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