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
  17
  18 static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
  19                                       unsigned int *val)
  20 {
  21         struct device *dev = context;
  22         struct i2c_client *i2c = to_i2c_client(dev);
  23         int ret;
  24
  25         if (reg > 0xff)
  26                 return -EINVAL;
  27
  28         ret = i2c_smbus_read_byte_data(i2c, reg);
  29         if (ret < 0)
  30                 return ret;
  31
  32         *val = ret;
  33
  34         return 0;
  35 }
  36
  37 static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
  38                                        unsigned int val)
  39 {
  40         struct device *dev = context;
  41         struct i2c_client *i2c = to_i2c_client(dev);
  42
  43         if (val > 0xff || reg > 0xff)
  44                 return -EINVAL;
  45
  46         return i2c_smbus_write_byte_data(i2c, reg, val);
  47 }
  48
  49 static struct regmap_bus regmap_smbus_byte = {
  50         .reg_write = regmap_smbus_byte_reg_write,
  51         .reg_read = regmap_smbus_byte_reg_read,
  52 };
  53
  54 static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
  55                                       unsigned int *val)
  56 {
  57         struct device *dev = context;
  58         struct i2c_client *i2c = to_i2c_client(dev);
  59         int ret;
  60
  61         if (reg > 0xff)
  62                 return -EINVAL;
  63
  64         ret = i2c_smbus_read_word_data(i2c, reg);
  65         if (ret < 0)
  66                 return ret;
  67
  68         *val = ret;
  69
  70         return 0;
  71 }
  72
  73 static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
  74                                        unsigned int val)
  75 {
  76         struct device *dev = context;
  77         struct i2c_client *i2c = to_i2c_client(dev);
  78
  79         if (val > 0xffff || reg > 0xff)
  80                 return -EINVAL;
  81
  82         return i2c_smbus_write_word_data(i2c, reg, val);
  83 }
  84
  85 static struct regmap_bus regmap_smbus_word = {
  86         .reg_write = regmap_smbus_word_reg_write,
  87         .reg_read = regmap_smbus_word_reg_read,
  88 };
  89
  90 static int regmap_i2c_write(void *context, const void *data, size_t count)
  91 {
  92         struct device *dev = context;
  93         struct i2c_client *i2c = to_i2c_client(dev);
  94         int ret;
  95
  96         ret = i2c_master_send(i2c, data, count);
  97         if (ret == count)
  98                 return 0;
  99         else if (ret < 0)
 100                 return ret;
 101         else
 102                 return -EIO;
 103 }
 104
 105 static int regmap_i2c_gather_write(void *context,
 106                                    const void *reg, size_t reg_size,
 107                                    const void *val, size_t val_size)
 108 {
 109         struct device *dev = context;
 110         struct i2c_client *i2c = to_i2c_client(dev);
 111         struct i2c_msg xfer[2];
 112         int ret;
 113
 114         /* If the I2C controller can't do a gather tell the core, it
 115          * will substitute in a linear write for us.
 116          */
 117         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
 118                 return -ENOTSUPP;
 119
 120         xfer[0].addr = i2c->addr;
 121         xfer[0].flags = 0;
 122         xfer[0].len = reg_size;
 123         xfer[0].buf = (void *)reg;
 124
 125         xfer[1].addr = i2c->addr;
 126         xfer[1].flags = I2C_M_NOSTART;
 127         xfer[1].len = val_size;
 128         xfer[1].buf = (void *)val;
 129
 130         ret = i2c_transfer(i2c->adapter, xfer, 2);
 131         if (ret == 2)
 132                 return 0;
 133         if (ret < 0)
 134                 return ret;
 135         else
 136                 return -EIO;
 137 }
 138
 139 static int regmap_i2c_read(void *context,
 140                            const void *reg, size_t reg_size,
 141                            void *val, size_t val_size)
 142 {
 143         struct device *dev = context;
 144         struct i2c_client *i2c = to_i2c_client(dev);
 145         struct i2c_msg xfer[2];
 146         int ret;
 147
 148         xfer[0].addr = i2c->addr;
 149         xfer[0].flags = 0;
 150         xfer[0].len = reg_size;
 151         xfer[0].buf = (void *)reg;
 152
 153         xfer[1].addr = i2c->addr;
 154         xfer[1].flags = I2C_M_RD;
 155         xfer[1].len = val_size;
 156         xfer[1].buf = val;
 157
 158         ret = i2c_transfer(i2c->adapter, xfer, 2);
 159         if (ret == 2)
 160                 return 0;
 161         else if (ret < 0)
 162                 return ret;
 163         else
 164                 return -EIO;
 165 }
 166
 167 static struct regmap_bus regmap_i2c = {
 168         .write = regmap_i2c_write,
 169         .gather_write = regmap_i2c_gather_write,
 170         .read = regmap_i2c_read,
 171         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
 172         .val_format_endian_default = REGMAP_ENDIAN_BIG,
 173 };
 174
 175 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
 176                                         const struct regmap_config *config)
 177 {
 178         if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
 179                 return &regmap_i2c;
 180         else if (config->val_bits == 16 && config->reg_bits == 8 &&
 181                  i2c_check_functionality(i2c->adapter,
 182                                          I2C_FUNC_SMBUS_WORD_DATA))
 183                 return &regmap_smbus_word;
 184         else if (config->val_bits == 8 && config->reg_bits == 8 &&
 185                  i2c_check_functionality(i2c->adapter,
 186                                          I2C_FUNC_SMBUS_BYTE_DATA))
 187                 return &regmap_smbus_byte;
 188
 189         return ERR_PTR(-ENOTSUPP);
 190 }
 191
 192 /**
 193  * regmap_init_i2c(): Initialise register map
 194  *
 195  * @i2c: Device that will be interacted with
 196  * @config: Configuration for register map
 197  *
 198  * The return value will be an ERR_PTR() on error or a valid pointer to
 199  * a struct regmap.
 200  */
 201 struct regmap *regmap_init_i2c(struct i2c_client *i2c,
 202                                const struct regmap_config *config)
 203 {
 204         const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 205
 206         if (IS_ERR(bus))
 207                 return ERR_CAST(bus);
 208
 209         return regmap_init(&i2c->dev, bus, &i2c->dev, config);
 210 }
 211 EXPORT_SYMBOL_GPL(regmap_init_i2c);
 212
 213 /**
 214  * devm_regmap_init_i2c(): Initialise managed register map
 215  *
 216  * @i2c: Device that will be interacted with
 217  * @config: Configuration for register map
 218  *
 219  * The return value will be an ERR_PTR() on error or a valid pointer
 220  * to a struct regmap.  The regmap will be automatically freed by the
 221  * device management code.
 222  */
 223 struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
 224                                     const struct regmap_config *config)
 225 {
 226         const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 227
 228         if (IS_ERR(bus))
 229                 return ERR_CAST(bus);
 230
 231         return devm_regmap_init(&i2c->dev, bus, &i2c->dev, config);
 232 }
 233 EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
 234
 235 MODULE_LICENSE("GPL");