media: vimc: stream: add docs to struct vimc_stream

Add missing documentation for struct vimc_stream
Signed-off-by: Helen Koike <helen.koike@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.h

@@ -15,6 +15,21 @@
 
 #define VIMC_STREAMER_PIPELINE_MAX_SIZE 16
 
+/**
+ * struct vimc_stream - struct that represents a stream in the pipeline
+ *
+ * @pipe:		the media pipeline object associated with this stream
+ * @ved_pipeline:	array containing all the entities participating in the
+ * stream. The order is from a video device (usually a capture device) where
+ * stream_on was called, to the entity generating the first base image to be
+ * processed in the pipeline.
+ * @pipe_size:		size of @ved_pipeline
+ * @kthread:		thread that generates the frames of the stream.
+ *
+ * When the user call stream_on in a video device, struct vimc_stream is
+ * used to keep track of all entities and subdevices that generates and
+ * process frames for the stream.
+ */
 struct vimc_stream {
 	struct media_pipeline pipe;
 	struct vimc_ent_device *ved_pipeline[VIMC_STREAMER_PIPELINE_MAX_SIZE];