[PATCH 2/6] media: uvcvideo: Add UVC_CTRL_FLAG_ENTITY_GET_CUR

[Ricardo Ribalda]

This flag allows controls to get their current value from an entity
defined function instead of via a query to the USB device.

Signed-off-by: Ricardo Ribalda <riba...@chromium.org>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 17 +++++++++++++----
 include/uapi/linux/uvcvideo.h    |  1 +
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 7acdc055613b..0a8835742d49 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1001,10 +1001,19 @@ static int __uvc_ctrl_get(struct uvc_video_chain *chain,
                return -EACCES;
 
        if (!ctrl->loaded) {
-               ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, ctrl->entity->id,
-                               chain->dev->intfnum, ctrl->info.selector,
-                               uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
-                               ctrl->info.size);
+               if (ctrl->info.flags & UVC_CTRL_FLAG_ENTITY_GET_CUR) {
+                       if (!ctrl->entity->get_cur)
+                               return -EINVAL;
+                       ret = ctrl->entity->get_cur(ctrl->entity,
+                                       ctrl->info.selector,
+                                       uvc_ctrl_data(ctrl, 
UVC_CTRL_DATA_CURRENT),
+                                       ctrl->info.size);
+               } else {
+                       ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, 
ctrl->entity->id,
+                                            chain->dev->intfnum, 
ctrl->info.selector,
+                                            uvc_ctrl_data(ctrl, 
UVC_CTRL_DATA_CURRENT),
+                                            ctrl->info.size);
+               }
                if (ret < 0)
                        return ret;
 
diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h
index 69b636290c31..cb91797d2a09 100644
--- a/include/uapi/linux/uvcvideo.h
+++ b/include/uapi/linux/uvcvideo.h
@@ -32,6 +32,7 @@
 #define UVC_CTRL_FLAG_ASYNCHRONOUS     (1 << 8)
 /* Entity queries */
 #define UVC_CTRL_FLAG_ENTITY_GET_INFO  (1 << 9)
+#define UVC_CTRL_FLAG_ENTITY_GET_CUR   (1 << 10)
 
 #define UVC_CTRL_FLAG_GET_RANGE \
        (UVC_CTRL_FLAG_GET_CUR | UVC_CTRL_FLAG_GET_MIN | \
-- 
2.29.0.rc1.297.gfa9743e501-goog