diff options
Diffstat (limited to 'include/uapi/linux/usb/audio.h')
| -rw-r--r-- | include/uapi/linux/usb/audio.h | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/include/uapi/linux/usb/audio.h b/include/uapi/linux/usb/audio.h index ddc5396800aa..c917c53070d5 100644 --- a/include/uapi/linux/usb/audio.h +++ b/include/uapi/linux/usb/audio.h @@ -341,7 +341,7 @@ struct uac_feature_unit_descriptor { __u8 bUnitID; __u8 bSourceID; __u8 bControlSize; - __u8 bmaControls[0]; /* variable length */ + __u8 bmaControls[]; /* variable length */ } __attribute__((packed)); static inline __u8 uac_feature_unit_iFeature(struct uac_feature_unit_descriptor *desc) @@ -450,6 +450,43 @@ static inline __u8 *uac_processing_unit_specific(struct uac_processing_unit_desc } } +/* + * Extension Unit (XU) has almost compatible layout with Processing Unit, but + * on UAC2, it has a different bmControls size (bControlSize); it's 1 byte for + * XU while 2 bytes for PU. The last iExtension field is a one-byte index as + * well as iProcessing field of PU. + */ +static inline __u8 uac_extension_unit_bControlSize(struct uac_processing_unit_descriptor *desc, + int protocol) +{ + switch (protocol) { + case UAC_VERSION_1: + return desc->baSourceID[desc->bNrInPins + 4]; + case UAC_VERSION_2: + return 1; /* in UAC2, this value is constant */ + case UAC_VERSION_3: + return 4; /* in UAC3, this value is constant */ + default: + return 1; + } +} + +static inline __u8 uac_extension_unit_iExtension(struct uac_processing_unit_descriptor *desc, + int protocol) +{ + __u8 control_size = uac_extension_unit_bControlSize(desc, protocol); + + switch (protocol) { + case UAC_VERSION_1: + case UAC_VERSION_2: + default: + return *(uac_processing_unit_bmControls(desc, protocol) + + control_size); + case UAC_VERSION_3: + return 0; /* UAC3 does not have this field */ + } +} + /* 4.5.2 Class-Specific AS Interface Descriptor */ struct uac1_as_header_descriptor { __u8 bLength; /* in bytes: 7 */ |