1 // SPDX-License-Identifier: GPL-2.0
3 * nvmem framework core.
5 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
6 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
9 #include <linux/device.h>
10 #include <linux/export.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>
20 #include <linux/slab.h>
34 struct bin_attribute eeprom;
35 struct device *base_dev;
36 struct list_head cells;
37 const struct nvmem_keepout *keepout;
38 unsigned int nkeepout;
39 nvmem_reg_read_t reg_read;
40 nvmem_reg_write_t reg_write;
41 struct gpio_desc *wp_gpio;
45 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
47 #define FLAG_COMPAT BIT(0)
55 struct device_node *np;
56 struct nvmem_device *nvmem;
57 struct list_head node;
60 static DEFINE_MUTEX(nvmem_mutex);
61 static DEFINE_IDA(nvmem_ida);
63 static DEFINE_MUTEX(nvmem_cell_mutex);
64 static LIST_HEAD(nvmem_cell_tables);
66 static DEFINE_MUTEX(nvmem_lookup_mutex);
67 static LIST_HEAD(nvmem_lookup_list);
69 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
71 static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
72 void *val, size_t bytes)
75 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
80 static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
81 void *val, size_t bytes)
85 if (nvmem->reg_write) {
86 gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
87 ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
88 gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
95 static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
96 unsigned int offset, void *val,
97 size_t bytes, int write)
100 unsigned int end = offset + bytes;
101 unsigned int kend, ksize;
102 const struct nvmem_keepout *keepout = nvmem->keepout;
103 const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
107 * Skip all keepouts before the range being accessed.
108 * Keepouts are sorted.
110 while ((keepout < keepoutend) && (keepout->end <= offset))
113 while ((offset < end) && (keepout < keepoutend)) {
114 /* Access the valid portion before the keepout. */
115 if (offset < keepout->start) {
116 kend = min(end, keepout->start);
117 ksize = kend - offset;
119 rc = __nvmem_reg_write(nvmem, offset, val, ksize);
121 rc = __nvmem_reg_read(nvmem, offset, val, ksize);
131 * Now we're aligned to the start of this keepout zone. Go
134 kend = min(end, keepout->end);
135 ksize = kend - offset;
137 memset(val, keepout->value, ksize);
145 * If we ran out of keepouts but there's still stuff to do, send it
149 ksize = end - offset;
151 return __nvmem_reg_write(nvmem, offset, val, ksize);
153 return __nvmem_reg_read(nvmem, offset, val, ksize);
159 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
160 void *val, size_t bytes)
162 if (!nvmem->nkeepout)
163 return __nvmem_reg_read(nvmem, offset, val, bytes);
165 return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
168 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
169 void *val, size_t bytes)
171 if (!nvmem->nkeepout)
172 return __nvmem_reg_write(nvmem, offset, val, bytes);
174 return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true);
177 #ifdef CONFIG_NVMEM_SYSFS
178 static const char * const nvmem_type_str[] = {
179 [NVMEM_TYPE_UNKNOWN] = "Unknown",
180 [NVMEM_TYPE_EEPROM] = "EEPROM",
181 [NVMEM_TYPE_OTP] = "OTP",
182 [NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
183 [NVMEM_TYPE_FRAM] = "FRAM",
186 #ifdef CONFIG_DEBUG_LOCK_ALLOC
187 static struct lock_class_key eeprom_lock_key;
190 static ssize_t type_show(struct device *dev,
191 struct device_attribute *attr, char *buf)
193 struct nvmem_device *nvmem = to_nvmem_device(dev);
195 return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]);
198 static DEVICE_ATTR_RO(type);
200 static struct attribute *nvmem_attrs[] = {
205 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
206 struct bin_attribute *attr, char *buf,
207 loff_t pos, size_t count)
210 struct nvmem_device *nvmem;
216 dev = kobj_to_dev(kobj);
217 nvmem = to_nvmem_device(dev);
219 /* Stop the user from reading */
220 if (pos >= nvmem->size)
223 if (!IS_ALIGNED(pos, nvmem->stride))
226 if (count < nvmem->word_size)
229 if (pos + count > nvmem->size)
230 count = nvmem->size - pos;
232 count = round_down(count, nvmem->word_size);
234 if (!nvmem->reg_read)
237 rc = nvmem_reg_read(nvmem, pos, buf, count);
245 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
246 struct bin_attribute *attr, char *buf,
247 loff_t pos, size_t count)
250 struct nvmem_device *nvmem;
256 dev = kobj_to_dev(kobj);
257 nvmem = to_nvmem_device(dev);
259 /* Stop the user from writing */
260 if (pos >= nvmem->size)
263 if (!IS_ALIGNED(pos, nvmem->stride))
266 if (count < nvmem->word_size)
269 if (pos + count > nvmem->size)
270 count = nvmem->size - pos;
272 count = round_down(count, nvmem->word_size);
274 if (!nvmem->reg_write)
277 rc = nvmem_reg_write(nvmem, pos, buf, count);
285 static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
289 if (!nvmem->root_only)
292 if (!nvmem->read_only)
295 if (!nvmem->reg_write)
298 if (!nvmem->reg_read)
304 static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
305 struct bin_attribute *attr, int i)
307 struct device *dev = kobj_to_dev(kobj);
308 struct nvmem_device *nvmem = to_nvmem_device(dev);
310 attr->size = nvmem->size;
312 return nvmem_bin_attr_get_umode(nvmem);
315 /* default read/write permissions */
316 static struct bin_attribute bin_attr_rw_nvmem = {
321 .read = bin_attr_nvmem_read,
322 .write = bin_attr_nvmem_write,
325 static struct bin_attribute *nvmem_bin_attributes[] = {
330 static const struct attribute_group nvmem_bin_group = {
331 .bin_attrs = nvmem_bin_attributes,
332 .attrs = nvmem_attrs,
333 .is_bin_visible = nvmem_bin_attr_is_visible,
336 static const struct attribute_group *nvmem_dev_groups[] = {
341 static struct bin_attribute bin_attr_nvmem_eeprom_compat = {
345 .read = bin_attr_nvmem_read,
346 .write = bin_attr_nvmem_write,
350 * nvmem_setup_compat() - Create an additional binary entry in
351 * drivers sys directory, to be backwards compatible with the older
352 * drivers/misc/eeprom drivers.
354 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
355 const struct nvmem_config *config)
362 if (!config->base_dev)
365 if (config->type == NVMEM_TYPE_FRAM)
366 bin_attr_nvmem_eeprom_compat.attr.name = "fram";
368 nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
369 nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
370 nvmem->eeprom.size = nvmem->size;
371 #ifdef CONFIG_DEBUG_LOCK_ALLOC
372 nvmem->eeprom.attr.key = &eeprom_lock_key;
374 nvmem->eeprom.private = &nvmem->dev;
375 nvmem->base_dev = config->base_dev;
377 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
380 "Failed to create eeprom binary file %d\n", rval);
384 nvmem->flags |= FLAG_COMPAT;
389 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
390 const struct nvmem_config *config)
393 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
396 #else /* CONFIG_NVMEM_SYSFS */
398 static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
399 const struct nvmem_config *config)
403 static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
404 const struct nvmem_config *config)
408 #endif /* CONFIG_NVMEM_SYSFS */
410 static void nvmem_release(struct device *dev)
412 struct nvmem_device *nvmem = to_nvmem_device(dev);
414 ida_free(&nvmem_ida, nvmem->id);
415 gpiod_put(nvmem->wp_gpio);
419 static const struct device_type nvmem_provider_type = {
420 .release = nvmem_release,
423 static struct bus_type nvmem_bus_type = {
427 static void nvmem_cell_drop(struct nvmem_cell *cell)
429 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
430 mutex_lock(&nvmem_mutex);
431 list_del(&cell->node);
432 mutex_unlock(&nvmem_mutex);
433 of_node_put(cell->np);
434 kfree_const(cell->name);
438 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
440 struct nvmem_cell *cell, *p;
442 list_for_each_entry_safe(cell, p, &nvmem->cells, node)
443 nvmem_cell_drop(cell);
446 static void nvmem_cell_add(struct nvmem_cell *cell)
448 mutex_lock(&nvmem_mutex);
449 list_add_tail(&cell->node, &cell->nvmem->cells);
450 mutex_unlock(&nvmem_mutex);
451 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
454 static int nvmem_cell_info_to_nvmem_cell_nodup(struct nvmem_device *nvmem,
455 const struct nvmem_cell_info *info,
456 struct nvmem_cell *cell)
459 cell->offset = info->offset;
460 cell->bytes = info->bytes;
461 cell->name = info->name;
463 cell->bit_offset = info->bit_offset;
464 cell->nbits = info->nbits;
467 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
470 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
472 "cell %s unaligned to nvmem stride %d\n",
473 cell->name ?: "<unknown>", nvmem->stride);
480 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
481 const struct nvmem_cell_info *info,
482 struct nvmem_cell *cell)
486 err = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, cell);
490 cell->name = kstrdup_const(info->name, GFP_KERNEL);
498 * nvmem_add_cells() - Add cell information to an nvmem device
500 * @nvmem: nvmem device to add cells to.
501 * @info: nvmem cell info to add to the device
502 * @ncells: number of cells in info
504 * Return: 0 or negative error code on failure.
506 static int nvmem_add_cells(struct nvmem_device *nvmem,
507 const struct nvmem_cell_info *info,
510 struct nvmem_cell **cells;
513 cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
517 for (i = 0; i < ncells; i++) {
518 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
524 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
530 nvmem_cell_add(cells[i]);
533 /* remove tmp array */
539 nvmem_cell_drop(cells[i]);
547 * nvmem_register_notifier() - Register a notifier block for nvmem events.
549 * @nb: notifier block to be called on nvmem events.
551 * Return: 0 on success, negative error number on failure.
553 int nvmem_register_notifier(struct notifier_block *nb)
555 return blocking_notifier_chain_register(&nvmem_notifier, nb);
557 EXPORT_SYMBOL_GPL(nvmem_register_notifier);
560 * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
562 * @nb: notifier block to be unregistered.
564 * Return: 0 on success, negative error number on failure.
566 int nvmem_unregister_notifier(struct notifier_block *nb)
568 return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
570 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
572 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
574 const struct nvmem_cell_info *info;
575 struct nvmem_cell_table *table;
576 struct nvmem_cell *cell;
579 mutex_lock(&nvmem_cell_mutex);
580 list_for_each_entry(table, &nvmem_cell_tables, node) {
581 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
582 for (i = 0; i < table->ncells; i++) {
583 info = &table->cells[i];
585 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
591 rval = nvmem_cell_info_to_nvmem_cell(nvmem,
599 nvmem_cell_add(cell);
605 mutex_unlock(&nvmem_cell_mutex);
609 static struct nvmem_cell *
610 nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
612 struct nvmem_cell *iter, *cell = NULL;
614 mutex_lock(&nvmem_mutex);
615 list_for_each_entry(iter, &nvmem->cells, node) {
616 if (strcmp(cell_id, iter->name) == 0) {
621 mutex_unlock(&nvmem_mutex);
626 static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
628 unsigned int cur = 0;
629 const struct nvmem_keepout *keepout = nvmem->keepout;
630 const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
632 while (keepout < keepoutend) {
633 /* Ensure keepouts are sorted and don't overlap. */
634 if (keepout->start < cur) {
636 "Keepout regions aren't sorted or overlap.\n");
641 if (keepout->end < keepout->start) {
643 "Invalid keepout region.\n");
649 * Validate keepouts (and holes between) don't violate
650 * word_size constraints.
652 if ((keepout->end - keepout->start < nvmem->word_size) ||
653 ((keepout->start != cur) &&
654 (keepout->start - cur < nvmem->word_size))) {
657 "Keepout regions violate word_size constraints.\n");
662 /* Validate keepouts don't violate stride (alignment). */
663 if (!IS_ALIGNED(keepout->start, nvmem->stride) ||
664 !IS_ALIGNED(keepout->end, nvmem->stride)) {
667 "Keepout regions violate stride.\n");
679 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
681 struct device_node *parent, *child;
682 struct device *dev = &nvmem->dev;
683 struct nvmem_cell *cell;
687 parent = dev->of_node;
689 for_each_child_of_node(parent, child) {
690 addr = of_get_property(child, "reg", &len);
693 if (len < 2 * sizeof(u32)) {
694 dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
699 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
706 cell->offset = be32_to_cpup(addr++);
707 cell->bytes = be32_to_cpup(addr);
708 cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
710 addr = of_get_property(child, "bits", &len);
711 if (addr && len == (2 * sizeof(u32))) {
712 cell->bit_offset = be32_to_cpup(addr++);
713 cell->nbits = be32_to_cpup(addr);
717 cell->bytes = DIV_ROUND_UP(
718 cell->nbits + cell->bit_offset,
721 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
722 dev_err(dev, "cell %s unaligned to nvmem stride %d\n",
723 cell->name, nvmem->stride);
724 /* Cells already added will be freed later. */
725 kfree_const(cell->name);
731 cell->np = of_node_get(child);
732 nvmem_cell_add(cell);
739 * nvmem_register() - Register a nvmem device for given nvmem_config.
740 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
742 * @config: nvmem device configuration with which nvmem device is created.
744 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
748 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
750 struct nvmem_device *nvmem;
754 return ERR_PTR(-EINVAL);
756 if (!config->reg_read && !config->reg_write)
757 return ERR_PTR(-EINVAL);
759 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
761 return ERR_PTR(-ENOMEM);
763 rval = ida_alloc(&nvmem_ida, GFP_KERNEL);
766 return ERR_PTR(rval);
770 nvmem->wp_gpio = config->wp_gpio;
771 else if (!config->ignore_wp)
772 nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
774 if (IS_ERR(nvmem->wp_gpio)) {
775 ida_free(&nvmem_ida, nvmem->id);
776 rval = PTR_ERR(nvmem->wp_gpio);
778 return ERR_PTR(rval);
781 kref_init(&nvmem->refcnt);
782 INIT_LIST_HEAD(&nvmem->cells);
785 nvmem->owner = config->owner;
786 if (!nvmem->owner && config->dev->driver)
787 nvmem->owner = config->dev->driver->owner;
788 nvmem->stride = config->stride ?: 1;
789 nvmem->word_size = config->word_size ?: 1;
790 nvmem->size = config->size;
791 nvmem->dev.type = &nvmem_provider_type;
792 nvmem->dev.bus = &nvmem_bus_type;
793 nvmem->dev.parent = config->dev;
794 nvmem->root_only = config->root_only;
795 nvmem->priv = config->priv;
796 nvmem->type = config->type;
797 nvmem->reg_read = config->reg_read;
798 nvmem->reg_write = config->reg_write;
799 nvmem->keepout = config->keepout;
800 nvmem->nkeepout = config->nkeepout;
802 nvmem->dev.of_node = config->of_node;
803 else if (!config->no_of_node)
804 nvmem->dev.of_node = config->dev->of_node;
806 switch (config->id) {
807 case NVMEM_DEVID_NONE:
808 dev_set_name(&nvmem->dev, "%s", config->name);
810 case NVMEM_DEVID_AUTO:
811 dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
814 dev_set_name(&nvmem->dev, "%s%d",
815 config->name ? : "nvmem",
816 config->name ? config->id : nvmem->id);
820 nvmem->read_only = device_property_present(config->dev, "read-only") ||
821 config->read_only || !nvmem->reg_write;
823 #ifdef CONFIG_NVMEM_SYSFS
824 nvmem->dev.groups = nvmem_dev_groups;
827 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
829 rval = device_register(&nvmem->dev);
833 if (nvmem->nkeepout) {
834 rval = nvmem_validate_keepouts(nvmem);
839 if (config->compat) {
840 rval = nvmem_sysfs_setup_compat(nvmem, config);
846 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
848 goto err_teardown_compat;
851 rval = nvmem_add_cells_from_table(nvmem);
853 goto err_remove_cells;
855 rval = nvmem_add_cells_from_of(nvmem);
857 goto err_remove_cells;
859 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
864 nvmem_device_remove_all_cells(nvmem);
867 nvmem_sysfs_remove_compat(nvmem, config);
869 device_del(&nvmem->dev);
871 put_device(&nvmem->dev);
873 return ERR_PTR(rval);
875 EXPORT_SYMBOL_GPL(nvmem_register);
877 static void nvmem_device_release(struct kref *kref)
879 struct nvmem_device *nvmem;
881 nvmem = container_of(kref, struct nvmem_device, refcnt);
883 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
885 if (nvmem->flags & FLAG_COMPAT)
886 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
888 nvmem_device_remove_all_cells(nvmem);
889 device_unregister(&nvmem->dev);
893 * nvmem_unregister() - Unregister previously registered nvmem device
895 * @nvmem: Pointer to previously registered nvmem device.
897 void nvmem_unregister(struct nvmem_device *nvmem)
899 kref_put(&nvmem->refcnt, nvmem_device_release);
901 EXPORT_SYMBOL_GPL(nvmem_unregister);
903 static void devm_nvmem_release(struct device *dev, void *res)
905 nvmem_unregister(*(struct nvmem_device **)res);
909 * devm_nvmem_register() - Register a managed nvmem device for given
911 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
913 * @dev: Device that uses the nvmem device.
914 * @config: nvmem device configuration with which nvmem device is created.
916 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
919 struct nvmem_device *devm_nvmem_register(struct device *dev,
920 const struct nvmem_config *config)
922 struct nvmem_device **ptr, *nvmem;
924 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
926 return ERR_PTR(-ENOMEM);
928 nvmem = nvmem_register(config);
930 if (!IS_ERR(nvmem)) {
932 devres_add(dev, ptr);
939 EXPORT_SYMBOL_GPL(devm_nvmem_register);
941 static int devm_nvmem_match(struct device *dev, void *res, void *data)
943 struct nvmem_device **r = res;
949 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
952 * @dev: Device that uses the nvmem device.
953 * @nvmem: Pointer to previously registered nvmem device.
955 * Return: Will be negative on error or zero on success.
957 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
959 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
961 EXPORT_SYMBOL(devm_nvmem_unregister);
963 static struct nvmem_device *__nvmem_device_get(void *data,
964 int (*match)(struct device *dev, const void *data))
966 struct nvmem_device *nvmem = NULL;
969 mutex_lock(&nvmem_mutex);
970 dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
972 nvmem = to_nvmem_device(dev);
973 mutex_unlock(&nvmem_mutex);
975 return ERR_PTR(-EPROBE_DEFER);
977 if (!try_module_get(nvmem->owner)) {
979 "could not increase module refcount for cell %s\n",
980 nvmem_dev_name(nvmem));
982 put_device(&nvmem->dev);
983 return ERR_PTR(-EINVAL);
986 kref_get(&nvmem->refcnt);
991 static void __nvmem_device_put(struct nvmem_device *nvmem)
993 put_device(&nvmem->dev);
994 module_put(nvmem->owner);
995 kref_put(&nvmem->refcnt, nvmem_device_release);
998 #if IS_ENABLED(CONFIG_OF)
1000 * of_nvmem_device_get() - Get nvmem device from a given id
1002 * @np: Device tree node that uses the nvmem device.
1003 * @id: nvmem name from nvmem-names property.
1005 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1008 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
1011 struct device_node *nvmem_np;
1012 struct nvmem_device *nvmem;
1016 index = of_property_match_string(np, "nvmem-names", id);
1018 nvmem_np = of_parse_phandle(np, "nvmem", index);
1020 return ERR_PTR(-ENOENT);
1022 nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1023 of_node_put(nvmem_np);
1026 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
1030 * nvmem_device_get() - Get nvmem device from a given id
1032 * @dev: Device that uses the nvmem device.
1033 * @dev_name: name of the requested nvmem device.
1035 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1038 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
1040 if (dev->of_node) { /* try dt first */
1041 struct nvmem_device *nvmem;
1043 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
1045 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
1050 return __nvmem_device_get((void *)dev_name, device_match_name);
1052 EXPORT_SYMBOL_GPL(nvmem_device_get);
1055 * nvmem_device_find() - Find nvmem device with matching function
1057 * @data: Data to pass to match function
1058 * @match: Callback function to check device
1060 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
1063 struct nvmem_device *nvmem_device_find(void *data,
1064 int (*match)(struct device *dev, const void *data))
1066 return __nvmem_device_get(data, match);
1068 EXPORT_SYMBOL_GPL(nvmem_device_find);
1070 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
1072 struct nvmem_device **nvmem = res;
1074 if (WARN_ON(!nvmem || !*nvmem))
1077 return *nvmem == data;
1080 static void devm_nvmem_device_release(struct device *dev, void *res)
1082 nvmem_device_put(*(struct nvmem_device **)res);
1086 * devm_nvmem_device_put() - put alredy got nvmem device
1088 * @dev: Device that uses the nvmem device.
1089 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
1090 * that needs to be released.
1092 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
1096 ret = devres_release(dev, devm_nvmem_device_release,
1097 devm_nvmem_device_match, nvmem);
1101 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
1104 * nvmem_device_put() - put alredy got nvmem device
1106 * @nvmem: pointer to nvmem device that needs to be released.
1108 void nvmem_device_put(struct nvmem_device *nvmem)
1110 __nvmem_device_put(nvmem);
1112 EXPORT_SYMBOL_GPL(nvmem_device_put);
1115 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
1117 * @dev: Device that requests the nvmem device.
1118 * @id: name id for the requested nvmem device.
1120 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
1121 * on success. The nvmem_cell will be freed by the automatically once the
1124 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
1126 struct nvmem_device **ptr, *nvmem;
1128 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
1130 return ERR_PTR(-ENOMEM);
1132 nvmem = nvmem_device_get(dev, id);
1133 if (!IS_ERR(nvmem)) {
1135 devres_add(dev, ptr);
1142 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
1144 static struct nvmem_cell *
1145 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
1147 struct nvmem_cell *cell = ERR_PTR(-ENOENT);
1148 struct nvmem_cell_lookup *lookup;
1149 struct nvmem_device *nvmem;
1153 return ERR_PTR(-EINVAL);
1155 dev_id = dev_name(dev);
1157 mutex_lock(&nvmem_lookup_mutex);
1159 list_for_each_entry(lookup, &nvmem_lookup_list, node) {
1160 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
1161 (strcmp(lookup->con_id, con_id) == 0)) {
1162 /* This is the right entry. */
1163 nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
1165 if (IS_ERR(nvmem)) {
1166 /* Provider may not be registered yet. */
1167 cell = ERR_CAST(nvmem);
1171 cell = nvmem_find_cell_by_name(nvmem,
1174 __nvmem_device_put(nvmem);
1175 cell = ERR_PTR(-ENOENT);
1181 mutex_unlock(&nvmem_lookup_mutex);
1185 #if IS_ENABLED(CONFIG_OF)
1186 static struct nvmem_cell *
1187 nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
1189 struct nvmem_cell *iter, *cell = NULL;
1191 mutex_lock(&nvmem_mutex);
1192 list_for_each_entry(iter, &nvmem->cells, node) {
1193 if (np == iter->np) {
1198 mutex_unlock(&nvmem_mutex);
1204 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
1206 * @np: Device tree node that uses the nvmem cell.
1207 * @id: nvmem cell name from nvmem-cell-names property, or NULL
1208 * for the cell at index 0 (the lone cell with no accompanying
1209 * nvmem-cell-names property).
1211 * Return: Will be an ERR_PTR() on error or a valid pointer
1212 * to a struct nvmem_cell. The nvmem_cell will be freed by the
1215 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
1217 struct device_node *cell_np, *nvmem_np;
1218 struct nvmem_device *nvmem;
1219 struct nvmem_cell *cell;
1222 /* if cell name exists, find index to the name */
1224 index = of_property_match_string(np, "nvmem-cell-names", id);
1226 cell_np = of_parse_phandle(np, "nvmem-cells", index);
1228 return ERR_PTR(-ENOENT);
1230 nvmem_np = of_get_next_parent(cell_np);
1232 return ERR_PTR(-EINVAL);
1234 nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
1235 of_node_put(nvmem_np);
1237 return ERR_CAST(nvmem);
1239 cell = nvmem_find_cell_by_node(nvmem, cell_np);
1241 __nvmem_device_put(nvmem);
1242 return ERR_PTR(-ENOENT);
1247 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
1251 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
1253 * @dev: Device that requests the nvmem cell.
1254 * @id: nvmem cell name to get (this corresponds with the name from the
1255 * nvmem-cell-names property for DT systems and with the con_id from
1256 * the lookup entry for non-DT systems).
1258 * Return: Will be an ERR_PTR() on error or a valid pointer
1259 * to a struct nvmem_cell. The nvmem_cell will be freed by the
1262 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
1264 struct nvmem_cell *cell;
1266 if (dev->of_node) { /* try dt first */
1267 cell = of_nvmem_cell_get(dev->of_node, id);
1268 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
1272 /* NULL cell id only allowed for device tree; invalid otherwise */
1274 return ERR_PTR(-EINVAL);
1276 return nvmem_cell_get_from_lookup(dev, id);
1278 EXPORT_SYMBOL_GPL(nvmem_cell_get);
1280 static void devm_nvmem_cell_release(struct device *dev, void *res)
1282 nvmem_cell_put(*(struct nvmem_cell **)res);
1286 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
1288 * @dev: Device that requests the nvmem cell.
1289 * @id: nvmem cell name id to get.
1291 * Return: Will be an ERR_PTR() on error or a valid pointer
1292 * to a struct nvmem_cell. The nvmem_cell will be freed by the
1293 * automatically once the device is freed.
1295 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
1297 struct nvmem_cell **ptr, *cell;
1299 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
1301 return ERR_PTR(-ENOMEM);
1303 cell = nvmem_cell_get(dev, id);
1304 if (!IS_ERR(cell)) {
1306 devres_add(dev, ptr);
1313 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
1315 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
1317 struct nvmem_cell **c = res;
1319 if (WARN_ON(!c || !*c))
1326 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1327 * from devm_nvmem_cell_get.
1329 * @dev: Device that requests the nvmem cell.
1330 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1332 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1336 ret = devres_release(dev, devm_nvmem_cell_release,
1337 devm_nvmem_cell_match, cell);
1341 EXPORT_SYMBOL(devm_nvmem_cell_put);
1344 * nvmem_cell_put() - Release previously allocated nvmem cell.
1346 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1348 void nvmem_cell_put(struct nvmem_cell *cell)
1350 struct nvmem_device *nvmem = cell->nvmem;
1352 __nvmem_device_put(nvmem);
1354 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1356 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
1359 int i, extra, bit_offset = cell->bit_offset;
1364 *b++ >>= bit_offset;
1366 /* setup rest of the bytes if any */
1367 for (i = 1; i < cell->bytes; i++) {
1368 /* Get bits from next byte and shift them towards msb */
1369 *p |= *b << (BITS_PER_BYTE - bit_offset);
1372 *b++ >>= bit_offset;
1375 /* point to the msb */
1376 p += cell->bytes - 1;
1379 /* result fits in less bytes */
1380 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1381 while (--extra >= 0)
1384 /* clear msb bits if any leftover in the last byte */
1385 if (cell->nbits % BITS_PER_BYTE)
1386 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1389 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1390 struct nvmem_cell *cell,
1391 void *buf, size_t *len)
1395 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1400 /* shift bits in-place */
1401 if (cell->bit_offset || cell->nbits)
1402 nvmem_shift_read_buffer_in_place(cell, buf);
1411 * nvmem_cell_read() - Read a given nvmem cell
1413 * @cell: nvmem cell to be read.
1414 * @len: pointer to length of cell which will be populated on successful read;
1417 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1418 * buffer should be freed by the consumer with a kfree().
1420 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1422 struct nvmem_device *nvmem = cell->nvmem;
1427 return ERR_PTR(-EINVAL);
1429 buf = kzalloc(cell->bytes, GFP_KERNEL);
1431 return ERR_PTR(-ENOMEM);
1433 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1441 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1443 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1446 struct nvmem_device *nvmem = cell->nvmem;
1447 int i, rc, nbits, bit_offset = cell->bit_offset;
1448 u8 v, *p, *buf, *b, pbyte, pbits;
1450 nbits = cell->nbits;
1451 buf = kzalloc(cell->bytes, GFP_KERNEL);
1453 return ERR_PTR(-ENOMEM);
1455 memcpy(buf, _buf, len);
1462 /* setup the first byte with lsb bits from nvmem */
1463 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1466 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1468 /* setup rest of the byte if any */
1469 for (i = 1; i < cell->bytes; i++) {
1470 /* Get last byte bits and shift them towards lsb */
1471 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1479 /* if it's not end on byte boundary */
1480 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1481 /* setup the last byte with msb bits from nvmem */
1482 rc = nvmem_reg_read(nvmem,
1483 cell->offset + cell->bytes - 1, &v, 1);
1486 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1497 * nvmem_cell_write() - Write to a given nvmem cell
1499 * @cell: nvmem cell to be written.
1500 * @buf: Buffer to be written.
1501 * @len: length of buffer to be written to nvmem cell.
1503 * Return: length of bytes written or negative on failure.
1505 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1507 struct nvmem_device *nvmem = cell->nvmem;
1510 if (!nvmem || nvmem->read_only ||
1511 (cell->bit_offset == 0 && len != cell->bytes))
1514 if (cell->bit_offset || cell->nbits) {
1515 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1517 return PTR_ERR(buf);
1520 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1522 /* free the tmp buffer */
1523 if (cell->bit_offset || cell->nbits)
1531 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1533 static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
1534 void *val, size_t count)
1536 struct nvmem_cell *cell;
1540 cell = nvmem_cell_get(dev, cell_id);
1542 return PTR_ERR(cell);
1544 buf = nvmem_cell_read(cell, &len);
1546 nvmem_cell_put(cell);
1547 return PTR_ERR(buf);
1551 nvmem_cell_put(cell);
1554 memcpy(val, buf, count);
1556 nvmem_cell_put(cell);
1562 * nvmem_cell_read_u8() - Read a cell value as a u8
1564 * @dev: Device that requests the nvmem cell.
1565 * @cell_id: Name of nvmem cell to read.
1566 * @val: pointer to output value.
1568 * Return: 0 on success or negative errno.
1570 int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
1572 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1574 EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);
1577 * nvmem_cell_read_u16() - Read a cell value as a u16
1579 * @dev: Device that requests the nvmem cell.
1580 * @cell_id: Name of nvmem cell to read.
1581 * @val: pointer to output value.
1583 * Return: 0 on success or negative errno.
1585 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1587 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1589 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1592 * nvmem_cell_read_u32() - Read a cell value as a u32
1594 * @dev: Device that requests the nvmem cell.
1595 * @cell_id: Name of nvmem cell to read.
1596 * @val: pointer to output value.
1598 * Return: 0 on success or negative errno.
1600 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1602 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1604 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1607 * nvmem_cell_read_u64() - Read a cell value as a u64
1609 * @dev: Device that requests the nvmem cell.
1610 * @cell_id: Name of nvmem cell to read.
1611 * @val: pointer to output value.
1613 * Return: 0 on success or negative errno.
1615 int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
1617 return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
1619 EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);
1621 static const void *nvmem_cell_read_variable_common(struct device *dev,
1622 const char *cell_id,
1623 size_t max_len, size_t *len)
1625 struct nvmem_cell *cell;
1629 cell = nvmem_cell_get(dev, cell_id);
1633 nbits = cell->nbits;
1634 buf = nvmem_cell_read(cell, len);
1635 nvmem_cell_put(cell);
1640 * If nbits is set then nvmem_cell_read() can significantly exaggerate
1641 * the length of the real data. Throw away the extra junk.
1644 *len = DIV_ROUND_UP(nbits, 8);
1646 if (*len > max_len) {
1648 return ERR_PTR(-ERANGE);
1655 * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
1657 * @dev: Device that requests the nvmem cell.
1658 * @cell_id: Name of nvmem cell to read.
1659 * @val: pointer to output value.
1661 * Return: 0 on success or negative errno.
1663 int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
1670 buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1672 return PTR_ERR(buf);
1674 /* Copy w/ implicit endian conversion */
1676 for (i = 0; i < len; i++)
1677 *val |= buf[i] << (8 * i);
1683 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);
1686 * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
1688 * @dev: Device that requests the nvmem cell.
1689 * @cell_id: Name of nvmem cell to read.
1690 * @val: pointer to output value.
1692 * Return: 0 on success or negative errno.
1694 int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
1701 buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
1703 return PTR_ERR(buf);
1705 /* Copy w/ implicit endian conversion */
1707 for (i = 0; i < len; i++)
1708 *val |= (uint64_t)buf[i] << (8 * i);
1714 EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);
1717 * nvmem_device_cell_read() - Read a given nvmem device and cell
1719 * @nvmem: nvmem device to read from.
1720 * @info: nvmem cell info to be read.
1721 * @buf: buffer pointer which will be populated on successful read.
1723 * Return: length of successful bytes read on success and negative
1724 * error code on error.
1726 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1727 struct nvmem_cell_info *info, void *buf)
1729 struct nvmem_cell cell;
1736 rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
1740 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1746 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1749 * nvmem_device_cell_write() - Write cell to a given nvmem device
1751 * @nvmem: nvmem device to be written to.
1752 * @info: nvmem cell info to be written.
1753 * @buf: buffer to be written to cell.
1755 * Return: length of bytes written or negative error code on failure.
1757 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1758 struct nvmem_cell_info *info, void *buf)
1760 struct nvmem_cell cell;
1766 rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
1770 return nvmem_cell_write(&cell, buf, cell.bytes);
1772 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1775 * nvmem_device_read() - Read from a given nvmem device
1777 * @nvmem: nvmem device to read from.
1778 * @offset: offset in nvmem device.
1779 * @bytes: number of bytes to read.
1780 * @buf: buffer pointer which will be populated on successful read.
1782 * Return: length of successful bytes read on success and negative
1783 * error code on error.
1785 int nvmem_device_read(struct nvmem_device *nvmem,
1786 unsigned int offset,
1787 size_t bytes, void *buf)
1794 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1801 EXPORT_SYMBOL_GPL(nvmem_device_read);
1804 * nvmem_device_write() - Write cell to a given nvmem device
1806 * @nvmem: nvmem device to be written to.
1807 * @offset: offset in nvmem device.
1808 * @bytes: number of bytes to write.
1809 * @buf: buffer to be written.
1811 * Return: length of bytes written or negative error code on failure.
1813 int nvmem_device_write(struct nvmem_device *nvmem,
1814 unsigned int offset,
1815 size_t bytes, void *buf)
1822 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1830 EXPORT_SYMBOL_GPL(nvmem_device_write);
1833 * nvmem_add_cell_table() - register a table of cell info entries
1835 * @table: table of cell info entries
1837 void nvmem_add_cell_table(struct nvmem_cell_table *table)
1839 mutex_lock(&nvmem_cell_mutex);
1840 list_add_tail(&table->node, &nvmem_cell_tables);
1841 mutex_unlock(&nvmem_cell_mutex);
1843 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
1846 * nvmem_del_cell_table() - remove a previously registered cell info table
1848 * @table: table of cell info entries
1850 void nvmem_del_cell_table(struct nvmem_cell_table *table)
1852 mutex_lock(&nvmem_cell_mutex);
1853 list_del(&table->node);
1854 mutex_unlock(&nvmem_cell_mutex);
1856 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
1859 * nvmem_add_cell_lookups() - register a list of cell lookup entries
1861 * @entries: array of cell lookup entries
1862 * @nentries: number of cell lookup entries in the array
1864 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1868 mutex_lock(&nvmem_lookup_mutex);
1869 for (i = 0; i < nentries; i++)
1870 list_add_tail(&entries[i].node, &nvmem_lookup_list);
1871 mutex_unlock(&nvmem_lookup_mutex);
1873 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
1876 * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
1879 * @entries: array of cell lookup entries
1880 * @nentries: number of cell lookup entries in the array
1882 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1886 mutex_lock(&nvmem_lookup_mutex);
1887 for (i = 0; i < nentries; i++)
1888 list_del(&entries[i].node);
1889 mutex_unlock(&nvmem_lookup_mutex);
1891 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
1894 * nvmem_dev_name() - Get the name of a given nvmem device.
1896 * @nvmem: nvmem device.
1898 * Return: name of the nvmem device.
1900 const char *nvmem_dev_name(struct nvmem_device *nvmem)
1902 return dev_name(&nvmem->dev);
1904 EXPORT_SYMBOL_GPL(nvmem_dev_name);
1906 static int __init nvmem_init(void)
1908 return bus_register(&nvmem_bus_type);
1911 static void __exit nvmem_exit(void)
1913 bus_unregister(&nvmem_bus_type);
1916 subsys_initcall(nvmem_init);
1917 module_exit(nvmem_exit);
1919 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1920 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1921 MODULE_DESCRIPTION("nvmem Driver Core");
1922 MODULE_LICENSE("GPL v2");