regmap-i2c.c

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/*
 * Register map access API - I2C support
 *
 * Copyright 2011 Wolfson Microelectronics plc
 *
 * Author: Mark Brown <[email protected]>
 *
 * 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>
#include <linux/init.h>

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,
};

struct regmap *regmap_init_i2c(struct i2c_client *i2c,
                   const struct regmap_config *config)
{
    return regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
}
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);
}
EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);

MODULE_LICENSE("GPL");