drivers/nvmem/core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * nvmem framework core.
   4  *
   5  * Copyright (C) 2015 Srinivas Kandagatla <[email protected]>
   6  * Copyright (C) 2013 Maxime Ripard <[email protected]>
   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
 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         if (config->add_legacy_fixed_of_cells) {
1007                 rval = nvmem_add_cells_from_legacy_of(nvmem);
1008                 if (rval)
1009                         goto err_remove_cells;
1010         }
1011
1012         rval = nvmem_add_cells_from_fixed_layout(nvmem);
1013         if (rval)
1014                 goto err_remove_cells;
1015
1016         rval = nvmem_add_cells_from_layout(nvmem);
1017         if (rval)
1018                 goto err_remove_cells;
1019
1020         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
1021
1022         rval = device_add(&nvmem->dev);
1023         if (rval)
1024                 goto err_remove_cells;
1025
1026         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
1027
1028         return nvmem;
1029
1030 err_remove_cells:
1031         nvmem_device_remove_all_cells(nvmem);
1032         nvmem_layout_put(nvmem->layout);
1033 err_teardown_compat:
1034         if (config->compat)
1035                 nvmem_sysfs_remove_compat(nvmem, config);
1036 err_put_device:
1037         put_device(&nvmem->dev);
1038
1039         return ERR_PTR(rval);
1040 }
1041 EXPORT_SYMBOL_GPL(nvmem_register);
1042
1043 static void nvmem_device_release(struct kref *kref)
1044 {
1045         struct nvmem_device *nvmem;
1046
1047         nvmem = container_of(kref, struct nvmem_device, refcnt);
1048
1049         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
1050
1051         if (nvmem->flags & FLAG_COMPAT)
1052                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
1053
1054         nvmem_device_remove_all_cells(nvmem);
1055         nvmem_layout_put(nvmem->layout);
1056         device_unregister(&nvmem->dev);
1057 }
1058
1059 /**
1060  * nvmem_unregister() - Unregister previously registered nvmem device
1061  *
1062  * @nvmem: Pointer to previously registered nvmem device.
1063  */
1064 void nvmem_unregister(struct nvmem_device *nvmem)
1065 {
1066         if (nvmem)
1067                 kref_put(&nvmem->refcnt, nvmem_device_release);
1068 }
1069 EXPORT_SYMBOL_GPL(nvmem_unregister);
1070
1071 static void devm_nvmem_unregister(void *nvmem)
1072 {
1073         nvmem_unregister(nvmem);
1074 }
1075
1076 /**
1077  * devm_nvmem_register() - Register a managed nvmem device for given
1078  * nvmem_config.
1079  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
1080  *
1081  * @dev: Device that uses the nvmem device.
1082  * @config: nvmem device configuration with which nvmem device is created.
1083  *
1084  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
1085  * on success.
1086  */
1087 struct nvmem_device *devm_nvmem_register(struct device *dev,
1088                                          const struct nvmem_config *config)
1089 {
1090         struct nvmem_device *nvmem;
1091         int ret;
1092
1093         nvmem = nvmem_register(config);
1094         if (IS_ERR(nvmem))
1095                 return nvmem;
1096
1097         ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem);
1098         if (ret)
1099                 return ERR_PTR(ret);
1100
1101         return nvmem;
1102 }
1103 EXPORT_SYMBOL_GPL(devm_nvmem_register);
1104
1105 static struct nvmem_device *__nvmem_device_get(void *data,
1106                         int (*match)(struct device *dev, const void *data))
1107 {
1108         struct nvmem_device *nvmem = NULL;
1109         struct device *dev;
1110
1111         mutex_lock(&nvmem_mutex);
1112         dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
1113         if (dev)
1114                 nvmem = to_nvmem_device(dev);
1115         mutex_unlock(&nvmem_mutex);
1116         if (!nvmem)
1117                 return ERR_PTR(-EPROBE_DEFER);
1118
1119         if (!try_module_get(nvmem->owner)) {
1120                 dev_err(&nvmem->dev,
1121                         "could not increase module refcount for cell %s\n",
1122                         nvmem_dev_name(nvmem));
1123
1124                 put_device(&nvmem->dev);
1125                 return ERR_PTR(-EINVAL);
1126         }
1127
1128         kref_get(&nvmem->refcnt);
1129
1130         return nvmem;
1131 }
1132
1133 static void __nvmem_device_put(struct nvmem_device *nvmem)
1134 {
1135         put_device(&nvmem->dev);
1136         module_put(nvmem->owner);
1137         kref_put(&nvmem->refcnt, nvmem_device_release);
1138 }
1139
1140 #if IS_ENABLED(CONFIG_OF)
1141 /**
1142  * of_nvmem_device_get() - Get nvmem device from a given id
1143  *
1144  * @np: Device tree node that uses the nvmem device.
1145  * @id: nvmem name from nvmem-names property.
1146  *
1147  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1148  * on success.
1149  */
1150 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
1151 {
1152
1153         struct device_node *nvmem_np;
1154         struct nvmem_device *nvmem;
1155         int index = 0;
1156
1157         if (id)
1158                 index = of_property_match_string(np, "nvmem-names", id);
1159
1160         nvmem_np = of_parse_phandle(np, "nvmem", index);
1161         if (!nvmem_np)
1162                 return ERR_PTR(-ENOENT);
1163
1164         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1165         of_node_put(nvmem_np);
1166         return nvmem;
1167 }
1168 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
1169 #endif
1170
1171 /**
1172  * nvmem_device_get() - Get nvmem device from a given id
1173  *
1174  * @dev: Device that uses the nvmem device.
1175  * @dev_name: name of the requested nvmem device.
1176  *
1177  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1178  * on success.
1179  */
1180 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
1181 {
1182         if (dev->of_node) { /* try dt first */
1183                 struct nvmem_device *nvmem;
1184
1185                 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
1186
1187                 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
1188                         return nvmem;
1189
1190         }
1191
1192         return __nvmem_device_get((void *)dev_name, device_match_name);
1193 }
1194 EXPORT_SYMBOL_GPL(nvmem_device_get);
1195
1196 /**
1197  * nvmem_device_find() - Find nvmem device with matching function
1198  *
1199  * @data: Data to pass to match function
1200  * @match: Callback function to check device
1201  *
1202  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1203  * on success.
1204  */
1205 struct nvmem_device *nvmem_device_find(void *data,
1206                         int (*match)(struct device *dev, const void *data))
1207 {
1208         return __nvmem_device_get(data, match);
1209 }
1210 EXPORT_SYMBOL_GPL(nvmem_device_find);
1211
1212 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
1213 {
1214         struct nvmem_device **nvmem = res;
1215
1216         if (WARN_ON(!nvmem || !*nvmem))
1217                 return 0;
1218
1219         return *nvmem == data;
1220 }
1221
1222 static void devm_nvmem_device_release(struct device *dev, void *res)
1223 {
1224         nvmem_device_put(*(struct nvmem_device **)res);
1225 }
1226
1227 /**
1228  * devm_nvmem_device_put() - put alredy got nvmem device
1229  *
1230  * @dev: Device that uses the nvmem device.
1231  * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
1232  * that needs to be released.
1233  */
1234 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
1235 {
1236         int ret;
1237
1238         ret = devres_release(dev, devm_nvmem_device_release,
1239                              devm_nvmem_device_match, nvmem);
1240
1241         WARN_ON(ret);
1242 }
1243 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
1244
1245 /**
1246  * nvmem_device_put() - put alredy got nvmem device
1247  *
1248  * @nvmem: pointer to nvmem device that needs to be released.
1249  */
1250 void nvmem_device_put(struct nvmem_device *nvmem)
1251 {
1252         __nvmem_device_put(nvmem);
1253 }
1254 EXPORT_SYMBOL_GPL(nvmem_device_put);
1255
1256 /**
1257  * devm_nvmem_device_get() - Get nvmem cell of device form a given id
1258  *
1259  * @dev: Device that requests the nvmem device.
1260  * @id: name id for the requested nvmem device.
1261  *
1262  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
1263  * on success.  The nvmem_cell will be freed by the automatically once the
1264  * device is freed.
1265  */
1266 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
1267 {
1268         struct nvmem_device **ptr, *nvmem;
1269
1270         ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
1271         if (!ptr)
1272                 return ERR_PTR(-ENOMEM);
1273
1274         nvmem = nvmem_device_get(dev, id);
1275         if (!IS_ERR(nvmem)) {
1276                 *ptr = nvmem;
1277                 devres_add(dev, ptr);
1278         } else {
1279                 devres_free(ptr);
1280         }
1281
1282         return nvmem;
1283 }
1284 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
1285
1286 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
1287                                             const char *id, int index)
1288 {
1289         struct nvmem_cell *cell;
1290         const char *name = NULL;
1291
1292         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
1293         if (!cell)
1294                 return ERR_PTR(-ENOMEM);
1295
1296         if (id) {
1297                 name = kstrdup_const(id, GFP_KERNEL);
1298                 if (!name) {
1299                         kfree(cell);
1300                         return ERR_PTR(-ENOMEM);
1301                 }
1302         }
1303
1304         cell->id = name;
1305         cell->entry = entry;
1306         cell->index = index;
1307
1308         return cell;
1309 }
1310
1311 static struct nvmem_cell *
1312 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
1313 {
1314         struct nvmem_cell_entry *cell_entry;
1315         struct nvmem_cell *cell = ERR_PTR(-ENOENT);
1316         struct nvmem_cell_lookup *lookup;
1317         struct nvmem_device *nvmem;
1318         const char *dev_id;
1319
1320         if (!dev)
1321                 return ERR_PTR(-EINVAL);
1322
1323         dev_id = dev_name(dev);
1324
1325         mutex_lock(&nvmem_lookup_mutex);
1326
1327         list_for_each_entry(lookup, &nvmem_lookup_list, node) {
1328                 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
1329                     (strcmp(lookup->con_id, con_id) == 0)) {
1330                         /* This is the right entry. */
1331                         nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
1332                                                    device_match_name);
1333                         if (IS_ERR(nvmem)) {
1334                                 /* Provider may not be registered yet. */
1335                                 cell = ERR_CAST(nvmem);
1336                                 break;
1337                         }
1338
1339                         cell_entry = nvmem_find_cell_entry_by_name(nvmem,
1340                                                                    lookup->cell_name);
1341                         if (!cell_entry) {
1342                                 __nvmem_device_put(nvmem);
1343                                 cell = ERR_PTR(-ENOENT);
1344                         } else {
1345                                 cell = nvmem_create_cell(cell_entry, con_id, 0);
1346                                 if (IS_ERR(cell))
1347                                         __nvmem_device_put(nvmem);
1348                         }
1349                         break;
1350                 }
1351         }
1352
1353         mutex_unlock(&nvmem_lookup_mutex);
1354         return cell;
1355 }
1356
1357 #if IS_ENABLED(CONFIG_OF)
1358 static struct nvmem_cell_entry *
1359 nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
1360 {
1361         struct nvmem_cell_entry *iter, *cell = NULL;
1362
1363         mutex_lock(&nvmem_mutex);
1364         list_for_each_entry(iter, &nvmem->cells, node) {
1365                 if (np == iter->np) {
1366                         cell = iter;
1367                         break;
1368                 }
1369         }
1370         mutex_unlock(&nvmem_mutex);
1371
1372         return cell;
1373 }
1374
1375 /**
1376  * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
1377  *
1378  * @np: Device tree node that uses the nvmem cell.
1379  * @id: nvmem cell name from nvmem-cell-names property, or NULL
1380  *      for the cell at index 0 (the lone cell with no accompanying
1381  *      nvmem-cell-names property).
1382  *
1383  * Return: Will be an ERR_PTR() on error or a valid pointer
1384  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1385  * nvmem_cell_put().
1386  */
1387 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
1388 {
1389         struct device_node *cell_np, *nvmem_np;
1390         struct nvmem_device *nvmem;
1391         struct nvmem_cell_entry *cell_entry;
1392         struct nvmem_cell *cell;
1393         struct of_phandle_args cell_spec;
1394         int index = 0;
1395         int cell_index = 0;
1396         int ret;
1397
1398         /* if cell name exists, find index to the name */
1399         if (id)
1400                 index = of_property_match_string(np, "nvmem-cell-names", id);
1401
1402         ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
1403                                                   "#nvmem-cell-cells",
1404                                                   index, &cell_spec);
1405         if (ret)
1406                 return ERR_PTR(-ENOENT);
1407
1408         if (cell_spec.args_count > 1)
1409                 return ERR_PTR(-EINVAL);
1410
1411         cell_np = cell_spec.np;
1412         if (cell_spec.args_count)
1413                 cell_index = cell_spec.args[0];
1414
1415         nvmem_np = of_get_parent(cell_np);
1416         if (!nvmem_np) {
1417                 of_node_put(cell_np);
1418                 return ERR_PTR(-EINVAL);
1419         }
1420
1421         /* nvmem layouts produce cells within the nvmem-layout container */
1422         if (of_node_name_eq(nvmem_np, "nvmem-layout")) {
1423                 nvmem_np = of_get_next_parent(nvmem_np);
1424                 if (!nvmem_np) {
1425                         of_node_put(cell_np);
1426                         return ERR_PTR(-EINVAL);
1427                 }
1428         }
1429
1430         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1431         of_node_put(nvmem_np);
1432         if (IS_ERR(nvmem)) {
1433                 of_node_put(cell_np);
1434                 return ERR_CAST(nvmem);
1435         }
1436
1437         cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
1438         of_node_put(cell_np);
1439         if (!cell_entry) {
1440                 __nvmem_device_put(nvmem);
1441                 return ERR_PTR(-ENOENT);
1442         }
1443
1444         cell = nvmem_create_cell(cell_entry, id, cell_index);
1445         if (IS_ERR(cell))
1446                 __nvmem_device_put(nvmem);
1447
1448         return cell;
1449 }
1450 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
1451 #endif
1452
1453 /**
1454  * nvmem_cell_get() - Get nvmem cell of device form a given cell name
1455  *
1456  * @dev: Device that requests the nvmem cell.
1457  * @id: nvmem cell name to get (this corresponds with the name from the
1458  *      nvmem-cell-names property for DT systems and with the con_id from
1459  *      the lookup entry for non-DT systems).
1460  *
1461  * Return: Will be an ERR_PTR() on error or a valid pointer
1462  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1463  * nvmem_cell_put().
1464  */
1465 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
1466 {
1467         struct nvmem_cell *cell;
1468
1469         if (dev->of_node) { /* try dt first */
1470                 cell = of_nvmem_cell_get(dev->of_node, id);
1471                 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
1472                         return cell;
1473         }
1474
1475         /* NULL cell id only allowed for device tree; invalid otherwise */
1476         if (!id)
1477                 return ERR_PTR(-EINVAL);
1478
1479         return nvmem_cell_get_from_lookup(dev, id);
1480 }
1481 EXPORT_SYMBOL_GPL(nvmem_cell_get);
1482
1483 static void devm_nvmem_cell_release(struct device *dev, void *res)
1484 {
1485         nvmem_cell_put(*(struct nvmem_cell **)res);
1486 }
1487
1488 /**
1489  * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
1490  *
1491  * @dev: Device that requests the nvmem cell.
1492  * @id: nvmem cell name id to get.
1493  *
1494  * Return: Will be an ERR_PTR() on error or a valid pointer
1495  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1496  * automatically once the device is freed.
1497  */
1498 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
1499 {
1500         struct nvmem_cell **ptr, *cell;
1501
1502         ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
1503         if (!ptr)
1504                 return ERR_PTR(-ENOMEM);
1505
1506         cell = nvmem_cell_get(dev, id);
1507         if (!IS_ERR(cell)) {
1508                 *ptr = cell;
1509                 devres_add(dev, ptr);
1510         } else {
1511                 devres_free(ptr);
1512         }
1513
1514         return cell;
1515 }
1516 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
1517
1518 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
1519 {
1520         struct nvmem_cell **c = res;
1521
1522         if (WARN_ON(!c || !*c))
1523                 return 0;
1524
1525         return *c == data;
1526 }
1527
1528 /**
1529  * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1530  * from devm_nvmem_cell_get.
1531  *
1532  * @dev: Device that requests the nvmem cell.
1533  * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1534  */
1535 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1536 {
1537         int ret;
1538
1539         ret = devres_release(dev, devm_nvmem_cell_release,
1540                                 devm_nvmem_cell_match, cell);
1541
1542         WARN_ON(ret);
1543 }
1544 EXPORT_SYMBOL(devm_nvmem_cell_put);
1545
1546 /**
1547  * nvmem_cell_put() - Release previously allocated nvmem cell.
1548  *
1549  * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1550  */
1551 void nvmem_cell_put(struct nvmem_cell *cell)
1552 {
1553         struct nvmem_device *nvmem = cell->entry->nvmem;
1554
1555         if (cell->id)
1556                 kfree_const(cell->id);
1557
1558         kfree(cell);
1559         __nvmem_device_put(nvmem);
1560 }
1561 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1562
1563 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
1564 {
1565         u8 *p, *b;
1566         int i, extra, bit_offset = cell->bit_offset;
1567
1568         p = b = buf;
1569         if (bit_offset) {
1570                 /* First shift */
1571                 *b++ >>= bit_offset;
1572
1573                 /* setup rest of the bytes if any */
1574                 for (i = 1; i < cell->bytes; i++) {
1575                         /* Get bits from next byte and shift them towards msb */
1576                         *p |= *b << (BITS_PER_BYTE - bit_offset);
1577
1578                         p = b;
1579                         *b++ >>= bit_offset;
1580                 }
1581         } else {
1582                 /* point to the msb */
1583                 p += cell->bytes - 1;
1584         }
1585
1586         /* result fits in less bytes */
1587         extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1588         while (--extra >= 0)
1589                 *p-- = 0;
1590
1591         /* clear msb bits if any leftover in the last byte */
1592         if (cell->nbits % BITS_PER_BYTE)
1593                 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1594 }
1595
1596 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1597                              struct nvmem_cell_entry *cell,
1598                              void *buf, size_t *len, const char *id, int index)
1599 {
1600         int rc;
1601
1602         rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len);
1603
1604         if (rc)
1605                 return rc;
1606
1607         /* shift bits in-place */
1608         if (cell->bit_offset || cell->nbits)
1609                 nvmem_shift_read_buffer_in_place(cell, buf);
1610
1611         if (cell->read_post_process) {
1612                 rc = cell->read_post_process(cell->priv, id, index,
1613                                              cell->offset, buf, cell->raw_len);
1614                 if (rc)
1615                         return rc;
1616         }
1617
1618         if (len)
1619                 *len = cell->bytes;
1620
1621         return 0;
1622 }
1623
1624 /**
1625  * nvmem_cell_read() - Read a given nvmem cell
1626  *
1627  * @cell: nvmem cell to be read.
1628  * @len: pointer to length of cell which will be populated on successful read;
1629  *       can be NULL.
1630  *
1631  * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1632  * buffer should be freed by the consumer with a kfree().
1633  */
1634 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1635 {
1636         struct nvmem_cell_entry *entry = cell->entry;
1637         struct nvmem_device *nvmem = entry->nvmem;
1638         u8 *buf;
1639         int rc;
1640
1641         if (!nvmem)
1642                 return ERR_PTR(-EINVAL);
1643
1644         buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL);
1645         if (!buf)
1646                 return ERR_PTR(-ENOMEM);
1647
1648         rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index);
1649         if (rc) {
1650                 kfree(buf);
1651                 return ERR_PTR(rc);
1652         }
1653
1654         return buf;
1655 }
1656 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1657
1658 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
1659                                              u8 *_buf, int len)
1660 {
1661         struct nvmem_device *nvmem = cell->nvmem;
1662         int i, rc, nbits, bit_offset = cell->bit_offset;
1663         u8 v, *p, *buf, *b, pbyte, pbits;
1664
1665         nbits = cell->nbits;
1666         buf = kzalloc(cell->bytes, GFP_KERNEL);
1667         if (!buf)
1668                 return ERR_PTR(-ENOMEM);
1669
1670         memcpy(buf, _buf, len);
1671         p = b = buf;
1672
1673         if (bit_offset) {
1674                 pbyte = *b;
1675                 *b <<= bit_offset;
1676
1677                 /* setup the first byte with lsb bits from nvmem */
1678                 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1679                 if (rc)
1680                         goto err;
1681                 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1682
1683                 /* setup rest of the byte if any */
1684                 for (i = 1; i < cell->bytes; i++) {
1685                         /* Get last byte bits and shift them towards lsb */
1686                         pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1687                         pbyte = *b;
1688                         p = b;
1689                         *b <<= bit_offset;
1690                         *b++ |= pbits;
1691                 }
1692         }
1693
1694         /* if it's not end on byte boundary */
1695         if ((nbits + bit_offset) % BITS_PER_BYTE) {
1696                 /* setup the last byte with msb bits from nvmem */
1697                 rc = nvmem_reg_read(nvmem,
1698                                     cell->offset + cell->bytes - 1, &v, 1);
1699                 if (rc)
1700                         goto err;
1701                 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1702
1703         }
1704
1705         return buf;
1706 err:
1707         kfree(buf);
1708         return ERR_PTR(rc);
1709 }
1710
1711 static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
1712 {
1713         struct nvmem_device *nvmem = cell->nvmem;
1714         int rc;
1715
1716         if (!nvmem || nvmem->read_only ||
1717             (cell->bit_offset == 0 && len != cell->bytes))
1718                 return -EINVAL;
1719
1720         /*
1721          * Any cells which have a read_post_process hook are read-only because
1722          * we cannot reverse the operation and it might affect other cells,
1723          * too.
1724          */
1725         if (cell->read_post_process)
1726                 return -EINVAL;
1727
1728         if (cell->bit_offset || cell->nbits) {
1729                 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1730                 if (IS_ERR(buf))
1731                         return PTR_ERR(buf);
1732         }
1733
1734         rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1735
1736         /* free the tmp buffer */
1737         if (cell->bit_offset || cell->nbits)
1738                 kfree(buf);
1739
1740         if (rc)
1741                 return rc;
1742
1743         return len;
1744 }
1745
1746 /**
1747  * nvmem_cell_write() - Write to a given nvmem cell
1748  *
1749  * @cell: nvmem cell to be written.
1750  * @buf: Buffer to be written.
1751  * @len: length of buffer to be written to nvmem cell.
1752  *
1753  * Return: length of bytes written or negative on failure.
1754  */
1755 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1756 {
1757         return __nvmem_cell_entry_write(cell->entry, buf, len);
1758 }
1759
1760 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1761
1762 static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
1763                                   void *val, size_t count)
1764 {
1765         struct nvmem_cell *cell;
1766         void *buf;
1767         size_t len;
1768
1769         cell = nvmem_cell_get(dev, cell_id);
1770         if (IS_ERR(cell))
1771                 return PTR_ERR(cell);
1772
1773         buf = nvmem_cell_read(cell, &len);
1774         if (IS_ERR(buf)) {
1775                 nvmem_cell_put(cell);
1776                 return PTR_ERR(buf);
1777         }
1778         if (len != count) {
1779                 kfree(buf);
1780                 nvmem_cell_put(cell);
1781                 return -EINVAL;
1782         }
1783         memcpy(val, buf, count);
1784         kfree(buf);
1785         nvmem_cell_put(cell);
1786
1787         return 0;
1788 }
1789
1790 /**
1791  * nvmem_cell_read_u8() - Read a cell value as a u8
1792  *
1793  * @dev: Device that requests the nvmem cell.
1794  * @cell_id: Name of nvmem cell to read.
1795  * @val: pointer to output value.
1796  *
1797  * Return: 0 on success or negative errno.
1798  */
1799 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
1800 {
1801         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1802 }
1803 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);
1804
1805 /**
1806  * nvmem_cell_read_u16() - Read a cell value as a u16
1807  *
1808  * @dev: Device that requests the nvmem cell.
1809  * @cell_id: Name of nvmem cell to read.
1810  * @val: pointer to output value.
1811  *
1812  * Return: 0 on success or negative errno.
1813  */
1814 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1815 {
1816         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1817 }
1818 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1819
1820 /**
1821  * nvmem_cell_read_u32() - Read a cell value as a u32
1822  *
1823  * @dev: Device that requests the nvmem cell.
1824  * @cell_id: Name of nvmem cell to read.
1825  * @val: pointer to output value.
1826  *
1827  * Return: 0 on success or negative errno.
1828  */
1829 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1830 {
1831         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1832 }
1833 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1834
1835 /**
1836  * nvmem_cell_read_u64() - Read a cell value as a u64
1837  *
1838  * @dev: Device that requests the nvmem cell.
1839  * @cell_id: Name of nvmem cell to read.
1840  * @val: pointer to output value.
1841  *
1842  * Return: 0 on success or negative errno.
1843  */
1844 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
1845 {
1846         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1847 }
1848 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);
1849
1850 static const void *nvmem_cell_read_variable_common(struct device *dev,
1851                                                    const char *cell_id,
1852                                                    size_t max_len, size_t *len)
1853 {
1854         struct nvmem_cell *cell;
1855         int nbits;
1856         void *buf;
1857
1858         cell = nvmem_cell_get(dev, cell_id);
1859         if (IS_ERR(cell))
1860                 return cell;
1861
1862         nbits = cell->entry->nbits;
1863         buf = nvmem_cell_read(cell, len);
1864         nvmem_cell_put(cell);
1865         if (IS_ERR(buf))
1866                 return buf;
1867
1868         /*
1869          * If nbits is set then nvmem_cell_read() can significantly exaggerate
1870          * the length of the real data. Throw away the extra junk.
1871          */
1872         if (nbits)
1873                 *len = DIV_ROUND_UP(nbits, 8);
1874
1875         if (*len > max_len) {
1876                 kfree(buf);
1877                 return ERR_PTR(-ERANGE);
1878         }
1879
1880         return buf;
1881 }
1882
1883 /**
1884  * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
1885  *
1886  * @dev: Device that requests the nvmem cell.
1887  * @cell_id: Name of nvmem cell to read.
1888  * @val: pointer to output value.
1889  *
1890  * Return: 0 on success or negative errno.
1891  */
1892 int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
1893                                     u32 *val)
1894 {
1895         size_t len;
1896         const u8 *buf;
1897         int i;
1898
1899         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1900         if (IS_ERR(buf))
1901                 return PTR_ERR(buf);
1902
1903         /* Copy w/ implicit endian conversion */
1904         *val = 0;
1905         for (i = 0; i < len; i++)
1906                 *val |= buf[i] << (8 * i);
1907
1908         kfree(buf);
1909
1910         return 0;
1911 }
1912 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);
1913
1914 /**
1915  * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
1916  *
1917  * @dev: Device that requests the nvmem cell.
1918  * @cell_id: Name of nvmem cell to read.
1919  * @val: pointer to output value.
1920  *
1921  * Return: 0 on success or negative errno.
1922  */
1923 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
1924                                     u64 *val)
1925 {
1926         size_t len;
1927         const u8 *buf;
1928         int i;
1929
1930         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1931         if (IS_ERR(buf))
1932                 return PTR_ERR(buf);
1933
1934         /* Copy w/ implicit endian conversion */
1935         *val = 0;
1936         for (i = 0; i < len; i++)
1937                 *val |= (uint64_t)buf[i] << (8 * i);
1938
1939         kfree(buf);
1940
1941         return 0;
1942 }
1943 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);
1944
1945 /**
1946  * nvmem_device_cell_read() - Read a given nvmem device and cell
1947  *
1948  * @nvmem: nvmem device to read from.
1949  * @info: nvmem cell info to be read.
1950  * @buf: buffer pointer which will be populated on successful read.
1951  *
1952  * Return: length of successful bytes read on success and negative
1953  * error code on error.
1954  */
1955 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1956                            struct nvmem_cell_info *info, void *buf)
1957 {
1958         struct nvmem_cell_entry cell;
1959         int rc;
1960         ssize_t len;
1961
1962         if (!nvmem)
1963                 return -EINVAL;
1964
1965         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1966         if (rc)
1967                 return rc;
1968
1969         rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0);
1970         if (rc)
1971                 return rc;
1972
1973         return len;
1974 }
1975 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1976
1977 /**
1978  * nvmem_device_cell_write() - Write cell to a given nvmem device
1979  *
1980  * @nvmem: nvmem device to be written to.
1981  * @info: nvmem cell info to be written.
1982  * @buf: buffer to be written to cell.
1983  *
1984  * Return: length of bytes written or negative error code on failure.
1985  */
1986 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1987                             struct nvmem_cell_info *info, void *buf)
1988 {
1989         struct nvmem_cell_entry cell;
1990         int rc;
1991
1992         if (!nvmem)
1993                 return -EINVAL;
1994
1995         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
1996         if (rc)
1997                 return rc;
1998
1999         return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
2000 }
2001 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
2002
2003 /**
2004  * nvmem_device_read() - Read from a given nvmem device
2005  *
2006  * @nvmem: nvmem device to read from.
2007  * @offset: offset in nvmem device.
2008  * @bytes: number of bytes to read.
2009  * @buf: buffer pointer which will be populated on successful read.
2010  *
2011  * Return: length of successful bytes read on success and negative
2012  * error code on error.
2013  */
2014 int nvmem_device_read(struct nvmem_device *nvmem,
2015                       unsigned int offset,
2016                       size_t bytes, void *buf)
2017 {
2018         int rc;
2019
2020         if (!nvmem)
2021                 return -EINVAL;
2022
2023         rc = nvmem_reg_read(nvmem, offset, buf, bytes);
2024
2025         if (rc)
2026                 return rc;
2027
2028         return bytes;
2029 }
2030 EXPORT_SYMBOL_GPL(nvmem_device_read);
2031
2032 /**
2033  * nvmem_device_write() - Write cell to a given nvmem device
2034  *
2035  * @nvmem: nvmem device to be written to.
2036  * @offset: offset in nvmem device.
2037  * @bytes: number of bytes to write.
2038  * @buf: buffer to be written.
2039  *
2040  * Return: length of bytes written or negative error code on failure.
2041  */
2042 int nvmem_device_write(struct nvmem_device *nvmem,
2043                        unsigned int offset,
2044                        size_t bytes, void *buf)
2045 {
2046         int rc;
2047
2048         if (!nvmem)
2049                 return -EINVAL;
2050
2051         rc = nvmem_reg_write(nvmem, offset, buf, bytes);
2052
2053         if (rc)
2054                 return rc;
2055
2056
2057         return bytes;
2058 }
2059 EXPORT_SYMBOL_GPL(nvmem_device_write);
2060
2061 /**
2062  * nvmem_add_cell_table() - register a table of cell info entries
2063  *
2064  * @table: table of cell info entries
2065  */
2066 void nvmem_add_cell_table(struct nvmem_cell_table *table)
2067 {
2068         mutex_lock(&nvmem_cell_mutex);
2069         list_add_tail(&table->node, &nvmem_cell_tables);
2070         mutex_unlock(&nvmem_cell_mutex);
2071 }
2072 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
2073
2074 /**
2075  * nvmem_del_cell_table() - remove a previously registered cell info table
2076  *
2077  * @table: table of cell info entries
2078  */
2079 void nvmem_del_cell_table(struct nvmem_cell_table *table)
2080 {
2081         mutex_lock(&nvmem_cell_mutex);
2082         list_del(&table->node);
2083         mutex_unlock(&nvmem_cell_mutex);
2084 }
2085 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
2086
2087 /**
2088  * nvmem_add_cell_lookups() - register a list of cell lookup entries
2089  *
2090  * @entries: array of cell lookup entries
2091  * @nentries: number of cell lookup entries in the array
2092  */
2093 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2094 {
2095         int i;
2096
2097         mutex_lock(&nvmem_lookup_mutex);
2098         for (i = 0; i < nentries; i++)
2099                 list_add_tail(&entries[i].node, &nvmem_lookup_list);
2100         mutex_unlock(&nvmem_lookup_mutex);
2101 }
2102 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
2103
2104 /**
2105  * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
2106  *                            entries
2107  *
2108  * @entries: array of cell lookup entries
2109  * @nentries: number of cell lookup entries in the array
2110  */
2111 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2112 {
2113         int i;
2114
2115         mutex_lock(&nvmem_lookup_mutex);
2116         for (i = 0; i < nentries; i++)
2117                 list_del(&entries[i].node);
2118         mutex_unlock(&nvmem_lookup_mutex);
2119 }
2120 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
2121
2122 /**
2123  * nvmem_dev_name() - Get the name of a given nvmem device.
2124  *
2125  * @nvmem: nvmem device.
2126  *
2127  * Return: name of the nvmem device.
2128  */
2129 const char *nvmem_dev_name(struct nvmem_device *nvmem)
2130 {
2131         return dev_name(&nvmem->dev);
2132 }
2133 EXPORT_SYMBOL_GPL(nvmem_dev_name);
2134
2135 static int __init nvmem_init(void)
2136 {
2137         return bus_register(&nvmem_bus_type);
2138 }
2139
2140 static void __exit nvmem_exit(void)
2141 {
2142         bus_unregister(&nvmem_bus_type);
2143 }
2144
2145 subsys_initcall(nvmem_init);
2146 module_exit(nvmem_exit);
2147
2148 MODULE_AUTHOR("Srinivas Kandagatla <[email protected]");
2149 MODULE_AUTHOR("Maxime Ripard <[email protected]");
2150 MODULE_DESCRIPTION("nvmem Driver Core");