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                 goto err;
 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
 163         if (config->read_flag_mask || config->write_flag_mask) {
 164                 map->read_flag_mask = config->read_flag_mask;
 165                 map->write_flag_mask = config->write_flag_mask;
 166         } else {
 167                 map->read_flag_mask = bus->read_flag_mask;
 168         }
 169
 170         switch (config->reg_bits) {
 171         case 4:
 172                 switch (config->val_bits) {
 173                 case 12:
 174                         map->format.format_write = regmap_format_4_12_write;
 175                         break;
 176                 default:
 177                         goto err_map;
 178                 }
 179                 break;
 180
 181         case 7:
 182                 switch (config->val_bits) {
 183                 case 9:
 184                         map->format.format_write = regmap_format_7_9_write;
 185                         break;
 186                 default:
 187                         goto err_map;
 188                 }
 189                 break;
 190
 191         case 8:
 192                 map->format.format_reg = regmap_format_8;
 193                 break;
 194
 195         case 16:
 196                 map->format.format_reg = regmap_format_16;
 197                 break;
 198
 199         default:
 200                 goto err_map;
 201         }
 202
 203         switch (config->val_bits) {
 204         case 8:
 205                 map->format.format_val = regmap_format_8;
 206                 map->format.parse_val = regmap_parse_8;
 207                 break;
 208         case 16:
 209                 map->format.format_val = regmap_format_16;
 210                 map->format.parse_val = regmap_parse_16;
 211                 break;
 212         }
 213
 214         if (!map->format.format_write &&
 215             !(map->format.format_reg && map->format.format_val))
 216                 goto err_map;
 217
 218         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 219         if (map->work_buf == NULL) {
 220                 ret = -ENOMEM;
 221                 goto err_map;
 222         }
 223
 224         ret = regcache_init(map, config);
 225         if (ret < 0)
 226                 goto err_free_workbuf;
 227
 228         regmap_debugfs_init(map);
 229
 230         return map;
 231
 232 err_free_workbuf:
 233         kfree(map->work_buf);
 234 err_map:
 235         kfree(map);
 236 err:
 237         return ERR_PTR(ret);
 238 }
 239 EXPORT_SYMBOL_GPL(regmap_init);
 240
 241 /**
 242  * regmap_exit(): Free a previously allocated register map
 243  */
 244 void regmap_exit(struct regmap *map)
 245 {
 246         regcache_exit(map);
 247         regmap_debugfs_exit(map);
 248         kfree(map->work_buf);
 249         kfree(map);
 250 }
 251 EXPORT_SYMBOL_GPL(regmap_exit);
 252
 253 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 254                              const void *val, size_t val_len)
 255 {
 256         u8 *u8 = map->work_buf;
 257         void *buf;
 258         int ret = -ENOTSUPP;
 259         size_t len;
 260         int i;
 261
 262         /* Check for unwritable registers before we start */
 263         if (map->writeable_reg)
 264                 for (i = 0; i < val_len / map->format.val_bytes; i++)
 265                         if (!map->writeable_reg(map->dev, reg + i))
 266                                 return -EINVAL;
 267
 268         map->format.format_reg(map->work_buf, reg);
 269
 270         u8[0] |= map->write_flag_mask;
 271
 272         trace_regmap_hw_write_start(map->dev, reg,
 273                                     val_len / map->format.val_bytes);
 274
 275         /* If we're doing a single register write we can probably just
 276          * send the work_buf directly, otherwise try to do a gather
 277          * write.
 278          */
 279         if (val == map->work_buf + map->format.reg_bytes)
 280                 ret = map->bus->write(map->dev, map->work_buf,
 281                                       map->format.reg_bytes + val_len);
 282         else if (map->bus->gather_write)
 283                 ret = map->bus->gather_write(map->dev, map->work_buf,
 284                                              map->format.reg_bytes,
 285                                              val, val_len);
 286
 287         /* If that didn't work fall back on linearising by hand. */
 288         if (ret == -ENOTSUPP) {
 289                 len = map->format.reg_bytes + val_len;
 290                 buf = kmalloc(len, GFP_KERNEL);
 291                 if (!buf)
 292                         return -ENOMEM;
 293
 294                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 295                 memcpy(buf + map->format.reg_bytes, val, val_len);
 296                 ret = map->bus->write(map->dev, buf, len);
 297
 298                 kfree(buf);
 299         }
 300
 301         trace_regmap_hw_write_done(map->dev, reg,
 302                                    val_len / map->format.val_bytes);
 303
 304         return ret;
 305 }
 306
 307 int _regmap_write(struct regmap *map, unsigned int reg,
 308                   unsigned int val)
 309 {
 310         int ret;
 311         BUG_ON(!map->format.format_write && !map->format.format_val);
 312
 313         if (!map->cache_bypass) {
 314                 ret = regcache_write(map, reg, val);
 315                 if (ret != 0)
 316                         return ret;
 317                 if (map->cache_only) {
 318                         map->cache_dirty = true;
 319                         return 0;
 320                 }
 321         }
 322
 323         trace_regmap_reg_write(map->dev, reg, val);
 324
 325         if (map->format.format_write) {
 326                 map->format.format_write(map, reg, val);
 327
 328                 trace_regmap_hw_write_start(map->dev, reg, 1);
 329
 330                 ret = map->bus->write(map->dev, map->work_buf,
 331                                       map->format.buf_size);
 332
 333                 trace_regmap_hw_write_done(map->dev, reg, 1);
 334
 335                 return ret;
 336         } else {
 337                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 338                                        val);
 339                 return _regmap_raw_write(map, reg,
 340                                          map->work_buf + map->format.reg_bytes,
 341                                          map->format.val_bytes);
 342         }
 343 }
 344
 345 /**
 346  * regmap_write(): Write a value to a single register
 347  *
 348  * @map: Register map to write to
 349  * @reg: Register to write to
 350  * @val: Value to be written
 351  *
 352  * A value of zero will be returned on success, a negative errno will
 353  * be returned in error cases.
 354  */
 355 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 356 {
 357         int ret;
 358
 359         mutex_lock(&map->lock);
 360
 361         ret = _regmap_write(map, reg, val);
 362
 363         mutex_unlock(&map->lock);
 364
 365         return ret;
 366 }
 367 EXPORT_SYMBOL_GPL(regmap_write);
 368
 369 /**
 370  * regmap_raw_write(): Write raw values to one or more registers
 371  *
 372  * @map: Register map to write to
 373  * @reg: Initial register to write to
 374  * @val: Block of data to be written, laid out for direct transmission to the
 375  *       device
 376  * @val_len: Length of data pointed to by val.
 377  *
 378  * This function is intended to be used for things like firmware
 379  * download where a large block of data needs to be transferred to the
 380  * device.  No formatting will be done on the data provided.
 381  *
 382  * A value of zero will be returned on success, a negative errno will
 383  * be returned in error cases.
 384  */
 385 int regmap_raw_write(struct regmap *map, unsigned int reg,
 386                      const void *val, size_t val_len)
 387 {
 388         size_t val_count = val_len / map->format.val_bytes;
 389         int ret;
 390
 391         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 392                 map->cache_type != REGCACHE_NONE);
 393
 394         mutex_lock(&map->lock);
 395
 396         ret = _regmap_raw_write(map, reg, val, val_len);
 397
 398         mutex_unlock(&map->lock);
 399
 400         return ret;
 401 }
 402 EXPORT_SYMBOL_GPL(regmap_raw_write);
 403
 404 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 405                             unsigned int val_len)
 406 {
 407         u8 *u8 = map->work_buf;
 408         int ret;
 409
 410         map->format.format_reg(map->work_buf, reg);
 411
 412         /*
 413          * Some buses or devices flag reads by setting the high bits in the
 414          * register addresss; since it's always the high bits for all
 415          * current formats we can do this here rather than in
 416          * formatting.  This may break if we get interesting formats.
 417          */
 418         u8[0] |= map->read_flag_mask;
 419
 420         trace_regmap_hw_read_start(map->dev, reg,
 421                                    val_len / map->format.val_bytes);
 422
 423         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 424                              val, val_len);
 425
 426         trace_regmap_hw_read_done(map->dev, reg,
 427                                   val_len / map->format.val_bytes);
 428
 429         return ret;
 430 }
 431
 432 static int _regmap_read(struct regmap *map, unsigned int reg,
 433                         unsigned int *val)
 434 {
 435         int ret;
 436
 437         if (!map->format.parse_val)
 438                 return -EINVAL;
 439
 440         if (!map->cache_bypass) {
 441                 ret = regcache_read(map, reg, val);
 442                 if (ret == 0)
 443                         return 0;
 444         }
 445
 446         if (map->cache_only)
 447                 return -EBUSY;
 448
 449         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 450         if (ret == 0) {
 451                 *val = map->format.parse_val(map->work_buf);
 452                 trace_regmap_reg_read(map->dev, reg, *val);
 453         }
 454
 455         return ret;
 456 }
 457
 458 /**
 459  * regmap_read(): Read a value from a single register
 460  *
 461  * @map: Register map to write to
 462  * @reg: Register to be read from
 463  * @val: Pointer to store read value
 464  *
 465  * A value of zero will be returned on success, a negative errno will
 466  * be returned in error cases.
 467  */
 468 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 469 {
 470         int ret;
 471
 472         mutex_lock(&map->lock);
 473
 474         ret = _regmap_read(map, reg, val);
 475
 476         mutex_unlock(&map->lock);
 477
 478         return ret;
 479 }
 480 EXPORT_SYMBOL_GPL(regmap_read);
 481
 482 /**
 483  * regmap_raw_read(): Read raw data from the device
 484  *
 485  * @map: Register map to write to
 486  * @reg: First register to be read from
 487  * @val: Pointer to store read value
 488  * @val_len: Size of data to read
 489  *
 490  * A value of zero will be returned on success, a negative errno will
 491  * be returned in error cases.
 492  */
 493 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 494                     size_t val_len)
 495 {
 496         size_t val_count = val_len / map->format.val_bytes;
 497         int ret;
 498
 499         WARN_ON(!regmap_volatile_range(map, reg, val_count) &&
 500                 map->cache_type != REGCACHE_NONE);
 501
 502         mutex_lock(&map->lock);
 503
 504         ret = _regmap_raw_read(map, reg, val, val_len);
 505
 506         mutex_unlock(&map->lock);
 507
 508         return ret;
 509 }
 510 EXPORT_SYMBOL_GPL(regmap_raw_read);
 511
 512 /**
 513  * regmap_bulk_read(): Read multiple registers from the device
 514  *
 515  * @map: Register map to write to
 516  * @reg: First register to be read from
 517  * @val: Pointer to store read value, in native register size for device
 518  * @val_count: Number of registers to read
 519  *
 520  * A value of zero will be returned on success, a negative errno will
 521  * be returned in error cases.
 522  */
 523 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 524                      size_t val_count)
 525 {
 526         int ret, i;
 527         size_t val_bytes = map->format.val_bytes;
 528         bool vol = regmap_volatile_range(map, reg, val_count);
 529
 530         if (!map->format.parse_val)
 531                 return -EINVAL;
 532
 533         if (vol || map->cache_type == REGCACHE_NONE) {
 534                 ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 535                 if (ret != 0)
 536                         return ret;
 537
 538                 for (i = 0; i < val_count * val_bytes; i += val_bytes)
 539                         map->format.parse_val(val + i);
 540         } else {
 541                 for (i = 0; i < val_count; i++) {
 542                         ret = regmap_read(map, reg + i, val + (i * val_bytes));
 543                         if (ret != 0)
 544                                 return ret;
 545                 }
 546         }
 547
 548         return 0;
 549 }
 550 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 551
 552 /**
 553  * regmap_update_bits: Perform a read/modify/write cycle on the register map
 554  *
 555  * @map: Register map to update
 556  * @reg: Register to update
 557  * @mask: Bitmask to change
 558  * @val: New value for bitmask
 559  *
 560  * Returns zero for success, a negative number on error.
 561  */
 562 int regmap_update_bits(struct regmap *map, unsigned int reg,
 563                        unsigned int mask, unsigned int val)
 564 {
 565         int ret;
 566         unsigned int tmp;
 567
 568         mutex_lock(&map->lock);
 569
 570         ret = _regmap_read(map, reg, &tmp);
 571         if (ret != 0)
 572                 goto out;
 573
 574         tmp &= ~mask;
 575         tmp |= val & mask;
 576
 577         ret = _regmap_write(map, reg, tmp);
 578
 579 out:
 580         mutex_unlock(&map->lock);
 581
 582         return ret;
 583 }
 584 EXPORT_SYMBOL_GPL(regmap_update_bits);
 585
 586 static int __init regmap_initcall(void)
 587 {
 588         regmap_debugfs_initcall();
 589
 590         return 0;
 591 }
 592 postcore_initcall(regmap_initcall);