1. 根目录:
2. sound
3. usb
4. format.h

#ifndef __USBAUDIO_FORMAT_H
#define __USBAUDIO_FORMAT_H

int snd_usb_parse_audio_format(struct snd_usb_audio *chip,
			       struct audioformat *fp, unsigned int format,
			       struct uac_format_type_i_continuous_descriptor *fmt,
			       int stream);

#endif /*  __USBAUDIO_FORMAT_H */