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![Ben Williamson](/assets/img/avatar_default.png)
This driver is glue between the USB gadget interface and the ALSA MIDI interface. It allows us to appear as a MIDI Streaming device to a host system on the other end of a USB cable. This includes linux/usb/audio.h and linux/usb/midi.h containing definitions from the relevant USB specifications for USB audio and USB MIDI devices. The following changes have been made since the first RFC posting: * Bug fixes to endpoint handling. * Workaround for USB_REQ_SET_CONFIGURATION handling, not understood yet. * Added SND and SND_RAWMIDI dependencies in Kconfig. * Moved usb_audio.h and usb_midi.h to usb/*.h * Added module parameters for ALSA card index and id. * Added module parameters for USB descriptor IDs and strings. * Removed some unneeded stuff inherited from zero.c, more to go. * Provide DECLARE_* macros for the variable-length structs. * Use kmalloc instead of usb_ep_alloc_buffer. * Limit source to 80 columns. * Return actual error code instead of -ENOMEM in a few places. Signed-off-by: Ben Williamson <ben.williamson@greyinnovation.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/*
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* <linux/usb/audio.h> -- USB Audio definitions.
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*
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* Copyright (C) 2006 Thumtronics Pty Ltd.
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* Developed for Thumtronics by Grey Innovation
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* Ben Williamson <ben.williamson@greyinnovation.com>
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*
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* This software is distributed under the terms of the GNU General Public
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* License ("GPL") version 2, as published by the Free Software Foundation.
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*
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* This file holds USB constants and structures defined
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* by the USB Device Class Definition for Audio Devices.
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* Comments below reference relevant sections of that document:
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*
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* http://www.usb.org/developers/devclass_docs/audio10.pdf
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*/
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#ifndef __LINUX_USB_AUDIO_H
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#define __LINUX_USB_AUDIO_H
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#include <linux/types.h>
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/* A.2 Audio Interface Subclass Codes */
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#define USB_SUBCLASS_AUDIOCONTROL 0x01
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#define USB_SUBCLASS_AUDIOSTREAMING 0x02
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#define USB_SUBCLASS_MIDISTREAMING 0x03
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/* 4.3.2 Class-Specific AC Interface Descriptor */
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struct usb_ac_header_descriptor {
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__u8 bLength; // 8+n
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__u8 bDescriptorType; // USB_DT_CS_INTERFACE
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__u8 bDescriptorSubtype; // USB_MS_HEADER
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__le16 bcdADC; // 0x0100
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__le16 wTotalLength; // includes Unit and Terminal desc.
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__u8 bInCollection; // n
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__u8 baInterfaceNr[]; // [n]
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} __attribute__ ((packed));
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#define USB_DT_AC_HEADER_SIZE(n) (8+(n))
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/* As above, but more useful for defining your own descriptors: */
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#define DECLARE_USB_AC_HEADER_DESCRIPTOR(n) \
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struct usb_ac_header_descriptor_##n { \
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__u8 bLength; \
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__u8 bDescriptorType; \
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__u8 bDescriptorSubtype; \
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__le16 bcdADC; \
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__le16 wTotalLength; \
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__u8 bInCollection; \
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__u8 baInterfaceNr[n]; \
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} __attribute__ ((packed))
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#endif
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