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);
357 * nvmem_add_cells() - Add cell information to an nvmem device
359 * @nvmem: nvmem device to add cells to.
360 * @info: nvmem cell info to add to the device
361 * @ncells: number of cells in info
363 * Return: 0 or negative error code on failure.
365 int nvmem_add_cells(struct nvmem_device *nvmem,
366 const struct nvmem_cell_info *info,
369 struct nvmem_cell **cells;
372 cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
376 for (i = 0; i < ncells; i++) {
377 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
383 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
389 nvmem_cell_add(cells[i]);
392 nvmem->ncells = ncells;
393 /* remove tmp array */
399 nvmem_cell_drop(cells[i]);
405 EXPORT_SYMBOL_GPL(nvmem_add_cells);
408 * nvmem_setup_compat() - Create an additional binary entry in
409 * drivers sys directory, to be backwards compatible with the older
410 * drivers/misc/eeprom drivers.
412 static int nvmem_setup_compat(struct nvmem_device *nvmem,
413 const struct nvmem_config *config)
417 if (!config->base_dev)
420 if (nvmem->read_only)
421 nvmem->eeprom = bin_attr_ro_root_nvmem;
423 nvmem->eeprom = bin_attr_rw_root_nvmem;
424 nvmem->eeprom.attr.name = "eeprom";
425 nvmem->eeprom.size = nvmem->size;
426 #ifdef CONFIG_DEBUG_LOCK_ALLOC
427 nvmem->eeprom.attr.key = &eeprom_lock_key;
429 nvmem->eeprom.private = &nvmem->dev;
430 nvmem->base_dev = config->base_dev;
432 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
435 "Failed to create eeprom binary file %d\n", rval);
439 nvmem->flags |= FLAG_COMPAT;
445 * nvmem_register() - Register a nvmem device for given nvmem_config.
446 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
448 * @config: nvmem device configuration with which nvmem device is created.
450 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
454 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
456 struct nvmem_device *nvmem;
460 return ERR_PTR(-EINVAL);
462 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
464 return ERR_PTR(-ENOMEM);
466 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
469 return ERR_PTR(rval);
473 nvmem->owner = config->owner;
474 if (!nvmem->owner && config->dev->driver)
475 nvmem->owner = config->dev->driver->owner;
476 nvmem->stride = config->stride ?: 1;
477 nvmem->word_size = config->word_size ?: 1;
478 nvmem->size = config->size;
479 nvmem->dev.type = &nvmem_provider_type;
480 nvmem->dev.bus = &nvmem_bus_type;
481 nvmem->dev.parent = config->dev;
482 nvmem->priv = config->priv;
483 nvmem->reg_read = config->reg_read;
484 nvmem->reg_write = config->reg_write;
485 nvmem->dev.of_node = config->dev->of_node;
487 if (config->id == -1 && config->name) {
488 dev_set_name(&nvmem->dev, "%s", config->name);
490 dev_set_name(&nvmem->dev, "%s%d",
491 config->name ? : "nvmem",
492 config->name ? config->id : nvmem->id);
495 nvmem->read_only = device_property_present(config->dev, "read-only") |
498 if (config->root_only)
499 nvmem->dev.groups = nvmem->read_only ?
500 nvmem_ro_root_dev_groups :
501 nvmem_rw_root_dev_groups;
503 nvmem->dev.groups = nvmem->read_only ?
504 nvmem_ro_dev_groups :
507 device_initialize(&nvmem->dev);
509 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
511 rval = device_add(&nvmem->dev);
515 if (config->compat) {
516 rval = nvmem_setup_compat(nvmem, config);
522 nvmem_add_cells(nvmem, config->cells, config->ncells);
527 device_del(&nvmem->dev);
529 put_device(&nvmem->dev);
531 return ERR_PTR(rval);
533 EXPORT_SYMBOL_GPL(nvmem_register);
536 * nvmem_unregister() - Unregister previously registered nvmem device
538 * @nvmem: Pointer to previously registered nvmem device.
540 * Return: Will be an negative on error or a zero on success.
542 int nvmem_unregister(struct nvmem_device *nvmem)
544 mutex_lock(&nvmem_mutex);
546 mutex_unlock(&nvmem_mutex);
549 mutex_unlock(&nvmem_mutex);
551 if (nvmem->flags & FLAG_COMPAT)
552 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
554 nvmem_device_remove_all_cells(nvmem);
555 device_del(&nvmem->dev);
556 put_device(&nvmem->dev);
560 EXPORT_SYMBOL_GPL(nvmem_unregister);
562 static void devm_nvmem_release(struct device *dev, void *res)
564 WARN_ON(nvmem_unregister(*(struct nvmem_device **)res));
568 * devm_nvmem_register() - Register a managed nvmem device for given
570 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
572 * @dev: Device that uses the nvmem device.
573 * @config: nvmem device configuration with which nvmem device is created.
575 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
578 struct nvmem_device *devm_nvmem_register(struct device *dev,
579 const struct nvmem_config *config)
581 struct nvmem_device **ptr, *nvmem;
583 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
585 return ERR_PTR(-ENOMEM);
587 nvmem = nvmem_register(config);
589 if (!IS_ERR(nvmem)) {
591 devres_add(dev, ptr);
598 EXPORT_SYMBOL_GPL(devm_nvmem_register);
600 static int devm_nvmem_match(struct device *dev, void *res, void *data)
602 struct nvmem_device **r = res;
608 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
611 * @dev: Device that uses the nvmem device.
612 * @nvmem: Pointer to previously registered nvmem device.
614 * Return: Will be an negative on error or a zero on success.
616 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
618 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
620 EXPORT_SYMBOL(devm_nvmem_unregister);
623 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
624 struct nvmem_cell **cellp,
627 struct nvmem_device *nvmem = NULL;
629 mutex_lock(&nvmem_mutex);
632 nvmem = of_nvmem_find(np);
634 mutex_unlock(&nvmem_mutex);
635 return ERR_PTR(-EPROBE_DEFER);
638 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
646 mutex_unlock(&nvmem_mutex);
647 return ERR_PTR(-ENOENT);
652 mutex_unlock(&nvmem_mutex);
654 if (!try_module_get(nvmem->owner)) {
656 "could not increase module refcount for cell %s\n",
659 mutex_lock(&nvmem_mutex);
661 mutex_unlock(&nvmem_mutex);
663 return ERR_PTR(-EINVAL);
669 static void __nvmem_device_put(struct nvmem_device *nvmem)
671 module_put(nvmem->owner);
672 mutex_lock(&nvmem_mutex);
674 mutex_unlock(&nvmem_mutex);
677 static struct nvmem_device *nvmem_find(const char *name)
681 d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
686 return to_nvmem_device(d);
689 #if IS_ENABLED(CONFIG_OF)
691 * of_nvmem_device_get() - Get nvmem device from a given id
693 * @np: Device tree node that uses the nvmem device.
694 * @id: nvmem name from nvmem-names property.
696 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
699 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
702 struct device_node *nvmem_np;
705 index = of_property_match_string(np, "nvmem-names", id);
707 nvmem_np = of_parse_phandle(np, "nvmem", index);
709 return ERR_PTR(-EINVAL);
711 return __nvmem_device_get(nvmem_np, NULL, NULL);
713 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
717 * nvmem_device_get() - Get nvmem device from a given id
719 * @dev: Device that uses the nvmem device.
720 * @dev_name: name of the requested nvmem device.
722 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
725 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
727 if (dev->of_node) { /* try dt first */
728 struct nvmem_device *nvmem;
730 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
732 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
737 return nvmem_find(dev_name);
739 EXPORT_SYMBOL_GPL(nvmem_device_get);
741 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
743 struct nvmem_device **nvmem = res;
745 if (WARN_ON(!nvmem || !*nvmem))
748 return *nvmem == data;
751 static void devm_nvmem_device_release(struct device *dev, void *res)
753 nvmem_device_put(*(struct nvmem_device **)res);
757 * devm_nvmem_device_put() - put alredy got nvmem device
759 * @dev: Device that uses the nvmem device.
760 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
761 * that needs to be released.
763 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
767 ret = devres_release(dev, devm_nvmem_device_release,
768 devm_nvmem_device_match, nvmem);
772 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
775 * nvmem_device_put() - put alredy got nvmem device
777 * @nvmem: pointer to nvmem device that needs to be released.
779 void nvmem_device_put(struct nvmem_device *nvmem)
781 __nvmem_device_put(nvmem);
783 EXPORT_SYMBOL_GPL(nvmem_device_put);
786 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
788 * @dev: Device that requests the nvmem device.
789 * @id: name id for the requested nvmem device.
791 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
792 * on success. The nvmem_cell will be freed by the automatically once the
795 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
797 struct nvmem_device **ptr, *nvmem;
799 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
801 return ERR_PTR(-ENOMEM);
803 nvmem = nvmem_device_get(dev, id);
804 if (!IS_ERR(nvmem)) {
806 devres_add(dev, ptr);
813 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
815 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
817 struct nvmem_cell *cell = NULL;
818 struct nvmem_device *nvmem;
820 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
822 return ERR_CAST(nvmem);
827 #if IS_ENABLED(CONFIG_OF)
829 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
831 * @np: Device tree node that uses the nvmem cell.
832 * @name: nvmem cell name from nvmem-cell-names property, or NULL
833 * for the cell at index 0 (the lone cell with no accompanying
834 * nvmem-cell-names property).
836 * Return: Will be an ERR_PTR() on error or a valid pointer
837 * to a struct nvmem_cell. The nvmem_cell will be freed by the
840 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
843 struct device_node *cell_np, *nvmem_np;
844 struct nvmem_cell *cell;
845 struct nvmem_device *nvmem;
850 /* if cell name exists, find index to the name */
852 index = of_property_match_string(np, "nvmem-cell-names", name);
854 cell_np = of_parse_phandle(np, "nvmem-cells", index);
856 return ERR_PTR(-EINVAL);
858 nvmem_np = of_get_next_parent(cell_np);
860 return ERR_PTR(-EINVAL);
862 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
863 of_node_put(nvmem_np);
865 return ERR_CAST(nvmem);
867 addr = of_get_property(cell_np, "reg", &len);
868 if (!addr || (len < 2 * sizeof(u32))) {
869 dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n",
875 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
882 cell->offset = be32_to_cpup(addr++);
883 cell->bytes = be32_to_cpup(addr);
884 cell->name = cell_np->name;
886 addr = of_get_property(cell_np, "bits", &len);
887 if (addr && len == (2 * sizeof(u32))) {
888 cell->bit_offset = be32_to_cpup(addr++);
889 cell->nbits = be32_to_cpup(addr);
893 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
896 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
898 "cell %s unaligned to nvmem stride %d\n",
899 cell->name, nvmem->stride);
904 nvmem_cell_add(cell);
912 __nvmem_device_put(nvmem);
914 return ERR_PTR(rval);
916 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
920 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
922 * @dev: Device that requests the nvmem cell.
923 * @cell_id: nvmem cell name to get.
925 * Return: Will be an ERR_PTR() on error or a valid pointer
926 * to a struct nvmem_cell. The nvmem_cell will be freed by the
929 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
931 struct nvmem_cell *cell;
933 if (dev->of_node) { /* try dt first */
934 cell = of_nvmem_cell_get(dev->of_node, cell_id);
935 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
939 /* NULL cell_id only allowed for device tree; invalid otherwise */
941 return ERR_PTR(-EINVAL);
943 return nvmem_cell_get_from_list(cell_id);
945 EXPORT_SYMBOL_GPL(nvmem_cell_get);
947 static void devm_nvmem_cell_release(struct device *dev, void *res)
949 nvmem_cell_put(*(struct nvmem_cell **)res);
953 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
955 * @dev: Device that requests the nvmem cell.
956 * @id: nvmem cell name id to get.
958 * Return: Will be an ERR_PTR() on error or a valid pointer
959 * to a struct nvmem_cell. The nvmem_cell will be freed by the
960 * automatically once the device is freed.
962 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
964 struct nvmem_cell **ptr, *cell;
966 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
968 return ERR_PTR(-ENOMEM);
970 cell = nvmem_cell_get(dev, id);
973 devres_add(dev, ptr);
980 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
982 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
984 struct nvmem_cell **c = res;
986 if (WARN_ON(!c || !*c))
993 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
994 * from devm_nvmem_cell_get.
996 * @dev: Device that requests the nvmem cell.
997 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
999 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1003 ret = devres_release(dev, devm_nvmem_cell_release,
1004 devm_nvmem_cell_match, cell);
1008 EXPORT_SYMBOL(devm_nvmem_cell_put);
1011 * nvmem_cell_put() - Release previously allocated nvmem cell.
1013 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1015 void nvmem_cell_put(struct nvmem_cell *cell)
1017 struct nvmem_device *nvmem = cell->nvmem;
1019 __nvmem_device_put(nvmem);
1020 nvmem_cell_drop(cell);
1022 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1024 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
1027 int i, bit_offset = cell->bit_offset;
1032 *b++ >>= bit_offset;
1034 /* setup rest of the bytes if any */
1035 for (i = 1; i < cell->bytes; i++) {
1036 /* Get bits from next byte and shift them towards msb */
1037 *p |= *b << (BITS_PER_BYTE - bit_offset);
1040 *b++ >>= bit_offset;
1043 /* result fits in less bytes */
1044 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
1047 /* clear msb bits if any leftover in the last byte */
1048 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
1051 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1052 struct nvmem_cell *cell,
1053 void *buf, size_t *len)
1057 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1062 /* shift bits in-place */
1063 if (cell->bit_offset || cell->nbits)
1064 nvmem_shift_read_buffer_in_place(cell, buf);
1073 * nvmem_cell_read() - Read a given nvmem cell
1075 * @cell: nvmem cell to be read.
1076 * @len: pointer to length of cell which will be populated on successful read;
1079 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1080 * buffer should be freed by the consumer with a kfree().
1082 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1084 struct nvmem_device *nvmem = cell->nvmem;
1089 return ERR_PTR(-EINVAL);
1091 buf = kzalloc(cell->bytes, GFP_KERNEL);
1093 return ERR_PTR(-ENOMEM);
1095 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1103 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1105 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1108 struct nvmem_device *nvmem = cell->nvmem;
1109 int i, rc, nbits, bit_offset = cell->bit_offset;
1110 u8 v, *p, *buf, *b, pbyte, pbits;
1112 nbits = cell->nbits;
1113 buf = kzalloc(cell->bytes, GFP_KERNEL);
1115 return ERR_PTR(-ENOMEM);
1117 memcpy(buf, _buf, len);
1124 /* setup the first byte with lsb bits from nvmem */
1125 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1128 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1130 /* setup rest of the byte if any */
1131 for (i = 1; i < cell->bytes; i++) {
1132 /* Get last byte bits and shift them towards lsb */
1133 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1141 /* if it's not end on byte boundary */
1142 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1143 /* setup the last byte with msb bits from nvmem */
1144 rc = nvmem_reg_read(nvmem,
1145 cell->offset + cell->bytes - 1, &v, 1);
1148 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1159 * nvmem_cell_write() - Write to a given nvmem cell
1161 * @cell: nvmem cell to be written.
1162 * @buf: Buffer to be written.
1163 * @len: length of buffer to be written to nvmem cell.
1165 * Return: length of bytes written or negative on failure.
1167 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1169 struct nvmem_device *nvmem = cell->nvmem;
1172 if (!nvmem || nvmem->read_only ||
1173 (cell->bit_offset == 0 && len != cell->bytes))
1176 if (cell->bit_offset || cell->nbits) {
1177 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1179 return PTR_ERR(buf);
1182 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1184 /* free the tmp buffer */
1185 if (cell->bit_offset || cell->nbits)
1193 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1196 * nvmem_cell_read_u32() - Read a cell value as an u32
1198 * @dev: Device that requests the nvmem cell.
1199 * @cell_id: Name of nvmem cell to read.
1200 * @val: pointer to output value.
1202 * Return: 0 on success or negative errno.
1204 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1206 struct nvmem_cell *cell;
1210 cell = nvmem_cell_get(dev, cell_id);
1212 return PTR_ERR(cell);
1214 buf = nvmem_cell_read(cell, &len);
1216 nvmem_cell_put(cell);
1217 return PTR_ERR(buf);
1219 if (len != sizeof(*val)) {
1221 nvmem_cell_put(cell);
1224 memcpy(val, buf, sizeof(*val));
1227 nvmem_cell_put(cell);
1230 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1233 * nvmem_device_cell_read() - Read a given nvmem device and cell
1235 * @nvmem: nvmem device to read from.
1236 * @info: nvmem cell info to be read.
1237 * @buf: buffer pointer which will be populated on successful read.
1239 * Return: length of successful bytes read on success and negative
1240 * error code on error.
1242 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1243 struct nvmem_cell_info *info, void *buf)
1245 struct nvmem_cell cell;
1252 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1256 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1262 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1265 * nvmem_device_cell_write() - Write cell to a given nvmem device
1267 * @nvmem: nvmem device to be written to.
1268 * @info: nvmem cell info to be written.
1269 * @buf: buffer to be written to cell.
1271 * Return: length of bytes written or negative error code on failure.
1273 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1274 struct nvmem_cell_info *info, void *buf)
1276 struct nvmem_cell cell;
1282 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1286 return nvmem_cell_write(&cell, buf, cell.bytes);
1288 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1291 * nvmem_device_read() - Read from a given nvmem device
1293 * @nvmem: nvmem device to read from.
1294 * @offset: offset in nvmem device.
1295 * @bytes: number of bytes to read.
1296 * @buf: buffer pointer which will be populated on successful read.
1298 * Return: length of successful bytes read on success and negative
1299 * error code on error.
1301 int nvmem_device_read(struct nvmem_device *nvmem,
1302 unsigned int offset,
1303 size_t bytes, void *buf)
1310 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1317 EXPORT_SYMBOL_GPL(nvmem_device_read);
1320 * nvmem_device_write() - Write cell to a given nvmem device
1322 * @nvmem: nvmem device to be written to.
1323 * @offset: offset in nvmem device.
1324 * @bytes: number of bytes to write.
1325 * @buf: buffer to be written.
1327 * Return: length of bytes written or negative error code on failure.
1329 int nvmem_device_write(struct nvmem_device *nvmem,
1330 unsigned int offset,
1331 size_t bytes, void *buf)
1338 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1346 EXPORT_SYMBOL_GPL(nvmem_device_write);
1348 static int __init nvmem_init(void)
1350 return bus_register(&nvmem_bus_type);
1353 static void __exit nvmem_exit(void)
1355 bus_unregister(&nvmem_bus_type);
1358 subsys_initcall(nvmem_init);
1359 module_exit(nvmem_exit);
1361 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1362 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1363 MODULE_DESCRIPTION("nvmem Driver Core");
1364 MODULE_LICENSE("GPL v2");