This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / drivers / usb / media / et61x251_core.c
diff --git a/drivers/usb/media/et61x251_core.c b/drivers/usb/media/et61x251_core.c
new file mode 100644 (file)
index 0000000..2c0171a
--- /dev/null
@@ -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;
+       }
+
+       if ((val = et61x251_read_reg(cam, cam->sysfs.reg)) < 0) {
+               up(&et61x251_sysfs_lock);
+               return -EIO;
+       }
+
+       count = sprintf(buf, "%d\n", val);
+
+       DBG(3, "Read bytes: %zd", count);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static ssize_t
+et61x251_store_val(struct class_device* cd, const char* buf, size_t len)
+{
+       struct et61x251_device* cam;
+       u8 value;
+       ssize_t count;
+       int err;
+
+       if (down_interruptible(&et61x251_sysfs_lock))
+               return -ERESTARTSYS;
+
+       cam = video_get_drvdata(to_video_device(cd));
+       if (!cam) {
+               up(&et61x251_sysfs_lock);
+               return -ENODEV;
+       }
+
+       value = et61x251_strtou8(buf, len, &count);
+       if (!count) {
+               up(&et61x251_sysfs_lock);
+               return -EINVAL;
+       }
+
+       err = et61x251_write_reg(cam, value, cam->sysfs.reg);
+       if (err) {
+               up(&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);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static ssize_t et61x251_show_i2c_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.i2c_reg);
+
+       DBG(3, "Read bytes: %zd", count);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static ssize_t
+et61x251_store_i2c_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 (!count) {
+               up(&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);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static ssize_t et61x251_show_i2c_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;
+       }
+
+       if (!(cam->sensor->sysfs_ops & ET61X251_I2C_READ)) {
+               up(&et61x251_sysfs_lock);
+               return -ENOSYS;
+       }
+
+       if ((val = et61x251_i2c_read(cam, cam->sysfs.i2c_reg)) < 0) {
+               up(&et61x251_sysfs_lock);
+               return -EIO;
+       }
+
+       count = sprintf(buf, "%d\n", val);
+
+       DBG(3, "Read bytes: %zd", count);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static ssize_t
+et61x251_store_i2c_val(struct class_device* cd, const char* buf, size_t len)
+{
+       struct et61x251_device* cam;
+       u8 value;
+       ssize_t count;
+       int err;
+
+       if (down_interruptible(&et61x251_sysfs_lock))
+               return -ERESTARTSYS;
+
+       cam = video_get_drvdata(to_video_device(cd));
+       if (!cam) {
+               up(&et61x251_sysfs_lock);
+               return -ENODEV;
+       }
+
+       if (!(cam->sensor->sysfs_ops & ET61X251_I2C_READ)) {
+               up(&et61x251_sysfs_lock);
+               return -ENOSYS;
+       }
+
+       value = et61x251_strtou8(buf, len, &count);
+       if (!count) {
+               up(&et61x251_sysfs_lock);
+               return -EINVAL;
+       }
+
+       err = et61x251_i2c_write(cam, cam->sysfs.i2c_reg, value);
+       if (err) {
+               up(&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);
+
+       up(&et61x251_sysfs_lock);
+
+       return count;
+}
+
+
+static CLASS_DEVICE_ATTR(reg, S_IRUGO | S_IWUSR,
+                         et61x251_show_reg, et61x251_store_reg);
+static CLASS_DEVICE_ATTR(val, S_IRUGO | S_IWUSR,
+                         et61x251_show_val, et61x251_store_val);
+static CLASS_DEVICE_ATTR(i2c_reg, S_IRUGO | S_IWUSR,
+                         et61x251_show_i2c_reg, et61x251_store_i2c_reg);
+static CLASS_DEVICE_ATTR(i2c_val, S_IRUGO | S_IWUSR,
+                         et61x251_show_i2c_val, et61x251_store_i2c_val);
+
+
+static void et61x251_create_sysfs(struct et61x251_device* cam)
+{
+       struct video_device *v4ldev = cam->v4ldev;
+
+       video_device_create_file(v4ldev, &class_device_attr_reg);
+       video_device_create_file(v4ldev, &class_device_attr_val);
+       if (cam->sensor && cam->sensor->sysfs_ops) {
+               video_device_create_file(v4ldev, &class_device_attr_i2c_reg);
+               video_device_create_file(v4ldev, &class_device_attr_i2c_val);
+       }
+}
+#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)) {
+               init_waitqueue_head(&cam->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)) {
+               init_MUTEX(&cam->fileop_sem);
+               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 et61x251_device* cam)
+{
+       down(&et61x251_sysfs_lock);
+
+       DBG(2, "V4L2 device /dev/video%d deregistered", cam->v4ldev->minor);
+       video_set_drvdata(cam->v4ldev, NULL);
+       video_unregister_device(cam->v4ldev);
+
+       up(&et61x251_sysfs_lock);
+
+       kfree(cam->control_buffer);
+}
+
+/*****************************************************************************/
+
+static int et61x251_open(struct inode* inode, struct file* filp)
+{
+       struct et61x251_device* cam;
+       int err = 0;
+
+       /*
+          This is the only safe way to prevent race conditions with
+          disconnect
+       */
+       if (!down_read_trylock(&et61x251_disconnect))
+               return -ERESTARTSYS;
+
+       cam = video_get_drvdata(video_devdata(filp));
+
+       if (down_interruptible(&cam->dev_sem)) {
+               up_read(&et61x251_disconnect);
+               return -ERESTARTSYS;
+       }
+
+       if (cam->users) {
+               DBG(2, "Device /dev/video%d is busy...", cam->v4ldev->minor);
+               if ((filp->f_flags & O_NONBLOCK) ||
+                   (filp->f_flags & O_NDELAY)) {
+                       err = -EWOULDBLOCK;
+                       goto out;
+               }
+               up(&cam->dev_sem);
+               err = wait_event_interruptible_exclusive(cam->open,
+                                                 cam->state & DEV_DISCONNECTED
+                                                        || !cam->users);
+               if (err) {
+                       up_read(&et61x251_disconnect);
+                       return err;
+               }
+               if (cam->state & DEV_DISCONNECTED) {
+                       up_read(&et61x251_disconnect);
+                       return -ENODEV;
+               }
+               down(&cam->dev_sem);
+       }
+
+
+       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:
+       up(&cam->dev_sem);
+       up_read(&et61x251_disconnect);
+       return err;
+}
+
+
+static int et61x251_release(struct inode* inode, struct file* filp)
+{
+       struct et61x251_device* cam = video_get_drvdata(video_devdata(filp));
+
+       down(&cam->dev_sem); /* prevent disconnect() to be called */
+
+       et61x251_stop_transfer(cam);
+
+       et61x251_release_buffers(cam);
+
+       if (cam->state & DEV_DISCONNECTED) {
+               et61x251_release_resources(cam);
+               up(&cam->dev_sem);
+               kfree(cam);
+               return 0;
+       }
+
+       cam->users--;
+       wake_up_interruptible_nr(&cam->open, 1);
+
+       DBG(3, "Video device /dev/video%d closed", cam->v4ldev->minor);
+
+       up(&cam->dev_sem);
+
+       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;
+       int err = 0;
+
+       if (down_interruptible(&cam->fileop_sem))
+               return -ERESTARTSYS;
+
+       if (cam->state & DEV_DISCONNECTED) {
+               DBG(1, "Device not present");
+               up(&cam->fileop_sem);
+               return -ENODEV;
+       }
+
+       if (cam->state & DEV_MISCONFIGURED) {
+               DBG(1, "The camera is misconfigured. Close and open it "
+                      "again.");
+               up(&cam->fileop_sem);
+               return -EIO;
+       }
+
+       if (cam->io == IO_MMAP) {
+               DBG(3, "Close and open the device again to choose the read "
+                      "method");
+               up(&cam->fileop_sem);
+               return -EINVAL;
+       }
+
+       if (cam->io == IO_NONE) {
+               if (!et61x251_request_buffers(cam, cam->nreadbuffers,
+                                             IO_READ)) {
+                       DBG(1, "read() failed, not enough memory");
+                       up(&cam->fileop_sem);
+                       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) {
+               up(&cam->fileop_sem);
+               return 0;
+       }
+
+       if (list_empty(&cam->outqueue)) {
+               if (filp->f_flags & O_NONBLOCK) {
+                       up(&cam->fileop_sem);
+                       return -EAGAIN;
+               }
+               err = wait_event_interruptible
+                     ( cam->wait_frame,
+                       (!list_empty(&cam->outqueue)) ||
+                       (cam->state & DEV_DISCONNECTED) ||
+                       (cam->state & DEV_MISCONFIGURED) );
+               if (err) {
+                       up(&cam->fileop_sem);
+                       return err;
+               }
+               if (cam->state & DEV_DISCONNECTED) {
+                       up(&cam->fileop_sem);
+                       return -ENODEV;
+               }
+               if (cam->state & DEV_MISCONFIGURED) {
+                       up(&cam->fileop_sem);
+                       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);
+
+       up(&cam->fileop_sem);
+
+       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 (down_interruptible(&cam->fileop_sem))
+               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;
+
+       up(&cam->fileop_sem);
+
+       return mask;
+
+error:
+       up(&cam->fileop_sem);
+       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 (down_interruptible(&cam->fileop_sem))
+               return -ERESTARTSYS;
+
+       if (cam->state & DEV_DISCONNECTED) {
+               DBG(1, "Device not present");
+               up(&cam->fileop_sem);
+               return -ENODEV;
+       }
+
+       if (cam->state & DEV_MISCONFIGURED) {
+               DBG(1, "The camera is misconfigured. Close and open it "
+                      "again.");
+               up(&cam->fileop_sem);
+               return -EIO;
+       }
+
+       if (cam->io != IO_MMAP || !(vma->vm_flags & VM_WRITE) ||
+           size != PAGE_ALIGN(cam->frame[0].buf.length)) {
+               up(&cam->fileop_sem);
+               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) {
+               up(&cam->fileop_sem);
+               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))) {
+                       up(&cam->fileop_sem);
+                       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);
+
+       up(&cam->fileop_sem);
+
+       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");
+
+       if (copy_to_user(arg, &i, sizeof(i)))
+               return -EFAULT;
+
+       return 0;
+}
+
+
+static int
+et61x251_vidioc_gs_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 (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 -EINVAL;
+                       }
+
+       /* 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 < 4)
+               rect->width = 4;
+       if (rect->height < 4)
+               rect->height = 4;
+       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 &= ~3L;
+       rect->height &= ~3L;
+
+       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_fmt(struct et61x251_device* cam, void __user * arg)
+{
+       struct v4l2_fmtdesc fmtd;
+
+       if (copy_from_user(&fmtd, arg, sizeof(fmtd)))
+               return -EFAULT;
+
+       if (fmtd.index == 0) {
+               strcpy(fmtd.description, "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->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 < 4)
+               rect.width = 4;
+       if (rect.height < 4)
+               rect.height = 4;
+       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 &= ~3L;
+       rect.height &= ~3L;
+
+       { /* 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 = 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 -EINVAL;
+                       }
+
+       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 -EINVAL;
+       }
+
+       for (i = 0; i < cam->nbuffers; i++)
+               if (cam->frame[i].vma_use_count) {
+                       DBG(3, "VIDIOC_REQBUFS failed. "
+                              "Previous buffers are still mapped.");
+                       return -EINVAL;
+               }
+
+       if (cam->stream == STREAM_ON)
+               if ((err = 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;
+       int err = 0;
+
+       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;
+               err = wait_event_interruptible
+                     ( cam->wait_frame,
+                       (!list_empty(&cam->outqueue)) ||
+                       (cam->state & DEV_DISCONNECTED) ||
+                       (cam->state & DEV_MISCONFIGURED) );
+               if (err)
+                       return err;
+               if (cam->state & DEV_DISCONNECTED)
+                       return -ENODEV;
+               if (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;
+
+       if (list_empty(&cam->inqueue))
+               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:
+       case VIDIOC_S_INPUT:
+               return et61x251_vidioc_gs_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_OLD:
+       case VIDIOC_S_CTRL:
+               return et61x251_vidioc_s_ctrl(cam, arg);
+
+       case VIDIOC_CROPCAP_OLD:
+       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_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_OLD:
+       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:
+               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 (down_interruptible(&cam->fileop_sem))
+               return -ERESTARTSYS;
+
+       if (cam->state & DEV_DISCONNECTED) {
+               DBG(1, "Device not present");
+               up(&cam->fileop_sem);
+               return -ENODEV;
+       }
+
+       if (cam->state & DEV_MISCONFIGURED) {
+               DBG(1, "The camera is misconfigured. Close and open it "
+                      "again.");
+               up(&cam->fileop_sem);
+               return -EIO;
+       }
+
+       V4LDBG(3, "et61x251", cmd);
+
+       err = et61x251_ioctl_v4l2(inode, filp, cmd, (void __user *)arg);
+
+       up(&cam->fileop_sem);
+
+       return err;
+}
+
+
+static struct file_operations et61x251_fops = {
+       .owner = THIS_MODULE,
+       .open =    et61x251_open,
+       .release = et61x251_release,
+       .ioctl =   et61x251_ioctl,
+       .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;
+       }
+
+       init_MUTEX(&cam->dev_sem);
+
+       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 && cam->sensor)
+               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->hardware = 0;
+       cam->v4ldev->fops = &et61x251_fops;
+       cam->v4ldev->minor = video_nr[dev_nr];
+       cam->v4ldev->release = video_device_release;
+       video_set_drvdata(cam->v4ldev, cam);
+
+       down(&cam->dev_sem);
+
+       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;
+               up(&cam->dev_sem);
+               goto fail;
+       }
+
+       DBG(2, "V4L2 device registered as /dev/video%d", cam->v4ldev->minor);
+
+       cam->module_param.force_munmap = force_munmap[dev_nr];
+
+       dev_nr = (dev_nr < ET61X251_MAX_DEVICES-1) ? dev_nr+1 : 0;
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+       et61x251_create_sysfs(cam);
+       DBG(2, "Optional device control through 'sysfs' interface ready");
+#endif
+
+       usb_set_intfdata(intf, cam);
+
+       up(&cam->dev_sem);
+
+       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 = usb_get_intfdata(intf);
+
+       if (!cam)
+               return;
+
+       down_write(&et61x251_disconnect);
+
+       down(&cam->dev_sem);
+
+       DBG(2, "Disconnecting %s...", cam->v4ldev->name);
+
+       wake_up_interruptible_all(&cam->open);
+
+       if (cam->users) {
+               DBG(2, "Device /dev/video%d is open! Deregistration and "
+                      "memory deallocation are deferred on close.",
+                   cam->v4ldev->minor);
+               cam->state |= DEV_MISCONFIGURED;
+               et61x251_stop_transfer(cam);
+               cam->state |= DEV_DISCONNECTED;
+               wake_up_interruptible(&cam->wait_frame);
+               wake_up_interruptible(&cam->wait_stream);
+       } else {
+               cam->state |= DEV_DISCONNECTED;
+               et61x251_release_resources(cam);
+       }
+
+       up(&cam->dev_sem);
+
+       if (!cam->users)
+               kfree(cam);
+
+       up_write(&et61x251_disconnect);
+}
+
+
+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);