media: vimc: stream: format comments as kernel-doc

Format the current existing comments as kernel-doc comments, to be
reused at kernel documention. Add opening marks (/**) and return values.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/vimc/vimc-streamer.c

@@ -20,6 +20,8 @@
  *
  * Helper function that returns the media entity containing the source pad
  * linked with the first sink pad from the given media entity pad list.
+ *
+ * Return: The source pad or NULL, if it wasn't found.
  */
 static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
 {
@@ -35,7 +37,7 @@ static struct media_entity *vimc_get_source_entity(struct media_entity *ent)
 	return NULL;
 }
 
-/*
+/**
  * vimc_streamer_pipeline_terminate - Disable stream in all ved in stream
  *
  * @stream: the pointer to the stream structure with the pipeline to be
@@ -63,15 +65,18 @@ static void vimc_streamer_pipeline_terminate(struct vimc_stream *stream)
 	}
 }
 
-/*
- * vimc_streamer_pipeline_init - initializes the stream structure
+/**
+ * vimc_streamer_pipeline_init - Initializes the stream structure
  *
  * @stream: the pointer to the stream structure to be initialized
  * @ved:    the pointer to the vimc entity initializing the stream
  *
  * Initializes the stream structure. Walks through the entity graph to
  * construct the pipeline used later on the streamer thread.
- * Calls s_stream to enable stream in all entities of the pipeline.
+ * Calls vimc_streamer_s_stream() to enable stream in all entities of
+ * the pipeline.
+ *
+ * Return: 0 if success, error code otherwise.
  */
 static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 				       struct vimc_ent_device *ved)
@@ -122,13 +127,17 @@ static int vimc_streamer_pipeline_init(struct vimc_stream *stream,
 	return -EINVAL;
 }
 
-/*
- * vimc_streamer_thread - process frames through the pipeline
+/**
+ * vimc_streamer_thread - Process frames through the pipeline
  *
  * @data:	vimc_stream struct of the current stream
  *
  * From the source to the sink, gets a frame from each subdevice and send to
  * the next one of the pipeline at a fixed framerate.
+ *
+ * Return:
+ * Always zero (created as ``int`` instead of ``void`` to comply with
+ * kthread API).
  */
 static int vimc_streamer_thread(void *data)
 {
@@ -157,19 +166,20 @@ static int vimc_streamer_thread(void *data)
 	return 0;
 }
 
-/*
- * vimc_streamer_s_stream - start/stop the streaming on the media pipeline
+/**
+ * vimc_streamer_s_stream - Start/stop the streaming on the media pipeline
  *
  * @stream:	the pointer to the stream structure of the current stream
  * @ved:	pointer to the vimc entity of the entity of the stream
  * @enable:	flag to determine if stream should start/stop
  *
- * When starting, check if there is no stream->kthread allocated. This should
- * indicate that a stream is already running. Then, it initializes
- * the pipeline, creates and runs a kthread to consume buffers through the
- * pipeline.
- * When stopping, analogously check if there is a stream running, stop
- * the thread and terminates the pipeline.
+ * When starting, check if there is no ``stream->kthread`` allocated. This
+ * should indicate that a stream is already running. Then, it initializes the
+ * pipeline, creates and runs a kthread to consume buffers through the pipeline.
+ * When stopping, analogously check if there is a stream running, stop the
+ * thread and terminates the pipeline.
+ *
+ * Return: 0 if success, error code otherwise.
  */
 int vimc_streamer_s_stream(struct vimc_stream *stream,
 			   struct vimc_ent_device *ved,