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linux-next/sound/soc/soc-io.c
Mark Brown 9dfdd5abcf ASoC: io: Don't dereference regmap if we failed to get one
Avoids a crash in invalid configurations.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
2012-06-23 12:11:32 +01:00

176 lines
4.6 KiB
C

/*
* soc-io.c -- ASoC register I/O helpers
*
* Copyright 2009-2011 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 <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/regmap.h>
#include <linux/export.h>
#include <sound/soc.h>
#include <trace/events/asoc.h>
#ifdef CONFIG_REGMAP
static int hw_write(struct snd_soc_codec *codec, unsigned int reg,
unsigned int value)
{
int ret;
if (!snd_soc_codec_volatile_register(codec, reg) &&
reg < codec->driver->reg_cache_size &&
!codec->cache_bypass) {
ret = snd_soc_cache_write(codec, reg, value);
if (ret < 0)
return -1;
}
if (codec->cache_only) {
codec->cache_sync = 1;
return 0;
}
return regmap_write(codec->control_data, reg, value);
}
static unsigned int hw_read(struct snd_soc_codec *codec, unsigned int reg)
{
int ret;
unsigned int val;
if (reg >= codec->driver->reg_cache_size ||
snd_soc_codec_volatile_register(codec, reg) ||
codec->cache_bypass) {
if (codec->cache_only)
return -1;
ret = regmap_read(codec->control_data, reg, &val);
if (ret == 0)
return val;
else
return -1;
}
ret = snd_soc_cache_read(codec, reg, &val);
if (ret < 0)
return -1;
return val;
}
/* Primitive bulk write support for soc-cache. The data pointed to by
* `data' needs to already be in the form the hardware expects. Any
* data written through this function will not go through the cache as
* it only handles writing to volatile or out of bounds registers.
*
* This is currently only supported for devices using the regmap API
* wrappers.
*/
static int snd_soc_hw_bulk_write_raw(struct snd_soc_codec *codec,
unsigned int reg,
const void *data, size_t len)
{
/* To ensure that we don't get out of sync with the cache, check
* whether the base register is volatile or if we've directly asked
* to bypass the cache. Out of bounds registers are considered
* volatile.
*/
if (!codec->cache_bypass
&& !snd_soc_codec_volatile_register(codec, reg)
&& reg < codec->driver->reg_cache_size)
return -EINVAL;
return regmap_raw_write(codec->control_data, reg, data, len);
}
/**
* snd_soc_codec_set_cache_io: Set up standard I/O functions.
*
* @codec: CODEC to configure.
* @addr_bits: Number of bits of register address data.
* @data_bits: Number of bits of data per register.
* @control: Control bus used.
*
* Register formats are frequently shared between many I2C and SPI
* devices. In order to promote code reuse the ASoC core provides
* some standard implementations of CODEC read and write operations
* which can be set up using this function.
*
* The caller is responsible for allocating and initialising the
* actual cache.
*
* Note that at present this code cannot be used by CODECs with
* volatile registers.
*/
int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
int addr_bits, int data_bits,
enum snd_soc_control_type control)
{
struct regmap_config config;
int ret;
memset(&config, 0, sizeof(config));
codec->write = hw_write;
codec->read = hw_read;
codec->bulk_write_raw = snd_soc_hw_bulk_write_raw;
config.reg_bits = addr_bits;
config.val_bits = data_bits;
switch (control) {
#if defined(CONFIG_REGMAP_I2C) || defined(CONFIG_REGMAP_I2C_MODULE)
case SND_SOC_I2C:
codec->control_data = regmap_init_i2c(to_i2c_client(codec->dev),
&config);
break;
#endif
#if defined(CONFIG_REGMAP_SPI) || defined(CONFIG_REGMAP_SPI_MODULE)
case SND_SOC_SPI:
codec->control_data = regmap_init_spi(to_spi_device(codec->dev),
&config);
break;
#endif
case SND_SOC_REGMAP:
/* Device has made its own regmap arrangements */
codec->using_regmap = true;
if (!codec->control_data)
codec->control_data = dev_get_regmap(codec->dev, NULL);
if (codec->control_data) {
ret = regmap_get_val_bytes(codec->control_data);
/* Errors are legitimate for non-integer byte
* multiples */
if (ret > 0)
codec->val_bytes = ret;
}
break;
default:
return -EINVAL;
}
if (IS_ERR(codec->control_data))
return PTR_ERR(codec->control_data);
return 0;
}
EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);
#else
int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
int addr_bits, int data_bits,
enum snd_soc_control_type control)
{
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);
#endif