1 files changed, 16 insertions, 1 deletions

diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
index 383b94ba8c20..964cb603f7c7 100644
--- a/include/linux/usb/audio-v2.h
+++ b/include/linux/usb/audio-v2.h
@@ -18,6 +18,21 @@
 /* v1.0 and v2.0 of this standard have many things in common. For the rest
  * of the definitions, please refer to audio.h */
 
+/*
+ * bmControl field decoders
+ *
+ * From the USB Audio spec v2.0:
+ *
+ *   bmaControls() is a (ch+1)-element array of 4-byte bitmaps,
+ *   each containing a set of bit pairs. If a Control is present,
+ *   it must be Host readable. If a certain Control is not
+ *   present then the bit pair must be set to 0b00.
+ *   If a Control is present but read-only, the bit pair must be
+ *   set to 0b01. If a Control is also Host programmable, the bit
+ *   pair must be set to 0b11. The value 0b10 is not allowed.
+ *
+ */
+
 static inline bool uac2_control_is_readable(u32 bmControls, u8 control)
 {
         return (bmControls >> (control * 2)) & 0x1;
@@ -121,7 +136,7 @@ struct uac2_feature_unit_descriptor {
 
 /* 4.9.2 Class-Specific AS Interface Descriptor */
 
-struct uac_as_header_descriptor_v2 {
+struct uac2_as_header_descriptor {
         __u8 bLength;
         __u8 bDescriptorType;
         __u8 bDescriptorSubtype;