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authorLaurent Pinchart <laurent.pinchart@ideasonboard.com>2022-06-14 22:11:09 +0300
committerMauro Carvalho Chehab <mchehab@kernel.org>2022-07-17 13:23:10 +0300
commit5680fe45d66bbef32a902c04889a523fa4fc33ba (patch)
treedf50b09e239b51edc3ca8095bf6c2c554397e8ea /include/media
parentb2e44430b6348f68f56e78e932e6312f12128778 (diff)
downloadlinux-5680fe45d66bbef32a902c04889a523fa4fc33ba.tar.xz
media: mc-entity: Add a new helper function to get a remote pad
The media_entity_remote_pad_first() helper function returns the first remote pad it finds connected to a given pad. Beside being possibly non-deterministic (as it stops at the first enabled link), the fact that it returns the first match makes it unsuitable for drivers that need to guarantee that a single link is enabled, for instance when an entity can process data from one of multiple sources at a time. For those use cases, add a new helper function, media_entity_remote_pad_unique(), that operates on an entity and returns a remote pad, with a guarantee that only one link is enabled. To ease its use in drivers, also add an inline wrapper that locates source pads specifically. A wrapper that locates sink pads can easily be added when needed. 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>
Diffstat (limited to 'include/media')
-rw-r--r--include/media/media-entity.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 5e272a0a9895..c5618f7c1408 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -860,6 +860,52 @@ 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_entity_remote_pad_unique - Find a remote pad connected to an entity
+ * @entity: The entity
+ * @type: The type of pad to find (MEDIA_PAD_FL_SINK or MEDIA_PAD_FL_SOURCE)
+ *
+ * Search for and return a remote pad of @type connected to @entity through an
+ * enabled link. If multiple (or no) remote pads match these criteria, an error
+ * is returned.
+ *
+ * The uniqueness constraint makes this helper function suitable for entities
+ * that support a single active source or sink at a time.
+ *
+ * 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_entity_remote_pad_unique(const struct media_entity *entity,
+ unsigned int type);
+
+/**
+ * media_entity_remote_source_pad_unique - Find a remote source pad connected to
+ * an entity
+ * @entity: The entity
+ *
+ * Search for and return a remote source pad connected to @entity through an
+ * enabled link. If multiple (or no) remote pads match these criteria, an error
+ * is returned.
+ *
+ * The uniqueness constraint makes this helper function suitable for entities
+ * that support a single active source at a time.
+ *
+ * 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
+ */
+static inline struct media_pad *
+media_entity_remote_source_pad_unique(const struct media_entity *entity)
+{
+ return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE);
+}
+
+/**
* media_entity_is_streaming - Test if an entity is part of a streaming pipeline
* @entity: The entity
*