media: uvcvideo: Allow entity-defined get_info and get_cur

Allows controls to get their properties and current value
from an entity-defined function instead of via a query to the USB
device.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/usb/uvc/uvc_ctrl.c

@@ -980,10 +980,20 @@ 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,
+		if (ctrl->entity->get_cur) {
+			ret = ctrl->entity->get_cur(chain->dev,
+				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;
 
@@ -1692,8 +1702,12 @@ static int uvc_ctrl_get_flags(struct uvc_device *dev,
 	if (data == NULL)
 		return -ENOMEM;
 
-	ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id, dev->intfnum,
-			     info->selector, data, 1);
+	if (ctrl->entity->get_info)
+		ret = ctrl->entity->get_info(dev, ctrl->entity,
+					     ctrl->info.selector, data);
+	else
+		ret = uvc_query_ctrl(dev, UVC_GET_INFO, ctrl->entity->id,
+				     dev->intfnum, info->selector, data, 1);
 	if (!ret)
 		info->flags |= (data[0] & UVC_CONTROL_CAP_GET ?
 				UVC_CTRL_FLAG_GET_CUR : 0)

drivers/media/usb/uvc/uvcvideo.h

@@ -358,6 +358,11 @@ struct uvc_entity {
 	u8 bNrInPins;
 	u8 *baSourceID;
 
+	int (*get_info)(struct uvc_device *dev, struct uvc_entity *entity,
+			u8 cs, u8 *caps);
+	int (*get_cur)(struct uvc_device *dev, struct uvc_entity *entity,
+		       u8 cs, void *data, u16 size);
+
 	unsigned int ncontrols;
 	struct uvc_control *controls;
 };