[media] media: Add link_validate() op to check links to the sink pad

The purpose of the link_validate() op is to allow an entity driver to ensure
that the properties of the pads at the both ends of the link are suitable
for starting the pipeline. link_validate is called on sink pads on active
links which belong to the active part of the graph.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 29e7bba78ffe..0c16f518ee09 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -46,6 +46,7 @@ struct media_entity_operations {
         int (*link_setup)(struct media_entity *entity,
                           const struct media_pad *local,
                           const struct media_pad *remote, u32 flags);
+        int (*link_validate)(struct media_link *link);
 };
 
 struct media_entity {
@@ -140,8 +141,8 @@ void media_entity_graph_walk_start(struct media_entity_graph *graph,
                 struct media_entity *entity);
 struct media_entity *
 media_entity_graph_walk_next(struct media_entity_graph *graph);
-void media_entity_pipeline_start(struct media_entity *entity,
-                struct media_pipeline *pipe);
+__must_check int media_entity_pipeline_start(struct media_entity *entity,
+                                             struct media_pipeline *pipe);
 void media_entity_pipeline_stop(struct media_entity *entity);
 
 #define media_entity_call(entity, operation, args...)                   \