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authorBoris BREZILLON <boris.brezillon@free-electrons.com>2014-04-21 22:56:59 +0200
committerMark Brown <broonie@linaro.org>2014-04-22 12:57:28 +0100
commitb42261078a91db8a8307db42cad41a619077d1df (patch)
treefa1d655bc813477914a4bca5fd0ca1d6833d2256 /drivers/base/regmap/regmap-i2c.c
parent3ac170376f2c5123414e0267aa0f9cf218965e24 (diff)
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: Boris BREZILLON <boris.brezillon@free-electrons.com> Signed-off-by: Mark Brown <broonie@linaro.org>
Diffstat (limited to 'drivers/base/regmap/regmap-i2c.c')
-rw-r--r--drivers/base/regmap/regmap-i2c.c104
1 files changed, 102 insertions, 2 deletions
diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
index ebd189529760..ca193d1ef47c 100644
--- a/drivers/base/regmap/regmap-i2c.c
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -14,6 +14,79 @@
#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;
@@ -97,6 +170,23 @@ static struct regmap_bus regmap_i2c = {
.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
*
@@ -109,7 +199,12 @@ static struct regmap_bus regmap_i2c = {
struct regmap *regmap_init_i2c(struct i2c_client *i2c,
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);
@@ -126,7 +221,12 @@ EXPORT_SYMBOL_GPL(regmap_init_i2c);
struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
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);