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 #include "internals.h"
  23
  24 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
  25
  26 #define FLAG_COMPAT             BIT(0)
  27 struct nvmem_cell_entry {
  28         const char              *name;
  29         int                     offset;
  30         size_t                  raw_len;
  31         int                     bytes;
  32         int                     bit_offset;
  33         int                     nbits;
  34         nvmem_cell_post_process_t read_post_process;
  35         void                    *priv;
  36         struct device_node      *np;
  37         struct nvmem_device     *nvmem;
  38         struct list_head        node;
  39 };
  40
  41 struct nvmem_cell {
  42         struct nvmem_cell_entry *entry;
  43         const char              *id;
  44         int                     index;
  45 };
  46
  47 static DEFINE_MUTEX(nvmem_mutex);
  48 static DEFINE_IDA(nvmem_ida);
  49
  50 static DEFINE_MUTEX(nvmem_cell_mutex);
  51 static LIST_HEAD(nvmem_cell_tables);
  52
  53 static DEFINE_MUTEX(nvmem_lookup_mutex);
  54 static LIST_HEAD(nvmem_lookup_list);
  55
  56 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
  57
  58 static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
  59                             void *val, size_t bytes)
  60 {
  61         if (nvmem->reg_read)
  62                 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
  63
  64         return -EINVAL;
  65 }
  66
  67 static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
  68                              void *val, size_t bytes)
  69 {
  70         int ret;
  71
  72         if (nvmem->reg_write) {
  73                 gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
  74                 ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
  75                 gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
  76                 return ret;
  77         }
  78
  79         return -EINVAL;
  80 }
  81
  82 static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
  83                                       unsigned int offset, void *val,
  84                                       size_t bytes, int write)
  85 {
  86
  87         unsigned int end = offset + bytes;
  88         unsigned int kend, ksize;
  89         const struct nvmem_keepout *keepout = nvmem->keepout;
  90         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
  91         int rc;
  92
  93         /*
  94          * Skip all keepouts before the range being accessed.
  95          * Keepouts are sorted.
  96          */
  97         while ((keepout < keepoutend) && (keepout->end <= offset))
  98                 keepout++;
  99
 100         while ((offset < end) && (keepout < keepoutend)) {
 101                 /* Access the valid portion before the keepout. */
 102                 if (offset < keepout->start) {
 103                         kend = min(end, keepout->start);
 104                         ksize = kend - offset;
 105                         if (write)
 106                                 rc = __nvmem_reg_write(nvmem, offset, val, ksize);
 107                         else
 108                                 rc = __nvmem_reg_read(nvmem, offset, val, ksize);
 109
 110                         if (rc)
 111                                 return rc;
 112
 113                         offset += ksize;
 114                         val += ksize;
 115                 }
 116
 117                 /*
 118                  * Now we're aligned to the start of this keepout zone. Go
 119                  * through it.
 120                  */
 121                 kend = min(end, keepout->end);
 122                 ksize = kend - offset;
 123                 if (!write)
 124                         memset(val, keepout->value, ksize);
 125
 126                 val += ksize;
 127                 offset += ksize;
 128                 keepout++;
 129         }
 130
 131         /*
 132          * If we ran out of keepouts but there's still stuff to do, send it
 133          * down directly
 134          */
 135         if (offset < end) {
 136                 ksize = end - offset;
 137                 if (write)
 138                         return __nvmem_reg_write(nvmem, offset, val, ksize);
 139                 else
 140                         return __nvmem_reg_read(nvmem, offset, val, ksize);
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 147                           void *val, size_t bytes)
 148 {
 149         if (!nvmem->nkeepout)
 150                 return __nvmem_reg_read(nvmem, offset, val, bytes);
 151
 152         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
 153 }
 154
 155 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
 156                            void *val, size_t bytes)
 157 {
 158         if (!nvmem->nkeepout)
 159                 return __nvmem_reg_write(nvmem, offset, val, bytes);
 160
 161         return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true);
 162 }
 163
 164 #ifdef CONFIG_NVMEM_SYSFS
 165 static const char * const nvmem_type_str[] = {
 166         [NVMEM_TYPE_UNKNOWN] = "Unknown",
 167         [NVMEM_TYPE_EEPROM] = "EEPROM",
 168         [NVMEM_TYPE_OTP] = "OTP",
 169         [NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
 170         [NVMEM_TYPE_FRAM] = "FRAM",
 171 };
 172
 173 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 174 static struct lock_class_key eeprom_lock_key;
 175 #endif
 176
 177 static ssize_t type_show(struct device *dev,
 178                          struct device_attribute *attr, char *buf)
 179 {
 180         struct nvmem_device *nvmem = to_nvmem_device(dev);
 181
 182         return sysfs_emit(buf, "%s\n", nvmem_type_str[nvmem->type]);
 183 }
 184
 185 static DEVICE_ATTR_RO(type);
 186
 187 static ssize_t force_ro_show(struct device *dev, struct device_attribute *attr,
 188                              char *buf)
 189 {
 190         struct nvmem_device *nvmem = to_nvmem_device(dev);
 191
 192         return sysfs_emit(buf, "%d\n", nvmem->read_only);
 193 }
 194
 195 static ssize_t force_ro_store(struct device *dev, struct device_attribute *attr,
 196                               const char *buf, size_t count)
 197 {
 198         struct nvmem_device *nvmem = to_nvmem_device(dev);
 199         int ret = kstrtobool(buf, &nvmem->read_only);
 200
 201         if (ret < 0)
 202                 return ret;
 203
 204         return count;
 205 }
 206
 207 static DEVICE_ATTR_RW(force_ro);
 208
 209 static struct attribute *nvmem_attrs[] = {
 210         &dev_attr_force_ro.attr,
 211         &dev_attr_type.attr,
 212         NULL,
 213 };
 214
 215 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
 216                                    struct bin_attribute *attr, char *buf,
 217                                    loff_t pos, size_t count)
 218 {
 219         struct device *dev;
 220         struct nvmem_device *nvmem;
 221         int rc;
 222
 223         if (attr->private)
 224                 dev = attr->private;
 225         else
 226                 dev = kobj_to_dev(kobj);
 227         nvmem = to_nvmem_device(dev);
 228
 229         if (!IS_ALIGNED(pos, nvmem->stride))
 230                 return -EINVAL;
 231
 232         if (count < nvmem->word_size)
 233                 return -EINVAL;
 234
 235         count = round_down(count, nvmem->word_size);
 236
 237         if (!nvmem->reg_read)
 238                 return -EPERM;
 239
 240         rc = nvmem_reg_read(nvmem, pos, buf, count);
 241
 242         if (rc)
 243                 return rc;
 244
 245         return count;
 246 }
 247
 248 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
 249                                     struct bin_attribute *attr, char *buf,
 250                                     loff_t pos, size_t count)
 251 {
 252         struct device *dev;
 253         struct nvmem_device *nvmem;
 254         int rc;
 255
 256         if (attr->private)
 257                 dev = attr->private;
 258         else
 259                 dev = kobj_to_dev(kobj);
 260         nvmem = to_nvmem_device(dev);
 261
 262         if (!IS_ALIGNED(pos, nvmem->stride))
 263                 return -EINVAL;
 264
 265         if (count < nvmem->word_size)
 266                 return -EINVAL;
 267
 268         count = round_down(count, nvmem->word_size);
 269
 270         if (!nvmem->reg_write || nvmem->read_only)
 271                 return -EPERM;
 272
 273         rc = nvmem_reg_write(nvmem, pos, buf, count);
 274
 275         if (rc)
 276                 return rc;
 277
 278         return count;
 279 }
 280
 281 static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
 282 {
 283         umode_t mode = 0400;
 284
 285         if (!nvmem->root_only)
 286                 mode |= 0044;
 287
 288         if (!nvmem->read_only)
 289                 mode |= 0200;
 290
 291         if (!nvmem->reg_write)
 292                 mode &= ~0200;
 293
 294         if (!nvmem->reg_read)
 295                 mode &= ~0444;
 296
 297         return mode;
 298 }
 299
 300 static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
 301                                          const struct bin_attribute *attr,
 302                                          int i)
 303 {
 304         struct device *dev = kobj_to_dev(kobj);
 305         struct nvmem_device *nvmem = to_nvmem_device(dev);
 306
 307         return nvmem_bin_attr_get_umode(nvmem);
 308 }
 309
 310 static size_t nvmem_bin_attr_size(struct kobject *kobj,
 311                                   const struct bin_attribute *attr,
 312                                   int i)
 313 {
 314         struct device *dev = kobj_to_dev(kobj);
 315         struct nvmem_device *nvmem = to_nvmem_device(dev);
 316
 317         return nvmem->size;
 318 }
 319
 320 static umode_t nvmem_attr_is_visible(struct kobject *kobj,
 321                                      struct attribute *attr, int i)
 322 {
 323         struct device *dev = kobj_to_dev(kobj);
 324         struct nvmem_device *nvmem = to_nvmem_device(dev);
 325
 326         /*
 327          * If the device has no .reg_write operation, do not allow
 328          * configuration as read-write.
 329          * If the device is set as read-only by configuration, it
 330          * can be forced into read-write mode using the 'force_ro'
 331          * attribute.
 332          */
 333         if (attr == &dev_attr_force_ro.attr && !nvmem->reg_write)
 334                 return 0;       /* Attribute not visible */
 335
 336         return attr->mode;
 337 }
 338
 339 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
 340                                             const char *id, int index);
 341
 342 static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj,
 343                                     struct bin_attribute *attr, char *buf,
 344                                     loff_t pos, size_t count)
 345 {
 346         struct nvmem_cell_entry *entry;
 347         struct nvmem_cell *cell = NULL;
 348         size_t cell_sz, read_len;
 349         void *content;
 350
 351         entry = attr->private;
 352         cell = nvmem_create_cell(entry, entry->name, 0);
 353         if (IS_ERR(cell))
 354                 return PTR_ERR(cell);
 355
 356         if (!cell)
 357                 return -EINVAL;
 358
 359         content = nvmem_cell_read(cell, &cell_sz);
 360         if (IS_ERR(content)) {
 361                 read_len = PTR_ERR(content);
 362                 goto destroy_cell;
 363         }
 364
 365         read_len = min_t(unsigned int, cell_sz - pos, count);
 366         memcpy(buf, content + pos, read_len);
 367         kfree(content);
 368
 369 destroy_cell:
 370         kfree_const(cell->id);
 371         kfree(cell);
 372
 373         return read_len;
 374 }
 375
 376 /* default read/write permissions */
 377 static struct bin_attribute bin_attr_rw_nvmem = {
 378         .attr   = {
 379                 .name   = "nvmem",
 380                 .mode   = 0644,
 381         },
 382         .read   = bin_attr_nvmem_read,
 383         .write  = bin_attr_nvmem_write,
 384 };
 385
 386 static struct bin_attribute *nvmem_bin_attributes[] = {
 387         &bin_attr_rw_nvmem,
 388         NULL,
 389 };
 390
 391 static const struct attribute_group nvmem_bin_group = {
 392         .bin_attrs      = nvmem_bin_attributes,
 393         .attrs          = nvmem_attrs,
 394         .is_bin_visible = nvmem_bin_attr_is_visible,
 395         .bin_size       = nvmem_bin_attr_size,
 396         .is_visible     = nvmem_attr_is_visible,
 397 };
 398
 399 static const struct attribute_group *nvmem_dev_groups[] = {
 400         &nvmem_bin_group,
 401         NULL,
 402 };
 403
 404 static struct bin_attribute bin_attr_nvmem_eeprom_compat = {
 405         .attr   = {
 406                 .name   = "eeprom",
 407         },
 408         .read   = bin_attr_nvmem_read,
 409         .write  = bin_attr_nvmem_write,
 410 };
 411
 412 /*
 413  * nvmem_setup_compat() - Create an additional binary entry in
 414  * drivers sys directory, to be backwards compatible with the older
 415  * drivers/misc/eeprom drivers.
 416  */
 417 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 418                                     const struct nvmem_config *config)
 419 {
 420         int rval;
 421
 422         if (!config->compat)
 423                 return 0;
 424
 425         if (!config->base_dev)
 426                 return -EINVAL;
 427
 428         nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
 429         if (config->type == NVMEM_TYPE_FRAM)
 430                 nvmem->eeprom.attr.name = "fram";
 431         nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
 432         nvmem->eeprom.size = nvmem->size;
 433 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 434         nvmem->eeprom.attr.key = &eeprom_lock_key;
 435 #endif
 436         nvmem->eeprom.private = &nvmem->dev;
 437         nvmem->base_dev = config->base_dev;
 438
 439         rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
 440         if (rval) {
 441                 dev_err(&nvmem->dev,
 442                         "Failed to create eeprom binary file %d\n", rval);
 443                 return rval;
 444         }
 445
 446         nvmem->flags |= FLAG_COMPAT;
 447
 448         return 0;
 449 }
 450
 451 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 452                               const struct nvmem_config *config)
 453 {
 454         if (config->compat)
 455                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 456 }
 457
 458 static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)
 459 {
 460         struct attribute_group group = {
 461                 .name   = "cells",
 462         };
 463         struct nvmem_cell_entry *entry;
 464         struct bin_attribute *attrs;
 465         unsigned int ncells = 0, i = 0;
 466         int ret = 0;
 467
 468         mutex_lock(&nvmem_mutex);
 469
 470         if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated)
 471                 goto unlock_mutex;
 472
 473         /* Allocate an array of attributes with a sentinel */
 474         ncells = list_count_nodes(&nvmem->cells);
 475         group.bin_attrs = devm_kcalloc(&nvmem->dev, ncells + 1,
 476                                        sizeof(struct bin_attribute *), GFP_KERNEL);
 477         if (!group.bin_attrs) {
 478                 ret = -ENOMEM;
 479                 goto unlock_mutex;
 480         }
 481
 482         attrs = devm_kcalloc(&nvmem->dev, ncells, sizeof(struct bin_attribute), GFP_KERNEL);
 483         if (!attrs) {
 484                 ret = -ENOMEM;
 485                 goto unlock_mutex;
 486         }
 487
 488         /* Initialize each attribute to take the name and size of the cell */
 489         list_for_each_entry(entry, &nvmem->cells, node) {
 490                 sysfs_bin_attr_init(&attrs[i]);
 491                 attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL,
 492                                                     "%s@%x,%x", entry->name,
 493                                                     entry->offset,
 494                                                     entry->bit_offset);
 495                 attrs[i].attr.mode = 0444 & nvmem_bin_attr_get_umode(nvmem);
 496                 attrs[i].size = entry->bytes;
 497                 attrs[i].read = &nvmem_cell_attr_read;
 498                 attrs[i].private = entry;
 499                 if (!attrs[i].attr.name) {
 500                         ret = -ENOMEM;
 501                         goto unlock_mutex;
 502                 }
 503
 504                 group.bin_attrs[i] = &attrs[i];
 505                 i++;
 506         }
 507
 508         ret = device_add_group(&nvmem->dev, &group);
 509         if (ret)
 510                 goto unlock_mutex;
 511
 512         nvmem->sysfs_cells_populated = true;
 513
 514 unlock_mutex:
 515         mutex_unlock(&nvmem_mutex);
 516
 517         return ret;
 518 }
 519
 520 #else /* CONFIG_NVMEM_SYSFS */
 521
 522 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
 523                                     const struct nvmem_config *config)
 524 {
 525         return -ENOSYS;
 526 }
 527 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 528                                       const struct nvmem_config *config)
 529 {
 530 }
 531
 532 #endif /* CONFIG_NVMEM_SYSFS */
 533
 534 static void nvmem_release(struct device *dev)
 535 {
 536         struct nvmem_device *nvmem = to_nvmem_device(dev);
 537
 538         ida_free(&nvmem_ida, nvmem->id);
 539         gpiod_put(nvmem->wp_gpio);
 540         kfree(nvmem);
 541 }
 542
 543 static const struct device_type nvmem_provider_type = {
 544         .release        = nvmem_release,
 545 };
 546
 547 static struct bus_type nvmem_bus_type = {
 548         .name           = "nvmem",
 549 };
 550
 551 static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell)
 552 {
 553         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
 554         mutex_lock(&nvmem_mutex);
 555         list_del(&cell->node);
 556         mutex_unlock(&nvmem_mutex);
 557         of_node_put(cell->np);
 558         kfree_const(cell->name);
 559         kfree(cell);
 560 }
 561
 562 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
 563 {
 564         struct nvmem_cell_entry *cell, *p;
 565
 566         list_for_each_entry_safe(cell, p, &nvmem->cells, node)
 567                 nvmem_cell_entry_drop(cell);
 568 }
 569
 570 static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell)
 571 {
 572         mutex_lock(&nvmem_mutex);
 573         list_add_tail(&cell->node, &cell->nvmem->cells);
 574         mutex_unlock(&nvmem_mutex);
 575         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
 576 }
 577
 578 static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 579                                                      const struct nvmem_cell_info *info,
 580                                                      struct nvmem_cell_entry *cell)
 581 {
 582         cell->nvmem = nvmem;
 583         cell->offset = info->offset;
 584         cell->raw_len = info->raw_len ?: info->bytes;
 585         cell->bytes = info->bytes;
 586         cell->name = info->name;
 587         cell->read_post_process = info->read_post_process;
 588         cell->priv = info->priv;
 589
 590         cell->bit_offset = info->bit_offset;
 591         cell->nbits = info->nbits;
 592         cell->np = info->np;
 593
 594         if (cell->nbits)
 595                 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
 596                                            BITS_PER_BYTE);
 597
 598         if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 599                 dev_err(&nvmem->dev,
 600                         "cell %s unaligned to nvmem stride %d\n",
 601                         cell->name ?: "<unknown>", nvmem->stride);
 602                 return -EINVAL;
 603         }
 604
 605         return 0;
 606 }
 607
 608 static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 609                                                const struct nvmem_cell_info *info,
 610                                                struct nvmem_cell_entry *cell)
 611 {
 612         int err;
 613
 614         err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell);
 615         if (err)
 616                 return err;
 617
 618         cell->name = kstrdup_const(info->name, GFP_KERNEL);
 619         if (!cell->name)
 620                 return -ENOMEM;
 621
 622         return 0;
 623 }
 624
 625 /**
 626  * nvmem_add_one_cell() - Add one cell information to an nvmem device
 627  *
 628  * @nvmem: nvmem device to add cells to.
 629  * @info: nvmem cell info to add to the device
 630  *
 631  * Return: 0 or negative error code on failure.
 632  */
 633 int nvmem_add_one_cell(struct nvmem_device *nvmem,
 634                        const struct nvmem_cell_info *info)
 635 {
 636         struct nvmem_cell_entry *cell;
 637         int rval;
 638
 639         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 640         if (!cell)
 641                 return -ENOMEM;
 642
 643         rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 644         if (rval) {
 645                 kfree(cell);
 646                 return rval;
 647         }
 648
 649         nvmem_cell_entry_add(cell);
 650
 651         return 0;
 652 }
 653 EXPORT_SYMBOL_GPL(nvmem_add_one_cell);
 654
 655 /**
 656  * nvmem_add_cells() - Add cell information to an nvmem device
 657  *
 658  * @nvmem: nvmem device to add cells to.
 659  * @info: nvmem cell info to add to the device
 660  * @ncells: number of cells in info
 661  *
 662  * Return: 0 or negative error code on failure.
 663  */
 664 static int nvmem_add_cells(struct nvmem_device *nvmem,
 665                     const struct nvmem_cell_info *info,
 666                     int ncells)
 667 {
 668         int i, rval;
 669
 670         for (i = 0; i < ncells; i++) {
 671                 rval = nvmem_add_one_cell(nvmem, &info[i]);
 672                 if (rval)
 673                         return rval;
 674         }
 675
 676         return 0;
 677 }
 678
 679 /**
 680  * nvmem_register_notifier() - Register a notifier block for nvmem events.
 681  *
 682  * @nb: notifier block to be called on nvmem events.
 683  *
 684  * Return: 0 on success, negative error number on failure.
 685  */
 686 int nvmem_register_notifier(struct notifier_block *nb)
 687 {
 688         return blocking_notifier_chain_register(&nvmem_notifier, nb);
 689 }
 690 EXPORT_SYMBOL_GPL(nvmem_register_notifier);
 691
 692 /**
 693  * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
 694  *
 695  * @nb: notifier block to be unregistered.
 696  *
 697  * Return: 0 on success, negative error number on failure.
 698  */
 699 int nvmem_unregister_notifier(struct notifier_block *nb)
 700 {
 701         return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
 702 }
 703 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
 704
 705 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
 706 {
 707         const struct nvmem_cell_info *info;
 708         struct nvmem_cell_table *table;
 709         struct nvmem_cell_entry *cell;
 710         int rval = 0, i;
 711
 712         mutex_lock(&nvmem_cell_mutex);
 713         list_for_each_entry(table, &nvmem_cell_tables, node) {
 714                 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
 715                         for (i = 0; i < table->ncells; i++) {
 716                                 info = &table->cells[i];
 717
 718                                 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
 719                                 if (!cell) {
 720                                         rval = -ENOMEM;
 721                                         goto out;
 722                                 }
 723
 724                                 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
 725                                 if (rval) {
 726                                         kfree(cell);
 727                                         goto out;
 728                                 }
 729
 730                                 nvmem_cell_entry_add(cell);
 731                         }
 732                 }
 733         }
 734
 735 out:
 736         mutex_unlock(&nvmem_cell_mutex);
 737         return rval;
 738 }
 739
 740 static struct nvmem_cell_entry *
 741 nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id)
 742 {
 743         struct nvmem_cell_entry *iter, *cell = NULL;
 744
 745         mutex_lock(&nvmem_mutex);
 746         list_for_each_entry(iter, &nvmem->cells, node) {
 747                 if (strcmp(cell_id, iter->name) == 0) {
 748                         cell = iter;
 749                         break;
 750                 }
 751         }
 752         mutex_unlock(&nvmem_mutex);
 753
 754         return cell;
 755 }
 756
 757 static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 758 {
 759         unsigned int cur = 0;
 760         const struct nvmem_keepout *keepout = nvmem->keepout;
 761         const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
 762
 763         while (keepout < keepoutend) {
 764                 /* Ensure keepouts are sorted and don't overlap. */
 765                 if (keepout->start < cur) {
 766                         dev_err(&nvmem->dev,
 767                                 "Keepout regions aren't sorted or overlap.\n");
 768
 769                         return -ERANGE;
 770                 }
 771
 772                 if (keepout->end < keepout->start) {
 773                         dev_err(&nvmem->dev,
 774                                 "Invalid keepout region.\n");
 775
 776                         return -EINVAL;
 777                 }
 778
 779                 /*
 780                  * Validate keepouts (and holes between) don't violate
 781                  * word_size constraints.
 782                  */
 783                 if ((keepout->end - keepout->start < nvmem->word_size) ||
 784                     ((keepout->start != cur) &&
 785                      (keepout->start - cur < nvmem->word_size))) {
 786
 787                         dev_err(&nvmem->dev,
 788                                 "Keepout regions violate word_size constraints.\n");
 789
 790                         return -ERANGE;
 791                 }
 792
 793                 /* Validate keepouts don't violate stride (alignment). */
 794                 if (!IS_ALIGNED(keepout->start, nvmem->stride) ||
 795                     !IS_ALIGNED(keepout->end, nvmem->stride)) {
 796
 797                         dev_err(&nvmem->dev,
 798                                 "Keepout regions violate stride.\n");
 799
 800                         return -EINVAL;
 801                 }
 802
 803                 cur = keepout->end;
 804                 keepout++;
 805         }
 806
 807         return 0;
 808 }
 809
 810 static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np)
 811 {
 812         struct device *dev = &nvmem->dev;
 813         struct device_node *child;
 814         const __be32 *addr;
 815         int len, ret;
 816
 817         for_each_child_of_node(np, child) {
 818                 struct nvmem_cell_info info = {0};
 819
 820                 addr = of_get_property(child, "reg", &len);
 821                 if (!addr)
 822                         continue;
 823                 if (len < 2 * sizeof(u32)) {
 824                         dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
 825                         of_node_put(child);
 826                         return -EINVAL;
 827                 }
 828
 829                 info.offset = be32_to_cpup(addr++);
 830                 info.bytes = be32_to_cpup(addr);
 831                 info.name = kasprintf(GFP_KERNEL, "%pOFn", child);
 832
 833                 addr = of_get_property(child, "bits", &len);
 834                 if (addr && len == (2 * sizeof(u32))) {
 835                         info.bit_offset = be32_to_cpup(addr++);
 836                         info.nbits = be32_to_cpup(addr);
 837                         if (info.bit_offset >= BITS_PER_BYTE || info.nbits < 1) {
 838                                 dev_err(dev, "nvmem: invalid bits on %pOF\n", child);
 839                                 of_node_put(child);
 840                                 return -EINVAL;
 841                         }
 842                 }
 843
 844                 info.np = of_node_get(child);
 845
 846                 if (nvmem->fixup_dt_cell_info)
 847                         nvmem->fixup_dt_cell_info(nvmem, &info);
 848
 849                 ret = nvmem_add_one_cell(nvmem, &info);
 850                 kfree(info.name);
 851                 if (ret) {
 852                         of_node_put(child);
 853                         return ret;
 854                 }
 855         }
 856
 857         return 0;
 858 }
 859
 860 static int nvmem_add_cells_from_legacy_of(struct nvmem_device *nvmem)
 861 {
 862         return nvmem_add_cells_from_dt(nvmem, nvmem->dev.of_node);
 863 }
 864
 865 static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem)
 866 {
 867         struct device_node *layout_np;
 868         int err = 0;
 869
 870         layout_np = of_nvmem_layout_get_container(nvmem);
 871         if (!layout_np)
 872                 return 0;
 873
 874         if (of_device_is_compatible(layout_np, "fixed-layout"))
 875                 err = nvmem_add_cells_from_dt(nvmem, layout_np);
 876
 877         of_node_put(layout_np);
 878
 879         return err;
 880 }
 881
 882 int nvmem_layout_register(struct nvmem_layout *layout)
 883 {
 884         int ret;
 885
 886         if (!layout->add_cells)
 887                 return -EINVAL;
 888
 889         /* Populate the cells */
 890         ret = layout->add_cells(layout);
 891         if (ret)
 892                 return ret;
 893
 894 #ifdef CONFIG_NVMEM_SYSFS
 895         ret = nvmem_populate_sysfs_cells(layout->nvmem);
 896         if (ret) {
 897                 nvmem_device_remove_all_cells(layout->nvmem);
 898                 return ret;
 899         }
 900 #endif
 901
 902         return 0;
 903 }
 904 EXPORT_SYMBOL_GPL(nvmem_layout_register);
 905
 906 void nvmem_layout_unregister(struct nvmem_layout *layout)
 907 {
 908         /* Keep the API even with an empty stub in case we need it later */
 909 }
 910 EXPORT_SYMBOL_GPL(nvmem_layout_unregister);
 911
 912 /**
 913  * nvmem_register() - Register a nvmem device for given nvmem_config.
 914  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 915  *
 916  * @config: nvmem device configuration with which nvmem device is created.
 917  *
 918  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 919  * on success.
 920  */
 921
 922 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 923 {
 924         struct nvmem_device *nvmem;
 925         int rval;
 926
 927         if (!config->dev)
 928                 return ERR_PTR(-EINVAL);
 929
 930         if (!config->reg_read && !config->reg_write)
 931                 return ERR_PTR(-EINVAL);
 932
 933         nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
 934         if (!nvmem)
 935                 return ERR_PTR(-ENOMEM);
 936
 937         rval = ida_alloc(&nvmem_ida, GFP_KERNEL);
 938         if (rval < 0) {
 939                 kfree(nvmem);
 940                 return ERR_PTR(rval);
 941         }
 942
 943         nvmem->id = rval;
 944
 945         nvmem->dev.type = &nvmem_provider_type;
 946         nvmem->dev.bus = &nvmem_bus_type;
 947         nvmem->dev.parent = config->dev;
 948
 949         device_initialize(&nvmem->dev);
 950
 951         if (!config->ignore_wp)
 952                 nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
 953                                                     GPIOD_OUT_HIGH);
 954         if (IS_ERR(nvmem->wp_gpio)) {
 955                 rval = PTR_ERR(nvmem->wp_gpio);
 956                 nvmem->wp_gpio = NULL;
 957                 goto err_put_device;
 958         }
 959
 960         kref_init(&nvmem->refcnt);
 961         INIT_LIST_HEAD(&nvmem->cells);
 962         nvmem->fixup_dt_cell_info = config->fixup_dt_cell_info;
 963
 964         nvmem->owner = config->owner;
 965         if (!nvmem->owner && config->dev->driver)
 966                 nvmem->owner = config->dev->driver->owner;
 967         nvmem->stride = config->stride ?: 1;
 968         nvmem->word_size = config->word_size ?: 1;
 969         nvmem->size = config->size;
 970         nvmem->root_only = config->root_only;
 971         nvmem->priv = config->priv;
 972         nvmem->type = config->type;
 973         nvmem->reg_read = config->reg_read;
 974         nvmem->reg_write = config->reg_write;
 975         nvmem->keepout = config->keepout;
 976         nvmem->nkeepout = config->nkeepout;
 977         if (config->of_node)
 978                 nvmem->dev.of_node = config->of_node;
 979         else
 980                 nvmem->dev.of_node = config->dev->of_node;
 981
 982         switch (config->id) {
 983         case NVMEM_DEVID_NONE:
 984                 rval = dev_set_name(&nvmem->dev, "%s", config->name);
 985                 break;
 986         case NVMEM_DEVID_AUTO:
 987                 rval = dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
 988                 break;
 989         default:
 990                 rval = dev_set_name(&nvmem->dev, "%s%d",
 991                              config->name ? : "nvmem",
 992                              config->name ? config->id : nvmem->id);
 993                 break;
 994         }
 995
 996         if (rval)
 997                 goto err_put_device;
 998
 999         nvmem->read_only = device_property_present(config->dev, "read-only") ||
1000                            config->read_only || !nvmem->reg_write;
1001
1002 #ifdef CONFIG_NVMEM_SYSFS
1003         nvmem->dev.groups = nvmem_dev_groups;
1004 #endif
1005
1006         if (nvmem->nkeepout) {
1007                 rval = nvmem_validate_keepouts(nvmem);
1008                 if (rval)
1009                         goto err_put_device;
1010         }
1011
1012         if (config->compat) {
1013                 rval = nvmem_sysfs_setup_compat(nvmem, config);
1014                 if (rval)
1015                         goto err_put_device;
1016         }
1017
1018         if (config->cells) {
1019                 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
1020                 if (rval)
1021                         goto err_remove_cells;
1022         }
1023
1024         rval = nvmem_add_cells_from_table(nvmem);
1025         if (rval)
1026                 goto err_remove_cells;
1027
1028         if (config->add_legacy_fixed_of_cells) {
1029                 rval = nvmem_add_cells_from_legacy_of(nvmem);
1030                 if (rval)
1031                         goto err_remove_cells;
1032         }
1033
1034         rval = nvmem_add_cells_from_fixed_layout(nvmem);
1035         if (rval)
1036                 goto err_remove_cells;
1037
1038         dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
1039
1040         rval = device_add(&nvmem->dev);
1041         if (rval)
1042                 goto err_remove_cells;
1043
1044         rval = nvmem_populate_layout(nvmem);
1045         if (rval)
1046                 goto err_remove_dev;
1047
1048 #ifdef CONFIG_NVMEM_SYSFS
1049         rval = nvmem_populate_sysfs_cells(nvmem);
1050         if (rval)
1051                 goto err_destroy_layout;
1052 #endif
1053
1054         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
1055
1056         return nvmem;
1057
1058 #ifdef CONFIG_NVMEM_SYSFS
1059 err_destroy_layout:
1060         nvmem_destroy_layout(nvmem);
1061 #endif
1062 err_remove_dev:
1063         device_del(&nvmem->dev);
1064 err_remove_cells:
1065         nvmem_device_remove_all_cells(nvmem);
1066         if (config->compat)
1067                 nvmem_sysfs_remove_compat(nvmem, config);
1068 err_put_device:
1069         put_device(&nvmem->dev);
1070
1071         return ERR_PTR(rval);
1072 }
1073 EXPORT_SYMBOL_GPL(nvmem_register);
1074
1075 static void nvmem_device_release(struct kref *kref)
1076 {
1077         struct nvmem_device *nvmem;
1078
1079         nvmem = container_of(kref, struct nvmem_device, refcnt);
1080
1081         blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
1082
1083         if (nvmem->flags & FLAG_COMPAT)
1084                 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
1085
1086         nvmem_device_remove_all_cells(nvmem);
1087         nvmem_destroy_layout(nvmem);
1088         device_unregister(&nvmem->dev);
1089 }
1090
1091 /**
1092  * nvmem_unregister() - Unregister previously registered nvmem device
1093  *
1094  * @nvmem: Pointer to previously registered nvmem device.
1095  */
1096 void nvmem_unregister(struct nvmem_device *nvmem)
1097 {
1098         if (nvmem)
1099                 kref_put(&nvmem->refcnt, nvmem_device_release);
1100 }
1101 EXPORT_SYMBOL_GPL(nvmem_unregister);
1102
1103 static void devm_nvmem_unregister(void *nvmem)
1104 {
1105         nvmem_unregister(nvmem);
1106 }
1107
1108 /**
1109  * devm_nvmem_register() - Register a managed nvmem device for given
1110  * nvmem_config.
1111  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
1112  *
1113  * @dev: Device that uses the nvmem device.
1114  * @config: nvmem device configuration with which nvmem device is created.
1115  *
1116  * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
1117  * on success.
1118  */
1119 struct nvmem_device *devm_nvmem_register(struct device *dev,
1120                                          const struct nvmem_config *config)
1121 {
1122         struct nvmem_device *nvmem;
1123         int ret;
1124
1125         nvmem = nvmem_register(config);
1126         if (IS_ERR(nvmem))
1127                 return nvmem;
1128
1129         ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem);
1130         if (ret)
1131                 return ERR_PTR(ret);
1132
1133         return nvmem;
1134 }
1135 EXPORT_SYMBOL_GPL(devm_nvmem_register);
1136
1137 static struct nvmem_device *__nvmem_device_get(void *data,
1138                         int (*match)(struct device *dev, const void *data))
1139 {
1140         struct nvmem_device *nvmem = NULL;
1141         struct device *dev;
1142
1143         mutex_lock(&nvmem_mutex);
1144         dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
1145         if (dev)
1146                 nvmem = to_nvmem_device(dev);
1147         mutex_unlock(&nvmem_mutex);
1148         if (!nvmem)
1149                 return ERR_PTR(-EPROBE_DEFER);
1150
1151         if (!try_module_get(nvmem->owner)) {
1152                 dev_err(&nvmem->dev,
1153                         "could not increase module refcount for cell %s\n",
1154                         nvmem_dev_name(nvmem));
1155
1156                 put_device(&nvmem->dev);
1157                 return ERR_PTR(-EINVAL);
1158         }
1159
1160         kref_get(&nvmem->refcnt);
1161
1162         return nvmem;
1163 }
1164
1165 static void __nvmem_device_put(struct nvmem_device *nvmem)
1166 {
1167         put_device(&nvmem->dev);
1168         module_put(nvmem->owner);
1169         kref_put(&nvmem->refcnt, nvmem_device_release);
1170 }
1171
1172 #if IS_ENABLED(CONFIG_OF)
1173 /**
1174  * of_nvmem_device_get() - Get nvmem device from a given id
1175  *
1176  * @np: Device tree node that uses the nvmem device.
1177  * @id: nvmem name from nvmem-names property.
1178  *
1179  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1180  * on success.
1181  */
1182 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
1183 {
1184
1185         struct device_node *nvmem_np;
1186         struct nvmem_device *nvmem;
1187         int index = 0;
1188
1189         if (id)
1190                 index = of_property_match_string(np, "nvmem-names", id);
1191
1192         nvmem_np = of_parse_phandle(np, "nvmem", index);
1193         if (!nvmem_np)
1194                 return ERR_PTR(-ENOENT);
1195
1196         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1197         of_node_put(nvmem_np);
1198         return nvmem;
1199 }
1200 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
1201 #endif
1202
1203 /**
1204  * nvmem_device_get() - Get nvmem device from a given id
1205  *
1206  * @dev: Device that uses the nvmem device.
1207  * @dev_name: name of the requested nvmem device.
1208  *
1209  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1210  * on success.
1211  */
1212 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
1213 {
1214         if (dev->of_node) { /* try dt first */
1215                 struct nvmem_device *nvmem;
1216
1217                 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
1218
1219                 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
1220                         return nvmem;
1221
1222         }
1223
1224         return __nvmem_device_get((void *)dev_name, device_match_name);
1225 }
1226 EXPORT_SYMBOL_GPL(nvmem_device_get);
1227
1228 /**
1229  * nvmem_device_find() - Find nvmem device with matching function
1230  *
1231  * @data: Data to pass to match function
1232  * @match: Callback function to check device
1233  *
1234  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1235  * on success.
1236  */
1237 struct nvmem_device *nvmem_device_find(void *data,
1238                         int (*match)(struct device *dev, const void *data))
1239 {
1240         return __nvmem_device_get(data, match);
1241 }
1242 EXPORT_SYMBOL_GPL(nvmem_device_find);
1243
1244 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
1245 {
1246         struct nvmem_device **nvmem = res;
1247
1248         if (WARN_ON(!nvmem || !*nvmem))
1249                 return 0;
1250
1251         return *nvmem == data;
1252 }
1253
1254 static void devm_nvmem_device_release(struct device *dev, void *res)
1255 {
1256         nvmem_device_put(*(struct nvmem_device **)res);
1257 }
1258
1259 /**
1260  * devm_nvmem_device_put() - put already got nvmem device
1261  *
1262  * @dev: Device that uses the nvmem device.
1263  * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
1264  * that needs to be released.
1265  */
1266 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
1267 {
1268         int ret;
1269
1270         ret = devres_release(dev, devm_nvmem_device_release,
1271                              devm_nvmem_device_match, nvmem);
1272
1273         WARN_ON(ret);
1274 }
1275 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
1276
1277 /**
1278  * nvmem_device_put() - put already got nvmem device
1279  *
1280  * @nvmem: pointer to nvmem device that needs to be released.
1281  */
1282 void nvmem_device_put(struct nvmem_device *nvmem)
1283 {
1284         __nvmem_device_put(nvmem);
1285 }
1286 EXPORT_SYMBOL_GPL(nvmem_device_put);
1287
1288 /**
1289  * devm_nvmem_device_get() - Get nvmem device of device form a given id
1290  *
1291  * @dev: Device that requests the nvmem device.
1292  * @id: name id for the requested nvmem device.
1293  *
1294  * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1295  * on success.  The nvmem_device will be freed by the automatically once the
1296  * device is freed.
1297  */
1298 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
1299 {
1300         struct nvmem_device **ptr, *nvmem;
1301
1302         ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
1303         if (!ptr)
1304                 return ERR_PTR(-ENOMEM);
1305
1306         nvmem = nvmem_device_get(dev, id);
1307         if (!IS_ERR(nvmem)) {
1308                 *ptr = nvmem;
1309                 devres_add(dev, ptr);
1310         } else {
1311                 devres_free(ptr);
1312         }
1313
1314         return nvmem;
1315 }
1316 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
1317
1318 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
1319                                             const char *id, int index)
1320 {
1321         struct nvmem_cell *cell;
1322         const char *name = NULL;
1323
1324         cell = kzalloc(sizeof(*cell), GFP_KERNEL);
1325         if (!cell)
1326                 return ERR_PTR(-ENOMEM);
1327
1328         if (id) {
1329                 name = kstrdup_const(id, GFP_KERNEL);
1330                 if (!name) {
1331                         kfree(cell);
1332                         return ERR_PTR(-ENOMEM);
1333                 }
1334         }
1335
1336         cell->id = name;
1337         cell->entry = entry;
1338         cell->index = index;
1339
1340         return cell;
1341 }
1342
1343 static struct nvmem_cell *
1344 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
1345 {
1346         struct nvmem_cell_entry *cell_entry;
1347         struct nvmem_cell *cell = ERR_PTR(-ENOENT);
1348         struct nvmem_cell_lookup *lookup;
1349         struct nvmem_device *nvmem;
1350         const char *dev_id;
1351
1352         if (!dev)
1353                 return ERR_PTR(-EINVAL);
1354
1355         dev_id = dev_name(dev);
1356
1357         mutex_lock(&nvmem_lookup_mutex);
1358
1359         list_for_each_entry(lookup, &nvmem_lookup_list, node) {
1360                 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
1361                     (strcmp(lookup->con_id, con_id) == 0)) {
1362                         /* This is the right entry. */
1363                         nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
1364                                                    device_match_name);
1365                         if (IS_ERR(nvmem)) {
1366                                 /* Provider may not be registered yet. */
1367                                 cell = ERR_CAST(nvmem);
1368                                 break;
1369                         }
1370
1371                         cell_entry = nvmem_find_cell_entry_by_name(nvmem,
1372                                                                    lookup->cell_name);
1373                         if (!cell_entry) {
1374                                 __nvmem_device_put(nvmem);
1375                                 cell = ERR_PTR(-ENOENT);
1376                         } else {
1377                                 cell = nvmem_create_cell(cell_entry, con_id, 0);
1378                                 if (IS_ERR(cell))
1379                                         __nvmem_device_put(nvmem);
1380                         }
1381                         break;
1382                 }
1383         }
1384
1385         mutex_unlock(&nvmem_lookup_mutex);
1386         return cell;
1387 }
1388
1389 static void nvmem_layout_module_put(struct nvmem_device *nvmem)
1390 {
1391         if (nvmem->layout && nvmem->layout->dev.driver)
1392                 module_put(nvmem->layout->dev.driver->owner);
1393 }
1394
1395 #if IS_ENABLED(CONFIG_OF)
1396 static struct nvmem_cell_entry *
1397 nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
1398 {
1399         struct nvmem_cell_entry *iter, *cell = NULL;
1400
1401         mutex_lock(&nvmem_mutex);
1402         list_for_each_entry(iter, &nvmem->cells, node) {
1403                 if (np == iter->np) {
1404                         cell = iter;
1405                         break;
1406                 }
1407         }
1408         mutex_unlock(&nvmem_mutex);
1409
1410         return cell;
1411 }
1412
1413 static int nvmem_layout_module_get_optional(struct nvmem_device *nvmem)
1414 {
1415         if (!nvmem->layout)
1416                 return 0;
1417
1418         if (!nvmem->layout->dev.driver ||
1419             !try_module_get(nvmem->layout->dev.driver->owner))
1420                 return -EPROBE_DEFER;
1421
1422         return 0;
1423 }
1424
1425 /**
1426  * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
1427  *
1428  * @np: Device tree node that uses the nvmem cell.
1429  * @id: nvmem cell name from nvmem-cell-names property, or NULL
1430  *      for the cell at index 0 (the lone cell with no accompanying
1431  *      nvmem-cell-names property).
1432  *
1433  * Return: Will be an ERR_PTR() on error or a valid pointer
1434  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1435  * nvmem_cell_put().
1436  */
1437 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
1438 {
1439         struct device_node *cell_np, *nvmem_np;
1440         struct nvmem_device *nvmem;
1441         struct nvmem_cell_entry *cell_entry;
1442         struct nvmem_cell *cell;
1443         struct of_phandle_args cell_spec;
1444         int index = 0;
1445         int cell_index = 0;
1446         int ret;
1447
1448         /* if cell name exists, find index to the name */
1449         if (id)
1450                 index = of_property_match_string(np, "nvmem-cell-names", id);
1451
1452         ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
1453                                                   "#nvmem-cell-cells",
1454                                                   index, &cell_spec);
1455         if (ret)
1456                 return ERR_PTR(-ENOENT);
1457
1458         if (cell_spec.args_count > 1)
1459                 return ERR_PTR(-EINVAL);
1460
1461         cell_np = cell_spec.np;
1462         if (cell_spec.args_count)
1463                 cell_index = cell_spec.args[0];
1464
1465         nvmem_np = of_get_parent(cell_np);
1466         if (!nvmem_np) {
1467                 of_node_put(cell_np);
1468                 return ERR_PTR(-EINVAL);
1469         }
1470
1471         /* nvmem layouts produce cells within the nvmem-layout container */
1472         if (of_node_name_eq(nvmem_np, "nvmem-layout")) {
1473                 nvmem_np = of_get_next_parent(nvmem_np);
1474                 if (!nvmem_np) {
1475                         of_node_put(cell_np);
1476                         return ERR_PTR(-EINVAL);
1477                 }
1478         }
1479
1480         nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1481         of_node_put(nvmem_np);
1482         if (IS_ERR(nvmem)) {
1483                 of_node_put(cell_np);
1484                 return ERR_CAST(nvmem);
1485         }
1486
1487         ret = nvmem_layout_module_get_optional(nvmem);
1488         if (ret) {
1489                 of_node_put(cell_np);
1490                 __nvmem_device_put(nvmem);
1491                 return ERR_PTR(ret);
1492         }
1493
1494         cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
1495         of_node_put(cell_np);
1496         if (!cell_entry) {
1497                 __nvmem_device_put(nvmem);
1498                 nvmem_layout_module_put(nvmem);
1499                 if (nvmem->layout)
1500                         return ERR_PTR(-EPROBE_DEFER);
1501                 else
1502                         return ERR_PTR(-ENOENT);
1503         }
1504
1505         cell = nvmem_create_cell(cell_entry, id, cell_index);
1506         if (IS_ERR(cell)) {
1507                 __nvmem_device_put(nvmem);
1508                 nvmem_layout_module_put(nvmem);
1509         }
1510
1511         return cell;
1512 }
1513 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
1514 #endif
1515
1516 /**
1517  * nvmem_cell_get() - Get nvmem cell of device form a given cell name
1518  *
1519  * @dev: Device that requests the nvmem cell.
1520  * @id: nvmem cell name to get (this corresponds with the name from the
1521  *      nvmem-cell-names property for DT systems and with the con_id from
1522  *      the lookup entry for non-DT systems).
1523  *
1524  * Return: Will be an ERR_PTR() on error or a valid pointer
1525  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1526  * nvmem_cell_put().
1527  */
1528 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
1529 {
1530         struct nvmem_cell *cell;
1531
1532         if (dev->of_node) { /* try dt first */
1533                 cell = of_nvmem_cell_get(dev->of_node, id);
1534                 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
1535                         return cell;
1536         }
1537
1538         /* NULL cell id only allowed for device tree; invalid otherwise */
1539         if (!id)
1540                 return ERR_PTR(-EINVAL);
1541
1542         return nvmem_cell_get_from_lookup(dev, id);
1543 }
1544 EXPORT_SYMBOL_GPL(nvmem_cell_get);
1545
1546 static void devm_nvmem_cell_release(struct device *dev, void *res)
1547 {
1548         nvmem_cell_put(*(struct nvmem_cell **)res);
1549 }
1550
1551 /**
1552  * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
1553  *
1554  * @dev: Device that requests the nvmem cell.
1555  * @id: nvmem cell name id to get.
1556  *
1557  * Return: Will be an ERR_PTR() on error or a valid pointer
1558  * to a struct nvmem_cell.  The nvmem_cell will be freed by the
1559  * automatically once the device is freed.
1560  */
1561 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
1562 {
1563         struct nvmem_cell **ptr, *cell;
1564
1565         ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
1566         if (!ptr)
1567                 return ERR_PTR(-ENOMEM);
1568
1569         cell = nvmem_cell_get(dev, id);
1570         if (!IS_ERR(cell)) {
1571                 *ptr = cell;
1572                 devres_add(dev, ptr);
1573         } else {
1574                 devres_free(ptr);
1575         }
1576
1577         return cell;
1578 }
1579 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
1580
1581 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
1582 {
1583         struct nvmem_cell **c = res;
1584
1585         if (WARN_ON(!c || !*c))
1586                 return 0;
1587
1588         return *c == data;
1589 }
1590
1591 /**
1592  * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1593  * from devm_nvmem_cell_get.
1594  *
1595  * @dev: Device that requests the nvmem cell.
1596  * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1597  */
1598 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1599 {
1600         int ret;
1601
1602         ret = devres_release(dev, devm_nvmem_cell_release,
1603                                 devm_nvmem_cell_match, cell);
1604
1605         WARN_ON(ret);
1606 }
1607 EXPORT_SYMBOL(devm_nvmem_cell_put);
1608
1609 /**
1610  * nvmem_cell_put() - Release previously allocated nvmem cell.
1611  *
1612  * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1613  */
1614 void nvmem_cell_put(struct nvmem_cell *cell)
1615 {
1616         struct nvmem_device *nvmem = cell->entry->nvmem;
1617
1618         if (cell->id)
1619                 kfree_const(cell->id);
1620
1621         kfree(cell);
1622         __nvmem_device_put(nvmem);
1623         nvmem_layout_module_put(nvmem);
1624 }
1625 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1626
1627 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
1628 {
1629         u8 *p, *b;
1630         int i, extra, bit_offset = cell->bit_offset;
1631
1632         p = b = buf;
1633         if (bit_offset) {
1634                 /* First shift */
1635                 *b++ >>= bit_offset;
1636
1637                 /* setup rest of the bytes if any */
1638                 for (i = 1; i < cell->bytes; i++) {
1639                         /* Get bits from next byte and shift them towards msb */
1640                         *p |= *b << (BITS_PER_BYTE - bit_offset);
1641
1642                         p = b;
1643                         *b++ >>= bit_offset;
1644                 }
1645         } else {
1646                 /* point to the msb */
1647                 p += cell->bytes - 1;
1648         }
1649
1650         /* result fits in less bytes */
1651         extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1652         while (--extra >= 0)
1653                 *p-- = 0;
1654
1655         /* clear msb bits if any leftover in the last byte */
1656         if (cell->nbits % BITS_PER_BYTE)
1657                 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1658 }
1659
1660 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1661                              struct nvmem_cell_entry *cell,
1662                              void *buf, size_t *len, const char *id, int index)
1663 {
1664         int rc;
1665
1666         rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len);
1667
1668         if (rc)
1669                 return rc;
1670
1671         /* shift bits in-place */
1672         if (cell->bit_offset || cell->nbits)
1673                 nvmem_shift_read_buffer_in_place(cell, buf);
1674
1675         if (cell->read_post_process) {
1676                 rc = cell->read_post_process(cell->priv, id, index,
1677                                              cell->offset, buf, cell->raw_len);
1678                 if (rc)
1679                         return rc;
1680         }
1681
1682         if (len)
1683                 *len = cell->bytes;
1684
1685         return 0;
1686 }
1687
1688 /**
1689  * nvmem_cell_read() - Read a given nvmem cell
1690  *
1691  * @cell: nvmem cell to be read.
1692  * @len: pointer to length of cell which will be populated on successful read;
1693  *       can be NULL.
1694  *
1695  * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1696  * buffer should be freed by the consumer with a kfree().
1697  */
1698 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1699 {
1700         struct nvmem_cell_entry *entry = cell->entry;
1701         struct nvmem_device *nvmem = entry->nvmem;
1702         u8 *buf;
1703         int rc;
1704
1705         if (!nvmem)
1706                 return ERR_PTR(-EINVAL);
1707
1708         buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL);
1709         if (!buf)
1710                 return ERR_PTR(-ENOMEM);
1711
1712         rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index);
1713         if (rc) {
1714                 kfree(buf);
1715                 return ERR_PTR(rc);
1716         }
1717
1718         return buf;
1719 }
1720 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1721
1722 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
1723                                              u8 *_buf, int len)
1724 {
1725         struct nvmem_device *nvmem = cell->nvmem;
1726         int i, rc, nbits, bit_offset = cell->bit_offset;
1727         u8 v, *p, *buf, *b, pbyte, pbits;
1728
1729         nbits = cell->nbits;
1730         buf = kzalloc(cell->bytes, GFP_KERNEL);
1731         if (!buf)
1732                 return ERR_PTR(-ENOMEM);
1733
1734         memcpy(buf, _buf, len);
1735         p = b = buf;
1736
1737         if (bit_offset) {
1738                 pbyte = *b;
1739                 *b <<= bit_offset;
1740
1741                 /* setup the first byte with lsb bits from nvmem */
1742                 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1743                 if (rc)
1744                         goto err;
1745                 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1746
1747                 /* setup rest of the byte if any */
1748                 for (i = 1; i < cell->bytes; i++) {
1749                         /* Get last byte bits and shift them towards lsb */
1750                         pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1751                         pbyte = *b;
1752                         p = b;
1753                         *b <<= bit_offset;
1754                         *b++ |= pbits;
1755                 }
1756         }
1757
1758         /* if it's not end on byte boundary */
1759         if ((nbits + bit_offset) % BITS_PER_BYTE) {
1760                 /* setup the last byte with msb bits from nvmem */
1761                 rc = nvmem_reg_read(nvmem,
1762                                     cell->offset + cell->bytes - 1, &v, 1);
1763                 if (rc)
1764                         goto err;
1765                 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1766
1767         }
1768
1769         return buf;
1770 err:
1771         kfree(buf);
1772         return ERR_PTR(rc);
1773 }
1774
1775 static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
1776 {
1777         struct nvmem_device *nvmem = cell->nvmem;
1778         int rc;
1779
1780         if (!nvmem || nvmem->read_only ||
1781             (cell->bit_offset == 0 && len != cell->bytes))
1782                 return -EINVAL;
1783
1784         /*
1785          * Any cells which have a read_post_process hook are read-only because
1786          * we cannot reverse the operation and it might affect other cells,
1787          * too.
1788          */
1789         if (cell->read_post_process)
1790                 return -EINVAL;
1791
1792         if (cell->bit_offset || cell->nbits) {
1793                 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1794                 if (IS_ERR(buf))
1795                         return PTR_ERR(buf);
1796         }
1797
1798         rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1799
1800         /* free the tmp buffer */
1801         if (cell->bit_offset || cell->nbits)
1802                 kfree(buf);
1803
1804         if (rc)
1805                 return rc;
1806
1807         return len;
1808 }
1809
1810 /**
1811  * nvmem_cell_write() - Write to a given nvmem cell
1812  *
1813  * @cell: nvmem cell to be written.
1814  * @buf: Buffer to be written.
1815  * @len: length of buffer to be written to nvmem cell.
1816  *
1817  * Return: length of bytes written or negative on failure.
1818  */
1819 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1820 {
1821         return __nvmem_cell_entry_write(cell->entry, buf, len);
1822 }
1823
1824 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1825
1826 static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
1827                                   void *val, size_t count)
1828 {
1829         struct nvmem_cell *cell;
1830         void *buf;
1831         size_t len;
1832
1833         cell = nvmem_cell_get(dev, cell_id);
1834         if (IS_ERR(cell))
1835                 return PTR_ERR(cell);
1836
1837         buf = nvmem_cell_read(cell, &len);
1838         if (IS_ERR(buf)) {
1839                 nvmem_cell_put(cell);
1840                 return PTR_ERR(buf);
1841         }
1842         if (len != count) {
1843                 kfree(buf);
1844                 nvmem_cell_put(cell);
1845                 return -EINVAL;
1846         }
1847         memcpy(val, buf, count);
1848         kfree(buf);
1849         nvmem_cell_put(cell);
1850
1851         return 0;
1852 }
1853
1854 /**
1855  * nvmem_cell_read_u8() - Read a cell value as a u8
1856  *
1857  * @dev: Device that requests the nvmem cell.
1858  * @cell_id: Name of nvmem cell to read.
1859  * @val: pointer to output value.
1860  *
1861  * Return: 0 on success or negative errno.
1862  */
1863 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
1864 {
1865         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1866 }
1867 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);
1868
1869 /**
1870  * nvmem_cell_read_u16() - Read a cell value as a u16
1871  *
1872  * @dev: Device that requests the nvmem cell.
1873  * @cell_id: Name of nvmem cell to read.
1874  * @val: pointer to output value.
1875  *
1876  * Return: 0 on success or negative errno.
1877  */
1878 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1879 {
1880         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1881 }
1882 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1883
1884 /**
1885  * nvmem_cell_read_u32() - Read a cell value as a u32
1886  *
1887  * @dev: Device that requests the nvmem cell.
1888  * @cell_id: Name of nvmem cell to read.
1889  * @val: pointer to output value.
1890  *
1891  * Return: 0 on success or negative errno.
1892  */
1893 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1894 {
1895         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1896 }
1897 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1898
1899 /**
1900  * nvmem_cell_read_u64() - Read a cell value as a u64
1901  *
1902  * @dev: Device that requests the nvmem cell.
1903  * @cell_id: Name of nvmem cell to read.
1904  * @val: pointer to output value.
1905  *
1906  * Return: 0 on success or negative errno.
1907  */
1908 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
1909 {
1910         return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1911 }
1912 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);
1913
1914 static const void *nvmem_cell_read_variable_common(struct device *dev,
1915                                                    const char *cell_id,
1916                                                    size_t max_len, size_t *len)
1917 {
1918         struct nvmem_cell *cell;
1919         int nbits;
1920         void *buf;
1921
1922         cell = nvmem_cell_get(dev, cell_id);
1923         if (IS_ERR(cell))
1924                 return cell;
1925
1926         nbits = cell->entry->nbits;
1927         buf = nvmem_cell_read(cell, len);
1928         nvmem_cell_put(cell);
1929         if (IS_ERR(buf))
1930                 return buf;
1931
1932         /*
1933          * If nbits is set then nvmem_cell_read() can significantly exaggerate
1934          * the length of the real data. Throw away the extra junk.
1935          */
1936         if (nbits)
1937                 *len = DIV_ROUND_UP(nbits, 8);
1938
1939         if (*len > max_len) {
1940                 kfree(buf);
1941                 return ERR_PTR(-ERANGE);
1942         }
1943
1944         return buf;
1945 }
1946
1947 /**
1948  * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
1949  *
1950  * @dev: Device that requests the nvmem cell.
1951  * @cell_id: Name of nvmem cell to read.
1952  * @val: pointer to output value.
1953  *
1954  * Return: 0 on success or negative errno.
1955  */
1956 int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
1957                                     u32 *val)
1958 {
1959         size_t len;
1960         const u8 *buf;
1961         int i;
1962
1963         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1964         if (IS_ERR(buf))
1965                 return PTR_ERR(buf);
1966
1967         /* Copy w/ implicit endian conversion */
1968         *val = 0;
1969         for (i = 0; i < len; i++)
1970                 *val |= buf[i] << (8 * i);
1971
1972         kfree(buf);
1973
1974         return 0;
1975 }
1976 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);
1977
1978 /**
1979  * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
1980  *
1981  * @dev: Device that requests the nvmem cell.
1982  * @cell_id: Name of nvmem cell to read.
1983  * @val: pointer to output value.
1984  *
1985  * Return: 0 on success or negative errno.
1986  */
1987 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
1988                                     u64 *val)
1989 {
1990         size_t len;
1991         const u8 *buf;
1992         int i;
1993
1994         buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1995         if (IS_ERR(buf))
1996                 return PTR_ERR(buf);
1997
1998         /* Copy w/ implicit endian conversion */
1999         *val = 0;
2000         for (i = 0; i < len; i++)
2001                 *val |= (uint64_t)buf[i] << (8 * i);
2002
2003         kfree(buf);
2004
2005         return 0;
2006 }
2007 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);
2008
2009 /**
2010  * nvmem_device_cell_read() - Read a given nvmem device and cell
2011  *
2012  * @nvmem: nvmem device to read from.
2013  * @info: nvmem cell info to be read.
2014  * @buf: buffer pointer which will be populated on successful read.
2015  *
2016  * Return: length of successful bytes read on success and negative
2017  * error code on error.
2018  */
2019 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
2020                            struct nvmem_cell_info *info, void *buf)
2021 {
2022         struct nvmem_cell_entry cell;
2023         int rc;
2024         ssize_t len;
2025
2026         if (!nvmem)
2027                 return -EINVAL;
2028
2029         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
2030         if (rc)
2031                 return rc;
2032
2033         rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0);
2034         if (rc)
2035                 return rc;
2036
2037         return len;
2038 }
2039 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
2040
2041 /**
2042  * nvmem_device_cell_write() - Write cell to a given nvmem device
2043  *
2044  * @nvmem: nvmem device to be written to.
2045  * @info: nvmem cell info to be written.
2046  * @buf: buffer to be written to cell.
2047  *
2048  * Return: length of bytes written or negative error code on failure.
2049  */
2050 int nvmem_device_cell_write(struct nvmem_device *nvmem,
2051                             struct nvmem_cell_info *info, void *buf)
2052 {
2053         struct nvmem_cell_entry cell;
2054         int rc;
2055
2056         if (!nvmem)
2057                 return -EINVAL;
2058
2059         rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
2060         if (rc)
2061                 return rc;
2062
2063         return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
2064 }
2065 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
2066
2067 /**
2068  * nvmem_device_read() - Read from a given nvmem device
2069  *
2070  * @nvmem: nvmem device to read from.
2071  * @offset: offset in nvmem device.
2072  * @bytes: number of bytes to read.
2073  * @buf: buffer pointer which will be populated on successful read.
2074  *
2075  * Return: length of successful bytes read on success and negative
2076  * error code on error.
2077  */
2078 int nvmem_device_read(struct nvmem_device *nvmem,
2079                       unsigned int offset,
2080                       size_t bytes, void *buf)
2081 {
2082         int rc;
2083
2084         if (!nvmem)
2085                 return -EINVAL;
2086
2087         rc = nvmem_reg_read(nvmem, offset, buf, bytes);
2088
2089         if (rc)
2090                 return rc;
2091
2092         return bytes;
2093 }
2094 EXPORT_SYMBOL_GPL(nvmem_device_read);
2095
2096 /**
2097  * nvmem_device_write() - Write cell to a given nvmem device
2098  *
2099  * @nvmem: nvmem device to be written to.
2100  * @offset: offset in nvmem device.
2101  * @bytes: number of bytes to write.
2102  * @buf: buffer to be written.
2103  *
2104  * Return: length of bytes written or negative error code on failure.
2105  */
2106 int nvmem_device_write(struct nvmem_device *nvmem,
2107                        unsigned int offset,
2108                        size_t bytes, void *buf)
2109 {
2110         int rc;
2111
2112         if (!nvmem)
2113                 return -EINVAL;
2114
2115         rc = nvmem_reg_write(nvmem, offset, buf, bytes);
2116
2117         if (rc)
2118                 return rc;
2119
2120
2121         return bytes;
2122 }
2123 EXPORT_SYMBOL_GPL(nvmem_device_write);
2124
2125 /**
2126  * nvmem_add_cell_table() - register a table of cell info entries
2127  *
2128  * @table: table of cell info entries
2129  */
2130 void nvmem_add_cell_table(struct nvmem_cell_table *table)
2131 {
2132         mutex_lock(&nvmem_cell_mutex);
2133         list_add_tail(&table->node, &nvmem_cell_tables);
2134         mutex_unlock(&nvmem_cell_mutex);
2135 }
2136 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
2137
2138 /**
2139  * nvmem_del_cell_table() - remove a previously registered cell info table
2140  *
2141  * @table: table of cell info entries
2142  */
2143 void nvmem_del_cell_table(struct nvmem_cell_table *table)
2144 {
2145         mutex_lock(&nvmem_cell_mutex);
2146         list_del(&table->node);
2147         mutex_unlock(&nvmem_cell_mutex);
2148 }
2149 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
2150
2151 /**
2152  * nvmem_add_cell_lookups() - register a list of cell lookup entries
2153  *
2154  * @entries: array of cell lookup entries
2155  * @nentries: number of cell lookup entries in the array
2156  */
2157 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2158 {
2159         int i;
2160
2161         mutex_lock(&nvmem_lookup_mutex);
2162         for (i = 0; i < nentries; i++)
2163                 list_add_tail(&entries[i].node, &nvmem_lookup_list);
2164         mutex_unlock(&nvmem_lookup_mutex);
2165 }
2166 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
2167
2168 /**
2169  * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
2170  *                            entries
2171  *
2172  * @entries: array of cell lookup entries
2173  * @nentries: number of cell lookup entries in the array
2174  */
2175 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
2176 {
2177         int i;
2178
2179         mutex_lock(&nvmem_lookup_mutex);
2180         for (i = 0; i < nentries; i++)
2181                 list_del(&entries[i].node);
2182         mutex_unlock(&nvmem_lookup_mutex);
2183 }
2184 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
2185
2186 /**
2187  * nvmem_dev_name() - Get the name of a given nvmem device.
2188  *
2189  * @nvmem: nvmem device.
2190  *
2191  * Return: name of the nvmem device.
2192  */
2193 const char *nvmem_dev_name(struct nvmem_device *nvmem)
2194 {
2195         return dev_name(&nvmem->dev);
2196 }
2197 EXPORT_SYMBOL_GPL(nvmem_dev_name);
2198
2199 /**
2200  * nvmem_dev_size() - Get the size of a given nvmem device.
2201  *
2202  * @nvmem: nvmem device.
2203  *
2204  * Return: size of the nvmem device.
2205  */
2206 size_t nvmem_dev_size(struct nvmem_device *nvmem)
2207 {
2208         return nvmem->size;
2209 }
2210 EXPORT_SYMBOL_GPL(nvmem_dev_size);
2211
2212 static int __init nvmem_init(void)
2213 {
2214         int ret;
2215
2216         ret = bus_register(&nvmem_bus_type);
2217         if (ret)
2218                 return ret;
2219
2220         ret = nvmem_layout_bus_register();
2221         if (ret)
2222                 bus_unregister(&nvmem_bus_type);
2223
2224         return ret;
2225 }
2226
2227 static void __exit nvmem_exit(void)
2228 {
2229         nvmem_layout_bus_unregister();
2230         bus_unregister(&nvmem_bus_type);
2231 }
2232
2233 subsys_initcall(nvmem_init);
2234 module_exit(nvmem_exit);
2235
2236 MODULE_AUTHOR("Srinivas Kandagatla <[email protected]");
2237 MODULE_AUTHOR("Maxime Ripard <[email protected]");
2238 MODULE_DESCRIPTION("nvmem Driver Core");