2 * nvmem framework core.
4 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
5 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 and
9 * only version 2 as published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 #include <linux/device.h>
18 #include <linux/export.h>
20 #include <linux/idr.h>
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/nvmem-consumer.h>
24 #include <linux/nvmem-provider.h>
26 #include <linux/regmap.h>
27 #include <linux/slab.h>
31 struct regmap *regmap;
49 struct nvmem_device *nvmem;
50 struct list_head node;
53 static DEFINE_MUTEX(nvmem_mutex);
54 static DEFINE_IDA(nvmem_ida);
56 static LIST_HEAD(nvmem_cells);
57 static DEFINE_MUTEX(nvmem_cells_mutex);
59 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
61 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
62 struct bin_attribute *attr,
63 char *buf, loff_t pos, size_t count)
65 struct device *dev = container_of(kobj, struct device, kobj);
66 struct nvmem_device *nvmem = to_nvmem_device(dev);
69 /* Stop the user from reading */
70 if (pos >= nvmem->size)
73 if (pos + count > nvmem->size)
74 count = nvmem->size - pos;
76 count = round_down(count, nvmem->word_size);
78 rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
86 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
87 struct bin_attribute *attr,
88 char *buf, loff_t pos, size_t count)
90 struct device *dev = container_of(kobj, struct device, kobj);
91 struct nvmem_device *nvmem = to_nvmem_device(dev);
94 /* Stop the user from writing */
95 if (pos >= nvmem->size)
98 if (pos + count > nvmem->size)
99 count = nvmem->size - pos;
101 count = round_down(count, nvmem->word_size);
103 rc = regmap_raw_write(nvmem->regmap, pos, buf, count);
105 if (IS_ERR_VALUE(rc))
111 /* default read/write permissions */
112 static struct bin_attribute bin_attr_rw_nvmem = {
115 .mode = S_IWUSR | S_IRUGO,
117 .read = bin_attr_nvmem_read,
118 .write = bin_attr_nvmem_write,
121 static struct bin_attribute *nvmem_bin_rw_attributes[] = {
126 static const struct attribute_group nvmem_bin_rw_group = {
127 .bin_attrs = nvmem_bin_rw_attributes,
130 static const struct attribute_group *nvmem_rw_dev_groups[] = {
135 /* read only permission */
136 static struct bin_attribute bin_attr_ro_nvmem = {
141 .read = bin_attr_nvmem_read,
144 static struct bin_attribute *nvmem_bin_ro_attributes[] = {
149 static const struct attribute_group nvmem_bin_ro_group = {
150 .bin_attrs = nvmem_bin_ro_attributes,
153 static const struct attribute_group *nvmem_ro_dev_groups[] = {
158 static void nvmem_release(struct device *dev)
160 struct nvmem_device *nvmem = to_nvmem_device(dev);
162 ida_simple_remove(&nvmem_ida, nvmem->id);
166 static const struct device_type nvmem_provider_type = {
167 .release = nvmem_release,
170 static struct bus_type nvmem_bus_type = {
174 static int of_nvmem_match(struct device *dev, void *nvmem_np)
176 return dev->of_node == nvmem_np;
179 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
186 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
191 return to_nvmem_device(d);
194 static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
196 struct nvmem_cell *p;
198 list_for_each_entry(p, &nvmem_cells, node)
199 if (p && !strcmp(p->name, cell_id))
205 static void nvmem_cell_drop(struct nvmem_cell *cell)
207 mutex_lock(&nvmem_cells_mutex);
208 list_del(&cell->node);
209 mutex_unlock(&nvmem_cells_mutex);
213 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
215 struct nvmem_cell *cell;
216 struct list_head *p, *n;
218 list_for_each_safe(p, n, &nvmem_cells) {
219 cell = list_entry(p, struct nvmem_cell, node);
220 if (cell->nvmem == nvmem)
221 nvmem_cell_drop(cell);
225 static void nvmem_cell_add(struct nvmem_cell *cell)
227 mutex_lock(&nvmem_cells_mutex);
228 list_add_tail(&cell->node, &nvmem_cells);
229 mutex_unlock(&nvmem_cells_mutex);
232 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
233 const struct nvmem_cell_info *info,
234 struct nvmem_cell *cell)
237 cell->offset = info->offset;
238 cell->bytes = info->bytes;
239 cell->name = info->name;
241 cell->bit_offset = info->bit_offset;
242 cell->nbits = info->nbits;
245 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
248 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
250 "cell %s unaligned to nvmem stride %d\n",
251 cell->name, nvmem->stride);
258 static int nvmem_add_cells(struct nvmem_device *nvmem,
259 const struct nvmem_config *cfg)
261 struct nvmem_cell **cells;
262 const struct nvmem_cell_info *info = cfg->cells;
265 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
269 for (i = 0; i < cfg->ncells; i++) {
270 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
276 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
277 if (IS_ERR_VALUE(rval)) {
282 nvmem_cell_add(cells[i]);
285 nvmem->ncells = cfg->ncells;
286 /* remove tmp array */
292 nvmem_cell_drop(cells[i]);
298 * nvmem_register() - Register a nvmem device for given nvmem_config.
299 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
301 * @config: nvmem device configuration with which nvmem device is created.
303 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
307 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
309 struct nvmem_device *nvmem;
310 struct device_node *np;
315 return ERR_PTR(-EINVAL);
317 rm = dev_get_regmap(config->dev, NULL);
319 dev_err(config->dev, "Regmap not found\n");
320 return ERR_PTR(-EINVAL);
323 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
325 return ERR_PTR(-ENOMEM);
327 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
330 return ERR_PTR(rval);
335 nvmem->owner = config->owner;
336 nvmem->stride = regmap_get_reg_stride(rm);
337 nvmem->word_size = regmap_get_val_bytes(rm);
338 nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
339 nvmem->dev.type = &nvmem_provider_type;
340 nvmem->dev.bus = &nvmem_bus_type;
341 nvmem->dev.parent = config->dev;
342 np = config->dev->of_node;
343 nvmem->dev.of_node = np;
344 dev_set_name(&nvmem->dev, "%s%d",
345 config->name ? : "nvmem", config->id);
347 nvmem->read_only = of_property_read_bool(np, "read-only") |
350 nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups :
353 device_initialize(&nvmem->dev);
355 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
357 rval = device_add(&nvmem->dev);
359 ida_simple_remove(&nvmem_ida, nvmem->id);
361 return ERR_PTR(rval);
365 nvmem_add_cells(nvmem, config);
369 EXPORT_SYMBOL_GPL(nvmem_register);
372 * nvmem_unregister() - Unregister previously registered nvmem device
374 * @nvmem: Pointer to previously registered nvmem device.
376 * Return: Will be an negative on error or a zero on success.
378 int nvmem_unregister(struct nvmem_device *nvmem)
380 mutex_lock(&nvmem_mutex);
382 mutex_unlock(&nvmem_mutex);
385 mutex_unlock(&nvmem_mutex);
387 nvmem_device_remove_all_cells(nvmem);
388 device_del(&nvmem->dev);
392 EXPORT_SYMBOL_GPL(nvmem_unregister);
394 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
395 struct nvmem_cell **cellp,
398 struct nvmem_device *nvmem = NULL;
400 mutex_lock(&nvmem_mutex);
403 nvmem = of_nvmem_find(np);
405 mutex_unlock(&nvmem_mutex);
406 return ERR_PTR(-EPROBE_DEFER);
409 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
417 mutex_unlock(&nvmem_mutex);
418 return ERR_PTR(-ENOENT);
423 mutex_unlock(&nvmem_mutex);
425 if (!try_module_get(nvmem->owner)) {
427 "could not increase module refcount for cell %s\n",
430 mutex_lock(&nvmem_mutex);
432 mutex_unlock(&nvmem_mutex);
434 return ERR_PTR(-EINVAL);
440 static void __nvmem_device_put(struct nvmem_device *nvmem)
442 module_put(nvmem->owner);
443 mutex_lock(&nvmem_mutex);
445 mutex_unlock(&nvmem_mutex);
448 static int nvmem_match(struct device *dev, void *data)
450 return !strcmp(dev_name(dev), data);
453 static struct nvmem_device *nvmem_find(const char *name)
457 d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
462 return to_nvmem_device(d);
465 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
467 * of_nvmem_device_get() - Get nvmem device from a given id
469 * @dev node: Device tree node that uses the nvmem device
470 * @id: nvmem name from nvmem-names property.
472 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
475 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
478 struct device_node *nvmem_np;
481 index = of_property_match_string(np, "nvmem-names", id);
483 nvmem_np = of_parse_phandle(np, "nvmem", index);
485 return ERR_PTR(-EINVAL);
487 return __nvmem_device_get(nvmem_np, NULL, NULL);
489 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
493 * nvmem_device_get() - Get nvmem device from a given id
495 * @dev : Device that uses the nvmem device
496 * @id: nvmem name from nvmem-names property.
498 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
501 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
503 if (dev->of_node) { /* try dt first */
504 struct nvmem_device *nvmem;
506 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
508 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
513 return nvmem_find(dev_name);
515 EXPORT_SYMBOL_GPL(nvmem_device_get);
517 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
519 struct nvmem_device **nvmem = res;
521 if (WARN_ON(!nvmem || !*nvmem))
524 return *nvmem == data;
527 static void devm_nvmem_device_release(struct device *dev, void *res)
529 nvmem_device_put(*(struct nvmem_device **)res);
533 * devm_nvmem_device_put() - put alredy got nvmem device
535 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
536 * that needs to be released.
538 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
542 ret = devres_release(dev, devm_nvmem_device_release,
543 devm_nvmem_device_match, nvmem);
547 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
550 * nvmem_device_put() - put alredy got nvmem device
552 * @nvmem: pointer to nvmem device that needs to be released.
554 void nvmem_device_put(struct nvmem_device *nvmem)
556 __nvmem_device_put(nvmem);
558 EXPORT_SYMBOL_GPL(nvmem_device_put);
561 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
563 * @dev node: Device tree node that uses the nvmem cell
564 * @id: nvmem name in nvmems property.
566 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
567 * on success. The nvmem_cell will be freed by the automatically once the
570 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
572 struct nvmem_device **ptr, *nvmem;
574 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
576 return ERR_PTR(-ENOMEM);
578 nvmem = nvmem_device_get(dev, id);
579 if (!IS_ERR(nvmem)) {
581 devres_add(dev, ptr);
588 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
590 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
592 struct nvmem_cell *cell = NULL;
593 struct nvmem_device *nvmem;
595 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
597 return ERR_CAST(nvmem);
602 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
604 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
606 * @dev node: Device tree node that uses the nvmem cell
607 * @id: nvmem cell name from nvmem-cell-names property.
609 * Return: Will be an ERR_PTR() on error or a valid pointer
610 * to a struct nvmem_cell. The nvmem_cell will be freed by the
613 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
616 struct device_node *cell_np, *nvmem_np;
617 struct nvmem_cell *cell;
618 struct nvmem_device *nvmem;
620 int rval, len, index;
622 index = of_property_match_string(np, "nvmem-cell-names", name);
624 cell_np = of_parse_phandle(np, "nvmem-cells", index);
626 return ERR_PTR(-EINVAL);
628 nvmem_np = of_get_next_parent(cell_np);
630 return ERR_PTR(-EINVAL);
632 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
634 return ERR_CAST(nvmem);
636 addr = of_get_property(cell_np, "reg", &len);
637 if (!addr || (len < 2 * sizeof(u32))) {
638 dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
644 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
651 cell->offset = be32_to_cpup(addr++);
652 cell->bytes = be32_to_cpup(addr);
653 cell->name = cell_np->name;
655 addr = of_get_property(cell_np, "bits", &len);
656 if (addr && len == (2 * sizeof(u32))) {
657 cell->bit_offset = be32_to_cpup(addr++);
658 cell->nbits = be32_to_cpup(addr);
662 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
665 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
667 "cell %s unaligned to nvmem stride %d\n",
668 cell->name, nvmem->stride);
673 nvmem_cell_add(cell);
681 __nvmem_device_put(nvmem);
683 return ERR_PTR(rval);
685 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
689 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
691 * @dev node: Device tree node that uses the nvmem cell
692 * @id: nvmem cell name to get.
694 * Return: Will be an ERR_PTR() on error or a valid pointer
695 * to a struct nvmem_cell. The nvmem_cell will be freed by the
698 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
700 struct nvmem_cell *cell;
702 if (dev->of_node) { /* try dt first */
703 cell = of_nvmem_cell_get(dev->of_node, cell_id);
704 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
708 return nvmem_cell_get_from_list(cell_id);
710 EXPORT_SYMBOL_GPL(nvmem_cell_get);
712 static void devm_nvmem_cell_release(struct device *dev, void *res)
714 nvmem_cell_put(*(struct nvmem_cell **)res);
718 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
720 * @dev node: Device tree node that uses the nvmem cell
721 * @id: nvmem id in nvmem-names property.
723 * Return: Will be an ERR_PTR() on error or a valid pointer
724 * to a struct nvmem_cell. The nvmem_cell will be freed by the
725 * automatically once the device is freed.
727 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
729 struct nvmem_cell **ptr, *cell;
731 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
733 return ERR_PTR(-ENOMEM);
735 cell = nvmem_cell_get(dev, id);
738 devres_add(dev, ptr);
745 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
747 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
749 struct nvmem_cell **c = res;
751 if (WARN_ON(!c || !*c))
758 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
759 * from devm_nvmem_cell_get.
761 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
763 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
767 ret = devres_release(dev, devm_nvmem_cell_release,
768 devm_nvmem_cell_match, cell);
772 EXPORT_SYMBOL(devm_nvmem_cell_put);
775 * nvmem_cell_put() - Release previously allocated nvmem cell.
777 * @cell: Previously allocated nvmem cell by nvmem_cell_get()
779 void nvmem_cell_put(struct nvmem_cell *cell)
781 struct nvmem_device *nvmem = cell->nvmem;
783 __nvmem_device_put(nvmem);
784 nvmem_cell_drop(cell);
786 EXPORT_SYMBOL_GPL(nvmem_cell_put);
788 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
792 int i, bit_offset = cell->bit_offset;
799 /* setup rest of the bytes if any */
800 for (i = 1; i < cell->bytes; i++) {
801 /* Get bits from next byte and shift them towards msb */
802 *p |= *b << (BITS_PER_BYTE - bit_offset);
808 /* result fits in less bytes */
809 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
812 /* clear msb bits if any leftover in the last byte */
813 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
816 static int __nvmem_cell_read(struct nvmem_device *nvmem,
817 struct nvmem_cell *cell,
818 void *buf, size_t *len)
822 rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
824 if (IS_ERR_VALUE(rc))
827 /* shift bits in-place */
828 if (cell->bit_offset || cell->nbits)
829 nvmem_shift_read_buffer_in_place(cell, buf);
837 * nvmem_cell_read() - Read a given nvmem cell
839 * @cell: nvmem cell to be read.
840 * @len: pointer to length of cell which will be populated on successful read.
842 * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
843 * The buffer should be freed by the consumer with a kfree().
845 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
847 struct nvmem_device *nvmem = cell->nvmem;
851 if (!nvmem || !nvmem->regmap)
852 return ERR_PTR(-EINVAL);
854 buf = kzalloc(cell->bytes, GFP_KERNEL);
856 return ERR_PTR(-ENOMEM);
858 rc = __nvmem_cell_read(nvmem, cell, buf, len);
859 if (IS_ERR_VALUE(rc)) {
866 EXPORT_SYMBOL_GPL(nvmem_cell_read);
868 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
871 struct nvmem_device *nvmem = cell->nvmem;
872 int i, rc, nbits, bit_offset = cell->bit_offset;
873 u8 v, *p, *buf, *b, pbyte, pbits;
876 buf = kzalloc(cell->bytes, GFP_KERNEL);
878 return ERR_PTR(-ENOMEM);
880 memcpy(buf, _buf, len);
887 /* setup the first byte with lsb bits from nvmem */
888 rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
889 *b++ |= GENMASK(bit_offset - 1, 0) & v;
891 /* setup rest of the byte if any */
892 for (i = 1; i < cell->bytes; i++) {
893 /* Get last byte bits and shift them towards lsb */
894 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
902 /* if it's not end on byte boundary */
903 if ((nbits + bit_offset) % BITS_PER_BYTE) {
904 /* setup the last byte with msb bits from nvmem */
905 rc = regmap_raw_read(nvmem->regmap,
906 cell->offset + cell->bytes - 1, &v, 1);
907 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
915 * nvmem_cell_write() - Write to a given nvmem cell
917 * @cell: nvmem cell to be written.
918 * @buf: Buffer to be written.
919 * @len: length of buffer to be written to nvmem cell.
921 * Return: length of bytes written or negative on failure.
923 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
925 struct nvmem_device *nvmem = cell->nvmem;
928 if (!nvmem || !nvmem->regmap || nvmem->read_only ||
929 (cell->bit_offset == 0 && len != cell->bytes))
932 if (cell->bit_offset || cell->nbits) {
933 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
938 rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);
940 /* free the tmp buffer */
941 if (cell->bit_offset || cell->nbits)
944 if (IS_ERR_VALUE(rc))
949 EXPORT_SYMBOL_GPL(nvmem_cell_write);
952 * nvmem_device_cell_read() - Read a given nvmem device and cell
954 * @nvmem: nvmem device to read from.
955 * @info: nvmem cell info to be read.
956 * @buf: buffer pointer which will be populated on successful read.
958 * Return: length of successful bytes read on success and negative
959 * error code on error.
961 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
962 struct nvmem_cell_info *info, void *buf)
964 struct nvmem_cell cell;
968 if (!nvmem || !nvmem->regmap)
971 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
972 if (IS_ERR_VALUE(rc))
975 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
976 if (IS_ERR_VALUE(rc))
981 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
984 * nvmem_device_cell_write() - Write cell to a given nvmem device
986 * @nvmem: nvmem device to be written to.
987 * @info: nvmem cell info to be written
988 * @buf: buffer to be written to cell.
990 * Return: length of bytes written or negative error code on failure.
992 int nvmem_device_cell_write(struct nvmem_device *nvmem,
993 struct nvmem_cell_info *info, void *buf)
995 struct nvmem_cell cell;
998 if (!nvmem || !nvmem->regmap)
1001 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1002 if (IS_ERR_VALUE(rc))
1005 return nvmem_cell_write(&cell, buf, cell.bytes);
1007 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1010 * nvmem_device_read() - Read from a given nvmem device
1012 * @nvmem: nvmem device to read from.
1013 * @offset: offset in nvmem device.
1014 * @bytes: number of bytes to read.
1015 * @buf: buffer pointer which will be populated on successful read.
1017 * Return: length of successful bytes read on success and negative
1018 * error code on error.
1020 int nvmem_device_read(struct nvmem_device *nvmem,
1021 unsigned int offset,
1022 size_t bytes, void *buf)
1026 if (!nvmem || !nvmem->regmap)
1029 rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);
1031 if (IS_ERR_VALUE(rc))
1036 EXPORT_SYMBOL_GPL(nvmem_device_read);
1039 * nvmem_device_write() - Write cell to a given nvmem device
1041 * @nvmem: nvmem device to be written to.
1042 * @offset: offset in nvmem device.
1043 * @bytes: number of bytes to write.
1044 * @buf: buffer to be written.
1046 * Return: length of bytes written or negative error code on failure.
1048 int nvmem_device_write(struct nvmem_device *nvmem,
1049 unsigned int offset,
1050 size_t bytes, void *buf)
1054 if (!nvmem || !nvmem->regmap)
1057 rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);
1059 if (IS_ERR_VALUE(rc))
1065 EXPORT_SYMBOL_GPL(nvmem_device_write);
1067 static int __init nvmem_init(void)
1069 return bus_register(&nvmem_bus_type);
1072 static void __exit nvmem_exit(void)
1074 bus_unregister(&nvmem_bus_type);
1077 subsys_initcall(nvmem_init);
1078 module_exit(nvmem_exit);
1080 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1081 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1082 MODULE_DESCRIPTION("nvmem Driver Core");
1083 MODULE_LICENSE("GPL v2");