drivers/base/regmap/regmap-i2c.c

   1 /*
   2  * Register map access API - I2C support
   3  *
   4  * Copyright 2011 Wolfson Microelectronics plc
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/regmap.h>
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17
  18 static int regmap_i2c_write(struct device *dev, const void *data, size_t count)
  19 {
  20         struct i2c_client *i2c = to_i2c_client(dev);
  21         int ret;
  22
  23         ret = i2c_master_send(i2c, data, count);
  24         if (ret == count)
  25                 return 0;
  26         else if (ret < 0)
  27                 return ret;
  28         else
  29                 return -EIO;
  30 }
  31
  32 static int regmap_i2c_gather_write(struct device *dev,
  33                                    const void *reg, size_t reg_size,
  34                                    const void *val, size_t val_size)
  35 {
  36         struct i2c_client *i2c = to_i2c_client(dev);
  37         struct i2c_msg xfer[2];
  38         int ret;
  39
  40         /* If the I2C controller can't do a gather tell the core, it
  41          * will substitute in a linear write for us.
  42          */
  43         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING))
  44                 return -ENOTSUPP;
  45
  46         xfer[0].addr = i2c->addr;
  47         xfer[0].flags = 0;
  48         xfer[0].len = reg_size;
  49         xfer[0].buf = (void *)reg;
  50
  51         xfer[1].addr = i2c->addr;
  52         xfer[1].flags = I2C_M_NOSTART;
  53         xfer[1].len = val_size;
  54         xfer[1].buf = (void *)val;
  55
  56         ret = i2c_transfer(i2c->adapter, xfer, 2);
  57         if (ret == 2)
  58                 return 0;
  59         if (ret < 0)
  60                 return ret;
  61         else
  62                 return -EIO;
  63 }
  64
  65 static int regmap_i2c_read(struct device *dev,
  66                            const void *reg, size_t reg_size,
  67                            void *val, size_t val_size)
  68 {
  69         struct i2c_client *i2c = to_i2c_client(dev);
  70         struct i2c_msg xfer[2];
  71         int ret;
  72
  73         xfer[0].addr = i2c->addr;
  74         xfer[0].flags = 0;
  75         xfer[0].len = reg_size;
  76         xfer[0].buf = (void *)reg;
  77
  78         xfer[1].addr = i2c->addr;
  79         xfer[1].flags = I2C_M_RD;
  80         xfer[1].len = val_size;
  81         xfer[1].buf = val;
  82
  83         ret = i2c_transfer(i2c->adapter, xfer, 2);
  84         if (ret == 2)
  85                 return 0;
  86         else if (ret < 0)
  87                 return ret;
  88         else
  89                 return -EIO;
  90 }
  91
  92 static struct regmap_bus regmap_i2c = {
  93         .write = regmap_i2c_write,
  94         .gather_write = regmap_i2c_gather_write,
  95         .read = regmap_i2c_read,
  96 };
  97
  98 /**
  99  * regmap_init_i2c(): Initialise register map
 100  *
 101  * @i2c: Device that will be interacted with
 102  * @config: Configuration for register map
 103  *
 104  * The return value will be an ERR_PTR() on error or a valid pointer to
 105  * a struct regmap.
 106  */
 107 struct regmap *regmap_init_i2c(struct i2c_client *i2c,
 108                                const struct regmap_config *config)
 109 {
 110         return regmap_init(&i2c->dev, &regmap_i2c, config);
 111 }
 112 EXPORT_SYMBOL_GPL(regmap_init_i2c);
 113
 114 MODULE_LICENSE("GPL");