1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * nvmem framework core. 4 * 5 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> 6 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> 7 */ 8 9 #include <linux/device.h> 10 #include <linux/export.h> 11 #include <linux/fs.h> 12 #include <linux/idr.h> 13 #include <linux/init.h> 14 #include <linux/kref.h> 15 #include <linux/module.h> 16 #include <linux/nvmem-consumer.h> 17 #include <linux/nvmem-provider.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/of.h> 20 #include <linux/slab.h> 21 22 #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 sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]); 183 } 184 185 static DEVICE_ATTR_RO(type); 186 187 static struct attribute *nvmem_attrs[] = { 188 &dev_attr_type.attr, 189 NULL, 190 }; 191 192 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj, 193 struct bin_attribute *attr, char *buf, 194 loff_t pos, size_t count) 195 { 196 struct device *dev; 197 struct nvmem_device *nvmem; 198 int rc; 199 200 if (attr->private) 201 dev = attr->private; 202 else 203 dev = kobj_to_dev(kobj); 204 nvmem = to_nvmem_device(dev); 205 206 /* Stop the user from reading */ 207 if (pos >= nvmem->size) 208 return 0; 209 210 if (!IS_ALIGNED(pos, nvmem->stride)) 211 return -EINVAL; 212 213 if (count < nvmem->word_size) 214 return -EINVAL; 215 216 if (pos + count > nvmem->size) 217 count = nvmem->size - pos; 218 219 count = round_down(count, nvmem->word_size); 220 221 if (!nvmem->reg_read) 222 return -EPERM; 223 224 rc = nvmem_reg_read(nvmem, pos, buf, count); 225 226 if (rc) 227 return rc; 228 229 return count; 230 } 231 232 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, 233 struct bin_attribute *attr, char *buf, 234 loff_t pos, size_t count) 235 { 236 struct device *dev; 237 struct nvmem_device *nvmem; 238 int rc; 239 240 if (attr->private) 241 dev = attr->private; 242 else 243 dev = kobj_to_dev(kobj); 244 nvmem = to_nvmem_device(dev); 245 246 /* Stop the user from writing */ 247 if (pos >= nvmem->size) 248 return -EFBIG; 249 250 if (!IS_ALIGNED(pos, nvmem->stride)) 251 return -EINVAL; 252 253 if (count < nvmem->word_size) 254 return -EINVAL; 255 256 if (pos + count > nvmem->size) 257 count = nvmem->size - pos; 258 259 count = round_down(count, nvmem->word_size); 260 261 if (!nvmem->reg_write) 262 return -EPERM; 263 264 rc = nvmem_reg_write(nvmem, pos, buf, count); 265 266 if (rc) 267 return rc; 268 269 return count; 270 } 271 272 static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem) 273 { 274 umode_t mode = 0400; 275 276 if (!nvmem->root_only) 277 mode |= 0044; 278 279 if (!nvmem->read_only) 280 mode |= 0200; 281 282 if (!nvmem->reg_write) 283 mode &= ~0200; 284 285 if (!nvmem->reg_read) 286 mode &= ~0444; 287 288 return mode; 289 } 290 291 static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj, 292 struct bin_attribute *attr, int i) 293 { 294 struct device *dev = kobj_to_dev(kobj); 295 struct nvmem_device *nvmem = to_nvmem_device(dev); 296 297 attr->size = nvmem->size; 298 299 return nvmem_bin_attr_get_umode(nvmem); 300 } 301 302 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, 303 const char *id, int index); 304 305 static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj, 306 struct bin_attribute *attr, char *buf, 307 loff_t pos, size_t count) 308 { 309 struct nvmem_cell_entry *entry; 310 struct nvmem_cell *cell = NULL; 311 size_t cell_sz, read_len; 312 void *content; 313 314 entry = attr->private; 315 cell = nvmem_create_cell(entry, entry->name, 0); 316 if (IS_ERR(cell)) 317 return PTR_ERR(cell); 318 319 if (!cell) 320 return -EINVAL; 321 322 content = nvmem_cell_read(cell, &cell_sz); 323 if (IS_ERR(content)) { 324 read_len = PTR_ERR(content); 325 goto destroy_cell; 326 } 327 328 read_len = min_t(unsigned int, cell_sz - pos, count); 329 memcpy(buf, content + pos, read_len); 330 kfree(content); 331 332 destroy_cell: 333 kfree_const(cell->id); 334 kfree(cell); 335 336 return read_len; 337 } 338 339 /* default read/write permissions */ 340 static struct bin_attribute bin_attr_rw_nvmem = { 341 .attr = { 342 .name = "nvmem", 343 .mode = 0644, 344 }, 345 .read = bin_attr_nvmem_read, 346 .write = bin_attr_nvmem_write, 347 }; 348 349 static struct bin_attribute *nvmem_bin_attributes[] = { 350 &bin_attr_rw_nvmem, 351 NULL, 352 }; 353 354 static const struct attribute_group nvmem_bin_group = { 355 .bin_attrs = nvmem_bin_attributes, 356 .attrs = nvmem_attrs, 357 .is_bin_visible = nvmem_bin_attr_is_visible, 358 }; 359 360 /* Cell attributes will be dynamically allocated */ 361 static struct attribute_group nvmem_cells_group = { 362 .name = "cells", 363 }; 364 365 static const struct attribute_group *nvmem_dev_groups[] = { 366 &nvmem_bin_group, 367 NULL, 368 }; 369 370 static const struct attribute_group *nvmem_cells_groups[] = { 371 &nvmem_cells_group, 372 NULL, 373 }; 374 375 static struct bin_attribute bin_attr_nvmem_eeprom_compat = { 376 .attr = { 377 .name = "eeprom", 378 }, 379 .read = bin_attr_nvmem_read, 380 .write = bin_attr_nvmem_write, 381 }; 382 383 /* 384 * nvmem_setup_compat() - Create an additional binary entry in 385 * drivers sys directory, to be backwards compatible with the older 386 * drivers/misc/eeprom drivers. 387 */ 388 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, 389 const struct nvmem_config *config) 390 { 391 int rval; 392 393 if (!config->compat) 394 return 0; 395 396 if (!config->base_dev) 397 return -EINVAL; 398 399 if (config->type == NVMEM_TYPE_FRAM) 400 bin_attr_nvmem_eeprom_compat.attr.name = "fram"; 401 402 nvmem->eeprom = bin_attr_nvmem_eeprom_compat; 403 nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem); 404 nvmem->eeprom.size = nvmem->size; 405 #ifdef CONFIG_DEBUG_LOCK_ALLOC 406 nvmem->eeprom.attr.key = &eeprom_lock_key; 407 #endif 408 nvmem->eeprom.private = &nvmem->dev; 409 nvmem->base_dev = config->base_dev; 410 411 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom); 412 if (rval) { 413 dev_err(&nvmem->dev, 414 "Failed to create eeprom binary file %d\n", rval); 415 return rval; 416 } 417 418 nvmem->flags |= FLAG_COMPAT; 419 420 return 0; 421 } 422 423 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, 424 const struct nvmem_config *config) 425 { 426 if (config->compat) 427 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); 428 } 429 430 static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) 431 { 432 struct bin_attribute **cells_attrs, *attrs; 433 struct nvmem_cell_entry *entry; 434 unsigned int ncells = 0, i = 0; 435 int ret = 0; 436 437 mutex_lock(&nvmem_mutex); 438 439 if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated) { 440 nvmem_cells_group.bin_attrs = NULL; 441 goto unlock_mutex; 442 } 443 444 /* Allocate an array of attributes with a sentinel */ 445 ncells = list_count_nodes(&nvmem->cells); 446 cells_attrs = devm_kcalloc(&nvmem->dev, ncells + 1, 447 sizeof(struct bin_attribute *), GFP_KERNEL); 448 if (!cells_attrs) { 449 ret = -ENOMEM; 450 goto unlock_mutex; 451 } 452 453 attrs = devm_kcalloc(&nvmem->dev, ncells, sizeof(struct bin_attribute), GFP_KERNEL); 454 if (!attrs) { 455 ret = -ENOMEM; 456 goto unlock_mutex; 457 } 458 459 /* Initialize each attribute to take the name and size of the cell */ 460 list_for_each_entry(entry, &nvmem->cells, node) { 461 sysfs_bin_attr_init(&attrs[i]); 462 attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL, 463 "%s@%x", entry->name, 464 entry->offset); 465 attrs[i].attr.mode = 0444; 466 attrs[i].size = entry->bytes; 467 attrs[i].read = &nvmem_cell_attr_read; 468 attrs[i].private = entry; 469 if (!attrs[i].attr.name) { 470 ret = -ENOMEM; 471 goto unlock_mutex; 472 } 473 474 cells_attrs[i] = &attrs[i]; 475 i++; 476 } 477 478 nvmem_cells_group.bin_attrs = cells_attrs; 479 480 ret = devm_device_add_groups(&nvmem->dev, nvmem_cells_groups); 481 if (ret) 482 goto unlock_mutex; 483 484 nvmem->sysfs_cells_populated = true; 485 486 unlock_mutex: 487 mutex_unlock(&nvmem_mutex); 488 489 return ret; 490 } 491 492 #else /* CONFIG_NVMEM_SYSFS */ 493 494 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, 495 const struct nvmem_config *config) 496 { 497 return -ENOSYS; 498 } 499 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, 500 const struct nvmem_config *config) 501 { 502 } 503 504 #endif /* CONFIG_NVMEM_SYSFS */ 505 506 static void nvmem_release(struct device *dev) 507 { 508 struct nvmem_device *nvmem = to_nvmem_device(dev); 509 510 ida_free(&nvmem_ida, nvmem->id); 511 gpiod_put(nvmem->wp_gpio); 512 kfree(nvmem); 513 } 514 515 static const struct device_type nvmem_provider_type = { 516 .release = nvmem_release, 517 }; 518 519 static struct bus_type nvmem_bus_type = { 520 .name = "nvmem", 521 }; 522 523 static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell) 524 { 525 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell); 526 mutex_lock(&nvmem_mutex); 527 list_del(&cell->node); 528 mutex_unlock(&nvmem_mutex); 529 of_node_put(cell->np); 530 kfree_const(cell->name); 531 kfree(cell); 532 } 533 534 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem) 535 { 536 struct nvmem_cell_entry *cell, *p; 537 538 list_for_each_entry_safe(cell, p, &nvmem->cells, node) 539 nvmem_cell_entry_drop(cell); 540 } 541 542 static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell) 543 { 544 mutex_lock(&nvmem_mutex); 545 list_add_tail(&cell->node, &cell->nvmem->cells); 546 mutex_unlock(&nvmem_mutex); 547 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell); 548 } 549 550 static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem, 551 const struct nvmem_cell_info *info, 552 struct nvmem_cell_entry *cell) 553 { 554 cell->nvmem = nvmem; 555 cell->offset = info->offset; 556 cell->raw_len = info->raw_len ?: info->bytes; 557 cell->bytes = info->bytes; 558 cell->name = info->name; 559 cell->read_post_process = info->read_post_process; 560 cell->priv = info->priv; 561 562 cell->bit_offset = info->bit_offset; 563 cell->nbits = info->nbits; 564 cell->np = info->np; 565 566 if (cell->nbits) 567 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset, 568 BITS_PER_BYTE); 569 570 if (!IS_ALIGNED(cell->offset, nvmem->stride)) { 571 dev_err(&nvmem->dev, 572 "cell %s unaligned to nvmem stride %d\n", 573 cell->name ?: "<unknown>", nvmem->stride); 574 return -EINVAL; 575 } 576 577 return 0; 578 } 579 580 static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem, 581 const struct nvmem_cell_info *info, 582 struct nvmem_cell_entry *cell) 583 { 584 int err; 585 586 err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell); 587 if (err) 588 return err; 589 590 cell->name = kstrdup_const(info->name, GFP_KERNEL); 591 if (!cell->name) 592 return -ENOMEM; 593 594 return 0; 595 } 596 597 /** 598 * nvmem_add_one_cell() - Add one cell information to an nvmem device 599 * 600 * @nvmem: nvmem device to add cells to. 601 * @info: nvmem cell info to add to the device 602 * 603 * Return: 0 or negative error code on failure. 604 */ 605 int nvmem_add_one_cell(struct nvmem_device *nvmem, 606 const struct nvmem_cell_info *info) 607 { 608 struct nvmem_cell_entry *cell; 609 int rval; 610 611 cell = kzalloc(sizeof(*cell), GFP_KERNEL); 612 if (!cell) 613 return -ENOMEM; 614 615 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell); 616 if (rval) { 617 kfree(cell); 618 return rval; 619 } 620 621 nvmem_cell_entry_add(cell); 622 623 return 0; 624 } 625 EXPORT_SYMBOL_GPL(nvmem_add_one_cell); 626 627 /** 628 * nvmem_add_cells() - Add cell information to an nvmem device 629 * 630 * @nvmem: nvmem device to add cells to. 631 * @info: nvmem cell info to add to the device 632 * @ncells: number of cells in info 633 * 634 * Return: 0 or negative error code on failure. 635 */ 636 static int nvmem_add_cells(struct nvmem_device *nvmem, 637 const struct nvmem_cell_info *info, 638 int ncells) 639 { 640 int i, rval; 641 642 for (i = 0; i < ncells; i++) { 643 rval = nvmem_add_one_cell(nvmem, &info[i]); 644 if (rval) 645 return rval; 646 } 647 648 return 0; 649 } 650 651 /** 652 * nvmem_register_notifier() - Register a notifier block for nvmem events. 653 * 654 * @nb: notifier block to be called on nvmem events. 655 * 656 * Return: 0 on success, negative error number on failure. 657 */ 658 int nvmem_register_notifier(struct notifier_block *nb) 659 { 660 return blocking_notifier_chain_register(&nvmem_notifier, nb); 661 } 662 EXPORT_SYMBOL_GPL(nvmem_register_notifier); 663 664 /** 665 * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events. 666 * 667 * @nb: notifier block to be unregistered. 668 * 669 * Return: 0 on success, negative error number on failure. 670 */ 671 int nvmem_unregister_notifier(struct notifier_block *nb) 672 { 673 return blocking_notifier_chain_unregister(&nvmem_notifier, nb); 674 } 675 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier); 676 677 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem) 678 { 679 const struct nvmem_cell_info *info; 680 struct nvmem_cell_table *table; 681 struct nvmem_cell_entry *cell; 682 int rval = 0, i; 683 684 mutex_lock(&nvmem_cell_mutex); 685 list_for_each_entry(table, &nvmem_cell_tables, node) { 686 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) { 687 for (i = 0; i < table->ncells; i++) { 688 info = &table->cells[i]; 689 690 cell = kzalloc(sizeof(*cell), GFP_KERNEL); 691 if (!cell) { 692 rval = -ENOMEM; 693 goto out; 694 } 695 696 rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell); 697 if (rval) { 698 kfree(cell); 699 goto out; 700 } 701 702 nvmem_cell_entry_add(cell); 703 } 704 } 705 } 706 707 out: 708 mutex_unlock(&nvmem_cell_mutex); 709 return rval; 710 } 711 712 static struct nvmem_cell_entry * 713 nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id) 714 { 715 struct nvmem_cell_entry *iter, *cell = NULL; 716 717 mutex_lock(&nvmem_mutex); 718 list_for_each_entry(iter, &nvmem->cells, node) { 719 if (strcmp(cell_id, iter->name) == 0) { 720 cell = iter; 721 break; 722 } 723 } 724 mutex_unlock(&nvmem_mutex); 725 726 return cell; 727 } 728 729 static int nvmem_validate_keepouts(struct nvmem_device *nvmem) 730 { 731 unsigned int cur = 0; 732 const struct nvmem_keepout *keepout = nvmem->keepout; 733 const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout; 734 735 while (keepout < keepoutend) { 736 /* Ensure keepouts are sorted and don't overlap. */ 737 if (keepout->start < cur) { 738 dev_err(&nvmem->dev, 739 "Keepout regions aren't sorted or overlap.\n"); 740 741 return -ERANGE; 742 } 743 744 if (keepout->end < keepout->start) { 745 dev_err(&nvmem->dev, 746 "Invalid keepout region.\n"); 747 748 return -EINVAL; 749 } 750 751 /* 752 * Validate keepouts (and holes between) don't violate 753 * word_size constraints. 754 */ 755 if ((keepout->end - keepout->start < nvmem->word_size) || 756 ((keepout->start != cur) && 757 (keepout->start - cur < nvmem->word_size))) { 758 759 dev_err(&nvmem->dev, 760 "Keepout regions violate word_size constraints.\n"); 761 762 return -ERANGE; 763 } 764 765 /* Validate keepouts don't violate stride (alignment). */ 766 if (!IS_ALIGNED(keepout->start, nvmem->stride) || 767 !IS_ALIGNED(keepout->end, nvmem->stride)) { 768 769 dev_err(&nvmem->dev, 770 "Keepout regions violate stride.\n"); 771 772 return -EINVAL; 773 } 774 775 cur = keepout->end; 776 keepout++; 777 } 778 779 return 0; 780 } 781 782 static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np) 783 { 784 struct device *dev = &nvmem->dev; 785 struct device_node *child; 786 const __be32 *addr; 787 int len, ret; 788 789 for_each_child_of_node(np, child) { 790 struct nvmem_cell_info info = {0}; 791 792 addr = of_get_property(child, "reg", &len); 793 if (!addr) 794 continue; 795 if (len < 2 * sizeof(u32)) { 796 dev_err(dev, "nvmem: invalid reg on %pOF\n", child); 797 of_node_put(child); 798 return -EINVAL; 799 } 800 801 info.offset = be32_to_cpup(addr++); 802 info.bytes = be32_to_cpup(addr); 803 info.name = kasprintf(GFP_KERNEL, "%pOFn", child); 804 805 addr = of_get_property(child, "bits", &len); 806 if (addr && len == (2 * sizeof(u32))) { 807 info.bit_offset = be32_to_cpup(addr++); 808 info.nbits = be32_to_cpup(addr); 809 } 810 811 info.np = of_node_get(child); 812 813 if (nvmem->fixup_dt_cell_info) 814 nvmem->fixup_dt_cell_info(nvmem, &info); 815 816 ret = nvmem_add_one_cell(nvmem, &info); 817 kfree(info.name); 818 if (ret) { 819 of_node_put(child); 820 return ret; 821 } 822 } 823 824 return 0; 825 } 826 827 static int nvmem_add_cells_from_legacy_of(struct nvmem_device *nvmem) 828 { 829 return nvmem_add_cells_from_dt(nvmem, nvmem->dev.of_node); 830 } 831 832 static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem) 833 { 834 struct device_node *layout_np; 835 int err = 0; 836 837 layout_np = of_nvmem_layout_get_container(nvmem); 838 if (!layout_np) 839 return 0; 840 841 if (of_device_is_compatible(layout_np, "fixed-layout")) 842 err = nvmem_add_cells_from_dt(nvmem, layout_np); 843 844 of_node_put(layout_np); 845 846 return err; 847 } 848 849 int nvmem_layout_register(struct nvmem_layout *layout) 850 { 851 int ret; 852 853 if (!layout->add_cells) 854 return -EINVAL; 855 856 /* Populate the cells */ 857 ret = layout->add_cells(layout); 858 if (ret) 859 return ret; 860 861 #ifdef CONFIG_NVMEM_SYSFS 862 ret = nvmem_populate_sysfs_cells(layout->nvmem); 863 if (ret) { 864 nvmem_device_remove_all_cells(layout->nvmem); 865 return ret; 866 } 867 #endif 868 869 return 0; 870 } 871 EXPORT_SYMBOL_GPL(nvmem_layout_register); 872 873 void nvmem_layout_unregister(struct nvmem_layout *layout) 874 { 875 /* Keep the API even with an empty stub in case we need it later */ 876 } 877 EXPORT_SYMBOL_GPL(nvmem_layout_unregister); 878 879 /** 880 * nvmem_register() - Register a nvmem device for given nvmem_config. 881 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem 882 * 883 * @config: nvmem device configuration with which nvmem device is created. 884 * 885 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device 886 * on success. 887 */ 888 889 struct nvmem_device *nvmem_register(const struct nvmem_config *config) 890 { 891 struct nvmem_device *nvmem; 892 int rval; 893 894 if (!config->dev) 895 return ERR_PTR(-EINVAL); 896 897 if (!config->reg_read && !config->reg_write) 898 return ERR_PTR(-EINVAL); 899 900 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL); 901 if (!nvmem) 902 return ERR_PTR(-ENOMEM); 903 904 rval = ida_alloc(&nvmem_ida, GFP_KERNEL); 905 if (rval < 0) { 906 kfree(nvmem); 907 return ERR_PTR(rval); 908 } 909 910 nvmem->id = rval; 911 912 nvmem->dev.type = &nvmem_provider_type; 913 nvmem->dev.bus = &nvmem_bus_type; 914 nvmem->dev.parent = config->dev; 915 916 device_initialize(&nvmem->dev); 917 918 if (!config->ignore_wp) 919 nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp", 920 GPIOD_OUT_HIGH); 921 if (IS_ERR(nvmem->wp_gpio)) { 922 rval = PTR_ERR(nvmem->wp_gpio); 923 nvmem->wp_gpio = NULL; 924 goto err_put_device; 925 } 926 927 kref_init(&nvmem->refcnt); 928 INIT_LIST_HEAD(&nvmem->cells); 929 nvmem->fixup_dt_cell_info = config->fixup_dt_cell_info; 930 931 nvmem->owner = config->owner; 932 if (!nvmem->owner && config->dev->driver) 933 nvmem->owner = config->dev->driver->owner; 934 nvmem->stride = config->stride ?: 1; 935 nvmem->word_size = config->word_size ?: 1; 936 nvmem->size = config->size; 937 nvmem->root_only = config->root_only; 938 nvmem->priv = config->priv; 939 nvmem->type = config->type; 940 nvmem->reg_read = config->reg_read; 941 nvmem->reg_write = config->reg_write; 942 nvmem->keepout = config->keepout; 943 nvmem->nkeepout = config->nkeepout; 944 if (config->of_node) 945 nvmem->dev.of_node = config->of_node; 946 else 947 nvmem->dev.of_node = config->dev->of_node; 948 949 switch (config->id) { 950 case NVMEM_DEVID_NONE: 951 rval = dev_set_name(&nvmem->dev, "%s", config->name); 952 break; 953 case NVMEM_DEVID_AUTO: 954 rval = dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id); 955 break; 956 default: 957 rval = dev_set_name(&nvmem->dev, "%s%d", 958 config->name ? : "nvmem", 959 config->name ? config->id : nvmem->id); 960 break; 961 } 962 963 if (rval) 964 goto err_put_device; 965 966 nvmem->read_only = device_property_present(config->dev, "read-only") || 967 config->read_only || !nvmem->reg_write; 968 969 #ifdef CONFIG_NVMEM_SYSFS 970 nvmem->dev.groups = nvmem_dev_groups; 971 #endif 972 973 if (nvmem->nkeepout) { 974 rval = nvmem_validate_keepouts(nvmem); 975 if (rval) 976 goto err_put_device; 977 } 978 979 if (config->compat) { 980 rval = nvmem_sysfs_setup_compat(nvmem, config); 981 if (rval) 982 goto err_put_device; 983 } 984 985 if (config->cells) { 986 rval = nvmem_add_cells(nvmem, config->cells, config->ncells); 987 if (rval) 988 goto err_remove_cells; 989 } 990 991 rval = nvmem_add_cells_from_table(nvmem); 992 if (rval) 993 goto err_remove_cells; 994 995 if (config->add_legacy_fixed_of_cells) { 996 rval = nvmem_add_cells_from_legacy_of(nvmem); 997 if (rval) 998 goto err_remove_cells; 999 } 1000 1001 rval = nvmem_add_cells_from_fixed_layout(nvmem); 1002 if (rval) 1003 goto err_remove_cells; 1004 1005 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); 1006 1007 rval = device_add(&nvmem->dev); 1008 if (rval) 1009 goto err_remove_cells; 1010 1011 rval = nvmem_populate_layout(nvmem); 1012 if (rval) 1013 goto err_remove_dev; 1014 1015 #ifdef CONFIG_NVMEM_SYSFS 1016 rval = nvmem_populate_sysfs_cells(nvmem); 1017 if (rval) 1018 goto err_destroy_layout; 1019 #endif 1020 1021 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem); 1022 1023 return nvmem; 1024 1025 #ifdef CONFIG_NVMEM_SYSFS 1026 err_destroy_layout: 1027 nvmem_destroy_layout(nvmem); 1028 #endif 1029 err_remove_dev: 1030 device_del(&nvmem->dev); 1031 err_remove_cells: 1032 nvmem_device_remove_all_cells(nvmem); 1033 if (config->compat) 1034 nvmem_sysfs_remove_compat(nvmem, config); 1035 err_put_device: 1036 put_device(&nvmem->dev); 1037 1038 return ERR_PTR(rval); 1039 } 1040 EXPORT_SYMBOL_GPL(nvmem_register); 1041 1042 static void nvmem_device_release(struct kref *kref) 1043 { 1044 struct nvmem_device *nvmem; 1045 1046 nvmem = container_of(kref, struct nvmem_device, refcnt); 1047 1048 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem); 1049 1050 if (nvmem->flags & FLAG_COMPAT) 1051 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); 1052 1053 nvmem_device_remove_all_cells(nvmem); 1054 nvmem_destroy_layout(nvmem); 1055 device_unregister(&nvmem->dev); 1056 } 1057 1058 /** 1059 * nvmem_unregister() - Unregister previously registered nvmem device 1060 * 1061 * @nvmem: Pointer to previously registered nvmem device. 1062 */ 1063 void nvmem_unregister(struct nvmem_device *nvmem) 1064 { 1065 if (nvmem) 1066 kref_put(&nvmem->refcnt, nvmem_device_release); 1067 } 1068 EXPORT_SYMBOL_GPL(nvmem_unregister); 1069 1070 static void devm_nvmem_unregister(void *nvmem) 1071 { 1072 nvmem_unregister(nvmem); 1073 } 1074 1075 /** 1076 * devm_nvmem_register() - Register a managed nvmem device for given 1077 * nvmem_config. 1078 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem 1079 * 1080 * @dev: Device that uses the nvmem device. 1081 * @config: nvmem device configuration with which nvmem device is created. 1082 * 1083 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device 1084 * on success. 1085 */ 1086 struct nvmem_device *devm_nvmem_register(struct device *dev, 1087 const struct nvmem_config *config) 1088 { 1089 struct nvmem_device *nvmem; 1090 int ret; 1091 1092 nvmem = nvmem_register(config); 1093 if (IS_ERR(nvmem)) 1094 return nvmem; 1095 1096 ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem); 1097 if (ret) 1098 return ERR_PTR(ret); 1099 1100 return nvmem; 1101 } 1102 EXPORT_SYMBOL_GPL(devm_nvmem_register); 1103 1104 static struct nvmem_device *__nvmem_device_get(void *data, 1105 int (*match)(struct device *dev, const void *data)) 1106 { 1107 struct nvmem_device *nvmem = NULL; 1108 struct device *dev; 1109 1110 mutex_lock(&nvmem_mutex); 1111 dev = bus_find_device(&nvmem_bus_type, NULL, data, match); 1112 if (dev) 1113 nvmem = to_nvmem_device(dev); 1114 mutex_unlock(&nvmem_mutex); 1115 if (!nvmem) 1116 return ERR_PTR(-EPROBE_DEFER); 1117 1118 if (!try_module_get(nvmem->owner)) { 1119 dev_err(&nvmem->dev, 1120 "could not increase module refcount for cell %s\n", 1121 nvmem_dev_name(nvmem)); 1122 1123 put_device(&nvmem->dev); 1124 return ERR_PTR(-EINVAL); 1125 } 1126 1127 kref_get(&nvmem->refcnt); 1128 1129 return nvmem; 1130 } 1131 1132 static void __nvmem_device_put(struct nvmem_device *nvmem) 1133 { 1134 put_device(&nvmem->dev); 1135 module_put(nvmem->owner); 1136 kref_put(&nvmem->refcnt, nvmem_device_release); 1137 } 1138 1139 #if IS_ENABLED(CONFIG_OF) 1140 /** 1141 * of_nvmem_device_get() - Get nvmem device from a given id 1142 * 1143 * @np: Device tree node that uses the nvmem device. 1144 * @id: nvmem name from nvmem-names property. 1145 * 1146 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device 1147 * on success. 1148 */ 1149 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id) 1150 { 1151 1152 struct device_node *nvmem_np; 1153 struct nvmem_device *nvmem; 1154 int index = 0; 1155 1156 if (id) 1157 index = of_property_match_string(np, "nvmem-names", id); 1158 1159 nvmem_np = of_parse_phandle(np, "nvmem", index); 1160 if (!nvmem_np) 1161 return ERR_PTR(-ENOENT); 1162 1163 nvmem = __nvmem_device_get(nvmem_np, device_match_of_node); 1164 of_node_put(nvmem_np); 1165 return nvmem; 1166 } 1167 EXPORT_SYMBOL_GPL(of_nvmem_device_get); 1168 #endif 1169 1170 /** 1171 * nvmem_device_get() - Get nvmem device from a given id 1172 * 1173 * @dev: Device that uses the nvmem device. 1174 * @dev_name: name of the requested nvmem device. 1175 * 1176 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device 1177 * on success. 1178 */ 1179 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name) 1180 { 1181 if (dev->of_node) { /* try dt first */ 1182 struct nvmem_device *nvmem; 1183 1184 nvmem = of_nvmem_device_get(dev->of_node, dev_name); 1185 1186 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER) 1187 return nvmem; 1188 1189 } 1190 1191 return __nvmem_device_get((void *)dev_name, device_match_name); 1192 } 1193 EXPORT_SYMBOL_GPL(nvmem_device_get); 1194 1195 /** 1196 * nvmem_device_find() - Find nvmem device with matching function 1197 * 1198 * @data: Data to pass to match function 1199 * @match: Callback function to check device 1200 * 1201 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device 1202 * on success. 1203 */ 1204 struct nvmem_device *nvmem_device_find(void *data, 1205 int (*match)(struct device *dev, const void *data)) 1206 { 1207 return __nvmem_device_get(data, match); 1208 } 1209 EXPORT_SYMBOL_GPL(nvmem_device_find); 1210 1211 static int devm_nvmem_device_match(struct device *dev, void *res, void *data) 1212 { 1213 struct nvmem_device **nvmem = res; 1214 1215 if (WARN_ON(!nvmem || !*nvmem)) 1216 return 0; 1217 1218 return *nvmem == data; 1219 } 1220 1221 static void devm_nvmem_device_release(struct device *dev, void *res) 1222 { 1223 nvmem_device_put(*(struct nvmem_device **)res); 1224 } 1225 1226 /** 1227 * devm_nvmem_device_put() - put alredy got nvmem device 1228 * 1229 * @dev: Device that uses the nvmem device. 1230 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(), 1231 * that needs to be released. 1232 */ 1233 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem) 1234 { 1235 int ret; 1236 1237 ret = devres_release(dev, devm_nvmem_device_release, 1238 devm_nvmem_device_match, nvmem); 1239 1240 WARN_ON(ret); 1241 } 1242 EXPORT_SYMBOL_GPL(devm_nvmem_device_put); 1243 1244 /** 1245 * nvmem_device_put() - put alredy got nvmem device 1246 * 1247 * @nvmem: pointer to nvmem device that needs to be released. 1248 */ 1249 void nvmem_device_put(struct nvmem_device *nvmem) 1250 { 1251 __nvmem_device_put(nvmem); 1252 } 1253 EXPORT_SYMBOL_GPL(nvmem_device_put); 1254 1255 /** 1256 * devm_nvmem_device_get() - Get nvmem cell of device form a given id 1257 * 1258 * @dev: Device that requests the nvmem device. 1259 * @id: name id for the requested nvmem device. 1260 * 1261 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell 1262 * on success. The nvmem_cell will be freed by the automatically once the 1263 * device is freed. 1264 */ 1265 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id) 1266 { 1267 struct nvmem_device **ptr, *nvmem; 1268 1269 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL); 1270 if (!ptr) 1271 return ERR_PTR(-ENOMEM); 1272 1273 nvmem = nvmem_device_get(dev, id); 1274 if (!IS_ERR(nvmem)) { 1275 *ptr = nvmem; 1276 devres_add(dev, ptr); 1277 } else { 1278 devres_free(ptr); 1279 } 1280 1281 return nvmem; 1282 } 1283 EXPORT_SYMBOL_GPL(devm_nvmem_device_get); 1284 1285 static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, 1286 const char *id, int index) 1287 { 1288 struct nvmem_cell *cell; 1289 const char *name = NULL; 1290 1291 cell = kzalloc(sizeof(*cell), GFP_KERNEL); 1292 if (!cell) 1293 return ERR_PTR(-ENOMEM); 1294 1295 if (id) { 1296 name = kstrdup_const(id, GFP_KERNEL); 1297 if (!name) { 1298 kfree(cell); 1299 return ERR_PTR(-ENOMEM); 1300 } 1301 } 1302 1303 cell->id = name; 1304 cell->entry = entry; 1305 cell->index = index; 1306 1307 return cell; 1308 } 1309 1310 static struct nvmem_cell * 1311 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id) 1312 { 1313 struct nvmem_cell_entry *cell_entry; 1314 struct nvmem_cell *cell = ERR_PTR(-ENOENT); 1315 struct nvmem_cell_lookup *lookup; 1316 struct nvmem_device *nvmem; 1317 const char *dev_id; 1318 1319 if (!dev) 1320 return ERR_PTR(-EINVAL); 1321 1322 dev_id = dev_name(dev); 1323 1324 mutex_lock(&nvmem_lookup_mutex); 1325 1326 list_for_each_entry(lookup, &nvmem_lookup_list, node) { 1327 if ((strcmp(lookup->dev_id, dev_id) == 0) && 1328 (strcmp(lookup->con_id, con_id) == 0)) { 1329 /* This is the right entry. */ 1330 nvmem = __nvmem_device_get((void *)lookup->nvmem_name, 1331 device_match_name); 1332 if (IS_ERR(nvmem)) { 1333 /* Provider may not be registered yet. */ 1334 cell = ERR_CAST(nvmem); 1335 break; 1336 } 1337 1338 cell_entry = nvmem_find_cell_entry_by_name(nvmem, 1339 lookup->cell_name); 1340 if (!cell_entry) { 1341 __nvmem_device_put(nvmem); 1342 cell = ERR_PTR(-ENOENT); 1343 } else { 1344 cell = nvmem_create_cell(cell_entry, con_id, 0); 1345 if (IS_ERR(cell)) 1346 __nvmem_device_put(nvmem); 1347 } 1348 break; 1349 } 1350 } 1351 1352 mutex_unlock(&nvmem_lookup_mutex); 1353 return cell; 1354 } 1355 1356 static void nvmem_layout_module_put(struct nvmem_device *nvmem) 1357 { 1358 if (nvmem->layout && nvmem->layout->dev.driver) 1359 module_put(nvmem->layout->dev.driver->owner); 1360 } 1361 1362 #if IS_ENABLED(CONFIG_OF) 1363 static struct nvmem_cell_entry * 1364 nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np) 1365 { 1366 struct nvmem_cell_entry *iter, *cell = NULL; 1367 1368 mutex_lock(&nvmem_mutex); 1369 list_for_each_entry(iter, &nvmem->cells, node) { 1370 if (np == iter->np) { 1371 cell = iter; 1372 break; 1373 } 1374 } 1375 mutex_unlock(&nvmem_mutex); 1376 1377 return cell; 1378 } 1379 1380 static int nvmem_layout_module_get_optional(struct nvmem_device *nvmem) 1381 { 1382 if (!nvmem->layout) 1383 return 0; 1384 1385 if (!nvmem->layout->dev.driver || 1386 !try_module_get(nvmem->layout->dev.driver->owner)) 1387 return -EPROBE_DEFER; 1388 1389 return 0; 1390 } 1391 1392 /** 1393 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id 1394 * 1395 * @np: Device tree node that uses the nvmem cell. 1396 * @id: nvmem cell name from nvmem-cell-names property, or NULL 1397 * for the cell at index 0 (the lone cell with no accompanying 1398 * nvmem-cell-names property). 1399 * 1400 * Return: Will be an ERR_PTR() on error or a valid pointer 1401 * to a struct nvmem_cell. The nvmem_cell will be freed by the 1402 * nvmem_cell_put(). 1403 */ 1404 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id) 1405 { 1406 struct device_node *cell_np, *nvmem_np; 1407 struct nvmem_device *nvmem; 1408 struct nvmem_cell_entry *cell_entry; 1409 struct nvmem_cell *cell; 1410 struct of_phandle_args cell_spec; 1411 int index = 0; 1412 int cell_index = 0; 1413 int ret; 1414 1415 /* if cell name exists, find index to the name */ 1416 if (id) 1417 index = of_property_match_string(np, "nvmem-cell-names", id); 1418 1419 ret = of_parse_phandle_with_optional_args(np, "nvmem-cells", 1420 "#nvmem-cell-cells", 1421 index, &cell_spec); 1422 if (ret) 1423 return ERR_PTR(-ENOENT); 1424 1425 if (cell_spec.args_count > 1) 1426 return ERR_PTR(-EINVAL); 1427 1428 cell_np = cell_spec.np; 1429 if (cell_spec.args_count) 1430 cell_index = cell_spec.args[0]; 1431 1432 nvmem_np = of_get_parent(cell_np); 1433 if (!nvmem_np) { 1434 of_node_put(cell_np); 1435 return ERR_PTR(-EINVAL); 1436 } 1437 1438 /* nvmem layouts produce cells within the nvmem-layout container */ 1439 if (of_node_name_eq(nvmem_np, "nvmem-layout")) { 1440 nvmem_np = of_get_next_parent(nvmem_np); 1441 if (!nvmem_np) { 1442 of_node_put(cell_np); 1443 return ERR_PTR(-EINVAL); 1444 } 1445 } 1446 1447 nvmem = __nvmem_device_get(nvmem_np, device_match_of_node); 1448 of_node_put(nvmem_np); 1449 if (IS_ERR(nvmem)) { 1450 of_node_put(cell_np); 1451 return ERR_CAST(nvmem); 1452 } 1453 1454 ret = nvmem_layout_module_get_optional(nvmem); 1455 if (ret) { 1456 of_node_put(cell_np); 1457 __nvmem_device_put(nvmem); 1458 return ERR_PTR(ret); 1459 } 1460 1461 cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np); 1462 of_node_put(cell_np); 1463 if (!cell_entry) { 1464 __nvmem_device_put(nvmem); 1465 nvmem_layout_module_put(nvmem); 1466 if (nvmem->layout) 1467 return ERR_PTR(-EPROBE_DEFER); 1468 else 1469 return ERR_PTR(-ENOENT); 1470 } 1471 1472 cell = nvmem_create_cell(cell_entry, id, cell_index); 1473 if (IS_ERR(cell)) { 1474 __nvmem_device_put(nvmem); 1475 nvmem_layout_module_put(nvmem); 1476 } 1477 1478 return cell; 1479 } 1480 EXPORT_SYMBOL_GPL(of_nvmem_cell_get); 1481 #endif 1482 1483 /** 1484 * nvmem_cell_get() - Get nvmem cell of device form a given cell name 1485 * 1486 * @dev: Device that requests the nvmem cell. 1487 * @id: nvmem cell name to get (this corresponds with the name from the 1488 * nvmem-cell-names property for DT systems and with the con_id from 1489 * the lookup entry for non-DT systems). 1490 * 1491 * Return: Will be an ERR_PTR() on error or a valid pointer 1492 * to a struct nvmem_cell. The nvmem_cell will be freed by the 1493 * nvmem_cell_put(). 1494 */ 1495 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id) 1496 { 1497 struct nvmem_cell *cell; 1498 1499 if (dev->of_node) { /* try dt first */ 1500 cell = of_nvmem_cell_get(dev->of_node, id); 1501 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER) 1502 return cell; 1503 } 1504 1505 /* NULL cell id only allowed for device tree; invalid otherwise */ 1506 if (!id) 1507 return ERR_PTR(-EINVAL); 1508 1509 return nvmem_cell_get_from_lookup(dev, id); 1510 } 1511 EXPORT_SYMBOL_GPL(nvmem_cell_get); 1512 1513 static void devm_nvmem_cell_release(struct device *dev, void *res) 1514 { 1515 nvmem_cell_put(*(struct nvmem_cell **)res); 1516 } 1517 1518 /** 1519 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id 1520 * 1521 * @dev: Device that requests the nvmem cell. 1522 * @id: nvmem cell name id to get. 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 * automatically once the device is freed. 1527 */ 1528 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id) 1529 { 1530 struct nvmem_cell **ptr, *cell; 1531 1532 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL); 1533 if (!ptr) 1534 return ERR_PTR(-ENOMEM); 1535 1536 cell = nvmem_cell_get(dev, id); 1537 if (!IS_ERR(cell)) { 1538 *ptr = cell; 1539 devres_add(dev, ptr); 1540 } else { 1541 devres_free(ptr); 1542 } 1543 1544 return cell; 1545 } 1546 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get); 1547 1548 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data) 1549 { 1550 struct nvmem_cell **c = res; 1551 1552 if (WARN_ON(!c || !*c)) 1553 return 0; 1554 1555 return *c == data; 1556 } 1557 1558 /** 1559 * devm_nvmem_cell_put() - Release previously allocated nvmem cell 1560 * from devm_nvmem_cell_get. 1561 * 1562 * @dev: Device that requests the nvmem cell. 1563 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get(). 1564 */ 1565 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell) 1566 { 1567 int ret; 1568 1569 ret = devres_release(dev, devm_nvmem_cell_release, 1570 devm_nvmem_cell_match, cell); 1571 1572 WARN_ON(ret); 1573 } 1574 EXPORT_SYMBOL(devm_nvmem_cell_put); 1575 1576 /** 1577 * nvmem_cell_put() - Release previously allocated nvmem cell. 1578 * 1579 * @cell: Previously allocated nvmem cell by nvmem_cell_get(). 1580 */ 1581 void nvmem_cell_put(struct nvmem_cell *cell) 1582 { 1583 struct nvmem_device *nvmem = cell->entry->nvmem; 1584 1585 if (cell->id) 1586 kfree_const(cell->id); 1587 1588 kfree(cell); 1589 __nvmem_device_put(nvmem); 1590 nvmem_layout_module_put(nvmem); 1591 } 1592 EXPORT_SYMBOL_GPL(nvmem_cell_put); 1593 1594 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf) 1595 { 1596 u8 *p, *b; 1597 int i, extra, bit_offset = cell->bit_offset; 1598 1599 p = b = buf; 1600 if (bit_offset) { 1601 /* First shift */ 1602 *b++ >>= bit_offset; 1603 1604 /* setup rest of the bytes if any */ 1605 for (i = 1; i < cell->bytes; i++) { 1606 /* Get bits from next byte and shift them towards msb */ 1607 *p |= *b << (BITS_PER_BYTE - bit_offset); 1608 1609 p = b; 1610 *b++ >>= bit_offset; 1611 } 1612 } else { 1613 /* point to the msb */ 1614 p += cell->bytes - 1; 1615 } 1616 1617 /* result fits in less bytes */ 1618 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE); 1619 while (--extra >= 0) 1620 *p-- = 0; 1621 1622 /* clear msb bits if any leftover in the last byte */ 1623 if (cell->nbits % BITS_PER_BYTE) 1624 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0); 1625 } 1626 1627 static int __nvmem_cell_read(struct nvmem_device *nvmem, 1628 struct nvmem_cell_entry *cell, 1629 void *buf, size_t *len, const char *id, int index) 1630 { 1631 int rc; 1632 1633 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len); 1634 1635 if (rc) 1636 return rc; 1637 1638 /* shift bits in-place */ 1639 if (cell->bit_offset || cell->nbits) 1640 nvmem_shift_read_buffer_in_place(cell, buf); 1641 1642 if (cell->read_post_process) { 1643 rc = cell->read_post_process(cell->priv, id, index, 1644 cell->offset, buf, cell->raw_len); 1645 if (rc) 1646 return rc; 1647 } 1648 1649 if (len) 1650 *len = cell->bytes; 1651 1652 return 0; 1653 } 1654 1655 /** 1656 * nvmem_cell_read() - Read a given nvmem cell 1657 * 1658 * @cell: nvmem cell to be read. 1659 * @len: pointer to length of cell which will be populated on successful read; 1660 * can be NULL. 1661 * 1662 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The 1663 * buffer should be freed by the consumer with a kfree(). 1664 */ 1665 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len) 1666 { 1667 struct nvmem_cell_entry *entry = cell->entry; 1668 struct nvmem_device *nvmem = entry->nvmem; 1669 u8 *buf; 1670 int rc; 1671 1672 if (!nvmem) 1673 return ERR_PTR(-EINVAL); 1674 1675 buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL); 1676 if (!buf) 1677 return ERR_PTR(-ENOMEM); 1678 1679 rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index); 1680 if (rc) { 1681 kfree(buf); 1682 return ERR_PTR(rc); 1683 } 1684 1685 return buf; 1686 } 1687 EXPORT_SYMBOL_GPL(nvmem_cell_read); 1688 1689 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell, 1690 u8 *_buf, int len) 1691 { 1692 struct nvmem_device *nvmem = cell->nvmem; 1693 int i, rc, nbits, bit_offset = cell->bit_offset; 1694 u8 v, *p, *buf, *b, pbyte, pbits; 1695 1696 nbits = cell->nbits; 1697 buf = kzalloc(cell->bytes, GFP_KERNEL); 1698 if (!buf) 1699 return ERR_PTR(-ENOMEM); 1700 1701 memcpy(buf, _buf, len); 1702 p = b = buf; 1703 1704 if (bit_offset) { 1705 pbyte = *b; 1706 *b <<= bit_offset; 1707 1708 /* setup the first byte with lsb bits from nvmem */ 1709 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1); 1710 if (rc) 1711 goto err; 1712 *b++ |= GENMASK(bit_offset - 1, 0) & v; 1713 1714 /* setup rest of the byte if any */ 1715 for (i = 1; i < cell->bytes; i++) { 1716 /* Get last byte bits and shift them towards lsb */ 1717 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset); 1718 pbyte = *b; 1719 p = b; 1720 *b <<= bit_offset; 1721 *b++ |= pbits; 1722 } 1723 } 1724 1725 /* if it's not end on byte boundary */ 1726 if ((nbits + bit_offset) % BITS_PER_BYTE) { 1727 /* setup the last byte with msb bits from nvmem */ 1728 rc = nvmem_reg_read(nvmem, 1729 cell->offset + cell->bytes - 1, &v, 1); 1730 if (rc) 1731 goto err; 1732 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v; 1733 1734 } 1735 1736 return buf; 1737 err: 1738 kfree(buf); 1739 return ERR_PTR(rc); 1740 } 1741 1742 static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len) 1743 { 1744 struct nvmem_device *nvmem = cell->nvmem; 1745 int rc; 1746 1747 if (!nvmem || nvmem->read_only || 1748 (cell->bit_offset == 0 && len != cell->bytes)) 1749 return -EINVAL; 1750 1751 /* 1752 * Any cells which have a read_post_process hook are read-only because 1753 * we cannot reverse the operation and it might affect other cells, 1754 * too. 1755 */ 1756 if (cell->read_post_process) 1757 return -EINVAL; 1758 1759 if (cell->bit_offset || cell->nbits) { 1760 buf = nvmem_cell_prepare_write_buffer(cell, buf, len); 1761 if (IS_ERR(buf)) 1762 return PTR_ERR(buf); 1763 } 1764 1765 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes); 1766 1767 /* free the tmp buffer */ 1768 if (cell->bit_offset || cell->nbits) 1769 kfree(buf); 1770 1771 if (rc) 1772 return rc; 1773 1774 return len; 1775 } 1776 1777 /** 1778 * nvmem_cell_write() - Write to a given nvmem cell 1779 * 1780 * @cell: nvmem cell to be written. 1781 * @buf: Buffer to be written. 1782 * @len: length of buffer to be written to nvmem cell. 1783 * 1784 * Return: length of bytes written or negative on failure. 1785 */ 1786 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len) 1787 { 1788 return __nvmem_cell_entry_write(cell->entry, buf, len); 1789 } 1790 1791 EXPORT_SYMBOL_GPL(nvmem_cell_write); 1792 1793 static int nvmem_cell_read_common(struct device *dev, const char *cell_id, 1794 void *val, size_t count) 1795 { 1796 struct nvmem_cell *cell; 1797 void *buf; 1798 size_t len; 1799 1800 cell = nvmem_cell_get(dev, cell_id); 1801 if (IS_ERR(cell)) 1802 return PTR_ERR(cell); 1803 1804 buf = nvmem_cell_read(cell, &len); 1805 if (IS_ERR(buf)) { 1806 nvmem_cell_put(cell); 1807 return PTR_ERR(buf); 1808 } 1809 if (len != count) { 1810 kfree(buf); 1811 nvmem_cell_put(cell); 1812 return -EINVAL; 1813 } 1814 memcpy(val, buf, count); 1815 kfree(buf); 1816 nvmem_cell_put(cell); 1817 1818 return 0; 1819 } 1820 1821 /** 1822 * nvmem_cell_read_u8() - Read a cell value as a u8 1823 * 1824 * @dev: Device that requests the nvmem cell. 1825 * @cell_id: Name of nvmem cell to read. 1826 * @val: pointer to output value. 1827 * 1828 * Return: 0 on success or negative errno. 1829 */ 1830 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val) 1831 { 1832 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); 1833 } 1834 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8); 1835 1836 /** 1837 * nvmem_cell_read_u16() - Read a cell value as a u16 1838 * 1839 * @dev: Device that requests the nvmem cell. 1840 * @cell_id: Name of nvmem cell to read. 1841 * @val: pointer to output value. 1842 * 1843 * Return: 0 on success or negative errno. 1844 */ 1845 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val) 1846 { 1847 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); 1848 } 1849 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16); 1850 1851 /** 1852 * nvmem_cell_read_u32() - Read a cell value as a u32 1853 * 1854 * @dev: Device that requests the nvmem cell. 1855 * @cell_id: Name of nvmem cell to read. 1856 * @val: pointer to output value. 1857 * 1858 * Return: 0 on success or negative errno. 1859 */ 1860 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val) 1861 { 1862 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); 1863 } 1864 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32); 1865 1866 /** 1867 * nvmem_cell_read_u64() - Read a cell value as a u64 1868 * 1869 * @dev: Device that requests the nvmem cell. 1870 * @cell_id: Name of nvmem cell to read. 1871 * @val: pointer to output value. 1872 * 1873 * Return: 0 on success or negative errno. 1874 */ 1875 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val) 1876 { 1877 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); 1878 } 1879 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64); 1880 1881 static const void *nvmem_cell_read_variable_common(struct device *dev, 1882 const char *cell_id, 1883 size_t max_len, size_t *len) 1884 { 1885 struct nvmem_cell *cell; 1886 int nbits; 1887 void *buf; 1888 1889 cell = nvmem_cell_get(dev, cell_id); 1890 if (IS_ERR(cell)) 1891 return cell; 1892 1893 nbits = cell->entry->nbits; 1894 buf = nvmem_cell_read(cell, len); 1895 nvmem_cell_put(cell); 1896 if (IS_ERR(buf)) 1897 return buf; 1898 1899 /* 1900 * If nbits is set then nvmem_cell_read() can significantly exaggerate 1901 * the length of the real data. Throw away the extra junk. 1902 */ 1903 if (nbits) 1904 *len = DIV_ROUND_UP(nbits, 8); 1905 1906 if (*len > max_len) { 1907 kfree(buf); 1908 return ERR_PTR(-ERANGE); 1909 } 1910 1911 return buf; 1912 } 1913 1914 /** 1915 * nvmem_cell_read_variable_le_u32() - Read up to 32-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_u32(struct device *dev, const char *cell_id, 1924 u32 *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 |= buf[i] << (8 * i); 1938 1939 kfree(buf); 1940 1941 return 0; 1942 } 1943 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32); 1944 1945 /** 1946 * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number. 1947 * 1948 * @dev: Device that requests the nvmem cell. 1949 * @cell_id: Name of nvmem cell to read. 1950 * @val: pointer to output value. 1951 * 1952 * Return: 0 on success or negative errno. 1953 */ 1954 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id, 1955 u64 *val) 1956 { 1957 size_t len; 1958 const u8 *buf; 1959 int i; 1960 1961 buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len); 1962 if (IS_ERR(buf)) 1963 return PTR_ERR(buf); 1964 1965 /* Copy w/ implicit endian conversion */ 1966 *val = 0; 1967 for (i = 0; i < len; i++) 1968 *val |= (uint64_t)buf[i] << (8 * i); 1969 1970 kfree(buf); 1971 1972 return 0; 1973 } 1974 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64); 1975 1976 /** 1977 * nvmem_device_cell_read() - Read a given nvmem device and cell 1978 * 1979 * @nvmem: nvmem device to read from. 1980 * @info: nvmem cell info to be read. 1981 * @buf: buffer pointer which will be populated on successful read. 1982 * 1983 * Return: length of successful bytes read on success and negative 1984 * error code on error. 1985 */ 1986 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem, 1987 struct nvmem_cell_info *info, void *buf) 1988 { 1989 struct nvmem_cell_entry cell; 1990 int rc; 1991 ssize_t len; 1992 1993 if (!nvmem) 1994 return -EINVAL; 1995 1996 rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell); 1997 if (rc) 1998 return rc; 1999 2000 rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0); 2001 if (rc) 2002 return rc; 2003 2004 return len; 2005 } 2006 EXPORT_SYMBOL_GPL(nvmem_device_cell_read); 2007 2008 /** 2009 * nvmem_device_cell_write() - Write cell to a given nvmem device 2010 * 2011 * @nvmem: nvmem device to be written to. 2012 * @info: nvmem cell info to be written. 2013 * @buf: buffer to be written to cell. 2014 * 2015 * Return: length of bytes written or negative error code on failure. 2016 */ 2017 int nvmem_device_cell_write(struct nvmem_device *nvmem, 2018 struct nvmem_cell_info *info, void *buf) 2019 { 2020 struct nvmem_cell_entry cell; 2021 int rc; 2022 2023 if (!nvmem) 2024 return -EINVAL; 2025 2026 rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell); 2027 if (rc) 2028 return rc; 2029 2030 return __nvmem_cell_entry_write(&cell, buf, cell.bytes); 2031 } 2032 EXPORT_SYMBOL_GPL(nvmem_device_cell_write); 2033 2034 /** 2035 * nvmem_device_read() - Read from a given nvmem device 2036 * 2037 * @nvmem: nvmem device to read from. 2038 * @offset: offset in nvmem device. 2039 * @bytes: number of bytes to read. 2040 * @buf: buffer pointer which will be populated on successful read. 2041 * 2042 * Return: length of successful bytes read on success and negative 2043 * error code on error. 2044 */ 2045 int nvmem_device_read(struct nvmem_device *nvmem, 2046 unsigned int offset, 2047 size_t bytes, void *buf) 2048 { 2049 int rc; 2050 2051 if (!nvmem) 2052 return -EINVAL; 2053 2054 rc = nvmem_reg_read(nvmem, offset, buf, bytes); 2055 2056 if (rc) 2057 return rc; 2058 2059 return bytes; 2060 } 2061 EXPORT_SYMBOL_GPL(nvmem_device_read); 2062 2063 /** 2064 * nvmem_device_write() - Write cell to a given nvmem device 2065 * 2066 * @nvmem: nvmem device to be written to. 2067 * @offset: offset in nvmem device. 2068 * @bytes: number of bytes to write. 2069 * @buf: buffer to be written. 2070 * 2071 * Return: length of bytes written or negative error code on failure. 2072 */ 2073 int nvmem_device_write(struct nvmem_device *nvmem, 2074 unsigned int offset, 2075 size_t bytes, void *buf) 2076 { 2077 int rc; 2078 2079 if (!nvmem) 2080 return -EINVAL; 2081 2082 rc = nvmem_reg_write(nvmem, offset, buf, bytes); 2083 2084 if (rc) 2085 return rc; 2086 2087 2088 return bytes; 2089 } 2090 EXPORT_SYMBOL_GPL(nvmem_device_write); 2091 2092 /** 2093 * nvmem_add_cell_table() - register a table of cell info entries 2094 * 2095 * @table: table of cell info entries 2096 */ 2097 void nvmem_add_cell_table(struct nvmem_cell_table *table) 2098 { 2099 mutex_lock(&nvmem_cell_mutex); 2100 list_add_tail(&table->node, &nvmem_cell_tables); 2101 mutex_unlock(&nvmem_cell_mutex); 2102 } 2103 EXPORT_SYMBOL_GPL(nvmem_add_cell_table); 2104 2105 /** 2106 * nvmem_del_cell_table() - remove a previously registered cell info table 2107 * 2108 * @table: table of cell info entries 2109 */ 2110 void nvmem_del_cell_table(struct nvmem_cell_table *table) 2111 { 2112 mutex_lock(&nvmem_cell_mutex); 2113 list_del(&table->node); 2114 mutex_unlock(&nvmem_cell_mutex); 2115 } 2116 EXPORT_SYMBOL_GPL(nvmem_del_cell_table); 2117 2118 /** 2119 * nvmem_add_cell_lookups() - register a list of cell lookup entries 2120 * 2121 * @entries: array of cell lookup entries 2122 * @nentries: number of cell lookup entries in the array 2123 */ 2124 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) 2125 { 2126 int i; 2127 2128 mutex_lock(&nvmem_lookup_mutex); 2129 for (i = 0; i < nentries; i++) 2130 list_add_tail(&entries[i].node, &nvmem_lookup_list); 2131 mutex_unlock(&nvmem_lookup_mutex); 2132 } 2133 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups); 2134 2135 /** 2136 * nvmem_del_cell_lookups() - remove a list of previously added cell lookup 2137 * entries 2138 * 2139 * @entries: array of cell lookup entries 2140 * @nentries: number of cell lookup entries in the array 2141 */ 2142 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) 2143 { 2144 int i; 2145 2146 mutex_lock(&nvmem_lookup_mutex); 2147 for (i = 0; i < nentries; i++) 2148 list_del(&entries[i].node); 2149 mutex_unlock(&nvmem_lookup_mutex); 2150 } 2151 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups); 2152 2153 /** 2154 * nvmem_dev_name() - Get the name of a given nvmem device. 2155 * 2156 * @nvmem: nvmem device. 2157 * 2158 * Return: name of the nvmem device. 2159 */ 2160 const char *nvmem_dev_name(struct nvmem_device *nvmem) 2161 { 2162 return dev_name(&nvmem->dev); 2163 } 2164 EXPORT_SYMBOL_GPL(nvmem_dev_name); 2165 2166 /** 2167 * nvmem_dev_size() - Get the size of a given nvmem device. 2168 * 2169 * @nvmem: nvmem device. 2170 * 2171 * Return: size of the nvmem device. 2172 */ 2173 size_t nvmem_dev_size(struct nvmem_device *nvmem) 2174 { 2175 return nvmem->size; 2176 } 2177 EXPORT_SYMBOL_GPL(nvmem_dev_size); 2178 2179 static int __init nvmem_init(void) 2180 { 2181 int ret; 2182 2183 ret = bus_register(&nvmem_bus_type); 2184 if (ret) 2185 return ret; 2186 2187 ret = nvmem_layout_bus_register(); 2188 if (ret) 2189 bus_unregister(&nvmem_bus_type); 2190 2191 return ret; 2192 } 2193 2194 static void __exit nvmem_exit(void) 2195 { 2196 nvmem_layout_bus_unregister(); 2197 bus_unregister(&nvmem_bus_type); 2198 } 2199 2200 subsys_initcall(nvmem_init); 2201 module_exit(nvmem_exit); 2202 2203 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org"); 2204 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); 2205 MODULE_DESCRIPTION("nvmem Driver Core"); 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