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/*
* Register map access API - I2C support
*
* Copyright 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 version 2 as
* published by the Free Software Foundation.
*/
#include <linux/regmap.h>
#include <linux/i2c.h>
#include <linux/module.h>
static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg > 0xff)
return -EINVAL;
ret = i2c_smbus_read_byte_data(i2c, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
unsigned int val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (val > 0xff || reg > 0xff)
return -EINVAL;
return i2c_smbus_write_byte_data(i2c, reg, val);
}
static struct regmap_bus regmap_smbus_byte = {
.reg_write = regmap_smbus_byte_reg_write,
.reg_read = regmap_smbus_byte_reg_read,
};
static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg > 0xff)
return -EINVAL;
ret = i2c_smbus_read_word_data(i2c, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
unsigned int val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (val > 0xffff || reg > 0xff)
return -EINVAL;
return i2c_smbus_write_word_data(i2c, reg, val);
}
static struct regmap_bus regmap_smbus_word = {
.reg_write = regmap_smbus_word_reg_write,
.reg_read = regmap_smbus_word_reg_read,
};
static int regmap_i2c_write(void *context, const void *data, size_t count)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
ret = i2c_master_send(i2c, data, count);
if (ret == count)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static int regmap_i2c_gather_write(void *context,
const void *reg, size_t reg_size,
const void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
struct i2c_msg xfer[2];
int ret;
/* If the I2C controller can't do a gather tell the core, it
* will substitute in a linear write for us.
*/
if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
return -ENOTSUPP;
xfer[0].addr = i2c->addr;
xfer[0].flags = 0;
xfer[0].len = reg_size;
xfer[0].buf = (void *)reg;
xfer[1].addr = i2c->addr;
xfer[1].flags = I2C_M_NOSTART;
xfer[1].len = val_size;
xfer[1].buf = (void *)val;
ret = i2c_transfer(i2c->adapter, xfer, 2);
if (ret == 2)
return 0;
if (ret < 0)
return ret;
else
return -EIO;
}
static int regmap_i2c_read(void *context,
const void *reg, size_t reg_size,
void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
struct i2c_msg xfer[2];
int ret;
xfer[0].addr = i2c->addr;
xfer[0].flags = 0;
xfer[0].len = reg_size;
xfer[0].buf = (void *)reg;
xfer[1].addr = i2c->addr;
xfer[1].flags = I2C_M_RD;
xfer[1].len = val_size;
xfer[1].buf = val;
ret = i2c_transfer(i2c->adapter, xfer, 2);
if (ret == 2)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static struct regmap_bus regmap_i2c = {
.write = regmap_i2c_write,
.gather_write = regmap_i2c_gather_write,
.read = regmap_i2c_read,
.reg_format_endian_default = REGMAP_ENDIAN_BIG,
.val_format_endian_default = REGMAP_ENDIAN_BIG,
};
static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
const struct regmap_config *config)
{
if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
return ®map_i2c;
else if (config->val_bits == 16 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_WORD_DATA))
return ®map_smbus_word;
else if (config->val_bits == 8 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_BYTE_DATA))
return ®map_smbus_byte;
return ERR_PTR(-ENOTSUPP);
}
/**
* regmap_init_i2c(): Initialise register map
*
* @i2c: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer to
* a struct regmap.
*/
struct regmap *regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config)
{
const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
if (IS_ERR(bus))
return ERR_CAST(bus);
return regmap_init(&i2c->dev, bus, &i2c->dev, config);
}
EXPORT_SYMBOL_GPL(regmap_init_i2c);
/**
* devm_regmap_init_i2c(): Initialise managed register map
*
* @i2c: Device that will be interacted with
* @config: Configuration for register map
*
* The return value will be an ERR_PTR() on error or a valid pointer
* to a struct regmap. The regmap will be automatically freed by the
* device management code.
*/
struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config)
{
const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
if (IS_ERR(bus))
return ERR_CAST(bus);
return devm_regmap_init(&i2c->dev, bus, &i2c->dev, config);
}
EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
MODULE_LICENSE("GPL");
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