/*
 * Copyright (c) 2013,2016 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 const struct usbtv_norm_params norm_params[] = {
        {
                .norm = V4L2_STD_525_60,
                .cap_width = 720,
                .cap_height = 480,
        },
        {
                .norm = V4L2_STD_625_50,
                .cap_width = 720,
                .cap_height = 576,
        }
};

static int usbtv_configure_for_norm(struct usbtv *usbtv, v4l2_std_id norm)
{
        int i, ret = 0;
        const 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) {
                if (vb2_is_busy(&usbtv->vb2q) &&
                    (usbtv->width != params->cap_width ||
                     usbtv->height != params->cap_height))
                        return -EBUSY;
                usbtv->width = params->cap_width;
                usbtv->height = params->cap_height;
                usbtv->n_chunks = usbtv->width * usbtv->height
                                                / 4 / USBTV_CHUNK;
                usbtv->norm = 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 uint16_t usbtv_norm_to_16f_reg(v4l2_std_id norm)
{
        /* NTSC M/M-JP/M-KR */
        if (norm & V4L2_STD_NTSC)
                return 0x00b8;
        /* PAL BG/DK/H/I */
        if (norm & V4L2_STD_PAL)
                return 0x00ee;
        /* SECAM B/D/G/H/K/K1/L/Lc */
        if (norm & V4L2_STD_SECAM)
                return 0x00ff;
        if (norm & V4L2_STD_NTSC_443)
                return 0x00a8;
        if (norm & (V4L2_STD_PAL_M | V4L2_STD_PAL_60))
                return 0x00bc;
        if (norm & V4L2_STD_PAL_Nc)
                return 0x00fe;
        /* Fallback to automatic detection for other standards */
        return 0x0000;
}

static int usbtv_select_norm(struct usbtv *usbtv, v4l2_std_id norm)
{
        int ret;
        /* These are the series of register values used to configure the
         * decoder for a specific standard.
         * The first 21 register writes are copied from the
         * Settings\DecoderDefaults registry keys present in the Windows driver
         * .INF file, and control various image tuning parameters (color
         * correction, sharpness, ...).
         */
        static const u16 pal[][2] = {
                /* "AVPAL" tuning sequence from .INF file */
                { USBTV_BASE + 0x0003, 0x0004 },
                { USBTV_BASE + 0x001a, 0x0068 },
                { USBTV_BASE + 0x0100, 0x00d3 },
                { USBTV_BASE + 0x010e, 0x0072 },
                { USBTV_BASE + 0x010f, 0x00a2 },
                { USBTV_BASE + 0x0112, 0x00b0 },
                { USBTV_BASE + 0x0115, 0x0015 },
                { USBTV_BASE + 0x0117, 0x0001 },
                { USBTV_BASE + 0x0118, 0x002c },
                { USBTV_BASE + 0x012d, 0x0010 },
                { USBTV_BASE + 0x012f, 0x0020 },
                { USBTV_BASE + 0x0220, 0x002e },
                { USBTV_BASE + 0x0225, 0x0008 },
                { USBTV_BASE + 0x024e, 0x0002 },
                { 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 },
                /* End image tuning */
                { USBTV_BASE + 0x024e, 0x0002 },
                { USBTV_BASE + 0x024f, 0x0002 },
        };

        static const u16 ntsc[][2] = {
                /* "AVNTSC" tuning sequence from .INF file */
                { USBTV_BASE + 0x0003, 0x0004 },
                { USBTV_BASE + 0x001a, 0x0079 },
                { USBTV_BASE + 0x0100, 0x00d3 },
                { USBTV_BASE + 0x010e, 0x0068 },
                { USBTV_BASE + 0x010f, 0x009c },
                { USBTV_BASE + 0x0112, 0x00f0 },
                { USBTV_BASE + 0x0115, 0x0015 },
                { USBTV_BASE + 0x0117, 0x0000 },
                { USBTV_BASE + 0x0118, 0x00fc },
                { USBTV_BASE + 0x012d, 0x0004 },
                { USBTV_BASE + 0x012f, 0x0008 },
                { USBTV_BASE + 0x0220, 0x002e },
                { USBTV_BASE + 0x0225, 0x0008 },
                { USBTV_BASE + 0x024e, 0x0002 },
                { 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 },
                /* End image tuning */
                { USBTV_BASE + 0x024e, 0x0002 },
                { USBTV_BASE + 0x024f, 0x0002 },
        };

        static const u16 secam[][2] = {
                /* "AVSECAM" tuning sequence from .INF file */
                { USBTV_BASE + 0x0003, 0x0004 },
                { USBTV_BASE + 0x001a, 0x0073 },
                { USBTV_BASE + 0x0100, 0x00dc },
                { USBTV_BASE + 0x010e, 0x0072 },
                { USBTV_BASE + 0x010f, 0x00a2 },
                { USBTV_BASE + 0x0112, 0x0090 },
                { USBTV_BASE + 0x0115, 0x0035 },
                { USBTV_BASE + 0x0117, 0x0001 },
                { USBTV_BASE + 0x0118, 0x0030 },
                { USBTV_BASE + 0x012d, 0x0004 },
                { USBTV_BASE + 0x012f, 0x0008 },
                { USBTV_BASE + 0x0220, 0x002d },
                { USBTV_BASE + 0x0225, 0x0028 },
                { USBTV_BASE + 0x024e, 0x0008 },
                { USBTV_BASE + 0x024f, 0x0002 },
                { USBTV_BASE + 0x0254, 0x0069 },
                { USBTV_BASE + 0x025a, 0x0016 },
                { USBTV_BASE + 0x025b, 0x0035 },
                { USBTV_BASE + 0x0263, 0x0021 },
                { USBTV_BASE + 0x0266, 0x0016 },
                { USBTV_BASE + 0x0267, 0x0036 },
                /* End image tuning */
                { USBTV_BASE + 0x024e, 0x0002 },
                { USBTV_BASE + 0x024f, 0x0002 },
        };

        ret = usbtv_configure_for_norm(usbtv, norm);

        if (!ret) {
                /* Masks for norms using a NTSC or PAL color encoding. */
                static const v4l2_std_id ntsc_mask =
                        V4L2_STD_NTSC | V4L2_STD_NTSC_443;
                static const v4l2_std_id pal_mask =
                        V4L2_STD_PAL | V4L2_STD_PAL_60 | V4L2_STD_PAL_M |
                        V4L2_STD_PAL_Nc;

                if (norm & ntsc_mask)
                        ret = usbtv_set_regs(usbtv, ntsc, ARRAY_SIZE(ntsc));
                else if (norm & pal_mask)
                        ret = usbtv_set_regs(usbtv, pal, ARRAY_SIZE(pal));
                else if (norm & V4L2_STD_SECAM)
                        ret = usbtv_set_regs(usbtv, secam, ARRAY_SIZE(secam));
                else
                        ret = -EINVAL;
        }

        if (!ret) {
                /* Configure the decoder for the color standard */
                const u16 cfg[][2] = {
                        { USBTV_BASE + 0x016f, usbtv_norm_to_16f_reg(norm) }
                };
                ret = usbtv_set_regs(usbtv, cfg, ARRAY_SIZE(cfg));
        }

        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 },
        };

        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;

        ret = v4l2_ctrl_handler_setup(&usbtv->ctrl);
        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 = kcalloc(USBTV_ISOC_PACKETS, size,
                                                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);

        strscpy(cap->driver, "usbtv", sizeof(cap->driver));
        strscpy(cap->card, "usbtv", sizeof(cap->card));
        usb_make_path(dev->udev, cap->bus_info, sizeof(cap->bus_info));
        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:
                strscpy(i->name, "Composite", sizeof(i->name));
                break;
        case USBTV_SVIDEO_INPUT:
                strscpy(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;

        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 & USBTV_TV_STD)
                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 const 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 const 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);
        unsigned int q_num_bufs = vb2_get_num_buffers(vq);

        if (q_num_bufs + *nbuffers < 2)
                *nbuffers = 2 - q_num_bufs;
        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 int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
{
        struct usbtv *usbtv = container_of(ctrl->handler, struct usbtv,
                                                                ctrl);
        u8 *data;
        u16 index, size;
        int ret;

        data = kmalloc(3, GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        /*
         * Read in the current brightness/contrast registers. We need them
         * both, because the values are for some reason interleaved.
         */
        if (ctrl->id == V4L2_CID_BRIGHTNESS || ctrl->id == V4L2_CID_CONTRAST) {
                ret = usb_control_msg(usbtv->udev,
                        usb_rcvctrlpipe(usbtv->udev, 0), USBTV_CONTROL_REG,
                        USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                        0, USBTV_BASE + 0x0244, (void *)data, 3,
                        USB_CTRL_GET_TIMEOUT);
                if (ret < 0)
                        goto error;
        }

        switch (ctrl->id) {
        case V4L2_CID_BRIGHTNESS:
                index = USBTV_BASE + 0x0244;
                size = 3;
                data[0] &= 0xf0;
                data[0] |= (ctrl->val >> 8) & 0xf;
                data[2] = ctrl->val & 0xff;
                break;
        case V4L2_CID_CONTRAST:
                index = USBTV_BASE + 0x0244;
                size = 3;
                data[0] &= 0x0f;
                data[0] |= (ctrl->val >> 4) & 0xf0;
                data[1] = ctrl->val & 0xff;
                break;
        case V4L2_CID_SATURATION:
                index = USBTV_BASE + 0x0242;
                data[0] = ctrl->val >> 8;
                data[1] = ctrl->val & 0xff;
                size = 2;
                break;
        case V4L2_CID_HUE:
                index = USBTV_BASE + 0x0240;
                size = 2;
                if (ctrl->val > 0) {
                        data[0] = 0x92 + (ctrl->val >> 8);
                        data[1] = ctrl->val & 0xff;
                } else {
                        data[0] = 0x82 + (-ctrl->val >> 8);
                        data[1] = -ctrl->val & 0xff;
                }
                break;
        case V4L2_CID_SHARPNESS:
                index = USBTV_BASE + 0x0239;
                data[0] = 0;
                data[1] = ctrl->val;
                size = 2;
                break;
        default:
                kfree(data);
                return -EINVAL;
        }

        ret = usb_control_msg(usbtv->udev, usb_sndctrlpipe(usbtv->udev, 0),
                        USBTV_CONTROL_REG,
                        USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                        0, index, (void *)data, size, USB_CTRL_SET_TIMEOUT);

error:
        if (ret < 0)
                dev_warn(usbtv->dev, "Failed to submit a control request.\n");

        kfree(data);
        return ret;
}

static const struct v4l2_ctrl_ops usbtv_ctrl_ops = {
        .s_ctrl = usbtv_s_ctrl,
};

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);
        v4l2_ctrl_handler_free(&usbtv->ctrl);
        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;
        }

        /* controls */
        v4l2_ctrl_handler_init(&usbtv->ctrl, 4);
        v4l2_ctrl_new_std(&usbtv->ctrl, &usbtv_ctrl_ops,
                        V4L2_CID_CONTRAST, 0, 0x3ff, 1, 0x1d0);
        v4l2_ctrl_new_std(&usbtv->ctrl, &usbtv_ctrl_ops,
                        V4L2_CID_BRIGHTNESS, 0, 0x3ff, 1, 0x1c0);
        v4l2_ctrl_new_std(&usbtv->ctrl, &usbtv_ctrl_ops,
                        V4L2_CID_SATURATION, 0, 0x3ff, 1, 0x200);
        v4l2_ctrl_new_std(&usbtv->ctrl, &usbtv_ctrl_ops,
                        V4L2_CID_HUE, -0xdff, 0xdff, 1, 0x000);
        v4l2_ctrl_new_std(&usbtv->ctrl, &usbtv_ctrl_ops,
                        V4L2_CID_SHARPNESS, 0x0, 0xff, 1, 0x60);
        ret = usbtv->ctrl.error;
        if (ret < 0) {
                dev_warn(usbtv->dev, "Could not initialize controls\n");
                goto ctrl_fail;
        }

        /* v4l2 structure */
        usbtv->v4l2_dev.ctrl_handler = &usbtv->ctrl;
        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 */
        strscpy(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;
        usbtv->vdev.device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
                                  V4L2_CAP_STREAMING;
        video_set_drvdata(&usbtv->vdev, usbtv);
        ret = video_register_device(&usbtv->vdev, VFL_TYPE_VIDEO, -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:
ctrl_fail:
        v4l2_ctrl_handler_free(&usbtv->ctrl);

        return ret;
}

void usbtv_video_free(struct usbtv *usbtv)
{
        vb2_video_unregister_device(&usbtv->vdev);
        v4l2_device_disconnect(&usbtv->v4l2_dev);

        v4l2_device_put(&usbtv->v4l2_dev);
}