drivers/base/regmap/regmap.c

   1 /*
   2  * Register map access API
   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/slab.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/err.h>
  17
  18 #include <linux/regmap.h>
  19
  20 struct regmap;
  21
  22 struct regmap_format {
  23         size_t buf_size;
  24         size_t reg_bytes;
  25         size_t val_bytes;
  26         void (*format_write)(struct regmap *map,
  27                              unsigned int reg, unsigned int val);
  28         void (*format_reg)(void *buf, unsigned int reg);
  29         void (*format_val)(void *buf, unsigned int val);
  30         unsigned int (*parse_val)(void *buf);
  31 };
  32
  33 struct regmap {
  34         struct mutex lock;
  35
  36         struct device *dev; /* Device we do I/O on */
  37         void *work_buf;     /* Scratch buffer used to format I/O */
  38         struct regmap_format format;  /* Buffer format */
  39         const struct regmap_bus *bus;
  40 };
  41
  42 static void regmap_format_4_12_write(struct regmap *map,
  43                                      unsigned int reg, unsigned int val)
  44 {
  45         __be16 *out = map->work_buf;
  46         *out = cpu_to_be16((reg << 12) | val);
  47 }
  48
  49 static void regmap_format_7_9_write(struct regmap *map,
  50                                     unsigned int reg, unsigned int val)
  51 {
  52         __be16 *out = map->work_buf;
  53         *out = cpu_to_be16((reg << 9) | val);
  54 }
  55
  56 static void regmap_format_8(void *buf, unsigned int val)
  57 {
  58         u8 *b = buf;
  59
  60         b[0] = val;
  61 }
  62
  63 static void regmap_format_16(void *buf, unsigned int val)
  64 {
  65         __be16 *b = buf;
  66
  67         b[0] = cpu_to_be16(val);
  68 }
  69
  70 static unsigned int regmap_parse_8(void *buf)
  71 {
  72         u8 *b = buf;
  73
  74         return b[0];
  75 }
  76
  77 static unsigned int regmap_parse_16(void *buf)
  78 {
  79         __be16 *b = buf;
  80
  81         b[0] = be16_to_cpu(b[0]);
  82
  83         return b[0];
  84 }
  85
  86 /**
  87  * regmap_init(): Initialise register map
  88  *
  89  * @dev: Device that will be interacted with
  90  * @bus: Bus-specific callbacks to use with device
  91  * @config: Configuration for register map
  92  *
  93  * The return value will be an ERR_PTR() on error or a valid pointer to
  94  * a struct regmap.  This function should generally not be called
  95  * directly, it should be called by bus-specific init functions.
  96  */
  97 struct regmap *regmap_init(struct device *dev,
  98                            const struct regmap_bus *bus,
  99                            const struct regmap_config *config)
 100 {
 101         struct regmap *map;
 102         int ret = -EINVAL;
 103
 104         if (!bus || !config)
 105                 return NULL;
 106
 107         map = kzalloc(sizeof(*map), GFP_KERNEL);
 108         if (map == NULL) {
 109                 ret = -ENOMEM;
 110                 goto err;
 111         }
 112
 113         mutex_init(&map->lock);
 114         map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
 115         map->format.reg_bytes = config->reg_bits / 8;
 116         map->format.val_bytes = config->val_bits / 8;
 117         map->dev = dev;
 118         map->bus = bus;
 119
 120         switch (config->reg_bits) {
 121         case 4:
 122                 switch (config->val_bits) {
 123                 case 12:
 124                         map->format.format_write = regmap_format_4_12_write;
 125                         break;
 126                 default:
 127                         goto err_map;
 128                 }
 129                 break;
 130
 131         case 7:
 132                 switch (config->val_bits) {
 133                 case 9:
 134                         map->format.format_write = regmap_format_7_9_write;
 135                         break;
 136                 default:
 137                         goto err_map;
 138                 }
 139                 break;
 140
 141         case 8:
 142                 map->format.format_reg = regmap_format_8;
 143                 break;
 144
 145         case 16:
 146                 map->format.format_reg = regmap_format_16;
 147                 break;
 148
 149         default:
 150                 goto err_map;
 151         }
 152
 153         switch (config->val_bits) {
 154         case 8:
 155                 map->format.format_val = regmap_format_8;
 156                 map->format.parse_val = regmap_parse_8;
 157                 break;
 158         case 16:
 159                 map->format.format_val = regmap_format_16;
 160                 map->format.parse_val = regmap_parse_16;
 161                 break;
 162         }
 163
 164         if (!map->format.format_write &&
 165             !(map->format.format_reg && map->format.format_val))
 166                 goto err_map;
 167
 168         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 169         if (map->work_buf == NULL) {
 170                 ret = -ENOMEM;
 171                 goto err_bus;
 172         }
 173
 174         return map;
 175
 176 err_bus:
 177         module_put(map->bus->owner);
 178 err_map:
 179         kfree(map);
 180 err:
 181         return ERR_PTR(ret);
 182 }
 183 EXPORT_SYMBOL_GPL(regmap_init);
 184
 185 /**
 186  * regmap_exit(): Free a previously allocated register map
 187  */
 188 void regmap_exit(struct regmap *map)
 189 {
 190         kfree(map->work_buf);
 191         module_put(map->bus->owner);
 192         kfree(map);
 193 }
 194 EXPORT_SYMBOL_GPL(regmap_exit);
 195
 196 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 197                              const void *val, size_t val_len)
 198 {
 199         void *buf;
 200         int ret = -ENOTSUPP;
 201         size_t len;
 202
 203         map->format.format_reg(map->work_buf, reg);
 204
 205         /* Try to do a gather write if we can */
 206         if (map->bus->gather_write)
 207                 ret = map->bus->gather_write(map->dev, map->work_buf,
 208                                              map->format.reg_bytes,
 209                                              val, val_len);
 210
 211         /* Otherwise fall back on linearising by hand. */
 212         if (ret == -ENOTSUPP) {
 213                 len = map->format.reg_bytes + val_len;
 214                 buf = kmalloc(len, GFP_KERNEL);
 215                 if (!buf)
 216                         return -ENOMEM;
 217
 218                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 219                 memcpy(buf + map->format.reg_bytes, val, val_len);
 220                 ret = map->bus->write(map->dev, buf, len);
 221
 222                 kfree(buf);
 223         }
 224
 225         return ret;
 226 }
 227
 228 static int _regmap_write(struct regmap *map, unsigned int reg,
 229                          unsigned int val)
 230 {
 231         BUG_ON(!map->format.format_write && !map->format.format_val);
 232
 233         if (map->format.format_write) {
 234                 map->format.format_write(map, reg, val);
 235
 236                 return map->bus->write(map->dev, map->work_buf,
 237                                        map->format.buf_size);
 238         } else {
 239                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 240                                        val);
 241                 return _regmap_raw_write(map, reg,
 242                                          map->work_buf + map->format.reg_bytes,
 243                                          map->format.val_bytes);
 244         }
 245 }
 246
 247 /**
 248  * regmap_write(): Write a value to a single register
 249  *
 250  * @map: Register map to write to
 251  * @reg: Register to write to
 252  * @val: Value to be written
 253  *
 254  * A value of zero will be returned on success, a negative errno will
 255  * be returned in error cases.
 256  */
 257 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 258 {
 259         int ret;
 260
 261         mutex_lock(&map->lock);
 262
 263         ret = _regmap_write(map, reg, val);
 264
 265         mutex_unlock(&map->lock);
 266
 267         return ret;
 268 }
 269 EXPORT_SYMBOL_GPL(regmap_write);
 270
 271 /**
 272  * regmap_raw_write(): Write raw values to one or more registers
 273  *
 274  * @map: Register map to write to
 275  * @reg: Initial register to write to
 276  * @val: Block of data to be written, laid out for direct transmission to the
 277  *       device
 278  * @val_len: Length of data pointed to by val.
 279  *
 280  * This function is intended to be used for things like firmware
 281  * download where a large block of data needs to be transferred to the
 282  * device.  No formatting will be done on the data provided.
 283  *
 284  * A value of zero will be returned on success, a negative errno will
 285  * be returned in error cases.
 286  */
 287 int regmap_raw_write(struct regmap *map, unsigned int reg,
 288                      const void *val, size_t val_len)
 289 {
 290         int ret;
 291
 292         mutex_lock(&map->lock);
 293
 294         ret = _regmap_raw_write(map, reg, val, val_len);
 295
 296         mutex_unlock(&map->lock);
 297
 298         return ret;
 299 }
 300 EXPORT_SYMBOL_GPL(regmap_raw_write);
 301
 302 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 303                             unsigned int val_len)
 304 {
 305         u8 *u8 = map->work_buf;
 306         int ret;
 307
 308         map->format.format_reg(map->work_buf, reg);
 309
 310         /*
 311          * Some buses flag reads by setting the high bits in the
 312          * register addresss; since it's always the high bits for all
 313          * current formats we can do this here rather than in
 314          * formatting.  This may break if we get interesting formats.
 315          */
 316         if (map->bus->read_flag_mask)
 317                 u8[0] |= map->bus->read_flag_mask;
 318
 319         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 320                              val, val_len);
 321         if (ret != 0)
 322                 return ret;
 323
 324         return 0;
 325 }
 326
 327 static int _regmap_read(struct regmap *map, unsigned int reg,
 328                         unsigned int *val)
 329 {
 330         int ret;
 331
 332         if (!map->format.parse_val)
 333                 return -EINVAL;
 334
 335         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 336         if (ret == 0)
 337                 *val = map->format.parse_val(map->work_buf);
 338
 339         return ret;
 340 }
 341
 342 /**
 343  * regmap_read(): Read a value from a single register
 344  *
 345  * @map: Register map to write to
 346  * @reg: Register to be read from
 347  * @val: Pointer to store read value
 348  *
 349  * A value of zero will be returned on success, a negative errno will
 350  * be returned in error cases.
 351  */
 352 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 353 {
 354         int ret;
 355
 356         mutex_lock(&map->lock);
 357
 358         ret = _regmap_read(map, reg, val);
 359
 360         mutex_unlock(&map->lock);
 361
 362         return ret;
 363 }
 364 EXPORT_SYMBOL_GPL(regmap_read);
 365
 366 /**
 367  * regmap_raw_read(): Read raw data from the device
 368  *
 369  * @map: Register map to write to
 370  * @reg: First register to be read from
 371  * @val: Pointer to store read value
 372  * @val_len: Size of data to read
 373  *
 374  * A value of zero will be returned on success, a negative errno will
 375  * be returned in error cases.
 376  */
 377 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 378                     size_t val_len)
 379 {
 380         int ret;
 381
 382         mutex_lock(&map->lock);
 383
 384         ret = _regmap_raw_read(map, reg, val, val_len);
 385
 386         mutex_unlock(&map->lock);
 387
 388         return ret;
 389 }
 390 EXPORT_SYMBOL_GPL(regmap_raw_read);
 391
 392 /**
 393  * regmap_bulk_read(): Read multiple registers from the device
 394  *
 395  * @map: Register map to write to
 396  * @reg: First register to be read from
 397  * @val: Pointer to store read value, in native register size for device
 398  * @val_count: Number of registers to read
 399  *
 400  * A value of zero will be returned on success, a negative errno will
 401  * be returned in error cases.
 402  */
 403 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 404                      size_t val_count)
 405 {
 406         int ret, i;
 407         size_t val_bytes = map->format.val_bytes;
 408
 409         if (!map->format.parse_val)
 410                 return -EINVAL;
 411
 412         ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 413         if (ret != 0)
 414                 return ret;
 415
 416         for (i = 0; i < val_count * val_bytes; i += val_bytes)
 417                 map->format.parse_val(val + i);
 418
 419         return 0;
 420 }
 421 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 422
 423 /**
 424  * remap_update_bits: Perform a read/modify/write cycle on the register map
 425  *
 426  * @map: Register map to update
 427  * @reg: Register to update
 428  * @mask: Bitmask to change
 429  * @val: New value for bitmask
 430  *
 431  * Returns zero for success, a negative number on error.
 432  */
 433 int regmap_update_bits(struct regmap *map, unsigned int reg,
 434                        unsigned int mask, unsigned int val)
 435 {
 436         int ret;
 437         unsigned int tmp;
 438
 439         mutex_lock(&map->lock);
 440
 441         ret = _regmap_read(map, reg, &tmp);
 442         if (ret != 0)
 443                 goto out;
 444
 445         tmp &= ~mask;
 446         tmp |= val & mask;
 447
 448         ret = _regmap_write(map, reg, tmp);
 449
 450 out:
 451         mutex_unlock(&map->lock);
 452
 453         return ret;
 454 }
 455 EXPORT_SYMBOL_GPL(regmap_update_bits);