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