[PATCH v8 1/2] [media] atmel-isc: add the Image Sensor Controller code

On 08/03/2016 10:08 AM, Songjun Wu wrote:

Add driver for the Image Sensor Controller. It manages
incoming data from a parallel based CMOS/CCD sensor.
It has an internal image processor, also integrates a
triple channel direct memory access controller master
interface.

Signed-off-by: Songjun Wu <redacted>
---

Changes in v8:
- Power on the sensor on the first open in function
  'isc_open'.
- Power off the sensor on the last release in function
  'isc_release'.
- Remove the switch of the pipeline.

Changes in v7:
- Add enum_framesizes and enum_frameintervals.
- Call s_stream(0) when stream start fail.
- Fill the device_caps field of struct video_device
  with V4L2_CAP_STREAMING and V4L2_CAP_VIDEO_CAPTURE.
- Initialize the dev of struct vb2_queue.
- Set field to FIELD_NONE if the pix field is not supported.
- Return the result directly when call g/s_parm of subdev.

Changes in v6: None
Changes in v5:
- Modify the macro definition and the related code.

Changes in v4:
- Modify the isc clock code since the dt is changed.

Changes in v3:
- Add pm runtime feature.
- Modify the isc clock code since the dt is changed.

Changes in v2:
- Add "depends on COMMON_CLK" and "VIDEO_V4L2_SUBDEV_API"
  in Kconfig file.
- Correct typos and coding style according to Laurent's remarks
- Delete the loop while in 'isc_clk_enable' function.
- Replace 'hsync_active', 'vsync_active' and 'pclk_sample'
  with 'pfe_cfg0' in struct isc_subdev_entity.
- Add the code to support VIDIOC_CREATE_BUFS in
  'isc_queue_setup' function.
- Invoke isc_config to configure register in
  'isc_start_streaming' function.
- Add the struct completion 'comp' to synchronize with
  the frame end interrupt in 'isc_stop_streaming' function.
- Check the return value of the clk_prepare_enable
  in 'isc_open' function.
- Set the default format in 'isc_open' function.
- Add an exit condition in the loop while in 'isc_config'.
- Delete the hardware setup operation in 'isc_set_format'.
- Refuse format modification during streaming
  in 'isc_s_fmt_vid_cap' function.
- Invoke v4l2_subdev_alloc_pad_config to allocate and
  initialize the pad config in 'isc_async_complete' function.
- Remove the '.owner  = THIS_MODULE,' in atmel_isc_driver.
- Replace the module_platform_driver_probe() with
  module_platform_driver().

 drivers/media/platform/Kconfig                |    1 +
 drivers/media/platform/Makefile               |    2 +
 drivers/media/platform/atmel/Kconfig          |    9 +
 drivers/media/platform/atmel/Makefile         |    1 +
 drivers/media/platform/atmel/atmel-isc-regs.h |  165 +++
 drivers/media/platform/atmel/atmel-isc.c      | 1503 +++++++++++++++++++++++++
 6 files changed, 1681 insertions(+)
 create mode 100644 drivers/media/platform/atmel/Kconfig
 create mode 100644 drivers/media/platform/atmel/Makefile
 create mode 100644 drivers/media/platform/atmel/atmel-isc-regs.h
 create mode 100644 drivers/media/platform/atmel/atmel-isc.c

<snip>

<snip>

+static int isc_set_default_fmt(struct isc_device *isc)
+{
+	u32 index = isc->num_user_formats - 1;

Why pick the last format? Strictly speaking it doesn't matter, but in practice
the most common formats tend to be at the beginning of the format list.

+	struct v4l2_format f = {
+		.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
+		.fmt.pix = {
+			.width		= VGA_WIDTH,
+			.height		= VGA_HEIGHT,
+			.field		= V4L2_FIELD_NONE,
+			.pixelformat	= isc->user_formats[index]->fourcc,
+		},
+	};
+
+	return isc_set_fmt(isc, &f);
+}
+
+static int isc_open(struct file *file)
+{
+	struct isc_device *isc = video_drvdata(file);
+	struct v4l2_subdev *sd = isc->current_subdev->sd;
+	int ret;
+
+	if (mutex_lock_interruptible(&isc->lock))
+		return -ERESTARTSYS;
+
+	ret = v4l2_fh_open(file);
+	if (ret < 0)
+		goto unlock;
+
+	if (!v4l2_fh_is_singular_file(file))
+		goto unlock;
+
+	ret = v4l2_subdev_call(sd, core, s_power, 1);
+	if (ret < 0 && ret != -ENOIOCTLCMD)
+		goto unlock;
+
+	ret = isc_set_default_fmt(isc);

This doesn't belong here, this needs to be done in isc_async_complete().

Having the code here means that every time you open the device, the format
changes back to the default. That's not what you want.

+	if (ret)
+		goto unlock;
+
+unlock:
+	mutex_unlock(&isc->lock);
+	return ret;
+}
+

<snip>

+static int isc_async_complete(struct v4l2_async_notifier *notifier)
+{
+	struct isc_device *isc = container_of(notifier->v4l2_dev,
+					      struct isc_device, v4l2_dev);
+	struct isc_subdev_entity *sd_entity;
+	struct video_device *vdev = &isc->video_dev;
+	struct vb2_queue *q = &isc->vb2_vidq;
+	int ret;
+
+	isc->current_subdev = container_of(notifier,
+					   struct isc_subdev_entity, notifier);
+	sd_entity = isc->current_subdev;
+
+	mutex_init(&isc->lock);
+	init_completion(&isc->comp);
+
+	/* Initialize videobuf2 queue */
+	q->type			= V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	q->io_modes		= VB2_MMAP | VB2_DMABUF | VB2_READ;
+	q->drv_priv		= isc;
+	q->buf_struct_size	= sizeof(struct isc_buffer);
+	q->ops			= &isc_vb2_ops;
+	q->mem_ops		= &vb2_dma_contig_memops;
+	q->timestamp_flags	= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	q->lock			= &isc->lock;
+	q->min_buffers_needed	= 1;
+	q->dev			= isc->dev;
+
+	ret = vb2_queue_init(q);
+	if (ret < 0) {
+		v4l2_err(&isc->v4l2_dev,
+			 "vb2_queue_init() failed: %d\n", ret);
+		return ret;
+	}
+
+	/* Init video dma queues */
+	INIT_LIST_HEAD(&isc->dma_queue);
+	spin_lock_init(&isc->dma_queue_lock);
+
+	/* Register video device */
+	strlcpy(vdev->name, ATMEL_ISC_NAME, sizeof(vdev->name));
+	vdev->release		= video_device_release_empty;
+	vdev->fops		= &isc_fops;
+	vdev->ioctl_ops		= &isc_ioctl_ops;
+	vdev->v4l2_dev		= &isc->v4l2_dev;
+	vdev->vfl_dir		= VFL_DIR_RX;
+	vdev->queue		= q;
+	vdev->lock		= &isc->lock;
+	vdev->ctrl_handler	= isc->current_subdev->sd->ctrl_handler;
+	vdev->device_caps	= V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE;
+	video_set_drvdata(vdev, isc);
+
+	ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
+	if (ret < 0) {
+		v4l2_err(&isc->v4l2_dev,
+			 "video_register_device failed: %d\n", ret);
+		return ret;
+	}

This should be done last. Once the device is registered apps can use it, so
everything should be configured.

+
+	sd_entity->config = v4l2_subdev_alloc_pad_config(sd_entity->sd);
+	if (sd_entity->config == NULL)
+		return -ENOMEM;
+
+	ret = isc_formats_init(isc);
+	if (ret < 0) {
+		v4l2_err(&isc->v4l2_dev,
+			 "Init format failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}

Regards,

	Hans