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;
42 struct bin_attribute eeprom;
43 struct device *base_dev;
46 #define FLAG_COMPAT BIT(0)
54 struct nvmem_device *nvmem;
55 struct list_head node;
58 static DEFINE_MUTEX(nvmem_mutex);
59 static DEFINE_IDA(nvmem_ida);
61 static LIST_HEAD(nvmem_cells);
62 static DEFINE_MUTEX(nvmem_cells_mutex);
64 #ifdef CONFIG_DEBUG_LOCK_ALLOC
65 static struct lock_class_key eeprom_lock_key;
68 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
70 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
71 struct bin_attribute *attr,
72 char *buf, loff_t pos, size_t count)
75 struct nvmem_device *nvmem;
81 dev = container_of(kobj, struct device, kobj);
82 nvmem = to_nvmem_device(dev);
84 /* Stop the user from reading */
85 if (pos >= nvmem->size)
88 if (count < nvmem->word_size)
91 if (pos + count > nvmem->size)
92 count = nvmem->size - pos;
94 count = round_down(count, nvmem->word_size);
96 rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
104 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
105 struct bin_attribute *attr,
106 char *buf, loff_t pos, size_t count)
109 struct nvmem_device *nvmem;
115 dev = container_of(kobj, struct device, kobj);
116 nvmem = to_nvmem_device(dev);
118 /* Stop the user from writing */
119 if (pos >= nvmem->size)
122 if (count < nvmem->word_size)
125 if (pos + count > nvmem->size)
126 count = nvmem->size - pos;
128 count = round_down(count, nvmem->word_size);
130 rc = regmap_raw_write(nvmem->regmap, pos, buf, count);
132 if (IS_ERR_VALUE(rc))
138 /* default read/write permissions */
139 static struct bin_attribute bin_attr_rw_nvmem = {
142 .mode = S_IWUSR | S_IRUGO,
144 .read = bin_attr_nvmem_read,
145 .write = bin_attr_nvmem_write,
148 static struct bin_attribute *nvmem_bin_rw_attributes[] = {
153 static const struct attribute_group nvmem_bin_rw_group = {
154 .bin_attrs = nvmem_bin_rw_attributes,
157 static const struct attribute_group *nvmem_rw_dev_groups[] = {
162 /* read only permission */
163 static struct bin_attribute bin_attr_ro_nvmem = {
168 .read = bin_attr_nvmem_read,
171 static struct bin_attribute *nvmem_bin_ro_attributes[] = {
176 static const struct attribute_group nvmem_bin_ro_group = {
177 .bin_attrs = nvmem_bin_ro_attributes,
180 static const struct attribute_group *nvmem_ro_dev_groups[] = {
185 /* default read/write permissions, root only */
186 static struct bin_attribute bin_attr_rw_root_nvmem = {
189 .mode = S_IWUSR | S_IRUSR,
191 .read = bin_attr_nvmem_read,
192 .write = bin_attr_nvmem_write,
195 static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
196 &bin_attr_rw_root_nvmem,
200 static const struct attribute_group nvmem_bin_rw_root_group = {
201 .bin_attrs = nvmem_bin_rw_root_attributes,
204 static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
205 &nvmem_bin_rw_root_group,
209 /* read only permission, root only */
210 static struct bin_attribute bin_attr_ro_root_nvmem = {
215 .read = bin_attr_nvmem_read,
218 static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
219 &bin_attr_ro_root_nvmem,
223 static const struct attribute_group nvmem_bin_ro_root_group = {
224 .bin_attrs = nvmem_bin_ro_root_attributes,
227 static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
228 &nvmem_bin_ro_root_group,
232 static void nvmem_release(struct device *dev)
234 struct nvmem_device *nvmem = to_nvmem_device(dev);
236 ida_simple_remove(&nvmem_ida, nvmem->id);
240 static const struct device_type nvmem_provider_type = {
241 .release = nvmem_release,
244 static struct bus_type nvmem_bus_type = {
248 static int of_nvmem_match(struct device *dev, void *nvmem_np)
250 return dev->of_node == nvmem_np;
253 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
260 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
265 return to_nvmem_device(d);
268 static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
270 struct nvmem_cell *p;
272 list_for_each_entry(p, &nvmem_cells, node)
273 if (p && !strcmp(p->name, cell_id))
279 static void nvmem_cell_drop(struct nvmem_cell *cell)
281 mutex_lock(&nvmem_cells_mutex);
282 list_del(&cell->node);
283 mutex_unlock(&nvmem_cells_mutex);
287 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
289 struct nvmem_cell *cell;
290 struct list_head *p, *n;
292 list_for_each_safe(p, n, &nvmem_cells) {
293 cell = list_entry(p, struct nvmem_cell, node);
294 if (cell->nvmem == nvmem)
295 nvmem_cell_drop(cell);
299 static void nvmem_cell_add(struct nvmem_cell *cell)
301 mutex_lock(&nvmem_cells_mutex);
302 list_add_tail(&cell->node, &nvmem_cells);
303 mutex_unlock(&nvmem_cells_mutex);
306 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
307 const struct nvmem_cell_info *info,
308 struct nvmem_cell *cell)
311 cell->offset = info->offset;
312 cell->bytes = info->bytes;
313 cell->name = info->name;
315 cell->bit_offset = info->bit_offset;
316 cell->nbits = info->nbits;
319 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
322 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
324 "cell %s unaligned to nvmem stride %d\n",
325 cell->name, nvmem->stride);
332 static int nvmem_add_cells(struct nvmem_device *nvmem,
333 const struct nvmem_config *cfg)
335 struct nvmem_cell **cells;
336 const struct nvmem_cell_info *info = cfg->cells;
339 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
343 for (i = 0; i < cfg->ncells; i++) {
344 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
350 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
351 if (IS_ERR_VALUE(rval)) {
356 nvmem_cell_add(cells[i]);
359 nvmem->ncells = cfg->ncells;
360 /* remove tmp array */
366 nvmem_cell_drop(cells[i]);
374 * nvmem_setup_compat() - Create an additional binary entry in
375 * drivers sys directory, to be backwards compatible with the older
376 * drivers/misc/eeprom drivers.
378 static int nvmem_setup_compat(struct nvmem_device *nvmem,
379 const struct nvmem_config *config)
383 if (!config->base_dev)
386 if (nvmem->read_only)
387 nvmem->eeprom = bin_attr_ro_root_nvmem;
389 nvmem->eeprom = bin_attr_rw_root_nvmem;
390 nvmem->eeprom.attr.name = "eeprom";
391 nvmem->eeprom.size = nvmem->size;
392 #ifdef CONFIG_DEBUG_LOCK_ALLOC
393 nvmem->eeprom.attr.key = &eeprom_lock_key;
395 nvmem->eeprom.private = &nvmem->dev;
396 nvmem->base_dev = config->base_dev;
398 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
401 "Failed to create eeprom binary file %d\n", rval);
405 nvmem->flags |= FLAG_COMPAT;
411 * nvmem_register() - Register a nvmem device for given nvmem_config.
412 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
414 * @config: nvmem device configuration with which nvmem device is created.
416 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
420 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
422 struct nvmem_device *nvmem;
423 struct device_node *np;
428 return ERR_PTR(-EINVAL);
430 rm = dev_get_regmap(config->dev, NULL);
432 dev_err(config->dev, "Regmap not found\n");
433 return ERR_PTR(-EINVAL);
436 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
438 return ERR_PTR(-ENOMEM);
440 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
443 return ERR_PTR(rval);
448 nvmem->owner = config->owner;
449 nvmem->stride = regmap_get_reg_stride(rm);
450 nvmem->word_size = regmap_get_val_bytes(rm);
451 nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
452 nvmem->dev.type = &nvmem_provider_type;
453 nvmem->dev.bus = &nvmem_bus_type;
454 nvmem->dev.parent = config->dev;
455 np = config->dev->of_node;
456 nvmem->dev.of_node = np;
457 dev_set_name(&nvmem->dev, "%s%d",
458 config->name ? : "nvmem", config->id);
460 nvmem->read_only = of_property_read_bool(np, "read-only") |
463 if (config->root_only)
464 nvmem->dev.groups = nvmem->read_only ?
465 nvmem_ro_root_dev_groups :
466 nvmem_rw_root_dev_groups;
468 nvmem->dev.groups = nvmem->read_only ?
469 nvmem_ro_dev_groups :
472 device_initialize(&nvmem->dev);
474 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
476 rval = device_add(&nvmem->dev);
480 if (config->compat) {
481 rval = nvmem_setup_compat(nvmem, config);
487 nvmem_add_cells(nvmem, config);
491 ida_simple_remove(&nvmem_ida, nvmem->id);
493 return ERR_PTR(rval);
495 EXPORT_SYMBOL_GPL(nvmem_register);
498 * nvmem_unregister() - Unregister previously registered nvmem device
500 * @nvmem: Pointer to previously registered nvmem device.
502 * Return: Will be an negative on error or a zero on success.
504 int nvmem_unregister(struct nvmem_device *nvmem)
506 mutex_lock(&nvmem_mutex);
508 mutex_unlock(&nvmem_mutex);
511 mutex_unlock(&nvmem_mutex);
513 if (nvmem->flags & FLAG_COMPAT)
514 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
516 nvmem_device_remove_all_cells(nvmem);
517 device_del(&nvmem->dev);
521 EXPORT_SYMBOL_GPL(nvmem_unregister);
523 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
524 struct nvmem_cell **cellp,
527 struct nvmem_device *nvmem = NULL;
529 mutex_lock(&nvmem_mutex);
532 nvmem = of_nvmem_find(np);
534 mutex_unlock(&nvmem_mutex);
535 return ERR_PTR(-EPROBE_DEFER);
538 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
546 mutex_unlock(&nvmem_mutex);
547 return ERR_PTR(-ENOENT);
552 mutex_unlock(&nvmem_mutex);
554 if (!try_module_get(nvmem->owner)) {
556 "could not increase module refcount for cell %s\n",
559 mutex_lock(&nvmem_mutex);
561 mutex_unlock(&nvmem_mutex);
563 return ERR_PTR(-EINVAL);
569 static void __nvmem_device_put(struct nvmem_device *nvmem)
571 module_put(nvmem->owner);
572 mutex_lock(&nvmem_mutex);
574 mutex_unlock(&nvmem_mutex);
577 static int nvmem_match(struct device *dev, void *data)
579 return !strcmp(dev_name(dev), data);
582 static struct nvmem_device *nvmem_find(const char *name)
586 d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
591 return to_nvmem_device(d);
594 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
596 * of_nvmem_device_get() - Get nvmem device from a given id
598 * @dev node: Device tree node that uses the nvmem device
599 * @id: nvmem name from nvmem-names property.
601 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
604 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
607 struct device_node *nvmem_np;
610 index = of_property_match_string(np, "nvmem-names", id);
612 nvmem_np = of_parse_phandle(np, "nvmem", index);
614 return ERR_PTR(-EINVAL);
616 return __nvmem_device_get(nvmem_np, NULL, NULL);
618 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
622 * nvmem_device_get() - Get nvmem device from a given id
624 * @dev : Device that uses the nvmem device
625 * @id: nvmem name from nvmem-names property.
627 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
630 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
632 if (dev->of_node) { /* try dt first */
633 struct nvmem_device *nvmem;
635 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
637 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
642 return nvmem_find(dev_name);
644 EXPORT_SYMBOL_GPL(nvmem_device_get);
646 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
648 struct nvmem_device **nvmem = res;
650 if (WARN_ON(!nvmem || !*nvmem))
653 return *nvmem == data;
656 static void devm_nvmem_device_release(struct device *dev, void *res)
658 nvmem_device_put(*(struct nvmem_device **)res);
662 * devm_nvmem_device_put() - put alredy got nvmem device
664 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
665 * that needs to be released.
667 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
671 ret = devres_release(dev, devm_nvmem_device_release,
672 devm_nvmem_device_match, nvmem);
676 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
679 * nvmem_device_put() - put alredy got nvmem device
681 * @nvmem: pointer to nvmem device that needs to be released.
683 void nvmem_device_put(struct nvmem_device *nvmem)
685 __nvmem_device_put(nvmem);
687 EXPORT_SYMBOL_GPL(nvmem_device_put);
690 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
692 * @dev node: Device tree node that uses the nvmem cell
693 * @id: nvmem name in nvmems property.
695 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
696 * on success. The nvmem_cell will be freed by the automatically once the
699 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
701 struct nvmem_device **ptr, *nvmem;
703 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
705 return ERR_PTR(-ENOMEM);
707 nvmem = nvmem_device_get(dev, id);
708 if (!IS_ERR(nvmem)) {
710 devres_add(dev, ptr);
717 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
719 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
721 struct nvmem_cell *cell = NULL;
722 struct nvmem_device *nvmem;
724 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
726 return ERR_CAST(nvmem);
731 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
733 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
735 * @dev node: Device tree node that uses the nvmem cell
736 * @id: nvmem cell name from nvmem-cell-names property.
738 * Return: Will be an ERR_PTR() on error or a valid pointer
739 * to a struct nvmem_cell. The nvmem_cell will be freed by the
742 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
745 struct device_node *cell_np, *nvmem_np;
746 struct nvmem_cell *cell;
747 struct nvmem_device *nvmem;
749 int rval, len, index;
751 index = of_property_match_string(np, "nvmem-cell-names", name);
753 cell_np = of_parse_phandle(np, "nvmem-cells", index);
755 return ERR_PTR(-EINVAL);
757 nvmem_np = of_get_next_parent(cell_np);
759 return ERR_PTR(-EINVAL);
761 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
763 return ERR_CAST(nvmem);
765 addr = of_get_property(cell_np, "reg", &len);
766 if (!addr || (len < 2 * sizeof(u32))) {
767 dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
773 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
780 cell->offset = be32_to_cpup(addr++);
781 cell->bytes = be32_to_cpup(addr);
782 cell->name = cell_np->name;
784 addr = of_get_property(cell_np, "bits", &len);
785 if (addr && len == (2 * sizeof(u32))) {
786 cell->bit_offset = be32_to_cpup(addr++);
787 cell->nbits = be32_to_cpup(addr);
791 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
794 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
796 "cell %s unaligned to nvmem stride %d\n",
797 cell->name, nvmem->stride);
802 nvmem_cell_add(cell);
810 __nvmem_device_put(nvmem);
812 return ERR_PTR(rval);
814 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
818 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
820 * @dev node: Device tree node that uses the nvmem cell
821 * @id: nvmem cell name to get.
823 * Return: Will be an ERR_PTR() on error or a valid pointer
824 * to a struct nvmem_cell. The nvmem_cell will be freed by the
827 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
829 struct nvmem_cell *cell;
831 if (dev->of_node) { /* try dt first */
832 cell = of_nvmem_cell_get(dev->of_node, cell_id);
833 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
837 return nvmem_cell_get_from_list(cell_id);
839 EXPORT_SYMBOL_GPL(nvmem_cell_get);
841 static void devm_nvmem_cell_release(struct device *dev, void *res)
843 nvmem_cell_put(*(struct nvmem_cell **)res);
847 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
849 * @dev node: Device tree node that uses the nvmem cell
850 * @id: nvmem id in nvmem-names property.
852 * Return: Will be an ERR_PTR() on error or a valid pointer
853 * to a struct nvmem_cell. The nvmem_cell will be freed by the
854 * automatically once the device is freed.
856 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
858 struct nvmem_cell **ptr, *cell;
860 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
862 return ERR_PTR(-ENOMEM);
864 cell = nvmem_cell_get(dev, id);
867 devres_add(dev, ptr);
874 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
876 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
878 struct nvmem_cell **c = res;
880 if (WARN_ON(!c || !*c))
887 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
888 * from devm_nvmem_cell_get.
890 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
892 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
896 ret = devres_release(dev, devm_nvmem_cell_release,
897 devm_nvmem_cell_match, cell);
901 EXPORT_SYMBOL(devm_nvmem_cell_put);
904 * nvmem_cell_put() - Release previously allocated nvmem cell.
906 * @cell: Previously allocated nvmem cell by nvmem_cell_get()
908 void nvmem_cell_put(struct nvmem_cell *cell)
910 struct nvmem_device *nvmem = cell->nvmem;
912 __nvmem_device_put(nvmem);
913 nvmem_cell_drop(cell);
915 EXPORT_SYMBOL_GPL(nvmem_cell_put);
917 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
921 int i, bit_offset = cell->bit_offset;
928 /* setup rest of the bytes if any */
929 for (i = 1; i < cell->bytes; i++) {
930 /* Get bits from next byte and shift them towards msb */
931 *p |= *b << (BITS_PER_BYTE - bit_offset);
937 /* result fits in less bytes */
938 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
941 /* clear msb bits if any leftover in the last byte */
942 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
945 static int __nvmem_cell_read(struct nvmem_device *nvmem,
946 struct nvmem_cell *cell,
947 void *buf, size_t *len)
951 rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
953 if (IS_ERR_VALUE(rc))
956 /* shift bits in-place */
957 if (cell->bit_offset || cell->nbits)
958 nvmem_shift_read_buffer_in_place(cell, buf);
966 * nvmem_cell_read() - Read a given nvmem cell
968 * @cell: nvmem cell to be read.
969 * @len: pointer to length of cell which will be populated on successful read.
971 * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
972 * The buffer should be freed by the consumer with a kfree().
974 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
976 struct nvmem_device *nvmem = cell->nvmem;
980 if (!nvmem || !nvmem->regmap)
981 return ERR_PTR(-EINVAL);
983 buf = kzalloc(cell->bytes, GFP_KERNEL);
985 return ERR_PTR(-ENOMEM);
987 rc = __nvmem_cell_read(nvmem, cell, buf, len);
988 if (IS_ERR_VALUE(rc)) {
995 EXPORT_SYMBOL_GPL(nvmem_cell_read);
997 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1000 struct nvmem_device *nvmem = cell->nvmem;
1001 int i, rc, nbits, bit_offset = cell->bit_offset;
1002 u8 v, *p, *buf, *b, pbyte, pbits;
1004 nbits = cell->nbits;
1005 buf = kzalloc(cell->bytes, GFP_KERNEL);
1007 return ERR_PTR(-ENOMEM);
1009 memcpy(buf, _buf, len);
1016 /* setup the first byte with lsb bits from nvmem */
1017 rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
1018 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1020 /* setup rest of the byte if any */
1021 for (i = 1; i < cell->bytes; i++) {
1022 /* Get last byte bits and shift them towards lsb */
1023 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1031 /* if it's not end on byte boundary */
1032 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1033 /* setup the last byte with msb bits from nvmem */
1034 rc = regmap_raw_read(nvmem->regmap,
1035 cell->offset + cell->bytes - 1, &v, 1);
1036 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1044 * nvmem_cell_write() - Write to a given nvmem cell
1046 * @cell: nvmem cell to be written.
1047 * @buf: Buffer to be written.
1048 * @len: length of buffer to be written to nvmem cell.
1050 * Return: length of bytes written or negative on failure.
1052 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1054 struct nvmem_device *nvmem = cell->nvmem;
1057 if (!nvmem || !nvmem->regmap || nvmem->read_only ||
1058 (cell->bit_offset == 0 && len != cell->bytes))
1061 if (cell->bit_offset || cell->nbits) {
1062 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1064 return PTR_ERR(buf);
1067 rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);
1069 /* free the tmp buffer */
1070 if (cell->bit_offset || cell->nbits)
1073 if (IS_ERR_VALUE(rc))
1078 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1081 * nvmem_device_cell_read() - Read a given nvmem device and cell
1083 * @nvmem: nvmem device to read from.
1084 * @info: nvmem cell info to be read.
1085 * @buf: buffer pointer which will be populated on successful read.
1087 * Return: length of successful bytes read on success and negative
1088 * error code on error.
1090 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1091 struct nvmem_cell_info *info, void *buf)
1093 struct nvmem_cell cell;
1097 if (!nvmem || !nvmem->regmap)
1100 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1101 if (IS_ERR_VALUE(rc))
1104 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1105 if (IS_ERR_VALUE(rc))
1110 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1113 * nvmem_device_cell_write() - Write cell to a given nvmem device
1115 * @nvmem: nvmem device to be written to.
1116 * @info: nvmem cell info to be written
1117 * @buf: buffer to be written to cell.
1119 * Return: length of bytes written or negative error code on failure.
1121 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1122 struct nvmem_cell_info *info, void *buf)
1124 struct nvmem_cell cell;
1127 if (!nvmem || !nvmem->regmap)
1130 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1131 if (IS_ERR_VALUE(rc))
1134 return nvmem_cell_write(&cell, buf, cell.bytes);
1136 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1139 * nvmem_device_read() - Read from a given nvmem device
1141 * @nvmem: nvmem device to read from.
1142 * @offset: offset in nvmem device.
1143 * @bytes: number of bytes to read.
1144 * @buf: buffer pointer which will be populated on successful read.
1146 * Return: length of successful bytes read on success and negative
1147 * error code on error.
1149 int nvmem_device_read(struct nvmem_device *nvmem,
1150 unsigned int offset,
1151 size_t bytes, void *buf)
1155 if (!nvmem || !nvmem->regmap)
1158 rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);
1160 if (IS_ERR_VALUE(rc))
1165 EXPORT_SYMBOL_GPL(nvmem_device_read);
1168 * nvmem_device_write() - Write cell to a given nvmem device
1170 * @nvmem: nvmem device to be written to.
1171 * @offset: offset in nvmem device.
1172 * @bytes: number of bytes to write.
1173 * @buf: buffer to be written.
1175 * Return: length of bytes written or negative error code on failure.
1177 int nvmem_device_write(struct nvmem_device *nvmem,
1178 unsigned int offset,
1179 size_t bytes, void *buf)
1183 if (!nvmem || !nvmem->regmap)
1186 rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);
1188 if (IS_ERR_VALUE(rc))
1194 EXPORT_SYMBOL_GPL(nvmem_device_write);
1196 static int __init nvmem_init(void)
1198 return bus_register(&nvmem_bus_type);
1201 static void __exit nvmem_exit(void)
1203 bus_unregister(&nvmem_bus_type);
1206 subsys_initcall(nvmem_init);
1207 module_exit(nvmem_exit);
1209 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1210 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1211 MODULE_DESCRIPTION("nvmem Driver Core");
1212 MODULE_LICENSE("GPL v2");