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
 150         switch (config->reg_bits) {
 151         case 4:
 152                 switch (config->val_bits) {
 153                 case 12:
 154                         map->format.format_write = regmap_format_4_12_write;
 155                         break;
 156                 default:
 157                         goto err_map;
 158                 }
 159                 break;
 160
 161         case 7:
 162                 switch (config->val_bits) {
 163                 case 9:
 164                         map->format.format_write = regmap_format_7_9_write;
 165                         break;
 166                 default:
 167                         goto err_map;
 168                 }
 169                 break;
 170
 171         case 8:
 172                 map->format.format_reg = regmap_format_8;
 173                 break;
 174
 175         case 16:
 176                 map->format.format_reg = regmap_format_16;
 177                 break;
 178
 179         default:
 180                 goto err_map;
 181         }
 182
 183         switch (config->val_bits) {
 184         case 8:
 185                 map->format.format_val = regmap_format_8;
 186                 map->format.parse_val = regmap_parse_8;
 187                 break;
 188         case 16:
 189                 map->format.format_val = regmap_format_16;
 190                 map->format.parse_val = regmap_parse_16;
 191                 break;
 192         }
 193
 194         if (!map->format.format_write &&
 195             !(map->format.format_reg && map->format.format_val))
 196                 goto err_map;
 197
 198         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 199         if (map->work_buf == NULL) {
 200                 ret = -ENOMEM;
 201                 goto err_bus;
 202         }
 203
 204         regmap_debugfs_init(map);
 205
 206         return map;
 207
 208 err_bus:
 209         module_put(map->bus->owner);
 210 err_map:
 211         kfree(map);
 212 err:
 213         return ERR_PTR(ret);
 214 }
 215 EXPORT_SYMBOL_GPL(regmap_init);
 216
 217 /**
 218  * regmap_exit(): Free a previously allocated register map
 219  */
 220 void regmap_exit(struct regmap *map)
 221 {
 222         regmap_debugfs_exit(map);
 223         kfree(map->work_buf);
 224         module_put(map->bus->owner);
 225         kfree(map);
 226 }
 227 EXPORT_SYMBOL_GPL(regmap_exit);
 228
 229 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 230                              const void *val, size_t val_len)
 231 {
 232         void *buf;
 233         int ret = -ENOTSUPP;
 234         size_t len;
 235         int i;
 236
 237         /* Check for unwritable registers before we start */
 238         if (map->writeable_reg)
 239                 for (i = 0; i < val_len / map->format.val_bytes; i++)
 240                         if (!map->writeable_reg(map->dev, reg + i))
 241                                 return -EINVAL;
 242
 243         map->format.format_reg(map->work_buf, reg);
 244
 245         trace_regmap_hw_write_start(map->dev, reg,
 246                                     val_len / map->format.val_bytes);
 247
 248         /* If we're doing a single register write we can probably just
 249          * send the work_buf directly, otherwise try to do a gather
 250          * write.
 251          */
 252         if (val == map->work_buf + map->format.reg_bytes)
 253                 ret = map->bus->write(map->dev, map->work_buf,
 254                                       map->format.reg_bytes + val_len);
 255         else if (map->bus->gather_write)
 256                 ret = map->bus->gather_write(map->dev, map->work_buf,
 257                                              map->format.reg_bytes,
 258                                              val, val_len);
 259
 260         /* If that didn't work fall back on linearising by hand. */
 261         if (ret == -ENOTSUPP) {
 262                 len = map->format.reg_bytes + val_len;
 263                 buf = kmalloc(len, GFP_KERNEL);
 264                 if (!buf)
 265                         return -ENOMEM;
 266
 267                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 268                 memcpy(buf + map->format.reg_bytes, val, val_len);
 269                 ret = map->bus->write(map->dev, buf, len);
 270
 271                 kfree(buf);
 272         }
 273
 274         trace_regmap_hw_write_done(map->dev, reg,
 275                                    val_len / map->format.val_bytes);
 276
 277         return ret;
 278 }
 279
 280 static int _regmap_write(struct regmap *map, unsigned int reg,
 281                          unsigned int val)
 282 {
 283         int ret;
 284         BUG_ON(!map->format.format_write && !map->format.format_val);
 285
 286         trace_regmap_reg_write(map->dev, reg, val);
 287
 288         if (map->format.format_write) {
 289                 map->format.format_write(map, reg, val);
 290
 291                 trace_regmap_hw_write_start(map->dev, reg, 1);
 292
 293                 ret = map->bus->write(map->dev, map->work_buf,
 294                                       map->format.buf_size);
 295
 296                 trace_regmap_hw_write_done(map->dev, reg, 1);
 297
 298                 return ret;
 299         } else {
 300                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 301                                        val);
 302                 return _regmap_raw_write(map, reg,
 303                                          map->work_buf + map->format.reg_bytes,
 304                                          map->format.val_bytes);
 305         }
 306 }
 307
 308 /**
 309  * regmap_write(): Write a value to a single register
 310  *
 311  * @map: Register map to write to
 312  * @reg: Register to write to
 313  * @val: Value to be written
 314  *
 315  * A value of zero will be returned on success, a negative errno will
 316  * be returned in error cases.
 317  */
 318 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 319 {
 320         int ret;
 321
 322         mutex_lock(&map->lock);
 323
 324         ret = _regmap_write(map, reg, val);
 325
 326         mutex_unlock(&map->lock);
 327
 328         return ret;
 329 }
 330 EXPORT_SYMBOL_GPL(regmap_write);
 331
 332 /**
 333  * regmap_raw_write(): Write raw values to one or more registers
 334  *
 335  * @map: Register map to write to
 336  * @reg: Initial register to write to
 337  * @val: Block of data to be written, laid out for direct transmission to the
 338  *       device
 339  * @val_len: Length of data pointed to by val.
 340  *
 341  * This function is intended to be used for things like firmware
 342  * download where a large block of data needs to be transferred to the
 343  * device.  No formatting will be done on the data provided.
 344  *
 345  * A value of zero will be returned on success, a negative errno will
 346  * be returned in error cases.
 347  */
 348 int regmap_raw_write(struct regmap *map, unsigned int reg,
 349                      const void *val, size_t val_len)
 350 {
 351         int ret;
 352
 353         mutex_lock(&map->lock);
 354
 355         ret = _regmap_raw_write(map, reg, val, val_len);
 356
 357         mutex_unlock(&map->lock);
 358
 359         return ret;
 360 }
 361 EXPORT_SYMBOL_GPL(regmap_raw_write);
 362
 363 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 364                             unsigned int val_len)
 365 {
 366         u8 *u8 = map->work_buf;
 367         int ret;
 368
 369         map->format.format_reg(map->work_buf, reg);
 370
 371         /*
 372          * Some buses flag reads by setting the high bits in the
 373          * register addresss; since it's always the high bits for all
 374          * current formats we can do this here rather than in
 375          * formatting.  This may break if we get interesting formats.
 376          */
 377         if (map->bus->read_flag_mask)
 378                 u8[0] |= map->bus->read_flag_mask;
 379
 380         trace_regmap_hw_read_start(map->dev, reg,
 381                                    val_len / map->format.val_bytes);
 382
 383         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 384                              val, val_len);
 385
 386         trace_regmap_hw_read_done(map->dev, reg,
 387                                   val_len / map->format.val_bytes);
 388
 389         return ret;
 390 }
 391
 392 static int _regmap_read(struct regmap *map, unsigned int reg,
 393                         unsigned int *val)
 394 {
 395         int ret;
 396
 397         if (!map->format.parse_val)
 398                 return -EINVAL;
 399
 400         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 401         if (ret == 0) {
 402                 *val = map->format.parse_val(map->work_buf);
 403                 trace_regmap_reg_read(map->dev, reg, *val);
 404         }
 405
 406         return ret;
 407 }
 408
 409 /**
 410  * regmap_read(): Read a value from a single register
 411  *
 412  * @map: Register map to write to
 413  * @reg: Register to be read from
 414  * @val: Pointer to store read value
 415  *
 416  * A value of zero will be returned on success, a negative errno will
 417  * be returned in error cases.
 418  */
 419 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 420 {
 421         int ret;
 422
 423         mutex_lock(&map->lock);
 424
 425         ret = _regmap_read(map, reg, val);
 426
 427         mutex_unlock(&map->lock);
 428
 429         return ret;
 430 }
 431 EXPORT_SYMBOL_GPL(regmap_read);
 432
 433 /**
 434  * regmap_raw_read(): Read raw data from the device
 435  *
 436  * @map: Register map to write to
 437  * @reg: First register to be read from
 438  * @val: Pointer to store read value
 439  * @val_len: Size of data to read
 440  *
 441  * A value of zero will be returned on success, a negative errno will
 442  * be returned in error cases.
 443  */
 444 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 445                     size_t val_len)
 446 {
 447         int ret;
 448
 449         mutex_lock(&map->lock);
 450
 451         ret = _regmap_raw_read(map, reg, val, val_len);
 452
 453         mutex_unlock(&map->lock);
 454
 455         return ret;
 456 }
 457 EXPORT_SYMBOL_GPL(regmap_raw_read);
 458
 459 /**
 460  * regmap_bulk_read(): Read multiple registers from the device
 461  *
 462  * @map: Register map to write to
 463  * @reg: First register to be read from
 464  * @val: Pointer to store read value, in native register size for device
 465  * @val_count: Number of registers to read
 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_bulk_read(struct regmap *map, unsigned int reg, void *val,
 471                      size_t val_count)
 472 {
 473         int ret, i;
 474         size_t val_bytes = map->format.val_bytes;
 475
 476         if (!map->format.parse_val)
 477                 return -EINVAL;
 478
 479         ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 480         if (ret != 0)
 481                 return ret;
 482
 483         for (i = 0; i < val_count * val_bytes; i += val_bytes)
 484                 map->format.parse_val(val + i);
 485
 486         return 0;
 487 }
 488 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 489
 490 /**
 491  * remap_update_bits: Perform a read/modify/write cycle on the register map
 492  *
 493  * @map: Register map to update
 494  * @reg: Register to update
 495  * @mask: Bitmask to change
 496  * @val: New value for bitmask
 497  *
 498  * Returns zero for success, a negative number on error.
 499  */
 500 int regmap_update_bits(struct regmap *map, unsigned int reg,
 501                        unsigned int mask, unsigned int val)
 502 {
 503         int ret;
 504         unsigned int tmp;
 505
 506         mutex_lock(&map->lock);
 507
 508         ret = _regmap_read(map, reg, &tmp);
 509         if (ret != 0)
 510                 goto out;
 511
 512         tmp &= ~mask;
 513         tmp |= val & mask;
 514
 515         ret = _regmap_write(map, reg, tmp);
 516
 517 out:
 518         mutex_unlock(&map->lock);
 519
 520         return ret;
 521 }
 522 EXPORT_SYMBOL_GPL(regmap_update_bits);
 523
 524 static int __init regmap_initcall(void)
 525 {
 526         regmap_debugfs_initcall();
 527
 528         return 0;
 529 }
 530 postcore_initcall(regmap_initcall);