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_10_14_write(struct regmap *map,
  94                                     unsigned int reg, unsigned int val)
  95 {
  96         u8 *out = map->work_buf;
  97
  98         out[2] = val;
  99         out[1] = (val >> 8) | (reg << 6);
 100         out[0] = reg >> 2;
 101 }
 102
 103 static void regmap_format_8(void *buf, unsigned int val)
 104 {
 105         u8 *b = buf;
 106
 107         b[0] = val;
 108 }
 109
 110 static void regmap_format_16(void *buf, unsigned int val)
 111 {
 112         __be16 *b = buf;
 113
 114         b[0] = cpu_to_be16(val);
 115 }
 116
 117 static unsigned int regmap_parse_8(void *buf)
 118 {
 119         u8 *b = buf;
 120
 121         return b[0];
 122 }
 123
 124 static unsigned int regmap_parse_16(void *buf)
 125 {
 126         __be16 *b = buf;
 127
 128         b[0] = be16_to_cpu(b[0]);
 129
 130         return b[0];
 131 }
 132
 133 /**
 134  * regmap_init(): Initialise register map
 135  *
 136  * @dev: Device that will be interacted with
 137  * @bus: Bus-specific callbacks to use with device
 138  * @config: Configuration for register map
 139  *
 140  * The return value will be an ERR_PTR() on error or a valid pointer to
 141  * a struct regmap.  This function should generally not be called
 142  * directly, it should be called by bus-specific init functions.
 143  */
 144 struct regmap *regmap_init(struct device *dev,
 145                            const struct regmap_bus *bus,
 146                            const struct regmap_config *config)
 147 {
 148         struct regmap *map;
 149         int ret = -EINVAL;
 150
 151         if (!bus || !config)
 152                 goto err;
 153
 154         map = kzalloc(sizeof(*map), GFP_KERNEL);
 155         if (map == NULL) {
 156                 ret = -ENOMEM;
 157                 goto err;
 158         }
 159
 160         mutex_init(&map->lock);
 161         map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
 162         map->format.reg_bytes = config->reg_bits / 8;
 163         map->format.val_bytes = config->val_bits / 8;
 164         map->dev = dev;
 165         map->bus = bus;
 166         map->max_register = config->max_register;
 167         map->writeable_reg = config->writeable_reg;
 168         map->readable_reg = config->readable_reg;
 169         map->volatile_reg = config->volatile_reg;
 170         map->precious_reg = config->precious_reg;
 171         map->cache_type = config->cache_type;
 172
 173         if (config->read_flag_mask || config->write_flag_mask) {
 174                 map->read_flag_mask = config->read_flag_mask;
 175                 map->write_flag_mask = config->write_flag_mask;
 176         } else {
 177                 map->read_flag_mask = bus->read_flag_mask;
 178         }
 179
 180         switch (config->reg_bits) {
 181         case 4:
 182                 switch (config->val_bits) {
 183                 case 12:
 184                         map->format.format_write = regmap_format_4_12_write;
 185                         break;
 186                 default:
 187                         goto err_map;
 188                 }
 189                 break;
 190
 191         case 7:
 192                 switch (config->val_bits) {
 193                 case 9:
 194                         map->format.format_write = regmap_format_7_9_write;
 195                         break;
 196                 default:
 197                         goto err_map;
 198                 }
 199                 break;
 200
 201         case 10:
 202                 switch (config->val_bits) {
 203                 case 14:
 204                         map->format.format_write = regmap_format_10_14_write;
 205                         break;
 206                 default:
 207                         goto err_map;
 208                 }
 209                 break;
 210
 211         case 8:
 212                 map->format.format_reg = regmap_format_8;
 213                 break;
 214
 215         case 16:
 216                 map->format.format_reg = regmap_format_16;
 217                 break;
 218
 219         default:
 220                 goto err_map;
 221         }
 222
 223         switch (config->val_bits) {
 224         case 8:
 225                 map->format.format_val = regmap_format_8;
 226                 map->format.parse_val = regmap_parse_8;
 227                 break;
 228         case 16:
 229                 map->format.format_val = regmap_format_16;
 230                 map->format.parse_val = regmap_parse_16;
 231                 break;
 232         }
 233
 234         if (!map->format.format_write &&
 235             !(map->format.format_reg && map->format.format_val))
 236                 goto err_map;
 237
 238         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 239         if (map->work_buf == NULL) {
 240                 ret = -ENOMEM;
 241                 goto err_map;
 242         }
 243
 244         regmap_debugfs_init(map);
 245
 246         ret = regcache_init(map, config);
 247         if (ret < 0)
 248                 goto err_free_workbuf;
 249
 250         return map;
 251
 252 err_free_workbuf:
 253         kfree(map->work_buf);
 254 err_map:
 255         kfree(map);
 256 err:
 257         return ERR_PTR(ret);
 258 }
 259 EXPORT_SYMBOL_GPL(regmap_init);
 260
 261 /**
 262  * regmap_reinit_cache(): Reinitialise the current register cache
 263  *
 264  * @map: Register map to operate on.
 265  * @config: New configuration.  Only the cache data will be used.
 266  *
 267  * Discard any existing register cache for the map and initialize a
 268  * new cache.  This can be used to restore the cache to defaults or to
 269  * update the cache configuration to reflect runtime discovery of the
 270  * hardware.
 271  */
 272 int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
 273 {
 274         int ret;
 275
 276         mutex_lock(&map->lock);
 277
 278         regcache_exit(map);
 279
 280         map->max_register = config->max_register;
 281         map->writeable_reg = config->writeable_reg;
 282         map->readable_reg = config->readable_reg;
 283         map->volatile_reg = config->volatile_reg;
 284         map->precious_reg = config->precious_reg;
 285         map->cache_type = config->cache_type;
 286
 287         map->cache_bypass = false;
 288         map->cache_only = false;
 289
 290         ret = regcache_init(map, config);
 291
 292         mutex_unlock(&map->lock);
 293
 294         return ret;
 295 }
 296
 297 /**
 298  * regmap_exit(): Free a previously allocated register map
 299  */
 300 void regmap_exit(struct regmap *map)
 301 {
 302         regcache_exit(map);
 303         regmap_debugfs_exit(map);
 304         kfree(map->work_buf);
 305         kfree(map);
 306 }
 307 EXPORT_SYMBOL_GPL(regmap_exit);
 308
 309 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 310                              const void *val, size_t val_len)
 311 {
 312         u8 *u8 = map->work_buf;
 313         void *buf;
 314         int ret = -ENOTSUPP;
 315         size_t len;
 316         int i;
 317
 318         /* Check for unwritable registers before we start */
 319         if (map->writeable_reg)
 320                 for (i = 0; i < val_len / map->format.val_bytes; i++)
 321                         if (!map->writeable_reg(map->dev, reg + i))
 322                                 return -EINVAL;
 323
 324         map->format.format_reg(map->work_buf, reg);
 325
 326         u8[0] |= map->write_flag_mask;
 327
 328         trace_regmap_hw_write_start(map->dev, reg,
 329                                     val_len / map->format.val_bytes);
 330
 331         /* If we're doing a single register write we can probably just
 332          * send the work_buf directly, otherwise try to do a gather
 333          * write.
 334          */
 335         if (val == map->work_buf + map->format.reg_bytes)
 336                 ret = map->bus->write(map->dev, map->work_buf,
 337                                       map->format.reg_bytes + val_len);
 338         else if (map->bus->gather_write)
 339                 ret = map->bus->gather_write(map->dev, map->work_buf,
 340                                              map->format.reg_bytes,
 341                                              val, val_len);
 342
 343         /* If that didn't work fall back on linearising by hand. */
 344         if (ret == -ENOTSUPP) {
 345                 len = map->format.reg_bytes + val_len;
 346                 buf = kmalloc(len, GFP_KERNEL);
 347                 if (!buf)
 348                         return -ENOMEM;
 349
 350                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 351                 memcpy(buf + map->format.reg_bytes, val, val_len);
 352                 ret = map->bus->write(map->dev, buf, len);
 353
 354                 kfree(buf);
 355         }
 356
 357         trace_regmap_hw_write_done(map->dev, reg,
 358                                    val_len / map->format.val_bytes);
 359
 360         return ret;
 361 }
 362
 363 int _regmap_write(struct regmap *map, unsigned int reg,
 364                   unsigned int val)
 365 {
 366         int ret;
 367         BUG_ON(!map->format.format_write && !map->format.format_val);
 368
 369         if (!map->cache_bypass) {
 370                 ret = regcache_write(map, reg, val);
 371                 if (ret != 0)
 372                         return ret;
 373                 if (map->cache_only) {
 374                         map->cache_dirty = true;
 375                         return 0;
 376                 }
 377         }
 378
 379         trace_regmap_reg_write(map->dev, reg, val);
 380
 381         if (map->format.format_write) {
 382                 map->format.format_write(map, reg, val);
 383
 384                 trace_regmap_hw_write_start(map->dev, reg, 1);
 385
 386                 ret = map->bus->write(map->dev, map->work_buf,
 387                                       map->format.buf_size);
 388
 389                 trace_regmap_hw_write_done(map->dev, reg, 1);
 390
 391                 return ret;
 392         } else {
 393                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 394                                        val);
 395                 return _regmap_raw_write(map, reg,
 396                                          map->work_buf + map->format.reg_bytes,
 397                                          map->format.val_bytes);
 398         }
 399 }
 400
 401 /**
 402  * regmap_write(): Write a value to a single register
 403  *
 404  * @map: Register map to write to
 405  * @reg: Register to write to
 406  * @val: Value to be written
 407  *
 408  * A value of zero will be returned on success, a negative errno will
 409  * be returned in error cases.
 410  */
 411 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 412 {
 413         int ret;
 414
 415         mutex_lock(&map->lock);
 416
 417         ret = _regmap_write(map, reg, val);
 418
 419         mutex_unlock(&map->lock);
 420
 421         return ret;
 422 }
 423 EXPORT_SYMBOL_GPL(regmap_write);
 424
 425 /**
 426  * regmap_raw_write(): Write raw values to one or more registers
 427  *
 428  * @map: Register map to write to
 429  * @reg: Initial register to write to
 430  * @val: Block of data to be written, laid out for direct transmission to the
 431  *       device
 432  * @val_len: Length of data pointed to by val.
 433  *
 434  * This function is intended to be used for things like firmware
 435  * download where a large block of data needs to be transferred to the
 436  * device.  No formatting will be done on the data provided.
 437  *
 438  * A value of zero will be returned on success, a negative errno will
 439  * be returned in error cases.
 440  */
 441 int regmap_raw_write(struct regmap *map, unsigned int reg,
 442                      const void *val, size_t val_len)
 443 {
 444         size_t val_count = val_len / map->format.val_bytes;
 445         int ret;
 446
 447         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 448                 map->cache_type != REGCACHE_NONE);
 449
 450         mutex_lock(&map->lock);
 451
 452         ret = _regmap_raw_write(map, reg, val, val_len);
 453
 454         mutex_unlock(&map->lock);
 455
 456         return ret;
 457 }
 458 EXPORT_SYMBOL_GPL(regmap_raw_write);
 459
 460 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 461                             unsigned int val_len)
 462 {
 463         u8 *u8 = map->work_buf;
 464         int ret;
 465
 466         map->format.format_reg(map->work_buf, reg);
 467
 468         /*
 469          * Some buses or devices flag reads by setting the high bits in the
 470          * register addresss; since it's always the high bits for all
 471          * current formats we can do this here rather than in
 472          * formatting.  This may break if we get interesting formats.
 473          */
 474         u8[0] |= map->read_flag_mask;
 475
 476         trace_regmap_hw_read_start(map->dev, reg,
 477                                    val_len / map->format.val_bytes);
 478
 479         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 480                              val, val_len);
 481
 482         trace_regmap_hw_read_done(map->dev, reg,
 483                                   val_len / map->format.val_bytes);
 484
 485         return ret;
 486 }
 487
 488 static int _regmap_read(struct regmap *map, unsigned int reg,
 489                         unsigned int *val)
 490 {
 491         int ret;
 492
 493         if (!map->cache_bypass) {
 494                 ret = regcache_read(map, reg, val);
 495                 if (ret == 0)
 496                         return 0;
 497         }
 498
 499         if (!map->format.parse_val)
 500                 return -EINVAL;
 501
 502         if (map->cache_only)
 503                 return -EBUSY;
 504
 505         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 506         if (ret == 0) {
 507                 *val = map->format.parse_val(map->work_buf);
 508                 trace_regmap_reg_read(map->dev, reg, *val);
 509         }
 510
 511         return ret;
 512 }
 513
 514 /**
 515  * regmap_read(): Read a value from a single register
 516  *
 517  * @map: Register map to write to
 518  * @reg: Register to be read from
 519  * @val: Pointer to store read value
 520  *
 521  * A value of zero will be returned on success, a negative errno will
 522  * be returned in error cases.
 523  */
 524 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 525 {
 526         int ret;
 527
 528         mutex_lock(&map->lock);
 529
 530         ret = _regmap_read(map, reg, val);
 531
 532         mutex_unlock(&map->lock);
 533
 534         return ret;
 535 }
 536 EXPORT_SYMBOL_GPL(regmap_read);
 537
 538 /**
 539  * regmap_raw_read(): Read raw data from the device
 540  *
 541  * @map: Register map to write to
 542  * @reg: First register to be read from
 543  * @val: Pointer to store read value
 544  * @val_len: Size of data to read
 545  *
 546  * A value of zero will be returned on success, a negative errno will
 547  * be returned in error cases.
 548  */
 549 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 550                     size_t val_len)
 551 {
 552         size_t val_count = val_len / map->format.val_bytes;
 553         int ret;
 554
 555         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 556                 map->cache_type != REGCACHE_NONE);
 557
 558         mutex_lock(&map->lock);
 559
 560         ret = _regmap_raw_read(map, reg, val, val_len);
 561
 562         mutex_unlock(&map->lock);
 563
 564         return ret;
 565 }
 566 EXPORT_SYMBOL_GPL(regmap_raw_read);
 567
 568 /**
 569  * regmap_bulk_read(): Read multiple registers from the device
 570  *
 571  * @map: Register map to write to
 572  * @reg: First register to be read from
 573  * @val: Pointer to store read value, in native register size for device
 574  * @val_count: Number of registers to read
 575  *
 576  * A value of zero will be returned on success, a negative errno will
 577  * be returned in error cases.
 578  */
 579 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 580                      size_t val_count)
 581 {
 582         int ret, i;
 583         size_t val_bytes = map->format.val_bytes;
 584         bool vol = regmap_volatile_range(map, reg, val_count);
 585
 586         if (!map->format.parse_val)
 587                 return -EINVAL;
 588
 589         if (vol || map->cache_type == REGCACHE_NONE) {
 590                 ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 591                 if (ret != 0)
 592                         return ret;
 593
 594                 for (i = 0; i < val_count * val_bytes; i += val_bytes)
 595                         map->format.parse_val(val + i);
 596         } else {
 597                 for (i = 0; i < val_count; i++) {
 598                         ret = regmap_read(map, reg + i, val + (i * val_bytes));
 599                         if (ret != 0)
 600                                 return ret;
 601                 }
 602         }
 603
 604         return 0;
 605 }
 606 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 607
 608 static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 609                                unsigned int mask, unsigned int val,
 610                                bool *change)
 611 {
 612         int ret;
 613         unsigned int tmp, orig;
 614
 615         mutex_lock(&map->lock);
 616
 617         ret = _regmap_read(map, reg, &orig);
 618         if (ret != 0)
 619                 goto out;
 620
 621         tmp = orig & ~mask;
 622         tmp |= val & mask;
 623
 624         if (tmp != orig) {
 625                 ret = _regmap_write(map, reg, tmp);
 626                 *change = true;
 627         } else {
 628                 *change = false;
 629         }
 630
 631 out:
 632         mutex_unlock(&map->lock);
 633
 634         return ret;
 635 }
 636
 637 /**
 638  * regmap_update_bits: Perform a read/modify/write cycle on the register map
 639  *
 640  * @map: Register map to update
 641  * @reg: Register to update
 642  * @mask: Bitmask to change
 643  * @val: New value for bitmask
 644  *
 645  * Returns zero for success, a negative number on error.
 646  */
 647 int regmap_update_bits(struct regmap *map, unsigned int reg,
 648                        unsigned int mask, unsigned int val)
 649 {
 650         bool change;
 651         return _regmap_update_bits(map, reg, mask, val, &change);
 652 }
 653 EXPORT_SYMBOL_GPL(regmap_update_bits);
 654
 655 /**
 656  * regmap_update_bits_check: Perform a read/modify/write cycle on the
 657  *                           register map and report if updated
 658  *
 659  * @map: Register map to update
 660  * @reg: Register to update
 661  * @mask: Bitmask to change
 662  * @val: New value for bitmask
 663  * @change: Boolean indicating if a write was done
 664  *
 665  * Returns zero for success, a negative number on error.
 666  */
 667 int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 668                              unsigned int mask, unsigned int val,
 669                              bool *change)
 670 {
 671         return _regmap_update_bits(map, reg, mask, val, change);
 672 }
 673 EXPORT_SYMBOL_GPL(regmap_update_bits_check);
 674
 675 static int __init regmap_initcall(void)
 676 {
 677         regmap_debugfs_initcall();
 678
 679         return 0;
 680 }
 681 postcore_initcall(regmap_initcall);