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 #define CREATE_TRACE_POINTS
  19 #include <trace/events/regmap.h>
  20
  21 #include "internal.h"
  22
  23 bool regmap_writeable(struct regmap *map, unsigned int reg)
  24 {
  25         if (map->max_register && reg > map->max_register)
  26                 return false;
  27
  28         if (map->writeable_reg)
  29                 return map->writeable_reg(map->dev, reg);
  30
  31         return true;
  32 }
  33
  34 bool regmap_readable(struct regmap *map, unsigned int reg)
  35 {
  36         if (map->max_register && reg > map->max_register)
  37                 return false;
  38
  39         if (map->readable_reg)
  40                 return map->readable_reg(map->dev, reg);
  41
  42         return true;
  43 }
  44
  45 bool regmap_volatile(struct regmap *map, unsigned int reg)
  46 {
  47         if (map->max_register && reg > map->max_register)
  48                 return false;
  49
  50         if (map->volatile_reg)
  51                 return map->volatile_reg(map->dev, reg);
  52
  53         return true;
  54 }
  55
  56 bool regmap_precious(struct regmap *map, unsigned int reg)
  57 {
  58         if (map->max_register && reg > map->max_register)
  59                 return false;
  60
  61         if (map->precious_reg)
  62                 return map->precious_reg(map->dev, reg);
  63
  64         return false;
  65 }
  66
  67 static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
  68         unsigned int num)
  69 {
  70         unsigned int i;
  71
  72         for (i = 0; i < num; i++)
  73                 if (!regmap_volatile(map, reg + i))
  74                         return false;
  75
  76         return true;
  77 }
  78
  79 static void regmap_format_4_12_write(struct regmap *map,
  80                                      unsigned int reg, unsigned int val)
  81 {
  82         __be16 *out = map->work_buf;
  83         *out = cpu_to_be16((reg << 12) | val);
  84 }
  85
  86 static void regmap_format_7_9_write(struct regmap *map,
  87                                     unsigned int reg, unsigned int val)
  88 {
  89         __be16 *out = map->work_buf;
  90         *out = cpu_to_be16((reg << 9) | val);
  91 }
  92
  93 static void regmap_format_8(void *buf, unsigned int val)
  94 {
  95         u8 *b = buf;
  96
  97         b[0] = val;
  98 }
  99
 100 static void regmap_format_16(void *buf, unsigned int val)
 101 {
 102         __be16 *b = buf;
 103
 104         b[0] = cpu_to_be16(val);
 105 }
 106
 107 static unsigned int regmap_parse_8(void *buf)
 108 {
 109         u8 *b = buf;
 110
 111         return b[0];
 112 }
 113
 114 static unsigned int regmap_parse_16(void *buf)
 115 {
 116         __be16 *b = buf;
 117
 118         b[0] = be16_to_cpu(b[0]);
 119
 120         return b[0];
 121 }
 122
 123 /**
 124  * regmap_init(): Initialise register map
 125  *
 126  * @dev: Device that will be interacted with
 127  * @bus: Bus-specific callbacks to use with device
 128  * @config: Configuration for register map
 129  *
 130  * The return value will be an ERR_PTR() on error or a valid pointer to
 131  * a struct regmap.  This function should generally not be called
 132  * directly, it should be called by bus-specific init functions.
 133  */
 134 struct regmap *regmap_init(struct device *dev,
 135                            const struct regmap_bus *bus,
 136                            const struct regmap_config *config)
 137 {
 138         struct regmap *map;
 139         int ret = -EINVAL;
 140
 141         if (!bus || !config)
 142                 return NULL;
 143
 144         map = kzalloc(sizeof(*map), GFP_KERNEL);
 145         if (map == NULL) {
 146                 ret = -ENOMEM;
 147                 goto err;
 148         }
 149
 150         mutex_init(&map->lock);
 151         map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
 152         map->format.reg_bytes = config->reg_bits / 8;
 153         map->format.val_bytes = config->val_bits / 8;
 154         map->dev = dev;
 155         map->bus = bus;
 156         map->max_register = config->max_register;
 157         map->writeable_reg = config->writeable_reg;
 158         map->readable_reg = config->readable_reg;
 159         map->volatile_reg = config->volatile_reg;
 160         map->precious_reg = config->precious_reg;
 161         map->cache_type = config->cache_type;
 162         map->reg_defaults = config->reg_defaults;
 163         map->num_reg_defaults = config->num_reg_defaults;
 164         map->num_reg_defaults_raw = config->num_reg_defaults_raw;
 165         map->reg_defaults_raw = config->reg_defaults_raw;
 166         map->cache_size_raw = (config->val_bits / 8) * config->num_reg_defaults_raw;
 167         map->cache_word_size = config->val_bits / 8;
 168
 169         if (config->read_flag_mask || config->write_flag_mask) {
 170                 map->read_flag_mask = config->read_flag_mask;
 171                 map->write_flag_mask = config->write_flag_mask;
 172         } else {
 173                 map->read_flag_mask = bus->read_flag_mask;
 174         }
 175
 176         switch (config->reg_bits) {
 177         case 4:
 178                 switch (config->val_bits) {
 179                 case 12:
 180                         map->format.format_write = regmap_format_4_12_write;
 181                         break;
 182                 default:
 183                         goto err_map;
 184                 }
 185                 break;
 186
 187         case 7:
 188                 switch (config->val_bits) {
 189                 case 9:
 190                         map->format.format_write = regmap_format_7_9_write;
 191                         break;
 192                 default:
 193                         goto err_map;
 194                 }
 195                 break;
 196
 197         case 8:
 198                 map->format.format_reg = regmap_format_8;
 199                 break;
 200
 201         case 16:
 202                 map->format.format_reg = regmap_format_16;
 203                 break;
 204
 205         default:
 206                 goto err_map;
 207         }
 208
 209         switch (config->val_bits) {
 210         case 8:
 211                 map->format.format_val = regmap_format_8;
 212                 map->format.parse_val = regmap_parse_8;
 213                 break;
 214         case 16:
 215                 map->format.format_val = regmap_format_16;
 216                 map->format.parse_val = regmap_parse_16;
 217                 break;
 218         }
 219
 220         if (!map->format.format_write &&
 221             !(map->format.format_reg && map->format.format_val))
 222                 goto err_map;
 223
 224         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 225         if (map->work_buf == NULL) {
 226                 ret = -ENOMEM;
 227                 goto err_map;
 228         }
 229
 230         ret = regcache_init(map);
 231         if (ret < 0)
 232                 goto err_map;
 233
 234         regmap_debugfs_init(map);
 235
 236         return map;
 237
 238 err_map:
 239         kfree(map);
 240 err:
 241         return ERR_PTR(ret);
 242 }
 243 EXPORT_SYMBOL_GPL(regmap_init);
 244
 245 /**
 246  * regmap_exit(): Free a previously allocated register map
 247  */
 248 void regmap_exit(struct regmap *map)
 249 {
 250         regcache_exit(map);
 251         regmap_debugfs_exit(map);
 252         kfree(map->work_buf);
 253         kfree(map);
 254 }
 255 EXPORT_SYMBOL_GPL(regmap_exit);
 256
 257 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 258                              const void *val, size_t val_len)
 259 {
 260         u8 *u8 = map->work_buf;
 261         void *buf;
 262         int ret = -ENOTSUPP;
 263         size_t len;
 264         int i;
 265
 266         /* Check for unwritable registers before we start */
 267         if (map->writeable_reg)
 268                 for (i = 0; i < val_len / map->format.val_bytes; i++)
 269                         if (!map->writeable_reg(map->dev, reg + i))
 270                                 return -EINVAL;
 271
 272         map->format.format_reg(map->work_buf, reg);
 273
 274         u8[0] |= map->write_flag_mask;
 275
 276         trace_regmap_hw_write_start(map->dev, reg,
 277                                     val_len / map->format.val_bytes);
 278
 279         /* If we're doing a single register write we can probably just
 280          * send the work_buf directly, otherwise try to do a gather
 281          * write.
 282          */
 283         if (val == map->work_buf + map->format.reg_bytes)
 284                 ret = map->bus->write(map->dev, map->work_buf,
 285                                       map->format.reg_bytes + val_len);
 286         else if (map->bus->gather_write)
 287                 ret = map->bus->gather_write(map->dev, map->work_buf,
 288                                              map->format.reg_bytes,
 289                                              val, val_len);
 290
 291         /* If that didn't work fall back on linearising by hand. */
 292         if (ret == -ENOTSUPP) {
 293                 len = map->format.reg_bytes + val_len;
 294                 buf = kmalloc(len, GFP_KERNEL);
 295                 if (!buf)
 296                         return -ENOMEM;
 297
 298                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 299                 memcpy(buf + map->format.reg_bytes, val, val_len);
 300                 ret = map->bus->write(map->dev, buf, len);
 301
 302                 kfree(buf);
 303         }
 304
 305         trace_regmap_hw_write_done(map->dev, reg,
 306                                    val_len / map->format.val_bytes);
 307
 308         return ret;
 309 }
 310
 311 int _regmap_write(struct regmap *map, unsigned int reg,
 312                   unsigned int val)
 313 {
 314         int ret;
 315         BUG_ON(!map->format.format_write && !map->format.format_val);
 316
 317         if (!map->cache_bypass) {
 318                 ret = regcache_write(map, reg, val);
 319                 if (ret != 0)
 320                         return ret;
 321                 if (map->cache_only) {
 322                         map->cache_dirty = true;
 323                         return 0;
 324                 }
 325         }
 326
 327         trace_regmap_reg_write(map->dev, reg, val);
 328
 329         if (map->format.format_write) {
 330                 map->format.format_write(map, reg, val);
 331
 332                 trace_regmap_hw_write_start(map->dev, reg, 1);
 333
 334                 ret = map->bus->write(map->dev, map->work_buf,
 335                                       map->format.buf_size);
 336
 337                 trace_regmap_hw_write_done(map->dev, reg, 1);
 338
 339                 return ret;
 340         } else {
 341                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 342                                        val);
 343                 return _regmap_raw_write(map, reg,
 344                                          map->work_buf + map->format.reg_bytes,
 345                                          map->format.val_bytes);
 346         }
 347 }
 348
 349 /**
 350  * regmap_write(): Write a value to a single register
 351  *
 352  * @map: Register map to write to
 353  * @reg: Register to write to
 354  * @val: Value to be written
 355  *
 356  * A value of zero will be returned on success, a negative errno will
 357  * be returned in error cases.
 358  */
 359 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 360 {
 361         int ret;
 362
 363         mutex_lock(&map->lock);
 364
 365         ret = _regmap_write(map, reg, val);
 366
 367         mutex_unlock(&map->lock);
 368
 369         return ret;
 370 }
 371 EXPORT_SYMBOL_GPL(regmap_write);
 372
 373 /**
 374  * regmap_raw_write(): Write raw values to one or more registers
 375  *
 376  * @map: Register map to write to
 377  * @reg: Initial register to write to
 378  * @val: Block of data to be written, laid out for direct transmission to the
 379  *       device
 380  * @val_len: Length of data pointed to by val.
 381  *
 382  * This function is intended to be used for things like firmware
 383  * download where a large block of data needs to be transferred to the
 384  * device.  No formatting will be done on the data provided.
 385  *
 386  * A value of zero will be returned on success, a negative errno will
 387  * be returned in error cases.
 388  */
 389 int regmap_raw_write(struct regmap *map, unsigned int reg,
 390                      const void *val, size_t val_len)
 391 {
 392         int ret;
 393
 394         WARN_ON(map->cache_type != REGCACHE_NONE);
 395
 396         mutex_lock(&map->lock);
 397
 398         ret = _regmap_raw_write(map, reg, val, val_len);
 399
 400         mutex_unlock(&map->lock);
 401
 402         return ret;
 403 }
 404 EXPORT_SYMBOL_GPL(regmap_raw_write);
 405
 406 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 407                             unsigned int val_len)
 408 {
 409         u8 *u8 = map->work_buf;
 410         int ret;
 411
 412         map->format.format_reg(map->work_buf, reg);
 413
 414         /*
 415          * Some buses or devices flag reads by setting the high bits in the
 416          * register addresss; since it's always the high bits for all
 417          * current formats we can do this here rather than in
 418          * formatting.  This may break if we get interesting formats.
 419          */
 420         u8[0] |= map->read_flag_mask;
 421
 422         trace_regmap_hw_read_start(map->dev, reg,
 423                                    val_len / map->format.val_bytes);
 424
 425         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 426                              val, val_len);
 427
 428         trace_regmap_hw_read_done(map->dev, reg,
 429                                   val_len / map->format.val_bytes);
 430
 431         return ret;
 432 }
 433
 434 static int _regmap_read(struct regmap *map, unsigned int reg,
 435                         unsigned int *val)
 436 {
 437         int ret;
 438
 439         if (!map->format.parse_val)
 440                 return -EINVAL;
 441
 442         if (!map->cache_bypass) {
 443                 ret = regcache_read(map, reg, val);
 444                 if (ret == 0)
 445                         return 0;
 446         }
 447
 448         if (map->cache_only)
 449                 return -EBUSY;
 450
 451         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 452         if (ret == 0) {
 453                 *val = map->format.parse_val(map->work_buf);
 454                 trace_regmap_reg_read(map->dev, reg, *val);
 455         }
 456
 457         return ret;
 458 }
 459
 460 /**
 461  * regmap_read(): Read a value from a single register
 462  *
 463  * @map: Register map to write to
 464  * @reg: Register to be read from
 465  * @val: Pointer to store read value
 466  *
 467  * A value of zero will be returned on success, a negative errno will
 468  * be returned in error cases.
 469  */
 470 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 471 {
 472         int ret;
 473
 474         mutex_lock(&map->lock);
 475
 476         ret = _regmap_read(map, reg, val);
 477
 478         mutex_unlock(&map->lock);
 479
 480         return ret;
 481 }
 482 EXPORT_SYMBOL_GPL(regmap_read);
 483
 484 /**
 485  * regmap_raw_read(): Read raw data from the device
 486  *
 487  * @map: Register map to write to
 488  * @reg: First register to be read from
 489  * @val: Pointer to store read value
 490  * @val_len: Size of data to read
 491  *
 492  * A value of zero will be returned on success, a negative errno will
 493  * be returned in error cases.
 494  */
 495 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 496                     size_t val_len)
 497 {
 498         size_t val_count = val_len / map->format.val_bytes;
 499         int ret;
 500
 501         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 502                 map->cache_type != REGCACHE_NONE);
 503
 504         mutex_lock(&map->lock);
 505
 506         ret = _regmap_raw_read(map, reg, val, val_len);
 507
 508         mutex_unlock(&map->lock);
 509
 510         return ret;
 511 }
 512 EXPORT_SYMBOL_GPL(regmap_raw_read);
 513
 514 /**
 515  * regmap_bulk_read(): Read multiple registers from the device
 516  *
 517  * @map: Register map to write to
 518  * @reg: First register to be read from
 519  * @val: Pointer to store read value, in native register size for device
 520  * @val_count: Number of registers to read
 521  *
 522  * A value of zero will be returned on success, a negative errno will
 523  * be returned in error cases.
 524  */
 525 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 526                      size_t val_count)
 527 {
 528         int ret, i;
 529         size_t val_bytes = map->format.val_bytes;
 530         bool vol = regmap_volatile_range(map, reg, val_count);
 531
 532         if (!map->format.parse_val)
 533                 return -EINVAL;
 534
 535         if (vol || map->cache_type == REGCACHE_NONE) {
 536                 ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 537                 if (ret != 0)
 538                         return ret;
 539
 540                 for (i = 0; i < val_count * val_bytes; i += val_bytes)
 541                         map->format.parse_val(val + i);
 542         } else {
 543                 for (i = 0; i < val_count; i++) {
 544                         ret = regmap_read(map, reg + i, val + (i * val_bytes));
 545                         if (ret != 0)
 546                                 return ret;
 547                 }
 548         }
 549
 550         return 0;
 551 }
 552 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 553
 554 /**
 555  * regmap_update_bits: Perform a read/modify/write cycle on the register map
 556  *
 557  * @map: Register map to update
 558  * @reg: Register to update
 559  * @mask: Bitmask to change
 560  * @val: New value for bitmask
 561  *
 562  * Returns zero for success, a negative number on error.
 563  */
 564 int regmap_update_bits(struct regmap *map, unsigned int reg,
 565                        unsigned int mask, unsigned int val)
 566 {
 567         int ret;
 568         unsigned int tmp;
 569
 570         mutex_lock(&map->lock);
 571
 572         ret = _regmap_read(map, reg, &tmp);
 573         if (ret != 0)
 574                 goto out;
 575
 576         tmp &= ~mask;
 577         tmp |= val & mask;
 578
 579         ret = _regmap_write(map, reg, tmp);
 580
 581 out:
 582         mutex_unlock(&map->lock);
 583
 584         return ret;
 585 }
 586 EXPORT_SYMBOL_GPL(regmap_update_bits);
 587
 588 static int __init regmap_initcall(void)
 589 {
 590         regmap_debugfs_initcall();
 591
 592         return 0;
 593 }
 594 postcore_initcall(regmap_initcall);