[media] uvcvideo: Document the struct uvc_xu_control_query query field
Several developers have reported that the lack of macros for the struct
uvc_xu_control_query query field in uvcvideo.h was confusing and forced
them to look at the driver source code to find out what applications
were supposed to pass in that field.
Add a comment to the header to clarify the expected usage of the query
field.
Reported-by: Paulo Assis <pj.assis@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/linux/uvcvideo.h b/include/linux/uvcvideo.h
index f46a53f..3b08186 100644
--- a/include/linux/uvcvideo.h
+++ b/include/linux/uvcvideo.h
@@ -58,7 +58,8 @@
struct uvc_xu_control_query {
__u8 unit;
__u8 selector;
- __u8 query;
+ __u8 query; /* Video Class-Specific Request Code, */
+ /* defined in linux/usb/video.h A.8. */
__u16 size;
__u8 __user *data;
};