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

[Ricardo Ribalda <ribalda@chromium.org>]

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 <ribalda@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