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 #include <linux/regmap.h>
  19
  20 struct regmap;
  21
  22 struct regmap_format {
  23         size_t buf_size;
  24         size_t reg_bytes;
  25         size_t val_bytes;
  26         void (*format_write)(struct regmap *map,
  27                              unsigned int reg, unsigned int val);
  28         void (*format_reg)(void *buf, unsigned int reg);
  29         void (*format_val)(void *buf, unsigned int val);
  30         unsigned int (*parse_val)(void *buf);
  31 };
  32
  33 struct regmap {
  34         struct mutex lock;
  35
  36         struct device *dev; /* Device we do I/O on */
  37         void *work_buf;     /* Scratch buffer used to format I/O */
  38         struct regmap_format format;  /* Buffer format */
  39         const struct regmap_bus *bus;
  40 };
  41
  42 static void regmap_format_4_12_write(struct regmap *map,
  43                                      unsigned int reg, unsigned int val)
  44 {
  45         __be16 *out = map->work_buf;
  46         *out = cpu_to_be16((reg << 12) | val);
  47 }
  48
  49 static void regmap_format_7_9_write(struct regmap *map,
  50                                     unsigned int reg, unsigned int val)
  51 {
  52         __be16 *out = map->work_buf;
  53         *out = cpu_to_be16((reg << 9) | val);
  54 }
  55
  56 static void regmap_format_8(void *buf, unsigned int val)
  57 {
  58         u8 *b = buf;
  59
  60         b[0] = val;
  61 }
  62
  63 static void regmap_format_16(void *buf, unsigned int val)
  64 {
  65         __be16 *b = buf;
  66
  67         b[0] = cpu_to_be16(val);
  68 }
  69
  70 static unsigned int regmap_parse_8(void *buf)
  71 {
  72         u8 *b = buf;
  73
  74         return b[0];
  75 }
  76
  77 static unsigned int regmap_parse_16(void *buf)
  78 {
  79         __be16 *b = buf;
  80
  81         b[0] = be16_to_cpu(b[0]);
  82
  83         return b[0];
  84 }
  85
  86 /**
  87  * regmap_init(): Initialise register map
  88  *
  89  * @dev: Device that will be interacted with
  90  * @bus: Bus-specific callbacks to use with device
  91  * @config: Configuration for register map
  92  *
  93  * The return value will be an ERR_PTR() on error or a valid pointer to
  94  * a struct regmap.  This function should generally not be called
  95  * directly, it should be called by bus-specific init functions.
  96  */
  97 struct regmap *regmap_init(struct device *dev,
  98                            const struct regmap_bus *bus,
  99                            const struct regmap_config *config)
 100 {
 101         struct regmap *map;
 102         int ret = -EINVAL;
 103
 104         if (!bus || !config)
 105                 return NULL;
 106
 107         map = kzalloc(sizeof(*map), GFP_KERNEL);
 108         if (map == NULL) {
 109                 ret = -ENOMEM;
 110                 goto err;
 111         }
 112
 113         mutex_init(&map->lock);
 114         map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
 115         map->format.reg_bytes = config->reg_bits / 8;
 116         map->format.val_bytes = config->val_bits / 8;
 117         map->dev = dev;
 118         map->bus = bus;
 119
 120         switch (config->reg_bits) {
 121         case 4:
 122                 switch (config->val_bits) {
 123                 case 12:
 124                         map->format.format_write = regmap_format_4_12_write;
 125                         break;
 126                 default:
 127                         goto err_map;
 128                 }
 129                 break;
 130
 131         case 7:
 132                 switch (config->val_bits) {
 133                 case 9:
 134                         map->format.format_write = regmap_format_7_9_write;
 135                         break;
 136                 default:
 137                         goto err_map;
 138                 }
 139                 break;
 140
 141         case 8:
 142                 map->format.format_reg = regmap_format_8;
 143                 break;
 144
 145         case 16:
 146                 map->format.format_reg = regmap_format_16;
 147                 break;
 148
 149         default:
 150                 goto err_map;
 151         }
 152
 153         switch (config->val_bits) {
 154         case 8:
 155                 map->format.format_val = regmap_format_8;
 156                 map->format.parse_val = regmap_parse_8;
 157                 break;
 158         case 16:
 159                 map->format.format_val = regmap_format_16;
 160                 map->format.parse_val = regmap_parse_16;
 161                 break;
 162         }
 163
 164         if (!map->format.format_write &&
 165             !(map->format.format_reg && map->format.format_val))
 166                 goto err_map;
 167
 168         map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
 169         if (map->work_buf == NULL) {
 170                 ret = -ENOMEM;
 171                 goto err_map;
 172         }
 173
 174         return map;
 175
 176 err_map:
 177         kfree(map);
 178 err:
 179         return ERR_PTR(ret);
 180 }
 181 EXPORT_SYMBOL_GPL(regmap_init);
 182
 183 /**
 184  * regmap_exit(): Free a previously allocated register map
 185  */
 186 void regmap_exit(struct regmap *map)
 187 {
 188         kfree(map->work_buf);
 189         kfree(map);
 190 }
 191 EXPORT_SYMBOL_GPL(regmap_exit);
 192
 193 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 194                              const void *val, size_t val_len)
 195 {
 196         void *buf;
 197         int ret = -ENOTSUPP;
 198         size_t len;
 199
 200         map->format.format_reg(map->work_buf, reg);
 201
 202         /* Try to do a gather write if we can */
 203         if (map->bus->gather_write)
 204                 ret = map->bus->gather_write(map->dev, map->work_buf,
 205                                              map->format.reg_bytes,
 206                                              val, val_len);
 207
 208         /* Otherwise fall back on linearising by hand. */
 209         if (ret == -ENOTSUPP) {
 210                 len = map->format.reg_bytes + val_len;
 211                 buf = kmalloc(len, GFP_KERNEL);
 212                 if (!buf)
 213                         return -ENOMEM;
 214
 215                 memcpy(buf, map->work_buf, map->format.reg_bytes);
 216                 memcpy(buf + map->format.reg_bytes, val, val_len);
 217                 ret = map->bus->write(map->dev, buf, len);
 218
 219                 kfree(buf);
 220         }
 221
 222         return ret;
 223 }
 224
 225 static int _regmap_write(struct regmap *map, unsigned int reg,
 226                          unsigned int val)
 227 {
 228         BUG_ON(!map->format.format_write && !map->format.format_val);
 229
 230         if (map->format.format_write) {
 231                 map->format.format_write(map, reg, val);
 232
 233                 return map->bus->write(map->dev, map->work_buf,
 234                                        map->format.buf_size);
 235         } else {
 236                 map->format.format_val(map->work_buf + map->format.reg_bytes,
 237                                        val);
 238                 return _regmap_raw_write(map, reg,
 239                                          map->work_buf + map->format.reg_bytes,
 240                                          map->format.val_bytes);
 241         }
 242 }
 243
 244 /**
 245  * regmap_write(): Write a value to a single register
 246  *
 247  * @map: Register map to write to
 248  * @reg: Register to write to
 249  * @val: Value to be written
 250  *
 251  * A value of zero will be returned on success, a negative errno will
 252  * be returned in error cases.
 253  */
 254 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 255 {
 256         int ret;
 257
 258         mutex_lock(&map->lock);
 259
 260         ret = _regmap_write(map, reg, val);
 261
 262         mutex_unlock(&map->lock);
 263
 264         return ret;
 265 }
 266 EXPORT_SYMBOL_GPL(regmap_write);
 267
 268 /**
 269  * regmap_raw_write(): Write raw values to one or more registers
 270  *
 271  * @map: Register map to write to
 272  * @reg: Initial register to write to
 273  * @val: Block of data to be written, laid out for direct transmission to the
 274  *       device
 275  * @val_len: Length of data pointed to by val.
 276  *
 277  * This function is intended to be used for things like firmware
 278  * download where a large block of data needs to be transferred to the
 279  * device.  No formatting will be done on the data provided.
 280  *
 281  * A value of zero will be returned on success, a negative errno will
 282  * be returned in error cases.
 283  */
 284 int regmap_raw_write(struct regmap *map, unsigned int reg,
 285                      const void *val, size_t val_len)
 286 {
 287         int ret;
 288
 289         mutex_lock(&map->lock);
 290
 291         ret = _regmap_raw_write(map, reg, val, val_len);
 292
 293         mutex_unlock(&map->lock);
 294
 295         return ret;
 296 }
 297 EXPORT_SYMBOL_GPL(regmap_raw_write);
 298
 299 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 300                             unsigned int val_len)
 301 {
 302         u8 *u8 = map->work_buf;
 303         int ret;
 304
 305         map->format.format_reg(map->work_buf, reg);
 306
 307         /*
 308          * Some buses flag reads by setting the high bits in the
 309          * register addresss; since it's always the high bits for all
 310          * current formats we can do this here rather than in
 311          * formatting.  This may break if we get interesting formats.
 312          */
 313         if (map->bus->read_flag_mask)
 314                 u8[0] |= map->bus->read_flag_mask;
 315
 316         ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
 317                              val, val_len);
 318         if (ret != 0)
 319                 return ret;
 320
 321         return 0;
 322 }
 323
 324 static int _regmap_read(struct regmap *map, unsigned int reg,
 325                         unsigned int *val)
 326 {
 327         int ret;
 328
 329         if (!map->format.parse_val)
 330                 return -EINVAL;
 331
 332         ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
 333         if (ret == 0)
 334                 *val = map->format.parse_val(map->work_buf);
 335
 336         return ret;
 337 }
 338
 339 /**
 340  * regmap_read(): Read a value from a single register
 341  *
 342  * @map: Register map to write to
 343  * @reg: Register to be read from
 344  * @val: Pointer to store read value
 345  *
 346  * A value of zero will be returned on success, a negative errno will
 347  * be returned in error cases.
 348  */
 349 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 350 {
 351         int ret;
 352
 353         mutex_lock(&map->lock);
 354
 355         ret = _regmap_read(map, reg, val);
 356
 357         mutex_unlock(&map->lock);
 358
 359         return ret;
 360 }
 361 EXPORT_SYMBOL_GPL(regmap_read);
 362
 363 /**
 364  * regmap_raw_read(): Read raw data from the device
 365  *
 366  * @map: Register map to write to
 367  * @reg: First register to be read from
 368  * @val: Pointer to store read value
 369  * @val_len: Size of data to read
 370  *
 371  * A value of zero will be returned on success, a negative errno will
 372  * be returned in error cases.
 373  */
 374 int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 375                     size_t val_len)
 376 {
 377         int ret;
 378
 379         mutex_lock(&map->lock);
 380
 381         ret = _regmap_raw_read(map, reg, val, val_len);
 382
 383         mutex_unlock(&map->lock);
 384
 385         return ret;
 386 }
 387 EXPORT_SYMBOL_GPL(regmap_raw_read);
 388
 389 /**
 390  * regmap_bulk_read(): Read multiple registers from the device
 391  *
 392  * @map: Register map to write to
 393  * @reg: First register to be read from
 394  * @val: Pointer to store read value, in native register size for device
 395  * @val_count: Number of registers to read
 396  *
 397  * A value of zero will be returned on success, a negative errno will
 398  * be returned in error cases.
 399  */
 400 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 401                      size_t val_count)
 402 {
 403         int ret, i;
 404         size_t val_bytes = map->format.val_bytes;
 405
 406         if (!map->format.parse_val)
 407                 return -EINVAL;
 408
 409         ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
 410         if (ret != 0)
 411                 return ret;
 412
 413         for (i = 0; i < val_count * val_bytes; i += val_bytes)
 414                 map->format.parse_val(val + i);
 415
 416         return 0;
 417 }
 418 EXPORT_SYMBOL_GPL(regmap_bulk_read);
 419
 420 /**
 421  * remap_update_bits: Perform a read/modify/write cycle on the register map
 422  *
 423  * @map: Register map to update
 424  * @reg: Register to update
 425  * @mask: Bitmask to change
 426  * @val: New value for bitmask
 427  *
 428  * Returns zero for success, a negative number on error.
 429  */
 430 int regmap_update_bits(struct regmap *map, unsigned int reg,
 431                        unsigned int mask, unsigned int val)
 432 {
 433         int ret;
 434         unsigned int tmp;
 435
 436         mutex_lock(&map->lock);
 437
 438         ret = _regmap_read(map, reg, &tmp);
 439         if (ret != 0)
 440                 goto out;
 441
 442         tmp &= ~mask;
 443         tmp |= val & mask;
 444
 445         ret = _regmap_write(map, reg, tmp);
 446
 447 out:
 448         mutex_unlock(&map->lock);
 449
 450         return ret;
 451 }
 452 EXPORT_SYMBOL_GPL(regmap_update_bits);