On 04/05/2020 11:25, Laurent Pinchart wrote:
> From: Naushir Patuck <naush@xxxxxxxxxxxxxxx>
>
> Add V4L2_META_FMT_SENSOR_DATA format 4CC.
>
> This new format will be used by the BCM2835 Unicam device to return
> out camera sensor embedded data.
out -> our (I think)
>
> Signed-off-by: Naushir Patuck <naush@xxxxxxxxxxxxxxx>
> ---
> Documentation/media/uapi/v4l/meta-formats.rst | 1 +
> .../uapi/v4l/pixfmt-meta-sensor-data.rst | 32 +++++++++++++++++++
> drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
> include/uapi/linux/videodev2.h | 1 +
> 4 files changed, 35 insertions(+)
> create mode 100644 Documentation/media/uapi/v4l/pixfmt-meta-sensor-data.rst
>
> diff --git a/Documentation/media/uapi/v4l/meta-formats.rst b/Documentation/media/uapi/v4l/meta-formats.rst
> index 74c8659ee9d6..5474086ef6f0 100644
> --- a/Documentation/media/uapi/v4l/meta-formats.rst
> +++ b/Documentation/media/uapi/v4l/meta-formats.rst
> @@ -21,6 +21,7 @@ These formats are used for the :ref:`metadata` interface only.
>
> pixfmt-meta-d4xx
> pixfmt-meta-intel-ipu3
> + pixfmt-meta-sensor-data
> pixfmt-meta-uvc
> pixfmt-meta-vsp1-hgo
> pixfmt-meta-vsp1-hgt
> diff --git a/Documentation/media/uapi/v4l/pixfmt-meta-sensor-data.rst b/Documentation/media/uapi/v4l/pixfmt-meta-sensor-data.rst
> new file mode 100644
> index 000000000000..4a67e204d08a
> --- /dev/null
> +++ b/Documentation/media/uapi/v4l/pixfmt-meta-sensor-data.rst
> @@ -0,0 +1,32 @@
> +.. Permission is granted to copy, distribute and/or modify this
> +.. document under the terms of the GNU Free Documentation License,
> +.. Version 1.1 or any later version published by the Free Software
> +.. Foundation, with no Invariant Sections, no Front-Cover Texts
> +.. and no Back-Cover Texts. A copy of the license is included at
> +.. Documentation/media/uapi/fdl-appendix.rst.
> +..
> +.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
> +
> +.. _v4l2-meta-fmt-sensor-data:
> +
> +***********************************
> +V4L2_META_FMT_SENSOR_DATA ('SENS')
> +***********************************
> +
> +Sensor Ancillary Metadata
> +
> +Description
> +===========
> +
> +This format describes ancillary data generated by a camera sensor and
> +transmitted over a stream on the camera bus. Sensor vendors generally have their
'generally' can be dropped.
> +own custom format for this ancillary data. Some vendors follow a generic
> +CSI-2/SMIA embedded data format as described in the `CSI-2 specification.
> +<https://mipi.org/specifications/csi-2>`_
So what does this format represent? Sensor specific custom data where you need
sensor-specific NDA knowledge in userspace to parse it? Or SMIA formatted sensor
data?
A 4cc should map to a specific data format. I understand that this is not always
known, but at least the SMIA data format would need its own 4cc. I assume that the
sensor driver will at least know that it produces SMIA data, right?
"SENSOR_DATA" is also much too generic IMHO.
> +
> +The size of the embedded buffer is defined as a single line with a pixel width
> +width specified in bytes. This is obtained by a call to the
"pixel width width"? Typo?
> +:c:type:`VIDIOC_SUBDEV_G_FMT` ioctl on the sensor subdevice where the ``pad``
> +field in :c:type:`v4l2_subdev_format` is set to 1. Note that this size is fixed
Should this description be explicit about the pad number?
Regards,
Hans
> +and cannot be modified with a call to :c:type:`VIDIOC_SUBDEV_S_FMT`.
> +
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index b2ef8e60ea7d..faf5a0f5eb6b 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1346,6 +1346,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_META_FMT_UVC: descr = "UVC Payload Header Metadata"; break;
> case V4L2_META_FMT_D4XX: descr = "Intel D4xx UVC Metadata"; break;
> case V4L2_META_FMT_VIVID: descr = "Vivid Metadata"; break;
> + case V4L2_META_FMT_SENSOR_DATA: descr = "Sensor Ancillary Metadata"; break;
>
> default:
> /* Compressed formats */
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 9817b7e2c968..a96146223843 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -766,6 +766,7 @@ struct v4l2_pix_format {
> #define V4L2_META_FMT_UVC v4l2_fourcc('U', 'V', 'C', 'H') /* UVC Payload Header metadata */
> #define V4L2_META_FMT_D4XX v4l2_fourcc('D', '4', 'X', 'X') /* D4XX Payload Header metadata */
> #define V4L2_META_FMT_VIVID v4l2_fourcc('V', 'I', 'V', 'D') /* Vivid Metadata */
> +#define V4L2_META_FMT_SENSOR_DATA v4l2_fourcc('S', 'E', 'N', 'S') /* Sensor Ancillary metadata */
>
> /* priv field value to indicates that subsequent fields are valid. */
> #define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe
>
