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(void *context, const void *data, size_t count)
  19 {
  20         struct device *dev = context;
  21         struct i2c_client *i2c = to_i2c_client(dev);
  22         int ret;
  23
  24         ret = i2c_master_send(i2c, data, count);
  25         if (ret == count)
  26                 return 0;
  27         else if (ret < 0)
  28                 return ret;
  29         else
  30                 return -EIO;
  31 }
  32
  33 static int regmap_i2c_gather_write(void *context,
  34                                    const void *reg, size_t reg_size,
  35                                    const void *val, size_t val_size)
  36 {
  37         struct device *dev = context;
  38         struct i2c_client *i2c = to_i2c_client(dev);
  39         struct i2c_msg xfer[2];
  40         int ret;
  41
  42         /* If the I2C controller can't do a gather tell the core, it
  43          * will substitute in a linear write for us.
  44          */
  45         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
  46                 return -ENOTSUPP;
  47
  48         xfer[0].addr = i2c->addr;
  49         xfer[0].flags = 0;
  50         xfer[0].len = reg_size;
  51         xfer[0].buf = (void *)reg;
  52
  53         xfer[1].addr = i2c->addr;
  54         xfer[1].flags = I2C_M_NOSTART;
  55         xfer[1].len = val_size;
  56         xfer[1].buf = (void *)val;
  57
  58         ret = i2c_transfer(i2c->adapter, xfer, 2);
  59         if (ret == 2)
  60                 return 0;
  61         if (ret < 0)
  62                 return ret;
  63         else
  64                 return -EIO;
  65 }
  66
  67 static int regmap_i2c_read(void *context,
  68                            const void *reg, size_t reg_size,
  69                            void *val, size_t val_size)
  70 {
  71         struct device *dev = context;
  72         struct i2c_client *i2c = to_i2c_client(dev);
  73         struct i2c_msg xfer[2];
  74         int ret;
  75
  76         xfer[0].addr = i2c->addr;
  77         xfer[0].flags = 0;
  78         xfer[0].len = reg_size;
  79         xfer[0].buf = (void *)reg;
  80
  81         xfer[1].addr = i2c->addr;
  82         xfer[1].flags = I2C_M_RD;
  83         xfer[1].len = val_size;
  84         xfer[1].buf = val;
  85
  86         ret = i2c_transfer(i2c->adapter, xfer, 2);
  87         if (ret == 2)
  88                 return 0;
  89         else if (ret < 0)
  90                 return ret;
  91         else
  92                 return -EIO;
  93 }
  94
  95 static struct regmap_bus regmap_i2c = {
  96         .write = regmap_i2c_write,
  97         .gather_write = regmap_i2c_gather_write,
  98         .read = regmap_i2c_read,
  99 };
 100
 101 /**
 102  * regmap_init_i2c(): Initialise register map
 103  *
 104  * @i2c: Device that will be interacted with
 105  * @config: Configuration for register map
 106  *
 107  * The return value will be an ERR_PTR() on error or a valid pointer to
 108  * a struct regmap.
 109  */
 110 struct regmap *regmap_init_i2c(struct i2c_client *i2c,
 111                                const struct regmap_config *config)
 112 {
 113         return regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
 114 }
 115 EXPORT_SYMBOL_GPL(regmap_init_i2c);
 116
 117 /**
 118  * devm_regmap_init_i2c(): Initialise managed register map
 119  *
 120  * @i2c: Device that will be interacted with
 121  * @config: Configuration for register map
 122  *
 123  * The return value will be an ERR_PTR() on error or a valid pointer
 124  * to a struct regmap.  The regmap will be automatically freed by the
 125  * device management code.
 126  */
 127 struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
 128                                     const struct regmap_config *config)
 129 {
 130         return devm_regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
 131 }
 132 EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
 133
 134 MODULE_LICENSE("GPL");