1 // SPDX-License-Identifier: GPL-2.0 2 // 3 // Register map access API - I2C support 4 // 5 // Copyright 2011 Wolfson Microelectronics plc 6 // 7 // Author: Mark Brown <broonie@opensource.wolfsonmicro.com> 8 9 #include <linux/regmap.h> 10 #include <linux/i2c.h> 11 #include <linux/module.h> 12 13 #include "internal.h" 14 15 static int regmap_smbus_byte_reg_read(void *context, unsigned int reg, 16 unsigned int *val) 17 { 18 struct device *dev = context; 19 struct i2c_client *i2c = to_i2c_client(dev); 20 int ret; 21 22 if (reg > 0xff) 23 return -EINVAL; 24 25 ret = i2c_smbus_read_byte_data(i2c, reg); 26 if (ret < 0) 27 return ret; 28 29 *val = ret; 30 31 return 0; 32 } 33 34 static int regmap_smbus_byte_reg_write(void *context, unsigned int reg, 35 unsigned int val) 36 { 37 struct device *dev = context; 38 struct i2c_client *i2c = to_i2c_client(dev); 39 40 if (val > 0xff || reg > 0xff) 41 return -EINVAL; 42 43 return i2c_smbus_write_byte_data(i2c, reg, val); 44 } 45 46 static struct regmap_bus regmap_smbus_byte = { 47 .reg_write = regmap_smbus_byte_reg_write, 48 .reg_read = regmap_smbus_byte_reg_read, 49 }; 50 51 static int regmap_smbus_word_reg_read(void *context, unsigned int reg, 52 unsigned int *val) 53 { 54 struct device *dev = context; 55 struct i2c_client *i2c = to_i2c_client(dev); 56 int ret; 57 58 if (reg > 0xff) 59 return -EINVAL; 60 61 ret = i2c_smbus_read_word_data(i2c, reg); 62 if (ret < 0) 63 return ret; 64 65 *val = ret; 66 67 return 0; 68 } 69 70 static int regmap_smbus_word_reg_write(void *context, unsigned int reg, 71 unsigned int val) 72 { 73 struct device *dev = context; 74 struct i2c_client *i2c = to_i2c_client(dev); 75 76 if (val > 0xffff || reg > 0xff) 77 return -EINVAL; 78 79 return i2c_smbus_write_word_data(i2c, reg, val); 80 } 81 82 static struct regmap_bus regmap_smbus_word = { 83 .reg_write = regmap_smbus_word_reg_write, 84 .reg_read = regmap_smbus_word_reg_read, 85 }; 86 87 static int regmap_smbus_word_read_swapped(void *context, unsigned int reg, 88 unsigned int *val) 89 { 90 struct device *dev = context; 91 struct i2c_client *i2c = to_i2c_client(dev); 92 int ret; 93 94 if (reg > 0xff) 95 return -EINVAL; 96 97 ret = i2c_smbus_read_word_swapped(i2c, reg); 98 if (ret < 0) 99 return ret; 100 101 *val = ret; 102 103 return 0; 104 } 105 106 static int regmap_smbus_word_write_swapped(void *context, unsigned int reg, 107 unsigned int val) 108 { 109 struct device *dev = context; 110 struct i2c_client *i2c = to_i2c_client(dev); 111 112 if (val > 0xffff || reg > 0xff) 113 return -EINVAL; 114 115 return i2c_smbus_write_word_swapped(i2c, reg, val); 116 } 117 118 static struct regmap_bus regmap_smbus_word_swapped = { 119 .reg_write = regmap_smbus_word_write_swapped, 120 .reg_read = regmap_smbus_word_read_swapped, 121 }; 122 123 static int regmap_i2c_write(void *context, const void *data, size_t count) 124 { 125 struct device *dev = context; 126 struct i2c_client *i2c = to_i2c_client(dev); 127 int ret; 128 129 ret = i2c_master_send(i2c, data, count); 130 if (ret == count) 131 return 0; 132 else if (ret < 0) 133 return ret; 134 else 135 return -EIO; 136 } 137 138 static int regmap_i2c_gather_write(void *context, 139 const void *reg, size_t reg_size, 140 const void *val, size_t val_size) 141 { 142 struct device *dev = context; 143 struct i2c_client *i2c = to_i2c_client(dev); 144 struct i2c_msg xfer[2]; 145 int ret; 146 147 /* If the I2C controller can't do a gather tell the core, it 148 * will substitute in a linear write for us. 149 */ 150 if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART)) 151 return -ENOTSUPP; 152 153 xfer[0].addr = i2c->addr; 154 xfer[0].flags = 0; 155 xfer[0].len = reg_size; 156 xfer[0].buf = (void *)reg; 157 158 xfer[1].addr = i2c->addr; 159 xfer[1].flags = I2C_M_NOSTART; 160 xfer[1].len = val_size; 161 xfer[1].buf = (void *)val; 162 163 ret = i2c_transfer(i2c->adapter, xfer, 2); 164 if (ret == 2) 165 return 0; 166 if (ret < 0) 167 return ret; 168 else 169 return -EIO; 170 } 171 172 static int regmap_i2c_read(void *context, 173 const void *reg, size_t reg_size, 174 void *val, size_t val_size) 175 { 176 struct device *dev = context; 177 struct i2c_client *i2c = to_i2c_client(dev); 178 struct i2c_msg xfer[2]; 179 int ret; 180 181 xfer[0].addr = i2c->addr; 182 xfer[0].flags = 0; 183 xfer[0].len = reg_size; 184 xfer[0].buf = (void *)reg; 185 186 xfer[1].addr = i2c->addr; 187 xfer[1].flags = I2C_M_RD; 188 xfer[1].len = val_size; 189 xfer[1].buf = val; 190 191 ret = i2c_transfer(i2c->adapter, xfer, 2); 192 if (ret == 2) 193 return 0; 194 else if (ret < 0) 195 return ret; 196 else 197 return -EIO; 198 } 199 200 static struct regmap_bus regmap_i2c = { 201 .write = regmap_i2c_write, 202 .gather_write = regmap_i2c_gather_write, 203 .read = regmap_i2c_read, 204 .reg_format_endian_default = REGMAP_ENDIAN_BIG, 205 .val_format_endian_default = REGMAP_ENDIAN_BIG, 206 }; 207 208 static int regmap_i2c_smbus_i2c_write(void *context, const void *data, 209 size_t count) 210 { 211 struct device *dev = context; 212 struct i2c_client *i2c = to_i2c_client(dev); 213 214 if (count < 1) 215 return -EINVAL; 216 217 --count; 218 return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count, 219 ((u8 *)data + 1)); 220 } 221 222 static int regmap_i2c_smbus_i2c_read(void *context, const void *reg, 223 size_t reg_size, void *val, 224 size_t val_size) 225 { 226 struct device *dev = context; 227 struct i2c_client *i2c = to_i2c_client(dev); 228 int ret; 229 230 if (reg_size != 1 || val_size < 1) 231 return -EINVAL; 232 233 ret = i2c_smbus_read_i2c_block_data(i2c, ((u8 *)reg)[0], val_size, val); 234 if (ret == val_size) 235 return 0; 236 else if (ret < 0) 237 return ret; 238 else 239 return -EIO; 240 } 241 242 static struct regmap_bus regmap_i2c_smbus_i2c_block = { 243 .write = regmap_i2c_smbus_i2c_write, 244 .read = regmap_i2c_smbus_i2c_read, 245 .max_raw_read = I2C_SMBUS_BLOCK_MAX, 246 .max_raw_write = I2C_SMBUS_BLOCK_MAX, 247 }; 248 249 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c, 250 const struct regmap_config *config) 251 { 252 if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C)) 253 return ®map_i2c; 254 else if (config->val_bits == 8 && config->reg_bits == 8 && 255 i2c_check_functionality(i2c->adapter, 256 I2C_FUNC_SMBUS_I2C_BLOCK)) 257 return ®map_i2c_smbus_i2c_block; 258 else if (config->val_bits == 16 && config->reg_bits == 8 && 259 i2c_check_functionality(i2c->adapter, 260 I2C_FUNC_SMBUS_WORD_DATA)) 261 switch (regmap_get_val_endian(&i2c->dev, NULL, config)) { 262 case REGMAP_ENDIAN_LITTLE: 263 return ®map_smbus_word; 264 case REGMAP_ENDIAN_BIG: 265 return ®map_smbus_word_swapped; 266 default: /* everything else is not supported */ 267 break; 268 } 269 else if (config->val_bits == 8 && config->reg_bits == 8 && 270 i2c_check_functionality(i2c->adapter, 271 I2C_FUNC_SMBUS_BYTE_DATA)) 272 return ®map_smbus_byte; 273 274 return ERR_PTR(-ENOTSUPP); 275 } 276 277 struct regmap *__regmap_init_i2c(struct i2c_client *i2c, 278 const struct regmap_config *config, 279 struct lock_class_key *lock_key, 280 const char *lock_name) 281 { 282 const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config); 283 284 if (IS_ERR(bus)) 285 return ERR_CAST(bus); 286 287 return __regmap_init(&i2c->dev, bus, &i2c->dev, config, 288 lock_key, lock_name); 289 } 290 EXPORT_SYMBOL_GPL(__regmap_init_i2c); 291 292 struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c, 293 const struct regmap_config *config, 294 struct lock_class_key *lock_key, 295 const char *lock_name) 296 { 297 const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config); 298 299 if (IS_ERR(bus)) 300 return ERR_CAST(bus); 301 302 return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config, 303 lock_key, lock_name); 304 } 305 EXPORT_SYMBOL_GPL(__devm_regmap_init_i2c); 306 307 MODULE_LICENSE("GPL"); 308