drivers/nvmem/core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * nvmem framework core.
   4  *
   5  * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
   6  * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/export.h>
  11 #include <linux/fs.h>
  12 #include <linux/idr.h>
  13 #include <linux/init.h>
  14 #include <linux/kref.h>
  15 #include <linux/module.h>
  16 #include <linux/nvmem-consumer.h>
  17 #include <linux/nvmem-provider.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/of.h>
  20 #include <linux/slab.h>
  21
  22 struct nvmem_device {
  23         struct module           *owner;
  24         struct device           dev;
  25         int                     stride;
  26         int                     word_size;
  27         int                     id;
  28         struct kref             refcnt;
  29         size_t                  size;
  30         bool                    read_only;
  31         bool                    root_only;
  32         int                     flags;
  33         enum nvmem_type         type;
  34         struct bin_attribute    eeprom;
  35         struct device           *base_dev;
  36         struct list_head        cells;
  37         const struct nvmem_keepout *keepout;
  38         unsigned int            nkeepout;
  39         nvmem_reg_read_t        reg_read;
  40         nvmem_reg_write_t       reg_write;
  41         struct gpio_desc        *wp_gpio;
  42         struct nvmem_layout     *layout;
  43         void *priv;
  44 };
  45
  46 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
  47
  48 #define FLAG_COMPAT             BIT(0)
  49 struct nvmem_cell_entry {
  50         const char              *name;
  51         int                     offset;
  52         size_t                  raw_len;
  53         int                     bytes;
  54         int                     bit_offset;
  55         int                     nbits;
  56         nvmem_cell_post_process_t read_post_process;
  57         void                    *priv;
  58         struct device_node      *np;
  59         struct nvmem_device     *nvmem;
  60         struct list_head        node;
  61 };
  62
  63 struct nvmem_cell {
  64         struct nvmem_cell_entry *entry;
  65         const char              *id;
  66         int                     index;
  67 };
  68
  69 static DEFINE_MUTEX(nvmem_mutex);
  70 static DEFINE_IDA(nvmem_ida);
  71
  72 static DEFINE_MUTEX(nvmem_cell_mutex);
  73 static LIST_HEAD(nvmem_cell_tables);
  74
  75 static DEFINE_MUTEX(nvmem_lookup_mutex);
  76 static LIST_HEAD(nvmem_lookup_list);
  77
  78 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
  79
  80 static DEFINE_SPINLOCK(nvmem_layout_lock);
  81 static LIST_HEAD(nvmem_layouts);
  82
  83 static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
  84                             void *val, size_t bytes)
  85 {
  86         if (nvmem->reg_read)
  87                 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
  88
  89         return -EINVAL;
  90 }
  91
  92 static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
  93                              void *val, size_t bytes)
  94 {
  95         int ret;
  96
  97         if (nvmem->reg_write) {
  98                 gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
  99                 ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
 100                 gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
 101                 return ret;
 102         }
 103
 104         return -EINVAL;
 105 }
 106
 107 static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
 108                                       unsigned int offset, void *val,
 109                                       size_t bytes, int write)
 110 {
 111
 112         unsigned int end = offset + bytes;
 113         unsigned int kend, ksize;
 114         const struct nvmem_keepout *keepout = nvmem->keepout;
 115         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
 116         int rc;
 117
 118         /*
 119          * Skip all keepouts before the range being accessed.
 120          * Keepouts are sorted.
 121          */
 122         while ((keepout < keepoutend) && (keepout->end <= offset))
 123                 keepout++;
 124
 125         while ((offset < end) && (keepout < keepoutend)) {
 126                 /* Access the valid portion before the keepout. */
 127                 if (offset < keepout->start) {
 128                         kend = min(end, keepout->start);
 129                         ksize = kend - offset;
 130                         if (write)
 131                                 rc = __nvmem_reg_write(nvmem, offset, val, ksize);
 132                         else
 133                                 rc = __nvmem_reg_read(nvmem, offset, val, ksize);
 134
 135                         if (rc)
 136                                 return rc;
 137
 138                         offset += ksize;
 139                         val += ksize;
 140                 }
 141
 142                 /*
 143                  * Now we're aligned to the start of this keepout zone. Go
 144                  * through it.
 145                  */
 146                 kend = min(end, keepout->end);
 147                 ksize = kend - offset;
 148                 if (!write)
 149                         memset(val, keepout->value, ksize);
 150
 151                 val += ksize;
 152                 offset += ksize;
 153                 keepout++;
 154         }
 155
 156         /*
 157          * If we ran out of keepouts but there's still stuff to do, send it
 158          * down directly
 159          */
 160         if (offset < end) {
 161                 ksize = end - offset;
 162                 if (write)
 163                         return __nvmem_reg_write(nvmem, offset, val, ksize);
 164                 else
 165                         return __nvmem_reg_read(nvmem, offset, val, ksize);
 166         }
 167
 168         return 0;
 169 }
 170
 171 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 172                           void *val, size_t bytes)
 173 {
 174         if (!nvmem->nkeepout)
 175                 return __nvmem_reg_read(nvmem, offset, val, bytes);
 176
 177         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
 178 }
 179
 180 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
 181                            void *val, size_t bytes)
 182 {
 183         if (!nvmem->nkeepout)
 184                 return __nvmem_reg_write(nvmem, offset, val, bytes);
 185
 186         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true);
 187 }
 188
 189 #ifdef CONFIG_NVMEM_SYSFS
 190 static const char * const nvmem_type_str[] = {
 191         [NVMEM_TYPE_UNKNOWN] = "Unknown",
 192         [NVMEM_TYPE_EEPROM] = "EEPROM",
 193         [NVMEM_TYPE_OTP] = "OTP",
 194         [NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
 195         [NVMEM_TYPE_FRAM] = "FRAM",
 196 };
 197
 198 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 199 static struct lock_class_key eeprom_lock_key;
 200 #endif
 201
 202 static ssize_t type_show(struct device *dev,
 203                          struct device_attribute *attr, char *buf)
 204 {
 205         struct nvmem_device *nvmem = to_nvmem_device(dev);
 206
 207         return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]);
 208 }
 209
 210 static DEVICE_ATTR_RO(type);
 211
 212 static struct attribute *nvmem_attrs[] = {
 213         &dev_attr_type.attr,
 214         NULL,
 215 };
 216
 217 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
 218                                    struct bin_attribute *attr, char *buf,
 219                                    loff_t pos, size_t count)
 220 {
 221         struct device *dev;
 222         struct nvmem_device *nvmem;
 223         int rc;
 224
 225         if (attr->private)
 226                 dev = attr->private;
 227         else
 228                 dev = kobj_to_dev(kobj);
 229         nvmem = to_nvmem_device(dev);
 230
 231         /* Stop the user from reading */
 232         if (pos >= nvmem->size)
 233                 return 0;
 234
 235         if (!IS_ALIGNED(pos, nvmem->stride))
 236                 return -EINVAL;
 237
 238         if (count < nvmem->word_size)
 239                 return -EINVAL;
 240
 241         if (pos + count > nvmem->size)
 242                 count = nvmem->size - pos;
 243
 244         count = round_down(count, nvmem->word_size);
 245
 246         if (!nvmem->reg_read)
 247                 return -EPERM;
 248
 249         rc = nvmem_reg_read(nvmem, pos, buf, count);
 250
 251         if (rc)
 252                 return rc;
 253
 254         return count;
 255 }
 256
 257 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
 258                                     struct bin_attribute *attr, char *buf,
 259                                     loff_t pos, size_t count)
 260 {
 261         struct device *dev;
 262         struct nvmem_device *nvmem;
 263         int rc;
 264
 265         if (attr->private)
 266                 dev = attr->private;
 267         else
 268                 dev = kobj_to_dev(kobj);
 269         nvmem = to_nvmem_device(dev);
 270
 271         /* Stop the user from writing */
 272         if (pos >= nvmem->size)
 273                 return -EFBIG;
 274
 275         if (!IS_ALIGNED(pos, nvmem->stride))
 276                 return -EINVAL;
 277
 278         if (count < nvmem->word_size)
 279                 return -EINVAL;
 280
 281         if (pos + count > nvmem->size)
 282                 count = nvmem->size - pos;
 283
 284         count = round_down(count, nvmem->word_size);
 285
 286         if (!nvmem->reg_write)
 287                 return -EPERM;
 288
 289         rc = nvmem_reg_write(nvmem, pos, buf, count);
 290
 291         if (rc)
 292                 return rc;
 293
 294         return count;
 295 }
 296
 297 static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
 298 {
 299         umode_t mode = 0400;
 300
 301         if (!nvmem->root_only)
 302                 mode |= 0044;
 303
 304         if (!nvmem->read_only)
 305                 mode |= 0200;
 306
 307         if (!nvmem->reg_write)
 308                 mode &= ~0200;
 309
 310         if (!nvmem->reg_read)
 311                 mode &= ~0444;
 312
 313         return mode;
 314 }
 315
 316 static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
 317                                          struct bin_attribute *attr, int i)
 318 {
 319         struct device *dev = kobj_to_dev(kobj);
 320         struct nvmem_device *nvmem = to_nvmem_device(dev);
 321
 322         attr->size = nvmem->size;
 323
 324         return nvmem_bin_attr_get_umode(nvmem);
 325 }
 326
 327 /* default read/write permissions */
 328 static struct bin_attribute bin_attr_rw_nvmem = {
 329         .attr   = {
 330                 .name   = "nvmem",
 331                 .mode   = 0644,
 332         },
 333         .read   = bin_attr_nvmem_read,
 334         .write  = bin_attr_nvmem_write,
 335 };
 336
 337 static struct bin_attribute *nvmem_bin_attributes[] = {
 338         &bin_attr_rw_nvmem,
 339         NULL,
 340 };
 341
 342 static const struct attribute_group nvmem_bin_group = {
 343         .bin_attrs      = nvmem_bin_attributes,
 344         .attrs          = nvmem_attrs,
 345         .is_bin_visible = nvmem_bin_attr_is_visible,
 346 };
 347
 348 static const struct attribute_group *nvmem_dev_groups[] = {
 349         &nvmem_bin_group,
 350         NULL,
 351 };
 352
 353 static struct bin_attribute bin_attr_nvmem_eeprom_compat = {
 354         .attr   = {
 355                 .name   = "eeprom",
 356         },
 357         .read   = bin_attr_nvmem_read,
 358         .write  = bin_attr_nvmem_write,
 359 };
 360
 361 /*
 362  * nvmem_setup_compat() - Create an additional binary entry in
 363  * drivers sys directory, to be backwards compatible with the older
 364  * drivers/misc/eeprom drivers.
 365  */
 366 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 367                                     const struct nvmem_config *config)
 368 {
 369         int rval;
 370
 371         if (!config->compat)
 372                 return 0;
 373
 374         if (!config->base_dev)
 375                 return -EINVAL;
 376
 377         if (config->type == NVMEM_TYPE_FRAM)
 378                 bin_attr_nvmem_eeprom_compat.attr.name = "fram";
 379
 380         nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
 381         nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
 382         nvmem->eeprom.size = nvmem->size;
 383 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 384         nvmem->eeprom.attr.key = &eeprom_lock_key;
 385 #endif
 386         nvmem->eeprom.private = &nvmem->dev;
 387         nvmem->base_dev = config->base_dev;
 388
 389         rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
 390         if (rval) {
 391                 dev_err(&nvmem->dev,
 392                         "Failed to create eeprom binary file %d\n", rval);
 393                 return rval;
 394         }
 395
 396         nvmem->flags |= FLAG_COMPAT;
 397
 398         return 0;
 399 }
 400
 401 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 402                               const struct nvmem_config *config)
 403 {
 404         if (config->compat)
 405                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 406 }
 407
 408 #else /* CONFIG_NVMEM_SYSFS */
 409
 410 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 411                                     const struct nvmem_config *config)
 412 {
 413         return -ENOSYS;
 414 }
 415 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 416                                       const struct nvmem_config *config)
 417 {
 418 }
 419
 420 #endif /* CONFIG_NVMEM_SYSFS */
 421
 422 static void nvmem_release(struct device *dev)
 423 {
 424         struct nvmem_device *nvmem = to_nvmem_device(dev);
 425
 426         ida_free(&nvmem_ida, nvmem->id);
 427         gpiod_put(nvmem->wp_gpio);
 428         kfree(nvmem);
 429 }
 430
 431 static const struct device_type nvmem_provider_type = {
 432         .release        = nvmem_release,
 433 };
 434
 435 static struct bus_type nvmem_bus_type = {
 436         .name           = "nvmem",
 437 };
 438
 439 static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell)
 440 {
 441         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
 442         mutex_lock(&nvmem_mutex);
 443         list_del(&cell->node);
 444         mutex_unlock(&nvmem_mutex);
 445         of_node_put(cell->np);
 446         kfree_const(cell->name);
 447         kfree(cell);
 448 }
 449
 450 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
 451 {
 452         struct nvmem_cell_entry *cell, *p;
 453
 454         list_for_each_entry_safe(cell, p, &nvmem->cells, node)
 455                 nvmem_cell_entry_drop(cell);
 456 }
 457
 458 static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell)
 459 {
 460         mutex_lock(&nvmem_mutex);
 461         list_add_tail(&cell->node, &cell->nvmem->cells);
 462         mutex_unlock(&nvmem_mutex);
 463         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
 464 }
 465
 466 static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 467                                                      const struct nvmem_cell_info *info,
 468                                                      struct nvmem_cell_entry *cell)
 469 {
 470         cell->nvmem = nvmem;
 471         cell->offset = info->offset;
 472         cell->raw_len = info->raw_len ?: info->bytes;
 473         cell->bytes = info->bytes;
 474         cell->name = info->name;
 475         cell->read_post_process = info->read_post_process;
 476         cell->priv = info->priv;
 477
 478         cell->bit_offset = info->bit_offset;
 479         cell->nbits = info->nbits;
 480         cell->np = info->np;
 481
 482         if (cell->nbits)
 483                 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
 484                                            BITS_PER_BYTE);
 485
 486         if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 487                 dev_err(&nvmem->dev,
 488                         "cell %s unaligned to nvmem stride %d\n",
 489                         cell->name ?: "<unknown>", nvmem->stride);
 490                 return -EINVAL;
 491         }
 492
 493         return 0;
 494 }
 495
 496 static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 497                                                const struct nvmem_cell_info *info,
 498                                                struct nvmem_cell_entry *cell)
 499 {
 500         int err;
 501
 502         err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell);
 503         if (err)
 504                 return err;
 505
 506         cell->name = kstrdup_const(info->name, GFP_KERNEL);
 507         if (!cell->name)
 508                 return -ENOMEM;
 509
 510         return 0;
 511 }
 512
 513 /**
 514  * nvmem_add_one_cell() - Add one cell information to an nvmem device
 515  *
 516  * @nvmem: nvmem device to add cells to.
 517  * @info: nvmem cell info to add to the device
 518  *
 519  * Return: 0 or negative error code on failure.
 520  */
 521 int nvmem_add_one_cell(struct nvmem_device *nvmem,
 522                        const struct nvmem_cell_info *info)
 523 {
 524         struct nvmem_cell_entry *cell;
 525         int rval;
 526
 527         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 528         if (!cell)
 529                 return -ENOMEM;
 530
 531         rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 532         if (rval) {
 533                 kfree(cell);
 534                 return rval;
 535         }
 536
 537         nvmem_cell_entry_add(cell);
 538
 539         return 0;
 540 }
 541 EXPORT_SYMBOL_GPL(nvmem_add_one_cell);
 542
 543 /**
 544  * nvmem_add_cells() - Add cell information to an nvmem device
 545  *
 546  * @nvmem: nvmem device to add cells to.
 547  * @info: nvmem cell info to add to the device
 548  * @ncells: number of cells in info
 549  *
 550  * Return: 0 or negative error code on failure.
 551  */
 552 static int nvmem_add_cells(struct nvmem_device *nvmem,
 553                     const struct nvmem_cell_info *info,
 554                     int ncells)
 555 {
 556         int i, rval;
 557
 558         for (i = 0; i < ncells; i++) {
 559                 rval = nvmem_add_one_cell(nvmem, &info[i]);
 560                 if (rval)
 561                         return rval;
 562         }
 563
 564         return 0;
 565 }
 566
 567 /**
 568  * nvmem_register_notifier() - Register a notifier block for nvmem events.
 569  *
 570  * @nb: notifier block to be called on nvmem events.
 571  *
 572  * Return: 0 on success, negative error number on failure.
 573  */
 574 int nvmem_register_notifier(struct notifier_block *nb)
 575 {
 576         return blocking_notifier_chain_register(&nvmem_notifier, nb);
 577 }
 578 EXPORT_SYMBOL_GPL(nvmem_register_notifier);
 579
 580 /**
 581  * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
 582  *
 583  * @nb: notifier block to be unregistered.
 584  *
 585  * Return: 0 on success, negative error number on failure.
 586  */
 587 int nvmem_unregister_notifier(struct notifier_block *nb)
 588 {
 589         return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
 590 }
 591 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
 592
 593 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
 594 {
 595         const struct nvmem_cell_info *info;
 596         struct nvmem_cell_table *table;
 597         struct nvmem_cell_entry *cell;
 598         int rval = 0, i;
 599
 600         mutex_lock(&nvmem_cell_mutex);
 601         list_for_each_entry(table, &nvmem_cell_tables, node) {
 602                 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
 603                         for (i = 0; i < table->ncells; i++) {
 604                                 info = &table->cells[i];
 605
 606                                 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 607                                 if (!cell) {
 608                                         rval = -ENOMEM;
 609                                         goto out;
 610                                 }
 611
 612                                 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 613                                 if (rval) {
 614                                         kfree(cell);
 615                                         goto out;
 616                                 }
 617
 618                                 nvmem_cell_entry_add(cell);
 619                         }
 620                 }
 621         }
 622
 623 out:
 624         mutex_unlock(&nvmem_cell_mutex);
 625         return rval;
 626 }
 627
 628 static struct nvmem_cell_entry *
 629 nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id)
 630 {
 631         struct nvmem_cell_entry *iter, *cell = NULL;
 632
 633         mutex_lock(&nvmem_mutex);
 634         list_for_each_entry(iter, &nvmem->cells, node) {
 635                 if (strcmp(cell_id, iter->name) == 0) {
 636                         cell = iter;
 637                         break;
 638                 }
 639         }
 640         mutex_unlock(&nvmem_mutex);
 641
 642         return cell;
 643 }
 644
 645 static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 646 {
 647         unsigned int cur = 0;
 648         const struct nvmem_keepout *keepout = nvmem->keepout;
 649         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
 650
 651         while (keepout < keepoutend) {
 652                 /* Ensure keepouts are sorted and don't overlap. */
 653                 if (keepout->start < cur) {
 654                         dev_err(&nvmem->dev,
 655                                 "Keepout regions aren't sorted or overlap.\n");
 656
 657                         return -ERANGE;
 658                 }
 659
 660                 if (keepout->end < keepout->start) {
 661                         dev_err(&nvmem->dev,
 662                                 "Invalid keepout region.\n");
 663
 664                         return -EINVAL;
 665                 }
 666
 667                 /*
 668                  * Validate keepouts (and holes between) don't violate
 669                  * word_size constraints.
 670                  */
 671                 if ((keepout->end - keepout->start < nvmem->word_size) ||
 672                     ((keepout->start != cur) &&
 673                      (keepout->start - cur < nvmem->word_size))) {
 674
 675                         dev_err(&nvmem->dev,
 676                                 "Keepout regions violate word_size constraints.\n");
 677
 678                         return -ERANGE;
 679                 }
 680
 681                 /* Validate keepouts don't violate stride (alignment). */
 682                 if (!IS_ALIGNED(keepout->start, nvmem->stride) ||
 683                     !IS_ALIGNED(keepout->end, nvmem->stride)) {
 684
 685                         dev_err(&nvmem->dev,
 686                                 "Keepout regions violate stride.\n");
 687
 688                         return -EINVAL;
 689                 }
 690
 691                 cur = keepout->end;
 692                 keepout++;
 693         }
 694
 695         return 0;
 696 }
 697
 698 static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np)
 699 {
 700         struct nvmem_layout *layout = nvmem->layout;
 701         struct device *dev = &nvmem->dev;
 702         struct device_node *child;
 703         const __be32 *addr;
 704         int len, ret;
 705
 706         for_each_child_of_node(np, child) {
 707                 struct nvmem_cell_info info = {0};
 708
 709                 addr = of_get_property(child, "reg", &len);
 710                 if (!addr)
 711                         continue;
 712                 if (len < 2 * sizeof(u32)) {
 713                         dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
 714                         of_node_put(child);
 715                         return -EINVAL;
 716                 }
 717
 718                 info.offset = be32_to_cpup(addr++);
 719                 info.bytes = be32_to_cpup(addr);
 720                 info.name = kasprintf(GFP_KERNEL, "%pOFn", child);
 721
 722                 addr = of_get_property(child, "bits", &len);
 723                 if (addr && len == (2 * sizeof(u32))) {
 724                         info.bit_offset = be32_to_cpup(addr++);
 725                         info.nbits = be32_to_cpup(addr);
 726                 }
 727
 728                 info.np = of_node_get(child);
 729
 730                 if (layout && layout->fixup_cell_info)
 731                         layout->fixup_cell_info(nvmem, layout, &info);
 732
 733                 ret = nvmem_add_one_cell(nvmem, &info);
 734                 kfree(info.name);
 735                 if (ret) {
 736                         of_node_put(child);
 737                         return ret;
 738                 }
 739         }
 740
 741         return 0;
 742 }
 743
 744 static int nvmem_add_cells_from_legacy_of(struct nvmem_device *nvmem)
 745 {
 746         return nvmem_add_cells_from_dt(nvmem, nvmem->dev.of_node);
 747 }
 748
 749 static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem)
 750 {
 751         struct device_node *layout_np;
 752         int err = 0;
 753
 754         layout_np = of_nvmem_layout_get_container(nvmem);
 755         if (!layout_np)
 756                 return 0;
 757
 758         if (of_device_is_compatible(layout_np, "fixed-layout"))
 759                 err = nvmem_add_cells_from_dt(nvmem, layout_np);
 760
 761         of_node_put(layout_np);
 762
 763         return err;
 764 }
 765
 766 int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner)
 767 {
 768         layout->owner = owner;
 769
 770         spin_lock(&nvmem_layout_lock);
 771         list_add(&layout->node, &nvmem_layouts);
 772         spin_unlock(&nvmem_layout_lock);
 773
 774         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_LAYOUT_ADD, layout);
 775
 776         return 0;
 777 }
 778 EXPORT_SYMBOL_GPL(__nvmem_layout_register);
 779
 780 void nvmem_layout_unregister(struct nvmem_layout *layout)
 781 {
 782         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_LAYOUT_REMOVE, layout);
 783
 784         spin_lock(&nvmem_layout_lock);
 785         list_del(&layout->node);
 786         spin_unlock(&nvmem_layout_lock);
 787 }
 788 EXPORT_SYMBOL_GPL(nvmem_layout_unregister);
 789
 790 static struct nvmem_layout *nvmem_layout_get(struct nvmem_device *nvmem)
 791 {
 792         struct device_node *layout_np;
 793         struct nvmem_layout *l, *layout = ERR_PTR(-EPROBE_DEFER);
 794
 795         layout_np = of_nvmem_layout_get_container(nvmem);
 796         if (!layout_np)
 797                 return NULL;
 798
 799         /* Fixed layouts don't have a matching driver */
 800         if (of_device_is_compatible(layout_np, "fixed-layout")) {
 801                 of_node_put(layout_np);
 802                 return NULL;
 803         }
 804
 805         /*
 806          * In case the nvmem device was built-in while the layout was built as a
 807          * module, we shall manually request the layout driver loading otherwise
 808          * we'll never have any match.
 809          */
 810         of_request_module(layout_np);
 811
 812         spin_lock(&nvmem_layout_lock);
 813
 814         list_for_each_entry(l, &nvmem_layouts, node) {
 815                 if (of_match_node(l->of_match_table, layout_np)) {
 816                         if (try_module_get(l->owner))
 817                                 layout = l;
 818
 819                         break;
 820                 }
 821         }
 822
 823         spin_unlock(&nvmem_layout_lock);
 824         of_node_put(layout_np);
 825
 826         return layout;
 827 }
 828
 829 static void nvmem_layout_put(struct nvmem_layout *layout)
 830 {
 831         if (layout)
 832                 module_put(layout->owner);
 833 }
 834
 835 static int nvmem_add_cells_from_layout(struct nvmem_device *nvmem)
 836 {
 837         struct nvmem_layout *layout = nvmem->layout;
 838         int ret;
 839
 840         if (layout && layout->add_cells) {
 841                 ret = layout->add_cells(&nvmem->dev, nvmem, layout);
 842                 if (ret)
 843                         return ret;
 844         }
 845
 846         return 0;
 847 }
 848
 849 #if IS_ENABLED(CONFIG_OF)
 850 /**
 851  * of_nvmem_layout_get_container() - Get OF node to layout container.
 852  *
 853  * @nvmem: nvmem device.
 854  *
 855  * Return: a node pointer with refcount incremented or NULL if no
 856  * container exists. Use of_node_put() on it when done.
 857  */
 858 struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
 859 {
 860         return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
 861 }
 862 EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
 863 #endif
 864
 865 const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
 866                                         struct nvmem_layout *layout)
 867 {
 868         struct device_node __maybe_unused *layout_np;
 869         const struct of_device_id *match;
 870
 871         layout_np = of_nvmem_layout_get_container(nvmem);
 872         match = of_match_node(layout->of_match_table, layout_np);
 873
 874         return match ? match->data : NULL;
 875 }
 876 EXPORT_SYMBOL_GPL(nvmem_layout_get_match_data);
 877
 878 /**
 879  * nvmem_register() - Register a nvmem device for given nvmem_config.
 880  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 881  *
 882  * @config: nvmem device configuration with which nvmem device is created.
 883  *
 884  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 885  * on success.
 886  */
 887
 888 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 889 {
 890         struct nvmem_device *nvmem;
 891         int rval;
 892
 893         if (!config->dev)
 894                 return ERR_PTR(-EINVAL);
 895
 896         if (!config->reg_read && !config->reg_write)
 897                 return ERR_PTR(-EINVAL);
 898
 899         nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
 900         if (!nvmem)
 901                 return ERR_PTR(-ENOMEM);
 902
 903         rval = ida_alloc(&nvmem_ida, GFP_KERNEL);
 904         if (rval < 0) {
 905                 kfree(nvmem);
 906                 return ERR_PTR(rval);
 907         }
 908
 909         nvmem->id = rval;
 910
 911         nvmem->dev.type = &nvmem_provider_type;
 912         nvmem->dev.bus = &nvmem_bus_type;
 913         nvmem->dev.parent = config->dev;
 914
 915         device_initialize(&nvmem->dev);
 916
 917         if (!config->ignore_wp)
 918                 nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
 919                                                     GPIOD_OUT_HIGH);
 920         if (IS_ERR(nvmem->wp_gpio)) {
 921                 rval = PTR_ERR(nvmem->wp_gpio);
 922                 nvmem->wp_gpio = NULL;
 923                 goto err_put_device;
 924         }
 925
 926         kref_init(&nvmem->refcnt);
 927         INIT_LIST_HEAD(&nvmem->cells);
 928
 929         nvmem->owner = config->owner;
 930         if (!nvmem->owner && config->dev->driver)
 931                 nvmem->owner = config->dev->driver->owner;
 932         nvmem->stride = config->stride ?: 1;
 933         nvmem->word_size = config->word_size ?: 1;
 934         nvmem->size = config->size;
 935         nvmem->root_only = config->root_only;
 936         nvmem->priv = config->priv;
 937         nvmem->type = config->type;
 938         nvmem->reg_read = config->reg_read;
 939         nvmem->reg_write = config->reg_write;
 940         nvmem->keepout = config->keepout;
 941         nvmem->nkeepout = config->nkeepout;
 942         if (config->of_node)
 943                 nvmem->dev.of_node = config->of_node;
 944         else if (!config->no_of_node)
 945                 nvmem->dev.of_node = config->dev->of_node;
 946
 947         switch (config->id) {
 948         case NVMEM_DEVID_NONE:
 949                 rval = dev_set_name(&nvmem->dev, "%s", config->name);
 950                 break;
 951         case NVMEM_DEVID_AUTO:
 952                 rval = dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
 953                 break;
 954         default:
 955                 rval = dev_set_name(&nvmem->dev, "%s%d",
 956                              config->name ? : "nvmem",
 957                              config->name ? config->id : nvmem->id);
 958                 break;
 959         }
 960
 961         if (rval)
 962                 goto err_put_device;
 963
 964         nvmem->read_only = device_property_present(config->dev, "read-only") ||
 965                            config->read_only || !nvmem->reg_write;
 966
 967 #ifdef CONFIG_NVMEM_SYSFS
 968         nvmem->dev.groups = nvmem_dev_groups;
 969 #endif
 970
 971         if (nvmem->nkeepout) {
 972                 rval = nvmem_validate_keepouts(nvmem);
 973                 if (rval)
 974                         goto err_put_device;
 975         }
 976
 977         if (config->compat) {
 978                 rval = nvmem_sysfs_setup_compat(nvmem, config);
 979                 if (rval)
 980                         goto err_put_device;
 981         }
 982
 983         /*
 984          * If the driver supplied a layout by config->layout, the module
 985          * pointer will be NULL and nvmem_layout_put() will be a noop.
 986          */
 987         nvmem->layout = config->layout ?: nvmem_layout_get(nvmem);
 988         if (IS_ERR(nvmem->layout)) {
 989                 rval = PTR_ERR(nvmem->layout);
 990                 nvmem->layout = NULL;
 991
 992                 if (rval == -EPROBE_DEFER)
 993                         goto err_teardown_compat;
 994         }
 995
 996         if (config->cells) {
 997                 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
 998                 if (rval)
 999                         goto err_remove_cells;
1000         }
1001
1002         rval = nvmem_add_cells_from_table(nvmem);
1003         if (rval)
1004                 goto err_remove_cells;
1005
1006         rval = nvmem_add_cells_from_legacy_of(nvmem);
1007         if (rval)
1008                 goto err_remove_cells;
1009
1010         rval = nvmem_add_cells_from_fixed_layout(nvmem);
1011         if (rval)
1012                 goto err_remove_cells;
1013
1014         rval = nvmem_add_cells_from_layout(nvmem);
1015         if (rval)
1016                 goto err_remove_cells;
1017
1018         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
1019
1020         rval = device_add(&nvmem->dev);
1021         if (rval)
1022                 goto err_remove_cells;
1023
1024         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
1025
1026         return nvmem;
1027
1028 err_remove_cells:
1029         nvmem_device_remove_all_cells(nvmem);
1030         nvmem_layout_put(nvmem->layout);
1031 err_teardown_compat:
1032         if (config->compat)
1033                 nvmem_sysfs_remove_compat(nvmem, config);
1034 err_put_device:
1035         put_device(&nvmem->dev);
1036
1037         return ERR_PTR(rval);
1038 }
1039 EXPORT_SYMBOL_GPL(nvmem_register);
1040
1041 static void nvmem_device_release(struct kref *kref)
1042 {
1043         struct nvmem_device *nvmem;
1044
1045         nvmem = container_of(kref, struct nvmem_device, refcnt);
1046
1047         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
1048
1049         if (nvmem->flags & FLAG_COMPAT)
1050                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
1051
1052         nvmem_device_remove_all_cells(nvmem);
1053         nvmem_layout_put(nvmem->layout);
1054         device_unregister(&nvmem->dev);
1055 }
1056
1057 /**
1058  * nvmem_unregister() - Unregister previously registered nvmem device
1059  *
1060  * @nvmem: Pointer to previously registered nvmem device.
1061  */
1062 void nvmem_unregister(struct nvmem_device *nvmem)
1063 {
1064         if (nvmem)
1065                 kref_put(&nvmem->refcnt, nvmem_device_release);
1066 }
1067 EXPORT_SYMBOL_GPL(nvmem_unregister);
1068
1069 static void devm_nvmem_unregister(void *nvmem)
1070 {
1071         nvmem_unregister(nvmem);
1072 }
1073
1074 /**
1075  * devm_nvmem_register() - Register a managed nvmem device for given
1076  * nvmem_config.
1077  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
1078  *
1079  * @dev: Device that uses the nvmem device.
1080  * @config: nvmem device configuration with which nvmem device is created.
1081  *
1082  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
1083  * on success.
1084  */
1085 struct nvmem_device *devm_nvmem_register(struct device *dev,
1086                                          const struct nvmem_config *config)
1087 {
1088         struct nvmem_device *nvmem;
1089         int ret;
1090
1091         nvmem = nvmem_register(config);
1092         if (IS_ERR(nvmem))
1093                 return nvmem;
1094
1095         ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem);
1096         if (ret)
1097                 return ERR_PTR(ret);
1098
1099         return nvmem;
1100 }
1101 EXPORT_SYMBOL_GPL(devm_nvmem_register);
1102
1103 static struct nvmem_device *__nvmem_device_get(void *data,
1104                         int (*match)(struct device *dev, const void *data))
1105 {
1106         struct nvmem_device *nvmem = NULL;
1107         struct device *dev;
1108
1109         mutex_lock(&nvmem_mutex);
1110         dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
1111         if (dev)
1112                 nvmem = to_nvmem_device(dev);
1113         mutex_unlock(&nvmem_mutex);
1114         if (!nvmem)
1115                 return ERR_PTR(-EPROBE_DEFER);
1116
1117         if (!try_module_get(nvmem->owner)) {
1118                 dev_err(&nvmem->dev,
1119                         "could not increase module refcount for cell %s\n",
1120                         nvmem_dev_name(nvmem));
1121
1122                 put_device(&nvmem->dev);
1123                 return ERR_PTR(-EINVAL);
1124         }
1125
1126         kref_get(&nvmem->refcnt);
1127
1128         return nvmem;
1129 }
1130
1131 static void __nvmem_device_put(struct nvmem_device *nvmem)
1132 {
1133         put_device(&nvmem->dev);
1134         module_put(nvmem->owner);
1135         kref_put(&nvmem->refcnt, nvmem_device_release);
1136 }
1137
1138 #if IS_ENABLED(CONFIG_OF)
1139 /**
1140  * of_nvmem_device_get() - Get nvmem device from a given id
1141  *
1142  * @np: Device tree node that uses the nvmem device.
1143  * @id: nvmem name from nvmem-names property.
1144  *
1145  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1146  * on success.
1147  */
1148 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
1149 {
1150
1151         struct device_node *nvmem_np;
1152         struct nvmem_device *nvmem;
1153         int index = 0;
1154
1155         if (id)
1156                 index = of_property_match_string(np, "nvmem-names", id);
1157
1158         nvmem_np = of_parse_phandle(np, "nvmem", index);
1159         if (!nvmem_np)
1160                 return ERR_PTR(-ENOENT);
1161
1162         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1163         of_node_put(nvmem_np);
1164         return nvmem;
1165 }
1166 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
1167 #endif
1168
1169 /**
1170  * nvmem_device_get() - Get nvmem device from a given id
1171  *
1172  * @dev: Device that uses the nvmem device.
1173  * @dev_name: name of the requested nvmem device.
1174  *
1175  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1176  * on success.
1177  */
1178 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
1179 {
1180         if (dev->of_node) { /* try dt first */
1181                 struct nvmem_device *nvmem;
1182
1183                 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
1184
1185                 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
1186                         return nvmem;
1187
1188         }
1189
1190         return __nvmem_device_get((void *)dev_name, device_match_name);
1191 }
1192 EXPORT_SYMBOL_GPL(nvmem_device_get);
1193
1194 /**
1195  * nvmem_device_find() - Find nvmem device with matching function
1196  *
1197  * @data: Data to pass to match function
1198  * @match: Callback function to check device
1199  *
1200  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1201  * on success.
1202  */
1203 struct nvmem_device *nvmem_device_find(void *data,
1204                         int (*match)(struct device *dev, const void *data))
1205 {
1206         return __nvmem_device_get(data, match);
1207 }
1208 EXPORT_SYMBOL_GPL(nvmem_device_find);
1209
1210 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
1211 {
1212         struct nvmem_device **nvmem = res;
1213
1214         if (WARN_ON(!nvmem || !*nvmem))
1215                 return 0;
1216
1217         return *nvmem == data;
1218 }
1219
1220 static void devm_nvmem_device_release(struct device *dev, void *res)
1221 {
1222         nvmem_device_put(*(struct nvmem_device **)res);
1223 }
1224
1225 /**
1226  * devm_nvmem_device_put() - put alredy got nvmem device
1227  *
1228  * @dev: Device that uses the nvmem device.
1229  * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
1230  * that needs to be released.
1231  */
1232 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
1233 {
1234         int ret;
1235
1236         ret = devres_release(dev, devm_nvmem_device_release,
1237                              devm_nvmem_device_match, nvmem);
1238
1239         WARN_ON(ret);
1240 }
1241 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
1242
1243 /**
1244  * nvmem_device_put() - put alredy got nvmem device
1245  *
1246  * @nvmem: pointer to nvmem device that needs to be released.
1247  */
1248 void nvmem_device_put(struct nvmem_device *nvmem)
1249 {
1250         __nvmem_device_put(nvmem);
1251 }
1252 EXPORT_SYMBOL_GPL(nvmem_device_put);
1253
1254 /**
1255  * devm_nvmem_device_get() - Get nvmem cell of device form a given id
1256  *
1257  * @dev: Device that requests the nvmem device.
1258  * @id: name id for the requested nvmem device.
1259  *
1260  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
1261  * on success.  The nvmem_cell will be freed by the automatically once the
1262  * device is freed.
1263  */
1264 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
1265 {
1266         struct nvmem_device **ptr, *nvmem;
1267
1268         ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
1269         if (!ptr)
1270                 return ERR_PTR(-ENOMEM);
1271
1272         nvmem = nvmem_device_get(dev, id);
1273         if (!IS_ERR(nvmem)) {
1274                 *ptr = nvmem;
1275                 devres_add(dev, ptr);
1276         } else {
1277                 devres_free(ptr);
1278         }
1279
1280         return nvmem;
1281 }
1282 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
1283
1284 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
1285                                             const char *id, int index)
1286 {
1287         struct nvmem_cell *cell;
1288         const char *name = NULL;
1289
1290         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
1291         if (!cell)
1292                 return ERR_PTR(-ENOMEM);
1293
1294         if (id) {
1295                 name = kstrdup_const(id, GFP_KERNEL);
1296                 if (!name) {
1297                         kfree(cell);
1298                         return ERR_PTR(-ENOMEM);
1299                 }
1300         }
1301
1302         cell->id = name;
1303         cell->entry = entry;
1304         cell->index = index;
1305
1306         return cell;
1307 }
1308
1309 static struct nvmem_cell *
1310 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
1311 {
1312         struct nvmem_cell_entry *cell_entry;
1313         struct nvmem_cell *cell = ERR_PTR(-ENOENT);
1314         struct nvmem_cell_lookup *lookup;
1315         struct nvmem_device *nvmem;
1316         const char *dev_id;
1317
1318         if (!dev)
1319                 return ERR_PTR(-EINVAL);
1320
1321         dev_id = dev_name(dev);
1322
1323         mutex_lock(&nvmem_lookup_mutex);
1324
1325         list_for_each_entry(lookup, &nvmem_lookup_list, node) {
1326                 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
1327                     (strcmp(lookup->con_id, con_id) == 0)) {
1328                         /* This is the right entry. */
1329                         nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
1330                                                    device_match_name);
1331                         if (IS_ERR(nvmem)) {
1332                                 /* Provider may not be registered yet. */
1333                                 cell = ERR_CAST(nvmem);
1334                                 break;
1335                         }
1336
1337                         cell_entry = nvmem_find_cell_entry_by_name(nvmem,
1338                                                                    lookup->cell_name);
1339                         if (!cell_entry) {
1340                                 __nvmem_device_put(nvmem);
1341                                 cell = ERR_PTR(-ENOENT);
1342                         } else {
1343                                 cell = nvmem_create_cell(cell_entry, con_id, 0);
1344                                 if (IS_ERR(cell))
1345                                         __nvmem_device_put(nvmem);
1346                         }
1347                         break;
1348                 }
1349         }
1350
1351         mutex_unlock(&nvmem_lookup_mutex);
1352         return cell;
1353 }
1354
1355 #if IS_ENABLED(CONFIG_OF)
1356 static struct nvmem_cell_entry *
1357 nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
1358 {
1359         struct nvmem_cell_entry *iter, *cell = NULL;
1360
1361         mutex_lock(&nvmem_mutex);
1362         list_for_each_entry(iter, &nvmem->cells, node) {
1363                 if (np == iter->np) {
1364                         cell = iter;
1365                         break;
1366                 }
1367         }
1368         mutex_unlock(&nvmem_mutex);
1369
1370         return cell;
1371 }
1372
1373 /**
1374  * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
1375  *
1376  * @np: Device tree node that uses the nvmem cell.
1377  * @id: nvmem cell name from nvmem-cell-names property, or NULL
1378  *      for the cell at index 0 (the lone cell with no accompanying
1379  *      nvmem-cell-names property).
1380  *
1381  * Return: Will be an ERR_PTR() on error or a valid pointer
1382  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1383  * nvmem_cell_put().
1384  */
1385 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
1386 {
1387         struct device_node *cell_np, *nvmem_np;
1388         struct nvmem_device *nvmem;
1389         struct nvmem_cell_entry *cell_entry;
1390         struct nvmem_cell *cell;
1391         struct of_phandle_args cell_spec;
1392         int index = 0;
1393         int cell_index = 0;
1394         int ret;
1395
1396         /* if cell name exists, find index to the name */
1397         if (id)
1398                 index = of_property_match_string(np, "nvmem-cell-names", id);
1399
1400         ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
1401                                                   "#nvmem-cell-cells",
1402                                                   index, &cell_spec);
1403         if (ret)
1404                 return ERR_PTR(-ENOENT);
1405
1406         if (cell_spec.args_count > 1)
1407                 return ERR_PTR(-EINVAL);
1408
1409         cell_np = cell_spec.np;
1410         if (cell_spec.args_count)
1411                 cell_index = cell_spec.args[0];
1412
1413         nvmem_np = of_get_parent(cell_np);
1414         if (!nvmem_np) {
1415                 of_node_put(cell_np);
1416                 return ERR_PTR(-EINVAL);
1417         }
1418
1419         /* nvmem layouts produce cells within the nvmem-layout container */
1420         if (of_node_name_eq(nvmem_np, "nvmem-layout")) {
1421                 nvmem_np = of_get_next_parent(nvmem_np);
1422                 if (!nvmem_np) {
1423                         of_node_put(cell_np);
1424                         return ERR_PTR(-EINVAL);
1425                 }
1426         }
1427
1428         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1429         of_node_put(nvmem_np);
1430         if (IS_ERR(nvmem)) {
1431                 of_node_put(cell_np);
1432                 return ERR_CAST(nvmem);
1433         }
1434
1435         cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
1436         of_node_put(cell_np);
1437         if (!cell_entry) {
1438                 __nvmem_device_put(nvmem);
1439                 return ERR_PTR(-ENOENT);
1440         }
1441
1442         cell = nvmem_create_cell(cell_entry, id, cell_index);
1443         if (IS_ERR(cell))
1444                 __nvmem_device_put(nvmem);
1445
1446         return cell;
1447 }
1448 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
1449 #endif
1450
1451 /**
1452  * nvmem_cell_get() - Get nvmem cell of device form a given cell name
1453  *
1454  * @dev: Device that requests the nvmem cell.
1455  * @id: nvmem cell name to get (this corresponds with the name from the
1456  *      nvmem-cell-names property for DT systems and with the con_id from
1457  *      the lookup entry for non-DT systems).
1458  *
1459  * Return: Will be an ERR_PTR() on error or a valid pointer
1460  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1461  * nvmem_cell_put().
1462  */
1463 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
1464 {
1465         struct nvmem_cell *cell;
1466
1467         if (dev->of_node) { /* try dt first */
1468                 cell = of_nvmem_cell_get(dev->of_node, id);
1469                 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
1470                         return cell;
1471         }
1472
1473         /* NULL cell id only allowed for device tree; invalid otherwise */
1474         if (!id)
1475                 return ERR_PTR(-EINVAL);
1476
1477         return nvmem_cell_get_from_lookup(dev, id);
1478 }
1479 EXPORT_SYMBOL_GPL(nvmem_cell_get);
1480
1481 static void devm_nvmem_cell_release(struct device *dev, void *res)
1482 {
1483         nvmem_cell_put(*(struct nvmem_cell **)res);
1484 }
1485
1486 /**
1487  * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
1488  *
1489  * @dev: Device that requests the nvmem cell.
1490  * @id: nvmem cell name id to get.
1491  *
1492  * Return: Will be an ERR_PTR() on error or a valid pointer
1493  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1494  * automatically once the device is freed.
1495  */
1496 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
1497 {
1498         struct nvmem_cell **ptr, *cell;
1499
1500         ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
1501         if (!ptr)
1502                 return ERR_PTR(-ENOMEM);
1503
1504         cell = nvmem_cell_get(dev, id);
1505         if (!IS_ERR(cell)) {
1506                 *ptr = cell;
1507                 devres_add(dev, ptr);
1508         } else {
1509                 devres_free(ptr);
1510         }
1511
1512         return cell;
1513 }
1514 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
1515
1516 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
1517 {
1518         struct nvmem_cell **c = res;
1519
1520         if (WARN_ON(!c || !*c))
1521                 return 0;
1522
1523         return *c == data;
1524 }
1525
1526 /**
1527  * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1528  * from devm_nvmem_cell_get.
1529  *
1530  * @dev: Device that requests the nvmem cell.
1531  * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1532  */
1533 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1534 {
1535         int ret;
1536
1537         ret = devres_release(dev, devm_nvmem_cell_release,
1538                                 devm_nvmem_cell_match, cell);
1539
1540         WARN_ON(ret);
1541 }
1542 EXPORT_SYMBOL(devm_nvmem_cell_put);
1543
1544 /**
1545  * nvmem_cell_put() - Release previously allocated nvmem cell.
1546  *
1547  * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1548  */
1549 void nvmem_cell_put(struct nvmem_cell *cell)
1550 {
1551         struct nvmem_device *nvmem = cell->entry->nvmem;
1552
1553         if (cell->id)
1554                 kfree_const(cell->id);
1555
1556         kfree(cell);
1557         __nvmem_device_put(nvmem);
1558 }
1559 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1560
1561 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
1562 {
1563         u8 *p, *b;
1564         int i, extra, bit_offset = cell->bit_offset;
1565
1566         p = b = buf;
1567         if (bit_offset) {
1568                 /* First shift */
1569                 *b++ >>= bit_offset;
1570
1571                 /* setup rest of the bytes if any */
1572                 for (i = 1; i < cell->bytes; i++) {
1573                         /* Get bits from next byte and shift them towards msb */
1574                         *p |= *b << (BITS_PER_BYTE - bit_offset);
1575
1576                         p = b;
1577                         *b++ >>= bit_offset;
1578                 }
1579         } else {
1580                 /* point to the msb */
1581                 p += cell->bytes - 1;
1582         }
1583
1584         /* result fits in less bytes */
1585         extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1586         while (--extra >= 0)
1587                 *p-- = 0;
1588
1589         /* clear msb bits if any leftover in the last byte */
1590         if (cell->nbits % BITS_PER_BYTE)
1591                 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1592 }
1593
1594 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1595                              struct nvmem_cell_entry *cell,
1596                              void *buf, size_t *len, const char *id, int index)
1597 {
1598         int rc;
1599
1600         rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len);
1601
1602         if (rc)
1603                 return rc;
1604
1605         /* shift bits in-place */
1606         if (cell->bit_offset || cell->nbits)
1607                 nvmem_shift_read_buffer_in_place(cell, buf);
1608
1609         if (cell->read_post_process) {
1610                 rc = cell->read_post_process(cell->priv, id, index,
1611                                              cell->offset, buf, cell->raw_len);
1612                 if (rc)
1613                         return rc;
1614         }
1615
1616         if (len)
1617                 *len = cell->bytes;
1618
1619         return 0;
1620 }
1621
1622 /**
1623  * nvmem_cell_read() - Read a given nvmem cell
1624  *
1625  * @cell: nvmem cell to be read.
1626  * @len: pointer to length of cell which will be populated on successful read;
1627  *       can be NULL.
1628  *
1629  * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1630  * buffer should be freed by the consumer with a kfree().
1631  */
1632 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1633 {
1634         struct nvmem_cell_entry *entry = cell->entry;
1635         struct nvmem_device *nvmem = entry->nvmem;
1636         u8 *buf;
1637         int rc;
1638
1639         if (!nvmem)
1640                 return ERR_PTR(-EINVAL);
1641
1642         buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL);
1643         if (!buf)
1644                 return ERR_PTR(-ENOMEM);
1645
1646         rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index);
1647         if (rc) {
1648                 kfree(buf);
1649                 return ERR_PTR(rc);
1650         }
1651
1652         return buf;
1653 }
1654 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1655
1656 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
1657                                              u8 *_buf, int len)
1658 {
1659         struct nvmem_device *nvmem = cell->nvmem;
1660         int i, rc, nbits, bit_offset = cell->bit_offset;
1661         u8 v, *p, *buf, *b, pbyte, pbits;
1662
1663         nbits = cell->nbits;
1664         buf = kzalloc(cell->bytes, GFP_KERNEL);
1665         if (!buf)
1666                 return ERR_PTR(-ENOMEM);
1667
1668         memcpy(buf, _buf, len);
1669         p = b = buf;
1670
1671         if (bit_offset) {
1672                 pbyte = *b;
1673                 *b <<= bit_offset;
1674
1675                 /* setup the first byte with lsb bits from nvmem */
1676                 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1677                 if (rc)
1678                         goto err;
1679                 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1680
1681                 /* setup rest of the byte if any */
1682                 for (i = 1; i < cell->bytes; i++) {
1683                         /* Get last byte bits and shift them towards lsb */
1684                         pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1685                         pbyte = *b;
1686                         p = b;
1687                         *b <<= bit_offset;
1688                         *b++ |= pbits;
1689                 }
1690         }
1691
1692         /* if it's not end on byte boundary */
1693         if ((nbits + bit_offset) % BITS_PER_BYTE) {
1694                 /* setup the last byte with msb bits from nvmem */
1695                 rc = nvmem_reg_read(nvmem,
1696                                     cell->offset + cell->bytes - 1, &v, 1);
1697                 if (rc)
1698                         goto err;
1699                 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1700
1701         }
1702
1703         return buf;
1704 err:
1705         kfree(buf);
1706         return ERR_PTR(rc);
1707 }
1708
1709 static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
1710 {
1711         struct nvmem_device *nvmem = cell->nvmem;
1712         int rc;
1713
1714         if (!nvmem || nvmem->read_only ||
1715             (cell->bit_offset == 0 && len != cell->bytes))
1716                 return -EINVAL;
1717
1718         /*
1719          * Any cells which have a read_post_process hook are read-only because
1720          * we cannot reverse the operation and it might affect other cells,
1721          * too.
1722          */
1723         if (cell->read_post_process)
1724                 return -EINVAL;
1725
1726         if (cell->bit_offset || cell->nbits) {
1727                 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1728                 if (IS_ERR(buf))
1729                         return PTR_ERR(buf);
1730         }
1731
1732         rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1733
1734         /* free the tmp buffer */
1735         if (cell->bit_offset || cell->nbits)
1736                 kfree(buf);
1737
1738         if (rc)
1739                 return rc;
1740
1741         return len;
1742 }
1743
1744 /**
1745  * nvmem_cell_write() - Write to a given nvmem cell
1746  *
1747  * @cell: nvmem cell to be written.
1748  * @buf: Buffer to be written.
1749  * @len: length of buffer to be written to nvmem cell.
1750  *
1751  * Return: length of bytes written or negative on failure.
1752  */
1753 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1754 {
1755         return __nvmem_cell_entry_write(cell->entry, buf, len);
1756 }
1757
1758 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1759
1760 static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
1761                                   void *val, size_t count)
1762 {
1763         struct nvmem_cell *cell;
1764         void *buf;
1765         size_t len;
1766
1767         cell = nvmem_cell_get(dev, cell_id);
1768         if (IS_ERR(cell))
1769                 return PTR_ERR(cell);
1770
1771         buf = nvmem_cell_read(cell, &len);
1772         if (IS_ERR(buf)) {
1773                 nvmem_cell_put(cell);
1774                 return PTR_ERR(buf);
1775         }
1776         if (len != count) {
1777                 kfree(buf);
1778                 nvmem_cell_put(cell);
1779                 return -EINVAL;
1780         }
1781         memcpy(val, buf, count);
1782         kfree(buf);
1783         nvmem_cell_put(cell);
1784
1785         return 0;
1786 }
1787
1788 /**
1789  * nvmem_cell_read_u8() - Read a cell value as a u8
1790  *
1791  * @dev: Device that requests the nvmem cell.
1792  * @cell_id: Name of nvmem cell to read.
1793  * @val: pointer to output value.
1794  *
1795  * Return: 0 on success or negative errno.
1796  */
1797 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
1798 {
1799         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1800 }
1801 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);
1802
1803 /**
1804  * nvmem_cell_read_u16() - Read a cell value as a u16
1805  *
1806  * @dev: Device that requests the nvmem cell.
1807  * @cell_id: Name of nvmem cell to read.
1808  * @val: pointer to output value.
1809  *
1810  * Return: 0 on success or negative errno.
1811  */
1812 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1813 {
1814         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1815 }
1816 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1817
1818 /**
1819  * nvmem_cell_read_u32() - Read a cell value as a u32
1820  *
1821  * @dev: Device that requests the nvmem cell.
1822  * @cell_id: Name of nvmem cell to read.
1823  * @val: pointer to output value.
1824  *
1825  * Return: 0 on success or negative errno.
1826  */
1827 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1828 {
1829         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1830 }
1831 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1832
1833 /**
1834  * nvmem_cell_read_u64() - Read a cell value as a u64
1835  *
1836  * @dev: Device that requests the nvmem cell.
1837  * @cell_id: Name of nvmem cell to read.
1838  * @val: pointer to output value.
1839  *
1840  * Return: 0 on success or negative errno.
1841  */
1842 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
1843 {
1844         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1845 }
1846 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);
1847
1848 static const void *nvmem_cell_read_variable_common(struct device *dev,
1849                                                    const char *cell_id,
1850                                                    size_t max_len, size_t *len)
1851 {
1852         struct nvmem_cell *cell;
1853         int nbits;
1854         void *buf;
1855
1856         cell = nvmem_cell_get(dev, cell_id);
1857         if (IS_ERR(cell))
1858                 return cell;
1859
1860         nbits = cell->entry->nbits;
1861         buf = nvmem_cell_read(cell, len);
1862         nvmem_cell_put(cell);
1863         if (IS_ERR(buf))
1864                 return buf;
1865
1866         /*
1867          * If nbits is set then nvmem_cell_read() can significantly exaggerate
1868          * the length of the real data. Throw away the extra junk.
1869          */
1870         if (nbits)
1871                 *len = DIV_ROUND_UP(nbits, 8);
1872
1873         if (*len > max_len) {
1874                 kfree(buf);
1875                 return ERR_PTR(-ERANGE);
1876         }
1877
1878         return buf;
1879 }
1880
1881 /**
1882  * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
1883  *
1884  * @dev: Device that requests the nvmem cell.
1885  * @cell_id: Name of nvmem cell to read.
1886  * @val: pointer to output value.
1887  *
1888  * Return: 0 on success or negative errno.
1889  */
1890 int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
1891                                     u32 *val)
1892 {
1893         size_t len;
1894         const u8 *buf;
1895         int i;
1896
1897         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1898         if (IS_ERR(buf))
1899                 return PTR_ERR(buf);
1900
1901         /* Copy w/ implicit endian conversion */
1902         *val = 0;
1903         for (i = 0; i < len; i++)
1904                 *val |= buf[i] << (8 * i);
1905
1906         kfree(buf);
1907
1908         return 0;
1909 }
1910 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);
1911
1912 /**
1913  * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
1914  *
1915  * @dev: Device that requests the nvmem cell.
1916  * @cell_id: Name of nvmem cell to read.
1917  * @val: pointer to output value.
1918  *
1919  * Return: 0 on success or negative errno.
1920  */
1921 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
1922                                     u64 *val)
1923 {
1924         size_t len;
1925         const u8 *buf;
1926         int i;
1927
1928         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1929         if (IS_ERR(buf))
1930                 return PTR_ERR(buf);
1931
1932         /* Copy w/ implicit endian conversion */
1933         *val = 0;
1934         for (i = 0; i < len; i++)
1935                 *val |= (uint64_t)buf[i] << (8 * i);
1936
1937         kfree(buf);
1938
1939         return 0;
1940 }
1941 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);
1942
1943 /**
1944  * nvmem_device_cell_read() - Read a given nvmem device and cell
1945  *
1946  * @nvmem: nvmem device to read from.
1947  * @info: nvmem cell info to be read.
1948  * @buf: buffer pointer which will be populated on successful read.
1949  *
1950  * Return: length of successful bytes read on success and negative
1951  * error code on error.
1952  */
1953 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1954                            struct nvmem_cell_info *info, void *buf)
1955 {
1956         struct nvmem_cell_entry cell;
1957         int rc;
1958         ssize_t len;
1959
1960         if (!nvmem)
1961                 return -EINVAL;
1962
1963         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1964         if (rc)
1965                 return rc;
1966
1967         rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0);
1968         if (rc)
1969                 return rc;
1970
1971         return len;
1972 }
1973 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1974
1975 /**
1976  * nvmem_device_cell_write() - Write cell to a given nvmem device
1977  *
1978  * @nvmem: nvmem device to be written to.
1979  * @info: nvmem cell info to be written.
1980  * @buf: buffer to be written to cell.
1981  *
1982  * Return: length of bytes written or negative error code on failure.
1983  */
1984 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1985                             struct nvmem_cell_info *info, void *buf)
1986 {
1987         struct nvmem_cell_entry cell;
1988         int rc;
1989
1990         if (!nvmem)
1991                 return -EINVAL;
1992
1993         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1994         if (rc)
1995                 return rc;
1996
1997         return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
1998 }
1999 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
2000
2001 /**
2002  * nvmem_device_read() - Read from a given nvmem device
2003  *
2004  * @nvmem: nvmem device to read from.
2005  * @offset: offset in nvmem device.
2006  * @bytes: number of bytes to read.
2007  * @buf: buffer pointer which will be populated on successful read.
2008  *
2009  * Return: length of successful bytes read on success and negative
2010  * error code on error.
2011  */
2012 int nvmem_device_read(struct nvmem_device *nvmem,
2013                       unsigned int offset,
2014                       size_t bytes, void *buf)
2015 {
2016         int rc;
2017
2018         if (!nvmem)
2019                 return -EINVAL;
2020
2021         rc = nvmem_reg_read(nvmem, offset, buf, bytes);
2022
2023         if (rc)
2024                 return rc;
2025
2026         return bytes;
2027 }
2028 EXPORT_SYMBOL_GPL(nvmem_device_read);
2029
2030 /**
2031  * nvmem_device_write() - Write cell to a given nvmem device
2032  *
2033  * @nvmem: nvmem device to be written to.
2034  * @offset: offset in nvmem device.
2035  * @bytes: number of bytes to write.
2036  * @buf: buffer to be written.
2037  *
2038  * Return: length of bytes written or negative error code on failure.
2039  */
2040 int nvmem_device_write(struct nvmem_device *nvmem,
2041                        unsigned int offset,
2042                        size_t bytes, void *buf)
2043 {
2044         int rc;
2045
2046         if (!nvmem)
2047                 return -EINVAL;
2048
2049         rc = nvmem_reg_write(nvmem, offset, buf, bytes);
2050
2051         if (rc)
2052                 return rc;
2053
2054
2055         return bytes;
2056 }
2057 EXPORT_SYMBOL_GPL(nvmem_device_write);
2058
2059 /**
2060  * nvmem_add_cell_table() - register a table of cell info entries
2061  *
2062  * @table: table of cell info entries
2063  */
2064 void nvmem_add_cell_table(struct nvmem_cell_table *table)
2065 {
2066         mutex_lock(&nvmem_cell_mutex);
2067         list_add_tail(&table->node, &nvmem_cell_tables);
2068         mutex_unlock(&nvmem_cell_mutex);
2069 }
2070 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
2071
2072 /**
2073  * nvmem_del_cell_table() - remove a previously registered cell info table
2074  *
2075  * @table: table of cell info entries
2076  */
2077 void nvmem_del_cell_table(struct nvmem_cell_table *table)
2078 {
2079         mutex_lock(&nvmem_cell_mutex);
2080         list_del(&table->node);
2081         mutex_unlock(&nvmem_cell_mutex);
2082 }
2083 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
2084
2085 /**
2086  * nvmem_add_cell_lookups() - register a list of cell lookup entries
2087  *
2088  * @entries: array of cell lookup entries
2089  * @nentries: number of cell lookup entries in the array
2090  */
2091 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2092 {
2093         int i;
2094
2095         mutex_lock(&nvmem_lookup_mutex);
2096         for (i = 0; i < nentries; i++)
2097                 list_add_tail(&entries[i].node, &nvmem_lookup_list);
2098         mutex_unlock(&nvmem_lookup_mutex);
2099 }
2100 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
2101
2102 /**
2103  * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
2104  *                            entries
2105  *
2106  * @entries: array of cell lookup entries
2107  * @nentries: number of cell lookup entries in the array
2108  */
2109 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2110 {
2111         int i;
2112
2113         mutex_lock(&nvmem_lookup_mutex);
2114         for (i = 0; i < nentries; i++)
2115                 list_del(&entries[i].node);
2116         mutex_unlock(&nvmem_lookup_mutex);
2117 }
2118 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
2119
2120 /**
2121  * nvmem_dev_name() - Get the name of a given nvmem device.
2122  *
2123  * @nvmem: nvmem device.
2124  *
2125  * Return: name of the nvmem device.
2126  */
2127 const char *nvmem_dev_name(struct nvmem_device *nvmem)
2128 {
2129         return dev_name(&nvmem->dev);
2130 }
2131 EXPORT_SYMBOL_GPL(nvmem_dev_name);
2132
2133 static int __init nvmem_init(void)
2134 {
2135         return bus_register(&nvmem_bus_type);
2136 }
2137
2138 static void __exit nvmem_exit(void)
2139 {
2140         bus_unregister(&nvmem_bus_type);
2141 }
2142
2143 subsys_initcall(nvmem_init);
2144 module_exit(nvmem_exit);
2145
2146 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
2147 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
2148 MODULE_DESCRIPTION("nvmem Driver Core");