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 static void devm_regmap_release(struct device *dev, void *res)
 262 {
 263         regmap_exit(*(struct regmap **)res);
 264 }
 265
 266 /**
 267  * devm_regmap_init(): Initialise managed register map
 268  *
 269  * @dev: Device that will be interacted with
 270  * @bus: Bus-specific callbacks to use with device
 271  * @config: Configuration for register map
 272  *
 273  * The return value will be an ERR_PTR() on error or a valid pointer
 274  * to a struct regmap.  This function should generally not be called
 275  * directly, it should be called by bus-specific init functions.  The
 276  * map will be automatically freed by the device management code.
 277  */
 278 struct regmap *devm_regmap_init(struct device *dev,
 279                                 const struct regmap_bus *bus,
 280                                 const struct regmap_config *config)
 281 {
 282         struct regmap **ptr, *regmap;
 283
 284         ptr = devres_alloc(devm_regmap_release, sizeof(*ptr), GFP_KERNEL);
 285         if (!ptr)
 286                 return ERR_PTR(-ENOMEM);
 287
 288         regmap = regmap_init(dev, bus, config);
 289         if (!IS_ERR(regmap)) {
 290                 *ptr = regmap;
 291                 devres_add(dev, ptr);
 292         } else {
 293                 devres_free(ptr);
 294         }
 295
 296         return regmap;
 297 }
 298 EXPORT_SYMBOL_GPL(devm_regmap_init);
 299
 300 /**
 301  * regmap_reinit_cache(): Reinitialise the current register cache
 302  *
 303  * @map: Register map to operate on.
 304  * @config: New configuration.  Only the cache data will be used.
 305  *
 306  * Discard any existing register cache for the map and initialize a
 307  * new cache.  This can be used to restore the cache to defaults or to
 308  * update the cache configuration to reflect runtime discovery of the
 309  * hardware.
 310  */
 311 int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
 312 {
 313         int ret;
 314
 315         mutex_lock(&map->lock);
 316
 317         regcache_exit(map);
 318
 319         map->max_register = config->max_register;
 320         map->writeable_reg = config->writeable_reg;
 321         map->readable_reg = config->readable_reg;
 322         map->volatile_reg = config->volatile_reg;
 323         map->precious_reg = config->precious_reg;
 324         map->cache_type = config->cache_type;
 325
 326         map->cache_bypass = false;
 327         map->cache_only = false;
 328
 329         ret = regcache_init(map, config);
 330
 331         mutex_unlock(&map->lock);
 332
 333         return ret;
 334 }
 335
 336 /**
 337  * regmap_exit(): Free a previously allocated register map
 338  */
 339 void regmap_exit(struct regmap *map)
 340 {
 341         regcache_exit(map);
 342         regmap_debugfs_exit(map);
 343         kfree(map->work_buf);
 344         kfree(map);
 345 }
 346 EXPORT_SYMBOL_GPL(regmap_exit);
 347
 348 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 349                              const void *val, size_t val_len)
 350 {
 351         u8 *u8 = map->work_buf;
 352         void *buf;
 353         int ret = -ENOTSUPP;
 354         size_t len;
 355         int i;
 356
 357         /* Check for unwritable registers before we start */
 358         if (map->writeable_reg)
 359                 for (i = 0; i < val_len / map->format.val_bytes; i++)
 360                         if (!map->writeable_reg(map->dev, reg + i))
 361                                 return -EINVAL;
 362
 363         map->format.format_reg(map->work_buf, reg);
 364
 365         u8[0] |= map->write_flag_mask;
 366
 367         trace_regmap_hw_write_start(map->dev, reg,
 368                                     val_len / map->format.val_bytes);
 369
 370         /* If we're doing a single register write we can probably just
 371          * send the work_buf directly, otherwise try to do a gather
 372          * write.
 373          */
 374         if (val == map->work_buf + map->format.reg_bytes)
 375                 ret = map->bus->write(map->dev, map->work_buf,
 376                                       map->format.reg_bytes + val_len);
 377         else if (map->bus->gather_write)
 378                 ret = map->bus->gather_write(map->dev, map->work_buf,
 379                                              map->format.reg_bytes,
 380                                              val, val_len);
 381
 382         /* If that didn't work fall back on linearising by hand. */
 383         if (ret == -ENOTSUPP) {
 384                 len = map->format.reg_bytes + val_len;
 385                 buf = kmalloc(len, GFP_KERNEL);
 386                 if (!buf)
 387                         return -ENOMEM;
 388
 389                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 390                 memcpy(buf + map->format.reg_bytes, val, val_len);
 391                 ret = map->bus->write(map->dev, buf, len);
 392
 393                 kfree(buf);
 394         }
 395
 396         trace_regmap_hw_write_done(map->dev, reg,
 397                                    val_len / map->format.val_bytes);
 398
 399         return ret;
 400 }
 401
 402 int _regmap_write(struct regmap *map, unsigned int reg,
 403                   unsigned int val)
 404 {
 405         int ret;
 406         BUG_ON(!map->format.format_write && !map->format.format_val);
 407
 408         if (!map->cache_bypass) {
 409                 ret = regcache_write(map, reg, val);
 410                 if (ret != 0)
 411                         return ret;
 412                 if (map->cache_only) {
 413                         map->cache_dirty = true;
 414                         return 0;
 415                 }
 416         }
 417
 418         trace_regmap_reg_write(map->dev, reg, val);
 419
 420         if (map->format.format_write) {
 421                 map->format.format_write(map, reg, val);
 422
 423                 trace_regmap_hw_write_start(map->dev, reg, 1);
 424
 425                 ret = map->bus->write(map->dev, map->work_buf,
 426                                       map->format.buf_size);
 427
 428                 trace_regmap_hw_write_done(map->dev, reg, 1);
 429
 430                 return ret;
 431         } else {
 432                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 433                                        val);
 434                 return _regmap_raw_write(map, reg,
 435                                          map->work_buf + map->format.reg_bytes,
 436                                          map->format.val_bytes);
 437         }
 438 }
 439
 440 /**
 441  * regmap_write(): Write a value to a single register
 442  *
 443  * @map: Register map to write to
 444  * @reg: Register to write to
 445  * @val: Value to be written
 446  *
 447  * A value of zero will be returned on success, a negative errno will
 448  * be returned in error cases.
 449  */
 450 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 451 {
 452         int ret;
 453
 454         mutex_lock(&map->lock);
 455
 456         ret = _regmap_write(map, reg, val);
 457
 458         mutex_unlock(&map->lock);
 459
 460         return ret;
 461 }
 462 EXPORT_SYMBOL_GPL(regmap_write);
 463
 464 /**
 465  * regmap_raw_write(): Write raw values to one or more registers
 466  *
 467  * @map: Register map to write to
 468  * @reg: Initial register to write to
 469  * @val: Block of data to be written, laid out for direct transmission to the
 470  *       device
 471  * @val_len: Length of data pointed to by val.
 472  *
 473  * This function is intended to be used for things like firmware
 474  * download where a large block of data needs to be transferred to the
 475  * device.  No formatting will be done on the data provided.
 476  *
 477  * A value of zero will be returned on success, a negative errno will
 478  * be returned in error cases.
 479  */
 480 int regmap_raw_write(struct regmap *map, unsigned int reg,
 481                      const void *val, size_t val_len)
 482 {
 483         size_t val_count = val_len / map->format.val_bytes;
 484         int ret;
 485
 486         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 487                 map->cache_type != REGCACHE_NONE);
 488
 489         mutex_lock(&map->lock);
 490
 491         ret = _regmap_raw_write(map, reg, val, val_len);
 492
 493         mutex_unlock(&map->lock);
 494
 495         return ret;
 496 }
 497 EXPORT_SYMBOL_GPL(regmap_raw_write);
 498
 499 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 500                             unsigned int val_len)
 501 {
 502         u8 *u8 = map->work_buf;
 503         int ret;
 504
 505         map->format.format_reg(map->work_buf, reg);
 506
 507         /*
 508          * Some buses or devices flag reads by setting the high bits in the
 509          * register addresss; since it's always the high bits for all
 510          * current formats we can do this here rather than in
 511          * formatting.  This may break if we get interesting formats.
 512          */
 513         u8[0] |= map->read_flag_mask;
 514
 515         trace_regmap_hw_read_start(map->dev, reg,
 516                                    val_len / map->format.val_bytes);
 517
 518         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 519                              val, val_len);
 520
 521         trace_regmap_hw_read_done(map->dev, reg,
 522                                   val_len / map->format.val_bytes);
 523
 524         return ret;
 525 }
 526
 527 static int _regmap_read(struct regmap *map, unsigned int reg,
 528                         unsigned int *val)
 529 {
 530         int ret;
 531
 532         if (!map->cache_bypass) {
 533                 ret = regcache_read(map, reg, val);
 534                 if (ret == 0)
 535                         return 0;
 536         }
 537
 538         if (!map->format.parse_val)
 539                 return -EINVAL;
 540
 541         if (map->cache_only)
 542                 return -EBUSY;
 543
 544         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 545         if (ret == 0) {
 546                 *val = map->format.parse_val(map->work_buf);
 547                 trace_regmap_reg_read(map->dev, reg, *val);
 548         }
 549
 550         return ret;
 551 }
 552
 553 /**
 554  * regmap_read(): Read a value from a single register
 555  *
 556  * @map: Register map to write to
 557  * @reg: Register to be read from
 558  * @val: Pointer to store read value
 559  *
 560  * A value of zero will be returned on success, a negative errno will
 561  * be returned in error cases.
 562  */
 563 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 564 {
 565         int ret;
 566
 567         mutex_lock(&map->lock);
 568
 569         ret = _regmap_read(map, reg, val);
 570
 571         mutex_unlock(&map->lock);
 572
 573         return ret;
 574 }
 575 EXPORT_SYMBOL_GPL(regmap_read);
 576
 577 /**
 578  * regmap_raw_read(): Read raw data from the device
 579  *
 580  * @map: Register map to write to
 581  * @reg: First register to be read from
 582  * @val: Pointer to store read value
 583  * @val_len: Size of data to read
 584  *
 585  * A value of zero will be returned on success, a negative errno will
 586  * be returned in error cases.
 587  */
 588 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 589                     size_t val_len)
 590 {
 591         size_t val_count = val_len / map->format.val_bytes;
 592         int ret;
 593
 594         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 595                 map->cache_type != REGCACHE_NONE);
 596
 597         mutex_lock(&map->lock);
 598
 599         ret = _regmap_raw_read(map, reg, val, val_len);
 600
 601         mutex_unlock(&map->lock);
 602
 603         return ret;
 604 }
 605 EXPORT_SYMBOL_GPL(regmap_raw_read);
 606
 607 /**
 608  * regmap_bulk_read(): Read multiple registers from the device
 609  *
 610  * @map: Register map to write to
 611  * @reg: First register to be read from
 612  * @val: Pointer to store read value, in native register size for device
 613  * @val_count: Number of registers to read
 614  *
 615  * A value of zero will be returned on success, a negative errno will
 616  * be returned in error cases.
 617  */
 618 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 619                      size_t val_count)
 620 {
 621         int ret, i;
 622         size_t val_bytes = map->format.val_bytes;
 623         bool vol = regmap_volatile_range(map, reg, val_count);
 624
 625         if (!map->format.parse_val)
 626                 return -EINVAL;
 627
 628         if (vol || map->cache_type == REGCACHE_NONE) {
 629                 ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 630                 if (ret != 0)
 631                         return ret;
 632
 633                 for (i = 0; i < val_count * val_bytes; i += val_bytes)
 634                         map->format.parse_val(val + i);
 635         } else {
 636                 for (i = 0; i < val_count; i++) {
 637                         ret = regmap_read(map, reg + i, val + (i * val_bytes));
 638                         if (ret != 0)
 639                                 return ret;
 640                 }
 641         }
 642
 643         return 0;
 644 }
 645 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 646
 647 static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 648                                unsigned int mask, unsigned int val,
 649                                bool *change)
 650 {
 651         int ret;
 652         unsigned int tmp, orig;
 653
 654         mutex_lock(&map->lock);
 655
 656         ret = _regmap_read(map, reg, &orig);
 657         if (ret != 0)
 658                 goto out;
 659
 660         tmp = orig & ~mask;
 661         tmp |= val & mask;
 662
 663         if (tmp != orig) {
 664                 ret = _regmap_write(map, reg, tmp);
 665                 *change = true;
 666         } else {
 667                 *change = false;
 668         }
 669
 670 out:
 671         mutex_unlock(&map->lock);
 672
 673         return ret;
 674 }
 675
 676 /**
 677  * regmap_update_bits: Perform a read/modify/write cycle on the register map
 678  *
 679  * @map: Register map to update
 680  * @reg: Register to update
 681  * @mask: Bitmask to change
 682  * @val: New value for bitmask
 683  *
 684  * Returns zero for success, a negative number on error.
 685  */
 686 int regmap_update_bits(struct regmap *map, unsigned int reg,
 687                        unsigned int mask, unsigned int val)
 688 {
 689         bool change;
 690         return _regmap_update_bits(map, reg, mask, val, &change);
 691 }
 692 EXPORT_SYMBOL_GPL(regmap_update_bits);
 693
 694 /**
 695  * regmap_update_bits_check: Perform a read/modify/write cycle on the
 696  *                           register map and report if updated
 697  *
 698  * @map: Register map to update
 699  * @reg: Register to update
 700  * @mask: Bitmask to change
 701  * @val: New value for bitmask
 702  * @change: Boolean indicating if a write was done
 703  *
 704  * Returns zero for success, a negative number on error.
 705  */
 706 int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 707                              unsigned int mask, unsigned int val,
 708                              bool *change)
 709 {
 710         return _regmap_update_bits(map, reg, mask, val, change);
 711 }
 712 EXPORT_SYMBOL_GPL(regmap_update_bits_check);
 713
 714 /**
 715  * regmap_register_patch: Register and apply register updates to be applied
 716  *                        on device initialistion
 717  *
 718  * @map: Register map to apply updates to.
 719  * @regs: Values to update.
 720  * @num_regs: Number of entries in regs.
 721  *
 722  * Register a set of register updates to be applied to the device
 723  * whenever the device registers are synchronised with the cache and
 724  * apply them immediately.  Typically this is used to apply
 725  * corrections to be applied to the device defaults on startup, such
 726  * as the updates some vendors provide to undocumented registers.
 727  */
 728 int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
 729                           int num_regs)
 730 {
 731         int i, ret;
 732         bool bypass;
 733
 734         /* If needed the implementation can be extended to support this */
 735         if (map->patch)
 736                 return -EBUSY;
 737
 738         mutex_lock(&map->lock);
 739
 740         bypass = map->cache_bypass;
 741
 742         map->cache_bypass = true;
 743
 744         /* Write out first; it's useful to apply even if we fail later. */
 745         for (i = 0; i < num_regs; i++) {
 746                 ret = _regmap_write(map, regs[i].reg, regs[i].def);
 747                 if (ret != 0) {
 748                         dev_err(map->dev, "Failed to write %x = %x: %d\n",
 749                                 regs[i].reg, regs[i].def, ret);
 750                         goto out;
 751                 }
 752         }
 753
 754         map->patch = kcalloc(num_regs, sizeof(struct reg_default), GFP_KERNEL);
 755         if (map->patch != NULL) {
 756                 memcpy(map->patch, regs,
 757                        num_regs * sizeof(struct reg_default));
 758                 map->patch_regs = num_regs;
 759         } else {
 760                 ret = -ENOMEM;
 761         }
 762
 763 out:
 764         map->cache_bypass = bypass;
 765
 766         mutex_unlock(&map->lock);
 767
 768         return ret;
 769 }
 770 EXPORT_SYMBOL_GPL(regmap_register_patch);
 771
 772 static int __init regmap_initcall(void)
 773 {
 774         regmap_debugfs_initcall();
 775
 776         return 0;
 777 }
 778 postcore_initcall(regmap_initcall);