samples: v4l: from Documentation to samples directory
authorArnd Bergmann <arnd@arndb.de>
Mon, 25 Apr 2016 16:03:09 +0000 (18:03 +0200)
committerJonathan Corbet <corbet@lwn.net>
Thu, 28 Apr 2016 13:47:59 +0000 (07:47 -0600)
A small bug with the new autoksyms support showed that there are
two kernel modules in the Documentation directory that qualify
as samples, while all other samples are in the samples/ directory.

This patch was originally meant as a workaround for that bug, but
it has now been solved in a different way. However, I still think
it makes sense as a cleanup to consolidate all sample code in
one place.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Documentation/Makefile
Documentation/video4linux/Makefile [deleted file]
Documentation/video4linux/v4l2-framework.txt
Documentation/video4linux/v4l2-pci-skeleton.c [deleted file]
samples/Makefile
samples/v4l/Makefile [new file with mode: 0644]
samples/v4l/v4l2-pci-skeleton.c [new file with mode: 0644]

index 13b5ae1..de955e1 100644 (file)
@@ -1,4 +1,3 @@
 subdir-y := accounting auxdisplay blackfin \
        filesystems filesystems ia64 laptops mic misc-devices \
-       networking pcmcia prctl ptp timers vDSO video4linux \
-       watchdog
+       networking pcmcia prctl ptp timers vDSO watchdog
diff --git a/Documentation/video4linux/Makefile b/Documentation/video4linux/Makefile
deleted file mode 100644 (file)
index 65a351d..0000000
+++ /dev/null
@@ -1 +0,0 @@
-obj-$(CONFIG_VIDEO_PCI_SKELETON) := v4l2-pci-skeleton.o
index fa41608..cbefc79 100644 (file)
@@ -35,7 +35,7 @@ need and this same framework should make it much easier to refactor
 common code into utility functions shared by all drivers.
 
 A good example to look at as a reference is the v4l2-pci-skeleton.c
-source that is available in this directory. It is a skeleton driver for
+source that is available in samples/v4l/. It is a skeleton driver for
 a PCI capture card, and demonstrates how to use the V4L2 driver
 framework. It can be used as a template for real PCI video capture driver.
 
diff --git a/Documentation/video4linux/v4l2-pci-skeleton.c b/Documentation/video4linux/v4l2-pci-skeleton.c
deleted file mode 100644 (file)
index 79af0c0..0000000
+++ /dev/null
@@ -1,923 +0,0 @@
-/*
- * This is a V4L2 PCI Skeleton Driver. It gives an initial skeleton source
- * for use with other PCI drivers.
- *
- * This skeleton PCI driver assumes that the card has an S-Video connector as
- * input 0 and an HDMI connector as input 1.
- *
- * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
- *
- * This program is free software; you may redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
- * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
- * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-#include <linux/types.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/kmod.h>
-#include <linux/mutex.h>
-#include <linux/pci.h>
-#include <linux/interrupt.h>
-#include <linux/videodev2.h>
-#include <linux/v4l2-dv-timings.h>
-#include <media/v4l2-device.h>
-#include <media/v4l2-dev.h>
-#include <media/v4l2-ioctl.h>
-#include <media/v4l2-dv-timings.h>
-#include <media/v4l2-ctrls.h>
-#include <media/v4l2-event.h>
-#include <media/videobuf2-v4l2.h>
-#include <media/videobuf2-dma-contig.h>
-
-MODULE_DESCRIPTION("V4L2 PCI Skeleton Driver");
-MODULE_AUTHOR("Hans Verkuil");
-MODULE_LICENSE("GPL v2");
-
-/**
- * struct skeleton - All internal data for one instance of device
- * @pdev: PCI device
- * @v4l2_dev: top-level v4l2 device struct
- * @vdev: video node structure
- * @ctrl_handler: control handler structure
- * @lock: ioctl serialization mutex
- * @std: current SDTV standard
- * @timings: current HDTV timings
- * @format: current pix format
- * @input: current video input (0 = SDTV, 1 = HDTV)
- * @queue: vb2 video capture queue
- * @alloc_ctx: vb2 contiguous DMA context
- * @qlock: spinlock controlling access to buf_list and sequence
- * @buf_list: list of buffers queued for DMA
- * @sequence: frame sequence counter
- */
-struct skeleton {
-       struct pci_dev *pdev;
-       struct v4l2_device v4l2_dev;
-       struct video_device vdev;
-       struct v4l2_ctrl_handler ctrl_handler;
-       struct mutex lock;
-       v4l2_std_id std;
-       struct v4l2_dv_timings timings;
-       struct v4l2_pix_format format;
-       unsigned input;
-
-       struct vb2_queue queue;
-       struct vb2_alloc_ctx *alloc_ctx;
-
-       spinlock_t qlock;
-       struct list_head buf_list;
-       unsigned field;
-       unsigned sequence;
-};
-
-struct skel_buffer {
-       struct vb2_buffer vb;
-       struct list_head list;
-};
-
-static inline struct skel_buffer *to_skel_buffer(struct vb2_buffer *vb2)
-{
-       return container_of(vb2, struct skel_buffer, vb);
-}
-
-static const struct pci_device_id skeleton_pci_tbl[] = {
-       /* { PCI_DEVICE(PCI_VENDOR_ID_, PCI_DEVICE_ID_) }, */
-       { 0, }
-};
-MODULE_DEVICE_TABLE(pci, skeleton_pci_tbl);
-
-/*
- * HDTV: this structure has the capabilities of the HDTV receiver.
- * It is used to constrain the huge list of possible formats based
- * upon the hardware capabilities.
- */
-static const struct v4l2_dv_timings_cap skel_timings_cap = {
-       .type = V4L2_DV_BT_656_1120,
-       /* keep this initialization for compatibility with GCC < 4.4.6 */
-       .reserved = { 0 },
-       V4L2_INIT_BT_TIMINGS(
-               720, 1920,              /* min/max width */
-               480, 1080,              /* min/max height */
-               27000000, 74250000,     /* min/max pixelclock*/
-               V4L2_DV_BT_STD_CEA861,  /* Supported standards */
-               /* capabilities */
-               V4L2_DV_BT_CAP_INTERLACED | V4L2_DV_BT_CAP_PROGRESSIVE
-       )
-};
-
-/*
- * Supported SDTV standards. This does the same job as skel_timings_cap, but
- * for standard TV formats.
- */
-#define SKEL_TVNORMS V4L2_STD_ALL
-
-/*
- * Interrupt handler: typically interrupts happen after a new frame has been
- * captured. It is the job of the handler to remove the new frame from the
- * internal list and give it back to the vb2 framework, updating the sequence
- * counter, field and timestamp at the same time.
- */
-static irqreturn_t skeleton_irq(int irq, void *dev_id)
-{
-#ifdef TODO
-       struct skeleton *skel = dev_id;
-
-       /* handle interrupt */
-
-       /* Once a new frame has been captured, mark it as done like this: */
-       if (captured_new_frame) {
-               ...
-               spin_lock(&skel->qlock);
-               list_del(&new_buf->list);
-               spin_unlock(&skel->qlock);
-               v4l2_get_timestamp(&new_buf->vb.v4l2_buf.timestamp);
-               new_buf->vb.v4l2_buf.sequence = skel->sequence++;
-               new_buf->vb.v4l2_buf.field = skel->field;
-               if (skel->format.field == V4L2_FIELD_ALTERNATE) {
-                       if (skel->field == V4L2_FIELD_BOTTOM)
-                               skel->field = V4L2_FIELD_TOP;
-                       else if (skel->field == V4L2_FIELD_TOP)
-                               skel->field = V4L2_FIELD_BOTTOM;
-               }
-               vb2_buffer_done(&new_buf->vb, VB2_BUF_STATE_DONE);
-       }
-#endif
-       return IRQ_HANDLED;
-}
-
-/*
- * Setup the constraints of the queue: besides setting the number of planes
- * per buffer and the size and allocation context of each plane, it also
- * checks if sufficient buffers have been allocated. Usually 3 is a good
- * minimum number: many DMA engines need a minimum of 2 buffers in the
- * queue and you need to have another available for userspace processing.
- */
-static int queue_setup(struct vb2_queue *vq,
-                      unsigned int *nbuffers, unsigned int *nplanes,
-                      unsigned int sizes[], void *alloc_ctxs[])
-{
-       struct skeleton *skel = vb2_get_drv_priv(vq);
-
-       skel->field = skel->format.field;
-       if (skel->field == V4L2_FIELD_ALTERNATE) {
-               /*
-                * You cannot use read() with FIELD_ALTERNATE since the field
-                * information (TOP/BOTTOM) cannot be passed back to the user.
-                */
-               if (vb2_fileio_is_active(vq))
-                       return -EINVAL;
-               skel->field = V4L2_FIELD_TOP;
-       }
-
-       if (vq->num_buffers + *nbuffers < 3)
-               *nbuffers = 3 - vq->num_buffers;
-       alloc_ctxs[0] = skel->alloc_ctx;
-
-       if (*nplanes)
-               return sizes[0] < skel->format.sizeimage ? -EINVAL : 0;
-       *nplanes = 1;
-       sizes[0] = skel->format.sizeimage;
-       return 0;
-}
-
-/*
- * Prepare the buffer for queueing to the DMA engine: check and set the
- * payload size.
- */
-static int buffer_prepare(struct vb2_buffer *vb)
-{
-       struct skeleton *skel = vb2_get_drv_priv(vb->vb2_queue);
-       unsigned long size = skel->format.sizeimage;
-
-       if (vb2_plane_size(vb, 0) < size) {
-               dev_err(&skel->pdev->dev, "buffer too small (%lu < %lu)\n",
-                        vb2_plane_size(vb, 0), size);
-               return -EINVAL;
-       }
-
-       vb2_set_plane_payload(vb, 0, size);
-       return 0;
-}
-
-/*
- * Queue this buffer to the DMA engine.
- */
-static void buffer_queue(struct vb2_buffer *vb)
-{
-       struct skeleton *skel = vb2_get_drv_priv(vb->vb2_queue);
-       struct skel_buffer *buf = to_skel_buffer(vb);
-       unsigned long flags;
-
-       spin_lock_irqsave(&skel->qlock, flags);
-       list_add_tail(&buf->list, &skel->buf_list);
-
-       /* TODO: Update any DMA pointers if necessary */
-
-       spin_unlock_irqrestore(&skel->qlock, flags);
-}
-
-static void return_all_buffers(struct skeleton *skel,
-                              enum vb2_buffer_state state)
-{
-       struct skel_buffer *buf, *node;
-       unsigned long flags;
-
-       spin_lock_irqsave(&skel->qlock, flags);
-       list_for_each_entry_safe(buf, node, &skel->buf_list, list) {
-               vb2_buffer_done(&buf->vb, state);
-               list_del(&buf->list);
-       }
-       spin_unlock_irqrestore(&skel->qlock, flags);
-}
-
-/*
- * Start streaming. First check if the minimum number of buffers have been
- * queued. If not, then return -ENOBUFS and the vb2 framework will call
- * this function again the next time a buffer has been queued until enough
- * buffers are available to actually start the DMA engine.
- */
-static int start_streaming(struct vb2_queue *vq, unsigned int count)
-{
-       struct skeleton *skel = vb2_get_drv_priv(vq);
-       int ret = 0;
-
-       skel->sequence = 0;
-
-       /* TODO: start DMA */
-
-       if (ret) {
-               /*
-                * In case of an error, return all active buffers to the
-                * QUEUED state
-                */
-               return_all_buffers(skel, VB2_BUF_STATE_QUEUED);
-       }
-       return ret;
-}
-
-/*
- * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
- * and passed on to the vb2 framework marked as STATE_ERROR.
- */
-static void stop_streaming(struct vb2_queue *vq)
-{
-       struct skeleton *skel = vb2_get_drv_priv(vq);
-
-       /* TODO: stop DMA */
-
-       /* Release all active buffers */
-       return_all_buffers(skel, VB2_BUF_STATE_ERROR);
-}
-
-/*
- * The vb2 queue ops. Note that since q->lock is set we can use the standard
- * vb2_ops_wait_prepare/finish helper functions. If q->lock would be NULL,
- * then this driver would have to provide these ops.
- */
-static struct vb2_ops skel_qops = {
-       .queue_setup            = queue_setup,
-       .buf_prepare            = buffer_prepare,
-       .buf_queue              = buffer_queue,
-       .start_streaming        = start_streaming,
-       .stop_streaming         = stop_streaming,
-       .wait_prepare           = vb2_ops_wait_prepare,
-       .wait_finish            = vb2_ops_wait_finish,
-};
-
-/*
- * Required ioctl querycap. Note that the version field is prefilled with
- * the version of the kernel.
- */
-static int skeleton_querycap(struct file *file, void *priv,
-                            struct v4l2_capability *cap)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
-       strlcpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
-       snprintf(cap->bus_info, sizeof(cap->bus_info), "PCI:%s",
-                pci_name(skel->pdev));
-       cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
-                          V4L2_CAP_STREAMING;
-       cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
-       return 0;
-}
-
-/*
- * Helper function to check and correct struct v4l2_pix_format. It's used
- * not only in VIDIOC_TRY/S_FMT, but also elsewhere if changes to the SDTV
- * standard, HDTV timings or the video input would require updating the
- * current format.
- */
-static void skeleton_fill_pix_format(struct skeleton *skel,
-                                    struct v4l2_pix_format *pix)
-{
-       pix->pixelformat = V4L2_PIX_FMT_YUYV;
-       if (skel->input == 0) {
-               /* S-Video input */
-               pix->width = 720;
-               pix->height = (skel->std & V4L2_STD_525_60) ? 480 : 576;
-               pix->field = V4L2_FIELD_INTERLACED;
-               pix->colorspace = V4L2_COLORSPACE_SMPTE170M;
-       } else {
-               /* HDMI input */
-               pix->width = skel->timings.bt.width;
-               pix->height = skel->timings.bt.height;
-               if (skel->timings.bt.interlaced) {
-                       pix->field = V4L2_FIELD_ALTERNATE;
-                       pix->height /= 2;
-               } else {
-                       pix->field = V4L2_FIELD_NONE;
-               }
-               pix->colorspace = V4L2_COLORSPACE_REC709;
-       }
-
-       /*
-        * The YUYV format is four bytes for every two pixels, so bytesperline
-        * is width * 2.
-        */
-       pix->bytesperline = pix->width * 2;
-       pix->sizeimage = pix->bytesperline * pix->height;
-       pix->priv = 0;
-}
-
-static int skeleton_try_fmt_vid_cap(struct file *file, void *priv,
-                                   struct v4l2_format *f)
-{
-       struct skeleton *skel = video_drvdata(file);
-       struct v4l2_pix_format *pix = &f->fmt.pix;
-
-       /*
-        * Due to historical reasons providing try_fmt with an unsupported
-        * pixelformat will return -EINVAL for video receivers. Webcam drivers,
-        * however, will silently correct the pixelformat. Some video capture
-        * applications rely on this behavior...
-        */
-       if (pix->pixelformat != V4L2_PIX_FMT_YUYV)
-               return -EINVAL;
-       skeleton_fill_pix_format(skel, pix);
-       return 0;
-}
-
-static int skeleton_s_fmt_vid_cap(struct file *file, void *priv,
-                                 struct v4l2_format *f)
-{
-       struct skeleton *skel = video_drvdata(file);
-       int ret;
-
-       ret = skeleton_try_fmt_vid_cap(file, priv, f);
-       if (ret)
-               return ret;
-
-       /*
-        * It is not allowed to change the format while buffers for use with
-        * streaming have already been allocated.
-        */
-       if (vb2_is_busy(&skel->queue))
-               return -EBUSY;
-
-       /* TODO: change format */
-       skel->format = f->fmt.pix;
-       return 0;
-}
-
-static int skeleton_g_fmt_vid_cap(struct file *file, void *priv,
-                                 struct v4l2_format *f)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       f->fmt.pix = skel->format;
-       return 0;
-}
-
-static int skeleton_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 skeleton_s_std(struct file *file, void *priv, v4l2_std_id std)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* S_STD is not supported on the HDMI input */
-       if (skel->input)
-               return -ENODATA;
-
-       /*
-        * No change, so just return. Some applications call S_STD again after
-        * the buffers for streaming have been set up, so we have to allow for
-        * this behavior.
-        */
-       if (std == skel->std)
-               return 0;
-
-       /*
-        * Changing the standard implies a format change, which is not allowed
-        * while buffers for use with streaming have already been allocated.
-        */
-       if (vb2_is_busy(&skel->queue))
-               return -EBUSY;
-
-       /* TODO: handle changing std */
-
-       skel->std = std;
-
-       /* Update the internal format */
-       skeleton_fill_pix_format(skel, &skel->format);
-       return 0;
-}
-
-static int skeleton_g_std(struct file *file, void *priv, v4l2_std_id *std)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* G_STD is not supported on the HDMI input */
-       if (skel->input)
-               return -ENODATA;
-
-       *std = skel->std;
-       return 0;
-}
-
-/*
- * Query the current standard as seen by the hardware. This function shall
- * never actually change the standard, it just detects and reports.
- * The framework will initially set *std to tvnorms (i.e. the set of
- * supported standards by this input), and this function should just AND
- * this value. If there is no signal, then *std should be set to 0.
- */
-static int skeleton_querystd(struct file *file, void *priv, v4l2_std_id *std)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* QUERY_STD is not supported on the HDMI input */
-       if (skel->input)
-               return -ENODATA;
-
-#ifdef TODO
-       /*
-        * Query currently seen standard. Initial value of *std is
-        * V4L2_STD_ALL. This function should look something like this:
-        */
-       get_signal_info();
-       if (no_signal) {
-               *std = 0;
-               return 0;
-       }
-       /* Use signal information to reduce the number of possible standards */
-       if (signal_has_525_lines)
-               *std &= V4L2_STD_525_60;
-       else
-               *std &= V4L2_STD_625_50;
-#endif
-       return 0;
-}
-
-static int skeleton_s_dv_timings(struct file *file, void *_fh,
-                                struct v4l2_dv_timings *timings)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* S_DV_TIMINGS is not supported on the S-Video input */
-       if (skel->input == 0)
-               return -ENODATA;
-
-       /* Quick sanity check */
-       if (!v4l2_valid_dv_timings(timings, &skel_timings_cap, NULL, NULL))
-               return -EINVAL;
-
-       /* Check if the timings are part of the CEA-861 timings. */
-       if (!v4l2_find_dv_timings_cap(timings, &skel_timings_cap,
-                                     0, NULL, NULL))
-               return -EINVAL;
-
-       /* Return 0 if the new timings are the same as the current timings. */
-       if (v4l2_match_dv_timings(timings, &skel->timings, 0, false))
-               return 0;
-
-       /*
-        * Changing the timings implies a format change, which is not allowed
-        * while buffers for use with streaming have already been allocated.
-        */
-       if (vb2_is_busy(&skel->queue))
-               return -EBUSY;
-
-       /* TODO: Configure new timings */
-
-       /* Save timings */
-       skel->timings = *timings;
-
-       /* Update the internal format */
-       skeleton_fill_pix_format(skel, &skel->format);
-       return 0;
-}
-
-static int skeleton_g_dv_timings(struct file *file, void *_fh,
-                                struct v4l2_dv_timings *timings)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* G_DV_TIMINGS is not supported on the S-Video input */
-       if (skel->input == 0)
-               return -ENODATA;
-
-       *timings = skel->timings;
-       return 0;
-}
-
-static int skeleton_enum_dv_timings(struct file *file, void *_fh,
-                                   struct v4l2_enum_dv_timings *timings)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* ENUM_DV_TIMINGS is not supported on the S-Video input */
-       if (skel->input == 0)
-               return -ENODATA;
-
-       return v4l2_enum_dv_timings_cap(timings, &skel_timings_cap,
-                                       NULL, NULL);
-}
-
-/*
- * Query the current timings as seen by the hardware. This function shall
- * never actually change the timings, it just detects and reports.
- * If no signal is detected, then return -ENOLINK. If the hardware cannot
- * lock to the signal, then return -ENOLCK. If the signal is out of range
- * of the capabilities of the system (e.g., it is possible that the receiver
- * can lock but that the DMA engine it is connected to cannot handle
- * pixelclocks above a certain frequency), then -ERANGE is returned.
- */
-static int skeleton_query_dv_timings(struct file *file, void *_fh,
-                                    struct v4l2_dv_timings *timings)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* QUERY_DV_TIMINGS is not supported on the S-Video input */
-       if (skel->input == 0)
-               return -ENODATA;
-
-#ifdef TODO
-       /*
-        * Query currently seen timings. This function should look
-        * something like this:
-        */
-       detect_timings();
-       if (no_signal)
-               return -ENOLINK;
-       if (cannot_lock_to_signal)
-               return -ENOLCK;
-       if (signal_out_of_range_of_capabilities)
-               return -ERANGE;
-
-       /* Useful for debugging */
-       v4l2_print_dv_timings(skel->v4l2_dev.name, "query_dv_timings:",
-                       timings, true);
-#endif
-       return 0;
-}
-
-static int skeleton_dv_timings_cap(struct file *file, void *fh,
-                                  struct v4l2_dv_timings_cap *cap)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       /* DV_TIMINGS_CAP is not supported on the S-Video input */
-       if (skel->input == 0)
-               return -ENODATA;
-       *cap = skel_timings_cap;
-       return 0;
-}
-
-static int skeleton_enum_input(struct file *file, void *priv,
-                              struct v4l2_input *i)
-{
-       if (i->index > 1)
-               return -EINVAL;
-
-       i->type = V4L2_INPUT_TYPE_CAMERA;
-       if (i->index == 0) {
-               i->std = SKEL_TVNORMS;
-               strlcpy(i->name, "S-Video", sizeof(i->name));
-               i->capabilities = V4L2_IN_CAP_STD;
-       } else {
-               i->std = 0;
-               strlcpy(i->name, "HDMI", sizeof(i->name));
-               i->capabilities = V4L2_IN_CAP_DV_TIMINGS;
-       }
-       return 0;
-}
-
-static int skeleton_s_input(struct file *file, void *priv, unsigned int i)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       if (i > 1)
-               return -EINVAL;
-
-       /*
-        * Changing the input implies a format change, which is not allowed
-        * while buffers for use with streaming have already been allocated.
-        */
-       if (vb2_is_busy(&skel->queue))
-               return -EBUSY;
-
-       skel->input = i;
-       /*
-        * Update tvnorms. The tvnorms value is used by the core to implement
-        * VIDIOC_ENUMSTD so it has to be correct. If tvnorms == 0, then
-        * ENUMSTD will return -ENODATA.
-        */
-       skel->vdev.tvnorms = i ? 0 : SKEL_TVNORMS;
-
-       /* Update the internal format */
-       skeleton_fill_pix_format(skel, &skel->format);
-       return 0;
-}
-
-static int skeleton_g_input(struct file *file, void *priv, unsigned int *i)
-{
-       struct skeleton *skel = video_drvdata(file);
-
-       *i = skel->input;
-       return 0;
-}
-
-/* The control handler. */
-static int skeleton_s_ctrl(struct v4l2_ctrl *ctrl)
-{
-       /*struct skeleton *skel =
-               container_of(ctrl->handler, struct skeleton, ctrl_handler);*/
-
-       switch (ctrl->id) {
-       case V4L2_CID_BRIGHTNESS:
-               /* TODO: set brightness to ctrl->val */
-               break;
-       case V4L2_CID_CONTRAST:
-               /* TODO: set contrast to ctrl->val */
-               break;
-       case V4L2_CID_SATURATION:
-               /* TODO: set saturation to ctrl->val */
-               break;
-       case V4L2_CID_HUE:
-               /* TODO: set hue to ctrl->val */
-               break;
-       default:
-               return -EINVAL;
-       }
-       return 0;
-}
-
-/* ------------------------------------------------------------------
-       File operations for the device
-   ------------------------------------------------------------------*/
-
-static const struct v4l2_ctrl_ops skel_ctrl_ops = {
-       .s_ctrl = skeleton_s_ctrl,
-};
-
-/*
- * The set of all supported ioctls. Note that all the streaming ioctls
- * use the vb2 helper functions that take care of all the locking and
- * that also do ownership tracking (i.e. only the filehandle that requested
- * the buffers can call the streaming ioctls, all other filehandles will
- * receive -EBUSY if they attempt to call the same streaming ioctls).
- *
- * The last three ioctls also use standard helper functions: these implement
- * standard behavior for drivers with controls.
- */
-static const struct v4l2_ioctl_ops skel_ioctl_ops = {
-       .vidioc_querycap = skeleton_querycap,
-       .vidioc_try_fmt_vid_cap = skeleton_try_fmt_vid_cap,
-       .vidioc_s_fmt_vid_cap = skeleton_s_fmt_vid_cap,
-       .vidioc_g_fmt_vid_cap = skeleton_g_fmt_vid_cap,
-       .vidioc_enum_fmt_vid_cap = skeleton_enum_fmt_vid_cap,
-
-       .vidioc_g_std = skeleton_g_std,
-       .vidioc_s_std = skeleton_s_std,
-       .vidioc_querystd = skeleton_querystd,
-
-       .vidioc_s_dv_timings = skeleton_s_dv_timings,
-       .vidioc_g_dv_timings = skeleton_g_dv_timings,
-       .vidioc_enum_dv_timings = skeleton_enum_dv_timings,
-       .vidioc_query_dv_timings = skeleton_query_dv_timings,
-       .vidioc_dv_timings_cap = skeleton_dv_timings_cap,
-
-       .vidioc_enum_input = skeleton_enum_input,
-       .vidioc_g_input = skeleton_g_input,
-       .vidioc_s_input = skeleton_s_input,
-
-       .vidioc_reqbufs = vb2_ioctl_reqbufs,
-       .vidioc_create_bufs = vb2_ioctl_create_bufs,
-       .vidioc_querybuf = vb2_ioctl_querybuf,
-       .vidioc_qbuf = vb2_ioctl_qbuf,
-       .vidioc_dqbuf = vb2_ioctl_dqbuf,
-       .vidioc_expbuf = vb2_ioctl_expbuf,
-       .vidioc_streamon = vb2_ioctl_streamon,
-       .vidioc_streamoff = vb2_ioctl_streamoff,
-
-       .vidioc_log_status = v4l2_ctrl_log_status,
-       .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
-       .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
-};
-
-/*
- * The set of file operations. Note that all these ops are standard core
- * helper functions.
- */
-static const struct v4l2_file_operations skel_fops = {
-       .owner = THIS_MODULE,
-       .open = v4l2_fh_open,
-       .release = vb2_fop_release,
-       .unlocked_ioctl = video_ioctl2,
-       .read = vb2_fop_read,
-       .mmap = vb2_fop_mmap,
-       .poll = vb2_fop_poll,
-};
-
-/*
- * The initial setup of this device instance. Note that the initial state of
- * the driver should be complete. So the initial format, standard, timings
- * and video input should all be initialized to some reasonable value.
- */
-static int skeleton_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
-{
-       /* The initial timings are chosen to be 720p60. */
-       static const struct v4l2_dv_timings timings_def =
-               V4L2_DV_BT_CEA_1280X720P60;
-       struct skeleton *skel;
-       struct video_device *vdev;
-       struct v4l2_ctrl_handler *hdl;
-       struct vb2_queue *q;
-       int ret;
-
-       /* Enable PCI */
-       ret = pci_enable_device(pdev);
-       if (ret)
-               return ret;
-       ret = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
-       if (ret) {
-               dev_err(&pdev->dev, "no suitable DMA available.\n");
-               goto disable_pci;
-       }
-
-       /* Allocate a new instance */
-       skel = devm_kzalloc(&pdev->dev, sizeof(struct skeleton), GFP_KERNEL);
-       if (!skel)
-               return -ENOMEM;
-
-       /* Allocate the interrupt */
-       ret = devm_request_irq(&pdev->dev, pdev->irq,
-                              skeleton_irq, 0, KBUILD_MODNAME, skel);
-       if (ret) {
-               dev_err(&pdev->dev, "request_irq failed\n");
-               goto disable_pci;
-       }
-       skel->pdev = pdev;
-
-       /* Fill in the initial format-related settings */
-       skel->timings = timings_def;
-       skel->std = V4L2_STD_625_50;
-       skeleton_fill_pix_format(skel, &skel->format);
-
-       /* Initialize the top-level structure */
-       ret = v4l2_device_register(&pdev->dev, &skel->v4l2_dev);
-       if (ret)
-               goto disable_pci;
-
-       mutex_init(&skel->lock);
-
-       /* Add the controls */
-       hdl = &skel->ctrl_handler;
-       v4l2_ctrl_handler_init(hdl, 4);
-       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
-                         V4L2_CID_BRIGHTNESS, 0, 255, 1, 127);
-       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
-                         V4L2_CID_CONTRAST, 0, 255, 1, 16);
-       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
-                         V4L2_CID_SATURATION, 0, 255, 1, 127);
-       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
-                         V4L2_CID_HUE, -128, 127, 1, 0);
-       if (hdl->error) {
-               ret = hdl->error;
-               goto free_hdl;
-       }
-       skel->v4l2_dev.ctrl_handler = hdl;
-
-       /* Initialize the vb2 queue */
-       q = &skel->queue;
-       q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-       q->io_modes = VB2_MMAP | VB2_DMABUF | VB2_READ;
-       q->drv_priv = skel;
-       q->buf_struct_size = sizeof(struct skel_buffer);
-       q->ops = &skel_qops;
-       q->mem_ops = &vb2_dma_contig_memops;
-       q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
-       /*
-        * Assume that this DMA engine needs to have at least two buffers
-        * available before it can be started. The start_streaming() op
-        * won't be called until at least this many buffers are queued up.
-        */
-       q->min_buffers_needed = 2;
-       /*
-        * The serialization lock for the streaming ioctls. This is the same
-        * as the main serialization lock, but if some of the non-streaming
-        * ioctls could take a long time to execute, then you might want to
-        * have a different lock here to prevent VIDIOC_DQBUF from being
-        * blocked while waiting for another action to finish. This is
-        * generally not needed for PCI devices, but USB devices usually do
-        * want a separate lock here.
-        */
-       q->lock = &skel->lock;
-       /*
-        * Since this driver can only do 32-bit DMA we must make sure that
-        * the vb2 core will allocate the buffers in 32-bit DMA memory.
-        */
-       q->gfp_flags = GFP_DMA32;
-       ret = vb2_queue_init(q);
-       if (ret)
-               goto free_hdl;
-
-       skel->alloc_ctx = vb2_dma_contig_init_ctx(&pdev->dev);
-       if (IS_ERR(skel->alloc_ctx)) {
-               dev_err(&pdev->dev, "Can't allocate buffer context");
-               ret = PTR_ERR(skel->alloc_ctx);
-               goto free_hdl;
-       }
-       INIT_LIST_HEAD(&skel->buf_list);
-       spin_lock_init(&skel->qlock);
-
-       /* Initialize the video_device structure */
-       vdev = &skel->vdev;
-       strlcpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
-       /*
-        * There is nothing to clean up, so release is set to an empty release
-        * function. The release callback must be non-NULL.
-        */
-       vdev->release = video_device_release_empty;
-       vdev->fops = &skel_fops,
-       vdev->ioctl_ops = &skel_ioctl_ops,
-       /*
-        * The main serialization lock. All ioctls are serialized by this
-        * lock. Exception: if q->lock is set, then the streaming ioctls
-        * are serialized by that separate lock.
-        */
-       vdev->lock = &skel->lock;
-       vdev->queue = q;
-       vdev->v4l2_dev = &skel->v4l2_dev;
-       /* Supported SDTV standards, if any */
-       vdev->tvnorms = SKEL_TVNORMS;
-       video_set_drvdata(vdev, skel);
-
-       ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
-       if (ret)
-               goto free_ctx;
-
-       dev_info(&pdev->dev, "V4L2 PCI Skeleton Driver loaded\n");
-       return 0;
-
-free_ctx:
-       vb2_dma_contig_cleanup_ctx(skel->alloc_ctx);
-free_hdl:
-       v4l2_ctrl_handler_free(&skel->ctrl_handler);
-       v4l2_device_unregister(&skel->v4l2_dev);
-disable_pci:
-       pci_disable_device(pdev);
-       return ret;
-}
-
-static void skeleton_remove(struct pci_dev *pdev)
-{
-       struct v4l2_device *v4l2_dev = pci_get_drvdata(pdev);
-       struct skeleton *skel = container_of(v4l2_dev, struct skeleton, v4l2_dev);
-
-       video_unregister_device(&skel->vdev);
-       v4l2_ctrl_handler_free(&skel->ctrl_handler);
-       vb2_dma_contig_cleanup_ctx(skel->alloc_ctx);
-       v4l2_device_unregister(&skel->v4l2_dev);
-       pci_disable_device(skel->pdev);
-}
-
-static struct pci_driver skeleton_driver = {
-       .name = KBUILD_MODNAME,
-       .probe = skeleton_probe,
-       .remove = skeleton_remove,
-       .id_table = skeleton_pci_tbl,
-};
-
-module_pci_driver(skeleton_driver);
index 594ef7d..2e3b523 100644 (file)
@@ -2,4 +2,4 @@
 
 obj-$(CONFIG_SAMPLES)  += kobject/ kprobes/ trace_events/ livepatch/ \
                           hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ \
-                          configfs/ connector/
+                          configfs/ connector/ v4l/
diff --git a/samples/v4l/Makefile b/samples/v4l/Makefile
new file mode 100644 (file)
index 0000000..65a351d
--- /dev/null
@@ -0,0 +1 @@
+obj-$(CONFIG_VIDEO_PCI_SKELETON) := v4l2-pci-skeleton.o
diff --git a/samples/v4l/v4l2-pci-skeleton.c b/samples/v4l/v4l2-pci-skeleton.c
new file mode 100644 (file)
index 0000000..79af0c0
--- /dev/null
@@ -0,0 +1,923 @@
+/*
+ * This is a V4L2 PCI Skeleton Driver. It gives an initial skeleton source
+ * for use with other PCI drivers.
+ *
+ * This skeleton PCI driver assumes that the card has an S-Video connector as
+ * input 0 and an HDMI connector as input 1.
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/videodev2.h>
+#include <linux/v4l2-dv-timings.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-dv-timings.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-dma-contig.h>
+
+MODULE_DESCRIPTION("V4L2 PCI Skeleton Driver");
+MODULE_AUTHOR("Hans Verkuil");
+MODULE_LICENSE("GPL v2");
+
+/**
+ * struct skeleton - All internal data for one instance of device
+ * @pdev: PCI device
+ * @v4l2_dev: top-level v4l2 device struct
+ * @vdev: video node structure
+ * @ctrl_handler: control handler structure
+ * @lock: ioctl serialization mutex
+ * @std: current SDTV standard
+ * @timings: current HDTV timings
+ * @format: current pix format
+ * @input: current video input (0 = SDTV, 1 = HDTV)
+ * @queue: vb2 video capture queue
+ * @alloc_ctx: vb2 contiguous DMA context
+ * @qlock: spinlock controlling access to buf_list and sequence
+ * @buf_list: list of buffers queued for DMA
+ * @sequence: frame sequence counter
+ */
+struct skeleton {
+       struct pci_dev *pdev;
+       struct v4l2_device v4l2_dev;
+       struct video_device vdev;
+       struct v4l2_ctrl_handler ctrl_handler;
+       struct mutex lock;
+       v4l2_std_id std;
+       struct v4l2_dv_timings timings;
+       struct v4l2_pix_format format;
+       unsigned input;
+
+       struct vb2_queue queue;
+       struct vb2_alloc_ctx *alloc_ctx;
+
+       spinlock_t qlock;
+       struct list_head buf_list;
+       unsigned field;
+       unsigned sequence;
+};
+
+struct skel_buffer {
+       struct vb2_buffer vb;
+       struct list_head list;
+};
+
+static inline struct skel_buffer *to_skel_buffer(struct vb2_buffer *vb2)
+{
+       return container_of(vb2, struct skel_buffer, vb);
+}
+
+static const struct pci_device_id skeleton_pci_tbl[] = {
+       /* { PCI_DEVICE(PCI_VENDOR_ID_, PCI_DEVICE_ID_) }, */
+       { 0, }
+};
+MODULE_DEVICE_TABLE(pci, skeleton_pci_tbl);
+
+/*
+ * HDTV: this structure has the capabilities of the HDTV receiver.
+ * It is used to constrain the huge list of possible formats based
+ * upon the hardware capabilities.
+ */
+static const struct v4l2_dv_timings_cap skel_timings_cap = {
+       .type = V4L2_DV_BT_656_1120,
+       /* keep this initialization for compatibility with GCC < 4.4.6 */
+       .reserved = { 0 },
+       V4L2_INIT_BT_TIMINGS(
+               720, 1920,              /* min/max width */
+               480, 1080,              /* min/max height */
+               27000000, 74250000,     /* min/max pixelclock*/
+               V4L2_DV_BT_STD_CEA861,  /* Supported standards */
+               /* capabilities */
+               V4L2_DV_BT_CAP_INTERLACED | V4L2_DV_BT_CAP_PROGRESSIVE
+       )
+};
+
+/*
+ * Supported SDTV standards. This does the same job as skel_timings_cap, but
+ * for standard TV formats.
+ */
+#define SKEL_TVNORMS V4L2_STD_ALL
+
+/*
+ * Interrupt handler: typically interrupts happen after a new frame has been
+ * captured. It is the job of the handler to remove the new frame from the
+ * internal list and give it back to the vb2 framework, updating the sequence
+ * counter, field and timestamp at the same time.
+ */
+static irqreturn_t skeleton_irq(int irq, void *dev_id)
+{
+#ifdef TODO
+       struct skeleton *skel = dev_id;
+
+       /* handle interrupt */
+
+       /* Once a new frame has been captured, mark it as done like this: */
+       if (captured_new_frame) {
+               ...
+               spin_lock(&skel->qlock);
+               list_del(&new_buf->list);
+               spin_unlock(&skel->qlock);
+               v4l2_get_timestamp(&new_buf->vb.v4l2_buf.timestamp);
+               new_buf->vb.v4l2_buf.sequence = skel->sequence++;
+               new_buf->vb.v4l2_buf.field = skel->field;
+               if (skel->format.field == V4L2_FIELD_ALTERNATE) {
+                       if (skel->field == V4L2_FIELD_BOTTOM)
+                               skel->field = V4L2_FIELD_TOP;
+                       else if (skel->field == V4L2_FIELD_TOP)
+                               skel->field = V4L2_FIELD_BOTTOM;
+               }
+               vb2_buffer_done(&new_buf->vb, VB2_BUF_STATE_DONE);
+       }
+#endif
+       return IRQ_HANDLED;
+}
+
+/*
+ * Setup the constraints of the queue: besides setting the number of planes
+ * per buffer and the size and allocation context of each plane, it also
+ * checks if sufficient buffers have been allocated. Usually 3 is a good
+ * minimum number: many DMA engines need a minimum of 2 buffers in the
+ * queue and you need to have another available for userspace processing.
+ */
+static int queue_setup(struct vb2_queue *vq,
+                      unsigned int *nbuffers, unsigned int *nplanes,
+                      unsigned int sizes[], void *alloc_ctxs[])
+{
+       struct skeleton *skel = vb2_get_drv_priv(vq);
+
+       skel->field = skel->format.field;
+       if (skel->field == V4L2_FIELD_ALTERNATE) {
+               /*
+                * You cannot use read() with FIELD_ALTERNATE since the field
+                * information (TOP/BOTTOM) cannot be passed back to the user.
+                */
+               if (vb2_fileio_is_active(vq))
+                       return -EINVAL;
+               skel->field = V4L2_FIELD_TOP;
+       }
+
+       if (vq->num_buffers + *nbuffers < 3)
+               *nbuffers = 3 - vq->num_buffers;
+       alloc_ctxs[0] = skel->alloc_ctx;
+
+       if (*nplanes)
+               return sizes[0] < skel->format.sizeimage ? -EINVAL : 0;
+       *nplanes = 1;
+       sizes[0] = skel->format.sizeimage;
+       return 0;
+}
+
+/*
+ * Prepare the buffer for queueing to the DMA engine: check and set the
+ * payload size.
+ */
+static int buffer_prepare(struct vb2_buffer *vb)
+{
+       struct skeleton *skel = vb2_get_drv_priv(vb->vb2_queue);
+       unsigned long size = skel->format.sizeimage;
+
+       if (vb2_plane_size(vb, 0) < size) {
+               dev_err(&skel->pdev->dev, "buffer too small (%lu < %lu)\n",
+                        vb2_plane_size(vb, 0), size);
+               return -EINVAL;
+       }
+
+       vb2_set_plane_payload(vb, 0, size);
+       return 0;
+}
+
+/*
+ * Queue this buffer to the DMA engine.
+ */
+static void buffer_queue(struct vb2_buffer *vb)
+{
+       struct skeleton *skel = vb2_get_drv_priv(vb->vb2_queue);
+       struct skel_buffer *buf = to_skel_buffer(vb);
+       unsigned long flags;
+
+       spin_lock_irqsave(&skel->qlock, flags);
+       list_add_tail(&buf->list, &skel->buf_list);
+
+       /* TODO: Update any DMA pointers if necessary */
+
+       spin_unlock_irqrestore(&skel->qlock, flags);
+}
+
+static void return_all_buffers(struct skeleton *skel,
+                              enum vb2_buffer_state state)
+{
+       struct skel_buffer *buf, *node;
+       unsigned long flags;
+
+       spin_lock_irqsave(&skel->qlock, flags);
+       list_for_each_entry_safe(buf, node, &skel->buf_list, list) {
+               vb2_buffer_done(&buf->vb, state);
+               list_del(&buf->list);
+       }
+       spin_unlock_irqrestore(&skel->qlock, flags);
+}
+
+/*
+ * Start streaming. First check if the minimum number of buffers have been
+ * queued. If not, then return -ENOBUFS and the vb2 framework will call
+ * this function again the next time a buffer has been queued until enough
+ * buffers are available to actually start the DMA engine.
+ */
+static int start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+       struct skeleton *skel = vb2_get_drv_priv(vq);
+       int ret = 0;
+
+       skel->sequence = 0;
+
+       /* TODO: start DMA */
+
+       if (ret) {
+               /*
+                * In case of an error, return all active buffers to the
+                * QUEUED state
+                */
+               return_all_buffers(skel, VB2_BUF_STATE_QUEUED);
+       }
+       return ret;
+}
+
+/*
+ * Stop the DMA engine. Any remaining buffers in the DMA queue are dequeued
+ * and passed on to the vb2 framework marked as STATE_ERROR.
+ */
+static void stop_streaming(struct vb2_queue *vq)
+{
+       struct skeleton *skel = vb2_get_drv_priv(vq);
+
+       /* TODO: stop DMA */
+
+       /* Release all active buffers */
+       return_all_buffers(skel, VB2_BUF_STATE_ERROR);
+}
+
+/*
+ * The vb2 queue ops. Note that since q->lock is set we can use the standard
+ * vb2_ops_wait_prepare/finish helper functions. If q->lock would be NULL,
+ * then this driver would have to provide these ops.
+ */
+static struct vb2_ops skel_qops = {
+       .queue_setup            = queue_setup,
+       .buf_prepare            = buffer_prepare,
+       .buf_queue              = buffer_queue,
+       .start_streaming        = start_streaming,
+       .stop_streaming         = stop_streaming,
+       .wait_prepare           = vb2_ops_wait_prepare,
+       .wait_finish            = vb2_ops_wait_finish,
+};
+
+/*
+ * Required ioctl querycap. Note that the version field is prefilled with
+ * the version of the kernel.
+ */
+static int skeleton_querycap(struct file *file, void *priv,
+                            struct v4l2_capability *cap)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
+       strlcpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
+       snprintf(cap->bus_info, sizeof(cap->bus_info), "PCI:%s",
+                pci_name(skel->pdev));
+       cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
+                          V4L2_CAP_STREAMING;
+       cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
+       return 0;
+}
+
+/*
+ * Helper function to check and correct struct v4l2_pix_format. It's used
+ * not only in VIDIOC_TRY/S_FMT, but also elsewhere if changes to the SDTV
+ * standard, HDTV timings or the video input would require updating the
+ * current format.
+ */
+static void skeleton_fill_pix_format(struct skeleton *skel,
+                                    struct v4l2_pix_format *pix)
+{
+       pix->pixelformat = V4L2_PIX_FMT_YUYV;
+       if (skel->input == 0) {
+               /* S-Video input */
+               pix->width = 720;
+               pix->height = (skel->std & V4L2_STD_525_60) ? 480 : 576;
+               pix->field = V4L2_FIELD_INTERLACED;
+               pix->colorspace = V4L2_COLORSPACE_SMPTE170M;
+       } else {
+               /* HDMI input */
+               pix->width = skel->timings.bt.width;
+               pix->height = skel->timings.bt.height;
+               if (skel->timings.bt.interlaced) {
+                       pix->field = V4L2_FIELD_ALTERNATE;
+                       pix->height /= 2;
+               } else {
+                       pix->field = V4L2_FIELD_NONE;
+               }
+               pix->colorspace = V4L2_COLORSPACE_REC709;
+       }
+
+       /*
+        * The YUYV format is four bytes for every two pixels, so bytesperline
+        * is width * 2.
+        */
+       pix->bytesperline = pix->width * 2;
+       pix->sizeimage = pix->bytesperline * pix->height;
+       pix->priv = 0;
+}
+
+static int skeleton_try_fmt_vid_cap(struct file *file, void *priv,
+                                   struct v4l2_format *f)
+{
+       struct skeleton *skel = video_drvdata(file);
+       struct v4l2_pix_format *pix = &f->fmt.pix;
+
+       /*
+        * Due to historical reasons providing try_fmt with an unsupported
+        * pixelformat will return -EINVAL for video receivers. Webcam drivers,
+        * however, will silently correct the pixelformat. Some video capture
+        * applications rely on this behavior...
+        */
+       if (pix->pixelformat != V4L2_PIX_FMT_YUYV)
+               return -EINVAL;
+       skeleton_fill_pix_format(skel, pix);
+       return 0;
+}
+
+static int skeleton_s_fmt_vid_cap(struct file *file, void *priv,
+                                 struct v4l2_format *f)
+{
+       struct skeleton *skel = video_drvdata(file);
+       int ret;
+
+       ret = skeleton_try_fmt_vid_cap(file, priv, f);
+       if (ret)
+               return ret;
+
+       /*
+        * It is not allowed to change the format while buffers for use with
+        * streaming have already been allocated.
+        */
+       if (vb2_is_busy(&skel->queue))
+               return -EBUSY;
+
+       /* TODO: change format */
+       skel->format = f->fmt.pix;
+       return 0;
+}
+
+static int skeleton_g_fmt_vid_cap(struct file *file, void *priv,
+                                 struct v4l2_format *f)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       f->fmt.pix = skel->format;
+       return 0;
+}
+
+static int skeleton_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 skeleton_s_std(struct file *file, void *priv, v4l2_std_id std)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* S_STD is not supported on the HDMI input */
+       if (skel->input)
+               return -ENODATA;
+
+       /*
+        * No change, so just return. Some applications call S_STD again after
+        * the buffers for streaming have been set up, so we have to allow for
+        * this behavior.
+        */
+       if (std == skel->std)
+               return 0;
+
+       /*
+        * Changing the standard implies a format change, which is not allowed
+        * while buffers for use with streaming have already been allocated.
+        */
+       if (vb2_is_busy(&skel->queue))
+               return -EBUSY;
+
+       /* TODO: handle changing std */
+
+       skel->std = std;
+
+       /* Update the internal format */
+       skeleton_fill_pix_format(skel, &skel->format);
+       return 0;
+}
+
+static int skeleton_g_std(struct file *file, void *priv, v4l2_std_id *std)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* G_STD is not supported on the HDMI input */
+       if (skel->input)
+               return -ENODATA;
+
+       *std = skel->std;
+       return 0;
+}
+
+/*
+ * Query the current standard as seen by the hardware. This function shall
+ * never actually change the standard, it just detects and reports.
+ * The framework will initially set *std to tvnorms (i.e. the set of
+ * supported standards by this input), and this function should just AND
+ * this value. If there is no signal, then *std should be set to 0.
+ */
+static int skeleton_querystd(struct file *file, void *priv, v4l2_std_id *std)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* QUERY_STD is not supported on the HDMI input */
+       if (skel->input)
+               return -ENODATA;
+
+#ifdef TODO
+       /*
+        * Query currently seen standard. Initial value of *std is
+        * V4L2_STD_ALL. This function should look something like this:
+        */
+       get_signal_info();
+       if (no_signal) {
+               *std = 0;
+               return 0;
+       }
+       /* Use signal information to reduce the number of possible standards */
+       if (signal_has_525_lines)
+               *std &= V4L2_STD_525_60;
+       else
+               *std &= V4L2_STD_625_50;
+#endif
+       return 0;
+}
+
+static int skeleton_s_dv_timings(struct file *file, void *_fh,
+                                struct v4l2_dv_timings *timings)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* S_DV_TIMINGS is not supported on the S-Video input */
+       if (skel->input == 0)
+               return -ENODATA;
+
+       /* Quick sanity check */
+       if (!v4l2_valid_dv_timings(timings, &skel_timings_cap, NULL, NULL))
+               return -EINVAL;
+
+       /* Check if the timings are part of the CEA-861 timings. */
+       if (!v4l2_find_dv_timings_cap(timings, &skel_timings_cap,
+                                     0, NULL, NULL))
+               return -EINVAL;
+
+       /* Return 0 if the new timings are the same as the current timings. */
+       if (v4l2_match_dv_timings(timings, &skel->timings, 0, false))
+               return 0;
+
+       /*
+        * Changing the timings implies a format change, which is not allowed
+        * while buffers for use with streaming have already been allocated.
+        */
+       if (vb2_is_busy(&skel->queue))
+               return -EBUSY;
+
+       /* TODO: Configure new timings */
+
+       /* Save timings */
+       skel->timings = *timings;
+
+       /* Update the internal format */
+       skeleton_fill_pix_format(skel, &skel->format);
+       return 0;
+}
+
+static int skeleton_g_dv_timings(struct file *file, void *_fh,
+                                struct v4l2_dv_timings *timings)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* G_DV_TIMINGS is not supported on the S-Video input */
+       if (skel->input == 0)
+               return -ENODATA;
+
+       *timings = skel->timings;
+       return 0;
+}
+
+static int skeleton_enum_dv_timings(struct file *file, void *_fh,
+                                   struct v4l2_enum_dv_timings *timings)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* ENUM_DV_TIMINGS is not supported on the S-Video input */
+       if (skel->input == 0)
+               return -ENODATA;
+
+       return v4l2_enum_dv_timings_cap(timings, &skel_timings_cap,
+                                       NULL, NULL);
+}
+
+/*
+ * Query the current timings as seen by the hardware. This function shall
+ * never actually change the timings, it just detects and reports.
+ * If no signal is detected, then return -ENOLINK. If the hardware cannot
+ * lock to the signal, then return -ENOLCK. If the signal is out of range
+ * of the capabilities of the system (e.g., it is possible that the receiver
+ * can lock but that the DMA engine it is connected to cannot handle
+ * pixelclocks above a certain frequency), then -ERANGE is returned.
+ */
+static int skeleton_query_dv_timings(struct file *file, void *_fh,
+                                    struct v4l2_dv_timings *timings)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* QUERY_DV_TIMINGS is not supported on the S-Video input */
+       if (skel->input == 0)
+               return -ENODATA;
+
+#ifdef TODO
+       /*
+        * Query currently seen timings. This function should look
+        * something like this:
+        */
+       detect_timings();
+       if (no_signal)
+               return -ENOLINK;
+       if (cannot_lock_to_signal)
+               return -ENOLCK;
+       if (signal_out_of_range_of_capabilities)
+               return -ERANGE;
+
+       /* Useful for debugging */
+       v4l2_print_dv_timings(skel->v4l2_dev.name, "query_dv_timings:",
+                       timings, true);
+#endif
+       return 0;
+}
+
+static int skeleton_dv_timings_cap(struct file *file, void *fh,
+                                  struct v4l2_dv_timings_cap *cap)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       /* DV_TIMINGS_CAP is not supported on the S-Video input */
+       if (skel->input == 0)
+               return -ENODATA;
+       *cap = skel_timings_cap;
+       return 0;
+}
+
+static int skeleton_enum_input(struct file *file, void *priv,
+                              struct v4l2_input *i)
+{
+       if (i->index > 1)
+               return -EINVAL;
+
+       i->type = V4L2_INPUT_TYPE_CAMERA;
+       if (i->index == 0) {
+               i->std = SKEL_TVNORMS;
+               strlcpy(i->name, "S-Video", sizeof(i->name));
+               i->capabilities = V4L2_IN_CAP_STD;
+       } else {
+               i->std = 0;
+               strlcpy(i->name, "HDMI", sizeof(i->name));
+               i->capabilities = V4L2_IN_CAP_DV_TIMINGS;
+       }
+       return 0;
+}
+
+static int skeleton_s_input(struct file *file, void *priv, unsigned int i)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       if (i > 1)
+               return -EINVAL;
+
+       /*
+        * Changing the input implies a format change, which is not allowed
+        * while buffers for use with streaming have already been allocated.
+        */
+       if (vb2_is_busy(&skel->queue))
+               return -EBUSY;
+
+       skel->input = i;
+       /*
+        * Update tvnorms. The tvnorms value is used by the core to implement
+        * VIDIOC_ENUMSTD so it has to be correct. If tvnorms == 0, then
+        * ENUMSTD will return -ENODATA.
+        */
+       skel->vdev.tvnorms = i ? 0 : SKEL_TVNORMS;
+
+       /* Update the internal format */
+       skeleton_fill_pix_format(skel, &skel->format);
+       return 0;
+}
+
+static int skeleton_g_input(struct file *file, void *priv, unsigned int *i)
+{
+       struct skeleton *skel = video_drvdata(file);
+
+       *i = skel->input;
+       return 0;
+}
+
+/* The control handler. */
+static int skeleton_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+       /*struct skeleton *skel =
+               container_of(ctrl->handler, struct skeleton, ctrl_handler);*/
+
+       switch (ctrl->id) {
+       case V4L2_CID_BRIGHTNESS:
+               /* TODO: set brightness to ctrl->val */
+               break;
+       case V4L2_CID_CONTRAST:
+               /* TODO: set contrast to ctrl->val */
+               break;
+       case V4L2_CID_SATURATION:
+               /* TODO: set saturation to ctrl->val */
+               break;
+       case V4L2_CID_HUE:
+               /* TODO: set hue to ctrl->val */
+               break;
+       default:
+               return -EINVAL;
+       }
+       return 0;
+}
+
+/* ------------------------------------------------------------------
+       File operations for the device
+   ------------------------------------------------------------------*/
+
+static const struct v4l2_ctrl_ops skel_ctrl_ops = {
+       .s_ctrl = skeleton_s_ctrl,
+};
+
+/*
+ * The set of all supported ioctls. Note that all the streaming ioctls
+ * use the vb2 helper functions that take care of all the locking and
+ * that also do ownership tracking (i.e. only the filehandle that requested
+ * the buffers can call the streaming ioctls, all other filehandles will
+ * receive -EBUSY if they attempt to call the same streaming ioctls).
+ *
+ * The last three ioctls also use standard helper functions: these implement
+ * standard behavior for drivers with controls.
+ */
+static const struct v4l2_ioctl_ops skel_ioctl_ops = {
+       .vidioc_querycap = skeleton_querycap,
+       .vidioc_try_fmt_vid_cap = skeleton_try_fmt_vid_cap,
+       .vidioc_s_fmt_vid_cap = skeleton_s_fmt_vid_cap,
+       .vidioc_g_fmt_vid_cap = skeleton_g_fmt_vid_cap,
+       .vidioc_enum_fmt_vid_cap = skeleton_enum_fmt_vid_cap,
+
+       .vidioc_g_std = skeleton_g_std,
+       .vidioc_s_std = skeleton_s_std,
+       .vidioc_querystd = skeleton_querystd,
+
+       .vidioc_s_dv_timings = skeleton_s_dv_timings,
+       .vidioc_g_dv_timings = skeleton_g_dv_timings,
+       .vidioc_enum_dv_timings = skeleton_enum_dv_timings,
+       .vidioc_query_dv_timings = skeleton_query_dv_timings,
+       .vidioc_dv_timings_cap = skeleton_dv_timings_cap,
+
+       .vidioc_enum_input = skeleton_enum_input,
+       .vidioc_g_input = skeleton_g_input,
+       .vidioc_s_input = skeleton_s_input,
+
+       .vidioc_reqbufs = vb2_ioctl_reqbufs,
+       .vidioc_create_bufs = vb2_ioctl_create_bufs,
+       .vidioc_querybuf = vb2_ioctl_querybuf,
+       .vidioc_qbuf = vb2_ioctl_qbuf,
+       .vidioc_dqbuf = vb2_ioctl_dqbuf,
+       .vidioc_expbuf = vb2_ioctl_expbuf,
+       .vidioc_streamon = vb2_ioctl_streamon,
+       .vidioc_streamoff = vb2_ioctl_streamoff,
+
+       .vidioc_log_status = v4l2_ctrl_log_status,
+       .vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
+       .vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+};
+
+/*
+ * The set of file operations. Note that all these ops are standard core
+ * helper functions.
+ */
+static const struct v4l2_file_operations skel_fops = {
+       .owner = THIS_MODULE,
+       .open = v4l2_fh_open,
+       .release = vb2_fop_release,
+       .unlocked_ioctl = video_ioctl2,
+       .read = vb2_fop_read,
+       .mmap = vb2_fop_mmap,
+       .poll = vb2_fop_poll,
+};
+
+/*
+ * The initial setup of this device instance. Note that the initial state of
+ * the driver should be complete. So the initial format, standard, timings
+ * and video input should all be initialized to some reasonable value.
+ */
+static int skeleton_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+       /* The initial timings are chosen to be 720p60. */
+       static const struct v4l2_dv_timings timings_def =
+               V4L2_DV_BT_CEA_1280X720P60;
+       struct skeleton *skel;
+       struct video_device *vdev;
+       struct v4l2_ctrl_handler *hdl;
+       struct vb2_queue *q;
+       int ret;
+
+       /* Enable PCI */
+       ret = pci_enable_device(pdev);
+       if (ret)
+               return ret;
+       ret = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+       if (ret) {
+               dev_err(&pdev->dev, "no suitable DMA available.\n");
+               goto disable_pci;
+       }
+
+       /* Allocate a new instance */
+       skel = devm_kzalloc(&pdev->dev, sizeof(struct skeleton), GFP_KERNEL);
+       if (!skel)
+               return -ENOMEM;
+
+       /* Allocate the interrupt */
+       ret = devm_request_irq(&pdev->dev, pdev->irq,
+                              skeleton_irq, 0, KBUILD_MODNAME, skel);
+       if (ret) {
+               dev_err(&pdev->dev, "request_irq failed\n");
+               goto disable_pci;
+       }
+       skel->pdev = pdev;
+
+       /* Fill in the initial format-related settings */
+       skel->timings = timings_def;
+       skel->std = V4L2_STD_625_50;
+       skeleton_fill_pix_format(skel, &skel->format);
+
+       /* Initialize the top-level structure */
+       ret = v4l2_device_register(&pdev->dev, &skel->v4l2_dev);
+       if (ret)
+               goto disable_pci;
+
+       mutex_init(&skel->lock);
+
+       /* Add the controls */
+       hdl = &skel->ctrl_handler;
+       v4l2_ctrl_handler_init(hdl, 4);
+       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
+                         V4L2_CID_BRIGHTNESS, 0, 255, 1, 127);
+       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
+                         V4L2_CID_CONTRAST, 0, 255, 1, 16);
+       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
+                         V4L2_CID_SATURATION, 0, 255, 1, 127);
+       v4l2_ctrl_new_std(hdl, &skel_ctrl_ops,
+                         V4L2_CID_HUE, -128, 127, 1, 0);
+       if (hdl->error) {
+               ret = hdl->error;
+               goto free_hdl;
+       }
+       skel->v4l2_dev.ctrl_handler = hdl;
+
+       /* Initialize the vb2 queue */
+       q = &skel->queue;
+       q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+       q->io_modes = VB2_MMAP | VB2_DMABUF | VB2_READ;
+       q->drv_priv = skel;
+       q->buf_struct_size = sizeof(struct skel_buffer);
+       q->ops = &skel_qops;
+       q->mem_ops = &vb2_dma_contig_memops;
+       q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+       /*
+        * Assume that this DMA engine needs to have at least two buffers
+        * available before it can be started. The start_streaming() op
+        * won't be called until at least this many buffers are queued up.
+        */
+       q->min_buffers_needed = 2;
+       /*
+        * The serialization lock for the streaming ioctls. This is the same
+        * as the main serialization lock, but if some of the non-streaming
+        * ioctls could take a long time to execute, then you might want to
+        * have a different lock here to prevent VIDIOC_DQBUF from being
+        * blocked while waiting for another action to finish. This is
+        * generally not needed for PCI devices, but USB devices usually do
+        * want a separate lock here.
+        */
+       q->lock = &skel->lock;
+       /*
+        * Since this driver can only do 32-bit DMA we must make sure that
+        * the vb2 core will allocate the buffers in 32-bit DMA memory.
+        */
+       q->gfp_flags = GFP_DMA32;
+       ret = vb2_queue_init(q);
+       if (ret)
+               goto free_hdl;
+
+       skel->alloc_ctx = vb2_dma_contig_init_ctx(&pdev->dev);
+       if (IS_ERR(skel->alloc_ctx)) {
+               dev_err(&pdev->dev, "Can't allocate buffer context");
+               ret = PTR_ERR(skel->alloc_ctx);
+               goto free_hdl;
+       }
+       INIT_LIST_HEAD(&skel->buf_list);
+       spin_lock_init(&skel->qlock);
+
+       /* Initialize the video_device structure */
+       vdev = &skel->vdev;
+       strlcpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
+       /*
+        * There is nothing to clean up, so release is set to an empty release
+        * function. The release callback must be non-NULL.
+        */
+       vdev->release = video_device_release_empty;
+       vdev->fops = &skel_fops,
+       vdev->ioctl_ops = &skel_ioctl_ops,
+       /*
+        * The main serialization lock. All ioctls are serialized by this
+        * lock. Exception: if q->lock is set, then the streaming ioctls
+        * are serialized by that separate lock.
+        */
+       vdev->lock = &skel->lock;
+       vdev->queue = q;
+       vdev->v4l2_dev = &skel->v4l2_dev;
+       /* Supported SDTV standards, if any */
+       vdev->tvnorms = SKEL_TVNORMS;
+       video_set_drvdata(vdev, skel);
+
+       ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
+       if (ret)
+               goto free_ctx;
+
+       dev_info(&pdev->dev, "V4L2 PCI Skeleton Driver loaded\n");
+       return 0;
+
+free_ctx:
+       vb2_dma_contig_cleanup_ctx(skel->alloc_ctx);
+free_hdl:
+       v4l2_ctrl_handler_free(&skel->ctrl_handler);
+       v4l2_device_unregister(&skel->v4l2_dev);
+disable_pci:
+       pci_disable_device(pdev);
+       return ret;
+}
+
+static void skeleton_remove(struct pci_dev *pdev)
+{
+       struct v4l2_device *v4l2_dev = pci_get_drvdata(pdev);
+       struct skeleton *skel = container_of(v4l2_dev, struct skeleton, v4l2_dev);
+
+       video_unregister_device(&skel->vdev);
+       v4l2_ctrl_handler_free(&skel->ctrl_handler);
+       vb2_dma_contig_cleanup_ctx(skel->alloc_ctx);
+       v4l2_device_unregister(&skel->v4l2_dev);
+       pci_disable_device(skel->pdev);
+}
+
+static struct pci_driver skeleton_driver = {
+       .name = KBUILD_MODNAME,
+       .probe = skeleton_probe,
+       .remove = skeleton_remove,
+       .id_table = skeleton_pci_tbl,
+};
+
+module_pci_driver(skeleton_driver);