1 // SPDX-License-Identifier: GPL-2.0
3 * nvmem framework core.
5 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
6 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
9 #include <linux/device.h>
10 #include <linux/export.h>
12 #include <linux/idr.h>
13 #include <linux/init.h>
14 #include <linux/kref.h>
15 #include <linux/module.h>
16 #include <linux/nvmem-consumer.h>
17 #include <linux/nvmem-provider.h>
19 #include <linux/slab.h>
28 struct device_node *np;
29 struct nvmem_device *nvmem;
30 struct list_head node;
33 static DEFINE_MUTEX(nvmem_mutex);
34 static DEFINE_IDA(nvmem_ida);
36 static DEFINE_MUTEX(nvmem_cell_mutex);
37 static LIST_HEAD(nvmem_cell_tables);
39 static DEFINE_MUTEX(nvmem_lookup_mutex);
40 static LIST_HEAD(nvmem_lookup_list);
42 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
45 static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
46 void *val, size_t bytes)
49 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
54 static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
55 void *val, size_t bytes)
58 return nvmem->reg_write(nvmem->priv, offset, val, bytes);
63 static void nvmem_release(struct device *dev)
65 struct nvmem_device *nvmem = to_nvmem_device(dev);
67 ida_simple_remove(&nvmem_ida, nvmem->id);
71 static const struct device_type nvmem_provider_type = {
72 .release = nvmem_release,
75 static struct bus_type nvmem_bus_type = {
79 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
86 d = bus_find_device_by_of_node(&nvmem_bus_type, nvmem_np);
91 return to_nvmem_device(d);
94 static struct nvmem_device *nvmem_find(const char *name)
98 d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
103 return to_nvmem_device(d);
106 static void nvmem_cell_drop(struct nvmem_cell *cell)
108 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
109 mutex_lock(&nvmem_mutex);
110 list_del(&cell->node);
111 mutex_unlock(&nvmem_mutex);
112 of_node_put(cell->np);
117 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
119 struct nvmem_cell *cell, *p;
121 list_for_each_entry_safe(cell, p, &nvmem->cells, node)
122 nvmem_cell_drop(cell);
125 static void nvmem_cell_add(struct nvmem_cell *cell)
127 mutex_lock(&nvmem_mutex);
128 list_add_tail(&cell->node, &cell->nvmem->cells);
129 mutex_unlock(&nvmem_mutex);
130 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
133 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
134 const struct nvmem_cell_info *info,
135 struct nvmem_cell *cell)
138 cell->offset = info->offset;
139 cell->bytes = info->bytes;
140 cell->name = info->name;
142 cell->bit_offset = info->bit_offset;
143 cell->nbits = info->nbits;
146 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
149 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
151 "cell %s unaligned to nvmem stride %d\n",
152 cell->name, nvmem->stride);
160 * nvmem_add_cells() - Add cell information to an nvmem device
162 * @nvmem: nvmem device to add cells to.
163 * @info: nvmem cell info to add to the device
164 * @ncells: number of cells in info
166 * Return: 0 or negative error code on failure.
168 static int nvmem_add_cells(struct nvmem_device *nvmem,
169 const struct nvmem_cell_info *info,
172 struct nvmem_cell **cells;
175 cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
179 for (i = 0; i < ncells; i++) {
180 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
186 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
192 nvmem_cell_add(cells[i]);
195 /* remove tmp array */
201 nvmem_cell_drop(cells[i]);
209 * nvmem_register_notifier() - Register a notifier block for nvmem events.
211 * @nb: notifier block to be called on nvmem events.
213 * Return: 0 on success, negative error number on failure.
215 int nvmem_register_notifier(struct notifier_block *nb)
217 return blocking_notifier_chain_register(&nvmem_notifier, nb);
219 EXPORT_SYMBOL_GPL(nvmem_register_notifier);
222 * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
224 * @nb: notifier block to be unregistered.
226 * Return: 0 on success, negative error number on failure.
228 int nvmem_unregister_notifier(struct notifier_block *nb)
230 return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
232 EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
234 static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
236 const struct nvmem_cell_info *info;
237 struct nvmem_cell_table *table;
238 struct nvmem_cell *cell;
241 mutex_lock(&nvmem_cell_mutex);
242 list_for_each_entry(table, &nvmem_cell_tables, node) {
243 if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
244 for (i = 0; i < table->ncells; i++) {
245 info = &table->cells[i];
247 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
253 rval = nvmem_cell_info_to_nvmem_cell(nvmem,
261 nvmem_cell_add(cell);
267 mutex_unlock(&nvmem_cell_mutex);
271 static struct nvmem_cell *
272 nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
274 struct nvmem_cell *iter, *cell = NULL;
276 mutex_lock(&nvmem_mutex);
277 list_for_each_entry(iter, &nvmem->cells, node) {
278 if (strcmp(cell_id, iter->name) == 0) {
283 mutex_unlock(&nvmem_mutex);
288 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
290 struct device_node *parent, *child;
291 struct device *dev = &nvmem->dev;
292 struct nvmem_cell *cell;
296 parent = dev->of_node;
298 for_each_child_of_node(parent, child) {
299 addr = of_get_property(child, "reg", &len);
300 if (!addr || (len < 2 * sizeof(u32))) {
301 dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
305 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
310 cell->np = of_node_get(child);
311 cell->offset = be32_to_cpup(addr++);
312 cell->bytes = be32_to_cpup(addr);
313 cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
315 addr = of_get_property(child, "bits", &len);
316 if (addr && len == (2 * sizeof(u32))) {
317 cell->bit_offset = be32_to_cpup(addr++);
318 cell->nbits = be32_to_cpup(addr);
322 cell->bytes = DIV_ROUND_UP(
323 cell->nbits + cell->bit_offset,
326 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
327 dev_err(dev, "cell %s unaligned to nvmem stride %d\n",
328 cell->name, nvmem->stride);
329 /* Cells already added will be freed later. */
335 nvmem_cell_add(cell);
342 * nvmem_register() - Register a nvmem device for given nvmem_config.
343 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
345 * @config: nvmem device configuration with which nvmem device is created.
347 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
351 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
353 struct nvmem_device *nvmem;
357 return ERR_PTR(-EINVAL);
359 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
361 return ERR_PTR(-ENOMEM);
363 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
366 return ERR_PTR(rval);
369 kref_init(&nvmem->refcnt);
370 INIT_LIST_HEAD(&nvmem->cells);
373 nvmem->owner = config->owner;
374 if (!nvmem->owner && config->dev->driver)
375 nvmem->owner = config->dev->driver->owner;
376 nvmem->stride = config->stride ?: 1;
377 nvmem->word_size = config->word_size ?: 1;
378 nvmem->size = config->size;
379 nvmem->dev.type = &nvmem_provider_type;
380 nvmem->dev.bus = &nvmem_bus_type;
381 nvmem->dev.parent = config->dev;
382 nvmem->priv = config->priv;
383 nvmem->type = config->type;
384 nvmem->reg_read = config->reg_read;
385 nvmem->reg_write = config->reg_write;
386 if (!config->no_of_node)
387 nvmem->dev.of_node = config->dev->of_node;
389 if (config->id == -1 && config->name) {
390 dev_set_name(&nvmem->dev, "%s", config->name);
392 dev_set_name(&nvmem->dev, "%s%d",
393 config->name ? : "nvmem",
394 config->name ? config->id : nvmem->id);
397 nvmem->read_only = device_property_present(config->dev, "read-only") ||
398 config->read_only || !nvmem->reg_write;
400 nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config);
402 device_initialize(&nvmem->dev);
404 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
406 rval = device_add(&nvmem->dev);
410 if (config->compat) {
411 rval = nvmem_sysfs_setup_compat(nvmem, config);
417 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
419 goto err_teardown_compat;
422 rval = nvmem_add_cells_from_table(nvmem);
424 goto err_remove_cells;
426 rval = nvmem_add_cells_from_of(nvmem);
428 goto err_remove_cells;
430 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
435 nvmem_device_remove_all_cells(nvmem);
438 nvmem_sysfs_remove_compat(nvmem, config);
440 device_del(&nvmem->dev);
442 put_device(&nvmem->dev);
444 return ERR_PTR(rval);
446 EXPORT_SYMBOL_GPL(nvmem_register);
448 static void nvmem_device_release(struct kref *kref)
450 struct nvmem_device *nvmem;
452 nvmem = container_of(kref, struct nvmem_device, refcnt);
454 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
456 if (nvmem->flags & FLAG_COMPAT)
457 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
459 nvmem_device_remove_all_cells(nvmem);
460 device_del(&nvmem->dev);
461 put_device(&nvmem->dev);
465 * nvmem_unregister() - Unregister previously registered nvmem device
467 * @nvmem: Pointer to previously registered nvmem device.
469 void nvmem_unregister(struct nvmem_device *nvmem)
471 kref_put(&nvmem->refcnt, nvmem_device_release);
473 EXPORT_SYMBOL_GPL(nvmem_unregister);
475 static void devm_nvmem_release(struct device *dev, void *res)
477 nvmem_unregister(*(struct nvmem_device **)res);
481 * devm_nvmem_register() - Register a managed nvmem device for given
483 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
485 * @dev: Device that uses the nvmem device.
486 * @config: nvmem device configuration with which nvmem device is created.
488 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
491 struct nvmem_device *devm_nvmem_register(struct device *dev,
492 const struct nvmem_config *config)
494 struct nvmem_device **ptr, *nvmem;
496 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
498 return ERR_PTR(-ENOMEM);
500 nvmem = nvmem_register(config);
502 if (!IS_ERR(nvmem)) {
504 devres_add(dev, ptr);
511 EXPORT_SYMBOL_GPL(devm_nvmem_register);
513 static int devm_nvmem_match(struct device *dev, void *res, void *data)
515 struct nvmem_device **r = res;
521 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
524 * @dev: Device that uses the nvmem device.
525 * @nvmem: Pointer to previously registered nvmem device.
527 * Return: Will be an negative on error or a zero on success.
529 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
531 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
533 EXPORT_SYMBOL(devm_nvmem_unregister);
535 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
536 const char *nvmem_name)
538 struct nvmem_device *nvmem = NULL;
540 mutex_lock(&nvmem_mutex);
541 nvmem = np ? of_nvmem_find(np) : nvmem_find(nvmem_name);
542 mutex_unlock(&nvmem_mutex);
544 return ERR_PTR(-EPROBE_DEFER);
546 if (!try_module_get(nvmem->owner)) {
548 "could not increase module refcount for cell %s\n",
549 nvmem_dev_name(nvmem));
551 put_device(&nvmem->dev);
552 return ERR_PTR(-EINVAL);
555 kref_get(&nvmem->refcnt);
560 static void __nvmem_device_put(struct nvmem_device *nvmem)
562 put_device(&nvmem->dev);
563 module_put(nvmem->owner);
564 kref_put(&nvmem->refcnt, nvmem_device_release);
567 #if IS_ENABLED(CONFIG_OF)
569 * of_nvmem_device_get() - Get nvmem device from a given id
571 * @np: Device tree node that uses the nvmem device.
572 * @id: nvmem name from nvmem-names property.
574 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
577 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
580 struct device_node *nvmem_np;
584 index = of_property_match_string(np, "nvmem-names", id);
586 nvmem_np = of_parse_phandle(np, "nvmem", index);
588 return ERR_PTR(-ENOENT);
590 return __nvmem_device_get(nvmem_np, NULL);
592 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
596 * nvmem_device_get() - Get nvmem device from a given id
598 * @dev: Device that uses the nvmem device.
599 * @dev_name: name of the requested nvmem device.
601 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
604 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
606 if (dev->of_node) { /* try dt first */
607 struct nvmem_device *nvmem;
609 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
611 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
616 return __nvmem_device_get(NULL, dev_name);
618 EXPORT_SYMBOL_GPL(nvmem_device_get);
620 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
622 struct nvmem_device **nvmem = res;
624 if (WARN_ON(!nvmem || !*nvmem))
627 return *nvmem == data;
630 static void devm_nvmem_device_release(struct device *dev, void *res)
632 nvmem_device_put(*(struct nvmem_device **)res);
636 * devm_nvmem_device_put() - put alredy got nvmem device
638 * @dev: Device that uses the nvmem device.
639 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
640 * that needs to be released.
642 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
646 ret = devres_release(dev, devm_nvmem_device_release,
647 devm_nvmem_device_match, nvmem);
651 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
654 * nvmem_device_put() - put alredy got nvmem device
656 * @nvmem: pointer to nvmem device that needs to be released.
658 void nvmem_device_put(struct nvmem_device *nvmem)
660 __nvmem_device_put(nvmem);
662 EXPORT_SYMBOL_GPL(nvmem_device_put);
665 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
667 * @dev: Device that requests the nvmem device.
668 * @id: name id for the requested nvmem device.
670 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
671 * on success. The nvmem_cell will be freed by the automatically once the
674 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
676 struct nvmem_device **ptr, *nvmem;
678 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
680 return ERR_PTR(-ENOMEM);
682 nvmem = nvmem_device_get(dev, id);
683 if (!IS_ERR(nvmem)) {
685 devres_add(dev, ptr);
692 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
694 static struct nvmem_cell *
695 nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
697 struct nvmem_cell *cell = ERR_PTR(-ENOENT);
698 struct nvmem_cell_lookup *lookup;
699 struct nvmem_device *nvmem;
703 return ERR_PTR(-EINVAL);
705 dev_id = dev_name(dev);
707 mutex_lock(&nvmem_lookup_mutex);
709 list_for_each_entry(lookup, &nvmem_lookup_list, node) {
710 if ((strcmp(lookup->dev_id, dev_id) == 0) &&
711 (strcmp(lookup->con_id, con_id) == 0)) {
712 /* This is the right entry. */
713 nvmem = __nvmem_device_get(NULL, lookup->nvmem_name);
715 /* Provider may not be registered yet. */
716 cell = ERR_CAST(nvmem);
720 cell = nvmem_find_cell_by_name(nvmem,
723 __nvmem_device_put(nvmem);
724 cell = ERR_PTR(-ENOENT);
730 mutex_unlock(&nvmem_lookup_mutex);
734 #if IS_ENABLED(CONFIG_OF)
735 static struct nvmem_cell *
736 nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
738 struct nvmem_cell *iter, *cell = NULL;
740 mutex_lock(&nvmem_mutex);
741 list_for_each_entry(iter, &nvmem->cells, node) {
742 if (np == iter->np) {
747 mutex_unlock(&nvmem_mutex);
753 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
755 * @np: Device tree node that uses the nvmem cell.
756 * @id: nvmem cell name from nvmem-cell-names property, or NULL
757 * for the cell at index 0 (the lone cell with no accompanying
758 * nvmem-cell-names property).
760 * Return: Will be an ERR_PTR() on error or a valid pointer
761 * to a struct nvmem_cell. The nvmem_cell will be freed by the
764 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
766 struct device_node *cell_np, *nvmem_np;
767 struct nvmem_device *nvmem;
768 struct nvmem_cell *cell;
771 /* if cell name exists, find index to the name */
773 index = of_property_match_string(np, "nvmem-cell-names", id);
775 cell_np = of_parse_phandle(np, "nvmem-cells", index);
777 return ERR_PTR(-ENOENT);
779 nvmem_np = of_get_next_parent(cell_np);
781 return ERR_PTR(-EINVAL);
783 nvmem = __nvmem_device_get(nvmem_np, NULL);
784 of_node_put(nvmem_np);
786 return ERR_CAST(nvmem);
788 cell = nvmem_find_cell_by_node(nvmem, cell_np);
790 __nvmem_device_put(nvmem);
791 return ERR_PTR(-ENOENT);
796 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
800 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
802 * @dev: Device that requests the nvmem cell.
803 * @id: nvmem cell name to get (this corresponds with the name from the
804 * nvmem-cell-names property for DT systems and with the con_id from
805 * the lookup entry for non-DT systems).
807 * Return: Will be an ERR_PTR() on error or a valid pointer
808 * to a struct nvmem_cell. The nvmem_cell will be freed by the
811 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
813 struct nvmem_cell *cell;
815 if (dev->of_node) { /* try dt first */
816 cell = of_nvmem_cell_get(dev->of_node, id);
817 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
821 /* NULL cell id only allowed for device tree; invalid otherwise */
823 return ERR_PTR(-EINVAL);
825 return nvmem_cell_get_from_lookup(dev, id);
827 EXPORT_SYMBOL_GPL(nvmem_cell_get);
829 static void devm_nvmem_cell_release(struct device *dev, void *res)
831 nvmem_cell_put(*(struct nvmem_cell **)res);
835 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
837 * @dev: Device that requests the nvmem cell.
838 * @id: nvmem cell name id to get.
840 * Return: Will be an ERR_PTR() on error or a valid pointer
841 * to a struct nvmem_cell. The nvmem_cell will be freed by the
842 * automatically once the device is freed.
844 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
846 struct nvmem_cell **ptr, *cell;
848 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
850 return ERR_PTR(-ENOMEM);
852 cell = nvmem_cell_get(dev, id);
855 devres_add(dev, ptr);
862 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
864 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
866 struct nvmem_cell **c = res;
868 if (WARN_ON(!c || !*c))
875 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
876 * from devm_nvmem_cell_get.
878 * @dev: Device that requests the nvmem cell.
879 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
881 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
885 ret = devres_release(dev, devm_nvmem_cell_release,
886 devm_nvmem_cell_match, cell);
890 EXPORT_SYMBOL(devm_nvmem_cell_put);
893 * nvmem_cell_put() - Release previously allocated nvmem cell.
895 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
897 void nvmem_cell_put(struct nvmem_cell *cell)
899 struct nvmem_device *nvmem = cell->nvmem;
901 __nvmem_device_put(nvmem);
903 EXPORT_SYMBOL_GPL(nvmem_cell_put);
905 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
908 int i, extra, bit_offset = cell->bit_offset;
915 /* setup rest of the bytes if any */
916 for (i = 1; i < cell->bytes; i++) {
917 /* Get bits from next byte and shift them towards msb */
918 *p |= *b << (BITS_PER_BYTE - bit_offset);
924 /* point to the msb */
925 p += cell->bytes - 1;
928 /* result fits in less bytes */
929 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
933 /* clear msb bits if any leftover in the last byte */
934 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
937 static int __nvmem_cell_read(struct nvmem_device *nvmem,
938 struct nvmem_cell *cell,
939 void *buf, size_t *len)
943 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
948 /* shift bits in-place */
949 if (cell->bit_offset || cell->nbits)
950 nvmem_shift_read_buffer_in_place(cell, buf);
959 * nvmem_cell_read() - Read a given nvmem cell
961 * @cell: nvmem cell to be read.
962 * @len: pointer to length of cell which will be populated on successful read;
965 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
966 * buffer should be freed by the consumer with a kfree().
968 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
970 struct nvmem_device *nvmem = cell->nvmem;
975 return ERR_PTR(-EINVAL);
977 buf = kzalloc(cell->bytes, GFP_KERNEL);
979 return ERR_PTR(-ENOMEM);
981 rc = __nvmem_cell_read(nvmem, cell, buf, len);
989 EXPORT_SYMBOL_GPL(nvmem_cell_read);
991 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
994 struct nvmem_device *nvmem = cell->nvmem;
995 int i, rc, nbits, bit_offset = cell->bit_offset;
996 u8 v, *p, *buf, *b, pbyte, pbits;
999 buf = kzalloc(cell->bytes, GFP_KERNEL);
1001 return ERR_PTR(-ENOMEM);
1003 memcpy(buf, _buf, len);
1010 /* setup the first byte with lsb bits from nvmem */
1011 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1014 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1016 /* setup rest of the byte if any */
1017 for (i = 1; i < cell->bytes; i++) {
1018 /* Get last byte bits and shift them towards lsb */
1019 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1027 /* if it's not end on byte boundary */
1028 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1029 /* setup the last byte with msb bits from nvmem */
1030 rc = nvmem_reg_read(nvmem,
1031 cell->offset + cell->bytes - 1, &v, 1);
1034 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1045 * nvmem_cell_write() - Write to a given nvmem cell
1047 * @cell: nvmem cell to be written.
1048 * @buf: Buffer to be written.
1049 * @len: length of buffer to be written to nvmem cell.
1051 * Return: length of bytes written or negative on failure.
1053 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1055 struct nvmem_device *nvmem = cell->nvmem;
1058 if (!nvmem || nvmem->read_only ||
1059 (cell->bit_offset == 0 && len != cell->bytes))
1062 if (cell->bit_offset || cell->nbits) {
1063 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1065 return PTR_ERR(buf);
1068 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1070 /* free the tmp buffer */
1071 if (cell->bit_offset || cell->nbits)
1079 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1082 * nvmem_cell_read_u16() - Read a cell value as an u16
1084 * @dev: Device that requests the nvmem cell.
1085 * @cell_id: Name of nvmem cell to read.
1086 * @val: pointer to output value.
1088 * Return: 0 on success or negative errno.
1090 int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1092 struct nvmem_cell *cell;
1096 cell = nvmem_cell_get(dev, cell_id);
1098 return PTR_ERR(cell);
1100 buf = nvmem_cell_read(cell, &len);
1102 nvmem_cell_put(cell);
1103 return PTR_ERR(buf);
1105 if (len != sizeof(*val)) {
1107 nvmem_cell_put(cell);
1110 memcpy(val, buf, sizeof(*val));
1112 nvmem_cell_put(cell);
1116 EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1119 * nvmem_cell_read_u32() - Read a cell value as an u32
1121 * @dev: Device that requests the nvmem cell.
1122 * @cell_id: Name of nvmem cell to read.
1123 * @val: pointer to output value.
1125 * Return: 0 on success or negative errno.
1127 int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1129 struct nvmem_cell *cell;
1133 cell = nvmem_cell_get(dev, cell_id);
1135 return PTR_ERR(cell);
1137 buf = nvmem_cell_read(cell, &len);
1139 nvmem_cell_put(cell);
1140 return PTR_ERR(buf);
1142 if (len != sizeof(*val)) {
1144 nvmem_cell_put(cell);
1147 memcpy(val, buf, sizeof(*val));
1150 nvmem_cell_put(cell);
1153 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1156 * nvmem_device_cell_read() - Read a given nvmem device and cell
1158 * @nvmem: nvmem device to read from.
1159 * @info: nvmem cell info to be read.
1160 * @buf: buffer pointer which will be populated on successful read.
1162 * Return: length of successful bytes read on success and negative
1163 * error code on error.
1165 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1166 struct nvmem_cell_info *info, void *buf)
1168 struct nvmem_cell cell;
1175 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1179 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1185 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1188 * nvmem_device_cell_write() - Write cell to a given nvmem device
1190 * @nvmem: nvmem device to be written to.
1191 * @info: nvmem cell info to be written.
1192 * @buf: buffer to be written to cell.
1194 * Return: length of bytes written or negative error code on failure.
1196 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1197 struct nvmem_cell_info *info, void *buf)
1199 struct nvmem_cell cell;
1205 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1209 return nvmem_cell_write(&cell, buf, cell.bytes);
1211 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1214 * nvmem_device_read() - Read from a given nvmem device
1216 * @nvmem: nvmem device to read from.
1217 * @offset: offset in nvmem device.
1218 * @bytes: number of bytes to read.
1219 * @buf: buffer pointer which will be populated on successful read.
1221 * Return: length of successful bytes read on success and negative
1222 * error code on error.
1224 int nvmem_device_read(struct nvmem_device *nvmem,
1225 unsigned int offset,
1226 size_t bytes, void *buf)
1233 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1240 EXPORT_SYMBOL_GPL(nvmem_device_read);
1243 * nvmem_device_write() - Write cell to a given nvmem device
1245 * @nvmem: nvmem device to be written to.
1246 * @offset: offset in nvmem device.
1247 * @bytes: number of bytes to write.
1248 * @buf: buffer to be written.
1250 * Return: length of bytes written or negative error code on failure.
1252 int nvmem_device_write(struct nvmem_device *nvmem,
1253 unsigned int offset,
1254 size_t bytes, void *buf)
1261 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1269 EXPORT_SYMBOL_GPL(nvmem_device_write);
1272 * nvmem_add_cell_table() - register a table of cell info entries
1274 * @table: table of cell info entries
1276 void nvmem_add_cell_table(struct nvmem_cell_table *table)
1278 mutex_lock(&nvmem_cell_mutex);
1279 list_add_tail(&table->node, &nvmem_cell_tables);
1280 mutex_unlock(&nvmem_cell_mutex);
1282 EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
1285 * nvmem_del_cell_table() - remove a previously registered cell info table
1287 * @table: table of cell info entries
1289 void nvmem_del_cell_table(struct nvmem_cell_table *table)
1291 mutex_lock(&nvmem_cell_mutex);
1292 list_del(&table->node);
1293 mutex_unlock(&nvmem_cell_mutex);
1295 EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
1298 * nvmem_add_cell_lookups() - register a list of cell lookup entries
1300 * @entries: array of cell lookup entries
1301 * @nentries: number of cell lookup entries in the array
1303 void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1307 mutex_lock(&nvmem_lookup_mutex);
1308 for (i = 0; i < nentries; i++)
1309 list_add_tail(&entries[i].node, &nvmem_lookup_list);
1310 mutex_unlock(&nvmem_lookup_mutex);
1312 EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
1315 * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
1318 * @entries: array of cell lookup entries
1319 * @nentries: number of cell lookup entries in the array
1321 void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1325 mutex_lock(&nvmem_lookup_mutex);
1326 for (i = 0; i < nentries; i++)
1327 list_del(&entries[i].node);
1328 mutex_unlock(&nvmem_lookup_mutex);
1330 EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
1333 * nvmem_dev_name() - Get the name of a given nvmem device.
1335 * @nvmem: nvmem device.
1337 * Return: name of the nvmem device.
1339 const char *nvmem_dev_name(struct nvmem_device *nvmem)
1341 return dev_name(&nvmem->dev);
1343 EXPORT_SYMBOL_GPL(nvmem_dev_name);
1345 static int __init nvmem_init(void)
1347 return bus_register(&nvmem_bus_type);
1350 static void __exit nvmem_exit(void)
1352 bus_unregister(&nvmem_bus_type);
1355 subsys_initcall(nvmem_init);
1356 module_exit(nvmem_exit);
1358 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1359 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1360 MODULE_DESCRIPTION("nvmem Driver Core");
1361 MODULE_LICENSE("GPL v2");