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
