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 <[email protected]>
   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 #include "internal.h"
  18
  19 static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
  20                                       unsigned int *val)
  21 {
  22         struct device *dev = context;
  23         struct i2c_client *i2c = to_i2c_client(dev);
  24         int ret;
  25
  26         if (reg > 0xff)
  27                 return -EINVAL;
  28
  29         ret = i2c_smbus_read_byte_data(i2c, reg);
  30         if (ret < 0)
  31                 return ret;
  32
  33         *val = ret;
  34
  35         return 0;
  36 }
  37
  38 static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
  39                                        unsigned int val)
  40 {
  41         struct device *dev = context;
  42         struct i2c_client *i2c = to_i2c_client(dev);
  43
  44         if (val > 0xff || reg > 0xff)
  45                 return -EINVAL;
  46
  47         return i2c_smbus_write_byte_data(i2c, reg, val);
  48 }
  49
  50 static struct regmap_bus regmap_smbus_byte = {
  51         .reg_write = regmap_smbus_byte_reg_write,
  52         .reg_read = regmap_smbus_byte_reg_read,
  53 };
  54
  55 static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
  56                                       unsigned int *val)
  57 {
  58         struct device *dev = context;
  59         struct i2c_client *i2c = to_i2c_client(dev);
  60         int ret;
  61
  62         if (reg > 0xff)
  63                 return -EINVAL;
  64
  65         ret = i2c_smbus_read_word_data(i2c, reg);
  66         if (ret < 0)
  67                 return ret;
  68
  69         *val = ret;
  70
  71         return 0;
  72 }
  73
  74 static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
  75                                        unsigned int val)
  76 {
  77         struct device *dev = context;
  78         struct i2c_client *i2c = to_i2c_client(dev);
  79
  80         if (val > 0xffff || reg > 0xff)
  81                 return -EINVAL;
  82
  83         return i2c_smbus_write_word_data(i2c, reg, val);
  84 }
  85
  86 static struct regmap_bus regmap_smbus_word = {
  87         .reg_write = regmap_smbus_word_reg_write,
  88         .reg_read = regmap_smbus_word_reg_read,
  89 };
  90
  91 static int regmap_smbus_word_read_swapped(void *context, unsigned int reg,
  92                                           unsigned int *val)
  93 {
  94         struct device *dev = context;
  95         struct i2c_client *i2c = to_i2c_client(dev);
  96         int ret;
  97
  98         if (reg > 0xff)
  99                 return -EINVAL;
 100
 101         ret = i2c_smbus_read_word_swapped(i2c, reg);
 102         if (ret < 0)
 103                 return ret;
 104
 105         *val = ret;
 106
 107         return 0;
 108 }
 109
 110 static int regmap_smbus_word_write_swapped(void *context, unsigned int reg,
 111                                            unsigned int val)
 112 {
 113         struct device *dev = context;
 114         struct i2c_client *i2c = to_i2c_client(dev);
 115
 116         if (val > 0xffff || reg > 0xff)
 117                 return -EINVAL;
 118
 119         return i2c_smbus_write_word_swapped(i2c, reg, val);
 120 }
 121
 122 static struct regmap_bus regmap_smbus_word_swapped = {
 123         .reg_write = regmap_smbus_word_write_swapped,
 124         .reg_read = regmap_smbus_word_read_swapped,
 125 };
 126
 127 static int regmap_i2c_write(void *context, const void *data, size_t count)
 128 {
 129         struct device *dev = context;
 130         struct i2c_client *i2c = to_i2c_client(dev);
 131         int ret;
 132
 133         ret = i2c_master_send(i2c, data, count);
 134         if (ret == count)
 135                 return 0;
 136         else if (ret < 0)
 137                 return ret;
 138         else
 139                 return -EIO;
 140 }
 141
 142 static int regmap_i2c_gather_write(void *context,
 143                                    const void *reg, size_t reg_size,
 144                                    const void *val, size_t val_size)
 145 {
 146         struct device *dev = context;
 147         struct i2c_client *i2c = to_i2c_client(dev);
 148         struct i2c_msg xfer[2];
 149         int ret;
 150
 151         /* If the I2C controller can't do a gather tell the core, it
 152          * will substitute in a linear write for us.
 153          */
 154         if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
 155                 return -ENOTSUPP;
 156
 157         xfer[0].addr = i2c->addr;
 158         xfer[0].flags = 0;
 159         xfer[0].len = reg_size;
 160         xfer[0].buf = (void *)reg;
 161
 162         xfer[1].addr = i2c->addr;
 163         xfer[1].flags = I2C_M_NOSTART;
 164         xfer[1].len = val_size;
 165         xfer[1].buf = (void *)val;
 166
 167         ret = i2c_transfer(i2c->adapter, xfer, 2);
 168         if (ret == 2)
 169                 return 0;
 170         if (ret < 0)
 171                 return ret;
 172         else
 173                 return -EIO;
 174 }
 175
 176 static int regmap_i2c_read(void *context,
 177                            const void *reg, size_t reg_size,
 178                            void *val, size_t val_size)
 179 {
 180         struct device *dev = context;
 181         struct i2c_client *i2c = to_i2c_client(dev);
 182         struct i2c_msg xfer[2];
 183         int ret;
 184
 185         xfer[0].addr = i2c->addr;
 186         xfer[0].flags = 0;
 187         xfer[0].len = reg_size;
 188         xfer[0].buf = (void *)reg;
 189
 190         xfer[1].addr = i2c->addr;
 191         xfer[1].flags = I2C_M_RD;
 192         xfer[1].len = val_size;
 193         xfer[1].buf = val;
 194
 195         ret = i2c_transfer(i2c->adapter, xfer, 2);
 196         if (ret == 2)
 197                 return 0;
 198         else if (ret < 0)
 199                 return ret;
 200         else
 201                 return -EIO;
 202 }
 203
 204 static struct regmap_bus regmap_i2c = {
 205         .write = regmap_i2c_write,
 206         .gather_write = regmap_i2c_gather_write,
 207         .read = regmap_i2c_read,
 208         .reg_format_endian_default = REGMAP_ENDIAN_BIG,
 209         .val_format_endian_default = REGMAP_ENDIAN_BIG,
 210 };
 211
 212 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
 213                                         const struct regmap_config *config)
 214 {
 215         if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
 216                 return &regmap_i2c;
 217         else if (config->val_bits == 16 && config->reg_bits == 8 &&
 218                  i2c_check_functionality(i2c->adapter,
 219                                          I2C_FUNC_SMBUS_WORD_DATA))
 220                 switch (regmap_get_val_endian(&i2c->dev, NULL, config)) {
 221                 case REGMAP_ENDIAN_LITTLE:
 222                         return &regmap_smbus_word;
 223                 case REGMAP_ENDIAN_BIG:
 224                         return &regmap_smbus_word_swapped;
 225                 default:                /* everything else is not supported */
 226                         break;
 227                 }
 228         else if (config->val_bits == 8 && config->reg_bits == 8 &&
 229                  i2c_check_functionality(i2c->adapter,
 230                                          I2C_FUNC_SMBUS_BYTE_DATA))
 231                 return &regmap_smbus_byte;
 232
 233         return ERR_PTR(-ENOTSUPP);
 234 }
 235
 236 /**
 237  * regmap_init_i2c(): Initialise register map
 238  *
 239  * @i2c: Device that will be interacted with
 240  * @config: Configuration for register map
 241  *
 242  * The return value will be an ERR_PTR() on error or a valid pointer to
 243  * a struct regmap.
 244  */
 245 struct regmap *regmap_init_i2c(struct i2c_client *i2c,
 246                                const struct regmap_config *config)
 247 {
 248         const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 249
 250         if (IS_ERR(bus))
 251                 return ERR_CAST(bus);
 252
 253         return regmap_init(&i2c->dev, bus, &i2c->dev, config);
 254 }
 255 EXPORT_SYMBOL_GPL(regmap_init_i2c);
 256
 257 /**
 258  * devm_regmap_init_i2c(): Initialise managed register map
 259  *
 260  * @i2c: Device that will be interacted with
 261  * @config: Configuration for register map
 262  *
 263  * The return value will be an ERR_PTR() on error or a valid pointer
 264  * to a struct regmap.  The regmap will be automatically freed by the
 265  * device management code.
 266  */
 267 struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
 268                                     const struct regmap_config *config)
 269 {
 270         const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 271
 272         if (IS_ERR(bus))
 273                 return ERR_CAST(bus);
 274
 275         return devm_regmap_init(&i2c->dev, bus, &i2c->dev, config);
 276 }
 277 EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
 278
 279 MODULE_LICENSE("GPL");