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media: mc-entity: Add a new helper function to get a remote pad for a pad

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The newly added media_entity_remote_source_pad_unique() 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_unique()
function to handle this. It operates as
media_entity_remote_source_pad_unique(), but on a given pad instead of
on the entity.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Laurent Pinchart 2022-06-14 20:11:10 +01:00 committed by Mauro Carvalho Chehab
parent 5680fe45d6
commit 03b282861c
3 changed files with 52 additions and 2 deletions
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5
Documentation/driver-api/media/mc-core.rst
View File

@ -186,8 +186,9 @@ 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_pad_remote_pad_first()` and
:c:func:`media_entity_remote_source_pad_unique()`).
(:c:func:`media_entity_find_link()`, :c:func:`media_pad_remote_pad_first()`n
:c:func:`media_entity_remote_source_pad_unique()` and
:c:func:`media_pad_remote_pad_unique()`).
Use count and power handling
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

31
drivers/media/mc/mc-entity.c
View File

@ -960,6 +960,37 @@ 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_unique(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_unique);
static void media_interface_init(struct media_device *mdev,
struct media_interface *intf,
u32 gobj_type,

18
include/media/media-entity.h
View File

@ -859,6 +859,24 @@ struct media_link *media_entity_find_link(struct media_pad *source,
*/
struct media_pad *media_pad_remote_pad_first(const struct media_pad *pad);
/**
* media_pad_remote_pad_unique - 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_unique(const struct media_pad *pad);
/**
* media_entity_remote_pad_unique - Find a remote pad connected to an entity
* @entity: The entity