diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2015-02-03 10:01:19 -0800 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2015-02-04 20:48:13 +0000 |
| commit | 5892ded23c8e9e015b01347222ba4de8a80e7ce2 (patch) | |
| tree | 24a8457b9c79c08289add18d09c07ed6cb22c9ae /drivers/base | |
| parent | 3c174d29263b1954171cf857a9bf59dcbe527875 (diff) | |
regmap: Fix i2c word access when using SMBus access functions
SMBus access functions assume that 16-bit values are formatted as
little endian numbers. The direct i2c access functions in regmap,
however, assume that 16-bit values are formatted as big endian numbers.
As a result, the current code returns different values if an i2c chip's
16-bit registers are accessed through i2c access functions vs. SMBus
access functions.
Use regmap_smbus_read_word_swapped and regmap_smbus_write_word_swapped
for 16-bit SMBus accesses if a chip is configured as REGMAP_ENDIAN_BIG.
If the chip is configured as REGMAP_ENDIAN_LITTLE, keep using
regmap_smbus_write_word_data and regmap_smbus_read_word_data. Otherwise
reject registration if the controller does not support direct i2c accesses.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/regmap/regmap-i2c.c | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index 053150a7f9f2..4b76e33110a2 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -14,6 +14,7 @@ #include <linux/i2c.h> #include <linux/module.h> +#include "internal.h" static int regmap_smbus_byte_reg_read(void *context, unsigned int reg, unsigned int *val) @@ -87,6 +88,42 @@ static struct regmap_bus regmap_smbus_word = { .reg_read = regmap_smbus_word_reg_read, }; +static int regmap_smbus_word_read_swapped(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_swapped(i2c, reg); + if (ret < 0) + return ret; + + *val = ret; + + return 0; +} + +static int regmap_smbus_word_write_swapped(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_swapped(i2c, reg, val); +} + +static struct regmap_bus regmap_smbus_word_swapped = { + .reg_write = regmap_smbus_word_write_swapped, + .reg_read = regmap_smbus_word_read_swapped, +}; + static int regmap_i2c_write(void *context, const void *data, size_t count) { struct device *dev = context; @@ -180,7 +217,14 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *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; + switch (regmap_get_val_endian(&i2c->dev, NULL, config)) { + case REGMAP_ENDIAN_LITTLE: + return ®map_smbus_word; + case REGMAP_ENDIAN_BIG: + return ®map_smbus_word_swapped; + default: /* everything else is not supported */ + break; + } else if (config->val_bits == 8 && config->reg_bits == 8 && i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |