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/slab.h>
40 struct bin_attribute eeprom;
41 struct device *base_dev;
42 nvmem_reg_read_t reg_read;
43 nvmem_reg_write_t reg_write;
47 #define FLAG_COMPAT BIT(0)
55 struct nvmem_device *nvmem;
56 struct list_head node;
59 static DEFINE_MUTEX(nvmem_mutex);
60 static DEFINE_IDA(nvmem_ida);
62 static LIST_HEAD(nvmem_cells);
63 static DEFINE_MUTEX(nvmem_cells_mutex);
65 #ifdef CONFIG_DEBUG_LOCK_ALLOC
66 static struct lock_class_key eeprom_lock_key;
69 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
70 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
71 void *val, size_t bytes)
74 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
79 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
80 void *val, size_t bytes)
83 return nvmem->reg_write(nvmem->priv, offset, val, bytes);
88 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
89 struct bin_attribute *attr,
90 char *buf, loff_t pos, size_t count)
93 struct nvmem_device *nvmem;
99 dev = container_of(kobj, struct device, kobj);
100 nvmem = to_nvmem_device(dev);
102 /* Stop the user from reading */
103 if (pos >= nvmem->size)
106 if (count < nvmem->word_size)
109 if (pos + count > nvmem->size)
110 count = nvmem->size - pos;
112 count = round_down(count, nvmem->word_size);
114 rc = nvmem_reg_read(nvmem, pos, buf, count);
122 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
123 struct bin_attribute *attr,
124 char *buf, loff_t pos, size_t count)
127 struct nvmem_device *nvmem;
133 dev = container_of(kobj, struct device, kobj);
134 nvmem = to_nvmem_device(dev);
136 /* Stop the user from writing */
137 if (pos >= nvmem->size)
140 if (count < nvmem->word_size)
143 if (pos + count > nvmem->size)
144 count = nvmem->size - pos;
146 count = round_down(count, nvmem->word_size);
148 rc = nvmem_reg_write(nvmem, pos, buf, count);
156 /* default read/write permissions */
157 static struct bin_attribute bin_attr_rw_nvmem = {
160 .mode = S_IWUSR | S_IRUGO,
162 .read = bin_attr_nvmem_read,
163 .write = bin_attr_nvmem_write,
166 static struct bin_attribute *nvmem_bin_rw_attributes[] = {
171 static const struct attribute_group nvmem_bin_rw_group = {
172 .bin_attrs = nvmem_bin_rw_attributes,
175 static const struct attribute_group *nvmem_rw_dev_groups[] = {
180 /* read only permission */
181 static struct bin_attribute bin_attr_ro_nvmem = {
186 .read = bin_attr_nvmem_read,
189 static struct bin_attribute *nvmem_bin_ro_attributes[] = {
194 static const struct attribute_group nvmem_bin_ro_group = {
195 .bin_attrs = nvmem_bin_ro_attributes,
198 static const struct attribute_group *nvmem_ro_dev_groups[] = {
203 /* default read/write permissions, root only */
204 static struct bin_attribute bin_attr_rw_root_nvmem = {
207 .mode = S_IWUSR | S_IRUSR,
209 .read = bin_attr_nvmem_read,
210 .write = bin_attr_nvmem_write,
213 static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
214 &bin_attr_rw_root_nvmem,
218 static const struct attribute_group nvmem_bin_rw_root_group = {
219 .bin_attrs = nvmem_bin_rw_root_attributes,
222 static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
223 &nvmem_bin_rw_root_group,
227 /* read only permission, root only */
228 static struct bin_attribute bin_attr_ro_root_nvmem = {
233 .read = bin_attr_nvmem_read,
236 static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
237 &bin_attr_ro_root_nvmem,
241 static const struct attribute_group nvmem_bin_ro_root_group = {
242 .bin_attrs = nvmem_bin_ro_root_attributes,
245 static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
246 &nvmem_bin_ro_root_group,
250 static void nvmem_release(struct device *dev)
252 struct nvmem_device *nvmem = to_nvmem_device(dev);
254 ida_simple_remove(&nvmem_ida, nvmem->id);
258 static const struct device_type nvmem_provider_type = {
259 .release = nvmem_release,
262 static struct bus_type nvmem_bus_type = {
266 static int of_nvmem_match(struct device *dev, void *nvmem_np)
268 return dev->of_node == nvmem_np;
271 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
278 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
283 return to_nvmem_device(d);
286 static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
288 struct nvmem_cell *p;
290 mutex_lock(&nvmem_cells_mutex);
292 list_for_each_entry(p, &nvmem_cells, node)
293 if (!strcmp(p->name, cell_id)) {
294 mutex_unlock(&nvmem_cells_mutex);
298 mutex_unlock(&nvmem_cells_mutex);
303 static void nvmem_cell_drop(struct nvmem_cell *cell)
305 mutex_lock(&nvmem_cells_mutex);
306 list_del(&cell->node);
307 mutex_unlock(&nvmem_cells_mutex);
311 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
313 struct nvmem_cell *cell;
314 struct list_head *p, *n;
316 list_for_each_safe(p, n, &nvmem_cells) {
317 cell = list_entry(p, struct nvmem_cell, node);
318 if (cell->nvmem == nvmem)
319 nvmem_cell_drop(cell);
323 static void nvmem_cell_add(struct nvmem_cell *cell)
325 mutex_lock(&nvmem_cells_mutex);
326 list_add_tail(&cell->node, &nvmem_cells);
327 mutex_unlock(&nvmem_cells_mutex);
330 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
331 const struct nvmem_cell_info *info,
332 struct nvmem_cell *cell)
335 cell->offset = info->offset;
336 cell->bytes = info->bytes;
337 cell->name = info->name;
339 cell->bit_offset = info->bit_offset;
340 cell->nbits = info->nbits;
343 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
346 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
348 "cell %s unaligned to nvmem stride %d\n",
349 cell->name, nvmem->stride);
356 static int nvmem_add_cells(struct nvmem_device *nvmem,
357 const struct nvmem_config *cfg)
359 struct nvmem_cell **cells;
360 const struct nvmem_cell_info *info = cfg->cells;
363 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
367 for (i = 0; i < cfg->ncells; i++) {
368 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
374 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
380 nvmem_cell_add(cells[i]);
383 nvmem->ncells = cfg->ncells;
384 /* remove tmp array */
390 nvmem_cell_drop(cells[i]);
398 * nvmem_setup_compat() - Create an additional binary entry in
399 * drivers sys directory, to be backwards compatible with the older
400 * drivers/misc/eeprom drivers.
402 static int nvmem_setup_compat(struct nvmem_device *nvmem,
403 const struct nvmem_config *config)
407 if (!config->base_dev)
410 if (nvmem->read_only) {
411 if (config->root_only)
412 nvmem->eeprom = bin_attr_ro_root_nvmem;
414 nvmem->eeprom = bin_attr_ro_nvmem;
416 if (config->root_only)
417 nvmem->eeprom = bin_attr_rw_root_nvmem;
419 nvmem->eeprom = bin_attr_rw_nvmem;
421 nvmem->eeprom.attr.name = "eeprom";
422 nvmem->eeprom.size = nvmem->size;
423 #ifdef CONFIG_DEBUG_LOCK_ALLOC
424 nvmem->eeprom.attr.key = &eeprom_lock_key;
426 nvmem->eeprom.private = &nvmem->dev;
427 nvmem->base_dev = config->base_dev;
429 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
432 "Failed to create eeprom binary file %d\n", rval);
436 nvmem->flags |= FLAG_COMPAT;
442 * nvmem_register() - Register a nvmem device for given nvmem_config.
443 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
445 * @config: nvmem device configuration with which nvmem device is created.
447 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
451 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
453 struct nvmem_device *nvmem;
454 struct device_node *np;
458 return ERR_PTR(-EINVAL);
460 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
462 return ERR_PTR(-ENOMEM);
464 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
467 return ERR_PTR(rval);
471 nvmem->owner = config->owner;
472 nvmem->stride = config->stride;
473 nvmem->word_size = config->word_size;
474 nvmem->size = config->size;
475 nvmem->dev.type = &nvmem_provider_type;
476 nvmem->dev.bus = &nvmem_bus_type;
477 nvmem->dev.parent = config->dev;
478 nvmem->priv = config->priv;
479 nvmem->reg_read = config->reg_read;
480 nvmem->reg_write = config->reg_write;
481 np = config->dev->of_node;
482 nvmem->dev.of_node = np;
483 dev_set_name(&nvmem->dev, "%s%d",
484 config->name ? : "nvmem",
485 config->name ? config->id : nvmem->id);
487 nvmem->read_only = of_property_read_bool(np, "read-only") |
490 if (config->root_only)
491 nvmem->dev.groups = nvmem->read_only ?
492 nvmem_ro_root_dev_groups :
493 nvmem_rw_root_dev_groups;
495 nvmem->dev.groups = nvmem->read_only ?
496 nvmem_ro_dev_groups :
499 device_initialize(&nvmem->dev);
501 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
503 rval = device_add(&nvmem->dev);
507 if (config->compat) {
508 rval = nvmem_setup_compat(nvmem, config);
514 nvmem_add_cells(nvmem, config);
519 device_del(&nvmem->dev);
521 put_device(&nvmem->dev);
523 return ERR_PTR(rval);
525 EXPORT_SYMBOL_GPL(nvmem_register);
528 * nvmem_unregister() - Unregister previously registered nvmem device
530 * @nvmem: Pointer to previously registered nvmem device.
532 * Return: Will be an negative on error or a zero on success.
534 int nvmem_unregister(struct nvmem_device *nvmem)
536 mutex_lock(&nvmem_mutex);
538 mutex_unlock(&nvmem_mutex);
541 mutex_unlock(&nvmem_mutex);
543 if (nvmem->flags & FLAG_COMPAT)
544 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
546 nvmem_device_remove_all_cells(nvmem);
547 device_del(&nvmem->dev);
548 put_device(&nvmem->dev);
552 EXPORT_SYMBOL_GPL(nvmem_unregister);
554 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
555 struct nvmem_cell **cellp,
558 struct nvmem_device *nvmem = NULL;
560 mutex_lock(&nvmem_mutex);
563 nvmem = of_nvmem_find(np);
565 mutex_unlock(&nvmem_mutex);
566 return ERR_PTR(-EPROBE_DEFER);
569 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
577 mutex_unlock(&nvmem_mutex);
578 return ERR_PTR(-ENOENT);
583 mutex_unlock(&nvmem_mutex);
585 if (!try_module_get(nvmem->owner)) {
587 "could not increase module refcount for cell %s\n",
590 mutex_lock(&nvmem_mutex);
592 mutex_unlock(&nvmem_mutex);
594 return ERR_PTR(-EINVAL);
600 static void __nvmem_device_put(struct nvmem_device *nvmem)
602 module_put(nvmem->owner);
603 mutex_lock(&nvmem_mutex);
605 mutex_unlock(&nvmem_mutex);
608 static int nvmem_match(struct device *dev, void *data)
610 return !strcmp(dev_name(dev), data);
613 static struct nvmem_device *nvmem_find(const char *name)
617 d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
620 return ERR_PTR(-ENOENT);
622 return to_nvmem_device(d);
625 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
627 * of_nvmem_device_get() - Get nvmem device from a given id
629 * @np: Device tree node that uses the nvmem device.
630 * @id: nvmem name from nvmem-names property.
632 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
635 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
638 struct device_node *nvmem_np;
641 index = of_property_match_string(np, "nvmem-names", id);
643 nvmem_np = of_parse_phandle(np, "nvmem", index);
645 return ERR_PTR(-EINVAL);
647 return __nvmem_device_get(nvmem_np, NULL, NULL);
649 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
653 * nvmem_device_get() - Get nvmem device from a given id
655 * @dev: Device that uses the nvmem device.
656 * @dev_name: name of the requested nvmem device.
658 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
661 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
663 if (dev->of_node) { /* try dt first */
664 struct nvmem_device *nvmem;
666 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
668 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
673 return nvmem_find(dev_name);
675 EXPORT_SYMBOL_GPL(nvmem_device_get);
677 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
679 struct nvmem_device **nvmem = res;
681 if (WARN_ON(!nvmem || !*nvmem))
684 return *nvmem == data;
687 static void devm_nvmem_device_release(struct device *dev, void *res)
689 nvmem_device_put(*(struct nvmem_device **)res);
693 * devm_nvmem_device_put() - put alredy got nvmem device
695 * @dev: Device that uses the nvmem device.
696 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
697 * that needs to be released.
699 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
703 ret = devres_release(dev, devm_nvmem_device_release,
704 devm_nvmem_device_match, nvmem);
708 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
711 * nvmem_device_put() - put alredy got nvmem device
713 * @nvmem: pointer to nvmem device that needs to be released.
715 void nvmem_device_put(struct nvmem_device *nvmem)
717 __nvmem_device_put(nvmem);
719 EXPORT_SYMBOL_GPL(nvmem_device_put);
722 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
724 * @dev: Device that requests the nvmem device.
725 * @id: name id for the requested nvmem device.
727 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
728 * on success. The nvmem_cell will be freed by the automatically once the
731 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
733 struct nvmem_device **ptr, *nvmem;
735 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
737 return ERR_PTR(-ENOMEM);
739 nvmem = nvmem_device_get(dev, id);
740 if (!IS_ERR(nvmem)) {
742 devres_add(dev, ptr);
749 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
751 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
753 struct nvmem_cell *cell = NULL;
754 struct nvmem_device *nvmem;
756 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
758 return ERR_CAST(nvmem);
763 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
765 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
767 * @np: Device tree node that uses the nvmem cell.
768 * @name: nvmem cell name from nvmem-cell-names property, or NULL
769 * for the cell at index 0 (the lone cell with no accompanying
770 * nvmem-cell-names property).
772 * Return: Will be an ERR_PTR() on error or a valid pointer
773 * to a struct nvmem_cell. The nvmem_cell will be freed by the
776 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
779 struct device_node *cell_np, *nvmem_np;
780 struct nvmem_cell *cell;
781 struct nvmem_device *nvmem;
786 /* if cell name exists, find index to the name */
788 index = of_property_match_string(np, "nvmem-cell-names", name);
790 cell_np = of_parse_phandle(np, "nvmem-cells", index);
792 return ERR_PTR(-EINVAL);
794 nvmem_np = of_get_next_parent(cell_np);
796 return ERR_PTR(-EINVAL);
798 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
799 of_node_put(nvmem_np);
801 return ERR_CAST(nvmem);
803 addr = of_get_property(cell_np, "reg", &len);
804 if (!addr || (len < 2 * sizeof(u32))) {
805 dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n",
811 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
818 cell->offset = be32_to_cpup(addr++);
819 cell->bytes = be32_to_cpup(addr);
820 cell->name = cell_np->name;
822 addr = of_get_property(cell_np, "bits", &len);
823 if (addr && len == (2 * sizeof(u32))) {
824 cell->bit_offset = be32_to_cpup(addr++);
825 cell->nbits = be32_to_cpup(addr);
829 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
832 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
834 "cell %s unaligned to nvmem stride %d\n",
835 cell->name, nvmem->stride);
840 nvmem_cell_add(cell);
848 __nvmem_device_put(nvmem);
850 return ERR_PTR(rval);
852 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
856 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
858 * @dev: Device that requests the nvmem cell.
859 * @cell_id: nvmem cell name to get.
861 * Return: Will be an ERR_PTR() on error or a valid pointer
862 * to a struct nvmem_cell. The nvmem_cell will be freed by the
865 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
867 struct nvmem_cell *cell;
869 if (dev->of_node) { /* try dt first */
870 cell = of_nvmem_cell_get(dev->of_node, cell_id);
871 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
875 /* NULL cell_id only allowed for device tree; invalid otherwise */
877 return ERR_PTR(-EINVAL);
879 return nvmem_cell_get_from_list(cell_id);
881 EXPORT_SYMBOL_GPL(nvmem_cell_get);
883 static void devm_nvmem_cell_release(struct device *dev, void *res)
885 nvmem_cell_put(*(struct nvmem_cell **)res);
889 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
891 * @dev: Device that requests the nvmem cell.
892 * @id: nvmem cell name id to get.
894 * Return: Will be an ERR_PTR() on error or a valid pointer
895 * to a struct nvmem_cell. The nvmem_cell will be freed by the
896 * automatically once the device is freed.
898 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
900 struct nvmem_cell **ptr, *cell;
902 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
904 return ERR_PTR(-ENOMEM);
906 cell = nvmem_cell_get(dev, id);
909 devres_add(dev, ptr);
916 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
918 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
920 struct nvmem_cell **c = res;
922 if (WARN_ON(!c || !*c))
929 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
930 * from devm_nvmem_cell_get.
932 * @dev: Device that requests the nvmem cell.
933 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
935 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
939 ret = devres_release(dev, devm_nvmem_cell_release,
940 devm_nvmem_cell_match, cell);
944 EXPORT_SYMBOL(devm_nvmem_cell_put);
947 * nvmem_cell_put() - Release previously allocated nvmem cell.
949 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
951 void nvmem_cell_put(struct nvmem_cell *cell)
953 struct nvmem_device *nvmem = cell->nvmem;
955 __nvmem_device_put(nvmem);
956 nvmem_cell_drop(cell);
958 EXPORT_SYMBOL_GPL(nvmem_cell_put);
960 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
964 int i, extra, bit_offset = cell->bit_offset;
971 /* setup rest of the bytes if any */
972 for (i = 1; i < cell->bytes; i++) {
973 /* Get bits from next byte and shift them towards msb */
974 *p |= *b << (BITS_PER_BYTE - bit_offset);
980 /* point to the msb */
981 p += cell->bytes - 1;
984 /* result fits in less bytes */
985 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
989 /* clear msb bits if any leftover in the last byte */
990 if (cell->nbits % BITS_PER_BYTE)
991 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
994 static int __nvmem_cell_read(struct nvmem_device *nvmem,
995 struct nvmem_cell *cell,
996 void *buf, size_t *len)
1000 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1005 /* shift bits in-place */
1006 if (cell->bit_offset || cell->nbits)
1007 nvmem_shift_read_buffer_in_place(cell, buf);
1016 * nvmem_cell_read() - Read a given nvmem cell
1018 * @cell: nvmem cell to be read.
1019 * @len: pointer to length of cell which will be populated on successful read;
1022 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1023 * buffer should be freed by the consumer with a kfree().
1025 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1027 struct nvmem_device *nvmem = cell->nvmem;
1032 return ERR_PTR(-EINVAL);
1034 buf = kzalloc(cell->bytes, GFP_KERNEL);
1036 return ERR_PTR(-ENOMEM);
1038 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1046 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1048 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1051 struct nvmem_device *nvmem = cell->nvmem;
1052 int i, rc, nbits, bit_offset = cell->bit_offset;
1053 u8 v, *p, *buf, *b, pbyte, pbits;
1055 nbits = cell->nbits;
1056 buf = kzalloc(cell->bytes, GFP_KERNEL);
1058 return ERR_PTR(-ENOMEM);
1060 memcpy(buf, _buf, len);
1067 /* setup the first byte with lsb bits from nvmem */
1068 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1071 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1073 /* setup rest of the byte if any */
1074 for (i = 1; i < cell->bytes; i++) {
1075 /* Get last byte bits and shift them towards lsb */
1076 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1084 /* if it's not end on byte boundary */
1085 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1086 /* setup the last byte with msb bits from nvmem */
1087 rc = nvmem_reg_read(nvmem,
1088 cell->offset + cell->bytes - 1, &v, 1);
1091 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1102 * nvmem_cell_write() - Write to a given nvmem cell
1104 * @cell: nvmem cell to be written.
1105 * @buf: Buffer to be written.
1106 * @len: length of buffer to be written to nvmem cell.
1108 * Return: length of bytes written or negative on failure.
1110 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1112 struct nvmem_device *nvmem = cell->nvmem;
1115 if (!nvmem || nvmem->read_only ||
1116 (cell->bit_offset == 0 && len != cell->bytes))
1119 if (cell->bit_offset || cell->nbits) {
1120 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1122 return PTR_ERR(buf);
1125 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1127 /* free the tmp buffer */
1128 if (cell->bit_offset || cell->nbits)
1136 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1139 * nvmem_cell_read_u32() - Read a cell value as an u32
1141 * @dev: Device that requests the nvmem cell.
1142 * @cell_id: Name of nvmem cell to read.
1143 * @val: pointer to output value.
1145 * Return: 0 on success or negative errno.
1147 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1149 struct nvmem_cell *cell;
1153 cell = nvmem_cell_get(dev, cell_id);
1155 return PTR_ERR(cell);
1157 buf = nvmem_cell_read(cell, &len);
1159 nvmem_cell_put(cell);
1160 return PTR_ERR(buf);
1162 if (len != sizeof(*val)) {
1164 nvmem_cell_put(cell);
1167 memcpy(val, buf, sizeof(*val));
1170 nvmem_cell_put(cell);
1173 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1176 * nvmem_device_cell_read() - Read a given nvmem device and cell
1178 * @nvmem: nvmem device to read from.
1179 * @info: nvmem cell info to be read.
1180 * @buf: buffer pointer which will be populated on successful read.
1182 * Return: length of successful bytes read on success and negative
1183 * error code on error.
1185 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1186 struct nvmem_cell_info *info, void *buf)
1188 struct nvmem_cell cell;
1195 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1199 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1205 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1208 * nvmem_device_cell_write() - Write cell to a given nvmem device
1210 * @nvmem: nvmem device to be written to.
1211 * @info: nvmem cell info to be written.
1212 * @buf: buffer to be written to cell.
1214 * Return: length of bytes written or negative error code on failure.
1216 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1217 struct nvmem_cell_info *info, void *buf)
1219 struct nvmem_cell cell;
1225 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1229 return nvmem_cell_write(&cell, buf, cell.bytes);
1231 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1234 * nvmem_device_read() - Read from a given nvmem device
1236 * @nvmem: nvmem device to read from.
1237 * @offset: offset in nvmem device.
1238 * @bytes: number of bytes to read.
1239 * @buf: buffer pointer which will be populated on successful read.
1241 * Return: length of successful bytes read on success and negative
1242 * error code on error.
1244 int nvmem_device_read(struct nvmem_device *nvmem,
1245 unsigned int offset,
1246 size_t bytes, void *buf)
1253 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1260 EXPORT_SYMBOL_GPL(nvmem_device_read);
1263 * nvmem_device_write() - Write cell to a given nvmem device
1265 * @nvmem: nvmem device to be written to.
1266 * @offset: offset in nvmem device.
1267 * @bytes: number of bytes to write.
1268 * @buf: buffer to be written.
1270 * Return: length of bytes written or negative error code on failure.
1272 int nvmem_device_write(struct nvmem_device *nvmem,
1273 unsigned int offset,
1274 size_t bytes, void *buf)
1281 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1289 EXPORT_SYMBOL_GPL(nvmem_device_write);
1291 static int __init nvmem_init(void)
1293 return bus_register(&nvmem_bus_type);
1296 static void __exit nvmem_exit(void)
1298 bus_unregister(&nvmem_bus_type);
1301 subsys_initcall(nvmem_init);
1302 module_exit(nvmem_exit);
1304 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1305 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1306 MODULE_DESCRIPTION("nvmem Driver Core");
1307 MODULE_LICENSE("GPL v2");