1. 根目录:
2. sound
3. soc
4. soc-cache.c

/*
 * soc-cache.c  --  ASoC register cache helpers
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 */

#include <sound/soc.h>
#include <linux/export.h>
#include <linux/slab.h>

int snd_soc_cache_init(struct snd_soc_codec *codec)
{
	const struct snd_soc_codec_driver *codec_drv = codec->driver;
	size_t reg_size;

	reg_size = codec_drv->reg_cache_size * codec_drv->reg_word_size;

	if (!reg_size)
		return 0;

	dev_dbg(codec->dev, "ASoC: Initializing cache for %s codec\n",
				codec->component.name);

	if (codec_drv->reg_cache_default)
		codec->reg_cache = kmemdup(codec_drv->reg_cache_default,
					   reg_size, GFP_KERNEL);
	else
		codec->reg_cache = kzalloc(reg_size, GFP_KERNEL);
	if (!codec->reg_cache)
		return -ENOMEM;

	return 0;
}

/*
 * NOTE: keep in mind that this function might be called
 * multiple times.
 */
int snd_soc_cache_exit(struct snd_soc_codec *codec)
{
	dev_dbg(codec->dev, "ASoC: Destroying cache for %s codec\n",
			codec->component.name);
	kfree(codec->reg_cache);
	codec->reg_cache = NULL;
	return 0;
}