linux/sound/usb/helper.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>

#include "usbaudio.h"
#include "helper.h"
#include "quirks.h"

/*
 * combine bytes and get an integer value
 */
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
{ … }

/*
 * parse descriptor buffer and return the pointer starting the given
 * descriptor type.
 */
void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
{ … }

/*
 * find a class-specified interface descriptor with the given subtype.
 */
void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
{ … }

/*
 * Wrapper for usb_control_msg().
 * Allocates a temp buffer to prevent dmaing from/to the stack.
 */
int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
		    __u8 requesttype, __u16 value, __u16 index, void *data,
		    __u16 size)
{ … }

unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
					 struct usb_host_interface *alts)
{ … }

struct usb_host_interface *
snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)
{ … }