+ Sakari and Hans
On Wed, Jun 15, 2022 at 04:11:10AM +0900, Paul Elder wrote:
> From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> The newly added media_entity_remote_source_pad() helper function handles
> use cases where the entity has a link enabled uniqueness constraint
> covering all pads. There are use cases where the constraint covers a
> specific pad only. Add a new media_pad_remote_pad() function to handle
> this. It operates as media_entity_remote_source_pad(), but on a given
> pad instead of on the entity.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> Documentation/driver-api/media/mc-core.rst | 4 +--
> drivers/media/mc/mc-entity.c | 31 ++++++++++++++++++++++
> include/media/media-entity.h | 18 +++++++++++++
> 3 files changed, 51 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst
> index a2d1e32e3abb..83c3bdbf67be 100644
> --- a/Documentation/driver-api/media/mc-core.rst
> +++ b/Documentation/driver-api/media/mc-core.rst
> @@ -186,8 +186,8 @@ is required and the graph structure can be freed normally.
>
> Helper functions can be used to find a link between two given pads, or a pad
> connected to another pad through an enabled link
> -(:c:func:`media_entity_find_link()`, :c:func:`media_entity_remote_pad()` and
> -:c:func:`media_entity_remote_source_pad()`).
> +(:c:func:`media_entity_find_link()`, :c:func:`media_entity_remote_pad()`,
> +:c:func:`media_entity_remote_source_pad()` and :c:func:`media_pad_remote_pad()`).
>
> Use count and power handling
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c
> index 1febf5a86be6..6429b0510bfb 100644
> --- a/drivers/media/mc/mc-entity.c
> +++ b/drivers/media/mc/mc-entity.c
> @@ -958,6 +958,37 @@ media_entity_remote_pad_unique(const struct media_entity *entity,
> }
> EXPORT_SYMBOL_GPL(media_entity_remote_pad_unique);
>
> +struct media_pad *media_pad_remote_pad(const struct media_pad *pad)
> +{
> + struct media_pad *found_pad = NULL;
> + struct media_link *link;
> +
> + list_for_each_entry(link, &pad->entity->links, list) {
> + struct media_pad *remote_pad;
> +
> + if (!(link->flags & MEDIA_LNK_FL_ENABLED))
> + continue;
> +
> + if (link->sink == pad)
> + remote_pad = link->source;
> + else if (link->source == pad)
> + remote_pad = link->sink;
> + else
> + continue;
> +
> + if (found_pad)
> + return ERR_PTR(-ENOTUNIQ);
> +
> + found_pad = remote_pad;
> + }
> +
> + if (!found_pad)
> + return ERR_PTR(-ENOLINK);
> +
> + return found_pad;
> +}
> +EXPORT_SYMBOL_GPL(media_pad_remote_pad);
> +
> static void media_interface_init(struct media_device *mdev,
> struct media_interface *intf,
> u32 gobj_type,
> diff --git a/include/media/media-entity.h b/include/media/media-entity.h
> index 33d5f52719a0..bfe6a7b10a68 100644
> --- a/include/media/media-entity.h
> +++ b/include/media/media-entity.h
> @@ -904,6 +904,24 @@ media_entity_remote_source_pad(const struct media_entity *entity)
> return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE);
> }
>
> +/**
> + * media_pad_remote_pad - Find a remote pad connected to a pad
> + * @pad: The pad
> + *
> + * Search for and return a remote pad connected to @pad through an enabled
> + * link. If multiple (or no) remote pads are found, an error is returned.
> + *
> + * The uniqueness constraint makes this helper function suitable for entities
> + * that support a single active source at a time on a given pad.
> + *
> + * Return: A pointer to the remote pad, or one of the following error pointers
> + * if an error occurs:
> + *
> + * * -ENOTUNIQ - Multiple links are enabled
> + * * -ENOLINK - No connected pad found
> + */
> +struct media_pad *media_pad_remote_pad(const struct media_pad *pad);
> +
> /**
> * media_entity_is_streaming - Test if an entity is part of a streaming pipeline
> * @entity: The entity
> --
> 2.30.2
>
--
Regards,
Laurent Pinchart
