Re: [RFC PATCH 3/3] videodev2.h: add entity_id to struct v4l2_capability

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

Thank you for the patch.

On Friday 01 May 2015 13:33:50 Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> Export the entity ID (if any) of the video device.

I would postpone this until we finish the DVB+MC discussion and properly 
define the relationship between device nodes and MC, as it could have 
implications on the V4L2 side as well.

> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  Documentation/DocBook/media/v4l/vidioc-querycap.xml | 16 +++++++++++++++-
>  drivers/media/v4l2-core/v4l2-ioctl.c                |  7 +++++++
>  include/uapi/linux/videodev2.h                      |  5 ++++-
>  3 files changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index
> c1ed844..4a7737c 100644
> --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> @@ -154,7 +154,14 @@ printf ("Version: %u.%u.%u\n",
>  	  </row>
>  	  <row>
>  	    <entry>__u32</entry>
> -	    <entry><structfield>reserved</structfield>[3]</entry>
> +	    <entry><structfield>entity_id</structfield></entry>
> +	    <entry>The media controller entity ID of the device. This is only
> valid if
> +	    the <constant>V4L2_CAP_ENTITY</constant> capability is set.
> +	    </entry>
> +	  </row>
> +	  <row>
> +	    <entry>__u32</entry>
> +	    <entry><structfield>reserved</structfield>[2]</entry>
>  	    <entry>Reserved for future extensions. Drivers must set
>  this array to zero.</entry>
>  	  </row>
> @@ -308,6 +315,13 @@ modulator programming see
>  fields.</entry>
>  	  </row>
>  	  <row>
> +	    <entry><constant>V4L2_CAP_ENTITY</constant></entry>
> +	    <entry>0x00400000</entry>
> +	    <entry>The device is a media controller entity and
> +	    the <structfield>entity_id</structfield> field of &v4l2-capability;
> +	    is valid.</entry>
> +	  </row>
> +	  <row>
>  	    <entry><constant>V4L2_CAP_READWRITE</constant></entry>
>  	    <entry>0x01000000</entry>
>  	    <entry>The device supports the <link
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c
> b/drivers/media/v4l2-core/v4l2-ioctl.c index 1476602..5179611 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1011,6 +1011,7 @@ static void v4l_sanitize_format(struct v4l2_format
> *fmt) static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
>  				struct file *file, void *fh, void *arg)
>  {
> +	struct video_device *vfd = video_devdata(file);
>  	struct v4l2_capability *cap = (struct v4l2_capability *)arg;
>  	int ret;
> 
> @@ -1019,6 +1020,12 @@ static int v4l_querycap(const struct v4l2_ioctl_ops
> *ops, ret = ops->vidioc_querycap(file, fh, cap);
> 
>  	cap->capabilities |= V4L2_CAP_EXT_PIX_FORMAT;
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> +	if (vfd->entity.parent) {
> +		cap->capabilities |= V4L2_CAP_ENTITY;
> +		cap->entity_id = vfd->entity.id;
> +	}
> +#endif
>  	/*
>  	 * Drivers MUST fill in device_caps, so check for this and
>  	 * warn if it was forgotten.
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index fa376f7..af7a667 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -307,6 +307,7 @@ struct v4l2_fract {
>    * @version:	   KERNEL_VERSION
>    * @capabilities: capabilities of the physical device as a whole
>    * @device_caps:  capabilities accessed via this particular device (node)
> +  * @entity_id:    the media controller entity ID
>    * @reserved:	   reserved fields for future extensions
>    */
>  struct v4l2_capability {
> @@ -316,7 +317,8 @@ struct v4l2_capability {
>  	__u32   version;
>  	__u32	capabilities;
>  	__u32	device_caps;
> -	__u32	reserved[3];
> +	__u32	entity_id;
> +	__u32	reserved[2];
>  };
> 
>  /* Values for 'capabilities' field */
> @@ -348,6 +350,7 @@ struct v4l2_capability {
> 
>  #define V4L2_CAP_SDR_CAPTURE		0x00100000  /* Is a SDR capture device */
>  #define V4L2_CAP_EXT_PIX_FORMAT		0x00200000  /* Supports the extended 
pixel
> format */ +#define V4L2_CAP_ENTITY                 0x00400000  /* This is a
> Media Controller entity */
> 
>  #define V4L2_CAP_READWRITE              0x01000000  /* read/write
> systemcalls */ #define V4L2_CAP_ASYNCIO                0x02000000  /* async
> I/O */

-- 
Regards,

Laurent Pinchart