drivers/media/usb/usbtv/usbtv-video.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2013 Lubomir Rintel
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions, and the following disclaimer,
  *    without modification.
  * 2. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * Alternatively, this software may be distributed under the terms of the
  * GNU General Public License ("GPL").
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /*
  * Fushicai USBTV007 Audio-Video Grabber Driver
  *
  * Product web site:
  * http://www.fushicai.com/products_detail/&productId=d05449ee-b690-42f9-a661-aa7353894bed.html
  *
  * Following LWN articles were very useful in construction of this driver:
  * Video4Linux2 API series: http://lwn.net/Articles/203924/
  * videobuf2 API explanation: http://lwn.net/Articles/447435/
  * Thanks go to Jonathan Corbet for providing this quality documentation.
  * He is awesome.
  *
  * No physical hardware was harmed running Windows during the
  * reverse-engineering activity
  */

 #include <media/v4l2-ioctl.h>
 #include <media/videobuf2-v4l2.h>

 #include "usbtv.h"

 static struct usbtv_norm_params norm_params[] = {
 	{
 		.norm = V4L2_STD_525_60,
 		.cap_width = 720,
 		.cap_height = 480,
 	},
 	{
 		.norm = V4L2_STD_PAL,
 		.cap_width = 720,
 		.cap_height = 576,
 	}
 };

 static int usbtv_configure_for_norm(struct usbtv *usbtv, v4l2_std_id norm)
 {
 	int i, ret = 0;
 	struct usbtv_norm_params *params = NULL;

 	for (i = 0; i < ARRAY_SIZE(norm_params); i++) {
 		if (norm_params[i].norm & norm) {
 			params = &norm_params[i];
 			break;
 		}
 	}

 	if (params) {
 		usbtv->width = params->cap_width;
 		usbtv->height = params->cap_height;
 		usbtv->n_chunks = usbtv->width * usbtv->height
 						/ 4 / USBTV_CHUNK;
 		usbtv->norm = params->norm;
 	} else
 		ret = -EINVAL;

 	return ret;
 }

 static int usbtv_select_input(struct usbtv *usbtv, int input)
 {
 	int ret;

 	static const u16 composite[][2] = {
 		{ USBTV_BASE + 0x0105, 0x0060 },
 		{ USBTV_BASE + 0x011f, 0x00f2 },
 		{ USBTV_BASE + 0x0127, 0x0060 },
 		{ USBTV_BASE + 0x00ae, 0x0010 },
 		{ USBTV_BASE + 0x0239, 0x0060 },
 	};

 	static const u16 svideo[][2] = {
 		{ USBTV_BASE + 0x0105, 0x0010 },
 		{ USBTV_BASE + 0x011f, 0x00ff },
 		{ USBTV_BASE + 0x0127, 0x0060 },
 		{ USBTV_BASE + 0x00ae, 0x0030 },
 		{ USBTV_BASE + 0x0239, 0x0060 },
 	};

 	switch (input) {
 	case USBTV_COMPOSITE_INPUT:
 		ret = usbtv_set_regs(usbtv, composite, ARRAY_SIZE(composite));
 		break;
 	case USBTV_SVIDEO_INPUT:
 		ret = usbtv_set_regs(usbtv, svideo, ARRAY_SIZE(svideo));
 		break;
 	default:
 		ret = -EINVAL;
 	}

 	if (!ret)
 		usbtv->input = input;

 	return ret;
 }

 static int usbtv_select_norm(struct usbtv *usbtv, v4l2_std_id norm)
 {
 	int ret;
 	static const u16 pal[][2] = {
 		{ USBTV_BASE + 0x001a, 0x0068 },
 		{ USBTV_BASE + 0x010e, 0x0072 },
 		{ USBTV_BASE + 0x010f, 0x00a2 },
 		{ USBTV_BASE + 0x0112, 0x00b0 },
 		{ USBTV_BASE + 0x0117, 0x0001 },
 		{ USBTV_BASE + 0x0118, 0x002c },
 		{ USBTV_BASE + 0x012d, 0x0010 },
 		{ USBTV_BASE + 0x012f, 0x0020 },
 		{ USBTV_BASE + 0x024f, 0x0002 },
 		{ USBTV_BASE + 0x0254, 0x0059 },
 		{ USBTV_BASE + 0x025a, 0x0016 },
 		{ USBTV_BASE + 0x025b, 0x0035 },
 		{ USBTV_BASE + 0x0263, 0x0017 },
 		{ USBTV_BASE + 0x0266, 0x0016 },
 		{ USBTV_BASE + 0x0267, 0x0036 }
 	};

 	static const u16 ntsc[][2] = {
 		{ USBTV_BASE + 0x001a, 0x0079 },
 		{ USBTV_BASE + 0x010e, 0x0068 },
 		{ USBTV_BASE + 0x010f, 0x009c },
 		{ USBTV_BASE + 0x0112, 0x00f0 },
 		{ USBTV_BASE + 0x0117, 0x0000 },
 		{ USBTV_BASE + 0x0118, 0x00fc },
 		{ USBTV_BASE + 0x012d, 0x0004 },
 		{ USBTV_BASE + 0x012f, 0x0008 },
 		{ USBTV_BASE + 0x024f, 0x0001 },
 		{ USBTV_BASE + 0x0254, 0x005f },
 		{ USBTV_BASE + 0x025a, 0x0012 },
 		{ USBTV_BASE + 0x025b, 0x0001 },
 		{ USBTV_BASE + 0x0263, 0x001c },
 		{ USBTV_BASE + 0x0266, 0x0011 },
 		{ USBTV_BASE + 0x0267, 0x0005 }
 	};

 	ret = usbtv_configure_for_norm(usbtv, norm);

 	if (!ret) {
 		if (norm & V4L2_STD_525_60)
 			ret = usbtv_set_regs(usbtv, ntsc, ARRAY_SIZE(ntsc));
 		else if (norm & V4L2_STD_PAL)
 			ret = usbtv_set_regs(usbtv, pal, ARRAY_SIZE(pal));
 	}

 	return ret;
 }

 static int usbtv_setup_capture(struct usbtv *usbtv)
 {
 	int ret;
 	static const u16 setup[][2] = {
 		/* These seem to enable the device. */
 		{ USBTV_BASE + 0x0008, 0x0001 },
 		{ USBTV_BASE + 0x01d0, 0x00ff },
 		{ USBTV_BASE + 0x01d9, 0x0002 },

 		/* These seem to influence color parameters, such as
 		 * brightness, etc. */
 		{ USBTV_BASE + 0x0239, 0x0040 },
 		{ USBTV_BASE + 0x0240, 0x0000 },
 		{ USBTV_BASE + 0x0241, 0x0000 },
 		{ USBTV_BASE + 0x0242, 0x0002 },
 		{ USBTV_BASE + 0x0243, 0x0080 },
 		{ USBTV_BASE + 0x0244, 0x0012 },
 		{ USBTV_BASE + 0x0245, 0x0090 },
 		{ USBTV_BASE + 0x0246, 0x0000 },

 		{ USBTV_BASE + 0x0278, 0x002d },
 		{ USBTV_BASE + 0x0279, 0x000a },
 		{ USBTV_BASE + 0x027a, 0x0032 },
 		{ 0xf890, 0x000c },
 		{ 0xf894, 0x0086 },

 		{ USBTV_BASE + 0x00ac, 0x00c0 },
 		{ USBTV_BASE + 0x00ad, 0x0000 },
 		{ USBTV_BASE + 0x00a2, 0x0012 },
 		{ USBTV_BASE + 0x00a3, 0x00e0 },
 		{ USBTV_BASE + 0x00a4, 0x0028 },
 		{ USBTV_BASE + 0x00a5, 0x0082 },
 		{ USBTV_BASE + 0x00a7, 0x0080 },
 		{ USBTV_BASE + 0x0000, 0x0014 },
 		{ USBTV_BASE + 0x0006, 0x0003 },
 		{ USBTV_BASE + 0x0090, 0x0099 },
 		{ USBTV_BASE + 0x0091, 0x0090 },
 		{ USBTV_BASE + 0x0094, 0x0068 },
 		{ USBTV_BASE + 0x0095, 0x0070 },
 		{ USBTV_BASE + 0x009c, 0x0030 },
 		{ USBTV_BASE + 0x009d, 0x00c0 },
 		{ USBTV_BASE + 0x009e, 0x00e0 },
 		{ USBTV_BASE + 0x0019, 0x0006 },
 		{ USBTV_BASE + 0x008c, 0x00ba },
 		{ USBTV_BASE + 0x0101, 0x00ff },
 		{ USBTV_BASE + 0x010c, 0x00b3 },
 		{ USBTV_BASE + 0x01b2, 0x0080 },
 		{ USBTV_BASE + 0x01b4, 0x00a0 },
 		{ USBTV_BASE + 0x014c, 0x00ff },
 		{ USBTV_BASE + 0x014d, 0x00ca },
 		{ USBTV_BASE + 0x0113, 0x0053 },
 		{ USBTV_BASE + 0x0119, 0x008a },
 		{ USBTV_BASE + 0x013c, 0x0003 },
 		{ USBTV_BASE + 0x0150, 0x009c },
 		{ USBTV_BASE + 0x0151, 0x0071 },
 		{ USBTV_BASE + 0x0152, 0x00c6 },
 		{ USBTV_BASE + 0x0153, 0x0084 },
 		{ USBTV_BASE + 0x0154, 0x00bc },
 		{ USBTV_BASE + 0x0155, 0x00a0 },
 		{ USBTV_BASE + 0x0156, 0x00a0 },
 		{ USBTV_BASE + 0x0157, 0x009c },
 		{ USBTV_BASE + 0x0158, 0x001f },
 		{ USBTV_BASE + 0x0159, 0x0006 },
 		{ USBTV_BASE + 0x015d, 0x0000 },

 		{ USBTV_BASE + 0x0003, 0x0004 },
 		{ USBTV_BASE + 0x0100, 0x00d3 },
 		{ USBTV_BASE + 0x0115, 0x0015 },
 		{ USBTV_BASE + 0x0220, 0x002e },
 		{ USBTV_BASE + 0x0225, 0x0008 },
 		{ USBTV_BASE + 0x024e, 0x0002 },
 		{ USBTV_BASE + 0x024e, 0x0002 },
 		{ USBTV_BASE + 0x024f, 0x0002 },
 	};

 	ret = usbtv_set_regs(usbtv, setup, ARRAY_SIZE(setup));
 	if (ret)
 		return ret;

 	ret = usbtv_select_norm(usbtv, usbtv->norm);
 	if (ret)
 		return ret;

 	ret = usbtv_select_input(usbtv, usbtv->input);
 	if (ret)
 		return ret;

 	return 0;
 }

 /* Copy data from chunk into a frame buffer, deinterlacing the data
  * into every second line. Unfortunately, they don't align nicely into
  * 720 pixel lines, as the chunk is 240 words long, which is 480 pixels.
  * Therefore, we break down the chunk into two halves before copying,
  * so that we can interleave a line if needed.
  *
  * Each "chunk" is 240 words; a word in this context equals 4 bytes.
  * Image format is YUYV/YUV 4:2:2, consisting of Y Cr Y Cb, defining two
  * pixels, the Cr and Cb shared between the two pixels, but each having
  * separate Y values. Thus, the 240 words equal 480 pixels. It therefore,
  * takes 1.5 chunks to make a 720 pixel-wide line for the frame.
  * The image is interlaced, so there is a "scan" of odd lines, followed
  * by "scan" of even numbered lines.
  *
  * Following code is writing the chunks in correct sequence, skipping
  * the rows based on "odd" value.
  * line 1: chunk[0][  0..479] chunk[0][480..959] chunk[1][  0..479]
  * line 3: chunk[1][480..959] chunk[2][  0..479] chunk[2][480..959]
  * ...etc.
  */
 static void usbtv_chunk_to_vbuf(u32 *frame, __be32 *src, int chunk_no, int odd)
 {
 	int half;

 	for (half = 0; half < 2; half++) {
 		int part_no = chunk_no * 2 + half;
 		int line = part_no / 3;
 		int part_index = (line * 2 + !odd) * 3 + (part_no % 3);

 		u32 *dst = &frame[part_index * USBTV_CHUNK/2];

 		memcpy(dst, src, USBTV_CHUNK/2 * sizeof(*src));
 		src += USBTV_CHUNK/2;
 	}
 }

 /* Called for each 256-byte image chunk.
  * First word identifies the chunk, followed by 240 words of image
  * data and padding. */
 static void usbtv_image_chunk(struct usbtv *usbtv, __be32 *chunk)
 {
 	int frame_id, odd, chunk_no;
 	u32 *frame;
 	struct usbtv_buf *buf;
 	unsigned long flags;

 	/* Ignore corrupted lines. */
 	if (!USBTV_MAGIC_OK(chunk))
 		return;
 	frame_id = USBTV_FRAME_ID(chunk);
 	odd = USBTV_ODD(chunk);
 	chunk_no = USBTV_CHUNK_NO(chunk);
 	if (chunk_no >= usbtv->n_chunks)
 		return;

 	/* Beginning of a frame. */
 	if (chunk_no == 0) {
 		usbtv->frame_id = frame_id;
 		usbtv->chunks_done = 0;
 	}

 	if (usbtv->frame_id != frame_id)
 		return;

 	spin_lock_irqsave(&usbtv->buflock, flags);
 	if (list_empty(&usbtv->bufs)) {
 		/* No free buffers. Userspace likely too slow. */
 		spin_unlock_irqrestore(&usbtv->buflock, flags);
 		return;
 	}

 	/* First available buffer. */
 	buf = list_first_entry(&usbtv->bufs, struct usbtv_buf, list);
 	frame = vb2_plane_vaddr(&buf->vb.vb2_buf, 0);

 	/* Copy the chunk data. */
 	usbtv_chunk_to_vbuf(frame, &chunk[1], chunk_no, odd);
 	usbtv->chunks_done++;

 	/* Last chunk in a field */
 	if (chunk_no == usbtv->n_chunks-1) {
 		/* Last chunk in a frame, signalling an end */
 		if (odd && !usbtv->last_odd) {
 			int size = vb2_plane_size(&buf->vb.vb2_buf, 0);
 			enum vb2_buffer_state state = usbtv->chunks_done ==
 				usbtv->n_chunks ?
 				VB2_BUF_STATE_DONE :
 				VB2_BUF_STATE_ERROR;

 			buf->vb.field = V4L2_FIELD_INTERLACED;
 			buf->vb.sequence = usbtv->sequence++;
 			buf->vb.vb2_buf.timestamp = ktime_get_ns();
 			vb2_set_plane_payload(&buf->vb.vb2_buf, 0, size);
 			vb2_buffer_done(&buf->vb.vb2_buf, state);
 			list_del(&buf->list);
 		}
 		usbtv->last_odd = odd;
 	}

 	spin_unlock_irqrestore(&usbtv->buflock, flags);
 }

 /* Got image data. Each packet contains a number of 256-word chunks we
  * compose the image from. */
 static void usbtv_iso_cb(struct urb *ip)
 {
 	int ret;
 	int i;
 	struct usbtv *usbtv = (struct usbtv *)ip->context;

 	switch (ip->status) {
 	/* All fine. */
 	case 0:
 		break;
 	/* Device disconnected or capture stopped? */
 	case -ENODEV:
 	case -ENOENT:
 	case -ECONNRESET:
 	case -ESHUTDOWN:
 		return;
 	/* Unknown error. Retry. */
 	default:
 		dev_warn(usbtv->dev, "Bad response for ISO request.\n");
 		goto resubmit;
 	}

 	for (i = 0; i < ip->number_of_packets; i++) {
 		int size = ip->iso_frame_desc[i].actual_length;
 		unsigned char *data = ip->transfer_buffer +
 				ip->iso_frame_desc[i].offset;
 		int offset;

 		for (offset = 0; USBTV_CHUNK_SIZE * offset < size; offset++)
 			usbtv_image_chunk(usbtv,
 				(__be32 *)&data[USBTV_CHUNK_SIZE * offset]);
 	}

 resubmit:
 	ret = usb_submit_urb(ip, GFP_ATOMIC);
 	if (ret < 0)
 		dev_warn(usbtv->dev, "Could not resubmit ISO URB\n");
 }

 static struct urb *usbtv_setup_iso_transfer(struct usbtv *usbtv)
 {
 	struct urb *ip;
 	int size = usbtv->iso_size;
 	int i;

 	ip = usb_alloc_urb(USBTV_ISOC_PACKETS, GFP_KERNEL);
 	if (ip == NULL)
 		return NULL;

 	ip->dev = usbtv->udev;
 	ip->context = usbtv;
 	ip->pipe = usb_rcvisocpipe(usbtv->udev, USBTV_VIDEO_ENDP);
 	ip->interval = 1;
 	ip->transfer_flags = URB_ISO_ASAP;
 	ip->transfer_buffer = kzalloc(size * USBTV_ISOC_PACKETS,
 						GFP_KERNEL);
 	if (!ip->transfer_buffer) {
 		usb_free_urb(ip);
 		return NULL;
 	}
 	ip->complete = usbtv_iso_cb;
 	ip->number_of_packets = USBTV_ISOC_PACKETS;
 	ip->transfer_buffer_length = size * USBTV_ISOC_PACKETS;
 	for (i = 0; i < USBTV_ISOC_PACKETS; i++) {
 		ip->iso_frame_desc[i].offset = size * i;
 		ip->iso_frame_desc[i].length = size;
 	}

 	return ip;
 }

 static void usbtv_stop(struct usbtv *usbtv)
 {
 	int i;
 	unsigned long flags;

 	/* Cancel running transfers. */
 	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
 		struct urb *ip = usbtv->isoc_urbs[i];

 		if (ip == NULL)
 			continue;
 		usb_kill_urb(ip);
 		kfree(ip->transfer_buffer);
 		usb_free_urb(ip);
 		usbtv->isoc_urbs[i] = NULL;
 	}

 	/* Return buffers to userspace. */
 	spin_lock_irqsave(&usbtv->buflock, flags);
 	while (!list_empty(&usbtv->bufs)) {
 		struct usbtv_buf *buf = list_first_entry(&usbtv->bufs,
 						struct usbtv_buf, list);
 		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
 		list_del(&buf->list);
 	}
 	spin_unlock_irqrestore(&usbtv->buflock, flags);
 }

 static int usbtv_start(struct usbtv *usbtv)
 {
 	int i;
 	int ret;

 	usbtv_audio_suspend(usbtv);

 	ret = usb_set_interface(usbtv->udev, 0, 0);
 	if (ret < 0)
 		return ret;

 	ret = usbtv_setup_capture(usbtv);
 	if (ret < 0)
 		return ret;

 	ret = usb_set_interface(usbtv->udev, 0, 1);
 	if (ret < 0)
 		return ret;

 	usbtv_audio_resume(usbtv);

 	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
 		struct urb *ip;

 		ip = usbtv_setup_iso_transfer(usbtv);
 		if (ip == NULL) {
 			ret = -ENOMEM;
 			goto start_fail;
 		}
 		usbtv->isoc_urbs[i] = ip;

 		ret = usb_submit_urb(ip, GFP_KERNEL);
 		if (ret < 0)
 			goto start_fail;
 	}

 	return 0;

 start_fail:
 	usbtv_stop(usbtv);
 	return ret;
 }

 static int usbtv_querycap(struct file *file, void *priv,
 				struct v4l2_capability *cap)
 {
 	struct usbtv *dev = video_drvdata(file);

 	strlcpy(cap->driver, "usbtv", sizeof(cap->driver));
 	strlcpy(cap->card, "usbtv", sizeof(cap->card));
 	usb_make_path(dev->udev, cap->bus_info, sizeof(cap->bus_info));
 	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE;
 	cap->device_caps |= V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
 	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
 	return 0;
 }

 static int usbtv_enum_input(struct file *file, void *priv,
 					struct v4l2_input *i)
 {
 	struct usbtv *dev = video_drvdata(file);

 	switch (i->index) {
 	case USBTV_COMPOSITE_INPUT:
 		strlcpy(i->name, "Composite", sizeof(i->name));
 		break;
 	case USBTV_SVIDEO_INPUT:
 		strlcpy(i->name, "S-Video", sizeof(i->name));
 		break;
 	default:
 		return -EINVAL;
 	}

 	i->type = V4L2_INPUT_TYPE_CAMERA;
 	i->std = dev->vdev.tvnorms;
 	return 0;
 }

 static int usbtv_enum_fmt_vid_cap(struct file *file, void  *priv,
 					struct v4l2_fmtdesc *f)
 {
 	if (f->index > 0)
 		return -EINVAL;

 	strlcpy(f->description, "16 bpp YUY2, 4:2:2, packed",
 					sizeof(f->description));
 	f->pixelformat = V4L2_PIX_FMT_YUYV;
 	return 0;
 }

 static int usbtv_fmt_vid_cap(struct file *file, void *priv,
 					struct v4l2_format *f)
 {
 	struct usbtv *usbtv = video_drvdata(file);

 	f->fmt.pix.width = usbtv->width;
 	f->fmt.pix.height = usbtv->height;
 	f->fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
 	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
 	f->fmt.pix.bytesperline = usbtv->width * 2;
 	f->fmt.pix.sizeimage = (f->fmt.pix.bytesperline * f->fmt.pix.height);
 	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;

 	return 0;
 }

 static int usbtv_g_std(struct file *file, void *priv, v4l2_std_id *norm)
 {
 	struct usbtv *usbtv = video_drvdata(file);
 	*norm = usbtv->norm;
 	return 0;
 }

 static int usbtv_s_std(struct file *file, void *priv, v4l2_std_id norm)
 {
 	int ret = -EINVAL;
 	struct usbtv *usbtv = video_drvdata(file);

 	if ((norm & V4L2_STD_525_60) || (norm & V4L2_STD_PAL))
 		ret = usbtv_select_norm(usbtv, norm);

 	return ret;
 }

 static int usbtv_g_input(struct file *file, void *priv, unsigned int *i)
 {
 	struct usbtv *usbtv = video_drvdata(file);
 	*i = usbtv->input;
 	return 0;
 }

 static int usbtv_s_input(struct file *file, void *priv, unsigned int i)
 {
 	struct usbtv *usbtv = video_drvdata(file);

 	return usbtv_select_input(usbtv, i);
 }

 static struct v4l2_ioctl_ops usbtv_ioctl_ops = {
 	.vidioc_querycap = usbtv_querycap,
 	.vidioc_enum_input = usbtv_enum_input,
 	.vidioc_enum_fmt_vid_cap = usbtv_enum_fmt_vid_cap,
 	.vidioc_g_fmt_vid_cap = usbtv_fmt_vid_cap,
 	.vidioc_try_fmt_vid_cap = usbtv_fmt_vid_cap,
 	.vidioc_s_fmt_vid_cap = usbtv_fmt_vid_cap,
 	.vidioc_g_std = usbtv_g_std,
 	.vidioc_s_std = usbtv_s_std,
 	.vidioc_g_input = usbtv_g_input,
 	.vidioc_s_input = usbtv_s_input,

 	.vidioc_reqbufs = vb2_ioctl_reqbufs,
 	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
 	.vidioc_querybuf = vb2_ioctl_querybuf,
 	.vidioc_create_bufs = vb2_ioctl_create_bufs,
 	.vidioc_qbuf = vb2_ioctl_qbuf,
 	.vidioc_dqbuf = vb2_ioctl_dqbuf,
 	.vidioc_streamon = vb2_ioctl_streamon,
 	.vidioc_streamoff = vb2_ioctl_streamoff,
 };

 static struct v4l2_file_operations usbtv_fops = {
 	.owner = THIS_MODULE,
 	.unlocked_ioctl = video_ioctl2,
 	.mmap = vb2_fop_mmap,
 	.open = v4l2_fh_open,
 	.release = vb2_fop_release,
 	.read = vb2_fop_read,
 	.poll = vb2_fop_poll,
 };

 static int usbtv_queue_setup(struct vb2_queue *vq,
 	unsigned int *nbuffers,
 	unsigned int *nplanes, unsigned int sizes[], struct device *alloc_devs[])
 {
 	struct usbtv *usbtv = vb2_get_drv_priv(vq);
 	unsigned size = USBTV_CHUNK * usbtv->n_chunks * 2 * sizeof(u32);

 	if (vq->num_buffers + *nbuffers < 2)
 		*nbuffers = 2 - vq->num_buffers;
 	if (*nplanes)
 		return sizes[0] < size ? -EINVAL : 0;
 	*nplanes = 1;
 	sizes[0] = size;

 	return 0;
 }

 static void usbtv_buf_queue(struct vb2_buffer *vb)
 {
 	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
 	struct usbtv *usbtv = vb2_get_drv_priv(vb->vb2_queue);
 	struct usbtv_buf *buf = container_of(vbuf, struct usbtv_buf, vb);
 	unsigned long flags;

 	if (usbtv->udev == NULL) {
 		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
 		return;
 	}

 	spin_lock_irqsave(&usbtv->buflock, flags);
 	list_add_tail(&buf->list, &usbtv->bufs);
 	spin_unlock_irqrestore(&usbtv->buflock, flags);
 }

 static int usbtv_start_streaming(struct vb2_queue *vq, unsigned int count)
 {
 	struct usbtv *usbtv = vb2_get_drv_priv(vq);

 	if (usbtv->udev == NULL)
 		return -ENODEV;

 	usbtv->last_odd = 1;
 	usbtv->sequence = 0;
 	return usbtv_start(usbtv);
 }

 static void usbtv_stop_streaming(struct vb2_queue *vq)
 {
 	struct usbtv *usbtv = vb2_get_drv_priv(vq);

 	if (usbtv->udev)
 		usbtv_stop(usbtv);
 }

 static const struct vb2_ops usbtv_vb2_ops = {
 	.queue_setup = usbtv_queue_setup,
 	.buf_queue = usbtv_buf_queue,
 	.start_streaming = usbtv_start_streaming,
 	.stop_streaming = usbtv_stop_streaming,
 };

 static void usbtv_release(struct v4l2_device *v4l2_dev)
 {
 	struct usbtv *usbtv = container_of(v4l2_dev, struct usbtv, v4l2_dev);

 	v4l2_device_unregister(&usbtv->v4l2_dev);
 	vb2_queue_release(&usbtv->vb2q);
 	kfree(usbtv);
 }

 int usbtv_video_init(struct usbtv *usbtv)
 {
 	int ret;

 	(void)usbtv_configure_for_norm(usbtv, V4L2_STD_525_60);

 	spin_lock_init(&usbtv->buflock);
 	mutex_init(&usbtv->v4l2_lock);
 	mutex_init(&usbtv->vb2q_lock);
 	INIT_LIST_HEAD(&usbtv->bufs);

 	/* videobuf2 structure */
 	usbtv->vb2q.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 	usbtv->vb2q.io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
 	usbtv->vb2q.drv_priv = usbtv;
 	usbtv->vb2q.buf_struct_size = sizeof(struct usbtv_buf);
 	usbtv->vb2q.ops = &usbtv_vb2_ops;
 	usbtv->vb2q.mem_ops = &vb2_vmalloc_memops;
 	usbtv->vb2q.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 	usbtv->vb2q.lock = &usbtv->vb2q_lock;
 	ret = vb2_queue_init(&usbtv->vb2q);
 	if (ret < 0) {
 		dev_warn(usbtv->dev, "Could not initialize videobuf2 queue\n");
 		return ret;
 	}

 	/* v4l2 structure */
 	usbtv->v4l2_dev.release = usbtv_release;
 	ret = v4l2_device_register(usbtv->dev, &usbtv->v4l2_dev);
 	if (ret < 0) {
 		dev_warn(usbtv->dev, "Could not register v4l2 device\n");
 		goto v4l2_fail;
 	}

 	/* Video structure */
 	strlcpy(usbtv->vdev.name, "usbtv", sizeof(usbtv->vdev.name));
 	usbtv->vdev.v4l2_dev = &usbtv->v4l2_dev;
 	usbtv->vdev.release = video_device_release_empty;
 	usbtv->vdev.fops = &usbtv_fops;
 	usbtv->vdev.ioctl_ops = &usbtv_ioctl_ops;
 	usbtv->vdev.tvnorms = USBTV_TV_STD;
 	usbtv->vdev.queue = &usbtv->vb2q;
 	usbtv->vdev.lock = &usbtv->v4l2_lock;
 	video_set_drvdata(&usbtv->vdev, usbtv);
 	ret = video_register_device(&usbtv->vdev, VFL_TYPE_GRABBER, -1);
 	if (ret < 0) {
 		dev_warn(usbtv->dev, "Could not register video device\n");
 		goto vdev_fail;
 	}

 	return 0;

 vdev_fail:
 	v4l2_device_unregister(&usbtv->v4l2_dev);
 v4l2_fail:
 	vb2_queue_release(&usbtv->vb2q);

 	return ret;
 }

 void usbtv_video_free(struct usbtv *usbtv)
 {
 	mutex_lock(&usbtv->vb2q_lock);
 	mutex_lock(&usbtv->v4l2_lock);

 	usbtv_stop(usbtv);
 	video_unregister_device(&usbtv->vdev);
 	v4l2_device_disconnect(&usbtv->v4l2_dev);

 	mutex_unlock(&usbtv->v4l2_lock);
 	mutex_unlock(&usbtv->vb2q_lock);

 	v4l2_device_put(&usbtv->v4l2_dev);
 }
	/*
	* Copyright (c) 2013 Lubomir Rintel
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions, and the following disclaimer,
	* without modification.
	* 2. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* Alternatively, this software may be distributed under the terms of the
	* GNU General Public License ("GPL").
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	/*
	* Fushicai USBTV007 Audio-Video Grabber Driver
	*
	* Product web site:
	* http://www.fushicai.com/products_detail/&productId=d05449ee-b690-42f9-a661-aa7353894bed.html
	*
	* Following LWN articles were very useful in construction of this driver:
	* Video4Linux2 API series: http://lwn.net/Articles/203924/
	* videobuf2 API explanation: http://lwn.net/Articles/447435/
	* Thanks go to Jonathan Corbet for providing this quality documentation.
	* He is awesome.
	*
	* No physical hardware was harmed running Windows during the
	* reverse-engineering activity
	*/

	#include <media/v4l2-ioctl.h>
	#include <media/videobuf2-v4l2.h>

	#include "usbtv.h"

	static struct usbtv_norm_params norm_params[] = {
	{
	.norm = V4L2_STD_525_60,
	.cap_width = 720,
	.cap_height = 480,
	},
	{
	.norm = V4L2_STD_PAL,
	.cap_width = 720,
	.cap_height = 576,
	}
	};

	static int usbtv_configure_for_norm(struct usbtv *usbtv, v4l2_std_id norm)
	{
	int i, ret = 0;
	struct usbtv_norm_params *params = NULL;

	for (i = 0; i < ARRAY_SIZE(norm_params); i++) {
	if (norm_params[i].norm & norm) {
	params = &norm_params[i];
	break;
	}
	}

	if (params) {
	usbtv->width = params->cap_width;
	usbtv->height = params->cap_height;
	usbtv->n_chunks = usbtv->width * usbtv->height
	/ 4 / USBTV_CHUNK;
	usbtv->norm = params->norm;
	} else
	ret = -EINVAL;

	return ret;
	}

	static int usbtv_select_input(struct usbtv *usbtv, int input)
	{
	int ret;

	static const u16 composite[][2] = {
	{ USBTV_BASE + 0x0105, 0x0060 },
	{ USBTV_BASE + 0x011f, 0x00f2 },
	{ USBTV_BASE + 0x0127, 0x0060 },
	{ USBTV_BASE + 0x00ae, 0x0010 },
	{ USBTV_BASE + 0x0239, 0x0060 },
	};

	static const u16 svideo[][2] = {
	{ USBTV_BASE + 0x0105, 0x0010 },
	{ USBTV_BASE + 0x011f, 0x00ff },
	{ USBTV_BASE + 0x0127, 0x0060 },
	{ USBTV_BASE + 0x00ae, 0x0030 },
	{ USBTV_BASE + 0x0239, 0x0060 },
	};

	switch (input) {
	case USBTV_COMPOSITE_INPUT:
	ret = usbtv_set_regs(usbtv, composite, ARRAY_SIZE(composite));
	break;
	case USBTV_SVIDEO_INPUT:
	ret = usbtv_set_regs(usbtv, svideo, ARRAY_SIZE(svideo));
	break;
	default:
	ret = -EINVAL;
	}

	if (!ret)
	usbtv->input = input;

	return ret;
	}

	static int usbtv_select_norm(struct usbtv *usbtv, v4l2_std_id norm)
	{
	int ret;
	static const u16 pal[][2] = {
	{ USBTV_BASE + 0x001a, 0x0068 },
	{ USBTV_BASE + 0x010e, 0x0072 },
	{ USBTV_BASE + 0x010f, 0x00a2 },
	{ USBTV_BASE + 0x0112, 0x00b0 },
	{ USBTV_BASE + 0x0117, 0x0001 },
	{ USBTV_BASE + 0x0118, 0x002c },
	{ USBTV_BASE + 0x012d, 0x0010 },
	{ USBTV_BASE + 0x012f, 0x0020 },
	{ USBTV_BASE + 0x024f, 0x0002 },
	{ USBTV_BASE + 0x0254, 0x0059 },
	{ USBTV_BASE + 0x025a, 0x0016 },
	{ USBTV_BASE + 0x025b, 0x0035 },
	{ USBTV_BASE + 0x0263, 0x0017 },
	{ USBTV_BASE + 0x0266, 0x0016 },
	{ USBTV_BASE + 0x0267, 0x0036 }
	};

	static const u16 ntsc[][2] = {
	{ USBTV_BASE + 0x001a, 0x0079 },
	{ USBTV_BASE + 0x010e, 0x0068 },
	{ USBTV_BASE + 0x010f, 0x009c },
	{ USBTV_BASE + 0x0112, 0x00f0 },
	{ USBTV_BASE + 0x0117, 0x0000 },
	{ USBTV_BASE + 0x0118, 0x00fc },
	{ USBTV_BASE + 0x012d, 0x0004 },
	{ USBTV_BASE + 0x012f, 0x0008 },
	{ USBTV_BASE + 0x024f, 0x0001 },
	{ USBTV_BASE + 0x0254, 0x005f },
	{ USBTV_BASE + 0x025a, 0x0012 },
	{ USBTV_BASE + 0x025b, 0x0001 },
	{ USBTV_BASE + 0x0263, 0x001c },
	{ USBTV_BASE + 0x0266, 0x0011 },
	{ USBTV_BASE + 0x0267, 0x0005 }
	};

	ret = usbtv_configure_for_norm(usbtv, norm);

	if (!ret) {
	if (norm & V4L2_STD_525_60)
	ret = usbtv_set_regs(usbtv, ntsc, ARRAY_SIZE(ntsc));
	else if (norm & V4L2_STD_PAL)
	ret = usbtv_set_regs(usbtv, pal, ARRAY_SIZE(pal));
	}

	return ret;
	}

	static int usbtv_setup_capture(struct usbtv *usbtv)
	{
	int ret;
	static const u16 setup[][2] = {
	/* These seem to enable the device. */
	{ USBTV_BASE + 0x0008, 0x0001 },
	{ USBTV_BASE + 0x01d0, 0x00ff },
	{ USBTV_BASE + 0x01d9, 0x0002 },

	/* These seem to influence color parameters, such as
	* brightness, etc. */
	{ USBTV_BASE + 0x0239, 0x0040 },
	{ USBTV_BASE + 0x0240, 0x0000 },
	{ USBTV_BASE + 0x0241, 0x0000 },
	{ USBTV_BASE + 0x0242, 0x0002 },
	{ USBTV_BASE + 0x0243, 0x0080 },
	{ USBTV_BASE + 0x0244, 0x0012 },
	{ USBTV_BASE + 0x0245, 0x0090 },
	{ USBTV_BASE + 0x0246, 0x0000 },

	{ USBTV_BASE + 0x0278, 0x002d },
	{ USBTV_BASE + 0x0279, 0x000a },
	{ USBTV_BASE + 0x027a, 0x0032 },
	{ 0xf890, 0x000c },
	{ 0xf894, 0x0086 },

	{ USBTV_BASE + 0x00ac, 0x00c0 },
	{ USBTV_BASE + 0x00ad, 0x0000 },
	{ USBTV_BASE + 0x00a2, 0x0012 },
	{ USBTV_BASE + 0x00a3, 0x00e0 },
	{ USBTV_BASE + 0x00a4, 0x0028 },
	{ USBTV_BASE + 0x00a5, 0x0082 },
	{ USBTV_BASE + 0x00a7, 0x0080 },
	{ USBTV_BASE + 0x0000, 0x0014 },
	{ USBTV_BASE + 0x0006, 0x0003 },
	{ USBTV_BASE + 0x0090, 0x0099 },
	{ USBTV_BASE + 0x0091, 0x0090 },
	{ USBTV_BASE + 0x0094, 0x0068 },
	{ USBTV_BASE + 0x0095, 0x0070 },
	{ USBTV_BASE + 0x009c, 0x0030 },
	{ USBTV_BASE + 0x009d, 0x00c0 },
	{ USBTV_BASE + 0x009e, 0x00e0 },
	{ USBTV_BASE + 0x0019, 0x0006 },
	{ USBTV_BASE + 0x008c, 0x00ba },
	{ USBTV_BASE + 0x0101, 0x00ff },
	{ USBTV_BASE + 0x010c, 0x00b3 },
	{ USBTV_BASE + 0x01b2, 0x0080 },
	{ USBTV_BASE + 0x01b4, 0x00a0 },
	{ USBTV_BASE + 0x014c, 0x00ff },
	{ USBTV_BASE + 0x014d, 0x00ca },
	{ USBTV_BASE + 0x0113, 0x0053 },
	{ USBTV_BASE + 0x0119, 0x008a },
	{ USBTV_BASE + 0x013c, 0x0003 },
	{ USBTV_BASE + 0x0150, 0x009c },
	{ USBTV_BASE + 0x0151, 0x0071 },
	{ USBTV_BASE + 0x0152, 0x00c6 },
	{ USBTV_BASE + 0x0153, 0x0084 },
	{ USBTV_BASE + 0x0154, 0x00bc },
	{ USBTV_BASE + 0x0155, 0x00a0 },
	{ USBTV_BASE + 0x0156, 0x00a0 },
	{ USBTV_BASE + 0x0157, 0x009c },
	{ USBTV_BASE + 0x0158, 0x001f },
	{ USBTV_BASE + 0x0159, 0x0006 },
	{ USBTV_BASE + 0x015d, 0x0000 },

	{ USBTV_BASE + 0x0003, 0x0004 },
	{ USBTV_BASE + 0x0100, 0x00d3 },
	{ USBTV_BASE + 0x0115, 0x0015 },
	{ USBTV_BASE + 0x0220, 0x002e },
	{ USBTV_BASE + 0x0225, 0x0008 },
	{ USBTV_BASE + 0x024e, 0x0002 },
	{ USBTV_BASE + 0x024e, 0x0002 },
	{ USBTV_BASE + 0x024f, 0x0002 },
	};

	ret = usbtv_set_regs(usbtv, setup, ARRAY_SIZE(setup));
	if (ret)
	return ret;

	ret = usbtv_select_norm(usbtv, usbtv->norm);
	if (ret)
	return ret;

	ret = usbtv_select_input(usbtv, usbtv->input);
	if (ret)
	return ret;

	return 0;
	}

	/* Copy data from chunk into a frame buffer, deinterlacing the data
	* into every second line. Unfortunately, they don't align nicely into
	* 720 pixel lines, as the chunk is 240 words long, which is 480 pixels.
	* Therefore, we break down the chunk into two halves before copying,
	* so that we can interleave a line if needed.
	*
	* Each "chunk" is 240 words; a word in this context equals 4 bytes.
	* Image format is YUYV/YUV 4:2:2, consisting of Y Cr Y Cb, defining two
	* pixels, the Cr and Cb shared between the two pixels, but each having
	* separate Y values. Thus, the 240 words equal 480 pixels. It therefore,
	* takes 1.5 chunks to make a 720 pixel-wide line for the frame.
	* The image is interlaced, so there is a "scan" of odd lines, followed
	* by "scan" of even numbered lines.
	*
	* Following code is writing the chunks in correct sequence, skipping
	* the rows based on "odd" value.
	* line 1: chunk[0][ 0..479] chunk[0][480..959] chunk[1][ 0..479]
	* line 3: chunk[1][480..959] chunk[2][ 0..479] chunk[2][480..959]
	* ...etc.
	*/
	static void usbtv_chunk_to_vbuf(u32 frame, __be32 src, int chunk_no, int odd)
	{
	int half;

	for (half = 0; half < 2; half++) {
	int part_no = chunk_no * 2 + half;
	int line = part_no / 3;
	int part_index = (line * 2 + !odd) * 3 + (part_no % 3);

	u32 dst = &frame[part_index USBTV_CHUNK/2];

	memcpy(dst, src, USBTV_CHUNK/2 * sizeof(*src));
	src += USBTV_CHUNK/2;
	}
	}

	/* Called for each 256-byte image chunk.
	* First word identifies the chunk, followed by 240 words of image
	* data and padding. */
	static void usbtv_image_chunk(struct usbtv usbtv, __be32 chunk)
	{
	int frame_id, odd, chunk_no;
	u32 *frame;
	struct usbtv_buf *buf;
	unsigned long flags;

	/* Ignore corrupted lines. */
	if (!USBTV_MAGIC_OK(chunk))
	return;
	frame_id = USBTV_FRAME_ID(chunk);
	odd = USBTV_ODD(chunk);
	chunk_no = USBTV_CHUNK_NO(chunk);
	if (chunk_no >= usbtv->n_chunks)
	return;

	/* Beginning of a frame. */
	if (chunk_no == 0) {
	usbtv->frame_id = frame_id;
	usbtv->chunks_done = 0;
	}

	if (usbtv->frame_id != frame_id)
	return;

	spin_lock_irqsave(&usbtv->buflock, flags);
	if (list_empty(&usbtv->bufs)) {
	/* No free buffers. Userspace likely too slow. */
	spin_unlock_irqrestore(&usbtv->buflock, flags);
	return;
	}

	/* First available buffer. */
	buf = list_first_entry(&usbtv->bufs, struct usbtv_buf, list);
	frame = vb2_plane_vaddr(&buf->vb.vb2_buf, 0);

	/* Copy the chunk data. */
	usbtv_chunk_to_vbuf(frame, &chunk[1], chunk_no, odd);
	usbtv->chunks_done++;

	/* Last chunk in a field */
	if (chunk_no == usbtv->n_chunks-1) {
	/* Last chunk in a frame, signalling an end */
	if (odd && !usbtv->last_odd) {
	int size = vb2_plane_size(&buf->vb.vb2_buf, 0);
	enum vb2_buffer_state state = usbtv->chunks_done ==
	usbtv->n_chunks ?
	VB2_BUF_STATE_DONE :
	VB2_BUF_STATE_ERROR;

	buf->vb.field = V4L2_FIELD_INTERLACED;
	buf->vb.sequence = usbtv->sequence++;
	buf->vb.vb2_buf.timestamp = ktime_get_ns();
	vb2_set_plane_payload(&buf->vb.vb2_buf, 0, size);
	vb2_buffer_done(&buf->vb.vb2_buf, state);
	list_del(&buf->list);
	}
	usbtv->last_odd = odd;
	}

	spin_unlock_irqrestore(&usbtv->buflock, flags);
	}

	/* Got image data. Each packet contains a number of 256-word chunks we
	* compose the image from. */
	static void usbtv_iso_cb(struct urb *ip)
	{
	int ret;
	int i;
	struct usbtv usbtv = (struct usbtv )ip->context;

	switch (ip->status) {
	/* All fine. */
	case 0:
	break;
	/* Device disconnected or capture stopped? */
	case -ENODEV:
	case -ENOENT:
	case -ECONNRESET:
	case -ESHUTDOWN:
	return;
	/* Unknown error. Retry. */
	default:
	dev_warn(usbtv->dev, "Bad response for ISO request.\n");
	goto resubmit;
	}

	for (i = 0; i < ip->number_of_packets; i++) {
	int size = ip->iso_frame_desc[i].actual_length;
	unsigned char *data = ip->transfer_buffer +
	ip->iso_frame_desc[i].offset;
	int offset;

	for (offset = 0; USBTV_CHUNK_SIZE * offset < size; offset++)
	usbtv_image_chunk(usbtv,
	(__be32 )&data[USBTV_CHUNK_SIZE offset]);
	}

	resubmit:
	ret = usb_submit_urb(ip, GFP_ATOMIC);
	if (ret < 0)
	dev_warn(usbtv->dev, "Could not resubmit ISO URB\n");
	}

	static struct urb usbtv_setup_iso_transfer(struct usbtv usbtv)
	{
	struct urb *ip;
	int size = usbtv->iso_size;
	int i;

	ip = usb_alloc_urb(USBTV_ISOC_PACKETS, GFP_KERNEL);
	if (ip == NULL)
	return NULL;

	ip->dev = usbtv->udev;
	ip->context = usbtv;
	ip->pipe = usb_rcvisocpipe(usbtv->udev, USBTV_VIDEO_ENDP);
	ip->interval = 1;
	ip->transfer_flags = URB_ISO_ASAP;
	ip->transfer_buffer = kzalloc(size * USBTV_ISOC_PACKETS,
	GFP_KERNEL);
	if (!ip->transfer_buffer) {
	usb_free_urb(ip);
	return NULL;
	}
	ip->complete = usbtv_iso_cb;
	ip->number_of_packets = USBTV_ISOC_PACKETS;
	ip->transfer_buffer_length = size * USBTV_ISOC_PACKETS;
	for (i = 0; i < USBTV_ISOC_PACKETS; i++) {
	ip->iso_frame_desc[i].offset = size * i;
	ip->iso_frame_desc[i].length = size;
	}

	return ip;
	}

	static void usbtv_stop(struct usbtv *usbtv)
	{
	int i;
	unsigned long flags;

	/* Cancel running transfers. */
	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
	struct urb *ip = usbtv->isoc_urbs[i];

	if (ip == NULL)
	continue;
	usb_kill_urb(ip);
	kfree(ip->transfer_buffer);
	usb_free_urb(ip);
	usbtv->isoc_urbs[i] = NULL;
	}

	/* Return buffers to userspace. */
	spin_lock_irqsave(&usbtv->buflock, flags);
	while (!list_empty(&usbtv->bufs)) {
	struct usbtv_buf *buf = list_first_entry(&usbtv->bufs,
	struct usbtv_buf, list);
	vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
	list_del(&buf->list);
	}
	spin_unlock_irqrestore(&usbtv->buflock, flags);
	}

	static int usbtv_start(struct usbtv *usbtv)
	{
	int i;
	int ret;

	usbtv_audio_suspend(usbtv);

	ret = usb_set_interface(usbtv->udev, 0, 0);
	if (ret < 0)
	return ret;

	ret = usbtv_setup_capture(usbtv);
	if (ret < 0)
	return ret;

	ret = usb_set_interface(usbtv->udev, 0, 1);
	if (ret < 0)
	return ret;

	usbtv_audio_resume(usbtv);

	for (i = 0; i < USBTV_ISOC_TRANSFERS; i++) {
	struct urb *ip;

	ip = usbtv_setup_iso_transfer(usbtv);
	if (ip == NULL) {
	ret = -ENOMEM;
	goto start_fail;
	}
	usbtv->isoc_urbs[i] = ip;

	ret = usb_submit_urb(ip, GFP_KERNEL);
	if (ret < 0)
	goto start_fail;
	}

	return 0;

	start_fail:
	usbtv_stop(usbtv);
	return ret;
	}

	static int usbtv_querycap(struct file file, void priv,
	struct v4l2_capability *cap)
	{
	struct usbtv *dev = video_drvdata(file);

	strlcpy(cap->driver, "usbtv", sizeof(cap->driver));
	strlcpy(cap->card, "usbtv", sizeof(cap->card));
	usb_make_path(dev->udev, cap->bus_info, sizeof(cap->bus_info));
	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE;
	cap->device_caps \|= V4L2_CAP_READWRITE \| V4L2_CAP_STREAMING;
	cap->capabilities = cap->device_caps \| V4L2_CAP_DEVICE_CAPS;
	return 0;
	}

	static int usbtv_enum_input(struct file file, void priv,
	struct v4l2_input *i)
	{
	struct usbtv *dev = video_drvdata(file);

	switch (i->index) {
	case USBTV_COMPOSITE_INPUT:
	strlcpy(i->name, "Composite", sizeof(i->name));
	break;
	case USBTV_SVIDEO_INPUT:
	strlcpy(i->name, "S-Video", sizeof(i->name));
	break;
	default:
	return -EINVAL;
	}

	i->type = V4L2_INPUT_TYPE_CAMERA;
	i->std = dev->vdev.tvnorms;
	return 0;
	}

	static int usbtv_enum_fmt_vid_cap(struct file file, void priv,
	struct v4l2_fmtdesc *f)
	{
	if (f->index > 0)
	return -EINVAL;

	strlcpy(f->description, "16 bpp YUY2, 4:2:2, packed",
	sizeof(f->description));
	f->pixelformat = V4L2_PIX_FMT_YUYV;
	return 0;
	}

	static int usbtv_fmt_vid_cap(struct file file, void priv,
	struct v4l2_format *f)
	{
	struct usbtv *usbtv = video_drvdata(file);

	f->fmt.pix.width = usbtv->width;
	f->fmt.pix.height = usbtv->height;
	f->fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
	f->fmt.pix.bytesperline = usbtv->width * 2;
	f->fmt.pix.sizeimage = (f->fmt.pix.bytesperline * f->fmt.pix.height);
	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;

	return 0;
	}

	static int usbtv_g_std(struct file file, void priv, v4l2_std_id *norm)
	{
	struct usbtv *usbtv = video_drvdata(file);
	*norm = usbtv->norm;
	return 0;
	}

	static int usbtv_s_std(struct file file, void priv, v4l2_std_id norm)
	{
	int ret = -EINVAL;
	struct usbtv *usbtv = video_drvdata(file);

	if ((norm & V4L2_STD_525_60) \|\| (norm & V4L2_STD_PAL))
	ret = usbtv_select_norm(usbtv, norm);

	return ret;
	}

	static int usbtv_g_input(struct file file, void priv, unsigned int *i)
	{
	struct usbtv *usbtv = video_drvdata(file);
	*i = usbtv->input;
	return 0;
	}

	static int usbtv_s_input(struct file file, void priv, unsigned int i)
	{
	struct usbtv *usbtv = video_drvdata(file);

	return usbtv_select_input(usbtv, i);
	}

	static struct v4l2_ioctl_ops usbtv_ioctl_ops = {
	.vidioc_querycap = usbtv_querycap,
	.vidioc_enum_input = usbtv_enum_input,
	.vidioc_enum_fmt_vid_cap = usbtv_enum_fmt_vid_cap,
	.vidioc_g_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_try_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_s_fmt_vid_cap = usbtv_fmt_vid_cap,
	.vidioc_g_std = usbtv_g_std,
	.vidioc_s_std = usbtv_s_std,
	.vidioc_g_input = usbtv_g_input,
	.vidioc_s_input = usbtv_s_input,

	.vidioc_reqbufs = vb2_ioctl_reqbufs,
	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
	.vidioc_querybuf = vb2_ioctl_querybuf,
	.vidioc_create_bufs = vb2_ioctl_create_bufs,
	.vidioc_qbuf = vb2_ioctl_qbuf,
	.vidioc_dqbuf = vb2_ioctl_dqbuf,
	.vidioc_streamon = vb2_ioctl_streamon,
	.vidioc_streamoff = vb2_ioctl_streamoff,
	};

	static struct v4l2_file_operations usbtv_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = video_ioctl2,
	.mmap = vb2_fop_mmap,
	.open = v4l2_fh_open,
	.release = vb2_fop_release,
	.read = vb2_fop_read,
	.poll = vb2_fop_poll,
	};

	static int usbtv_queue_setup(struct vb2_queue *vq,
	unsigned int *nbuffers,
	unsigned int nplanes, unsigned int sizes[], struct device alloc_devs[])
	{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);
	unsigned size = USBTV_CHUNK * usbtv->n_chunks * 2 * sizeof(u32);

	if (vq->num_buffers + *nbuffers < 2)
	*nbuffers = 2 - vq->num_buffers;
	if (*nplanes)
	return sizes[0] < size ? -EINVAL : 0;
	*nplanes = 1;
	sizes[0] = size;

	return 0;
	}

	static void usbtv_buf_queue(struct vb2_buffer *vb)
	{
	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
	struct usbtv *usbtv = vb2_get_drv_priv(vb->vb2_queue);
	struct usbtv_buf *buf = container_of(vbuf, struct usbtv_buf, vb);
	unsigned long flags;

	if (usbtv->udev == NULL) {
	vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
	return;
	}

	spin_lock_irqsave(&usbtv->buflock, flags);
	list_add_tail(&buf->list, &usbtv->bufs);
	spin_unlock_irqrestore(&usbtv->buflock, flags);
	}

	static int usbtv_start_streaming(struct vb2_queue *vq, unsigned int count)
	{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);

	if (usbtv->udev == NULL)
	return -ENODEV;

	usbtv->last_odd = 1;
	usbtv->sequence = 0;
	return usbtv_start(usbtv);
	}

	static void usbtv_stop_streaming(struct vb2_queue *vq)
	{
	struct usbtv *usbtv = vb2_get_drv_priv(vq);

	if (usbtv->udev)
	usbtv_stop(usbtv);
	}

	static const struct vb2_ops usbtv_vb2_ops = {
	.queue_setup = usbtv_queue_setup,
	.buf_queue = usbtv_buf_queue,
	.start_streaming = usbtv_start_streaming,
	.stop_streaming = usbtv_stop_streaming,
	};

	static void usbtv_release(struct v4l2_device *v4l2_dev)
	{
	struct usbtv *usbtv = container_of(v4l2_dev, struct usbtv, v4l2_dev);

	v4l2_device_unregister(&usbtv->v4l2_dev);
	vb2_queue_release(&usbtv->vb2q);
	kfree(usbtv);
	}

	int usbtv_video_init(struct usbtv *usbtv)
	{
	int ret;

	(void)usbtv_configure_for_norm(usbtv, V4L2_STD_525_60);

	spin_lock_init(&usbtv->buflock);
	mutex_init(&usbtv->v4l2_lock);
	mutex_init(&usbtv->vb2q_lock);
	INIT_LIST_HEAD(&usbtv->bufs);

	/* videobuf2 structure */
	usbtv->vb2q.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	usbtv->vb2q.io_modes = VB2_MMAP \| VB2_USERPTR \| VB2_READ;
	usbtv->vb2q.drv_priv = usbtv;
	usbtv->vb2q.buf_struct_size = sizeof(struct usbtv_buf);
	usbtv->vb2q.ops = &usbtv_vb2_ops;
	usbtv->vb2q.mem_ops = &vb2_vmalloc_memops;
	usbtv->vb2q.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
	usbtv->vb2q.lock = &usbtv->vb2q_lock;
	ret = vb2_queue_init(&usbtv->vb2q);
	if (ret < 0) {
	dev_warn(usbtv->dev, "Could not initialize videobuf2 queue\n");
	return ret;
	}

	/* v4l2 structure */
	usbtv->v4l2_dev.release = usbtv_release;
	ret = v4l2_device_register(usbtv->dev, &usbtv->v4l2_dev);
	if (ret < 0) {
	dev_warn(usbtv->dev, "Could not register v4l2 device\n");
	goto v4l2_fail;
	}

	/* Video structure */
	strlcpy(usbtv->vdev.name, "usbtv", sizeof(usbtv->vdev.name));
	usbtv->vdev.v4l2_dev = &usbtv->v4l2_dev;
	usbtv->vdev.release = video_device_release_empty;
	usbtv->vdev.fops = &usbtv_fops;
	usbtv->vdev.ioctl_ops = &usbtv_ioctl_ops;
	usbtv->vdev.tvnorms = USBTV_TV_STD;
	usbtv->vdev.queue = &usbtv->vb2q;
	usbtv->vdev.lock = &usbtv->v4l2_lock;
	video_set_drvdata(&usbtv->vdev, usbtv);
	ret = video_register_device(&usbtv->vdev, VFL_TYPE_GRABBER, -1);
	if (ret < 0) {
	dev_warn(usbtv->dev, "Could not register video device\n");
	goto vdev_fail;
	}

	return 0;

	vdev_fail:
	v4l2_device_unregister(&usbtv->v4l2_dev);
	v4l2_fail:
	vb2_queue_release(&usbtv->vb2q);

	return ret;
	}

	void usbtv_video_free(struct usbtv *usbtv)
	{
	mutex_lock(&usbtv->vb2q_lock);
	mutex_lock(&usbtv->v4l2_lock);

	usbtv_stop(usbtv);
	video_unregister_device(&usbtv->vdev);
	v4l2_device_disconnect(&usbtv->v4l2_dev);

	mutex_unlock(&usbtv->v4l2_lock);
	mutex_unlock(&usbtv->vb2q_lock);

	v4l2_device_put(&usbtv->v4l2_dev);
	}