From b76a2a8cb6f6d9da711305d805156b40c698e94f Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 29 Feb 2016 08:45:44 -0300 Subject: [media] media: Add obj_type field to struct media_entity Code that processes media entities can require knowledge of the structure type that embeds a particular media entity instance in order to cast the entity to the proper object type. This needs is shown by the presence of the is_media_entity_v4l2_io and is_media_entity_v4l2_subdev functions. The implementation of those two functions relies on the entity function field, which is both a wrong and an inefficient design, without even mentioning the maintenance issue involved in updating the functions every time a new entity function is added. Fix this by adding add an obj_type field to the media entity structure to carry the information. Signed-off-by: Laurent Pinchart Acked-by: Hans Verkuil Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- include/media/media-entity.h | 76 +++++++++++++++++++++++--------------------- 1 file changed, 39 insertions(+), 37 deletions(-) (limited to 'include/media/media-entity.h') diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 6dc9e4e8cbd4..1986340a8cf2 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -187,11 +187,39 @@ struct media_entity_operations { int (*link_validate)(struct media_link *link); }; +/** + * enum media_entity_type - Media entity type + * + * @MEDIA_ENTITY_TYPE_BASE: + * The entity isn't embedded in another subsystem structure. + * @MEDIA_ENTITY_TYPE_VIDEO_DEVICE: + * The entity is embedded in a struct video_device instance. + * @MEDIA_ENTITY_TYPE_V4L2_SUBDEV: + * The entity is embedded in a struct v4l2_subdev instance. + * + * Media entity objects are often not instantiated directly, but the media + * entity structure is inherited by (through embedding) other subsystem-specific + * structures. The media entity type identifies the type of the subclass + * structure that implements a media entity instance. + * + * This allows runtime type identification of media entities and safe casting to + * the correct object type. For instance, a media entity structure instance + * embedded in a v4l2_subdev structure instance will have the type + * MEDIA_ENTITY_TYPE_V4L2_SUBDEV and can safely be cast to a v4l2_subdev + * structure using the container_of() macro. + */ +enum media_entity_type { + MEDIA_ENTITY_TYPE_BASE, + MEDIA_ENTITY_TYPE_VIDEO_DEVICE, + MEDIA_ENTITY_TYPE_V4L2_SUBDEV, +}; + /** * struct media_entity - A media entity graph object. * * @graph_obj: Embedded structure containing the media object common data. * @name: Entity name. + * @obj_type: Type of the object that implements the media_entity. * @function: Entity main function, as defined in uapi/media.h * (MEDIA_ENT_F_*) * @flags: Entity flags, as defined in uapi/media.h (MEDIA_ENT_FL_*) @@ -220,6 +248,7 @@ struct media_entity_operations { struct media_entity { struct media_gobj graph_obj; /* must be first field in struct */ const char *name; + enum media_entity_type obj_type; u32 function; unsigned long flags; @@ -329,56 +358,29 @@ static inline u32 media_gobj_gen_id(enum media_gobj_type type, u64 local_id) } /** - * is_media_entity_v4l2_io() - identify if the entity main function - * is a V4L2 I/O - * + * is_media_entity_v4l2_io() - Check if the entity is a video_device * @entity: pointer to entity * - * Return: true if the entity main function is one of the V4L2 I/O types - * (video, VBI or SDR radio); false otherwise. + * Return: true if the entity is an instance of a video_device object and can + * safely be cast to a struct video_device using the container_of() macro, or + * false otherwise. */ static inline bool is_media_entity_v4l2_io(struct media_entity *entity) { - if (!entity) - return false; - - switch (entity->function) { - case MEDIA_ENT_F_IO_V4L: - case MEDIA_ENT_F_IO_VBI: - case MEDIA_ENT_F_IO_SWRADIO: - return true; - default: - return false; - } + return entity && entity->obj_type == MEDIA_ENTITY_TYPE_VIDEO_DEVICE; } /** - * is_media_entity_v4l2_subdev - return true if the entity main function is - * associated with the V4L2 API subdev usage - * + * is_media_entity_v4l2_subdev() - Check if the entity is a v4l2_subdev * @entity: pointer to entity * - * This is an ancillary function used by subdev-based V4L2 drivers. - * It checks if the entity function is one of functions used by a V4L2 subdev, - * e. g. camera-relatef functions, analog TV decoder, TV tuner, V4L2 DSPs. + * Return: true if the entity is an instance of a v4l2_subdev object and can + * safely be cast to a struct v4l2_subdev using the container_of() macro, or + * false otherwise. */ static inline bool is_media_entity_v4l2_subdev(struct media_entity *entity) { - if (!entity) - return false; - - switch (entity->function) { - case MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN: - case MEDIA_ENT_F_CAM_SENSOR: - case MEDIA_ENT_F_FLASH: - case MEDIA_ENT_F_LENS: - case MEDIA_ENT_F_ATV_DECODER: - case MEDIA_ENT_F_TUNER: - return true; - - default: - return false; - } + return entity && entity->obj_type == MEDIA_ENTITY_TYPE_V4L2_SUBDEV; } /** -- cgit v1.2.3