Commit b4226107 authored by Boris BREZILLON's avatar Boris BREZILLON Committed by Mark Brown

regmap: i2c: fallback to SMBus if the adapter does not support standard I2C

Some I2C adapters are only compatible with the SMBus protocol and do not
support standard I2C transfers.

Fallback to SMBus transfers if we encounter such kind of adapters.
The transfer type is chosen according to the val_bits field in the regmap
config.
Signed-off-by: default avatarBoris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 3ac17037
...@@ -14,6 +14,79 @@ ...@@ -14,6 +14,79 @@
#include <linux/i2c.h> #include <linux/i2c.h>
#include <linux/module.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) static int regmap_i2c_write(void *context, const void *data, size_t count)
{ {
struct device *dev = context; struct device *dev = context;
...@@ -97,6 +170,23 @@ static struct regmap_bus regmap_i2c = { ...@@ -97,6 +170,23 @@ static struct regmap_bus regmap_i2c = {
.read = regmap_i2c_read, .read = regmap_i2c_read,
}; };
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 &regmap_i2c;
else if (config->val_bits == 16 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_WORD_DATA))
return &regmap_smbus_word;
else if (config->val_bits == 8 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_BYTE_DATA))
return &regmap_smbus_byte;
return ERR_PTR(-ENOTSUPP);
}
/** /**
* regmap_init_i2c(): Initialise register map * regmap_init_i2c(): Initialise register map
* *
...@@ -109,7 +199,12 @@ static struct regmap_bus regmap_i2c = { ...@@ -109,7 +199,12 @@ static struct regmap_bus regmap_i2c = {
struct regmap *regmap_init_i2c(struct i2c_client *i2c, struct regmap *regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config) const struct regmap_config *config)
{ {
return regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, 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); EXPORT_SYMBOL_GPL(regmap_init_i2c);
...@@ -126,7 +221,12 @@ EXPORT_SYMBOL_GPL(regmap_init_i2c); ...@@ -126,7 +221,12 @@ EXPORT_SYMBOL_GPL(regmap_init_i2c);
struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c, struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config) const struct regmap_config *config)
{ {
return devm_regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, 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); EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment