include/linux/usb/audio.h

/*
 * <linux/usb/audio.h> -- USB Audio definitions.
 *
 * Copyright (C) 2006 Thumtronics Pty Ltd.
 * Developed for Thumtronics by Grey Innovation
 * Ben Williamson <ben.williamson@greyinnovation.com>
 *
 * This software is distributed under the terms of the GNU General Public
 * License ("GPL") version 2, as published by the Free Software Foundation.
 *
 * This file holds USB constants and structures defined
 * by the USB Device Class Definition for Audio Devices.
 * Comments below reference relevant sections of that document:
 *
 * http://www.usb.org/developers/devclass_docs/audio10.pdf
 */

#ifndef __LINUX_USB_AUDIO_H
#define __LINUX_USB_AUDIO_H

#include <linux/types.h>

/* A.2 Audio Interface Subclass Codes */
#define USB_SUBCLASS_AUDIOCONTROL	0x01
#define USB_SUBCLASS_AUDIOSTREAMING	0x02
#define USB_SUBCLASS_MIDISTREAMING	0x03

/* 4.3.2  Class-Specific AC Interface Descriptor */
struct usb_ac_header_descriptor {
	__u8  bLength;			// 8+n
	__u8  bDescriptorType;		// USB_DT_CS_INTERFACE
	__u8  bDescriptorSubtype;	// USB_MS_HEADER
	__le16 bcdADC;			// 0x0100
	__le16 wTotalLength;		// includes Unit and Terminal desc.
	__u8  bInCollection;		// n
	__u8  baInterfaceNr[];		// [n]
} __attribute__ ((packed));

#define USB_DT_AC_HEADER_SIZE(n)	(8+(n))

/* As above, but more useful for defining your own descriptors: */
#define DECLARE_USB_AC_HEADER_DESCRIPTOR(n) 			\
struct usb_ac_header_descriptor_##n {				\
	__u8  bLength;						\
	__u8  bDescriptorType;					\
	__u8  bDescriptorSubtype;				\
	__le16 bcdADC;						\
	__le16 wTotalLength;					\
	__u8  bInCollection;					\
	__u8  baInterfaceNr[n];					\
} __attribute__ ((packed))

#endif