text: /***************************************************************************
   * V4L2 driver for ET61X[12]51 PC Camera Controllers                       *
   *                                                                         *
   * Copyright (C) 2006-2007 by Luca Risolia <luca.risolia@studio.unibo.it>  *
   *                                                                         *
   * This program is free software; you can redistribute it and/or modify    *
   * it under the terms of the GNU General Public License as published by    *
   * the Free Software Foundation; either version 2 of the License, or       *
   * (at your option) any later version.                                     *
   *                                                                         *
   * This program is distributed in the hope that it will be useful,         *
   * but WITHOUT ANY WARRANTY; without even the implied warranty of          *
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
   * GNU General Public License for more details.                            *
   *                                                                         *
   * You should have received a copy of the GNU General Public License       *
   * along with this program; if not, write to the Free Software             *
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.               *
   ***************************************************************************/
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/param.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <linux/device.h>
  #include <linux/fs.h>
  #include <linux/delay.h>
  #include <linux/compiler.h>
  #include <linux/ioctl.h>
  #include <linux/poll.h>
  #include <linux/stat.h>
  #include <linux/mm.h>
  #include <linux/vmalloc.h>
  #include <linux/page-flags.h>
  #include <linux/byteorder/generic.h>
  #include <asm/page.h>
  #include <asm/uaccess.h>
  
  #include "et61x251.h"
  
  /*****************************************************************************/
  
  #define ET61X251_MODULE_NAME    "V4L2 driver for ET61X[12]51 "                \
  				"PC Camera Controllers"
  #define ET61X251_MODULE_AUTHOR  "(C) 2006-2007 Luca Risolia"
  #define ET61X251_AUTHOR_EMAIL   "<luca.risolia@studio.unibo.it>"
  #define ET61X251_MODULE_LICENSE "GPL"
  #define ET61X251_MODULE_VERSION "1:1.09"
  #define ET61X251_MODULE_VERSION_CODE  KERNEL_VERSION(1, 1, 9)
  
  /*****************************************************************************/
  
  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(ET61X251_FORCE_MUNMAP)"."
  		 "\n");
  
  static unsigned int frame_timeout[] = {[0 ... ET61X251_MAX_DEVICES-1] =
  				       ET61X251_FRAME_TIMEOUT};
  module_param_array(frame_timeout, uint, NULL, 0644);
  MODULE_PARM_DESC(frame_timeout,
  		 "\n<n[,...]> Timeout for a video frame in seconds."
  		 "\nThis parameter is specific for each detected camera."
  		 "\nDefault value is "
  		 __MODULE_STRING(ET61X251_FRAME_TIMEOUT)"."
  		 "\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_user(cam->nbuffers *
  					    PAGE_ALIGN(imagesize))))
  			break;
  		cam->nbuffers--;
  	}
  
  	for (i = 0; i < cam->nbuffers; i++) {
  		cam->frame[i].bufmem = buff + i*PAGE_ALIGN(imagesize);
  		cam->frame[i].buf.index = i;
  		cam->frame[i].buf.m.offset = i*PAGE_ALIGN(imagesize);
  		cam->frame[i].buf.length = imagesize;
  		cam->frame[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  		cam->frame[i].buf.sequence = 0;
  		cam->frame[i].buf.field = V4L2_FIELD_NONE;
  		cam->frame[i].buf.memory = V4L2_MEMORY_MMAP;
  		cam->frame[i].buf.flags = 0;
  	}
  
  	return cam->nbuffers;
  }
  
  
  static void 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,
  		  const 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,
  		      const 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,
  		       const 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;
  
  	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)
  {
  	return et61x251_i2c_try_read(cam, &cam->sensor, address);
  }
  
  
  int et61x251_i2c_write(struct et61x251_device* cam, u8 address, u8 value)
  {
  	return et61x251_i2c_try_write(cam, &cam->sensor, address, value);
  }
  
  /*****************************************************************************/
  
  static void et61x251_urb_complete(struct urb *urb)
  {
  	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(&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;
  	struct usb_host_interface* altsetting = usb_altnum_to_altsetting(
  						   usb_ifnum_to_if(udev, 0),
  						   ET61X251_ALTERNATE_SETTING);
  	const unsigned int psz = le16_to_cpu(altsetting->
  					     endpoint[0].desc.wMaxPacketSize);
  	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)
  {
  	long timeout;
  
  	cam->stream = STREAM_INTERRUPT;
  	timeout = 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 (cam->stream != STREAM_OFF) {
  		cam->state |= DEV_MISCONFIGURED;
  		DBG(1, "URB timeout reached. The camera is misconfigured. To "
  		       "use it, close and open /dev/video%d again.",
  		    cam->v4ldev->minor);
  		return -EIO;
  	}
  
  	return 0;
  }
  
  /*****************************************************************************/
  
  #ifdef CONFIG_VIDEO_ADV_DEBUG
  static 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] = '\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 device* cd,
  				 struct device_attribute *attr, char* buf)
  {
  	struct et61x251_device* cam;
  	ssize_t count;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	count = sprintf(buf, "%u\n", cam->sysfs.reg);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t
  et61x251_store_reg(struct device* cd,
  		   struct device_attribute *attr, const char* buf, size_t len)
  {
  	struct et61x251_device* cam;
  	u8 index;
  	ssize_t count;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	index = et61x251_strtou8(buf, len, &count);
  	if (index > 0x8e || !count) {
  		mutex_unlock(&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);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t et61x251_show_val(struct device* cd,
  				 struct device_attribute *attr, char* buf)
  {
  	struct et61x251_device* cam;
  	ssize_t count;
  	int val;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	if ((val = et61x251_read_reg(cam, cam->sysfs.reg)) < 0) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EIO;
  	}
  
  	count = sprintf(buf, "%d\n", val);
  
  	DBG(3, "Read bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t
  et61x251_store_val(struct device* cd, struct device_attribute *attr,
  		   const char* buf, size_t len)
  {
  	struct et61x251_device* cam;
  	u8 value;
  	ssize_t count;
  	int err;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	value = et61x251_strtou8(buf, len, &count);
  	if (!count) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EINVAL;
  	}
  
  	err = et61x251_write_reg(cam, value, cam->sysfs.reg);
  	if (err) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EIO;
  	}
  
  	DBG(2, "Written ET61X[12]51 reg. 0x%02X, val. 0x%02X",
  	    cam->sysfs.reg, value);
  	DBG(3, "Written bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t et61x251_show_i2c_reg(struct device* cd,
  				     struct device_attribute *attr, char* buf)
  {
  	struct et61x251_device* cam;
  	ssize_t count;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	count = sprintf(buf, "%u\n", cam->sysfs.i2c_reg);
  
  	DBG(3, "Read bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t
  et61x251_store_i2c_reg(struct device* cd, struct device_attribute *attr,
  		       const char* buf, size_t len)
  {
  	struct et61x251_device* cam;
  	u8 index;
  	ssize_t count;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	index = et61x251_strtou8(buf, len, &count);
  	if (!count) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EINVAL;
  	}
  
  	cam->sysfs.i2c_reg = index;
  
  	DBG(2, "Moved sensor register index to 0x%02X", cam->sysfs.i2c_reg);
  	DBG(3, "Written bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t et61x251_show_i2c_val(struct device* cd,
  				     struct device_attribute *attr, char* buf)
  {
  	struct et61x251_device* cam;
  	ssize_t count;
  	int val;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	if (!(cam->sensor.sysfs_ops & ET61X251_I2C_READ)) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENOSYS;
  	}
  
  	if ((val = et61x251_i2c_read(cam, cam->sysfs.i2c_reg)) < 0) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EIO;
  	}
  
  	count = sprintf(buf, "%d\n", val);
  
  	DBG(3, "Read bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static ssize_t
  et61x251_store_i2c_val(struct device* cd, struct device_attribute *attr,
  		       const char* buf, size_t len)
  {
  	struct et61x251_device* cam;
  	u8 value;
  	ssize_t count;
  	int err;
  
  	if (mutex_lock_interruptible(&et61x251_sysfs_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(to_video_device(cd));
  	if (!cam) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENODEV;
  	}
  
  	if (!(cam->sensor.sysfs_ops & ET61X251_I2C_READ)) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -ENOSYS;
  	}
  
  	value = et61x251_strtou8(buf, len, &count);
  	if (!count) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EINVAL;
  	}
  
  	err = et61x251_i2c_write(cam, cam->sysfs.i2c_reg, value);
  	if (err) {
  		mutex_unlock(&et61x251_sysfs_lock);
  		return -EIO;
  	}
  
  	DBG(2, "Written sensor reg. 0x%02X, val. 0x%02X",
  	    cam->sysfs.i2c_reg, value);
  	DBG(3, "Written bytes: %zd", count);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  
  	return count;
  }
  
  
  static DEVICE_ATTR(reg, S_IRUGO | S_IWUSR,
  		   et61x251_show_reg, et61x251_store_reg);
  static DEVICE_ATTR(val, S_IRUGO | S_IWUSR,
  		   et61x251_show_val, et61x251_store_val);
  static DEVICE_ATTR(i2c_reg, S_IRUGO | S_IWUSR,
  		   et61x251_show_i2c_reg, et61x251_store_i2c_reg);
  static DEVICE_ATTR(i2c_val, S_IRUGO | S_IWUSR,
  		   et61x251_show_i2c_val, et61x251_store_i2c_val);
  
  
  static int et61x251_create_sysfs(struct et61x251_device* cam)
  {
  	struct device *classdev = &(cam->v4ldev->class_dev);
  	int err = 0;
  
  	if ((err = device_create_file(classdev, &dev_attr_reg)))
  		goto err_out;
  	if ((err = device_create_file(classdev, &dev_attr_val)))
  		goto err_reg;
  
  	if (cam->sensor.sysfs_ops) {
  		if ((err = device_create_file(classdev, &dev_attr_i2c_reg)))
  			goto err_val;
  		if ((err = device_create_file(classdev, &dev_attr_i2c_val)))
  			goto err_i2c_reg;
  	}
  
  err_i2c_reg:
  	if (cam->sensor.sysfs_ops)
  		device_remove_file(classdev, &dev_attr_i2c_reg);
  err_val:
  	device_remove_file(classdev, &dev_attr_val);
  err_reg:
  	device_remove_file(classdev, &dev_attr_reg);
  err_out:
  	return err;
  }
  #endif /* CONFIG_VIDEO_ADV_DEBUG */
  
  /*****************************************************************************/
  
  static int
  et61x251_set_pix_format(struct et61x251_device* cam,
  			struct v4l2_pix_format* pix)
  {
  	int r, err = 0;
  
  	if ((r = et61x251_read_reg(cam, 0x12)) < 0)
  		err += r;
  	if (pix->pixelformat == V4L2_PIX_FMT_ET61X251)
  		err += et61x251_write_reg(cam, r & 0xfd, 0x12);
  	else
  		err += et61x251_write_reg(cam, r | 0x02, 0x12);
  
  	return err ? -EIO : 0;
  }
  
  
  static int
  et61x251_set_compression(struct et61x251_device* cam,
  			 struct v4l2_jpegcompression* compression)
  {
  	int r, err = 0;
  
  	if ((r = et61x251_read_reg(cam, 0x12)) < 0)
  		err += r;
  	if (compression->quality == 0)
  		err += et61x251_write_reg(cam, r & 0xfb, 0x12);
  	else
  		err += et61x251_write_reg(cam, r | 0x04, 0x12);
  
  	return err ? -EIO : 0;
  }
  
  
  static int et61x251_set_scale(struct et61x251_device* cam, u8 scale)
  {
  	int r = 0, err = 0;
  
  	r = et61x251_read_reg(cam, 0x12);
  	if (r < 0)
  		err += r;
  
  	if (scale == 1)
  		err += et61x251_write_reg(cam, r & ~0x01, 0x12);
  	else if (scale == 2)
  		err += et61x251_write_reg(cam, r | 0x01, 0x12);
  
  	if (err)
  		return -EIO;
  
  	PDBGG("Scaling factor: %u", scale);
  
  	return 0;
  }
  
  
  static int
  et61x251_set_crop(struct et61x251_device* cam, struct v4l2_rect* rect)
  {
  	struct et61x251_sensor* s = &cam->sensor;
  	u16 fmw_sx = (u16)(rect->left - s->cropcap.bounds.left +
  			   s->active_pixel.left),
  	    fmw_sy = (u16)(rect->top - s->cropcap.bounds.top +
  			   s->active_pixel.top),
  	    fmw_length = (u16)(rect->width),
  	    fmw_height = (u16)(rect->height);
  	int err = 0;
  
  	err += et61x251_write_reg(cam, fmw_sx & 0xff, 0x69);
  	err += et61x251_write_reg(cam, fmw_sy & 0xff, 0x6a);
  	err += et61x251_write_reg(cam, fmw_length & 0xff, 0x6b);
  	err += et61x251_write_reg(cam, fmw_height & 0xff, 0x6c);
  	err += et61x251_write_reg(cam, (fmw_sx >> 8) | ((fmw_sy & 0x300) >> 6)
  				       | ((fmw_length & 0x300) >> 4)
  				       | ((fmw_height & 0x300) >> 2), 0x6d);
  	if (err)
  		return -EIO;
  
  	PDBGG("fmw_sx, fmw_sy, fmw_length, fmw_height: %u %u %u %u",
  	      fmw_sx, fmw_sy, fmw_length, fmw_height);
  
  	return 0;
  }
  
  
  static int et61x251_init(struct et61x251_device* cam)
  {
  	struct et61x251_sensor* s = &cam->sensor;
  	struct v4l2_control ctrl;
  	struct v4l2_queryctrl *qctrl;
  	struct v4l2_rect* rect;
  	u8 i = 0;
  	int err = 0;
  
  	if (!(cam->state & DEV_INITIALIZED)) {
  		mutex_init(&cam->open_mutex);
  		init_waitqueue_head(&cam->wait_open);
  		qctrl = s->qctrl;
  		rect = &(s->cropcap.defrect);
  		cam->compression.quality = ET61X251_COMPRESSION_QUALITY;
  	} else { /* use current values */
  		qctrl = s->_qctrl;
  		rect = &(s->_rect);
  	}
  
  	err += et61x251_set_scale(cam, rect->width / s->pix_format.width);
  	err += et61x251_set_crop(cam, rect);
  	if (err)
  		return err;
  
  	if (s->init) {
  		err = s->init(cam);
  		if (err) {
  			DBG(3, "Sensor initialization failed");
  			return err;
  		}
  	}
  
  	err += et61x251_set_compression(cam, &cam->compression);
  	err += et61x251_set_pix_format(cam, &s->pix_format);
  	if (s->set_pix_format)
  		err += s->set_pix_format(cam, &s->pix_format);
  	if (err)
  		return err;
  
  	if (s->pix_format.pixelformat == V4L2_PIX_FMT_ET61X251)
  		DBG(3, "Compressed video format is active, quality %d",
  		    cam->compression.quality);
  	else
  		DBG(3, "Uncompressed video format is active");
  
  	if (s->set_crop)
  		if ((err = s->set_crop(cam, rect))) {
  			DBG(3, "set_crop() failed");
  			return err;
  		}
  
  	if (s->set_ctrl) {
  		for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
  			if (s->qctrl[i].id != 0 &&
  			    !(s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)) {
  				ctrl.id = s->qctrl[i].id;
  				ctrl.value = qctrl[i].default_value;
  				err = s->set_ctrl(cam, &ctrl);
  				if (err) {
  					DBG(3, "Set %s control failed",
  					    s->qctrl[i].name);
  					return err;
  				}
  				DBG(3, "Image sensor supports '%s' control",
  				    s->qctrl[i].name);
  			}
  	}
  
  	if (!(cam->state & DEV_INITIALIZED)) {
  		mutex_init(&cam->fileop_mutex);
  		spin_lock_init(&cam->queue_lock);
  		init_waitqueue_head(&cam->wait_frame);
  		init_waitqueue_head(&cam->wait_stream);
  		cam->nreadbuffers = 2;
  		memcpy(s->_qctrl, s->qctrl, sizeof(s->qctrl));
  		memcpy(&(s->_rect), &(s->cropcap.defrect),
  		       sizeof(struct v4l2_rect));
  		cam->state |= DEV_INITIALIZED;
  	}
  
  	DBG(2, "Initialization succeeded");
  	return 0;
  }
  
  /*****************************************************************************/
  
  static void et61x251_release_resources(struct kref *kref)
  {
  	struct et61x251_device *cam;
  
  	mutex_lock(&et61x251_sysfs_lock);
  
  	cam = container_of(kref, struct et61x251_device, kref);
  
  	DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
  	video_set_drvdata(cam->v4ldev, NULL);
  	video_unregister_device(cam->v4ldev);
  	usb_put_dev(cam->usbdev);
  	kfree(cam->control_buffer);
  	kfree(cam);
  
  	mutex_unlock(&et61x251_sysfs_lock);
  }
  
  
  static int et61x251_open(struct inode* inode, struct file* filp)
  {
  	struct et61x251_device* cam;
  	int err = 0;
  
  	if (!down_read_trylock(&et61x251_dev_lock))
  		return -ERESTARTSYS;
  
  	cam = video_get_drvdata(video_devdata(filp));
  
  	if (wait_for_completion_interruptible(&cam->probe)) {
  		up_read(&et61x251_dev_lock);
  		return -ERESTARTSYS;
  	}
  
  	kref_get(&cam->kref);
  
  	if (mutex_lock_interruptible(&cam->open_mutex)) {
  		kref_put(&cam->kref, et61x251_release_resources);
  		up_read(&et61x251_dev_lock);
  		return -ERESTARTSYS;
  	}
  
  	if (cam->state & DEV_DISCONNECTED) {
  		DBG(1, "Device not present");
  		err = -ENODEV;
  		goto out;
  	}
  
  	if (cam->users) {
  		DBG(2, "Device /dev/video%d is already in use",
  		       cam->v4ldev->minor);
  		DBG(3, "Simultaneous opens are not supported");
  		if ((filp->f_flags & O_NONBLOCK) ||
  		    (filp->f_flags & O_NDELAY)) {
  			err = -EWOULDBLOCK;
  			goto out;
  		}
  		DBG(2, "A blocking open() has been requested. Wait for the "
  		       "device to be released...");
  		up_read(&et61x251_dev_lock);
  		err = wait_event_interruptible_exclusive(cam->wait_open,
  						(cam->state & DEV_DISCONNECTED)
  							 || !cam->users);
  		down_read(&et61x251_dev_lock);
  		if (err)
  			goto out;
  		if (cam->state & DEV_DISCONNECTED) {
  			err = -ENODEV;
  			goto out;
  		}
  	}
  
  	if (cam->state & DEV_MISCONFIGURED) {
  		err = et61x251_init(cam);
  		if (err) {
  			DBG(1, "Initialization failed again. "
  			       "I will retry on next open().");
  			goto out;
  		}
  		cam->state &= ~DEV_MISCONFIGURED;
  	}
  
  	if ((err = et61x251_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;
  	et61x251_empty_framequeues(cam);
  
  	DBG(3, "Video device /dev/video%d is open", cam->v4ldev->minor);
  
  out:
  	mutex_unlock(&cam->open_mutex);
  	if (err)
  		kref_put(&cam->kref, et61x251_release_resources);
  	up_read(&et61x251_dev_lock);
  	return err;
  }
  
  
  static int et61x251_release(struct inode* inode, struct file* filp)
  {
  	struct et61x251_device* cam;
  
  	down_write(&et61x251_dev_lock);
  
  	cam = video_get_drvdata(video_devdata(filp));
  
  	et61x251_stop_transfer(cam);
  	et61x251_release_buffers(cam);
  	cam->users--;
  	wake_up_interruptible_nr(&cam->wait_open, 1);
  
  	DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);
  
  	kref_put(&cam->kref, et61x251_release_resources);
  
  	up_write(&et61x251_dev_lock);
  
  	return 0;
  }
  
  
  static ssize_t
  et61x251_read(struct file* filp, char __user * buf,
  	      size_t count, loff_t* f_pos)
  {
  	struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
  	struct et61x251_frame_t* f, * i;
  	unsigned long lock_flags;
  	long timeout;
  	int err = 0;
  
  	if (mutex_lock_interruptible(&cam->fileop_mutex))
  		return -ERESTARTSYS;
  
  	if (cam->state & DEV_DISCONNECTED) {
  		DBG(1, "Device not present");
  		mutex_unlock(&cam->fileop_mutex);
  		return -ENODEV;
  	}
  
  	if (cam->state & DEV_MISCONFIGURED) {
  		DBG(1, "The camera is misconfigured. Close and open it "
  		       "again.");
  		mutex_unlock(&cam->fileop_mutex);
  		return -EIO;
  	}
  
  	if (cam->io == IO_MMAP) {
  		DBG(3, "Close and open the device again to choose the read "
  		       "method");
  		mutex_unlock(&cam->fileop_mutex);
  		return -EBUSY;
  	}
  
  	if (cam->io == IO_NONE) {
  		if (!et61x251_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))
  			et61x251_empty_framequeues(cam);
  		et61x251_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),
  			    cam->module_param.frame_timeout *
  			    1000 * msecs_to_jiffies(1) );
  		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 et61x251_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);
  
  	et61x251_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 et61x251_poll(struct file *filp, poll_table *wait)
  {
  	struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
  	struct et61x251_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 (!et61x251_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);
  		et61x251_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 et61x251_vm_open(struct vm_area_struct* vma)
  {
  	struct et61x251_frame_t* f = vma->vm_private_data;
  	f->vma_use_count++;
  }
  
  
  static void et61x251_vm_close(struct vm_area_struct* vma)
  {
  	/* NOTE: buffers are not freed here */
  	struct et61x251_frame_t* f = vma->vm_private_data;
  	f->vma_use_count--;
  }
  
  
  static struct vm_operations_struct et61x251_vm_ops = {
  	.open = et61x251_vm_open,
  	.close = et61x251_vm_close,
  };
  
  
  static int et61x251_mmap(struct file* filp, struct vm_area_struct *vma)
  {
  	struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
  	unsigned long size = vma->vm_end - vma->vm_start,
  		      start = vma->vm_start;
  	void *pos;
  	u32 i;
  
  	if (mutex_lock_interruptible(&cam->fileop_mutex))
  		return -ERESTARTSYS;
  
  	if (cam->state & DEV_DISCONNECTED) {
  		DBG(1, "Device not present");
  		mutex_unlock(&cam->fileop_mutex);
  		return -ENODEV;
  	}
  
  	if (cam->state & DEV_MISCONFIGURED) {
  		DBG(1, "The camera is misconfigured. Close and open it "
  		       "again.");
  		mutex_unlock(&cam->fileop_mutex);
  		return -EIO;
  	}
  
  	if (!(vma->vm_flags & (VM_WRITE | VM_READ))) {
  		mutex_unlock(&cam->fileop_mutex);
  		return -EACCES;
  	}
  
  	if (cam->io != IO_MMAP ||
  	    size != PAGE_ALIGN(cam->frame[0].buf.length)) {
  		mutex_unlock(&cam->fileop_mutex);
  		return -EINVAL;
  	}
  
  	for (i = 0; i < cam->nbuffers; i++) {
  		if ((cam->frame[i].buf.m.offset>>PAGE_SHIFT) == vma->vm_pgoff)
  			break;
  	}
  	if (i == cam->nbuffers) {
  		mutex_unlock(&cam->fileop_mutex);
  		return -EINVAL;
  	}
  
  	vma->vm_flags |= VM_IO;
  	vma->vm_flags |= VM_RESERVED;
  
  	pos = cam->frame[i].bufmem;
  	while (size > 0) { /* size is page-aligned */
  		if (vm_insert_page(vma, start, vmalloc_to_page(pos))) {
  			mutex_unlock(&cam->fileop_mutex);
  			return -EAGAIN;
  		}
  		start += PAGE_SIZE;
  		pos += PAGE_SIZE;
  		size -= PAGE_SIZE;
  	}
  
  	vma->vm_ops = &et61x251_vm_ops;
  	vma->vm_private_data = &cam->frame[i];
  	et61x251_vm_open(vma);
  
  	mutex_unlock(&cam->fileop_mutex);
  
  	return 0;
  }
  
  /*****************************************************************************/
  
  static int
  et61x251_vidioc_querycap(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_capability cap = {
  		.driver = "et61x251",
  		.version = ET61X251_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
  et61x251_vidioc_enuminput(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_input i;
  
  	if (copy_from_user(&i, arg, sizeof(i)))
  		return -EFAULT;
  
  	if (i.index)
  		return -EINVAL;
  
  	memset(&i, 0, sizeof(i));
  	strcpy(i.name, "Camera");
  	i.type = V4L2_INPUT_TYPE_CAMERA;
  
  	if (copy_to_user(arg, &i, sizeof(i)))
  		return -EFAULT;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_g_input(struct et61x251_device* cam, void __user * arg)
  {
  	int index = 0;
  
  	if (copy_to_user(arg, &index, sizeof(index)))
  		return -EFAULT;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_s_input(struct et61x251_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
  et61x251_vidioc_query_ctrl(struct et61x251_device* cam, void __user * arg)
  {
  	struct et61x251_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
  et61x251_vidioc_g_ctrl(struct et61x251_device* cam, void __user * arg)
  {
  	struct et61x251_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
  et61x251_vidioc_s_ctrl(struct et61x251_device* cam, void __user * arg)
  {
  	struct et61x251_sensor* s = &cam->sensor;
  	struct v4l2_control ctrl;
  	u8 i;
  	int err = 0;
  
  	if (!s->set_ctrl)
  		return -EINVAL;
  
  	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
  		return -EFAULT;
  
  	for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
  		if (ctrl.id == s->qctrl[i].id) {
  			if (s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)
  				return -EINVAL;
  			if (ctrl.value < s->qctrl[i].minimum ||
  			    ctrl.value > s->qctrl[i].maximum)
  				return -ERANGE;
  			ctrl.value -= ctrl.value % s->qctrl[i].step;
  			break;
  		}
  
  	if ((err = s->set_ctrl(cam, &ctrl)))
  		return err;
  
  	s->_qctrl[i].default_value = ctrl.value;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_cropcap(struct et61x251_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
  et61x251_vidioc_g_crop(struct et61x251_device* cam, void __user * arg)
  {
  	struct et61x251_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
  et61x251_vidioc_s_crop(struct et61x251_device* cam, void __user * arg)
  {
  	struct et61x251_sensor* s = &cam->sensor;
  	struct v4l2_crop crop;
  	struct v4l2_rect* rect;
  	struct v4l2_rect* bounds = &(s->cropcap.bounds);
  	struct v4l2_pix_format* pix_format = &(s->pix_format);
  	u8 scale;
  	const enum et61x251_stream_state stream = cam->stream;
  	const u32 nbuffers = cam->nbuffers;
  	u32 i;
  	int err = 0;
  
  	if (copy_from_user(&crop, arg, sizeof(crop)))
  		return -EFAULT;
  
  	rect = &(crop.c);
  
  	if (crop.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		return -EINVAL;
  
  	if (cam->module_param.force_munmap)
  		for (i = 0; i < cam->nbuffers; i++)
  			if (cam->frame[i].vma_use_count) {
  				DBG(3, "VIDIOC_S_CROP failed. "
  				       "Unmap the buffers first.");
  				return -EBUSY;
  			}
  
  	/* Preserve R,G or B origin */
  	rect->left = (s->_rect.left & 1L) ? rect->left | 1L : rect->left & ~1L;
  	rect->top = (s->_rect.top & 1L) ? rect->top | 1L : rect->top & ~1L;
  
  	if (rect->width < 16)
  		rect->width = 16;
  	if (rect->height < 16)
  		rect->height = 16;
  	if (rect->width > bounds->width)
  		rect->width = bounds->width;
  	if (rect->height > bounds->height)
  		rect->height = bounds->height;
  	if (rect->left < bounds->left)
  		rect->left = bounds->left;
  	if (rect->top < bounds->top)
  		rect->top = bounds->top;
  	if (rect->left + rect->width > bounds->left + bounds->width)
  		rect->left = bounds->left+bounds->width - rect->width;
  	if (rect->top + rect->height > bounds->top + bounds->height)
  		rect->top = bounds->top+bounds->height - rect->height;
  
  	rect->width &= ~15L;
  	rect->height &= ~15L;
  
  	if (ET61X251_PRESERVE_IMGSCALE) {
  		/* Calculate the actual scaling factor */
  		u32 a, b;
  		a = rect->width * rect->height;
  		b = pix_format->width * pix_format->height;
  		scale = b ? (u8)((a / b) < 4 ? 1 : 2) : 1;
  	} else
  		scale = 1;
  
  	if (cam->stream == STREAM_ON)
  		if ((err = et61x251_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)
  		et61x251_release_buffers(cam);
  
  	err = et61x251_set_crop(cam, rect);
  	if (s->set_crop)
  		err += s->set_crop(cam, rect);
  	err += et61x251_set_scale(cam, scale);
  
  	if (err) { /* atomic, no rollback in ioctl() */
  		cam->state |= DEV_MISCONFIGURED;
  		DBG(1, "VIDIOC_S_CROP failed because of hardware problems. To "
  		       "use the camera, close and open /dev/video%d again.",
  		    cam->v4ldev->minor);
  		return -EIO;
  	}
  
  	s->pix_format.width = rect->width/scale;
  	s->pix_format.height = rect->height/scale;
  	memcpy(&(s->_rect), rect, sizeof(*rect));
  
  	if ((cam->module_param.force_munmap  || cam->io == IO_READ) &&
  	    nbuffers != et61x251_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)
  		et61x251_empty_framequeues(cam);
  	else if (cam->module_param.force_munmap)
  		et61x251_requeue_outqueue(cam);
  
  	cam->stream = stream;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_enum_framesizes(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_frmsizeenum frmsize;
  
  	if (copy_from_user(&frmsize, arg, sizeof(frmsize)))
  		return -EFAULT;
  
  	if (frmsize.index != 0)
  		return -EINVAL;
  
  	if (frmsize.pixel_format != V4L2_PIX_FMT_ET61X251 &&
  	    frmsize.pixel_format != V4L2_PIX_FMT_SBGGR8)
  		return -EINVAL;
  
  	frmsize.type = V4L2_FRMSIZE_TYPE_STEPWISE;
  	frmsize.stepwise.min_width = frmsize.stepwise.step_width = 16;
  	frmsize.stepwise.min_height = frmsize.stepwise.step_height = 16;
  	frmsize.stepwise.max_width = cam->sensor.cropcap.bounds.width;
  	frmsize.stepwise.max_height = cam->sensor.cropcap.bounds.height;
  	memset(&frmsize.reserved, 0, sizeof(frmsize.reserved));
  
  	if (copy_to_user(arg, &frmsize, sizeof(frmsize)))
  		return -EFAULT;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_enum_fmt(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_fmtdesc fmtd;
  
  	if (copy_from_user(&fmtd, arg, sizeof(fmtd)))
  		return -EFAULT;
  
  	if (fmtd.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		return -EINVAL;
  
  	if (fmtd.index == 0) {
  		strcpy(fmtd.description, "bayer rgb");
  		fmtd.pixelformat = V4L2_PIX_FMT_SBGGR8;
  	} else if (fmtd.index == 1) {
  		strcpy(fmtd.description, "compressed");
  		fmtd.pixelformat = V4L2_PIX_FMT_ET61X251;
  		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
  et61x251_vidioc_g_fmt(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_format format;
  	struct v4l2_pix_format* pfmt = &(cam->sensor.pix_format);
  
  	if (copy_from_user(&format, arg, sizeof(format)))
  		return -EFAULT;
  
  	if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		return -EINVAL;
  
  	pfmt->colorspace = (pfmt->pixelformat == V4L2_PIX_FMT_ET61X251) ?
  			   0 : V4L2_COLORSPACE_SRGB;
  	pfmt->bytesperline = (pfmt->pixelformat==V4L2_PIX_FMT_ET61X251)
  			     ? 0 : (pfmt->width * pfmt->priv) / 8;
  	pfmt->sizeimage = pfmt->height * ((pfmt->width*pfmt->priv)/8);
  	pfmt->field = V4L2_FIELD_NONE;
  	memcpy(&(format.fmt.pix), pfmt, sizeof(*pfmt));
  
  	if (copy_to_user(arg, &format, sizeof(format)))
  		return -EFAULT;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_try_s_fmt(struct et61x251_device* cam, unsigned int cmd,
  			  void __user * arg)
  {
  	struct et61x251_sensor* s = &cam->sensor;
  	struct v4l2_format format;
  	struct v4l2_pix_format* pix;
  	struct v4l2_pix_format* pfmt = &(s->pix_format);
  	struct v4l2_rect* bounds = &(s->cropcap.bounds);
  	struct v4l2_rect rect;
  	u8 scale;
  	const enum et61x251_stream_state stream = cam->stream;
  	const u32 nbuffers = cam->nbuffers;
  	u32 i;
  	int err = 0;
  
  	if (copy_from_user(&format, arg, sizeof(format)))
  		return -EFAULT;
  
  	pix = &(format.fmt.pix);
  
  	if (format.type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
  		return -EINVAL;
  
  	memcpy(&rect, &(s->_rect), sizeof(rect));
  
  	{ /* calculate the actual scaling factor */
  		u32 a, b;
  		a = rect.width * rect.height;
  		b = pix->width * pix->height;
  		scale = b ? (u8)((a / b) < 4 ? 1 : 2) : 1;
  	}
  
  	rect.width = scale * pix->width;
  	rect.height = scale * pix->height;
  
  	if (rect.width < 16)
  		rect.width = 16;
  	if (rect.height < 16)
  		rect.height = 16;
  	if (rect.width > bounds->left + bounds->width - rect.left)
  		rect.width = bounds->left + bounds->width - rect.left;
  	if (rect.height > bounds->top + bounds->height - rect.top)
  		rect.height = bounds->top + bounds->height - rect.top;
  
  	rect.width &= ~15L;
  	rect.height &= ~15L;
  
  	{ /* adjust the scaling factor */
  		u32 a, b;
  		a = rect.width * rect.height;
  		b = pix->width * pix->height;
  		scale = b ? (u8)((a / b) < 4 ? 1 : 2) : 1;
  	}
  
  	pix->width = rect.width / scale;
  	pix->height = rect.height / scale;
  
  	if (pix->pixelformat != V4L2_PIX_FMT_ET61X251 &&
  	    pix->pixelformat != V4L2_PIX_FMT_SBGGR8)
  		pix->pixelformat = pfmt->pixelformat;
  	pix->priv = pfmt->priv; /* bpp */
  	pix->colorspace = (pix->pixelformat == V4L2_PIX_FMT_ET61X251) ?
  			  0 : V4L2_COLORSPACE_SRGB;
  	pix->colorspace = pfmt->colorspace;
  	pix->bytesperline = (pix->pixelformat == V4L2_PIX_FMT_ET61X251)
  			    ? 0 : (pix->width * pix->priv) / 8;
  	pix->sizeimage = pix->height * ((pix->width * pix->priv) / 8);
  	pix->field = V4L2_FIELD_NONE;
  
  	if (cmd == VIDIOC_TRY_FMT) {
  		if (copy_to_user(arg, &format, sizeof(format)))
  			return -EFAULT;
  		return 0;
  	}
  
  	if (cam->module_param.force_munmap)
  		for (i = 0; i < cam->nbuffers; i++)
  			if (cam->frame[i].vma_use_count) {
  				DBG(3, "VIDIOC_S_FMT failed. "
  				       "Unmap the buffers first.");
  				return -EBUSY;
  			}
  
  	if (cam->stream == STREAM_ON)
  		if ((err = et61x251_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)
  		et61x251_release_buffers(cam);
  
  	err += et61x251_set_pix_format(cam, pix);
  	err += et61x251_set_crop(cam, &rect);
  	if (s->set_pix_format)
  		err += s->set_pix_format(cam, pix);
  	if (s->set_crop)
  		err += s->set_crop(cam, &rect);
  	err += et61x251_set_scale(cam, scale);
  
  	if (err) { /* atomic, no rollback in ioctl() */
  		cam->state |= DEV_MISCONFIGURED;
  		DBG(1, "VIDIOC_S_FMT failed because of hardware problems. To "
  		       "use the camera, close and open /dev/video%d again.",
  		    cam->v4ldev->minor);
  		return -EIO;
  	}
  
  	memcpy(pfmt, pix, sizeof(*pix));
  	memcpy(&(s->_rect), &rect, sizeof(rect));
  
  	if ((cam->module_param.force_munmap  || cam->io == IO_READ) &&
  	    nbuffers != et61x251_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)
  		et61x251_empty_framequeues(cam);
  	else if (cam->module_param.force_munmap)
  		et61x251_requeue_outqueue(cam);
  
  	cam->stream = stream;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_g_jpegcomp(struct et61x251_device* cam, void __user * arg)
  {
  	if (copy_to_user(arg, &cam->compression,
  			 sizeof(cam->compression)))
  		return -EFAULT;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_s_jpegcomp(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_jpegcompression jc;
  	const enum et61x251_stream_state stream = cam->stream;
  	int err = 0;
  
  	if (copy_from_user(&jc, arg, sizeof(jc)))
  		return -EFAULT;
  
  	if (jc.quality != 0 && jc.quality != 1)
  		return -EINVAL;
  
  	if (cam->stream == STREAM_ON)
  		if ((err = et61x251_stream_interrupt(cam)))
  			return err;
  
  	err += et61x251_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
  et61x251_vidioc_reqbufs(struct et61x251_device* cam, void __user * arg)
  {
  	struct v4l2_requestbuffers rb;
  	u32 i;
  	int err;
  
  	if (copy_from_user(&rb, arg, sizeof(rb)))
  		return -EFAULT;
  
  	if (rb.type != V4L2_BUF_TYPE_VIDEO_CAPTURE ||
  	    rb.memory != V4L2_MEMORY_MMAP)
  		return -EINVAL;
  
  	if (cam->io == IO_READ) {
  		DBG(3, "Close and open the device again to choose the mmap "
  		       "I/O method");
  		return -EBUSY;
  	}
  
  	for (i = 0; i < cam->nbuffers; i++)
  		if (cam->frame[i].vma_use_count) {
  			DBG(3, "VIDIOC_REQBUFS failed. "
  			       "Previous buffers are still mapped.");
  			return -EBUSY;
  		}
  
  	if (cam->stream == STREAM_ON)
  		if ((err = et61x251_stream_interrupt(cam)))
  			return err;
  
  	et61x251_empty_framequeues(cam);
  
  	et61x251_release_buffers(cam);
  	if (rb.count)
  		rb.count = et61x251_request_buffers(cam, rb.count, IO_MMAP);
  
  	if (copy_to_user(arg, &rb, sizeof(rb))) {
  		et61x251_release_buffers(cam);
  		cam->io = IO_NONE;
  		return -EFAULT;
  	}
  
  	cam->io = rb.count ? IO_MMAP : IO_NONE;
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_querybuf(struct et61x251_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
  et61x251_vidioc_qbuf(struct et61x251_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
  et61x251_vidioc_dqbuf(struct et61x251_device* cam, struct file* filp,
  		      void __user * arg)
  {
  	struct v4l2_buffer b;
  	struct et61x251_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),
  			    cam->module_param.frame_timeout *
  			    1000 * msecs_to_jiffies(1) );
  		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 et61x251_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
  et61x251_vidioc_streamon(struct et61x251_device* cam, void __user * arg)
  {
  	int type;
  
  	if (copy_from_user(&type, arg, sizeof(type)))
  		return -EFAULT;
  
  	if (type != V4L2_BUF_TYPE_VIDEO_CAPTURE || cam->io != IO_MMAP)
  		return -EINVAL;
  
  	cam->stream = STREAM_ON;
  
  	DBG(3, "Stream on");
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_streamoff(struct et61x251_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 = et61x251_stream_interrupt(cam)))
  			return err;
  
  	et61x251_empty_framequeues(cam);
  
  	DBG(3, "Stream off");
  
  	return 0;
  }
  
  
  static int
  et61x251_vidioc_g_parm(struct et61x251_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
  et61x251_vidioc_s_parm(struct et61x251_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 > ET61X251_MAX_FRAMES)
  		sp.parm.capture.readbuffers = ET61X251_MAX_FRAMES;
  
  	if (copy_to_user(arg, &sp, sizeof(sp)))
  		return -EFAULT;
  
  	cam->nreadbuffers = sp.parm.capture.readbuffers;
  
  	return 0;
  }
  
  
  static int et61x251_ioctl_v4l2(struct inode* inode, struct file* filp,
  			       unsigned int cmd, void __user * arg)
  {
  	struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
  
  	switch (cmd) {
  
  	case VIDIOC_QUERYCAP:
  		return et61x251_vidioc_querycap(cam, arg);
  
  	case VIDIOC_ENUMINPUT:
  		return et61x251_vidioc_enuminput(cam, arg);
  
  	case VIDIOC_G_INPUT:
  		return et61x251_vidioc_g_input(cam, arg);
  
  	case VIDIOC_S_INPUT:
  		return et61x251_vidioc_s_input(cam, arg);
  
  	case VIDIOC_QUERYCTRL:
  		return et61x251_vidioc_query_ctrl(cam, arg);
  
  	case VIDIOC_G_CTRL:
  		return et61x251_vidioc_g_ctrl(cam, arg);
  
  	case VIDIOC_S_CTRL:
  		return et61x251_vidioc_s_ctrl(cam, arg);
  
  	case VIDIOC_CROPCAP:
  		return et61x251_vidioc_cropcap(cam, arg);
  
  	case VIDIOC_G_CROP:
  		return et61x251_vidioc_g_crop(cam, arg);
  
  	case VIDIOC_S_CROP:
  		return et61x251_vidioc_s_crop(cam, arg);
  
  	case VIDIOC_ENUM_FMT:
  		return et61x251_vidioc_enum_fmt(cam, arg);
  
  	case VIDIOC_G_FMT:
  		return et61x251_vidioc_g_fmt(cam, arg);
  
  	case VIDIOC_TRY_FMT:
  	case VIDIOC_S_FMT:
  		return et61x251_vidioc_try_s_fmt(cam, cmd, arg);
  
  	case VIDIOC_ENUM_FRAMESIZES:
  		return et61x251_vidioc_enum_framesizes(cam, arg);
  
  	case VIDIOC_G_JPEGCOMP:
  		return et61x251_vidioc_g_jpegcomp(cam, arg);
  
  	case VIDIOC_S_JPEGCOMP:
  		return et61x251_vidioc_s_jpegcomp(cam, arg);
  
  	case VIDIOC_REQBUFS:
  		return et61x251_vidioc_reqbufs(cam, arg);
  
  	case VIDIOC_QUERYBUF:
  		return et61x251_vidioc_querybuf(cam, arg);
  
  	case VIDIOC_QBUF:
  		return et61x251_vidioc_qbuf(cam, arg);
  
  	case VIDIOC_DQBUF:
  		return et61x251_vidioc_dqbuf(cam, filp, arg);
  
  	case VIDIOC_STREAMON:
  		return et61x251_vidioc_streamon(cam, arg);
  
  	case VIDIOC_STREAMOFF:
  		return et61x251_vidioc_streamoff(cam, arg);
  
  	case VIDIOC_G_PARM:
  		return et61x251_vidioc_g_parm(cam, arg);
  
  	case VIDIOC_S_PARM:
  		return et61x251_vidioc_s_parm(cam, arg);
  
  	case VIDIOC_G_STD:
  	case VIDIOC_S_STD:
  	case VIDIOC_QUERYSTD:
  	case VIDIOC_ENUMSTD:
  	case VIDIOC_QUERYMENU:
  	case VIDIOC_ENUM_FRAMEINTERVALS:
  		return -EINVAL;
  
  	default:
  		return -EINVAL;
  
  	}
  }
  
  
  static int et61x251_ioctl(struct inode* inode, struct file* filp,
  			 unsigned int cmd, unsigned long arg)
  {
  	struct et61x251_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, "et61x251", cmd);
  
  	err = et61x251_ioctl_v4l2(inode, filp, cmd, (void __user *)arg);
  
  	mutex_unlock(&cam->fileop_mutex);
  
  	return err;
  }
  
  
  static const struct file_operations et61x251_fops = {
  	.owner = THIS_MODULE,
  	.open =    et61x251_open,
  	.release = et61x251_release,
  	.ioctl =   et61x251_ioctl,
  	.compat_ioctl = v4l_compat_ioctl32,
  	.read =    et61x251_read,
  	.poll =    et61x251_poll,
  	.mmap =    et61x251_mmap,
  	.llseek =  no_llseek,
  };
  
  /*****************************************************************************/
  
  /* It exists a single interface only. We do not need to validate anything. */
  static int
  et61x251_usb_probe(struct usb_interface* intf, const struct usb_device_id* id)
  {
  	struct usb_device *udev = interface_to_usbdev(intf);
  	struct et61x251_device* cam;
  	static unsigned int dev_nr = 0;
  	unsigned int i;
  	int err = 0;
  
  	if (!(cam = kzalloc(sizeof(struct et61x251_device), GFP_KERNEL)))
  		return -ENOMEM;
  
  	cam->usbdev = udev;
  
  	if (!(cam->control_buffer = kzalloc(8, 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;
  	}
  
  	DBG(2, "ET61X[12]51 PC Camera Controller detected "
  	       "(vid/pid 0x%04X:0x%04X)",id->idVendor, id->idProduct);
  
  	for  (i = 0; et61x251_sensor_table[i]; i++) {
  		err = et61x251_sensor_table[i](cam);
  		if (!err)
  			break;
  	}
  
  	if (!err)
  		DBG(2, "%s image sensor detected", cam->sensor.name);
  	else {
  		DBG(1, "No supported image sensor detected");
  		err = -ENODEV;
  		goto fail;
  	}
  
  	if (et61x251_init(cam)) {
  		DBG(1, "Initialization failed. I will retry on open().");
  		cam->state |= DEV_MISCONFIGURED;
  	}
  
  	strcpy(cam->v4ldev->name, "ET61X[12]51 PC Camera");
  	cam->v4ldev->owner = THIS_MODULE;
  	cam->v4ldev->type = VID_TYPE_CAPTURE | VID_TYPE_SCALES;
  	cam->v4ldev->fops = &et61x251_fops;
  	cam->v4ldev->minor = video_nr[dev_nr];
  	cam->v4ldev->release = video_device_release;
  	video_set_drvdata(cam->v4ldev, cam);
  
  	init_completion(&cam->probe);
  
  	err = video_register_device(cam->v4ldev, VFL_TYPE_GRABBER,
  				    video_nr[dev_nr]);
  	if (err) {
  		DBG(1, "V4L2 device registration failed");
  		if (err == -ENFILE && video_nr[dev_nr] == -1)
  			DBG(1, "Free /dev/videoX node not found");
  		video_nr[dev_nr] = -1;
  		dev_nr = (dev_nr < ET61X251_MAX_DEVICES-1) ? dev_nr+1 : 0;
  		complete_all(&cam->probe);
  		goto fail;
  	}
  
  	DBG(2, "V4L2 device registered as /dev/video%d", cam->v4ldev->minor);
  
  	cam->module_param.force_munmap = force_munmap[dev_nr];
  	cam->module_param.frame_timeout = frame_timeout[dev_nr];
  
  	dev_nr = (dev_nr < ET61X251_MAX_DEVICES-1) ? dev_nr+1 : 0;
  
  #ifdef CONFIG_VIDEO_ADV_DEBUG
  	err = et61x251_create_sysfs(cam);
  	if (!err)
  		DBG(2, "Optional device control through 'sysfs' "
  		       "interface ready");
  	else
  		DBG(2, "Failed to create 'sysfs' interface for optional "
  		       "device controlling. Error #%d", err);
  #else
  	DBG(2, "Optional device control through 'sysfs' interface disabled");
  	DBG(3, "Compile the kernel with the 'CONFIG_VIDEO_ADV_DEBUG' "
  	       "configuration option to enable it.");
  #endif
  
  	usb_set_intfdata(intf, cam);
  	kref_init(&cam->kref);
  	usb_get_dev(cam->usbdev);
  
  	complete_all(&cam->probe);
  
  	return 0;
  
  fail:
  	if (cam) {
  		kfree(cam->control_buffer);
  		if (cam->v4ldev)
  			video_device_release(cam->v4ldev);
  		kfree(cam);
  	}
  	return err;
  }
  
  
  static void et61x251_usb_disconnect(struct usb_interface* intf)
  {
  	struct et61x251_device* cam;
  
  	down_write(&et61x251_dev_lock);
  
  	cam = usb_get_intfdata(intf);
  
  	DBG(2, "Disconnecting %s...", cam->v4ldev->name);
  
  	if (cam->users) {
  		DBG(2, "Device /dev/video%d is open! Deregistration and "
  		       "memory deallocation are deferred.",
  		    cam->v4ldev->minor);
  		cam->state |= DEV_MISCONFIGURED;
  		et61x251_stop_transfer(cam);
  		cam->state |= DEV_DISCONNECTED;
  		wake_up_interruptible(&cam->wait_frame);
  		wake_up(&cam->wait_stream);
  	} else
  		cam->state |= DEV_DISCONNECTED;
  
  	wake_up_interruptible_all(&cam->wait_open);
  
  	kref_put(&cam->kref, et61x251_release_resources);
  
  	up_write(&et61x251_dev_lock);
  }
  
  
  static struct usb_driver et61x251_usb_driver = {
  	.name =       "et61x251",
  	.id_table =   et61x251_id_table,
  	.probe =      et61x251_usb_probe,
  	.disconnect = et61x251_usb_disconnect,
  };
  
  /*****************************************************************************/
  
  static int __init et61x251_module_init(void)
  {
  	int err = 0;
  
  	KDBG(2, ET61X251_MODULE_NAME " v" ET61X251_MODULE_VERSION);
  	KDBG(3, ET61X251_MODULE_AUTHOR);
  
  	if ((err = usb_register(&et61x251_usb_driver)))
  		KDBG(1, "usb_register() failed");
  
  	return err;
  }
  
  
  static void __exit et61x251_module_exit(void)
  {
  	usb_deregister(&et61x251_usb_driver);
  }
  
  
  module_init(et61x251_module_init);
  module_exit(et61x251_module_exit);
  