[alsa-devel] [PATCH 04/31] media: Media Controller enable/disable source handler API

[Mauro Carvalho Chehab]

Em Wed,  6 Jan 2016 13:26:53 -0700
Shuah Khan <shuahkh at osg.samsung.com> escreveu:

> Add new fields to struct media_device to add enable_source, and
> disable_source handlers, and source_priv to stash driver private
> data that is need to run these handlers. The enable_source handler
> finds source entity for the passed in entity and check if it is
> available, and activate the link using __media_entity_setup_link()
> interface. Bridge driver is expected to implement and set these
> handlers and private data when media_device is registered or when
> bridge driver finds the media_device during probe. This is to enable
> the use-case to find tuner entity connected to the decoder entity and
> check if it is available, and activate it and start pipeline between
> the source and the entity. The disable_source handler deactivates the
> link and stops the pipeline. This handler can be invoked from the
> media core (v4l-core, dvb-core) as well as other drivers such as ALSA
> that control the media device.
> 
> Signed-off-by: Shuah Khan <shuahkh at osg.samsung.com>
> ---
>  include/media/media-device.h | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 6520d1c..04b6c2e 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -333,6 +333,25 @@ struct media_device {
>  	/* Serializes graph operations. */
>  	struct mutex graph_mutex;
>  
> +	/* Handlers to find source entity for the sink entity and
> +	 * check if it is available, and activate the link using
> +	 * media_entity_setup_link() interface and start pipeline
> +	 * from the source to the entity.
> +	 * Bridge driver is expected to implement and set the
> +	 * handler when media_device is registered or when
> +	 * bridge driver finds the media_device during probe.
> +	 * Bridge driver sets source_priv with information
> +	 * necessary to run enable/disable source handlers.
> +	 *
> +	 * Use-case: find tuner entity connected to the decoder
> +	 * entity and check if it is available, and activate the
> +	 * using media_entity_setup_link() if it is available.
> +	*/
> +	void *source_priv;
> +	int (*enable_source)(struct media_entity *entity,
> +			     struct media_pipeline *pipe);
> +	void (*disable_source)(struct media_entity *entity);

Please document the new fields at the right place (Kernel-doc
comment declared before the struct).

Is this used by the media core? If so, please but the implementation
here, to make it clearer why we need those things.

> +
>  	int (*link_notify)(struct media_link *link, u32 flags,
>  			   unsigned int notification);
>  };