[PATCH] USB: Add ZC0301 Video4Linux2 driver

This patch adds a Video4Linux2 driver for ZC0301
Image Processor and Control Chip.
Signed-off-by: Luca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/usb/zc0301.txt

+
+                    ZC0301 Image Processor and Control Chip
+                                Driver for Linux
+                    =======================================
+
+                               - Documentation -
+
+
+Index
+=====
+1.  Copyright
+2.  Disclaimer
+3.  License
+4.  Overview and features
+5.  Module dependencies
+6.  Module loading
+7.  Module parameters
+8.  Supported devices
+9.  Notes for V4L2 application developers
+10. Contact information
+11. Credits
+
+
+1. Copyright
+============
+Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>
+
+
+2. Disclaimer
+=============
+This software is not developed or sponsored by Z-Star Microelectronics Corp.
+Trademarks are property of their respective owner.
+
+
+3. License
+==========
+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.
+
+
+4. Overview and features
+========================
+This driver supports the video interface of the devices mounting the ZC0301
+Image Processor and Control Chip.
+
+The driver relies on the Video4Linux2 and USB core modules. It has been
+designed to run properly on SMP systems as well.
+
+The latest version of the ZC0301 driver can be found at the following URL:
+http://www.linux-projects.org/
+
+Some of the features of the driver are:
+
+- full compliance with the Video4Linux2 API (see also "Notes for V4L2
+  application developers" paragraph);
+- available mmap or read/poll methods for video streaming through isochronous
+  data transfers;
+- automatic detection of image sensor;
+- video formats is standard JPEG in various compression qualities
+  (see also "Notes for V4L2 application developers" paragraph);
+- full support for the capabilities of every possible image sensors that can
+  be connected to the ZC0301 bridges, including, for istance, red, green,
+  blue and global gain adjustments and exposure control (see "Supported
+  devices" paragraph for details);
+- use of default color settings for sunlight conditions;
+- dynamic driver control thanks to various module parameters (see "Module
+  parameters" paragraph);
+- up to 64 cameras can be handled at the same time; they can be connected and
+  disconnected from the host many times without turning off the computer, if
+  the system supports hotplugging;
+
+
+5. Module dependencies
+======================
+For it to work properly, the driver needs kernel support for Video4Linux and
+USB.
+
+The following options of the kernel configuration file must be enabled and
+corresponding modules must be compiled:
+
+	# Multimedia devices
+	#
+	CONFIG_VIDEO_DEV=m
+
+	# USB support
+	#
+	CONFIG_USB=m
+
+In addition, depending on the hardware being used, the modules below are
+necessary:
+
+	# USB Host Controller Drivers
+	#
+	CONFIG_USB_EHCI_HCD=m
+	CONFIG_USB_UHCI_HCD=m
+	CONFIG_USB_OHCI_HCD=m
+
+The ZC0301 controller also provides a built-in microphone interface. It is
+supported by the USB Audio driver thanks to the ALSA API:
+
+	# Sound
+	#
+	CONFIG_SOUND=y
+
+	# Advanced Linux Sound Architecture
+	#
+	CONFIG_SND=m
+
+	# USB devices
+	#
+	CONFIG_SND_USB_AUDIO=m
+
+And finally:
+
+	# USB Multimedia devices
+	#
+	CONFIG_USB_ZC0301=m
+
+
+6. Module loading
+=================
+To use the driver, it is necessary to load the "zc0301" module into memory
+after every other module required: "videodev", "usbcore" and, depending on
+the USB host controller you have, "ehci-hcd", "uhci-hcd" or "ohci-hcd".
+
+Loading can be done as shown below:
+
+	[root@localhost home]# modprobe zc0301
+
+At this point the devices should be recognized. You can invoke "dmesg" to
+analyze kernel messages and verify that the loading process has gone well:
+
+	[user@localhost home]$ dmesg
+
+
+7. Module parameters
+====================
+Module parameters are listed below:
+-------------------------------------------------------------------------------
+Name:           video_nr
+Type:           short array (min = 0, max = 64)
+Syntax:         <-1|n[,...]>
+Description:    Specify V4L2 minor mode number:
+                -1 = use next available
+                 n = use minor number n
+                You can specify up to 64 cameras this way.
+                For example:
+                video_nr=-1,2,-1 would assign minor number 2 to the second
+                registered camera and use auto for the first one and for every
+                other camera.
+Default:        -1
+-------------------------------------------------------------------------------
+Name:           force_munmap
+Type:           bool array (min = 0, max = 64)
+Syntax:         <0|1[,...]>
+Description:    Force the application to unmap previously mapped buffer memory
+                before calling any VIDIOC_S_CROP or VIDIOC_S_FMT ioctl's. Not
+                all the applications support this feature. This parameter is
+                specific for each detected camera.
+                0 = do not force memory unmapping
+                1 = force memory unmapping (save memory)
+Default:        0
+-------------------------------------------------------------------------------
+Name:           debug
+Type:           ushort
+Syntax:         <n>
+Description:    Debugging information level, from 0 to 3:
+                0 = none (use carefully)
+                1 = critical errors
+                2 = significant informations
+                3 = more verbose messages
+                Level 3 is useful for testing only, when only one device
+                is used at the same time. It also shows some more informations
+                about the hardware being detected. This module parameter can be
+                changed at runtime thanks to the /sys filesystem interface.
+Default:        2
+-------------------------------------------------------------------------------
+
+
+8. Supported devices
+====================
+None of the names of the companies as well as their products will be mentioned
+here. They have never collaborated with the author, so no advertising.
+
+From the point of view of a driver, what unambiguously identify a device are
+its vendor and product USB identifiers. Below is a list of known identifiers of
+devices mounting the ZC0301 Image Processor and Control Chips:
+
+Vendor ID  Product ID
+---------  ----------
+0x046d     0x08ae
+
+The following image sensors are supported:
+
+Model       Manufacturer
+-----       ------------
+PAS202BCB   PixArt Imaging, Inc.
+
+All the available control settings of each image sensor are supported through
+the V4L2 interface.
+
+
+9. Notes for V4L2 application developers
+========================================
+This driver follows the V4L2 API specifications. In particular, it enforces two
+rules:
+
+- exactly one I/O method, either "mmap" or "read", is associated with each
+file descriptor. Once it is selected, the application must close and reopen the
+device to switch to the other I/O method;
+
+- although it is not mandatory, previously mapped buffer memory should always
+be unmapped before calling any "VIDIOC_S_CROP" or "VIDIOC_S_FMT" ioctl's.
+The same number of buffers as before will be allocated again to match the size
+of the new video frames, so you have to map the buffers again before any I/O
+attempts on them.
+
+This driver supports the standard JPEG video format. The current compression
+quality may vary from 0 to 3 and can be selected or queried thanks to the
+VIDIOC_S_JPEGCOMP and VIDIOC_G_JPEGCOMP V4L2 ioctl's.
+
+
+10. Contact information
+=======================
+The author may be contacted by e-mail at <luca.risolia@studio.unibo.it>.
+
+GPG/PGP encrypted e-mail's are accepted. The GPG key ID of the author is
+'FCE635A4'; the public 1024-bit key should be available at any keyserver;
+the fingerprint is: '88E8 F32F 7244 68BA 3958  5D40 99DA 5D2A FCE6 35A4'.
+
+
+11. Credits
+===========
+- Informations about the chip internals to enable the I2C protocol have been
+  taken from the documentation of the ZC030x Video4Linux1 driver written by
+  Andrew Birkett <andy@nobugs.org>;
+- Initialization values of the ZC0301 connected to the PAS202BCB image sensor
+  have been taken from the SPCA5XX driver maintained by
+  Michel Xhaard  <mxhaard@magic.fr>

MAINTAINERS

@@ -2902,6 +2902,14 @@ L:	video4linux-list@redhat.com
 W:	http://www.linux-projects.org
 S:	Maintained
 
+USB ZC0301 DRIVER
+P:	Luca Risolia
+M:	luca.risolia@studio.unibo.it
+L:	linux-usb-devel@lists.sourceforge.net
+L:	video4linux-list@redhat.com
+W:	http://www.linux-projects.org
+S:	Maintained
+
 USB ZD1201 DRIVER
 P:	Jeroen Vreeken
 M:	pe1rxq@amsat.org

drivers/usb/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_USB_SN9C102)	+= media/
 obj-$(CONFIG_USB_STV680)	+= media/
 obj-$(CONFIG_USB_VICAM)		+= media/
 obj-$(CONFIG_USB_W9968CF)	+= media/
+obj-$(CONFIG_USB_ZC0301)	+= media/
 
 obj-$(CONFIG_USB_CATC)		+= net/
 obj-$(CONFIG_USB_KAWETH)	+= net/

drivers/usb/media/Kconfig

@@ -191,6 +191,21 @@ config USB_W9968CF
 	  To compile this driver as a module, choose M here: the
 	  module will be called w9968cf.
 
+config USB_ZC0301
+	tristate "USB ZC0301 Image Processor and Control Chip support"
+	depends on USB && VIDEO_DEV
+	---help---
+	  Say Y here if you want support for cameras based on the ZC0301
+	  Image Processor and Control Chip.
+
+	  See <file:Documentation/usb/zc0301.txt> for more informations.
+
+	  This driver uses the Video For Linux API. You must say Y or M to
+	  "Video For Linux" to use this driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called zc0301.
+
 config USB_PWC
 	tristate "USB Philips Cameras"
 	depends on USB && VIDEO_DEV

drivers/usb/media/Makefile

@@ -4,6 +4,7 @@
 
 sn9c102-objs	:= sn9c102_core.o sn9c102_hv7131d.o sn9c102_mi0343.o sn9c102_ov7630.o sn9c102_pas106b.o sn9c102_pas202bcb.o sn9c102_tas5110c1b.o sn9c102_tas5130d1b.o
 et61x251-objs	:= et61x251_core.o et61x251_tas5130d1b.o
+zc0301-objs	:= zc0301_core.o zc0301_pas202bcb.o
 
 obj-$(CONFIG_USB_DABUSB)	+= dabusb.o
 obj-$(CONFIG_USB_DSBR)		+= dsbr100.o
@@ -16,4 +17,5 @@ obj-$(CONFIG_USB_SN9C102)	+= sn9c102.o
 obj-$(CONFIG_USB_STV680)	+= stv680.o
 obj-$(CONFIG_USB_VICAM)		+= vicam.o usbvideo.o
 obj-$(CONFIG_USB_W9968CF)	+= w9968cf.o
+obj-$(CONFIG_USB_ZC0301)	+= zc0301.o
 obj-$(CONFIG_USB_PWC)           += pwc/

drivers/usb/media/zc0301.h

+/***************************************************************************
+ * V4L2 driver for ZC0301 Image Processor and Control Chip                 *
+ *                                                                         *
+ * Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>       *
+ *                                                                         *
+ * This program is free software; you can redistribute it and/or modify    *
+ * it under the terms of the GNU General Public License as published by    *
+ * the Free Software Foundation; either version 2 of the License, or       *
+ * (at your option) any later version.                                     *
+ *                                                                         *
+ * This program is distributed in the hope that it will be useful,         *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
+ * GNU General Public License for more details.                            *
+ *                                                                         *
+ * You should have received a copy of the GNU General Public License       *
+ * along with this program; if not, write to the Free Software             *
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.               *
+ ***************************************************************************/
+
+#ifndef _ZC0301_H_
+#define _ZC0301_H_
+
+#include <linux/version.h>
+#include <linux/usb.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-common.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/time.h>
+#include <linux/wait.h>
+#include <linux/types.h>
+#include <linux/param.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <asm/semaphore.h>
+
+#include "zc0301_sensor.h"
+
+/*****************************************************************************/
+
+#define ZC0301_DEBUG
+#define ZC0301_DEBUG_LEVEL         2
+#define ZC0301_MAX_DEVICES         64
+#define ZC0301_FORCE_MUNMAP        0
+#define ZC0301_MAX_FRAMES          32
+#define ZC0301_COMPRESSION_QUALITY 2
+#define ZC0301_URBS                2
+#define ZC0301_ISO_PACKETS         7
+#define ZC0301_ALTERNATE_SETTING   7
+#define ZC0301_URB_TIMEOUT         msecs_to_jiffies(2 * ZC0301_ISO_PACKETS)
+#define ZC0301_CTRL_TIMEOUT        100
+#define ZC0301_FRAME_TIMEOUT       2 * 1000 * msecs_to_jiffies(1)
+
+/*****************************************************************************/
+
+ZC0301_ID_TABLE
+ZC0301_SENSOR_TABLE
+
+enum zc0301_frame_state {
+	F_UNUSED,
+	F_QUEUED,
+	F_GRABBING,
+	F_DONE,
+	F_ERROR,
+};
+
+struct zc0301_frame_t {
+	void* bufmem;
+	struct v4l2_buffer buf;
+	enum zc0301_frame_state state;
+	struct list_head frame;
+	unsigned long vma_use_count;
+};
+
+enum zc0301_dev_state {
+	DEV_INITIALIZED = 0x01,
+	DEV_DISCONNECTED = 0x02,
+	DEV_MISCONFIGURED = 0x04,
+};
+
+enum zc0301_io_method {
+	IO_NONE,
+	IO_READ,
+	IO_MMAP,
+};
+
+enum zc0301_stream_state {
+	STREAM_OFF,
+	STREAM_INTERRUPT,
+	STREAM_ON,
+};
+
+struct zc0301_module_param {
+	u8 force_munmap;
+};
+
+static DECLARE_RWSEM(zc0301_disconnect);
+
+struct zc0301_device {
+	struct video_device* v4ldev;
+
+	struct zc0301_sensor* sensor;
+
+	struct usb_device* usbdev;
+	struct urb* urb[ZC0301_URBS];
+	void* transfer_buffer[ZC0301_URBS];
+	u8* control_buffer;
+
+	struct zc0301_frame_t *frame_current, frame[ZC0301_MAX_FRAMES];
+	struct list_head inqueue, outqueue;
+	u32 frame_count, nbuffers, nreadbuffers;
+
+	enum zc0301_io_method io;
+	enum zc0301_stream_state stream;
+
+	struct v4l2_jpegcompression compression;
+
+	struct zc0301_module_param module_param;
+
+	enum zc0301_dev_state state;
+	u8 users;
+
+	struct mutex dev_mutex, fileop_mutex;
+	spinlock_t queue_lock;
+	wait_queue_head_t open, wait_frame, wait_stream;
+};
+
+/*****************************************************************************/
+
+void
+zc0301_attach_sensor(struct zc0301_device* cam, struct zc0301_sensor* sensor)
+{
+	cam->sensor = sensor;
+	cam->sensor->usbdev = cam->usbdev;
+}
+
+/*****************************************************************************/
+
+#undef DBG
+#undef KDBG
+#ifdef ZC0301_DEBUG
+#	define DBG(level, fmt, args...)                                       \
+do {                                                                          \
+	if (debug >= (level)) {                                               \
+		if ((level) == 1)                                             \
+			dev_err(&cam->usbdev->dev, fmt "\n", ## args);        \
+		else if ((level) == 2)                                        \
+			dev_info(&cam->usbdev->dev, fmt "\n", ## args);       \
+		else if ((level) >= 3)                                        \
+			dev_info(&cam->usbdev->dev, "[%s:%d] " fmt "\n",      \
+			         __FUNCTION__, __LINE__ , ## args);           \
+	}                                                                     \
+} while (0)
+#	define KDBG(level, fmt, args...)                                      \
+do {                                                                          \
+	if (debug >= (level)) {                                               \
+		if ((level) == 1 || (level) == 2)                             \
+			pr_info("zc0301: " fmt "\n", ## args);                \
+		else if ((level) == 3)                                        \
+			pr_debug("zc0301: [%s:%d] " fmt "\n", __FUNCTION__,   \
+			         __LINE__ , ## args);                         \
+	}                                                                     \
+} while (0)
+#	define V4LDBG(level, name, cmd)                                       \
+do {                                                                          \
+	if (debug >= (level))                                                 \
+		v4l_print_ioctl(name, cmd);                                   \
+} while (0)
+#else
+#	define DBG(level, fmt, args...) do {;} while(0)
+#	define KDBG(level, fmt, args...) do {;} while(0)
+#	define V4LDBG(level, name, cmd) do {;} while(0)
+#endif
+
+#undef PDBG
+#define PDBG(fmt, args...)                                                    \
+dev_info(&cam->usbdev->dev, "[%s:%d] " fmt "\n",                              \
+         __FUNCTION__, __LINE__ , ## args)
+
+#undef PDBGG
+#define PDBGG(fmt, args...) do {;} while(0) /* placeholder */
+
+#endif /* _ZC0301_H_ */

drivers/usb/media/zc0301_core.c

+/***************************************************************************
+ * Video4Linux2 driver for ZC0301 Image Processor and Control Chip         *
+ *                                                                         *
+ * Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>       *
+ *                                                                         *
+ * Informations about the chip internals to enable the I2C protocol have   *
+ * been taken from the documentation of the ZC030x Video4Linux1 driver     *
+ * written by Andrew Birkett <andy@nobugs.org>                             *
+ *                                                                         *
+ * This program is free software; you can redistribute it and/or modify    *
+ * it under the terms of the GNU General Public License as published by    *
+ * the Free Software Foundation; either version 2 of the License, or       *
+ * (at your option) any later version.                                     *
+ *                                                                         *
+ * This program is distributed in the hope that it will be useful,         *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
+ * GNU General Public License for more details.                            *
+ *                                                                         *
+ * You should have received a copy of the GNU General Public License       *
+ * along with this program; if not, write to the Free Software             *
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.               *
+ ***************************************************************************/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <linux/stddef.h>
+#include <linux/compiler.h>
+#include <linux/ioctl.h>
+#include <linux/poll.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/page-flags.h>
+#include <linux/byteorder/generic.h>
+#include <asm/page.h>
+#include <asm/uaccess.h>
+
+#include "zc0301.h"
+
+/*****************************************************************************/
+
+#define ZC0301_MODULE_NAME    "V4L2 driver for ZC0301 "                       \
+                              "Image Processor and Control Chip"
+#define ZC0301_MODULE_AUTHOR  "(C) 2006 Luca Risolia"
+#define ZC0301_AUTHOR_EMAIL   "<luca.risolia@studio.unibo.it>"
+#define ZC0301_MODULE_LICENSE "GPL"
+#define ZC0301_MODULE_VERSION "1:1.00"
+#define ZC0301_MODULE_VERSION_CODE  KERNEL_VERSION(1, 0, 0)
+
+/*****************************************************************************/
+
+MODULE_DEVICE_TABLE(usb, zc0301_id_table);
+
+MODULE_AUTHOR(ZC0301_MODULE_AUTHOR " " ZC0301_AUTHOR_EMAIL);
+MODULE_DESCRIPTION(ZC0301_MODULE_NAME);
+MODULE_VERSION(ZC0301_MODULE_VERSION);
+MODULE_LICENSE(ZC0301_MODULE_LICENSE);
+
+static short video_nr[] = {[0 ... ZC0301_MAX_DEVICES-1] = -1};
+module_param_array(video_nr, short, NULL, 0444);
+MODULE_PARM_DESC(video_nr,
+                 "\n<-1|n[,...]> Specify V4L2 minor mode number."
+                 "\n -1 = use next available (default)"
+                 "\n  n = use minor number n (integer >= 0)"
+                 "\nYou can specify up to "
+                 __MODULE_STRING(ZC0301_MAX_DEVICES) " cameras this way."
+                 "\nFor example:"
+                 "\nvideo_nr=-1,2,-1 would assign minor number 2 to"
+                 "\nthe second registered camera and use auto for the first"
+                 "\none and for every other camera."
+                 "\n");
+
+static short force_munmap[] = {[0 ... ZC0301_MAX_DEVICES-1] =
+                               ZC0301_FORCE_MUNMAP};
+module_param_array(force_munmap, bool, NULL, 0444);
+MODULE_PARM_DESC(force_munmap,
+                 "\n<0|1[,...]> Force the application to unmap previously"
+                 "\nmapped buffer memory before calling any VIDIOC_S_CROP or"
+                 "\nVIDIOC_S_FMT ioctl's. Not all the applications support"
+                 "\nthis feature. This parameter is specific for each"
+                 "\ndetected camera."
+                 "\n 0 = do not force memory unmapping"
+                 "\n 1 = force memory unmapping (save memory)"
+                 "\nDefault value is "__MODULE_STRING(SN9C102_FORCE_MUNMAP)"."
+                 "\n");
+
+#ifdef ZC0301_DEBUG
+static unsigned short debug = ZC0301_DEBUG_LEVEL;
+module_param(debug, ushort, 0644);
+MODULE_PARM_DESC(debug,
+                 "\n<n> Debugging information level, from 0 to 3:"
+                 "\n0 = none (use carefully)"
+                 "\n1 = critical errors"
+                 "\n2 = significant informations"
+                 "\n3 = more verbose messages"
+                 "\nLevel 3 is useful for testing only, when only "
+                 "one device is used."
+                 "\nDefault value is "__MODULE_STRING(ZC0301_DEBUG_LEVEL)"."
+                 "\n");
+#endif
+
+/*****************************************************************************/
+
+static u32
+zc0301_request_buffers(struct zc0301_device* cam, u32 count,
+                       enum zc0301_io_method io)
+{
+	struct v4l2_pix_format* p = &(cam->sensor->pix_format);
+	struct v4l2_rect* r = &(cam->sensor->cropcap.bounds);
+	const size_t imagesize = cam->module_param.force_munmap ||
+	                         io == IO_READ ?
+	                         (p->width * p->height * p->priv) / 8 :
+	                         (r->width * r->height * p->priv) / 8;
+	void* buff = NULL;
+	u32 i;
+
+	if (count > ZC0301_MAX_FRAMES)
+		count = ZC0301_MAX_FRAMES;
+
+	cam->nbuffers = count;
+	while (cam->nbuffers > 0) {
+		if ((buff = vmalloc_32(cam->nbuffers * PAGE_ALIGN(imagesize))))
+			break;
+		cam->nbuffers--;
+	}
+
+	for (i = 0; i < cam->nbuffers; i++) {
+		cam->frame[i].bufmem = buff + i*PAGE_ALIGN(imagesize);
+		cam->frame[i].buf.index = i;
+		cam->frame[i].buf.m.offset = i*PAGE_ALIGN(imagesize);
+		cam->frame[i].buf.length = imagesize;
+		cam->frame[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		cam->frame[i].buf.sequence = 0;
+		cam->frame[i].buf.field = V4L2_FIELD_NONE;
+		cam->frame[i].buf.memory = V4L2_MEMORY_MMAP;
+		cam->frame[i].buf.flags = 0;
+	}
+
+	return cam->nbuffers;
+}
+
+
+static void zc0301_release_buffers(struct zc0301_device* cam)
+{
+	if (cam->nbuffers) {
+		vfree(cam->frame[0].bufmem);
+		cam->nbuffers = 0;
+	}
+	cam->frame_current = NULL;
+}
+
+
+static void zc0301_empty_framequeues(struct zc0301_device* cam)
+{
+	u32 i;
+
+	INIT_LIST_HEAD(&cam->inqueue);
+	INIT_LIST_HEAD(&cam->outqueue);
+
+	for (i = 0; i < ZC0301_MAX_FRAMES; i++) {
+		cam->frame[i].state = F_UNUSED;
+		cam->frame[i].buf.bytesused = 0;
+	}
+}
+
+
+static void zc0301_requeue_outqueue(struct zc0301_device* cam)
+{
+	struct zc0301_frame_t *i;
+
+	list_for_each_entry(i, &cam->outqueue, frame) {
+		i->state = F_QUEUED;
+		list_add(&i->frame, &cam->inqueue);
+	}
+
+	INIT_LIST_HEAD(&cam->outqueue);
+}
+
+
+static void zc0301_queue_unusedframes(struct zc0301_device* cam)
+{
+	unsigned long lock_flags;
+	u32 i;
+
+	for (i = 0; i < cam->nbuffers; i++)
+		if (cam->frame[i].state == F_UNUSED) {
+			cam->frame[i].state = F_QUEUED;
+			spin_lock_irqsave(&cam->queue_lock, lock_flags);
+			list_add_tail(&cam->frame[i].frame, &cam->inqueue);
+			spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
+		}
+}
+
+/*****************************************************************************/
+
+int zc0301_write_reg(struct zc0301_device* cam, u16 index, u16 value)
+{
+	struct usb_device* udev = cam->usbdev;
+	int res;
+
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0xa0, 0x40,
+	                      value, index, NULL, 0, ZC0301_CTRL_TIMEOUT);
+	if (res < 0) {
+		DBG(3, "Failed to write a register (index 0x%04X, "
+		       "value 0x%02X, error %d)",index, value, res);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int zc0301_read_reg(struct zc0301_device* cam, u16 index)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* buff = cam->control_buffer;
+	int res;
+
+	res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0xa1, 0xc0,
+	                      0x0001, index, buff, 1, ZC0301_CTRL_TIMEOUT);
+	if (res < 0)
+		DBG(3, "Failed to read a register (index 0x%04X, error %d)",
+		    index, res);
+
+	PDBGG("Read: index 0x%04X, value: 0x%04X", index, (int)(*buff));
+
+	return (res >= 0) ? (int)(*buff) : -1;
+}
+
+
+int zc0301_i2c_read(struct zc0301_device* cam, u16 address, u8 length)
+{
+	int err = 0, res, r0, r1;
+
+	err += zc0301_write_reg(cam, 0x0092, address);
+	err += zc0301_write_reg(cam, 0x0090, 0x02);
+
+	msleep(1);
+
+	res = zc0301_read_reg(cam, 0x0091);
+	if (res < 0)
+		err += res;
+	r0 = zc0301_read_reg(cam, 0x0095);
+	if (r0 < 0)
+		err += r0;
+	r1 = zc0301_read_reg(cam, 0x0096);
+	if (r1 < 0)
+		err += r1;
+
+	res = (length <= 1) ? r0 : r0 | (r1 << 8);
+
+	if (err)
+		DBG(3, "I2C read failed at address 0x%04X, value: 0x%04X",
+		    address, res);
+
+
+	PDBGG("I2C read: address 0x%04X, value: 0x%04X", address, res);
+
+	return err ? -1 : res;
+}
+
+
+int zc0301_i2c_write(struct zc0301_device* cam, u16 address, u16 value)
+{
+	int err = 0, res;
+
+	err += zc0301_write_reg(cam, 0x0092, address);
+	err += zc0301_write_reg(cam, 0x0093, value & 0xff);
+	err += zc0301_write_reg(cam, 0x0094, value >> 8);
+	err += zc0301_write_reg(cam, 0x0090, 0x01);
+
+	msleep(1);
+
+	res = zc0301_read_reg(cam, 0x0091);
+	if (res < 0)
+		err += res;
+
+	if (err)
+		DBG(3, "I2C write failed at address 0x%04X, value: 0x%04X",
+		    address, value);
+
+	PDBGG("I2C write: address 0x%04X, value: 0x%04X", address, value);
+
+	return err ? -1 : 0;
+}
+
+/*****************************************************************************/
+
+static void zc0301_urb_complete(struct urb *urb, struct pt_regs* regs)
+{
+	struct zc0301_device* cam = urb->context;
+	struct zc0301_frame_t** f;
+	size_t imagesize;
+	u8 i;
+	int err = 0;
+
+	if (urb->status == -ENOENT)
+		return;
+
+	f = &cam->frame_current;
+
+	if (cam->stream == STREAM_INTERRUPT) {
+		cam->stream = STREAM_OFF;
+		if ((*f))
+			(*f)->state = F_QUEUED;
+		DBG(3, "Stream interrupted");
+		wake_up_interruptible(&cam->wait_stream);
+	}
+
+	if (cam->state & DEV_DISCONNECTED)
+		return;
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		wake_up_interruptible(&cam->wait_frame);
+		return;
+	}
+
+	if (cam->stream == STREAM_OFF || list_empty(&cam->inqueue))
+		goto resubmit_urb;
+
+	if (!(*f))
+		(*f) = list_entry(cam->inqueue.next, struct zc0301_frame_t,
+		                  frame);
+
+	imagesize = (cam->sensor->pix_format.width *
+	             cam->sensor->pix_format.height *
+	             cam->sensor->pix_format.priv) / 8;
+
+	for (i = 0; i < urb->number_of_packets; i++) {
+		unsigned int len, status;
+		void *pos;
+		u16* soi;
+		u8 sof;
+
+		len = urb->iso_frame_desc[i].actual_length;
+		status = urb->iso_frame_desc[i].status;
+		pos = urb->iso_frame_desc[i].offset + urb->transfer_buffer;
+
+		if (status) {
+			DBG(3, "Error in isochronous frame");
+			(*f)->state = F_ERROR;
+			continue;
+		}
+
+		sof = (*(soi = pos) == 0xd8ff);
+
+		PDBGG("Isochrnous frame: length %u, #%u i,", len, i);
+
+		if ((*f)->state == F_QUEUED || (*f)->state == F_ERROR)
+start_of_frame:
+			if (sof) {
+				(*f)->state = F_GRABBING;
+				(*f)->buf.bytesused = 0;
+				do_gettimeofday(&(*f)->buf.timestamp);
+				DBG(3, "SOF detected: new video frame");
+			}
+
+		if ((*f)->state == F_GRABBING) {
+			if (sof && (*f)->buf.bytesused)
+					goto end_of_frame;
+
+			if ((*f)->buf.bytesused + len > imagesize) {
+				DBG(3, "Video frame size exceeded");
+				(*f)->state = F_ERROR;
+				continue;
+			}
+
+			memcpy((*f)->bufmem+(*f)->buf.bytesused, pos, len);
+			(*f)->buf.bytesused += len;
+
+			if ((*f)->buf.bytesused == imagesize) {
+				u32 b;
+end_of_frame:
+				b = (*f)->buf.bytesused;
+				(*f)->state = F_DONE;
+				(*f)->buf.sequence= ++cam->frame_count;
+				spin_lock(&cam->queue_lock);
+				list_move_tail(&(*f)->frame, &cam->outqueue);
+				if (!list_empty(&cam->inqueue))
+					(*f) = list_entry(cam->inqueue.next,
+					               struct zc0301_frame_t,
+					                  frame);
+				else
+					(*f) = NULL;
+				spin_unlock(&cam->queue_lock);
+				DBG(3, "Video frame captured: : %lu bytes",
+				       (unsigned long)(b));
+
+				if (!(*f))
+					goto resubmit_urb;
+
+				if (sof)
+					goto start_of_frame;
+			}
+		}
+	}
+
+resubmit_urb:
+	urb->dev = cam->usbdev;
+	err = usb_submit_urb(urb, GFP_ATOMIC);
+	if (err < 0 && err != -EPERM) {
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "usb_submit_urb() failed");
+	}
+
+	wake_up_interruptible(&cam->wait_frame);
+}
+
+
+static int zc0301_start_transfer(struct zc0301_device* cam)
+{
+	struct usb_device *udev = cam->usbdev;
+	struct urb* urb;
+	const unsigned int wMaxPacketSize[] = {0, 128, 192, 256, 384,
+	                                       512, 768, 1023};
+	const unsigned int psz = wMaxPacketSize[ZC0301_ALTERNATE_SETTING];
+	s8 i, j;
+	int err = 0;
+
+	for (i = 0; i < ZC0301_URBS; i++) {
+		cam->transfer_buffer[i] = kzalloc(ZC0301_ISO_PACKETS * psz,
+		                                  GFP_KERNEL);
+		if (!cam->transfer_buffer[i]) {
+			err = -ENOMEM;
+			DBG(1, "Not enough memory");
+			goto free_buffers;
+		}
+	}
+
+	for (i = 0; i < ZC0301_URBS; i++) {
+		urb = usb_alloc_urb(ZC0301_ISO_PACKETS, GFP_KERNEL);
+		cam->urb[i] = urb;
+		if (!urb) {
+			err = -ENOMEM;
+			DBG(1, "usb_alloc_urb() failed");
+			goto free_urbs;
+		}
+		urb->dev = udev;
+		urb->context = cam;
+		urb->pipe = usb_rcvisocpipe(udev, 1);
+		urb->transfer_flags = URB_ISO_ASAP;
+		urb->number_of_packets = ZC0301_ISO_PACKETS;
+		urb->complete = zc0301_urb_complete;
+		urb->transfer_buffer = cam->transfer_buffer[i];
+		urb->transfer_buffer_length = psz * ZC0301_ISO_PACKETS;
+		urb->interval = 1;
+		for (j = 0; j < ZC0301_ISO_PACKETS; j++) {
+			urb->iso_frame_desc[j].offset = psz * j;
+			urb->iso_frame_desc[j].length = psz;
+		}
+	}
+
+	err = usb_set_interface(udev, 0, ZC0301_ALTERNATE_SETTING);
+	if (err) {
+		DBG(1, "usb_set_interface() failed");
+		goto free_urbs;
+	}
+
+	cam->frame_current = NULL;
+
+	for (i = 0; i < ZC0301_URBS; i++) {
+		err = usb_submit_urb(cam->urb[i], GFP_KERNEL);
+		if (err) {
+			for (j = i-1; j >= 0; j--)
+				usb_kill_urb(cam->urb[j]);
+			DBG(1, "usb_submit_urb() failed, error %d", err);
+			goto free_urbs;
+		}
+	}
+
+	return 0;
+
+free_urbs:
+	for (i = 0; (i < ZC0301_URBS) &&  cam->urb[i]; i++)
+		usb_free_urb(cam->urb[i]);
+
+free_buffers:
+	for (i = 0; (i < ZC0301_URBS) && cam->transfer_buffer[i]; i++)
+		kfree(cam->transfer_buffer[i]);
+
+	return err;
+}
+
+
+static int zc0301_stop_transfer(struct zc0301_device* cam)
+{
+	struct usb_device *udev = cam->usbdev;
+	s8 i;
+	int err = 0;
+
+	if (cam->state & DEV_DISCONNECTED)
+		return 0;
+
+	for (i = ZC0301_URBS-1; i >= 0; i--) {
+		usb_kill_urb(cam->urb[i]);
+		usb_free_urb(cam->urb[i]);
+		kfree(cam->transfer_buffer[i]);
+	}
+
+	err = usb_set_interface(udev, 0, 0); /* 0 Mb/s */
+	if (err)
+		DBG(3, "usb_set_interface() failed");
+
+	return err;
+}
+
+
+static int zc0301_stream_interrupt(struct zc0301_device* cam)
+{
+	long timeout;
+
+	cam->stream = STREAM_INTERRUPT;
+	timeout = wait_event_timeout(cam->wait_stream,
+	                             (cam->stream == STREAM_OFF) ||
+	                             (cam->state & DEV_DISCONNECTED),
+	                             ZC0301_URB_TIMEOUT);
+	if (cam->state & DEV_DISCONNECTED)
+		return -ENODEV;
+	else if (!timeout) {
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "URB timeout reached. The camera is misconfigured. To "
+		       "use it, close and open /dev/video%d again.",
+		    cam->v4ldev->minor);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+
+static int
+zc0301_set_compression(struct zc0301_device* cam,
+                       struct v4l2_jpegcompression* compression)
+{
+	int r, err = 0;
+
+	if ((r = zc0301_read_reg(cam, 0x0008)) < 0)
+		err += r;
+	err += zc0301_write_reg(cam, 0x0008,
+	                        r | 0x11 | (compression->quality >> 1));
+
+	return err ? -EIO : 0;
+}
+
+
+static int zc0301_init(struct zc0301_device* cam)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_control ctrl;
+	struct v4l2_queryctrl *qctrl;
+	struct v4l2_rect* rect;
+	u8 i = 0;
+	int err = 0;
+
+	if (!(cam->state & DEV_INITIALIZED)) {
+		init_waitqueue_head(&cam->open);
+		qctrl = s->qctrl;
+		rect = &(s->cropcap.defrect);
+		cam->compression.quality = ZC0301_COMPRESSION_QUALITY;
+	} else { /* use current values */
+		qctrl = s->_qctrl;
+		rect = &(s->_rect);
+	}
+
+	if (s->init) {
+		err = s->init(cam);
+		if (err) {
+			DBG(3, "Sensor initialization failed");
+			return err;
+		}
+	}
+
+	if ((err = zc0301_set_compression(cam, &cam->compression))) {
+		DBG(3, "set_compression() failed");
+		return err;
+	}
+
+	if (s->set_crop)
+		if ((err = s->set_crop(cam, rect))) {
+			DBG(3, "set_crop() failed");
+			return err;
+		}
+
+	if (s->set_ctrl) {
+		for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
+			if (s->qctrl[i].id != 0 &&
+			    !(s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)) {
+				ctrl.id = s->qctrl[i].id;
+				ctrl.value = qctrl[i].default_value;
+				err = s->set_ctrl(cam, &ctrl);
+				if (err) {
+					DBG(3, "Set %s control failed",
+					    s->qctrl[i].name);
+					return err;
+				}
+				DBG(3, "Image sensor supports '%s' control",
+				    s->qctrl[i].name);
+			}
+	}
+
+	if (!(cam->state & DEV_INITIALIZED)) {
+		mutex_init(&cam->fileop_mutex);
+		spin_lock_init(&cam->queue_lock);
+		init_waitqueue_head(&cam->wait_frame);
+		init_waitqueue_head(&cam->wait_stream);
+		cam->nreadbuffers = 2;
+		memcpy(s->_qctrl, s->qctrl, sizeof(s->qctrl));
+		memcpy(&(s->_rect), &(s->cropcap.defrect),
+		       sizeof(struct v4l2_rect));
+		cam->state |= DEV_INITIALIZED;
+	}
+
+	DBG(2, "Initialization succeeded");
+	return 0;
+}
+
+
+static void zc0301_release_resources(struct zc0301_device* cam)
+{
+	DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
+	video_set_drvdata(cam->v4ldev, NULL);
+	video_unregister_device(cam->v4ldev);
+	kfree(cam->control_buffer);
+}
+
+/*****************************************************************************/
+
+static int zc0301_open(struct inode* inode, struct file* filp)
+{
+	struct zc0301_device* cam;
+	int err = 0;
+
+	/*
+	   This is the only safe way to prevent race conditions with
+	   disconnect
+	*/
+	if (!down_read_trylock(&zc0301_disconnect))
+		return -ERESTARTSYS;
+
+	cam = video_get_drvdata(video_devdata(filp));
+
+	if (mutex_lock_interruptible(&cam->dev_mutex)) {
+		up_read(&zc0301_disconnect);
+		return -ERESTARTSYS;
+	}
+
+	if (cam->users) {
+		DBG(2, "Device /dev/video%d is busy...", cam->v4ldev->minor);
+		if ((filp->f_flags & O_NONBLOCK) ||
+		    (filp->f_flags & O_NDELAY)) {
+			err = -EWOULDBLOCK;
+			goto out;
+		}
+		mutex_unlock(&cam->dev_mutex);
+		err = wait_event_interruptible_exclusive(cam->open,
+		                                  cam->state & DEV_DISCONNECTED
+		                                         || !cam->users);
+		if (err) {
+			up_read(&zc0301_disconnect);
+			return err;
+		}
+		if (cam->state & DEV_DISCONNECTED) {
+			up_read(&zc0301_disconnect);
+			return -ENODEV;
+		}
+		mutex_lock(&cam->dev_mutex);
+	}
+
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		err = zc0301_init(cam);
+		if (err) {
+			DBG(1, "Initialization failed again. "
+			       "I will retry on next open().");
+			goto out;
+		}
+		cam->state &= ~DEV_MISCONFIGURED;
+	}
+
+	if ((err = zc0301_start_transfer(cam)))
+		goto out;
+
+	filp->private_data = cam;
+	cam->users++;
+	cam->io = IO_NONE;
+	cam->stream = STREAM_OFF;
+	cam->nbuffers = 0;
+	cam->frame_count = 0;
+	zc0301_empty_framequeues(cam);
+
+	DBG(3, "Video device /dev/video%d is open", cam->v4ldev->minor);
+
+out:
+	mutex_unlock(&cam->dev_mutex);
+	up_read(&zc0301_disconnect);
+	return err;
+}
+
+
+static int zc0301_release(struct inode* inode, struct file* filp)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+
+	mutex_lock(&cam->dev_mutex); /* prevent disconnect() to be called */
+
+	zc0301_stop_transfer(cam);
+
+	zc0301_release_buffers(cam);
+
+	if (cam->state & DEV_DISCONNECTED) {
+		zc0301_release_resources(cam);
+		mutex_unlock(&cam->dev_mutex);
+		kfree(cam);
+		return 0;
+	}
+
+	cam->users--;
+	wake_up_interruptible_nr(&cam->open, 1);
+
+	DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);
+
+	mutex_unlock(&cam->dev_mutex);
+
+	return 0;
+}
+
+
+static ssize_t
+zc0301_read(struct file* filp, char __user * buf,
+              size_t count, loff_t* f_pos)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+	struct zc0301_frame_t* f, * i;
+	unsigned long lock_flags;
+	long timeout;
+	int err = 0;
+
+	if (mutex_lock_interruptible(&cam->fileop_mutex))
+		return -ERESTARTSYS;
+
+	if (cam->state & DEV_DISCONNECTED) {
+		DBG(1, "Device not present");
+		mutex_unlock(&cam->fileop_mutex);
+		return -ENODEV;
+	}
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		DBG(1, "The camera is misconfigured. Close and open it "
+		       "again.");
+		mutex_unlock(&cam->fileop_mutex);
+		return -EIO;
+	}
+
+	if (cam->io == IO_MMAP) {
+		DBG(3, "Close and open the device again to choose the read "
+		       "method");
+		mutex_unlock(&cam->fileop_mutex);
+		return -EINVAL;
+	}
+
+	if (cam->io == IO_NONE) {
+		if (!zc0301_request_buffers(cam, cam->nreadbuffers, IO_READ)) {
+			DBG(1, "read() failed, not enough memory");
+			mutex_unlock(&cam->fileop_mutex);
+			return -ENOMEM;
+		}
+		cam->io = IO_READ;
+		cam->stream = STREAM_ON;
+	}
+
+	if (list_empty(&cam->inqueue)) {
+		if (!list_empty(&cam->outqueue))
+			zc0301_empty_framequeues(cam);
+		zc0301_queue_unusedframes(cam);
+	}
+
+	if (!count) {
+		mutex_unlock(&cam->fileop_mutex);
+		return 0;
+	}
+
+	if (list_empty(&cam->outqueue)) {
+		if (filp->f_flags & O_NONBLOCK) {
+			mutex_unlock(&cam->fileop_mutex);
+			return -EAGAIN;
+		}
+		timeout = wait_event_interruptible_timeout
+		          ( cam->wait_frame,
+		            (!list_empty(&cam->outqueue)) ||
+		            (cam->state & DEV_DISCONNECTED) ||
+		            (cam->state & DEV_MISCONFIGURED),
+		            ZC0301_FRAME_TIMEOUT );
+		if (timeout < 0) {
+			mutex_unlock(&cam->fileop_mutex);
+			return timeout;
+		}
+		if (cam->state & DEV_DISCONNECTED) {
+			mutex_unlock(&cam->fileop_mutex);
+			return -ENODEV;
+		}
+		if (!timeout || (cam->state & DEV_MISCONFIGURED)) {
+			mutex_unlock(&cam->fileop_mutex);
+			return -EIO;
+		}
+	}
+
+	f = list_entry(cam->outqueue.prev, struct zc0301_frame_t, frame);
+
+	if (count > f->buf.bytesused)
+		count = f->buf.bytesused;
+
+	if (copy_to_user(buf, f->bufmem, count)) {
+		err = -EFAULT;
+		goto exit;
+	}
+	*f_pos += count;
+
+exit:
+	spin_lock_irqsave(&cam->queue_lock, lock_flags);
+	list_for_each_entry(i, &cam->outqueue, frame)
+		i->state = F_UNUSED;
+	INIT_LIST_HEAD(&cam->outqueue);
+	spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
+
+	zc0301_queue_unusedframes(cam);
+
+	PDBGG("Frame #%lu, bytes read: %zu",
+	      (unsigned long)f->buf.index, count);
+
+	mutex_unlock(&cam->fileop_mutex);
+
+	return err ? err : count;
+}
+
+
+static unsigned int zc0301_poll(struct file *filp, poll_table *wait)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+	struct zc0301_frame_t* f;
+	unsigned long lock_flags;
+	unsigned int mask = 0;
+
+	if (mutex_lock_interruptible(&cam->fileop_mutex))
+		return POLLERR;
+
+	if (cam->state & DEV_DISCONNECTED) {
+		DBG(1, "Device not present");
+		goto error;
+	}
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		DBG(1, "The camera is misconfigured. Close and open it "
+		       "again.");
+		goto error;
+	}
+
+	if (cam->io == IO_NONE) {
+		if (!zc0301_request_buffers(cam, cam->nreadbuffers, IO_READ)) {
+			DBG(1, "poll() failed, not enough memory");
+			goto error;
+		}
+		cam->io = IO_READ;
+		cam->stream = STREAM_ON;
+	}
+
+	if (cam->io == IO_READ) {
+		spin_lock_irqsave(&cam->queue_lock, lock_flags);
+		list_for_each_entry(f, &cam->outqueue, frame)
+			f->state = F_UNUSED;
+		INIT_LIST_HEAD(&cam->outqueue);
+		spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
+		zc0301_queue_unusedframes(cam);
+	}
+
+	poll_wait(filp, &cam->wait_frame, wait);
+
+	if (!list_empty(&cam->outqueue))
+		mask |= POLLIN | POLLRDNORM;
+
+	mutex_unlock(&cam->fileop_mutex);
+
+	return mask;
+
+error:
+	mutex_unlock(&cam->fileop_mutex);
+	return POLLERR;
+}
+
+
+static void zc0301_vm_open(struct vm_area_struct* vma)
+{
+	struct zc0301_frame_t* f = vma->vm_private_data;
+	f->vma_use_count++;
+}
+
+
+static void zc0301_vm_close(struct vm_area_struct* vma)
+{
+	/* NOTE: buffers are not freed here */
+	struct zc0301_frame_t* f = vma->vm_private_data;
+	f->vma_use_count--;
+}
+
+
+static struct vm_operations_struct zc0301_vm_ops = {
+	.open = zc0301_vm_open,
+	.close = zc0301_vm_close,
+};
+
+
+static int zc0301_mmap(struct file* filp, struct vm_area_struct *vma)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+	unsigned long size = vma->vm_end - vma->vm_start,
+	              start = vma->vm_start;
+	void *pos;
+	u32 i;
+
+	if (mutex_lock_interruptible(&cam->fileop_mutex))
+		return -ERESTARTSYS;
+
+	if (cam->state & DEV_DISCONNECTED) {
+		DBG(1, "Device not present");
+		mutex_unlock(&cam->fileop_mutex);
+		return -ENODEV;
+	}
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		DBG(1, "The camera is misconfigured. Close and open it "
+		       "again.");
+		mutex_unlock(&cam->fileop_mutex);
+		return -EIO;
+	}
+
+	if (cam->io != IO_MMAP || !(vma->vm_flags & VM_WRITE) ||
+	    size != PAGE_ALIGN(cam->frame[0].buf.length)) {
+		mutex_unlock(&cam->fileop_mutex);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < cam->nbuffers; i++) {
+		if ((cam->frame[i].buf.m.offset>>PAGE_SHIFT) == vma->vm_pgoff)
+			break;
+	}
+	if (i == cam->nbuffers) {
+		mutex_unlock(&cam->fileop_mutex);
+		return -EINVAL;
+	}
+
+	vma->vm_flags |= VM_IO;
+	vma->vm_flags |= VM_RESERVED;
+
+	pos = cam->frame[i].bufmem;
+	while (size > 0) { /* size is page-aligned */
+		if (vm_insert_page(vma, start, vmalloc_to_page(pos))) {
+			mutex_unlock(&cam->fileop_mutex);
+			return -EAGAIN;
+		}
+		start += PAGE_SIZE;
+		pos += PAGE_SIZE;
+		size -= PAGE_SIZE;
+	}
+
+	vma->vm_ops = &zc0301_vm_ops;
+	vma->vm_private_data = &cam->frame[i];
+
+	zc0301_vm_open(vma);
+
+	mutex_unlock(&cam->fileop_mutex);
+
+	return 0;
+}
+
+/*****************************************************************************/
+
+static int
+zc0301_vidioc_querycap(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_capability cap = {
+		.driver = "zc0301",
+		.version = ZC0301_MODULE_VERSION_CODE,
+		.capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
+		                V4L2_CAP_STREAMING,
+	};
+
+	strlcpy(cap.card, cam->v4ldev->name, sizeof(cap.card));
+	if (usb_make_path(cam->usbdev, cap.bus_info, sizeof(cap.bus_info)) < 0)
+		strlcpy(cap.bus_info, cam->usbdev->dev.bus_id,
+		        sizeof(cap.bus_info));
+
+	if (copy_to_user(arg, &cap, sizeof(cap)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_enuminput(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_input i;
+
+	if (copy_from_user(&i, arg, sizeof(i)))
+		return -EFAULT;
+
+	if (i.index)
+		return -EINVAL;
+
+	memset(&i, 0, sizeof(i));
+	strcpy(i.name, "Camera");
+
+	if (copy_to_user(arg, &i, sizeof(i)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_gs_input(struct zc0301_device* cam, void __user * arg)
+{
+	int index;
+
+	if (copy_from_user(&index, arg, sizeof(index)))
+		return -EFAULT;
+
+	if (index != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_query_ctrl(struct zc0301_device* cam, void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_queryctrl qc;
+	u8 i;
+
+	if (copy_from_user(&qc, arg, sizeof(qc)))
+		return -EFAULT;
+
+	for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
+		if (qc.id && qc.id == s->qctrl[i].id) {
+			memcpy(&qc, &(s->qctrl[i]), sizeof(qc));
+			if (copy_to_user(arg, &qc, sizeof(qc)))
+				return -EFAULT;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+
+static int
+zc0301_vidioc_g_ctrl(struct zc0301_device* cam, void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_control ctrl;
+	int err = 0;
+	u8 i;
+
+	if (!s->get_ctrl && !s->set_ctrl)
+		return -EINVAL;
+
+	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
+		return -EFAULT;
+
+	if (!s->get_ctrl) {
+		for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
+			if (ctrl.id == s->qctrl[i].id) {
+				ctrl.value = s->_qctrl[i].default_value;
+				goto exit;
+			}
+		return -EINVAL;
+	} else
+		err = s->get_ctrl(cam, &ctrl);
+
+exit:
+	if (copy_to_user(arg, &ctrl, sizeof(ctrl)))
+		return -EFAULT;
+
+	return err;
+}
+
+
+static int
+zc0301_vidioc_s_ctrl(struct zc0301_device* cam, void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_control ctrl;
+	u8 i;
+	int err = 0;
+
+	if (!s->set_ctrl)
+		return -EINVAL;
+
+	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
+		return -EFAULT;
+
+	for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
+		if (ctrl.id == s->qctrl[i].id) {
+			if (ctrl.value < s->qctrl[i].minimum ||
+			    ctrl.value > s->qctrl[i].maximum)
+				return -ERANGE;
+			ctrl.value -= ctrl.value % s->qctrl[i].step;
+			break;
+		}
+
+	if ((err = s->set_ctrl(cam, &ctrl)))
+		return err;
+
+	s->_qctrl[i].default_value = ctrl.value;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_cropcap(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_cropcap* cc = &(cam->sensor->cropcap);
+
+	cc->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	cc->pixelaspect.numerator = 1;
+	cc->pixelaspect.denominator = 1;
+
+	if (copy_to_user(arg, cc, sizeof(*cc)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_g_crop(struct zc0301_device* cam, void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_crop crop = {
+		.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+	};
+
+	memcpy(&(crop.c), &(s->_rect), sizeof(struct v4l2_rect));
+
+	if (copy_to_user(arg, &crop, sizeof(crop)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_s_crop(struct zc0301_device* cam, void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_crop crop;
+	struct v4l2_rect* rect;
+	struct v4l2_rect* bounds = &(s->cropcap.bounds);
+	const enum zc0301_stream_state stream = cam->stream;
+	const u32 nbuffers = cam->nbuffers;
+	u32 i;
+	int err = 0;
+
+	if (copy_from_user(&crop, arg, sizeof(crop)))
+		return -EFAULT;
+
+	rect = &(crop.c);
+
+	if (crop.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	if (cam->module_param.force_munmap)
+		for (i = 0; i < cam->nbuffers; i++)
+			if (cam->frame[i].vma_use_count) {
+				DBG(3, "VIDIOC_S_CROP failed. "
+				       "Unmap the buffers first.");
+				return -EINVAL;
+			}
+
+	if (!s->set_crop) {
+		memcpy(rect, &(s->_rect), sizeof(*rect));
+		if (copy_to_user(arg, &crop, sizeof(crop)))
+			return -EFAULT;
+		return 0;
+	}
+
+	rect->left &= ~7L;
+	rect->top &= ~7L;
+	if (rect->width < 8)
+		rect->width = 8;
+	if (rect->height < 8)
+		rect->height = 8;
+	if (rect->width > bounds->width)
+		rect->width = bounds->width;
+	if (rect->height > bounds->height)
+		rect->height = bounds->height;
+	if (rect->left < bounds->left)
+		rect->left = bounds->left;
+	if (rect->top < bounds->top)
+		rect->top = bounds->top;
+	if (rect->left + rect->width > bounds->left + bounds->width)
+		rect->left = bounds->left+bounds->width - rect->width;
+	if (rect->top + rect->height > bounds->top + bounds->height)
+		rect->top = bounds->top+bounds->height - rect->height;
+	rect->width &= ~7L;
+	rect->height &= ~7L;
+
+	if (cam->stream == STREAM_ON)
+		if ((err = zc0301_stream_interrupt(cam)))
+			return err;
+
+	if (copy_to_user(arg, &crop, sizeof(crop))) {
+		cam->stream = stream;
+		return -EFAULT;
+	}
+
+	if (cam->module_param.force_munmap || cam->io == IO_READ)
+		zc0301_release_buffers(cam);
+
+	if (s->set_crop)
+		err += s->set_crop(cam, rect);
+
+	if (err) { /* atomic, no rollback in ioctl() */
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "VIDIOC_S_CROP failed because of hardware problems. To "
+		       "use the camera, close and open /dev/video%d again.",
+		    cam->v4ldev->minor);
+		return -EIO;
+	}
+
+	s->pix_format.width = rect->width;
+	s->pix_format.height = rect->height;
+	memcpy(&(s->_rect), rect, sizeof(*rect));
+
+	if ((cam->module_param.force_munmap  || cam->io == IO_READ) &&
+	    nbuffers != zc0301_request_buffers(cam, nbuffers, cam->io)) {
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "VIDIOC_S_CROP failed because of not enough memory. To "
+		       "use the camera, close and open /dev/video%d again.",
+		    cam->v4ldev->minor);
+		return -ENOMEM;
+	}
+
+	if (cam->io == IO_READ)
+		zc0301_empty_framequeues(cam);
+	else if (cam->module_param.force_munmap)
+		zc0301_requeue_outqueue(cam);
+
+	cam->stream = stream;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_enum_fmt(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_fmtdesc fmtd;
+
+	if (copy_from_user(&fmtd, arg, sizeof(fmtd)))
+		return -EFAULT;
+
+	if (fmtd.index == 0) {
+		strcpy(fmtd.description, "JPEG");
+		fmtd.pixelformat = V4L2_PIX_FMT_JPEG;
+		fmtd.flags = V4L2_FMT_FLAG_COMPRESSED;
+	} else
+		return -EINVAL;
+
+	fmtd.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	memset(&fmtd.reserved, 0, sizeof(fmtd.reserved));
+
+	if (copy_to_user(arg, &fmtd, sizeof(fmtd)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_g_fmt(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_format format;
+	struct v4l2_pix_format* pfmt = &(cam->sensor->pix_format);
+
+	if (copy_from_user(&format, arg, sizeof(format)))
+		return -EFAULT;
+
+	if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	pfmt->bytesperline = 0;
+	pfmt->sizeimage = pfmt->height * ((pfmt->width*pfmt->priv)/8);
+	pfmt->field = V4L2_FIELD_NONE;
+	memcpy(&(format.fmt.pix), pfmt, sizeof(*pfmt));
+
+	if (copy_to_user(arg, &format, sizeof(format)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_try_s_fmt(struct zc0301_device* cam, unsigned int cmd,
+                        void __user * arg)
+{
+	struct zc0301_sensor* s = cam->sensor;
+	struct v4l2_format format;
+	struct v4l2_pix_format* pix;
+	struct v4l2_pix_format* pfmt = &(s->pix_format);
+	struct v4l2_rect* bounds = &(s->cropcap.bounds);
+	struct v4l2_rect rect;
+	const enum zc0301_stream_state stream = cam->stream;
+	const u32 nbuffers = cam->nbuffers;
+	u32 i;
+	int err = 0;
+
+	if (copy_from_user(&format, arg, sizeof(format)))
+		return -EFAULT;
+
+	pix = &(format.fmt.pix);
+
+	if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	memcpy(&rect, &(s->_rect), sizeof(rect));
+
+	if (!s->set_crop) {
+		pix->width = rect.width;
+		pix->height = rect.height;
+	} else {
+		rect.width = pix->width;
+		rect.height = pix->height;
+	}
+
+	if (rect.width < 8)
+		rect.width = 8;
+	if (rect.height < 8)
+		rect.height = 8;
+	if (rect.width > bounds->left + bounds->width - rect.left)
+		rect.width = bounds->left + bounds->width - rect.left;
+	if (rect.height > bounds->top + bounds->height - rect.top)
+		rect.height = bounds->top + bounds->height - rect.top;
+	rect.width &= ~7L;
+	rect.height &= ~7L;
+
+	pix->width = rect.width;
+	pix->height = rect.height;
+	pix->pixelformat = pfmt->pixelformat;
+	pix->priv = pfmt->priv;
+	pix->colorspace = pfmt->colorspace;
+	pix->bytesperline = 0;
+	pix->sizeimage = pix->height * ((pix->width * pix->priv) / 8);
+	pix->field = V4L2_FIELD_NONE;
+
+	if (cmd == VIDIOC_TRY_FMT) {
+		if (copy_to_user(arg, &format, sizeof(format)))
+			return -EFAULT;
+		return 0;
+	}
+
+	if (cam->module_param.force_munmap)
+		for (i = 0; i < cam->nbuffers; i++)
+			if (cam->frame[i].vma_use_count) {
+				DBG(3, "VIDIOC_S_FMT failed. "
+				       "Unmap the buffers first.");
+				return -EINVAL;
+			}
+
+	if (cam->stream == STREAM_ON)
+		if ((err = zc0301_stream_interrupt(cam)))
+			return err;
+
+	if (copy_to_user(arg, &format, sizeof(format))) {
+		cam->stream = stream;
+		return -EFAULT;
+	}
+
+	if (cam->module_param.force_munmap || cam->io == IO_READ)
+		zc0301_release_buffers(cam);
+
+	if (s->set_crop)
+		err += s->set_crop(cam, &rect);
+
+	if (err) { /* atomic, no rollback in ioctl() */
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "VIDIOC_S_FMT failed because of hardware problems. To "
+		       "use the camera, close and open /dev/video%d again.",
+		    cam->v4ldev->minor);
+		return -EIO;
+	}
+
+	memcpy(pfmt, pix, sizeof(*pix));
+	memcpy(&(s->_rect), &rect, sizeof(rect));
+
+	if ((cam->module_param.force_munmap  || cam->io == IO_READ) &&
+	    nbuffers != zc0301_request_buffers(cam, nbuffers, cam->io)) {
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "VIDIOC_S_FMT failed because of not enough memory. To "
+		       "use the camera, close and open /dev/video%d again.",
+		    cam->v4ldev->minor);
+		return -ENOMEM;
+	}
+
+	if (cam->io == IO_READ)
+		zc0301_empty_framequeues(cam);
+	else if (cam->module_param.force_munmap)
+		zc0301_requeue_outqueue(cam);
+
+	cam->stream = stream;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_g_jpegcomp(struct zc0301_device* cam, void __user * arg)
+{
+	if (copy_to_user(arg, &cam->compression, sizeof(cam->compression)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_s_jpegcomp(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_jpegcompression jc;
+	const enum zc0301_stream_state stream = cam->stream;
+	int err = 0;
+
+	if (copy_from_user(&jc, arg, sizeof(jc)))
+		return -EFAULT;
+
+	if (jc.quality < 0 || jc.quality > 3)
+		return -EINVAL;
+
+	if (cam->stream == STREAM_ON)
+		if ((err = zc0301_stream_interrupt(cam)))
+			return err;
+
+	err += zc0301_set_compression(cam, &jc);
+	if (err) { /* atomic, no rollback in ioctl() */
+		cam->state |= DEV_MISCONFIGURED;
+		DBG(1, "VIDIOC_S_JPEGCOMP failed because of hardware "
+		       "problems. To use the camera, close and open "
+		       "/dev/video%d again.", cam->v4ldev->minor);
+		return -EIO;
+	}
+
+	cam->compression.quality = jc.quality;
+
+	cam->stream = stream;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_reqbufs(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_requestbuffers rb;
+	u32 i;
+	int err;
+
+	if (copy_from_user(&rb, arg, sizeof(rb)))
+		return -EFAULT;
+
+	if (rb.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
+	    rb.memory != V4L2_MEMORY_MMAP)
+		return -EINVAL;
+
+	if (cam->io == IO_READ) {
+		DBG(3, "Close and open the device again to choose the mmap "
+		       "I/O method");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < cam->nbuffers; i++)
+		if (cam->frame[i].vma_use_count) {
+			DBG(3, "VIDIOC_REQBUFS failed. "
+			       "Previous buffers are still mapped.");
+			return -EINVAL;
+		}
+
+	if (cam->stream == STREAM_ON)
+		if ((err = zc0301_stream_interrupt(cam)))
+			return err;
+
+	zc0301_empty_framequeues(cam);
+
+	zc0301_release_buffers(cam);
+	if (rb.count)
+		rb.count = zc0301_request_buffers(cam, rb.count, IO_MMAP);
+
+	if (copy_to_user(arg, &rb, sizeof(rb))) {
+		zc0301_release_buffers(cam);
+		cam->io = IO_NONE;
+		return -EFAULT;
+	}
+
+	cam->io = rb.count ? IO_MMAP : IO_NONE;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_querybuf(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_buffer b;
+
+	if (copy_from_user(&b, arg, sizeof(b)))
+		return -EFAULT;
+
+	if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
+	    b.index >= cam->nbuffers || cam->io != IO_MMAP)
+		return -EINVAL;
+
+	memcpy(&b, &cam->frame[b.index].buf, sizeof(b));
+
+	if (cam->frame[b.index].vma_use_count)
+		b.flags |= V4L2_BUF_FLAG_MAPPED;
+
+	if (cam->frame[b.index].state == F_DONE)
+		b.flags |= V4L2_BUF_FLAG_DONE;
+	else if (cam->frame[b.index].state != F_UNUSED)
+		b.flags |= V4L2_BUF_FLAG_QUEUED;
+
+	if (copy_to_user(arg, &b, sizeof(b)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_qbuf(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_buffer b;
+	unsigned long lock_flags;
+
+	if (copy_from_user(&b, arg, sizeof(b)))
+		return -EFAULT;
+
+	if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
+	    b.index >= cam->nbuffers || cam->io != IO_MMAP)
+		return -EINVAL;
+
+	if (cam->frame[b.index].state != F_UNUSED)
+		return -EINVAL;
+
+	cam->frame[b.index].state = F_QUEUED;
+
+	spin_lock_irqsave(&cam->queue_lock, lock_flags);
+	list_add_tail(&cam->frame[b.index].frame, &cam->inqueue);
+	spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
+
+	PDBGG("Frame #%lu queued", (unsigned long)b.index);
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_dqbuf(struct zc0301_device* cam, struct file* filp,
+                    void __user * arg)
+{
+	struct v4l2_buffer b;
+	struct zc0301_frame_t *f;
+	unsigned long lock_flags;
+	long timeout;
+
+	if (copy_from_user(&b, arg, sizeof(b)))
+		return -EFAULT;
+
+	if (b.type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io!= IO_MMAP)
+		return -EINVAL;
+
+	if (list_empty(&cam->outqueue)) {
+		if (cam->stream == STREAM_OFF)
+			return -EINVAL;
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		timeout = wait_event_interruptible_timeout
+		          ( cam->wait_frame,
+		            (!list_empty(&cam->outqueue)) ||
+		            (cam->state & DEV_DISCONNECTED) ||
+		            (cam->state & DEV_MISCONFIGURED),
+		            ZC0301_FRAME_TIMEOUT );
+		if (timeout < 0)
+			return timeout;
+		if (cam->state & DEV_DISCONNECTED)
+			return -ENODEV;
+		if (!timeout || (cam->state & DEV_MISCONFIGURED))
+			return -EIO;
+	}
+
+	spin_lock_irqsave(&cam->queue_lock, lock_flags);
+	f = list_entry(cam->outqueue.next, struct zc0301_frame_t, frame);
+	list_del(cam->outqueue.next);
+	spin_unlock_irqrestore(&cam->queue_lock, lock_flags);
+
+	f->state = F_UNUSED;
+
+	memcpy(&b, &f->buf, sizeof(b));
+	if (f->vma_use_count)
+		b.flags |= V4L2_BUF_FLAG_MAPPED;
+
+	if (copy_to_user(arg, &b, sizeof(b)))
+		return -EFAULT;
+
+	PDBGG("Frame #%lu dequeued", (unsigned long)f->buf.index);
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_streamon(struct zc0301_device* cam, void __user * arg)
+{
+	int type;
+
+	if (copy_from_user(&type, arg, sizeof(type)))
+		return -EFAULT;
+
+	if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
+		return -EINVAL;
+
+	if (list_empty(&cam->inqueue))
+		return -EINVAL;
+
+	cam->stream = STREAM_ON;
+
+	DBG(3, "Stream on");
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_streamoff(struct zc0301_device* cam, void __user * arg)
+{
+	int type, err;
+
+	if (copy_from_user(&type, arg, sizeof(type)))
+		return -EFAULT;
+
+	if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
+		return -EINVAL;
+
+	if (cam->stream == STREAM_ON)
+		if ((err = zc0301_stream_interrupt(cam)))
+			return err;
+
+	zc0301_empty_framequeues(cam);
+
+	DBG(3, "Stream off");
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_g_parm(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_streamparm sp;
+
+	if (copy_from_user(&sp, arg, sizeof(sp)))
+		return -EFAULT;
+
+	if (sp.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	sp.parm.capture.extendedmode = 0;
+	sp.parm.capture.readbuffers = cam->nreadbuffers;
+
+	if (copy_to_user(arg, &sp, sizeof(sp)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+static int
+zc0301_vidioc_s_parm(struct zc0301_device* cam, void __user * arg)
+{
+	struct v4l2_streamparm sp;
+
+	if (copy_from_user(&sp, arg, sizeof(sp)))
+		return -EFAULT;
+
+	if (sp.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	sp.parm.capture.extendedmode = 0;
+
+	if (sp.parm.capture.readbuffers == 0)
+		sp.parm.capture.readbuffers = cam->nreadbuffers;
+
+	if (sp.parm.capture.readbuffers > ZC0301_MAX_FRAMES)
+		sp.parm.capture.readbuffers = ZC0301_MAX_FRAMES;
+
+	if (copy_to_user(arg, &sp, sizeof(sp)))
+		return -EFAULT;
+
+	cam->nreadbuffers = sp.parm.capture.readbuffers;
+
+	return 0;
+}
+
+
+static int zc0301_ioctl_v4l2(struct inode* inode, struct file* filp,
+                             unsigned int cmd, void __user * arg)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+
+	switch (cmd) {
+
+	case VIDIOC_QUERYCAP:
+		return zc0301_vidioc_querycap(cam, arg);
+
+	case VIDIOC_ENUMINPUT:
+		return zc0301_vidioc_enuminput(cam, arg);
+
+	case VIDIOC_G_INPUT:
+	case VIDIOC_S_INPUT:
+		return zc0301_vidioc_gs_input(cam, arg);
+
+	case VIDIOC_QUERYCTRL:
+		return zc0301_vidioc_query_ctrl(cam, arg);
+
+	case VIDIOC_G_CTRL:
+		return zc0301_vidioc_g_ctrl(cam, arg);
+
+	case VIDIOC_S_CTRL_OLD:
+	case VIDIOC_S_CTRL:
+		return zc0301_vidioc_s_ctrl(cam, arg);
+
+	case VIDIOC_CROPCAP_OLD:
+	case VIDIOC_CROPCAP:
+		return zc0301_vidioc_cropcap(cam, arg);
+
+	case VIDIOC_G_CROP:
+		return zc0301_vidioc_g_crop(cam, arg);
+
+	case VIDIOC_S_CROP:
+		return zc0301_vidioc_s_crop(cam, arg);
+
+	case VIDIOC_ENUM_FMT:
+		return zc0301_vidioc_enum_fmt(cam, arg);
+
+	case VIDIOC_G_FMT:
+		return zc0301_vidioc_g_fmt(cam, arg);
+
+	case VIDIOC_TRY_FMT:
+	case VIDIOC_S_FMT:
+		return zc0301_vidioc_try_s_fmt(cam, cmd, arg);
+
+	case VIDIOC_G_JPEGCOMP:
+		return zc0301_vidioc_g_jpegcomp(cam, arg);
+
+	case VIDIOC_S_JPEGCOMP:
+		return zc0301_vidioc_s_jpegcomp(cam, arg);
+
+	case VIDIOC_REQBUFS:
+		return zc0301_vidioc_reqbufs(cam, arg);
+
+	case VIDIOC_QUERYBUF:
+		return zc0301_vidioc_querybuf(cam, arg);
+
+	case VIDIOC_QBUF:
+		return zc0301_vidioc_qbuf(cam, arg);
+
+	case VIDIOC_DQBUF:
+		return zc0301_vidioc_dqbuf(cam, filp, arg);
+
+	case VIDIOC_STREAMON:
+		return zc0301_vidioc_streamon(cam, arg);
+
+	case VIDIOC_STREAMOFF:
+		return zc0301_vidioc_streamoff(cam, arg);
+
+	case VIDIOC_G_PARM:
+		return zc0301_vidioc_g_parm(cam, arg);
+
+	case VIDIOC_S_PARM_OLD:
+	case VIDIOC_S_PARM:
+		return zc0301_vidioc_s_parm(cam, arg);
+
+	case VIDIOC_G_STD:
+	case VIDIOC_S_STD:
+	case VIDIOC_QUERYSTD:
+	case VIDIOC_ENUMSTD:
+	case VIDIOC_QUERYMENU:
+		return -EINVAL;
+
+	default:
+		return -EINVAL;
+
+	}
+}
+
+
+static int zc0301_ioctl(struct inode* inode, struct file* filp,
+                        unsigned int cmd, unsigned long arg)
+{
+	struct zc0301_device* cam = video_get_drvdata(video_devdata(filp));
+	int err = 0;
+
+	if (mutex_lock_interruptible(&cam->fileop_mutex))
+		return -ERESTARTSYS;
+
+	if (cam->state & DEV_DISCONNECTED) {
+		DBG(1, "Device not present");
+		mutex_unlock(&cam->fileop_mutex);
+		return -ENODEV;
+	}
+
+	if (cam->state & DEV_MISCONFIGURED) {
+		DBG(1, "The camera is misconfigured. Close and open it "
+		       "again.");
+		mutex_unlock(&cam->fileop_mutex);
+		return -EIO;
+	}
+
+	V4LDBG(3, "zc0301", cmd);
+
+	err = zc0301_ioctl_v4l2(inode, filp, cmd, (void __user *)arg);
+
+	mutex_unlock(&cam->fileop_mutex);
+
+	return err;
+}
+
+
+static struct file_operations zc0301_fops = {
+	.owner =   THIS_MODULE,
+	.open =    zc0301_open,
+	.release = zc0301_release,
+	.ioctl =   zc0301_ioctl,
+	.read =    zc0301_read,
+	.poll =    zc0301_poll,
+	.mmap =    zc0301_mmap,
+	.llseek =  no_llseek,
+};
+
+/*****************************************************************************/
+
+static int
+zc0301_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
+{
+	struct usb_device *udev = interface_to_usbdev(intf);
+	struct zc0301_device* cam;
+	static unsigned int dev_nr = 0;
+	unsigned int i;
+	int err = 0;
+
+	if (!(cam = kzalloc(sizeof(struct zc0301_device), GFP_KERNEL)))
+		return -ENOMEM;
+
+	cam->usbdev = udev;
+
+	if (!(cam->control_buffer = kzalloc(4, GFP_KERNEL))) {
+		DBG(1, "kmalloc() failed");
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	if (!(cam->v4ldev = video_device_alloc())) {
+		DBG(1, "video_device_alloc() failed");
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	mutex_init(&cam->dev_mutex);
+
+	DBG(2, "ZC0301 Image Processor and Control Chip detected "
+	       "(vid/pid 0x%04X/0x%04X)",id->idVendor, id->idProduct);
+
+	for  (i = 0; zc0301_sensor_table[i]; i++) {
+		err = zc0301_sensor_table[i](cam);
+		if (!err)
+			break;
+	}
+
+	if (!err && cam->sensor)
+		DBG(2, "%s image sensor detected", cam->sensor->name);
+	else {
+		DBG(1, "No supported image sensor detected");
+		err = -ENODEV;
+		goto fail;
+	}
+
+	if (zc0301_init(cam)) {
+		DBG(1, "Initialization failed. I will retry on open().");
+		cam->state |= DEV_MISCONFIGURED;
+	}
+
+	strcpy(cam->v4ldev->name, "ZC0301 PC Camera");
+	cam->v4ldev->owner = THIS_MODULE;
+	cam->v4ldev->type = VID_TYPE_CAPTURE | VID_TYPE_SCALES;
+	cam->v4ldev->hardware = 0;
+	cam->v4ldev->fops = &zc0301_fops;
+	cam->v4ldev->minor = video_nr[dev_nr];
+	cam->v4ldev->release = video_device_release;
+	video_set_drvdata(cam->v4ldev, cam);
+
+	mutex_lock(&cam->dev_mutex);
+
+	err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
+	                            video_nr[dev_nr]);
+	if (err) {
+		DBG(1, "V4L2 device registration failed");
+		if (err == -ENFILE && video_nr[dev_nr] == -1)
+			DBG(1, "Free /dev/videoX node not found");
+		video_nr[dev_nr] = -1;
+		dev_nr = (dev_nr < ZC0301_MAX_DEVICES-1) ? dev_nr+1 : 0;
+		mutex_unlock(&cam->dev_mutex);
+		goto fail;
+	}
+
+	DBG(2, "V4L2 device registered as /dev/video%d", cam->v4ldev->minor);
+
+	cam->module_param.force_munmap = force_munmap[dev_nr];
+
+	dev_nr = (dev_nr < ZC0301_MAX_DEVICES-1) ? dev_nr+1 : 0;
+
+	usb_set_intfdata(intf, cam);
+
+	mutex_unlock(&cam->dev_mutex);
+
+	return 0;
+
+fail:
+	if (cam) {
+		kfree(cam->control_buffer);
+		if (cam->v4ldev)
+			video_device_release(cam->v4ldev);
+		kfree(cam);
+	}
+	return err;
+}
+
+
+static void zc0301_usb_disconnect(struct usb_interface* intf)
+{
+	struct zc0301_device* cam = usb_get_intfdata(intf);
+
+	if (!cam)
+		return;
+
+	down_write(&zc0301_disconnect);
+
+	mutex_lock(&cam->dev_mutex);
+
+	DBG(2, "Disconnecting %s...", cam->v4ldev->name);
+
+	wake_up_interruptible_all(&cam->open);
+
+	if (cam->users) {
+		DBG(2, "Device /dev/video%d is open! Deregistration and "
+		       "memory deallocation are deferred on close.",
+		    cam->v4ldev->minor);
+		cam->state |= DEV_MISCONFIGURED;
+		zc0301_stop_transfer(cam);
+		cam->state |= DEV_DISCONNECTED;
+		wake_up_interruptible(&cam->wait_frame);
+		wake_up_interruptible(&cam->wait_stream);
+	} else {
+		cam->state |= DEV_DISCONNECTED;
+		zc0301_release_resources(cam);
+	}
+
+	mutex_unlock(&cam->dev_mutex);
+
+	if (!cam->users)
+		kfree(cam);
+
+	up_write(&zc0301_disconnect);
+}
+
+
+static struct usb_driver zc0301_usb_driver = {
+	.name =       "zc0301",
+	.id_table =   zc0301_id_table,
+	.probe =      zc0301_usb_probe,
+	.disconnect = zc0301_usb_disconnect,
+};
+
+/*****************************************************************************/
+
+static int __init zc0301_module_init(void)
+{
+	int err = 0;
+
+	KDBG(2, ZC0301_MODULE_NAME " v" ZC0301_MODULE_VERSION);
+	KDBG(3, ZC0301_MODULE_AUTHOR);
+
+	if ((err = usb_register(&zc0301_usb_driver)))
+		KDBG(1, "usb_register() failed");
+
+	return err;
+}
+
+
+static void __exit zc0301_module_exit(void)
+{
+	usb_deregister(&zc0301_usb_driver);
+}
+
+
+module_init(zc0301_module_init);
+module_exit(zc0301_module_exit);

drivers/usb/media/zc0301_pas202bcb.c

+/***************************************************************************
+ * Plug-in for PAS202BCB image sensor connected to the ZC030! Image        *
+ * Processor and Control Chip                                              *
+ *                                                                         *
+ * Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>       *
+ *                                                                         *
+ * Initialization values of the ZC0301 have been taken from the SPCA5XX    *
+ * driver maintained by Michel Xhaard <mxhaard@magic.fr>                   *
+ *                                                                         *
+ * 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/delay.h>
+#include "zc0301_sensor.h"
+
+
+static struct zc0301_sensor pas202bcb;
+
+
+static int pas202bcb_init(struct zc0301_device* cam)
+{
+	int err = 0;
+
+	err += zc0301_write_reg(cam, 0x0002, 0x00);
+	err += zc0301_write_reg(cam, 0x0003, 0x02);
+	err += zc0301_write_reg(cam, 0x0004, 0x80);
+	err += zc0301_write_reg(cam, 0x0005, 0x01);
+	err += zc0301_write_reg(cam, 0x0006, 0xE0);
+	err += zc0301_write_reg(cam, 0x0098, 0x00);
+	err += zc0301_write_reg(cam, 0x009A, 0x03);
+	err += zc0301_write_reg(cam, 0x011A, 0x00);
+	err += zc0301_write_reg(cam, 0x011C, 0x03);
+	err += zc0301_write_reg(cam, 0x009B, 0x01);
+	err += zc0301_write_reg(cam, 0x009C, 0xE6);
+	err += zc0301_write_reg(cam, 0x009D, 0x02);
+	err += zc0301_write_reg(cam, 0x009E, 0x86);
+
+	err += zc0301_i2c_write(cam, 0x02, 0x02);
+	err += zc0301_i2c_write(cam, 0x0A, 0x01);
+	err += zc0301_i2c_write(cam, 0x0B, 0x01);
+	err += zc0301_i2c_write(cam, 0x0D, 0x00);
+	err += zc0301_i2c_write(cam, 0x12, 0x05);
+	err += zc0301_i2c_write(cam, 0x13, 0x63);
+	err += zc0301_i2c_write(cam, 0x15, 0x70);
+
+	err += zc0301_write_reg(cam, 0x0101, 0xB7);
+	err += zc0301_write_reg(cam, 0x0100, 0x0D);
+	err += zc0301_write_reg(cam, 0x0189, 0x06);
+	err += zc0301_write_reg(cam, 0x01AD, 0x00);
+	err += zc0301_write_reg(cam, 0x01C5, 0x03);
+	err += zc0301_write_reg(cam, 0x01CB, 0x13);
+	err += zc0301_write_reg(cam, 0x0250, 0x08);
+	err += zc0301_write_reg(cam, 0x0301, 0x08);
+	err += zc0301_write_reg(cam, 0x018D, 0x70);
+	err += zc0301_write_reg(cam, 0x0008, 0x03);
+	err += zc0301_write_reg(cam, 0x01C6, 0x04);
+	err += zc0301_write_reg(cam, 0x01CB, 0x07);
+	err += zc0301_write_reg(cam, 0x0120, 0x11);
+	err += zc0301_write_reg(cam, 0x0121, 0x37);
+	err += zc0301_write_reg(cam, 0x0122, 0x58);
+	err += zc0301_write_reg(cam, 0x0123, 0x79);
+	err += zc0301_write_reg(cam, 0x0124, 0x91);
+	err += zc0301_write_reg(cam, 0x0125, 0xA6);
+	err += zc0301_write_reg(cam, 0x0126, 0xB8);
+	err += zc0301_write_reg(cam, 0x0127, 0xC7);
+	err += zc0301_write_reg(cam, 0x0128, 0xD3);
+	err += zc0301_write_reg(cam, 0x0129, 0xDE);
+	err += zc0301_write_reg(cam, 0x012A, 0xE6);
+	err += zc0301_write_reg(cam, 0x012B, 0xED);
+	err += zc0301_write_reg(cam, 0x012C, 0xF3);
+	err += zc0301_write_reg(cam, 0x012D, 0xF8);
+	err += zc0301_write_reg(cam, 0x012E, 0xFB);
+	err += zc0301_write_reg(cam, 0x012F, 0xFF);
+	err += zc0301_write_reg(cam, 0x0130, 0x26);
+	err += zc0301_write_reg(cam, 0x0131, 0x23);
+	err += zc0301_write_reg(cam, 0x0132, 0x20);
+	err += zc0301_write_reg(cam, 0x0133, 0x1C);
+	err += zc0301_write_reg(cam, 0x0134, 0x16);
+	err += zc0301_write_reg(cam, 0x0135, 0x13);
+	err += zc0301_write_reg(cam, 0x0136, 0x10);
+	err += zc0301_write_reg(cam, 0x0137, 0x0D);
+	err += zc0301_write_reg(cam, 0x0138, 0x0B);
+	err += zc0301_write_reg(cam, 0x0139, 0x09);
+	err += zc0301_write_reg(cam, 0x013A, 0x07);
+	err += zc0301_write_reg(cam, 0x013B, 0x06);
+	err += zc0301_write_reg(cam, 0x013C, 0x05);
+	err += zc0301_write_reg(cam, 0x013D, 0x04);
+	err += zc0301_write_reg(cam, 0x013E, 0x03);
+	err += zc0301_write_reg(cam, 0x013F, 0x02);
+	err += zc0301_write_reg(cam, 0x010A, 0x4C);
+	err += zc0301_write_reg(cam, 0x010B, 0xF5);
+	err += zc0301_write_reg(cam, 0x010C, 0xFF);
+	err += zc0301_write_reg(cam, 0x010D, 0xF9);
+	err += zc0301_write_reg(cam, 0x010E, 0x51);
+	err += zc0301_write_reg(cam, 0x010F, 0xF5);
+	err += zc0301_write_reg(cam, 0x0110, 0xFB);
+	err += zc0301_write_reg(cam, 0x0111, 0xED);
+	err += zc0301_write_reg(cam, 0x0112, 0x5F);
+	err += zc0301_write_reg(cam, 0x0180, 0x00);
+	err += zc0301_write_reg(cam, 0x0019, 0x00);
+	err += zc0301_write_reg(cam, 0x0087, 0x20);
+	err += zc0301_write_reg(cam, 0x0088, 0x21);
+
+	err += zc0301_i2c_write(cam, 0x20, 0x02);
+	err += zc0301_i2c_write(cam, 0x21, 0x1B);
+	err += zc0301_i2c_write(cam, 0x03, 0x44);
+	err += zc0301_i2c_write(cam, 0x0E, 0x01);
+	err += zc0301_i2c_write(cam, 0x0F, 0x00);
+
+	err += zc0301_write_reg(cam, 0x01A9, 0x14);
+	err += zc0301_write_reg(cam, 0x01AA, 0x24);
+	err += zc0301_write_reg(cam, 0x0190, 0x00);
+	err += zc0301_write_reg(cam, 0x0191, 0x02);
+	err += zc0301_write_reg(cam, 0x0192, 0x1B);
+	err += zc0301_write_reg(cam, 0x0195, 0x00);
+	err += zc0301_write_reg(cam, 0x0196, 0x00);
+	err += zc0301_write_reg(cam, 0x0197, 0x4D);
+	err += zc0301_write_reg(cam, 0x018C, 0x10);
+	err += zc0301_write_reg(cam, 0x018F, 0x20);
+	err += zc0301_write_reg(cam, 0x001D, 0x44);
+	err += zc0301_write_reg(cam, 0x001E, 0x6F);
+	err += zc0301_write_reg(cam, 0x001F, 0xAD);
+	err += zc0301_write_reg(cam, 0x0020, 0xEB);
+	err += zc0301_write_reg(cam, 0x0087, 0x0F);
+	err += zc0301_write_reg(cam, 0x0088, 0x0E);
+	err += zc0301_write_reg(cam, 0x0180, 0x40);
+	err += zc0301_write_reg(cam, 0x0192, 0x1B);
+	err += zc0301_write_reg(cam, 0x0191, 0x02);
+	err += zc0301_write_reg(cam, 0x0190, 0x00);
+	err += zc0301_write_reg(cam, 0x0116, 0x1D);
+	err += zc0301_write_reg(cam, 0x0117, 0x40);
+	err += zc0301_write_reg(cam, 0x0118, 0x99);
+	err += zc0301_write_reg(cam, 0x0180, 0x42);
+	err += zc0301_write_reg(cam, 0x0116, 0x1D);
+	err += zc0301_write_reg(cam, 0x0117, 0x40);
+	err += zc0301_write_reg(cam, 0x0118, 0x99);
+	err += zc0301_write_reg(cam, 0x0007, 0x00);
+
+	err += zc0301_i2c_write(cam, 0x11, 0x01);
+
+	msleep(100);
+
+	return err;
+}
+
+
+static int pas202bcb_get_ctrl(struct zc0301_device* cam,
+                              struct v4l2_control* ctrl)
+{
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		{
+			int r1 = zc0301_i2c_read(cam, 0x04, 1),
+			    r2 = zc0301_i2c_read(cam, 0x05, 1);
+			if (r1 < 0 || r2 < 0)
+				return -EIO;
+			ctrl->value = (r1 << 6) | (r2 & 0x3f);
+		}
+		return 0;
+	case V4L2_CID_RED_BALANCE:
+		if ((ctrl->value = zc0301_i2c_read(cam, 0x09, 1)) < 0)
+			return -EIO;
+		ctrl->value &= 0x0f;
+		return 0;
+	case V4L2_CID_BLUE_BALANCE:
+		if ((ctrl->value = zc0301_i2c_read(cam, 0x07, 1)) < 0)
+			return -EIO;
+		ctrl->value &= 0x0f;
+		return 0;
+	case V4L2_CID_GAIN:
+		if ((ctrl->value = zc0301_i2c_read(cam, 0x10, 1)) < 0)
+			return -EIO;
+		ctrl->value &= 0x1f;
+		return 0;
+	case ZC0301_V4L2_CID_GREEN_BALANCE:
+		if ((ctrl->value = zc0301_i2c_read(cam, 0x08, 1)) < 0)
+			return -EIO;
+		ctrl->value &= 0x0f;
+		return 0;
+	case ZC0301_V4L2_CID_DAC_MAGNITUDE:
+		if ((ctrl->value = zc0301_i2c_read(cam, 0x0c, 1)) < 0)
+			return -EIO;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+
+static int pas202bcb_set_ctrl(struct zc0301_device* cam,
+                              const struct v4l2_control* ctrl)
+{
+	int err = 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		err += zc0301_i2c_write(cam, 0x04, ctrl->value >> 6);
+		err += zc0301_i2c_write(cam, 0x05, ctrl->value & 0x3f);
+		break;
+	case V4L2_CID_RED_BALANCE:
+		err += zc0301_i2c_write(cam, 0x09, ctrl->value);
+		break;
+	case V4L2_CID_BLUE_BALANCE:
+		err += zc0301_i2c_write(cam, 0x07, ctrl->value);
+		break;
+	case V4L2_CID_GAIN:
+		err += zc0301_i2c_write(cam, 0x10, ctrl->value);
+		break;
+	case ZC0301_V4L2_CID_GREEN_BALANCE:
+		err += zc0301_i2c_write(cam, 0x08, ctrl->value);
+		break;
+	case ZC0301_V4L2_CID_DAC_MAGNITUDE:
+		err += zc0301_i2c_write(cam, 0x0c, ctrl->value);
+		break;
+	default:
+		return -EINVAL;
+	}
+	err += zc0301_i2c_write(cam, 0x11, 0x01);
+
+	return err ? -EIO : 0;
+}
+
+
+static struct zc0301_sensor pas202bcb = {
+	.name = "PAS202BCB",
+	.init = &pas202bcb_init,
+	.qctrl = {
+		{
+			.id = V4L2_CID_EXPOSURE,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "exposure",
+			.minimum = 0x01e5,
+			.maximum = 0x3fff,
+			.step = 0x0001,
+			.default_value = 0x01e5,
+			.flags = 0,
+		},
+		{
+			.id = V4L2_CID_GAIN,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "global gain",
+			.minimum = 0x00,
+			.maximum = 0x1f,
+			.step = 0x01,
+			.default_value = 0x0c,
+			.flags = 0,
+		},
+		{
+			.id = V4L2_CID_RED_BALANCE,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "red balance",
+			.minimum = 0x00,
+			.maximum = 0x0f,
+			.step = 0x01,
+			.default_value = 0x01,
+			.flags = 0,
+		},
+		{
+			.id = V4L2_CID_BLUE_BALANCE,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "blue balance",
+			.minimum = 0x00,
+			.maximum = 0x0f,
+			.step = 0x01,
+			.default_value = 0x05,
+			.flags = 0,
+		},
+		{
+			.id = ZC0301_V4L2_CID_GREEN_BALANCE,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "green balance",
+			.minimum = 0x00,
+			.maximum = 0x0f,
+			.step = 0x01,
+			.default_value = 0x00,
+			.flags = 0,
+		},
+		{
+			.id = ZC0301_V4L2_CID_DAC_MAGNITUDE,
+			.type = V4L2_CTRL_TYPE_INTEGER,
+			.name = "DAC magnitude",
+			.minimum = 0x00,
+			.maximum = 0xff,
+			.step = 0x01,
+			.default_value = 0x04,
+			.flags = 0,
+		},
+	},
+	.get_ctrl = &pas202bcb_get_ctrl,
+	.set_ctrl = &pas202bcb_set_ctrl,
+	.cropcap = {
+		.bounds = {
+			.left = 0,
+			.top = 0,
+			.width = 640,
+			.height = 480,
+		},
+		.defrect = {
+			.left = 0,
+			.top = 0,
+			.width = 640,
+			.height = 480,
+		},
+	},
+	.pix_format = {
+		.width = 640,
+		.height = 480,
+		.pixelformat = V4L2_PIX_FMT_JPEG,
+		.priv = 16,
+	},
+};
+
+
+int zc0301_probe_pas202bcb(struct zc0301_device* cam)
+{
+	int r0 = 0, r1 = 0, err = 0;
+	unsigned int pid = 0;
+
+	err += zc0301_write_reg(cam, 0x0000, 0x01);
+	err += zc0301_write_reg(cam, 0x0010, 0x0e);
+	err += zc0301_write_reg(cam, 0x0001, 0x01);
+	err += zc0301_write_reg(cam, 0x0012, 0x03);
+	err += zc0301_write_reg(cam, 0x0012, 0x01);
+	err += zc0301_write_reg(cam, 0x008d, 0x08);
+
+	msleep(10);
+
+	r0 = zc0301_i2c_read(cam, 0x00, 1);
+	r1 = zc0301_i2c_read(cam, 0x01, 1);
+
+	if (r0 < 0 || r1 < 0 || err)
+		return -EIO;
+
+	pid = (r0 << 4) | ((r1 & 0xf0) >> 4);
+	if (pid != 0x017)
+		return -ENODEV;
+
+	zc0301_attach_sensor(cam, &pas202bcb);
+
+	return 0;
+}

drivers/usb/media/zc0301_sensor.h

+/***************************************************************************
+ * API for image sensors connected to the ZC030! Image Processor and       *
+ * Control Chip                                                            *
+ *                                                                         *
+ * Copyright (C) 2006 by Luca Risolia <luca.risolia@studio.unibo.it>       *
+ *                                                                         *
+ * This program is free software; you can redistribute it and/or modify    *
+ * it under the terms of the GNU General Public License as published by    *
+ * the Free Software Foundation; either version 2 of the License, or       *
+ * (at your option) any later version.                                     *
+ *                                                                         *
+ * This program is distributed in the hope that it will be useful,         *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
+ * GNU General Public License for more details.                            *
+ *                                                                         *
+ * You should have received a copy of the GNU General Public License       *
+ * along with this program; if not, write to the Free Software             *
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.               *
+ ***************************************************************************/
+
+#ifndef _ZC0301_SENSOR_H_
+#define _ZC0301_SENSOR_H_
+
+#include <linux/usb.h>
+#include <linux/videodev.h>
+#include <linux/device.h>
+#include <linux/stddef.h>
+#include <linux/errno.h>
+#include <asm/types.h>
+
+struct zc0301_device;
+struct zc0301_sensor;
+
+/*****************************************************************************/
+
+extern int zc0301_probe_pas202bcb(struct zc0301_device* cam);
+
+#define ZC0301_SENSOR_TABLE                                                   \
+/* Weak detections must go at the end of the list */                          \
+static int (*zc0301_sensor_table[])(struct zc0301_device*) = {                \
+	&zc0301_probe_pas202bcb,                                              \
+	NULL,                                                                 \
+};
+
+extern void
+zc0301_attach_sensor(struct zc0301_device* cam,
+                       struct zc0301_sensor* sensor);
+
+#define ZC0301_USB_DEVICE(vend, prod, intclass)                               \
+	.match_flags = USB_DEVICE_ID_MATCH_DEVICE |                           \
+	               USB_DEVICE_ID_MATCH_INT_CLASS,                         \
+	.idVendor = (vend),                                                   \
+	.idProduct = (prod),                                                  \
+	.bInterfaceClass = (intclass)
+
+#define ZC0301_ID_TABLE                                                       \
+static const struct usb_device_id zc0301_id_table[] =  {                      \
+	{ ZC0301_USB_DEVICE(0x046d, 0x08ae, 0xff), }, /* PAS202BCB */         \
+	{ }                                                                   \
+};
+
+/*****************************************************************************/
+
+extern int zc0301_write_reg(struct zc0301_device*, u16 index, u16 value);
+extern int zc0301_read_reg(struct zc0301_device*, u16 index);
+extern int zc0301_i2c_write(struct zc0301_device*, u16 address, u16 value);
+extern int zc0301_i2c_read(struct zc0301_device*, u16 address, u8 length);
+
+/*****************************************************************************/
+
+#define ZC0301_MAX_CTRLS V4L2_CID_LASTP1-V4L2_CID_BASE+10
+#define ZC0301_V4L2_CID_DAC_MAGNITUDE V4L2_CID_PRIVATE_BASE
+#define ZC0301_V4L2_CID_GREEN_BALANCE V4L2_CID_PRIVATE_BASE + 1
+
+struct zc0301_sensor {
+	char name[32];
+
+	struct v4l2_queryctrl qctrl[ZC0301_MAX_CTRLS];
+	struct v4l2_cropcap cropcap;
+	struct v4l2_pix_format pix_format;
+
+	int (*init)(struct zc0301_device* cam);
+	int (*get_ctrl)(struct zc0301_device* cam,
+	                struct v4l2_control* ctrl);
+	int (*set_ctrl)(struct zc0301_device* cam,
+	                const struct v4l2_control* ctrl);
+	int (*set_crop)(struct zc0301_device* cam,
+	                const struct v4l2_rect* rect);
+
+	const struct usb_device* usbdev;
+
+	/* Private */
+	struct v4l2_queryctrl _qctrl[ZC0301_MAX_CTRLS];
+	struct v4l2_rect _rect;
+};
+
+#endif /* _ZC0301_SENSOR_H_ */