[PATCH] USB: Add ET61X[12]51 Video4Linux2 driver

This patch adds a Video4Linux2 driver giving support
to ET61X151 and ET61X251 PC Camera Controllers made by
Etoms Electronics.

Signed-off-by: Luca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

6 files changed, 3094 insertions, 2 deletions

diff --git a/drivers/usb/media/Kconfig b/drivers/usb/media/Kconfig
index 21232ee2974..0d3d2cc5d7b 100644
--- a/drivers/usb/media/Kconfig
+++ b/drivers/usb/media/Kconfig
@@ -53,6 +53,21 @@ config USB_DSBR
 	  To compile this driver as a module, choose M here: the
 	  module will be called dsbr100.
 
+config USB_ET61X251
+	tristate "USB ET61X[12]51 PC Camera Controller support"
+	depends on USB && VIDEO_DEV
+	---help---
+	  Say Y here if you want support for cameras based on Etoms ET61X151
+	  or ET61X251 PC Camera Controllers.
+
+	  See <file:Documentation/usb/et61x251.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 et61x251.
+
 config USB_IBMCAM
 	tristate "USB IBM (Xirlink) C-it Camera support"
 	depends on USB && VIDEO_DEV
@@ -209,5 +224,3 @@ config USB_PWC
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called pwc.
-
-
diff --git a/drivers/usb/media/Makefile b/drivers/usb/media/Makefile
index d83adffa925..3957aa1be0f 100644
--- a/drivers/usb/media/Makefile
+++ b/drivers/usb/media/Makefile
@@ -3,9 +3,11 @@
 #
 
 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
 
 obj-$(CONFIG_USB_DABUSB)	+= dabusb.o
 obj-$(CONFIG_USB_DSBR)		+= dsbr100.o
+obj-$(CONFIG_USB_ET61X251)	+= et61x251.o
 obj-$(CONFIG_USB_IBMCAM)	+= ibmcam.o usbvideo.o ultracam.o
 obj-$(CONFIG_USB_KONICAWC)	+= konicawc.o usbvideo.o
 obj-$(CONFIG_USB_OV511)		+= ov511.o
diff --git a/drivers/usb/media/et61x251.h b/drivers/usb/media/et61x251.h
new file mode 100644
index 00000000000..652238f329f
--- /dev/null
+++ b/drivers/usb/media/et61x251.h
@@ -0,0 +1,220 @@
+/***************************************************************************
+ * V4L2 driver for ET61X[12]51 PC Camera Controllers                       *
+ *                                                                         *
+ * 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 _ET61X251_H_
+#define _ET61X251_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/rwsem.h>
+#include <asm/semaphore.h>
+
+#include "et61x251_sensor.h"
+
+/*****************************************************************************/
+
+#define ET61X251_DEBUG
+#define ET61X251_DEBUG_LEVEL         2
+#define ET61X251_MAX_DEVICES         64
+#define ET61X251_PRESERVE_IMGSCALE   0
+#define ET61X251_FORCE_MUNMAP        0
+#define ET61X251_MAX_FRAMES          32
+#define ET61X251_COMPRESSION_QUALITY 0
+#define ET61X251_URBS                2
+#define ET61X251_ISO_PACKETS         7
+#define ET61X251_ALTERNATE_SETTING   13
+#define ET61X251_URB_TIMEOUT         msecs_to_jiffies(2 * ET61X251_ISO_PACKETS)
+#define ET61X251_CTRL_TIMEOUT        100
+
+/*****************************************************************************/
+
+static const struct usb_device_id et61x251_id_table[] = {
+	{ USB_DEVICE(0x102c, 0x6151), },
+	{ USB_DEVICE(0x102c, 0x6251), },
+	{ USB_DEVICE(0x102c, 0x6253), },
+	{ USB_DEVICE(0x102c, 0x6254), },
+	{ USB_DEVICE(0x102c, 0x6255), },
+	{ USB_DEVICE(0x102c, 0x6256), },
+	{ USB_DEVICE(0x102c, 0x6257), },
+	{ USB_DEVICE(0x102c, 0x6258), },
+	{ USB_DEVICE(0x102c, 0x6259), },
+	{ USB_DEVICE(0x102c, 0x625a), },
+	{ USB_DEVICE(0x102c, 0x625b), },
+	{ USB_DEVICE(0x102c, 0x625c), },
+	{ USB_DEVICE(0x102c, 0x625d), },
+	{ USB_DEVICE(0x102c, 0x625e), },
+	{ USB_DEVICE(0x102c, 0x625f), },
+	{ USB_DEVICE(0x102c, 0x6260), },
+	{ USB_DEVICE(0x102c, 0x6261), },
+	{ USB_DEVICE(0x102c, 0x6262), },
+	{ USB_DEVICE(0x102c, 0x6263), },
+	{ USB_DEVICE(0x102c, 0x6264), },
+	{ USB_DEVICE(0x102c, 0x6265), },
+	{ USB_DEVICE(0x102c, 0x6266), },
+	{ USB_DEVICE(0x102c, 0x6267), },
+	{ USB_DEVICE(0x102c, 0x6268), },
+	{ USB_DEVICE(0x102c, 0x6269), },
+	{ }
+};
+
+ET61X251_SENSOR_TABLE
+
+/*****************************************************************************/
+
+enum et61x251_frame_state {
+	F_UNUSED,
+	F_QUEUED,
+	F_GRABBING,
+	F_DONE,
+	F_ERROR,
+};
+
+struct et61x251_frame_t {
+	void* bufmem;
+	struct v4l2_buffer buf;
+	enum et61x251_frame_state state;
+	struct list_head frame;
+	unsigned long vma_use_count;
+};
+
+enum et61x251_dev_state {
+	DEV_INITIALIZED = 0x01,
+	DEV_DISCONNECTED = 0x02,
+	DEV_MISCONFIGURED = 0x04,
+};
+
+enum et61x251_io_method {
+	IO_NONE,
+	IO_READ,
+	IO_MMAP,
+};
+
+enum et61x251_stream_state {
+	STREAM_OFF,
+	STREAM_INTERRUPT,
+	STREAM_ON,
+};
+
+struct et61x251_sysfs_attr {
+	u8 reg, i2c_reg;
+};
+
+struct et61x251_module_param {
+	u8 force_munmap;
+};
+
+static DECLARE_MUTEX(et61x251_sysfs_lock);
+static DECLARE_RWSEM(et61x251_disconnect);
+
+struct et61x251_device {
+	struct video_device* v4ldev;
+
+	struct et61x251_sensor* sensor;
+
+	struct usb_device* usbdev;
+	struct urb* urb[ET61X251_URBS];
+	void* transfer_buffer[ET61X251_URBS];
+	u8* control_buffer;
+
+	struct et61x251_frame_t *frame_current, frame[ET61X251_MAX_FRAMES];
+	struct list_head inqueue, outqueue;
+	u32 frame_count, nbuffers, nreadbuffers;
+
+	enum et61x251_io_method io;
+	enum et61x251_stream_state stream;
+
+	struct v4l2_jpegcompression compression;
+
+	struct et61x251_sysfs_attr sysfs;
+	struct et61x251_module_param module_param;
+
+	enum et61x251_dev_state state;
+	u8 users;
+
+	struct semaphore dev_sem, fileop_sem;
+	spinlock_t queue_lock;
+	wait_queue_head_t open, wait_frame, wait_stream;
+};
+
+/*****************************************************************************/
+
+void
+et61x251_attach_sensor(struct et61x251_device* cam,
+                       struct et61x251_sensor* sensor)
+{
+	cam->sensor = sensor;
+	cam->sensor->usbdev = cam->usbdev;
+}
+
+/*****************************************************************************/
+
+#undef DBG
+#undef KDBG
+#ifdef ET61X251_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("et61x251: " fmt "\n", ## args);              \
+		else if ((level) == 3)                                        \
+			pr_debug("et61x251: [%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->dev, "[%s:%d] " fmt "\n", __FUNCTION__, __LINE__ , ## args)
+
+#undef PDBGG
+#define PDBGG(fmt, args...) do {;} while(0) /* placeholder */
+
+#endif /* _ET61X251_H_ */
diff --git a/drivers/usb/media/et61x251_core.c b/drivers/usb/media/et61x251_core.c
new file mode 100644
index 00000000000..2c0171a5ad6
--- /dev/null
+++ b/drivers/usb/media/et61x251_core.c
@@ -0,0 +1,2605 @@
+/***************************************************************************
+ * V4L2 driver for ET61X[12]51 PC Camera Controllers                       *
+ *                                                                         *
+ * 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.               *
+ ***************************************************************************/
+
+#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 "et61x251.h"
+
+/*****************************************************************************/
+
+#define ET61X251_MODULE_NAME    "V4L2 driver for ET61X[12]51 "                \
+                                "PC Camera Controllers"
+#define ET61X251_MODULE_AUTHOR  "(C) 2006 Luca Risolia"
+#define ET61X251_AUTHOR_EMAIL   "<luca.risolia@studio.unibo.it>"
+#define ET61X251_MODULE_LICENSE "GPL"
+#define ET61X251_MODULE_VERSION "1:1.01"
+#define ET61X251_MODULE_VERSION_CODE  KERNEL_VERSION(1, 0, 1)
+
+/*****************************************************************************/
+
+MODULE_DEVICE_TABLE(usb, et61x251_id_table);
+
+MODULE_AUTHOR(ET61X251_MODULE_AUTHOR " " ET61X251_AUTHOR_EMAIL);
+MODULE_DESCRIPTION(ET61X251_MODULE_NAME);
+MODULE_VERSION(ET61X251_MODULE_VERSION);
+MODULE_LICENSE(ET61X251_MODULE_LICENSE);
+
+static short video_nr[] = {[0 ... ET61X251_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(ET61X251_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 ... ET61X251_MAX_DEVICES-1] =
+                               ET61X251_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 ET61X251_DEBUG
+static unsigned short debug = ET61X251_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(ET61X251_DEBUG_LEVEL)"."
+                 "\n");
+#endif
+
+/*****************************************************************************/
+
+static u32
+et61x251_request_buffers(struct et61x251_device* cam, u32 count,
+                         enum et61x251_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 > ET61X251_MAX_FRAMES)
+		count = ET61X251_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 et61x251_release_buffers(struct et61x251_device* cam)
+{
+	if (cam->nbuffers) {
+		vfree(cam->frame[0].bufmem);
+		cam->nbuffers = 0;
+	}
+	cam->frame_current = NULL;
+}
+
+
+static void et61x251_empty_framequeues(struct et61x251_device* cam)
+{
+	u32 i;
+
+	INIT_LIST_HEAD(&cam->inqueue);
+	INIT_LIST_HEAD(&cam->outqueue);
+
+	for (i = 0; i < ET61X251_MAX_FRAMES; i++) {
+		cam->frame[i].state = F_UNUSED;
+		cam->frame[i].buf.bytesused = 0;
+	}
+}
+
+
+static void et61x251_requeue_outqueue(struct et61x251_device* cam)
+{
+	struct et61x251_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 et61x251_queue_unusedframes(struct et61x251_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 et61x251_write_reg(struct et61x251_device* cam, u8 value, u16 index)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* buff = cam->control_buffer;
+	int res;
+
+	*buff = value;
+
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, index, buff, 1, ET61X251_CTRL_TIMEOUT);
+	if (res < 0) {
+		DBG(3, "Failed to write a register (value 0x%02X, index "
+		       "0x%02X, error %d)", value, index, res);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int et61x251_read_reg(struct et61x251_device* cam, u16 index)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* buff = cam->control_buffer;
+	int res;
+
+	res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0x00, 0xc1,
+	                      0, index, buff, 1, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		DBG(3, "Failed to read a register (index 0x%02X, error %d)",
+		    index, res);
+
+	return (res >= 0) ? (int)(*buff) : -1;
+}
+
+
+static int
+et61x251_i2c_wait(struct et61x251_device* cam, struct et61x251_sensor* sensor)
+{
+	int i, r;
+
+	for (i = 1; i <= 8; i++) {
+		if (sensor->interface == ET61X251_I2C_3WIRES) {
+			r = et61x251_read_reg(cam, 0x8e);
+			if (!(r & 0x02) && (r >= 0))
+				return 0;
+		} else {
+			r = et61x251_read_reg(cam, 0x8b);
+			if (!(r & 0x01) && (r >= 0))
+				return 0;
+		}
+		if (r < 0)
+			return -EIO;
+		udelay(8*8); /* minimum for sensors at 400kHz */
+	}
+
+	return -EBUSY;
+}
+
+
+int
+et61x251_i2c_try_read(struct et61x251_device* cam,
+                      struct et61x251_sensor* sensor, u8 address)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* data = cam->control_buffer;
+	int err = 0, res;
+
+	data[0] = address;
+	data[1] = cam->sensor->i2c_slave_id;
+	data[2] = cam->sensor->rsta | 0x10;
+	data[3] = !(et61x251_read_reg(cam, 0x8b) & 0x02);
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x88, data, 4, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	err += et61x251_i2c_wait(cam, sensor);
+
+	res = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), 0x00, 0xc1,
+	                      0, 0x80, data, 8, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	if (err)
+		DBG(3, "I2C read failed for %s image sensor", sensor->name);
+
+	PDBGG("I2C read: address 0x%02X, value: 0x%02X", address, data[0]);
+
+	return err ? -1 : (int)data[0];
+}
+
+
+int
+et61x251_i2c_try_write(struct et61x251_device* cam,
+                       struct et61x251_sensor* sensor, u8 address, u8 value)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* data = cam->control_buffer;
+	int err = 0, res;
+
+	data[0] = address;
+	data[1] = cam->sensor->i2c_slave_id;
+	data[2] = cam->sensor->rsta | 0x12;
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x88, data, 3, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	data[0] = value;
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x80, data, 1, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	err += et61x251_i2c_wait(cam, sensor);
+
+	if (err)
+		DBG(3, "I2C write failed for %s image sensor", sensor->name);
+
+	PDBGG("I2C write: address 0x%02X, value: 0x%02X", address, value);
+
+	return err ? -1 : 0;
+}
+
+
+int
+et61x251_i2c_raw_write(struct et61x251_device* cam, u8 n, u8 data1, u8 data2,
+                       u8 data3, u8 data4, u8 data5, u8 data6, u8 data7,
+                       u8 data8, u8 address)
+{
+	struct usb_device* udev = cam->usbdev;
+	u8* data = cam->control_buffer;
+	int err = 0, res;
+
+	if (!cam->sensor)
+		return -1;
+
+	data[0] = data2;
+	data[1] = data3;
+	data[2] = data4;
+	data[3] = data5;
+	data[4] = data6;
+	data[5] = data7;
+	data[6] = data8;
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x81, data, n-1, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	data[0] = address;
+	data[1] = cam->sensor->i2c_slave_id;
+	data[2] = cam->sensor->rsta | 0x02 | (n << 4);
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x88, data, 3, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	/* Start writing through the serial interface */
+	data[0] = data1;
+	res = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0x00, 0x41,
+	                      0, 0x80, data, 1, ET61X251_CTRL_TIMEOUT);
+	if (res < 0)
+		err += res;
+
+	err += et61x251_i2c_wait(cam, cam->sensor);
+
+	if (err)
+		DBG(3, "I2C raw write failed for %s image sensor",
+		    cam->sensor->name);
+
+	PDBGG("I2C raw write: %u bytes, address = 0x%02X, data1 = 0x%02X, "
+	      "data2 = 0x%02X, data3 = 0x%02X, data4 = 0x%02X, data5 = 0x%02X,"
+	      " data6 = 0x%02X, data7 = 0x%02X, data8 = 0x%02X", n, address,
+	      data1, data2, data3, data4, data5, data6, data7, data8);
+
+	return err ? -1 : 0;
+
+}
+
+
+int et61x251_i2c_read(struct et61x251_device* cam, u8 address)
+{
+	if (!cam->sensor)
+		return -1;
+
+	return et61x251_i2c_try_read(cam, cam->sensor, address);
+}
+
+
+int et61x251_i2c_write(struct et61x251_device* cam, u8 address, u8 value)
+{
+	if (!cam->sensor)
+		return -1;
+
+	return et61x251_i2c_try_write(cam, cam->sensor, address, value);
+}
+
+/*****************************************************************************/
+
+static void et61x251_urb_complete(struct urb *urb, struct pt_regs* regs)
+{
+	struct et61x251_device* cam = urb->context;
+	struct et61x251_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 et61x251_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;
+		u8* b1, * b2, sof;
+		const u8 VOID_BYTES = 6;
+		size_t imglen;
+
+		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;
+		}
+
+		b1 = pos++;
+		b2 = pos++;
+		sof = ((*b1 & 0x3f) == 63);
+		imglen = ((*b1 & 0xc0) << 2) | *b2;
+
+		PDBGG("Isochrnous frame: length %u, #%u i, image length %zu",
+		      len, i, imglen);
+
+		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);
+				pos += 22;
+				DBG(3, "SOF detected: new video frame");
+			}
+
+		if ((*f)->state == F_GRABBING) {
+			if (sof && (*f)->buf.bytesused) {
+				if (cam->sensor->pix_format.pixelformat ==
+				                         V4L2_PIX_FMT_ET61X251)
+					goto end_of_frame;
+				else {
+					DBG(3, "Not expected SOF detected "
+					       "after %lu bytes",
+					   (unsigned long)(*f)->buf.bytesused);
+					(*f)->state = F_ERROR;
+					continue;
+				}
+			}
+
+			if ((*f)->buf.bytesused + imglen > imagesize) {
+				DBG(3, "Video frame size exceeded");
+				(*f)->state = F_ERROR;
+				continue;
+			}
+
+			pos += VOID_BYTES;
+
+			memcpy((*f)->bufmem+(*f)->buf.bytesused, pos, imglen);
+			(*f)->buf.bytesused += imglen;
+
+			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 et61x251_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 &&
+				    cam->sensor->pix_format.pixelformat ==
+				                         V4L2_PIX_FMT_ET61X251)
+					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 et61x251_start_transfer(struct et61x251_device* cam)
+{
+	struct usb_device *udev = cam->usbdev;
+	struct urb* urb;
+	const unsigned int wMaxPacketSize[] = {0, 256, 384, 512, 640, 768, 832,
+	                                       864, 896, 920, 956, 980, 1000,
+	                                       1022};
+	const unsigned int psz = wMaxPacketSize[ET61X251_ALTERNATE_SETTING];
+	s8 i, j;
+	int err = 0;
+
+	for (i = 0; i < ET61X251_URBS; i++) {
+		cam->transfer_buffer[i] = kzalloc(ET61X251_ISO_PACKETS * psz,
+		                                  GFP_KERNEL);
+		if (!cam->transfer_buffer[i]) {
+			err = -ENOMEM;
+			DBG(1, "Not enough memory");
+			goto free_buffers;
+		}
+	}
+
+	for (i = 0; i < ET61X251_URBS; i++) {
+		urb = usb_alloc_urb(ET61X251_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 = ET61X251_ISO_PACKETS;
+		urb->complete = et61x251_urb_complete;
+		urb->transfer_buffer = cam->transfer_buffer[i];
+		urb->transfer_buffer_length = psz * ET61X251_ISO_PACKETS;
+		urb->interval = 1;
+		for (j = 0; j < ET61X251_ISO_PACKETS; j++) {
+			urb->iso_frame_desc[j].offset = psz * j;
+			urb->iso_frame_desc[j].length = psz;
+		}
+	}
+
+	err = et61x251_write_reg(cam, 0x01, 0x03);
+	err = et61x251_write_reg(cam, 0x00, 0x03);
+	err = et61x251_write_reg(cam, 0x08, 0x03);
+	if (err) {
+		err = -EIO;
+		DBG(1, "I/O hardware error");
+		goto free_urbs;
+	}
+
+	err = usb_set_interface(udev, 0, ET61X251_ALTERNATE_SETTING);
+	if (err) {
+		DBG(1, "usb_set_interface() failed");
+		goto free_urbs;
+	}
+
+	cam->frame_current = NULL;
+
+	for (i = 0; i < ET61X251_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 < ET61X251_URBS) &&  cam->urb[i]; i++)
+		usb_free_urb(cam->urb[i]);
+
+free_buffers:
+	for (i = 0; (i < ET61X251_URBS) && cam->transfer_buffer[i]; i++)
+		kfree(cam->transfer_buffer[i]);
+
+	return err;
+}
+
+
+static int et61x251_stop_transfer(struct et61x251_device* cam)
+{
+	struct usb_device *udev = cam->usbdev;
+	s8 i;
+	int err = 0;
+
+	if (cam->state & DEV_DISCONNECTED)
+		return 0;
+
+	for (i = ET61X251_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 et61x251_stream_interrupt(struct et61x251_device* cam)
+{
+	int err = 0;
+
+	cam->stream = STREAM_INTERRUPT;
+	err = wait_event_timeout(cam->wait_stream,
+	                         (cam->stream == STREAM_OFF) ||
+	                         (cam->state & DEV_DISCONNECTED),
+	                         ET61X251_URB_TIMEOUT);
+	if (cam->state & DEV_DISCONNECTED)
+		return -ENODEV;
+	else if (err) {
+		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 err;
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+static u8 et61x251_strtou8(const char* buff, size_t len, ssize_t* count)
+{
+	char str[5];
+	char* endp;
+	unsigned long val;
+
+	if (len < 4) {
+		strncpy(str, buff, len);
+		str[len+1] = '\0';
+	} else {
+		strncpy(str, buff, 4);
+		str[4] = '\0';
+	}
+
+	val = simple_strtoul(str, &endp, 0);
+
+	*count = 0;
+	if (val <= 0xff)
+		*count = (ssize_t)(endp - str);
+	if ((*count) && (len == *count+1) && (buff[*count] == '\n'))
+		*count += 1;
+
+	return (u8)val;
+}
+
+/*
+   NOTE 1: being inside one of the following methods implies that the v4l
+           device exists for sure (see kobjects and reference counters)
+   NOTE 2: buffers are PAGE_SIZE long
+*/
+
+static ssize_t et61x251_show_reg(struct class_device* cd, char* buf)
+{
+	struct et61x251_device* cam;
+	ssize_t count;
+
+	if (down_interruptible(&et61x251_sysfs_lock))
+		return -ERESTARTSYS;
+
+	cam = video_get_drvdata(to_video_device(cd));
+	if (!cam) {
+		up(&et61x251_sysfs_lock);
+		return -ENODEV;
+	}
+
+	count = sprintf(buf, "%u\n", cam->sysfs.reg);
+
+	up(&et61x251_sysfs_lock);
+
+	return count;
+}
+
+
+static ssize_t
+et61x251_store_reg(struct class_device* cd, const char* buf, size_t len)
+{
+	struct et61x251_device* cam;
+	u8 index;
+	ssize_t count;
+
+	if (down_interruptible(&et61x251_sysfs_lock))
+		return -ERESTARTSYS;
+
+	cam = video_get_drvdata(to_video_device(cd));
+	if (!cam) {
+		up(&et61x251_sysfs_lock);
+		return -ENODEV;
+	}
+
+	index = et61x251_strtou8(buf, len, &count);
+	if (index > 0x8e || !count) {
+		up(&et61x251_sysfs_lock);
+		return -EINVAL;
+	}
+
+	cam->sysfs.reg = index;
+
+	DBG(2, "Moved ET61X[12]51 register index to 0x%02X", cam->sysfs.reg);
+	DBG(3, "Written bytes: %zd", count);
+
+	up(&et61x251_sysfs_lock);
+
+	return count;
+}
+
+
+static ssize_t et61x251_show_val(struct class_device* cd, char* buf)
+{
+	struct et61x251_device* cam;
+	ssize_t count;
+	int val;
+
+	if (down_interruptible(&et61x251_sysfs_lock))
+		return -ERESTARTSYS;
+
+	cam = video_get_drvdata(to_video_device(cd));
+	if (!cam) {
+		up(&et61x251_sysfs_lock);
+		return -ENODEV;