OSCL-LXR linux-6.0.1/​samples/​v4l/​v4l2-pci-skeleton.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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.
  */
 
 #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
  * @qlock: spinlock controlling access to buf_list and sequence
  * @buf_list: list of buffers queued for DMA
  * @field: the field (TOP/BOTTOM/other) of the current buffer
  * @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;
 
     spinlock_t qlock;
     struct list_head buf_list;
     unsigned field;
     unsigned sequence;
 };
 
 struct skel_buffer {
     struct vb2_v4l2_buffer vb;
     struct list_head list;
 };
 
 static inline struct skel_buffer *to_skel_buffer(struct vb2_v4l2_buffer *vbuf)
 {
     return container_of(vbuf, 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);
         new_buf->vb.vb2_buf.timestamp = ktime_get_ns();
         new_buf->vb.sequence = skel->sequence++;
         new_buf->vb.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, 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[], struct device *alloc_devs[])
 {
     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;
 
     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 vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
     struct skeleton *skel = vb2_get_drv_priv(vb->vb2_queue);
     struct skel_buffer *buf = to_skel_buffer(vbuf);
     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.vb2_buf, 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 const 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));
     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 = dma_set_mask(&pdev->dev, 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) {
         ret = -ENOMEM;
         goto disable_pci;
     }
 
     /* 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->dev = &pdev->dev;
     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;
 
     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,
     vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
                 V4L2_CAP_STREAMING;
     /*
      * 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_VIDEO, -1);
     if (ret)
         goto free_hdl;
 
     dev_info(&pdev->dev, "V4L2 PCI Skeleton Driver loaded\n");
     return 0;
 
 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);
     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);

This page was automatically generated by the 2.1.0 LXR engine. The LXR team