[PATCH 09/10] [media] uvcvideo: register entity subdev on init

From: Javier Martinez Canillas
Date: Fri Dec 11 2015 - 12:17:36 EST


The uvc_mc_register_entities() function iterated over the entities three
times to initialize the entities, register the subdev for the ones whose
type was UVC_TT_STREAMING and to create the entities links.

But this can be simplied by merging the init and registration logic in a
single loop.

Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>

---

This patch addresses an issue Laurent pointed in patch [0]:

- Move the v4l2_device_register_subdev() call to uvc_mc_init_entity().

[0]: https://lkml.org/lkml/2015/12/5/253

drivers/media/usb/uvc/uvc_entity.c | 33 +++++++++------------------------
1 file changed, 9 insertions(+), 24 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_entity.c b/drivers/media/usb/uvc/uvc_entity.c
index 33119dcb7cec..ac386bb547e6 100644
--- a/drivers/media/usb/uvc/uvc_entity.c
+++ b/drivers/media/usb/uvc/uvc_entity.c
@@ -19,19 +19,6 @@

#include "uvcvideo.h"

-/* ------------------------------------------------------------------------
- * Video subdevices registration and unregistration
- */
-
-static int uvc_mc_register_entity(struct uvc_video_chain *chain,
- struct uvc_entity *entity)
-{
- if (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
- return 0;
-
- return v4l2_device_register_subdev(&chain->dev->vdev, &entity->subdev);
-}
-
static int uvc_mc_create_links(struct uvc_video_chain *chain,
struct uvc_entity *entity)
{
@@ -85,7 +72,8 @@ void uvc_mc_cleanup_entity(struct uvc_entity *entity)
media_entity_cleanup(&entity->vdev->entity);
}

-static int uvc_mc_init_entity(struct uvc_entity *entity)
+static int uvc_mc_init_entity(struct uvc_video_chain *chain,
+ struct uvc_entity *entity)
{
int ret;

@@ -96,6 +84,12 @@ static int uvc_mc_init_entity(struct uvc_entity *entity)

ret = media_entity_pads_init(&entity->subdev.entity,
entity->num_pads, entity->pads);
+
+ if (ret < 0)
+ return ret;
+
+ ret = v4l2_device_register_subdev(&chain->dev->vdev,
+ &entity->subdev);
} else if (entity->vdev != NULL) {
ret = media_entity_pads_init(&entity->vdev->entity,
entity->num_pads, entity->pads);
@@ -113,7 +107,7 @@ int uvc_mc_register_entities(struct uvc_video_chain *chain)
int ret;

list_for_each_entry(entity, &chain->entities, chain) {
- ret = uvc_mc_init_entity(entity);
+ ret = uvc_mc_init_entity(chain, entity);
if (ret < 0) {
uvc_printk(KERN_INFO, "Failed to initialize entity for "
"entity %u\n", entity->id);
@@ -122,15 +116,6 @@ int uvc_mc_register_entities(struct uvc_video_chain *chain)
}

list_for_each_entry(entity, &chain->entities, chain) {
- ret = uvc_mc_register_entity(chain, entity);
- if (ret < 0) {
- uvc_printk(KERN_INFO, "Failed to register entity for "
- "entity %u\n", entity->id);
- return ret;
- }
- }
-
- list_for_each_entry(entity, &chain->entities, chain) {
ret = uvc_mc_create_links(chain, entity);
if (ret < 0) {
uvc_printk(KERN_INFO, "Failed to create links for "
--
2.4.3

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