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>
39 struct bin_attribute eeprom;
40 struct device *base_dev;
41 nvmem_reg_read_t reg_read;
42 nvmem_reg_write_t reg_write;
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)
69 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
70 void *val, size_t bytes)
73 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
78 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
79 void *val, size_t bytes)
82 return nvmem->reg_write(nvmem->priv, offset, val, bytes);
87 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
88 struct bin_attribute *attr,
89 char *buf, loff_t pos, size_t count)
92 struct nvmem_device *nvmem;
98 dev = container_of(kobj, struct device, kobj);
99 nvmem = to_nvmem_device(dev);
101 /* Stop the user from reading */
102 if (pos >= nvmem->size)
105 if (count < nvmem->word_size)
108 if (pos + count > nvmem->size)
109 count = nvmem->size - pos;
111 count = round_down(count, nvmem->word_size);
113 rc = nvmem_reg_read(nvmem, pos, buf, count);
121 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
122 struct bin_attribute *attr,
123 char *buf, loff_t pos, size_t count)
126 struct nvmem_device *nvmem;
132 dev = container_of(kobj, struct device, kobj);
133 nvmem = to_nvmem_device(dev);
135 /* Stop the user from writing */
136 if (pos >= nvmem->size)
139 if (count < nvmem->word_size)
142 if (pos + count > nvmem->size)
143 count = nvmem->size - pos;
145 count = round_down(count, nvmem->word_size);
147 rc = nvmem_reg_write(nvmem, pos, buf, count);
155 /* default read/write permissions */
156 static struct bin_attribute bin_attr_rw_nvmem = {
159 .mode = S_IWUSR | S_IRUGO,
161 .read = bin_attr_nvmem_read,
162 .write = bin_attr_nvmem_write,
165 static struct bin_attribute *nvmem_bin_rw_attributes[] = {
170 static const struct attribute_group nvmem_bin_rw_group = {
171 .bin_attrs = nvmem_bin_rw_attributes,
174 static const struct attribute_group *nvmem_rw_dev_groups[] = {
179 /* read only permission */
180 static struct bin_attribute bin_attr_ro_nvmem = {
185 .read = bin_attr_nvmem_read,
188 static struct bin_attribute *nvmem_bin_ro_attributes[] = {
193 static const struct attribute_group nvmem_bin_ro_group = {
194 .bin_attrs = nvmem_bin_ro_attributes,
197 static const struct attribute_group *nvmem_ro_dev_groups[] = {
202 /* default read/write permissions, root only */
203 static struct bin_attribute bin_attr_rw_root_nvmem = {
206 .mode = S_IWUSR | S_IRUSR,
208 .read = bin_attr_nvmem_read,
209 .write = bin_attr_nvmem_write,
212 static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
213 &bin_attr_rw_root_nvmem,
217 static const struct attribute_group nvmem_bin_rw_root_group = {
218 .bin_attrs = nvmem_bin_rw_root_attributes,
221 static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
222 &nvmem_bin_rw_root_group,
226 /* read only permission, root only */
227 static struct bin_attribute bin_attr_ro_root_nvmem = {
232 .read = bin_attr_nvmem_read,
235 static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
236 &bin_attr_ro_root_nvmem,
240 static const struct attribute_group nvmem_bin_ro_root_group = {
241 .bin_attrs = nvmem_bin_ro_root_attributes,
244 static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
245 &nvmem_bin_ro_root_group,
249 static void nvmem_release(struct device *dev)
251 struct nvmem_device *nvmem = to_nvmem_device(dev);
253 ida_simple_remove(&nvmem_ida, nvmem->id);
257 static const struct device_type nvmem_provider_type = {
258 .release = nvmem_release,
261 static struct bus_type nvmem_bus_type = {
265 static int of_nvmem_match(struct device *dev, void *nvmem_np)
267 return dev->of_node == nvmem_np;
270 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
277 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
282 return to_nvmem_device(d);
285 static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
287 struct nvmem_cell *p;
289 mutex_lock(&nvmem_cells_mutex);
291 list_for_each_entry(p, &nvmem_cells, node)
292 if (!strcmp(p->name, cell_id)) {
293 mutex_unlock(&nvmem_cells_mutex);
297 mutex_unlock(&nvmem_cells_mutex);
302 static void nvmem_cell_drop(struct nvmem_cell *cell)
304 mutex_lock(&nvmem_cells_mutex);
305 list_del(&cell->node);
306 mutex_unlock(&nvmem_cells_mutex);
310 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
312 struct nvmem_cell *cell;
313 struct list_head *p, *n;
315 list_for_each_safe(p, n, &nvmem_cells) {
316 cell = list_entry(p, struct nvmem_cell, node);
317 if (cell->nvmem == nvmem)
318 nvmem_cell_drop(cell);
322 static void nvmem_cell_add(struct nvmem_cell *cell)
324 mutex_lock(&nvmem_cells_mutex);
325 list_add_tail(&cell->node, &nvmem_cells);
326 mutex_unlock(&nvmem_cells_mutex);
329 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
330 const struct nvmem_cell_info *info,
331 struct nvmem_cell *cell)
334 cell->offset = info->offset;
335 cell->bytes = info->bytes;
336 cell->name = info->name;
338 cell->bit_offset = info->bit_offset;
339 cell->nbits = info->nbits;
342 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
345 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
347 "cell %s unaligned to nvmem stride %d\n",
348 cell->name, nvmem->stride);
356 * nvmem_add_cells() - Add cell information to an nvmem device
358 * @nvmem: nvmem device to add cells to.
359 * @info: nvmem cell info to add to the device
360 * @ncells: number of cells in info
362 * Return: 0 or negative error code on failure.
364 int nvmem_add_cells(struct nvmem_device *nvmem,
365 const struct nvmem_cell_info *info,
368 struct nvmem_cell **cells;
371 cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
375 for (i = 0; i < ncells; i++) {
376 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
382 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
388 nvmem_cell_add(cells[i]);
391 /* remove tmp array */
397 nvmem_cell_drop(cells[i]);
403 EXPORT_SYMBOL_GPL(nvmem_add_cells);
406 * nvmem_setup_compat() - Create an additional binary entry in
407 * drivers sys directory, to be backwards compatible with the older
408 * drivers/misc/eeprom drivers.
410 static int nvmem_setup_compat(struct nvmem_device *nvmem,
411 const struct nvmem_config *config)
415 if (!config->base_dev)
418 if (nvmem->read_only) {
419 if (config->root_only)
420 nvmem->eeprom = bin_attr_ro_root_nvmem;
422 nvmem->eeprom = bin_attr_ro_nvmem;
424 if (config->root_only)
425 nvmem->eeprom = bin_attr_rw_root_nvmem;
427 nvmem->eeprom = bin_attr_rw_nvmem;
429 nvmem->eeprom.attr.name = "eeprom";
430 nvmem->eeprom.size = nvmem->size;
431 #ifdef CONFIG_DEBUG_LOCK_ALLOC
432 nvmem->eeprom.attr.key = &eeprom_lock_key;
434 nvmem->eeprom.private = &nvmem->dev;
435 nvmem->base_dev = config->base_dev;
437 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
440 "Failed to create eeprom binary file %d\n", rval);
444 nvmem->flags |= FLAG_COMPAT;
450 * nvmem_register() - Register a nvmem device for given nvmem_config.
451 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
453 * @config: nvmem device configuration with which nvmem device is created.
455 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
459 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
461 struct nvmem_device *nvmem;
465 return ERR_PTR(-EINVAL);
467 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
469 return ERR_PTR(-ENOMEM);
471 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
474 return ERR_PTR(rval);
478 nvmem->owner = config->owner;
479 if (!nvmem->owner && config->dev->driver)
480 nvmem->owner = config->dev->driver->owner;
481 nvmem->stride = config->stride ?: 1;
482 nvmem->word_size = config->word_size ?: 1;
483 nvmem->size = config->size;
484 nvmem->dev.type = &nvmem_provider_type;
485 nvmem->dev.bus = &nvmem_bus_type;
486 nvmem->dev.parent = config->dev;
487 nvmem->priv = config->priv;
488 nvmem->reg_read = config->reg_read;
489 nvmem->reg_write = config->reg_write;
490 nvmem->dev.of_node = config->dev->of_node;
492 if (config->id == -1 && config->name) {
493 dev_set_name(&nvmem->dev, "%s", config->name);
495 dev_set_name(&nvmem->dev, "%s%d",
496 config->name ? : "nvmem",
497 config->name ? config->id : nvmem->id);
500 nvmem->read_only = device_property_present(config->dev, "read-only") |
503 if (config->root_only)
504 nvmem->dev.groups = nvmem->read_only ?
505 nvmem_ro_root_dev_groups :
506 nvmem_rw_root_dev_groups;
508 nvmem->dev.groups = nvmem->read_only ?
509 nvmem_ro_dev_groups :
512 device_initialize(&nvmem->dev);
514 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
516 rval = device_add(&nvmem->dev);
520 if (config->compat) {
521 rval = nvmem_setup_compat(nvmem, config);
527 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
529 goto err_teardown_compat;
536 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
538 device_del(&nvmem->dev);
540 put_device(&nvmem->dev);
542 return ERR_PTR(rval);
544 EXPORT_SYMBOL_GPL(nvmem_register);
547 * nvmem_unregister() - Unregister previously registered nvmem device
549 * @nvmem: Pointer to previously registered nvmem device.
551 * Return: Will be an negative on error or a zero on success.
553 int nvmem_unregister(struct nvmem_device *nvmem)
555 mutex_lock(&nvmem_mutex);
557 mutex_unlock(&nvmem_mutex);
560 mutex_unlock(&nvmem_mutex);
562 if (nvmem->flags & FLAG_COMPAT)
563 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
565 nvmem_device_remove_all_cells(nvmem);
566 device_del(&nvmem->dev);
567 put_device(&nvmem->dev);
571 EXPORT_SYMBOL_GPL(nvmem_unregister);
573 static void devm_nvmem_release(struct device *dev, void *res)
575 WARN_ON(nvmem_unregister(*(struct nvmem_device **)res));
579 * devm_nvmem_register() - Register a managed nvmem device for given
581 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
583 * @dev: Device that uses the nvmem device.
584 * @config: nvmem device configuration with which nvmem device is created.
586 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
589 struct nvmem_device *devm_nvmem_register(struct device *dev,
590 const struct nvmem_config *config)
592 struct nvmem_device **ptr, *nvmem;
594 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
596 return ERR_PTR(-ENOMEM);
598 nvmem = nvmem_register(config);
600 if (!IS_ERR(nvmem)) {
602 devres_add(dev, ptr);
609 EXPORT_SYMBOL_GPL(devm_nvmem_register);
611 static int devm_nvmem_match(struct device *dev, void *res, void *data)
613 struct nvmem_device **r = res;
619 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
622 * @dev: Device that uses the nvmem device.
623 * @nvmem: Pointer to previously registered nvmem device.
625 * Return: Will be an negative on error or a zero on success.
627 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
629 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
631 EXPORT_SYMBOL(devm_nvmem_unregister);
634 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
635 struct nvmem_cell **cellp,
638 struct nvmem_device *nvmem = NULL;
640 mutex_lock(&nvmem_mutex);
643 nvmem = of_nvmem_find(np);
645 mutex_unlock(&nvmem_mutex);
646 return ERR_PTR(-EPROBE_DEFER);
649 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
657 mutex_unlock(&nvmem_mutex);
658 return ERR_PTR(-ENOENT);
663 mutex_unlock(&nvmem_mutex);
665 if (!try_module_get(nvmem->owner)) {
667 "could not increase module refcount for cell %s\n",
670 mutex_lock(&nvmem_mutex);
672 mutex_unlock(&nvmem_mutex);
674 return ERR_PTR(-EINVAL);
680 static void __nvmem_device_put(struct nvmem_device *nvmem)
682 module_put(nvmem->owner);
683 mutex_lock(&nvmem_mutex);
685 mutex_unlock(&nvmem_mutex);
688 static struct nvmem_device *nvmem_find(const char *name)
692 d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
695 return ERR_PTR(-ENOENT);
697 return to_nvmem_device(d);
700 #if IS_ENABLED(CONFIG_OF)
702 * of_nvmem_device_get() - Get nvmem device from a given id
704 * @np: Device tree node that uses the nvmem device.
705 * @id: nvmem name from nvmem-names property.
707 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
710 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
713 struct device_node *nvmem_np;
716 index = of_property_match_string(np, "nvmem-names", id);
718 nvmem_np = of_parse_phandle(np, "nvmem", index);
720 return ERR_PTR(-EINVAL);
722 return __nvmem_device_get(nvmem_np, NULL, NULL);
724 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
728 * nvmem_device_get() - Get nvmem device from a given id
730 * @dev: Device that uses the nvmem device.
731 * @dev_name: name of the requested nvmem device.
733 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
736 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
738 if (dev->of_node) { /* try dt first */
739 struct nvmem_device *nvmem;
741 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
743 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
748 return nvmem_find(dev_name);
750 EXPORT_SYMBOL_GPL(nvmem_device_get);
752 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
754 struct nvmem_device **nvmem = res;
756 if (WARN_ON(!nvmem || !*nvmem))
759 return *nvmem == data;
762 static void devm_nvmem_device_release(struct device *dev, void *res)
764 nvmem_device_put(*(struct nvmem_device **)res);
768 * devm_nvmem_device_put() - put alredy got nvmem device
770 * @dev: Device that uses the nvmem device.
771 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
772 * that needs to be released.
774 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
778 ret = devres_release(dev, devm_nvmem_device_release,
779 devm_nvmem_device_match, nvmem);
783 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
786 * nvmem_device_put() - put alredy got nvmem device
788 * @nvmem: pointer to nvmem device that needs to be released.
790 void nvmem_device_put(struct nvmem_device *nvmem)
792 __nvmem_device_put(nvmem);
794 EXPORT_SYMBOL_GPL(nvmem_device_put);
797 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
799 * @dev: Device that requests the nvmem device.
800 * @id: name id for the requested nvmem device.
802 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
803 * on success. The nvmem_cell will be freed by the automatically once the
806 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
808 struct nvmem_device **ptr, *nvmem;
810 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
812 return ERR_PTR(-ENOMEM);
814 nvmem = nvmem_device_get(dev, id);
815 if (!IS_ERR(nvmem)) {
817 devres_add(dev, ptr);
824 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
826 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
828 struct nvmem_cell *cell = NULL;
829 struct nvmem_device *nvmem;
831 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
833 return ERR_CAST(nvmem);
838 #if IS_ENABLED(CONFIG_OF)
840 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
842 * @np: Device tree node that uses the nvmem cell.
843 * @name: nvmem cell name from nvmem-cell-names property, or NULL
844 * for the cell at index 0 (the lone cell with no accompanying
845 * nvmem-cell-names property).
847 * Return: Will be an ERR_PTR() on error or a valid pointer
848 * to a struct nvmem_cell. The nvmem_cell will be freed by the
851 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
854 struct device_node *cell_np, *nvmem_np;
855 struct nvmem_cell *cell;
856 struct nvmem_device *nvmem;
861 /* if cell name exists, find index to the name */
863 index = of_property_match_string(np, "nvmem-cell-names", name);
865 cell_np = of_parse_phandle(np, "nvmem-cells", index);
867 return ERR_PTR(-EINVAL);
869 nvmem_np = of_get_next_parent(cell_np);
871 return ERR_PTR(-EINVAL);
873 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
874 of_node_put(nvmem_np);
876 return ERR_CAST(nvmem);
878 addr = of_get_property(cell_np, "reg", &len);
879 if (!addr || (len < 2 * sizeof(u32))) {
880 dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n",
886 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
893 cell->offset = be32_to_cpup(addr++);
894 cell->bytes = be32_to_cpup(addr);
895 cell->name = cell_np->name;
897 addr = of_get_property(cell_np, "bits", &len);
898 if (addr && len == (2 * sizeof(u32))) {
899 cell->bit_offset = be32_to_cpup(addr++);
900 cell->nbits = be32_to_cpup(addr);
904 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
907 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
909 "cell %s unaligned to nvmem stride %d\n",
910 cell->name, nvmem->stride);
915 nvmem_cell_add(cell);
923 __nvmem_device_put(nvmem);
925 return ERR_PTR(rval);
927 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
931 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
933 * @dev: Device that requests the nvmem cell.
934 * @cell_id: nvmem cell name to get.
936 * Return: Will be an ERR_PTR() on error or a valid pointer
937 * to a struct nvmem_cell. The nvmem_cell will be freed by the
940 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
942 struct nvmem_cell *cell;
944 if (dev->of_node) { /* try dt first */
945 cell = of_nvmem_cell_get(dev->of_node, cell_id);
946 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
950 /* NULL cell_id only allowed for device tree; invalid otherwise */
952 return ERR_PTR(-EINVAL);
954 return nvmem_cell_get_from_list(cell_id);
956 EXPORT_SYMBOL_GPL(nvmem_cell_get);
958 static void devm_nvmem_cell_release(struct device *dev, void *res)
960 nvmem_cell_put(*(struct nvmem_cell **)res);
964 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
966 * @dev: Device that requests the nvmem cell.
967 * @id: nvmem cell name id to get.
969 * Return: Will be an ERR_PTR() on error or a valid pointer
970 * to a struct nvmem_cell. The nvmem_cell will be freed by the
971 * automatically once the device is freed.
973 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
975 struct nvmem_cell **ptr, *cell;
977 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
979 return ERR_PTR(-ENOMEM);
981 cell = nvmem_cell_get(dev, id);
984 devres_add(dev, ptr);
991 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
993 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
995 struct nvmem_cell **c = res;
997 if (WARN_ON(!c || !*c))
1004 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
1005 * from devm_nvmem_cell_get.
1007 * @dev: Device that requests the nvmem cell.
1008 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
1010 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
1014 ret = devres_release(dev, devm_nvmem_cell_release,
1015 devm_nvmem_cell_match, cell);
1019 EXPORT_SYMBOL(devm_nvmem_cell_put);
1022 * nvmem_cell_put() - Release previously allocated nvmem cell.
1024 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
1026 void nvmem_cell_put(struct nvmem_cell *cell)
1028 struct nvmem_device *nvmem = cell->nvmem;
1030 __nvmem_device_put(nvmem);
1031 nvmem_cell_drop(cell);
1033 EXPORT_SYMBOL_GPL(nvmem_cell_put);
1035 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
1038 int i, extra, bit_offset = cell->bit_offset;
1043 *b++ >>= bit_offset;
1045 /* setup rest of the bytes if any */
1046 for (i = 1; i < cell->bytes; i++) {
1047 /* Get bits from next byte and shift them towards msb */
1048 *p |= *b << (BITS_PER_BYTE - bit_offset);
1051 *b++ >>= bit_offset;
1054 /* point to the msb */
1055 p += cell->bytes - 1;
1058 /* result fits in less bytes */
1059 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
1060 while (--extra >= 0)
1063 /* clear msb bits if any leftover in the last byte */
1064 if (cell->nbits % BITS_PER_BYTE)
1065 *p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
1068 static int __nvmem_cell_read(struct nvmem_device *nvmem,
1069 struct nvmem_cell *cell,
1070 void *buf, size_t *len)
1074 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
1079 /* shift bits in-place */
1080 if (cell->bit_offset || cell->nbits)
1081 nvmem_shift_read_buffer_in_place(cell, buf);
1090 * nvmem_cell_read() - Read a given nvmem cell
1092 * @cell: nvmem cell to be read.
1093 * @len: pointer to length of cell which will be populated on successful read;
1096 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1097 * buffer should be freed by the consumer with a kfree().
1099 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
1101 struct nvmem_device *nvmem = cell->nvmem;
1106 return ERR_PTR(-EINVAL);
1108 buf = kzalloc(cell->bytes, GFP_KERNEL);
1110 return ERR_PTR(-ENOMEM);
1112 rc = __nvmem_cell_read(nvmem, cell, buf, len);
1120 EXPORT_SYMBOL_GPL(nvmem_cell_read);
1122 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
1125 struct nvmem_device *nvmem = cell->nvmem;
1126 int i, rc, nbits, bit_offset = cell->bit_offset;
1127 u8 v, *p, *buf, *b, pbyte, pbits;
1129 nbits = cell->nbits;
1130 buf = kzalloc(cell->bytes, GFP_KERNEL);
1132 return ERR_PTR(-ENOMEM);
1134 memcpy(buf, _buf, len);
1141 /* setup the first byte with lsb bits from nvmem */
1142 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1145 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1147 /* setup rest of the byte if any */
1148 for (i = 1; i < cell->bytes; i++) {
1149 /* Get last byte bits and shift them towards lsb */
1150 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1158 /* if it's not end on byte boundary */
1159 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1160 /* setup the last byte with msb bits from nvmem */
1161 rc = nvmem_reg_read(nvmem,
1162 cell->offset + cell->bytes - 1, &v, 1);
1165 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1176 * nvmem_cell_write() - Write to a given nvmem cell
1178 * @cell: nvmem cell to be written.
1179 * @buf: Buffer to be written.
1180 * @len: length of buffer to be written to nvmem cell.
1182 * Return: length of bytes written or negative on failure.
1184 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1186 struct nvmem_device *nvmem = cell->nvmem;
1189 if (!nvmem || nvmem->read_only ||
1190 (cell->bit_offset == 0 && len != cell->bytes))
1193 if (cell->bit_offset || cell->nbits) {
1194 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1196 return PTR_ERR(buf);
1199 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1201 /* free the tmp buffer */
1202 if (cell->bit_offset || cell->nbits)
1210 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1213 * nvmem_cell_read_u32() - Read a cell value as an u32
1215 * @dev: Device that requests the nvmem cell.
1216 * @cell_id: Name of nvmem cell to read.
1217 * @val: pointer to output value.
1219 * Return: 0 on success or negative errno.
1221 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1223 struct nvmem_cell *cell;
1227 cell = nvmem_cell_get(dev, cell_id);
1229 return PTR_ERR(cell);
1231 buf = nvmem_cell_read(cell, &len);
1233 nvmem_cell_put(cell);
1234 return PTR_ERR(buf);
1236 if (len != sizeof(*val)) {
1238 nvmem_cell_put(cell);
1241 memcpy(val, buf, sizeof(*val));
1244 nvmem_cell_put(cell);
1247 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1250 * nvmem_device_cell_read() - Read a given nvmem device and cell
1252 * @nvmem: nvmem device to read from.
1253 * @info: nvmem cell info to be read.
1254 * @buf: buffer pointer which will be populated on successful read.
1256 * Return: length of successful bytes read on success and negative
1257 * error code on error.
1259 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1260 struct nvmem_cell_info *info, void *buf)
1262 struct nvmem_cell cell;
1269 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1273 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1279 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1282 * nvmem_device_cell_write() - Write cell to a given nvmem device
1284 * @nvmem: nvmem device to be written to.
1285 * @info: nvmem cell info to be written.
1286 * @buf: buffer to be written to cell.
1288 * Return: length of bytes written or negative error code on failure.
1290 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1291 struct nvmem_cell_info *info, void *buf)
1293 struct nvmem_cell cell;
1299 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1303 return nvmem_cell_write(&cell, buf, cell.bytes);
1305 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1308 * nvmem_device_read() - Read from a given nvmem device
1310 * @nvmem: nvmem device to read from.
1311 * @offset: offset in nvmem device.
1312 * @bytes: number of bytes to read.
1313 * @buf: buffer pointer which will be populated on successful read.
1315 * Return: length of successful bytes read on success and negative
1316 * error code on error.
1318 int nvmem_device_read(struct nvmem_device *nvmem,
1319 unsigned int offset,
1320 size_t bytes, void *buf)
1327 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1334 EXPORT_SYMBOL_GPL(nvmem_device_read);
1337 * nvmem_device_write() - Write cell to a given nvmem device
1339 * @nvmem: nvmem device to be written to.
1340 * @offset: offset in nvmem device.
1341 * @bytes: number of bytes to write.
1342 * @buf: buffer to be written.
1344 * Return: length of bytes written or negative error code on failure.
1346 int nvmem_device_write(struct nvmem_device *nvmem,
1347 unsigned int offset,
1348 size_t bytes, void *buf)
1355 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1363 EXPORT_SYMBOL_GPL(nvmem_device_write);
1365 static int __init nvmem_init(void)
1367 return bus_register(&nvmem_bus_type);
1370 static void __exit nvmem_exit(void)
1372 bus_unregister(&nvmem_bus_type);
1375 subsys_initcall(nvmem_init);
1376 module_exit(nvmem_exit);
1378 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1379 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1380 MODULE_DESCRIPTION("nvmem Driver Core");
1381 MODULE_LICENSE("GPL v2");