diff options
Diffstat (limited to 'drivers/base/regmap/regmap-i2c.c')
| -rw-r--r-- | drivers/base/regmap/regmap-i2c.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c new file mode 100644 index 00000000000..ca193d1ef47 --- /dev/null +++ b/drivers/base/regmap/regmap-i2c.c @@ -0,0 +1,233 @@ +/* + * 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, +}; + +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"); |