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authorMauro Carvalho Chehab <mchehab@osg.samsung.com>2015-12-11 09:44:40 (GMT)
committerMauro Carvalho Chehab <mchehab@osg.samsung.com>2016-01-11 14:19:03 (GMT)
commitab22e77cd3d3073c8cac51b59713ef635678dfbe (patch)
treedfe14b163cd094531b260cab7e7d69d035b751da /Documentation/media-framework.txt
parentb83e250833e6c40a9e92935ea6fc125b64792357 (diff)
downloadlinux-ab22e77cd3d3073c8cac51b59713ef635678dfbe.tar.xz
[media] media framework: rename pads init function to media_entity_pads_init()
With the MC next gen rework, what's left for media_entity_init() is to just initialize the PADs. However, certain devices, like a FLASH led/light doesn't have any input or output PAD. So, there's no reason why calling media_entity_init() would be mandatory. Also, despite its name, what this function actually does is to initialize the PADs data. So, rename it to media_entity_pads_init() in order to reflect that. The media entity actual init happens during entity register, at media_device_register_entity(). We should move init of num_links and num_backlinks to it. Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'Documentation/media-framework.txt')
-rw-r--r--Documentation/media-framework.txt18
1 files changed, 11 insertions, 7 deletions
diff --git a/Documentation/media-framework.txt b/Documentation/media-framework.txt
index b424de6..7fbfe4b 100644
--- a/Documentation/media-framework.txt
+++ b/Documentation/media-framework.txt
@@ -101,14 +101,18 @@ include/media/media-entity.h. The structure is usually embedded into a
higher-level structure, such as a v4l2_subdev or video_device instance,
although drivers can allocate entities directly.
-Drivers initialize entities by calling
+Drivers initialize entity pads by calling
- media_entity_init(struct media_entity *entity, u16 num_pads,
+ media_entity_pads_init(struct media_entity *entity, u16 num_pads,
struct media_pad *pads);
-The media_entity name, type, flags, revision and group_id fields can be
-initialized before or after calling media_entity_init. Entities embedded in
-higher-level standard structures can have some of those fields set by the
+If no pads are needed, drivers could directly fill entity->num_pads
+with 0 and entity->pads with NULL or to call the above function that
+will do the same.
+
+The media_entity name, type, flags, revision and group_id fields should be
+initialized before calling media_device_register_entity(). Entities embedded
+in higher-level standard structures can have some of those fields set by the
higher-level framework.
As the number of pads is known in advance, the pads array is not allocated
@@ -116,10 +120,10 @@ dynamically but is managed by the entity driver. Most drivers will embed the
pads array in a driver-specific structure, avoiding dynamic allocation.
Drivers must set the direction of every pad in the pads array before calling
-media_entity_init. The function will initialize the other pads fields.
+media_entity_pads_init. The function will initialize the other pads fields.
Unlike the number of pads, the total number of links isn't always known in
-advance by the entity driver. As an initial estimate, media_entity_init
+advance by the entity driver. As an initial estimate, media_entity_pads_init
pre-allocates a number of links equal to the number of pads. The links array
will be reallocated if it grows beyond the initial estimate.