drivers/media/video/gspca/sq905c.c - arm/linux-arm64-legacy - Git at Google

 /*
  * SQ905C subdriver
  *
  * Copyright (C) 2009 Theodore Kilgore
  *
  * 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
  * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */

 /*
  *
  * This driver uses work done in
  * libgphoto2/camlibs/digigr8, Copyright (C) Theodore Kilgore.
  *
  * This driver has also used as a base the sq905c driver
  * and may contain code fragments from it.
  */

 #define MODULE_NAME "sq905c"

 #include <linux/workqueue.h>
 #include <linux/slab.h>
 #include "gspca.h"

 MODULE_AUTHOR("Theodore Kilgore <kilgota@auburn.edu>");
 MODULE_DESCRIPTION("GSPCA/SQ905C USB Camera Driver");
 MODULE_LICENSE("GPL");

 /* Default timeouts, in ms */
 #define SQ905C_CMD_TIMEOUT 500
 #define SQ905C_DATA_TIMEOUT 1000

 /* Maximum transfer size to use. */
 #define SQ905C_MAX_TRANSFER 0x8000

 #define FRAME_HEADER_LEN 0x50

 /* Commands. These go in the "value" slot. */
 #define SQ905C_CLEAR   0xa0		/* clear everything */
 #define SQ905C_GET_ID  0x14f4		/* Read version number */
 #define SQ905C_CAPTURE_LOW 0xa040	/* Starts capture at 160x120 */
 #define SQ905C_CAPTURE_MED 0x1440	/* Starts capture at 320x240 */
 #define SQ905C_CAPTURE_HI 0x2840	/* Starts capture at 320x240 */

 /* For capture, this must go in the "index" slot. */
 #define SQ905C_CAPTURE_INDEX 0x110f

 /* Structure to hold all of our device specific stuff */
 struct sd {
 	struct gspca_dev gspca_dev;	/* !! must be the first item */
 	const struct v4l2_pix_format *cap_mode;
 	/* Driver stuff */
 	struct work_struct work_struct;
 	struct workqueue_struct *work_thread;
 };

 /*
  * Most of these cameras will do 640x480 and 320x240. 160x120 works
  * in theory but gives very poor output. Therefore, not supported.
  * The 0x2770:0x9050 cameras have max resolution of 320x240.
  */
 static struct v4l2_pix_format sq905c_mode[] = {
 	{ 320, 240, V4L2_PIX_FMT_SQ905C, V4L2_FIELD_NONE,
 		.bytesperline = 320,
 		.sizeimage = 320 * 240,
 		.colorspace = V4L2_COLORSPACE_SRGB,
 		.priv = 0},
 	{ 640, 480, V4L2_PIX_FMT_SQ905C, V4L2_FIELD_NONE,
 		.bytesperline = 640,
 		.sizeimage = 640 * 480,
 		.colorspace = V4L2_COLORSPACE_SRGB,
 		.priv = 0}
 };

 /* Send a command to the camera. */
 static int sq905c_command(struct gspca_dev *gspca_dev, u16 command, u16 index)
 {
 	int ret;

 	ret = usb_control_msg(gspca_dev->dev,
 			      usb_sndctrlpipe(gspca_dev->dev, 0),
 			      USB_REQ_SYNCH_FRAME,                /* request */
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			      command, index, NULL, 0,
 			      SQ905C_CMD_TIMEOUT);
 	if (ret < 0) {
 		PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)",
 			__func__, ret);
 		return ret;
 	}

 	return 0;
 }

 static int sq905c_read(struct gspca_dev *gspca_dev, u16 command, u16 index,
 		       int size)
 {
 	int ret;

 	ret = usb_control_msg(gspca_dev->dev,
 			      usb_rcvctrlpipe(gspca_dev->dev, 0),
 			      USB_REQ_SYNCH_FRAME,		/* request */
 			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			      command, index, gspca_dev->usb_buf, size,
 			      SQ905C_CMD_TIMEOUT);
 	if (ret < 0) {
 		PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)",
 		       __func__, ret);
 		return ret;
 	}

 	return 0;
 }

 /* This function is called as a workqueue function and runs whenever the camera
  * is streaming data. Because it is a workqueue function it is allowed to sleep
  * so we can use synchronous USB calls. To avoid possible collisions with other
  * threads attempting to use the camera's USB interface the gspca usb_lock is
  * used when performing the one USB control operation inside the workqueue,
  * which tells the camera to close the stream. In practice the only thing
  * which needs to be protected against is the usb_set_interface call that
  * gspca makes during stream_off. Otherwise the camera doesn't provide any
  * controls that the user could try to change.
  */
 static void sq905c_dostream(struct work_struct *work)
 {
 	struct sd *dev = container_of(work, struct sd, work_struct);
 	struct gspca_dev *gspca_dev = &dev->gspca_dev;
 	int bytes_left; /* bytes remaining in current frame. */
 	int data_len;   /* size to use for the next read. */
 	int act_len;
 	int packet_type;
 	int ret;
 	u8 *buffer;

 	buffer = kmalloc(SQ905C_MAX_TRANSFER, GFP_KERNEL | GFP_DMA);
 	if (!buffer) {
 		PDEBUG(D_ERR, "Couldn't allocate USB buffer");
 		goto quit_stream;
 	}

 	while (gspca_dev->present && gspca_dev->streaming) {
 		/* Request the header, which tells the size to download */
 		ret = usb_bulk_msg(gspca_dev->dev,
 				usb_rcvbulkpipe(gspca_dev->dev, 0x81),
 				buffer, FRAME_HEADER_LEN, &act_len,
 				SQ905C_DATA_TIMEOUT);
 		PDEBUG(D_STREAM,
 			"Got %d bytes out of %d for header",
 			act_len, FRAME_HEADER_LEN);
 		if (ret < 0 || act_len < FRAME_HEADER_LEN)
 			goto quit_stream;
 		/* size is read from 4 bytes starting 0x40, little endian */
 		bytes_left = buffer[0x40]|(buffer[0x41]<<8)|(buffer[0x42]<<16)
 					|(buffer[0x43]<<24);
 		PDEBUG(D_STREAM, "bytes_left = 0x%x", bytes_left);
 		/* We keep the header. It has other information, too. */
 		packet_type = FIRST_PACKET;
 		gspca_frame_add(gspca_dev, packet_type,
 				buffer, FRAME_HEADER_LEN);
 		while (bytes_left > 0 && gspca_dev->present) {
 			data_len = bytes_left > SQ905C_MAX_TRANSFER ?
 				SQ905C_MAX_TRANSFER : bytes_left;
 			ret = usb_bulk_msg(gspca_dev->dev,
 				usb_rcvbulkpipe(gspca_dev->dev, 0x81),
 				buffer, data_len, &act_len,
 				SQ905C_DATA_TIMEOUT);
 			if (ret < 0 || act_len < data_len)
 				goto quit_stream;
 			PDEBUG(D_STREAM,
 				"Got %d bytes out of %d for frame",
 				data_len, bytes_left);
 			bytes_left -= data_len;
 			if (bytes_left == 0)
 				packet_type = LAST_PACKET;
 			else
 				packet_type = INTER_PACKET;
 			gspca_frame_add(gspca_dev, packet_type,
 					buffer, data_len);
 		}
 	}
 quit_stream:
 	if (gspca_dev->present) {
 		mutex_lock(&gspca_dev->usb_lock);
 		sq905c_command(gspca_dev, SQ905C_CLEAR, 0);
 		mutex_unlock(&gspca_dev->usb_lock);
 	}
 	kfree(buffer);
 }

 /* This function is called at probe time just before sd_init */
 static int sd_config(struct gspca_dev *gspca_dev,
 		const struct usb_device_id *id)
 {
 	struct cam *cam = &gspca_dev->cam;
 	struct sd *dev = (struct sd *) gspca_dev;
 	int ret;

 	PDEBUG(D_PROBE,
 		"SQ9050 camera detected"
 		" (vid/pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);

 	ret = sq905c_command(gspca_dev, SQ905C_GET_ID, 0);
 	if (ret < 0) {
 		PDEBUG(D_ERR, "Get version command failed");
 		return ret;
 	}

 	ret = sq905c_read(gspca_dev, 0xf5, 0, 20);
 	if (ret < 0) {
 		PDEBUG(D_ERR, "Reading version command failed");
 		return ret;
 	}
 	/* Note we leave out the usb id and the manufacturing date */
 	PDEBUG(D_PROBE,
 	       "SQ9050 ID string: %02x - %02x %02x %02x %02x %02x %02x",
 		gspca_dev->usb_buf[3],
 		gspca_dev->usb_buf[14], gspca_dev->usb_buf[15],
 		gspca_dev->usb_buf[16], gspca_dev->usb_buf[17],
 		gspca_dev->usb_buf[18], gspca_dev->usb_buf[19]);

 	cam->cam_mode = sq905c_mode;
 	cam->nmodes = 2;
 	if (gspca_dev->usb_buf[15] == 0)
 		cam->nmodes = 1;
 	/* We don't use the buffer gspca allocates so make it small. */
 	cam->bulk_size = 32;
 	cam->bulk = 1;
 	INIT_WORK(&dev->work_struct, sq905c_dostream);
 	return 0;
 }

 /* called on streamoff with alt==0 and on disconnect */
 /* the usb_lock is held at entry - restore on exit */
 static void sd_stop0(struct gspca_dev *gspca_dev)
 {
 	struct sd *dev = (struct sd *) gspca_dev;

 	/* wait for the work queue to terminate */
 	mutex_unlock(&gspca_dev->usb_lock);
 	/* This waits for sq905c_dostream to finish */
 	destroy_workqueue(dev->work_thread);
 	dev->work_thread = NULL;
 	mutex_lock(&gspca_dev->usb_lock);
 }

 /* this function is called at probe and resume time */
 static int sd_init(struct gspca_dev *gspca_dev)
 {
 	int ret;

 	/* connect to the camera and reset it. */
 	ret = sq905c_command(gspca_dev, SQ905C_CLEAR, 0);
 	return ret;
 }

 /* Set up for getting frames. */
 static int sd_start(struct gspca_dev *gspca_dev)
 {
 	struct sd *dev = (struct sd *) gspca_dev;
 	int ret;

 	dev->cap_mode = gspca_dev->cam.cam_mode;
 	/* "Open the shutter" and set size, to start capture */
 	switch (gspca_dev->width) {
 	case 640:
 		PDEBUG(D_STREAM, "Start streaming at high resolution");
 		dev->cap_mode++;
 		ret = sq905c_command(gspca_dev, SQ905C_CAPTURE_HI,
 						SQ905C_CAPTURE_INDEX);
 		break;
 	default: /* 320 */
 	PDEBUG(D_STREAM, "Start streaming at medium resolution");
 		ret = sq905c_command(gspca_dev, SQ905C_CAPTURE_MED,
 						SQ905C_CAPTURE_INDEX);
 	}

 	if (ret < 0) {
 		PDEBUG(D_ERR, "Start streaming command failed");
 		return ret;
 	}
 	/* Start the workqueue function to do the streaming */
 	dev->work_thread = create_singlethread_workqueue(MODULE_NAME);
 	queue_work(dev->work_thread, &dev->work_struct);

 	return 0;
 }

 /* Table of supported USB devices */
 static const __devinitdata struct usb_device_id device_table[] = {
 	{USB_DEVICE(0x2770, 0x905c)},
 	{USB_DEVICE(0x2770, 0x9050)},
 	{USB_DEVICE(0x2770, 0x9052)},
 	{USB_DEVICE(0x2770, 0x913d)},
 	{}
 };

 MODULE_DEVICE_TABLE(usb, device_table);

 /* sub-driver description */
 static const struct sd_desc sd_desc = {
 	.name   = MODULE_NAME,
 	.config = sd_config,
 	.init   = sd_init,
 	.start  = sd_start,
 	.stop0  = sd_stop0,
 };

 /* -- device connect -- */
 static int sd_probe(struct usb_interface *intf,
 		const struct usb_device_id *id)
 {
 	return gspca_dev_probe(intf, id,
 			&sd_desc,
 			sizeof(struct sd),
 			THIS_MODULE);
 }

 static struct usb_driver sd_driver = {
 	.name       = MODULE_NAME,
 	.id_table   = device_table,
 	.probe      = sd_probe,
 	.disconnect = gspca_disconnect,
 #ifdef CONFIG_PM
 	.suspend = gspca_suspend,
 	.resume  = gspca_resume,
 #endif
 };

 /* -- module insert / remove -- */
 static int __init sd_mod_init(void)
 {
 	int ret;

 	ret = usb_register(&sd_driver);
 	if (ret < 0)
 		return ret;
 	PDEBUG(D_PROBE, "registered");
 	return 0;
 }

 static void __exit sd_mod_exit(void)
 {
 	usb_deregister(&sd_driver);
 	PDEBUG(D_PROBE, "deregistered");
 }

 module_init(sd_mod_init);
 module_exit(sd_mod_exit);
	/*
	* SQ905C subdriver
	*
	* Copyright (C) 2009 Theodore Kilgore
	*
	* 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
	* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	/*
	*
	* This driver uses work done in
	* libgphoto2/camlibs/digigr8, Copyright (C) Theodore Kilgore.
	*
	* This driver has also used as a base the sq905c driver
	* and may contain code fragments from it.
	*/

	#define MODULE_NAME "sq905c"

	#include <linux/workqueue.h>
	#include <linux/slab.h>
	#include "gspca.h"

	MODULE_AUTHOR("Theodore Kilgore <kilgota@auburn.edu>");
	MODULE_DESCRIPTION("GSPCA/SQ905C USB Camera Driver");
	MODULE_LICENSE("GPL");

	/* Default timeouts, in ms */
	#define SQ905C_CMD_TIMEOUT 500
	#define SQ905C_DATA_TIMEOUT 1000

	/* Maximum transfer size to use. */
	#define SQ905C_MAX_TRANSFER 0x8000

	#define FRAME_HEADER_LEN 0x50

	/* Commands. These go in the "value" slot. */
	#define SQ905C_CLEAR 0xa0 /* clear everything */
	#define SQ905C_GET_ID 0x14f4 /* Read version number */
	#define SQ905C_CAPTURE_LOW 0xa040 /* Starts capture at 160x120 */
	#define SQ905C_CAPTURE_MED 0x1440 /* Starts capture at 320x240 */
	#define SQ905C_CAPTURE_HI 0x2840 /* Starts capture at 320x240 */

	/* For capture, this must go in the "index" slot. */
	#define SQ905C_CAPTURE_INDEX 0x110f

	/* Structure to hold all of our device specific stuff */
	struct sd {
	struct gspca_dev gspca_dev; /* !! must be the first item */
	const struct v4l2_pix_format *cap_mode;
	/* Driver stuff */
	struct work_struct work_struct;
	struct workqueue_struct *work_thread;
	};

	/*
	* Most of these cameras will do 640x480 and 320x240. 160x120 works
	* in theory but gives very poor output. Therefore, not supported.
	* The 0x2770:0x9050 cameras have max resolution of 320x240.
	*/
	static struct v4l2_pix_format sq905c_mode[] = {
	{ 320, 240, V4L2_PIX_FMT_SQ905C, V4L2_FIELD_NONE,
	.bytesperline = 320,
	.sizeimage = 320 * 240,
	.colorspace = V4L2_COLORSPACE_SRGB,
	.priv = 0},
	{ 640, 480, V4L2_PIX_FMT_SQ905C, V4L2_FIELD_NONE,
	.bytesperline = 640,
	.sizeimage = 640 * 480,
	.colorspace = V4L2_COLORSPACE_SRGB,
	.priv = 0}
	};

	/* Send a command to the camera. */
	static int sq905c_command(struct gspca_dev *gspca_dev, u16 command, u16 index)
	{
	int ret;

	ret = usb_control_msg(gspca_dev->dev,
	usb_sndctrlpipe(gspca_dev->dev, 0),
	USB_REQ_SYNCH_FRAME, /* request */
	USB_DIR_OUT \| USB_TYPE_VENDOR \| USB_RECIP_DEVICE,
	command, index, NULL, 0,
	SQ905C_CMD_TIMEOUT);
	if (ret < 0) {
	PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)",
	__func__, ret);
	return ret;
	}

	return 0;
	}

	static int sq905c_read(struct gspca_dev *gspca_dev, u16 command, u16 index,
	int size)
	{
	int ret;

	ret = usb_control_msg(gspca_dev->dev,
	usb_rcvctrlpipe(gspca_dev->dev, 0),
	USB_REQ_SYNCH_FRAME, /* request */
	USB_DIR_IN \| USB_TYPE_VENDOR \| USB_RECIP_DEVICE,
	command, index, gspca_dev->usb_buf, size,
	SQ905C_CMD_TIMEOUT);
	if (ret < 0) {
	PDEBUG(D_ERR, "%s: usb_control_msg failed (%d)",
	__func__, ret);
	return ret;
	}

	return 0;
	}

	/* This function is called as a workqueue function and runs whenever the camera
	* is streaming data. Because it is a workqueue function it is allowed to sleep
	* so we can use synchronous USB calls. To avoid possible collisions with other
	* threads attempting to use the camera's USB interface the gspca usb_lock is
	* used when performing the one USB control operation inside the workqueue,
	* which tells the camera to close the stream. In practice the only thing
	* which needs to be protected against is the usb_set_interface call that
	* gspca makes during stream_off. Otherwise the camera doesn't provide any
	* controls that the user could try to change.
	*/
	static void sq905c_dostream(struct work_struct *work)
	{
	struct sd *dev = container_of(work, struct sd, work_struct);
	struct gspca_dev *gspca_dev = &dev->gspca_dev;
	int bytes_left; /* bytes remaining in current frame. */
	int data_len; /* size to use for the next read. */
	int act_len;
	int packet_type;
	int ret;
	u8 *buffer;

	buffer = kmalloc(SQ905C_MAX_TRANSFER, GFP_KERNEL \| GFP_DMA);
	if (!buffer) {
	PDEBUG(D_ERR, "Couldn't allocate USB buffer");
	goto quit_stream;
	}

	while (gspca_dev->present && gspca_dev->streaming) {
	/* Request the header, which tells the size to download */
	ret = usb_bulk_msg(gspca_dev->dev,
	usb_rcvbulkpipe(gspca_dev->dev, 0x81),
	buffer, FRAME_HEADER_LEN, &act_len,
	SQ905C_DATA_TIMEOUT);
	PDEBUG(D_STREAM,
	"Got %d bytes out of %d for header",
	act_len, FRAME_HEADER_LEN);
	if (ret < 0 \|\| act_len < FRAME_HEADER_LEN)
	goto quit_stream;
	/* size is read from 4 bytes starting 0x40, little endian */
	bytes_left = buffer[0x40]\|(buffer[0x41]<<8)\|(buffer[0x42]<<16)
	\|(buffer[0x43]<<24);
	PDEBUG(D_STREAM, "bytes_left = 0x%x", bytes_left);
	/* We keep the header. It has other information, too. */
	packet_type = FIRST_PACKET;
	gspca_frame_add(gspca_dev, packet_type,
	buffer, FRAME_HEADER_LEN);
	while (bytes_left > 0 && gspca_dev->present) {
	data_len = bytes_left > SQ905C_MAX_TRANSFER ?
	SQ905C_MAX_TRANSFER : bytes_left;
	ret = usb_bulk_msg(gspca_dev->dev,
	usb_rcvbulkpipe(gspca_dev->dev, 0x81),
	buffer, data_len, &act_len,
	SQ905C_DATA_TIMEOUT);
	if (ret < 0 \|\| act_len < data_len)
	goto quit_stream;
	PDEBUG(D_STREAM,
	"Got %d bytes out of %d for frame",
	data_len, bytes_left);
	bytes_left -= data_len;
	if (bytes_left == 0)
	packet_type = LAST_PACKET;
	else
	packet_type = INTER_PACKET;
	gspca_frame_add(gspca_dev, packet_type,
	buffer, data_len);
	}
	}
	quit_stream:
	if (gspca_dev->present) {
	mutex_lock(&gspca_dev->usb_lock);
	sq905c_command(gspca_dev, SQ905C_CLEAR, 0);
	mutex_unlock(&gspca_dev->usb_lock);
	}
	kfree(buffer);
	}

	/* This function is called at probe time just before sd_init */
	static int sd_config(struct gspca_dev *gspca_dev,
	const struct usb_device_id *id)
	{
	struct cam *cam = &gspca_dev->cam;
	struct sd dev = (struct sd ) gspca_dev;
	int ret;

	PDEBUG(D_PROBE,
	"SQ9050 camera detected"
	" (vid/pid 0x%04X:0x%04X)", id->idVendor, id->idProduct);

	ret = sq905c_command(gspca_dev, SQ905C_GET_ID, 0);
	if (ret < 0) {
	PDEBUG(D_ERR, "Get version command failed");
	return ret;
	}

	ret = sq905c_read(gspca_dev, 0xf5, 0, 20);
	if (ret < 0) {
	PDEBUG(D_ERR, "Reading version command failed");
	return ret;
	}
	/* Note we leave out the usb id and the manufacturing date */
	PDEBUG(D_PROBE,
	"SQ9050 ID string: %02x - %02x %02x %02x %02x %02x %02x",
	gspca_dev->usb_buf[3],
	gspca_dev->usb_buf[14], gspca_dev->usb_buf[15],
	gspca_dev->usb_buf[16], gspca_dev->usb_buf[17],
	gspca_dev->usb_buf[18], gspca_dev->usb_buf[19]);

	cam->cam_mode = sq905c_mode;
	cam->nmodes = 2;
	if (gspca_dev->usb_buf[15] == 0)
	cam->nmodes = 1;
	/* We don't use the buffer gspca allocates so make it small. */
	cam->bulk_size = 32;
	cam->bulk = 1;
	INIT_WORK(&dev->work_struct, sq905c_dostream);
	return 0;
	}

	/* called on streamoff with alt==0 and on disconnect */
	/* the usb_lock is held at entry - restore on exit */
	static void sd_stop0(struct gspca_dev *gspca_dev)
	{
	struct sd dev = (struct sd ) gspca_dev;

	/* wait for the work queue to terminate */
	mutex_unlock(&gspca_dev->usb_lock);
	/* This waits for sq905c_dostream to finish */
	destroy_workqueue(dev->work_thread);
	dev->work_thread = NULL;
	mutex_lock(&gspca_dev->usb_lock);
	}

	/* this function is called at probe and resume time */
	static int sd_init(struct gspca_dev *gspca_dev)
	{
	int ret;

	/* connect to the camera and reset it. */
	ret = sq905c_command(gspca_dev, SQ905C_CLEAR, 0);
	return ret;
	}

	/* Set up for getting frames. */
	static int sd_start(struct gspca_dev *gspca_dev)
	{
	struct sd dev = (struct sd ) gspca_dev;
	int ret;

	dev->cap_mode = gspca_dev->cam.cam_mode;
	/* "Open the shutter" and set size, to start capture */
	switch (gspca_dev->width) {
	case 640:
	PDEBUG(D_STREAM, "Start streaming at high resolution");
	dev->cap_mode++;
	ret = sq905c_command(gspca_dev, SQ905C_CAPTURE_HI,
	SQ905C_CAPTURE_INDEX);
	break;
	default: /* 320 */
	PDEBUG(D_STREAM, "Start streaming at medium resolution");
	ret = sq905c_command(gspca_dev, SQ905C_CAPTURE_MED,
	SQ905C_CAPTURE_INDEX);
	}

	if (ret < 0) {
	PDEBUG(D_ERR, "Start streaming command failed");
	return ret;
	}
	/* Start the workqueue function to do the streaming */
	dev->work_thread = create_singlethread_workqueue(MODULE_NAME);
	queue_work(dev->work_thread, &dev->work_struct);

	return 0;
	}

	/* Table of supported USB devices */
	static const __devinitdata struct usb_device_id device_table[] = {
	{USB_DEVICE(0x2770, 0x905c)},
	{USB_DEVICE(0x2770, 0x9050)},
	{USB_DEVICE(0x2770, 0x9052)},
	{USB_DEVICE(0x2770, 0x913d)},
	{}
	};

	MODULE_DEVICE_TABLE(usb, device_table);

	/* sub-driver description */
	static const struct sd_desc sd_desc = {
	.name = MODULE_NAME,
	.config = sd_config,
	.init = sd_init,
	.start = sd_start,
	.stop0 = sd_stop0,
	};

	/* -- device connect -- */
	static int sd_probe(struct usb_interface *intf,
	const struct usb_device_id *id)
	{
	return gspca_dev_probe(intf, id,
	&sd_desc,
	sizeof(struct sd),
	THIS_MODULE);
	}

	static struct usb_driver sd_driver = {
	.name = MODULE_NAME,
	.id_table = device_table,
	.probe = sd_probe,
	.disconnect = gspca_disconnect,
	#ifdef CONFIG_PM
	.suspend = gspca_suspend,
	.resume = gspca_resume,
	#endif
	};

	/* -- module insert / remove -- */
	static int __init sd_mod_init(void)
	{
	int ret;

	ret = usb_register(&sd_driver);
	if (ret < 0)
	return ret;
	PDEBUG(D_PROBE, "registered");
	return 0;
	}

	static void __exit sd_mod_exit(void)
	{
	usb_deregister(&sd_driver);
	PDEBUG(D_PROBE, "deregistered");
	}

	module_init(sd_mod_init);
	module_exit(sd_mod_exit);