called */

	w9968cf_stop_transfer(cam);

	if (cam->disconnected) {
		w9968cf_release_resources(cam);
		mutex_unlock(&cam->dev_mutex);
		kfree(cam);
		return 0;
	}

	cam->users--;
	w9968cf_deallocate_memory(cam);
	wake_up_interruptible_nr(&cam->open, 1);

	DBG(5, "Video device closed")
	mutex_unlock(&cam->dev_mutex);
	return 0;
}


static ssize_t
w9968cf_read(struct file* filp, char __user * buf, size_t count, loff_t* f_pos)
{
	struct w9968cf_device* cam;
	struct w9968cf_frame_t* fr;
	int err = 0;

	cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));

	if (filp->f_flags & O_NONBLOCK)
		return -EWOULDBLOCK;

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

	if (cam->disconnected) {
		DBG(2, "Device not present")
		mutex_unlock(&cam->fileop_mutex);
		return -ENODEV;
	}

	if (cam->misconfigured) {
		DBG(2, "The camera is misconfigured. Close and open it again.")
		mutex_unlock(&cam->fileop_mutex);
		return -EIO;
	}

	if (!cam->frame[0].queued)
		w9968cf_push_frame(cam, 0);

	if (!cam->frame[1].queued)
		w9968cf_push_frame(cam, 1);

	err = wait_event_interruptible(cam->wait_queue,
				       cam->frame[0].status == F_READY ||
				       cam->frame[1].status == F_READY ||
				       cam->disconnected);
	if (err) {
		mutex_unlock(&cam->fileop_mutex);
		return err;
	}
	if (cam->disconnected) {
		mutex_unlock(&cam->fileop_mutex);
		return -ENODEV;
	}

	fr = (cam->frame[0].status == F_READY) ? &cam->frame[0]:&cam->frame[1];

	if (w9968cf_vpp)
		w9968cf_postprocess_frame(cam, fr);

	if (count > fr->length)
		count = fr->length;

	if (copy_to_user(buf, fr->buffer, count)) {
		fr->status = F_UNUSED;
		mutex_unlock(&cam->fileop_mutex);
		return -EFAULT;
	}
	*f_pos += count;

	fr->status = F_UNUSED;

	DBG(5, "%zu bytes read", count)

	mutex_unlock(&cam->fileop_mutex);
	return count;
}


static int w9968cf_mmap(struct file* filp, struct vm_area_struct *vma)
{
	struct w9968cf_device* cam = (struct w9968cf_device*)
				     video_get_drvdata(video_devdata(filp));
	unsigned long vsize = vma->vm_end - vma->vm_start,
		      psize = cam->nbuffers * cam->frame[0].size,
		      start = vma->vm_start,
		      pos = (unsigned long)cam->frame[0].buffer,
		      page;

	if (cam->disconnected) {
		DBG(2, "Device not present")
		return -ENODEV;
	}

	if (cam->misconfigured) {
		DBG(2, "The camera is misconfigured. Close and open it again")
		return -EIO;
	}

	PDBGG("mmapping %lu bytes...", vsize)

	if (vsize > psize - (vma->vm_pgoff << PAGE_SHIFT))
		return -EINVAL;

	while (vsize > 0) {
		page = vmalloc_to_pfn((void *)pos);
		if (remap_pfn_range(vma, start, page + vma->vm_pgoff,
						PAGE_SIZE, vma->vm_page_prot))
			return -EAGAIN;
		start += PAGE_SIZE;
		pos += PAGE_SIZE;
		vsize -= PAGE_SIZE;
	}

	DBG(5, "mmap method successfully called")
	return 0;
}


static int
w9968cf_ioctl(struct inode* inode, struct file* filp,
	      unsigned int cmd, unsigned long arg)
{
	struct w9968cf_device* cam;
	int err;

	cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));

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

	if (cam->disconnected) {
		DBG(2, "Device not present")
		mutex_unlock(&cam->fileop_mutex);
		return -ENODEV;
	}

	if (cam->misconfigured) {
		DBG(2, "The camera is misconfigured. Close and open it again.")
		mutex_unlock(&cam->fileop_mutex);
		return -EIO;
	}

	err = w9968cf_v4l_ioctl(inode, filp, cmd, (void __user *)arg);

	mutex_unlock(&cam->fileop_mutex);
	return err;
}


static int w9968cf_v4l_ioctl(struct inode* inode, struct file* filp,
			     unsigned int cmd, void __user * arg)
{
	struct w9968cf_device* cam;
	const char* v4l1_ioctls[] = {
		"?", "CGAP", "GCHAN", "SCHAN", "GTUNER", "STUNER",
		"GPICT", "SPICT", "CCAPTURE", "GWIN", "SWIN", "GFBUF",
		"SFBUF", "KEY", "GFREQ", "SFREQ", "GAUDIO", "SAUDIO",
		"SYNC", "MCAPTURE", "GMBUF", "GUNIT", "GCAPTURE", "SCAPTURE",
		"SPLAYMODE", "SWRITEMODE", "GPLAYINFO", "SMICROCODE",
		"GVBIFMT", "SVBIFMT"
	};

	#define V4L1_IOCTL(cmd) \
		((_IOC_NR((cmd)) < ARRAY_SIZE(v4l1_ioctls)) ? \
		v4l1_ioctls[_IOC_NR((cmd))] : "?")

	cam = (struct w9968cf_device*)video_get_drvdata(video_devdata(filp));

	switch (cmd) {

	case VIDIOCGCAP: /* get video capability */
	{
		struct video_capability cap = {
			.type = VID_TYPE_CAPTURE | VID_TYPE_SCALES,
			.channels = 1,
			.audios = 0,
			.minwidth = cam->minwidth,
			.minheight = cam->minheight,
		};
		sprintf(cap.name, "W996[87]CF USB Camera #%d",
			cam->v4ldev->num);
		cap.maxwidth = (cam->upscaling && w9968cf_vpp)
			       ? max((u16)W9968CF_MAX_WIDTH, cam->maxwidth)
				 : cam->maxwidth;
		cap.maxheight = (cam->upscaling && w9968cf_vpp)
				? max((u16)W9968CF_MAX_HEIGHT, cam->maxheight)
				  : cam->maxheight;

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

		DBG(5, "VIDIOCGCAP successfully called")
		return 0;
	}

	case VIDIOCGCHAN: /* get video channel informations */
	{
		struct video_channel chan;
		if (copy_from_user(&chan, arg, sizeof(chan)))
			return -EFAULT;

		if (chan.channel != 0)
			return -EINVAL;

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

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

		DBG(5, "VIDIOCGCHAN successfully called")
		return 0;
	}

	case VIDIOCSCHAN: /* set active channel */
	{
		struct video_channel chan;

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

		if (chan.channel != 0)
			return -EINVAL;

		DBG(5, "VIDIOCSCHAN successfully called")
		return 0;
	}

	case VIDIOCGPICT: /* get image properties of the picture */
	{
		if (w9968cf_sensor_get_picture(cam))
			return -EIO;

		if (copy_to_user(arg, &cam->picture, sizeof(cam->picture)))
			return -EFAULT;

		DBG(5, "VIDIOCGPICT successfully called")
		return 0;
	}

	case VIDIOCSPICT: /* change picture settings */
	{
		struct video_picture pict;
		int err = 0;

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

		if ( (cam->force_palette || !w9968cf_vpp)
		     && pict.palette != cam->picture.palette ) {
			DBG(4, "Palette %s rejected: only %s is allowed",
			    symbolic(v4l1_plist, pict.palette),
			    symbolic(v4l1_plist, cam->picture.palette))
			return -EINVAL;
		}

		if (!w9968cf_valid_palette(pict.palette)) {
			DBG(4, "Palette %s not supported. VIDIOCSPICT failed",
			    symbolic(v4l1_plist, pict.palette))
			return -EINVAL;
		}

		if (!cam->force_palette) {
		   if (cam->decompression == 0) {
		      if (w9968cf_need_decompression(pict.palette)) {
			 DBG(4, "Decompression disabled: palette %s is not "
				"allowed. VIDIOCSPICT failed",
			     symbolic(v4l1_plist, pict.palette))
			 return -EINVAL;
		      }
		   } else if (cam->decompression == 1) {
		      if (!w9968cf_need_decompression(pict.palette)) {
			 DBG(4, "Decompression forced: palette %s is not "
				"allowed. VIDIOCSPICT failed",
			     symbolic(v4l1_plist, pict.palette))
			 return -EINVAL;
		      }
		   }
		}

		if (pict.depth != w9968cf_valid_depth(pict.palette)) {
			DBG(4, "Requested depth %u bpp is not valid for %s "
			       "palette: ignored and changed to %u bpp",
			    pict.depth, symbolic(v4l1_plist, pict.palette),
			    w9968cf_valid_depth(pict.palette))
			pict.depth = w9968cf_valid_depth(pict.palette);
		}

		if (pict.palette != cam->picture.palette) {
			if(*cam->requested_frame
			   || cam->frame_current->queued) {
				err = wait_event_interruptible
				      ( cam->wait_queue,
					cam->disconnected ||
					(!*cam->requested_frame &&
					 !cam->frame_current->queued) );
				if (err)
					return err;
				if (cam->disconnected)
					return -ENODEV;
			}

			if (w9968cf_stop_transfer(cam))
				goto ioctl_fail;

			if (w9968cf_set_picture(cam, pict))
				goto ioctl_fail;

			if (w9968cf_start_transfer(cam))
				goto ioctl_fail;

		} else if (w9968cf_sensor_update_picture(cam, pict))
			return -EIO;


		DBG(5, "VIDIOCSPICT successfully called")
		return 0;
	}

	case VIDIOCSWIN: /* set capture area */
	{
		struct video_window win;
		int err = 0;

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

		DBG(6, "VIDIOCSWIN called: clipcount=%d, flags=%u, "
		       "x=%u, y=%u, %ux%u", win.clipcount, win.flags,
		    win.x, win.y, win.width, win.height)

		if (win.clipcount != 0 || win.flags != 0)
			return -EINVAL;

		if ((err = w9968cf_adjust_window_size(cam, (u16*)&win.width,
						      (u16*)&win.height))) {
			DBG(4, "Resolution not supported (%ux%u). "
			       "VIDIOCSWIN failed", win.width, win.height)
			return err;
		}

		if (win.x != cam->window.x ||
		    win.y != cam->window.y ||
		    win.width != cam->window.width ||
		    win.height != cam->window.height) {
			if(*cam->requested_frame
			   || cam->frame_current->queued) {
				err = wait_event_interruptible
				      ( cam->wait_queue,
					cam->disconnected ||
					(!*cam->requested_frame &&
					 !cam->frame_current->queued) );
				if (err)
					return err;
				if (cam->disconnected)
					return -ENODEV;
			}

			if (w9968cf_stop_transfer(cam))
				goto ioctl_fail;

			/* This _must_ be called before set_window() */
			if (w9968cf_set_picture(cam, cam->picture))
				goto ioctl_fail;

			if (w9968cf_set_window(cam, win))
				goto ioctl_fail;

			if (w9968cf_start_transfer(cam))
				goto ioctl_fail;
		}

		DBG(5, "VIDIOCSWIN successfully called. ")
		return 0;
	}

	case VIDIOCGWIN: /* get current window properties */
	{
		if (copy_to_user(arg,&cam->window,sizeof(struct video_window)))
			return -EFAULT;

		DBG(5, "VIDIOCGWIN successfully called")
		return 0;
	}

	case VIDIOCGMBUF: /* request for memory (mapped) buffer */
	{
		struct video_mbuf mbuf;
		u8 i;

		mbuf.size = cam->nbuffers * cam->frame[0].size;
		mbuf.frames = cam->nbuffers;
		for (i = 0; i < cam->nbuffers; i++)
			mbuf.offsets[i] = (unsigned long)cam->frame[i].buffer -
					  (unsigned long)cam->frame[0].buffer;

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

		DBG(5, "VIDIOCGMBUF successfully called")
		return 0;
	}

	case VIDIOCMCAPTURE: /* start the capture to a frame */
	{
		struct video_mmap mmap;
		struct w9968cf_frame_t* fr;
		int err = 0;

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

		DBG(6, "VIDIOCMCAPTURE called: frame #%u, format=%s, %dx%d",
		    mmap.frame, symbolic(v4l1_plist, mmap.format),
		    mmap.width, mmap.height)

		if (mmap.frame >= cam->nbuffers) {
			DBG(4, "Invalid frame number (%u). "
			       "VIDIOCMCAPTURE failed", mmap.frame)
			return -EINVAL;
		}

		if (mmap.format!=cam->picture.palette &&
		    (cam->force_palette || !w9968cf_vpp)) {
			DBG(4, "Palette %s rejected: only %s is allowed",
			    symbolic(v4l1_plist, mmap.format),
			    symbolic(v4l1_plist, cam->picture.palette))
			return -EINVAL;
		}

		if (!w9968cf_valid_palette(mmap.format)) {
			DBG(4, "Palette %s not supported. "
			       "VIDIOCMCAPTURE failed",
			    symbolic(v4l1_plist, mmap.format))
			return -EINVAL;
		}

		if (!cam->force_palette) {
		   if (cam->decompression == 0) {
		      if (w9968cf_need_decompression(mmap.format)) {
			 DBG(4, "Decompression disabled: palette %s is not "
				"allowed. VIDIOCSPICT failed",
			     symbolic(v4l1_plist, mmap.format))
			 return -EINVAL;
		      }
		   } else if (cam->decompression == 1) {
		      if (!w9968cf_need_decompression(mmap.format)) {
			 DBG(4, "Decompression forced: palette %s is not "
				"allowed. VIDIOCSPICT failed",
			     symbolic(v4l1_plist, mmap.format))
			 return -EINVAL;
		      }
		   }
		}

		if ((err = w9968cf_adjust_window_size(cam, (u16*)&mmap.width,
						      (u16*)&mmap.height))) {
			DBG(4, "Resolution not supported (%dx%d). "
			       "VIDIOCMCAPTURE failed",
			    mmap.width, mmap.height)
			return err;
		}

		fr = &cam->frame[mmap.frame];

		if (mmap.width  != cam->window.width ||
		    mmap.height != cam->window.height ||
		    mmap.format != cam->picture.palette) {

			struct video_window win;
			struct video_picture pict;

			if(*cam->requested_frame
			   || cam->frame_current->queued) {
				DBG(6, "VIDIOCMCAPTURE. Change settings for "
				       "frame #%u: %dx%d, format %s. Wait...",
				    mmap.frame, mmap.width, mmap.height,
				    symbolic(v4l1_plist, mmap.format))
				err = wait_event_interruptible
				      ( cam->wait_queue,
					cam->disconnected ||
					(!*cam->requested_frame &&
					 !cam->frame_current->queued) );
				if (err)
					return err;
				if (cam->disconnected)
					return -ENODEV;
			}

			memcpy(&win, &cam->window, sizeof(win));
			memcpy(&pict, &cam->picture, sizeof(pict));
			win.width = mmap.width;
			win.height = mmap.height;
			pict.palette = mmap.format;

			if (w9968cf_stop_transfer(cam))
				goto ioctl_fail;

			/* This before set_window */
			if (w9968cf_set_picture(cam, pict))
				goto ioctl_fail;

			if (w9968cf_set_window(cam, win))
				goto ioctl_fail;

			if (w9968cf_start_transfer(cam))
				goto ioctl_fail;

		} else 	if (fr->queued) {

			DBG(6, "Wait until frame #%u is free", mmap.frame)

			err = wait_event_interruptible(cam->wait_queue,
						       cam->disconnected ||
						       (!fr->queued));
			if (err)
				return err;
			if (cam->disconnected)
				return -ENODEV;
		}

		w9968cf_push_frame(cam, mmap.frame);
		DBG(5, "VIDIOCMCAPTURE(%u): successfully called", mmap.frame)
		return 0;
	}

	case VIDIOCSYNC: /* wait until the capture of a frame is finished */
	{
		unsigned int f_num;
		struct w9968cf_frame_t* fr;
		int err = 0;

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

		if (f_num >= cam->nbuffers) {
			DBG(4, "Invalid frame number (%u). "
			       "VIDIOCMCAPTURE failed", f_num)
			return -EINVAL;
		}

		DBG(6, "VIDIOCSYNC called for frame #%u", f_num)

		fr = &cam->frame[f_num];

		switch (fr->status) {
		case F_UNUSED:
			if (!fr->queued) {
				DBG(4, "VIDIOSYNC: Frame #%u not requested!",
				    f_num)
				return -EFAULT;
			}
		case F_ERROR:
		case F_GRABBING:
			err = wait_event_interruptible(cam->wait_queue,
						       (fr->status == F_READY)
						       || cam->disconnected);
			if (err)
				return err;
			if (cam->disconnected)
				return -ENODEV;
			break;
		case F_READY:
			break;
		}

		if (w9968cf_vpp)
			w9968cf_postprocess_frame(cam, fr);

		fr->status = F_UNUSED;

		DBG(5, "VIDIOCSYNC(%u) successfully called", f_num)
		return 0;
	}

	case VIDIOCGUNIT:/* report the unit numbers of the associated devices*/
	{
		struct video_unit unit = {
			.video = cam->v4ldev->minor,
			.vbi = VIDEO_NO_UNIT,
			.radio = VIDEO_NO_UNIT,
			.audio = VIDEO_NO_UNIT,
			.teletext = VIDEO_NO_UNIT,
		};

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

		DBG(5, "VIDIOCGUNIT successfully called")
		return 0;
	}

	case VIDIOCKEY:
		return 0;

	case VIDIOCGFBUF:
	{
		if (clear_user(arg, sizeof(struct video_buffer)))
			return -EFAULT;

		DBG(5, "VIDIOCGFBUF successfully called")
		return 0;
	}

	case VIDIOCGTUNER:
	{
		struct video_tuner tuner;
		if (copy_from_user(&tuner, arg, sizeof(tuner)))
			return -EFAULT;

		if (tuner.tuner != 0)
			return -EINVAL;

		strcpy(tuner.name, "no_tuner");
		tuner.rangelow = 0;
		tuner.rangehigh = 0;
		tuner.flags = VIDEO_TUNER_NORM;
		tuner.mode = VIDEO_MODE_AUTO;
		tuner.signal = 0xffff;

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

		DBG(5, "VIDIOCGTUNER successfully called")
		return 0;
	}

	case VIDIOCSTUNER:
	{
		struct video_tuner tuner;
		if (copy_from_user(&tuner, arg, sizeof(tuner)))
			return -EFAULT;

		if (tuner.tuner != 0)
			return -EINVAL;

		if (tuner.mode != VIDEO_MODE_AUTO)
			return -EINVAL;

		DBG(5, "VIDIOCSTUNER successfully called")
		return 0;
	}

	case VIDIOCSFBUF:
	case VIDIOCCAPTURE:
	case VIDIOCGFREQ:
	case VIDIOCSFREQ:
	case VIDIOCGAUDIO:
	case VIDIOCSAUDIO:
	case VIDIOCSPLAYMODE:
	case VIDIOCSWRITEMODE:
	case VIDIOCGPLAYINFO:
	case VIDIOCSMICROCODE:
	case VIDIOCGVBIFMT:
	case VIDIOCSVBIFMT:
		DBG(4, "Unsupported V4L1 IOCtl: VIDIOC%s "
		       "(type 0x%01X, "
		       "n. 0x%01X, "
		       "dir. 0x%01X, "
		       "size 0x%02X)",
		    V4L1_IOCTL(cmd),
		    _IOC_TYPE(cmd),_IOC_NR(cmd),_IOC_DIR(cmd),_IOC_SIZE(cmd))

		return -EINVAL;

	default:
		DBG(4, "Invalid V4L1 IOCtl: VIDIOC%s "
		       "type 0x%01X, "
		       "n. 0x%01X, "
		       "dir. 0x%01X, "
		       "size 0x%02X",
		    V4L1_IOCTL(cmd),
		    _IOC_TYPE(cmd),_IOC_NR(cmd),_IOC_DIR(cmd),_IOC_SIZE(cmd))

		return -ENOIOCTLCMD;

	} /* end of switch */

ioctl_fail:
	cam->misconfigured = 1;
	DBG(1, "VIDIOC%s failed because of hardware problems. "
	       "To use the camera, close and open it again.", V4L1_IOCTL(cmd))
	return -EFAULT;
}


static const struct file_operations w9968cf_fops = {
	.owner =   THIS_MODULE,
	.open =    w9968cf_open,
	.release = w9968cf_release,
	.read =    w9968cf_read,
	.ioctl =   w9968cf_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = v4l_compat_ioctl32,
#endif
	.mmap =    w9968cf_mmap,
	.llseek =  no_llseek,
};


/****************************************************************************
 * USB probe and V4L registration, disconnect and id_table[] definition     *
 ****************************************************************************/

static int
w9968cf_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
{
	struct usb_device *udev = interface_to_usbdev(intf);
	struct w9968cf_device* cam;
	int err = 0;
	enum w9968cf_model_id mod_id;
	struct list_head* ptr;
	u8 sc = 0; /* number of simultaneous cameras */
	static unsigned short dev_nr; /* 0 - we are handling device number n */

	if (le16_to_cpu(udev->descriptor.idVendor)  == winbond_id_table[0].idVendor &&
	    le16_to_cpu(udev->descriptor.idProduct) == winbond_id_table[0].idProduct)
		mod_id = W9968CF_MOD_CLVBWGP; /* see camlist[] table */
	else if (le16_to_cpu(udev->descriptor.idVendor)  == winbond_id_table[1].idVendor &&
		 le16_to_cpu(udev->descriptor.idProduct) == winbond_id_table[1].idProduct)
		mod_id = W9968CF_MOD_GENERIC; /* see camlist[] table */
	else
		return -ENODEV;

	cam = (struct w9968cf_device*)
		  kzalloc(sizeof(struct w9968cf_device), GFP_KERNEL);
	if (!cam)
		return -ENOMEM;

	mutex_init(&cam->dev_mutex);
	mutex_lock(&cam->dev_mutex);

	cam->usbdev = udev;
	/* NOTE: a local copy is used to avoid possible race conditions */
	memcpy(&cam->dev, &udev->dev, sizeof(struct device));

	DBG(2, "%s detected", symbolic(camlist, mod_id))

	if (simcams > W9968CF_MAX_DEVICES)
		simcams = W9968CF_SIMCAMS;

	/* How many cameras are connected ? */
	mutex_lock(&w9968cf_devlist_mutex);
	list_for_each(ptr, &w9968cf_dev_list)
		sc++;
	mutex_unlock(&w9968cf_devlist_mutex);

	if (sc >= simcams) {
		DBG(2, "Device rejected: too many connected cameras "
		       "(max. %u)", simcams)
		err = -EPERM;
		goto fail;
	}


	/* Allocate 2 bytes of memory for camera control USB transfers */
	if (!(cam->control_buffer = kzalloc(2, GFP_KERNEL))) {
		DBG(1,"Couldn't allocate memory for camera control transfers")
		err = -ENOMEM;
		goto fail;
	}

	/* Allocate 8 bytes of memory for USB data transfers to the FSB */
	if (!(cam->data_buffer = kzalloc(8, GFP_KERNEL))) {
		DBG(1, "Couldn't allocate memory for data "
		       "transfers to the FSB")
		err = -ENOMEM;
		goto fail;
	}

	/* Register the V4L device */
	cam->v4ldev = video_device_alloc();
	if (!cam->v4ldev) {
		DBG(1, "Could not allocate memory for a V4L structure")
		err = -ENOMEM;
		goto fail;
	}

	strcpy(cam->v4ldev->name, symbolic(camlist, mod_id));
	cam->v4ldev->fops = &w9968cf_fops;
	cam->v4ldev->minor = video_nr[dev_nr];
	cam->v4ldev->release = video_device_release;
	video_set_drvdata(cam->v4ldev, cam);
	cam->v4ldev->parent = &cam->dev;

	err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
				    video_nr[dev_nr]);
	if (err) {
		DBG(1, "V4L device registration failed")
		if (err == -ENFILE && video_nr[dev_nr] == -1)
			DBG(2, "Couldn't find a free /dev/videoX node")
		video_nr[dev_nr] = -1;
		dev_nr = (dev_nr < W9968CF_MAX_DEVICES-1) ? dev_nr+1 : 0;
		goto fail;
	}

	DBG(2, "V4L device registered as /dev/video%d", cam->v4ldev->num)

	/* Set some basic constants */
	w9968cf_configure_camera(cam, udev, mod_id, dev_nr);

	/* Add a new entry into the list of V4L registered devices */
	mutex_lock(&w9968cf_devlist_mutex);
	list_add(&cam->v4llist, &w9968cf_dev_list);
	mutex_unlock(&w9968cf_devlist_mutex);
	dev_nr = (dev_nr < W9968CF_MAX_DEVICES-1) ? dev_nr+1 : 0;

	w9968cf_turn_on_led(cam);

	w9968cf_i2c_init(cam);

	usb_set_intfdata(intf, cam);
	mutex_unlock(&cam->dev_mutex);
	return 0;

fail: /* Free unused memory */
	kfree(cam->control_buffer);
	kfree(cam->data_buffer);
	if (cam->v4ldev)
		video_device_release(cam->v4ldev);
	mutex_unlock(&cam->dev_mutex);
	kfree(cam);
	return err;
}


static void w9968cf_usb_disconnect(struct usb_interface* intf)
{
	struct w9968cf_device* cam =
	   (struct w9968cf_device*)usb_get_intfdata(intf);

	down_write(&w9968cf_disconnect);

	if (cam) {
		/* Prevent concurrent accesses to data */
		mutex_lock(&cam->dev_mutex);

		cam->disconnected = 1;

		DBG(2, "Disconnecting %s...", symbolic(camlist, cam->id))

		wake_up_interruptible_all(&cam->open);

		if (cam->users) {
			DBG(2, "The device is open (/dev/video%d)! "
			       "Process name: %s. Deregistration and memory "
			       "deallocation are deferred on close.",
			    cam->v4ldev->num, cam->command)
			cam->misconfigured = 1;
			w9968cf_stop_transfer(cam);
			wake_up_interruptible(&cam->wait_queue);
		} else
			w9968cf_release_resources(cam);

		mutex_unlock(&cam->dev_mutex);

		if (!cam->users)
			kfree(cam);
	}

	up_write(&w9968cf_disconnect);
}


static struct usb_driver w9968cf_usb_driver = {
	.name =       "w9968cf",
	.id_table =   winbond_id_table,
	.probe =      w9968cf_usb_probe,
	.disconnect = w9968cf_usb_disconnect,
};


/****************************************************************************
 * Module init, exit and intermodule communication                          *
 ****************************************************************************/

static int __init w9968cf_module_init(void)
{
	int err;

	KDBG(2, W9968CF_MODULE_NAME" "W9968CF_MODULE_VERSION)
	KDBG(3, W9968CF_MODULE_AUTHOR)

	if (ovmod_load)
		request_module("ovcamchip");

	if ((err = usb_register(&w9968cf_usb_driver)))
		return err;

	return 0;
}


static void __exit w9968cf_module_exit(void)
{
	/* w9968cf_usb_disconnect() will be called */
	usb_deregister(&w9968cf_usb_driver);

	KDBG(2, W9968CF_MODULE_NAME" deregistered")
}


module_init(w9968cf_module_init);
module_exit(w9968cf_module_exit);