Re: [PATCH v3 06/22] media: Media Controller enable/disable source handler API

Sakari Ailus
2016-03-10T07:35:20Z

Hi Shuah,

On Thu, Feb 11, 2016 at 04:41:22PM -0700, Shuah Khan wrote:
> 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 used to run these handlers. The enable_source handler
> finds source entity for the passed in entity and checks if it is
> available. When link is found, it activates it. Disable source
> handler deactivates the link.
>
> Bridge driver is expected to implement and set these handlers.
>
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
> include/media/media-device.h | 30 ++++++++++++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 075a482..1a04644 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -302,6 +302,11 @@ struct media_entity_notify {
> * @entity_notify: List of registered entity_notify callbacks
> * @lock: Entities list lock
> * @graph_mutex: Entities graph operation lock
> + *
> + * @source_priv: Driver Private data for enable/disable source handlers
> + * @enable_source: Enable Source Handler function pointer
> + * @disable_source: Disable Source Handler function pointer
> + *
> * @link_notify: Link state change notification callback
> *
> * This structure represents an abstract high-level media device. It allows easy
> @@ -313,6 +318,26 @@ struct media_entity_notify {
> *
> * @model is a descriptive model name exported through sysfs. It doesn't have to
> * be unique.
> + *
> + * @enable_source is a handler to find source entity for the
> + * sink entity and activate the link between them if source
> + * entity is free. Drivers should call this handler before
> + * accessing the source.
> + *
> + * @disable_source is a handler to find source entity for the
> + * sink entity and deactivate the link between them. Drivers
> + * should call this handler to release the source.
> + *

Is there a particular reason you're not simply (de)activating the link, but
instead add a new callback?

> + * Note: 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
> + * the link between them from enable_source and deactivate
> + * from disable_source.
> */
> struct media_device {
> /* dev->driver_data points to this struct. */
> @@ -344,6 +369,11 @@ struct media_device {
> /* Serializes graph operations. */
> struct mutex graph_mutex;
>
> + void *source_priv;
> + int (*enable_source)(struct media_entity *entity,
> + struct media_pipeline *pipe);
> + void (*disable_source)(struct media_entity *entity);
> +
> int (*link_notify)(struct media_link *link, u32 flags,
> unsigned int notification);
> };

--
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk