linux-stable/sound/usb/helper.h
Takashi Iwai e42a09bc52 ALSA: usb-audio: Add snd_usb_get_host_interface() helper
Add a helper function to retrieve the usb_host_interface object from
the given interface and altsetting number pair, which is a commonly
used procedure in the driver code.

No functional changes, just minor code refactoring.

Tested-by: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-17-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-11-23 15:13:47 +01:00

40 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __USBAUDIO_HELPER_H
#define __USBAUDIO_HELPER_H
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size);
void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype);
void *snd_usb_find_csint_desc(void *descstart, int desclen, void *after, u8 dsubtype);
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);
/*
* retrieve usb_interface descriptor from the host interface
* (conditional for compatibility with the older API)
*/
#define get_iface_desc(iface) (&(iface)->desc)
#define get_endpoint(alt,ep) (&(alt)->endpoint[ep].desc)
#define get_ep_desc(ep) (&(ep)->desc)
#define get_cfg_desc(cfg) (&(cfg)->desc)
#define snd_usb_get_speed(dev) ((dev)->speed)
static inline int snd_usb_ctrl_intf(struct snd_usb_audio *chip)
{
return get_iface_desc(chip->ctrl_intf)->bInterfaceNumber;
}
/* in validate.c */
bool snd_usb_validate_audio_desc(void *p, int protocol);
bool snd_usb_validate_midi_desc(void *p);
#endif /* __USBAUDIO_HELPER_H */