linux/sound/usb/clock.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Clock domain and sample rate management functions
 */

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/usb/audio-v3.h>

#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>

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

uac23_clock_source_desc;

uac23_clock_selector_desc;

uac23_clock_multiplier_desc;

#define GET_VAL(p, proto, field) …

static void *find_uac_clock_desc(struct usb_host_interface *iface, int id,
				 bool (*validator)(void *, int, int),
				 u8 type, int proto)
{ … }

static bool validate_clock_source(void *p, int id, int proto)
{ … }

static bool validate_clock_selector(void *p, int id, int proto)
{ … }

static bool validate_clock_multiplier(void *p, int id, int proto)
{ … }

#define DEFINE_FIND_HELPER(name, obj, validator, type2, type3) …

DEFINE_FIND_HELPER(snd_usb_find_clock_source,
		   union uac23_clock_source_desc, validate_clock_source,
		   UAC2_CLOCK_SOURCE, UAC3_CLOCK_SOURCE);
DEFINE_FIND_HELPER(snd_usb_find_clock_selector,
		   union uac23_clock_selector_desc, validate_clock_selector,
		   UAC2_CLOCK_SELECTOR, UAC3_CLOCK_SELECTOR);
DEFINE_FIND_HELPER(snd_usb_find_clock_multiplier,
		   union uac23_clock_multiplier_desc, validate_clock_multiplier,
		   UAC2_CLOCK_MULTIPLIER, UAC3_CLOCK_MULTIPLIER);

static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
{ … }

static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,
					unsigned char pin)
{ … }

static bool uac_clock_source_is_valid_quirk(struct snd_usb_audio *chip,
					    const struct audioformat *fmt,
					    int source_id)
{ … }

static bool uac_clock_source_is_valid(struct snd_usb_audio *chip,
				      const struct audioformat *fmt,
				      int source_id)
{ … }

static int __uac_clock_find_source(struct snd_usb_audio *chip,
				   const struct audioformat *fmt, int entity_id,
				   unsigned long *visited, bool validate)
{ … }

/*
 * For all kinds of sample rate settings and other device queries,
 * the clock source (end-leaf) must be used. However, clock selectors,
 * clock multipliers and sample rate converters may be specified as
 * clock source input to terminal. This functions walks the clock path
 * to its end and tries to find the source.
 *
 * The 'visited' bitfield is used internally to detect recursive loops.
 *
 * Returns the clock source UnitID (>=0) on success, or an error.
 */
int snd_usb_clock_find_source(struct snd_usb_audio *chip,
			      const struct audioformat *fmt, bool validate)
{ … }

static int set_sample_rate_v1(struct snd_usb_audio *chip,
			      const struct audioformat *fmt, int rate)
{ … }

static int get_sample_rate_v2v3(struct snd_usb_audio *chip, int iface,
			      int altsetting, int clock)
{ … }

/*
 * Try to set the given sample rate:
 *
 * Return 0 if the clock source is read-only, the actual rate on success,
 * or a negative error code.
 *
 * This function gets called from format.c to validate each sample rate, too.
 * Hence no message is shown upon error
 */
int snd_usb_set_sample_rate_v2v3(struct snd_usb_audio *chip,
				 const struct audioformat *fmt,
				 int clock, int rate)
{ … }

static int set_sample_rate_v2v3(struct snd_usb_audio *chip,
				const struct audioformat *fmt, int rate)
{ … }

int snd_usb_init_sample_rate(struct snd_usb_audio *chip,
			     const struct audioformat *fmt, int rate)
{ … }