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 nvmem
->eeprom
= bin_attr_ro_root_nvmem
;
413 nvmem
->eeprom
= bin_attr_rw_root_nvmem
;
414 nvmem
->eeprom
.attr
.name
= "eeprom";
415 nvmem
->eeprom
.size
= nvmem
->size
;
416 #ifdef CONFIG_DEBUG_LOCK_ALLOC
417 nvmem
->eeprom
.attr
.key
= &eeprom_lock_key
;
419 nvmem
->eeprom
.private = &nvmem
->dev
;
420 nvmem
->base_dev
= config
->base_dev
;
422 rval
= device_create_bin_file(nvmem
->base_dev
, &nvmem
->eeprom
);
425 "Failed to create eeprom binary file %d\n", rval
);
429 nvmem
->flags
|= FLAG_COMPAT
;
435 * nvmem_register() - Register a nvmem device for given nvmem_config.
436 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
438 * @config: nvmem device configuration with which nvmem device is created.
440 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
444 struct nvmem_device
*nvmem_register(const struct nvmem_config
*config
)
446 struct nvmem_device
*nvmem
;
447 struct device_node
*np
;
451 return ERR_PTR(-EINVAL
);
453 nvmem
= kzalloc(sizeof(*nvmem
), GFP_KERNEL
);
455 return ERR_PTR(-ENOMEM
);
457 rval
= ida_simple_get(&nvmem_ida
, 0, 0, GFP_KERNEL
);
460 return ERR_PTR(rval
);
464 nvmem
->owner
= config
->owner
;
465 nvmem
->stride
= config
->stride
;
466 nvmem
->word_size
= config
->word_size
;
467 nvmem
->size
= config
->size
;
468 nvmem
->dev
.type
= &nvmem_provider_type
;
469 nvmem
->dev
.bus
= &nvmem_bus_type
;
470 nvmem
->dev
.parent
= config
->dev
;
471 nvmem
->priv
= config
->priv
;
472 nvmem
->reg_read
= config
->reg_read
;
473 nvmem
->reg_write
= config
->reg_write
;
474 np
= config
->dev
->of_node
;
475 nvmem
->dev
.of_node
= np
;
476 dev_set_name(&nvmem
->dev
, "%s%d",
477 config
->name
? : "nvmem",
478 config
->name
? config
->id
: nvmem
->id
);
480 nvmem
->read_only
= of_property_read_bool(np
, "read-only") |
483 if (config
->root_only
)
484 nvmem
->dev
.groups
= nvmem
->read_only
?
485 nvmem_ro_root_dev_groups
:
486 nvmem_rw_root_dev_groups
;
488 nvmem
->dev
.groups
= nvmem
->read_only
?
489 nvmem_ro_dev_groups
:
492 device_initialize(&nvmem
->dev
);
494 dev_dbg(&nvmem
->dev
, "Registering nvmem device %s\n", config
->name
);
496 rval
= device_add(&nvmem
->dev
);
500 if (config
->compat
) {
501 rval
= nvmem_setup_compat(nvmem
, config
);
507 nvmem_add_cells(nvmem
, config
);
512 device_del(&nvmem
->dev
);
514 put_device(&nvmem
->dev
);
516 return ERR_PTR(rval
);
518 EXPORT_SYMBOL_GPL(nvmem_register
);
521 * nvmem_unregister() - Unregister previously registered nvmem device
523 * @nvmem: Pointer to previously registered nvmem device.
525 * Return: Will be an negative on error or a zero on success.
527 int nvmem_unregister(struct nvmem_device
*nvmem
)
529 mutex_lock(&nvmem_mutex
);
531 mutex_unlock(&nvmem_mutex
);
534 mutex_unlock(&nvmem_mutex
);
536 if (nvmem
->flags
& FLAG_COMPAT
)
537 device_remove_bin_file(nvmem
->base_dev
, &nvmem
->eeprom
);
539 nvmem_device_remove_all_cells(nvmem
);
540 device_del(&nvmem
->dev
);
541 put_device(&nvmem
->dev
);
545 EXPORT_SYMBOL_GPL(nvmem_unregister
);
547 static struct nvmem_device
*__nvmem_device_get(struct device_node
*np
,
548 struct nvmem_cell
**cellp
,
551 struct nvmem_device
*nvmem
= NULL
;
553 mutex_lock(&nvmem_mutex
);
556 nvmem
= of_nvmem_find(np
);
558 mutex_unlock(&nvmem_mutex
);
559 return ERR_PTR(-EPROBE_DEFER
);
562 struct nvmem_cell
*cell
= nvmem_find_cell(cell_id
);
570 mutex_unlock(&nvmem_mutex
);
571 return ERR_PTR(-ENOENT
);
576 mutex_unlock(&nvmem_mutex
);
578 if (!try_module_get(nvmem
->owner
)) {
580 "could not increase module refcount for cell %s\n",
583 mutex_lock(&nvmem_mutex
);
585 mutex_unlock(&nvmem_mutex
);
587 return ERR_PTR(-EINVAL
);
593 static void __nvmem_device_put(struct nvmem_device
*nvmem
)
595 module_put(nvmem
->owner
);
596 mutex_lock(&nvmem_mutex
);
598 mutex_unlock(&nvmem_mutex
);
601 static int nvmem_match(struct device
*dev
, void *data
)
603 return !strcmp(dev_name(dev
), data
);
606 static struct nvmem_device
*nvmem_find(const char *name
)
610 d
= bus_find_device(&nvmem_bus_type
, NULL
, (void *)name
, nvmem_match
);
615 return to_nvmem_device(d
);
618 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
620 * of_nvmem_device_get() - Get nvmem device from a given id
622 * @np: Device tree node that uses the nvmem device.
623 * @id: nvmem name from nvmem-names property.
625 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
628 struct nvmem_device
*of_nvmem_device_get(struct device_node
*np
, const char *id
)
631 struct device_node
*nvmem_np
;
634 index
= of_property_match_string(np
, "nvmem-names", id
);
636 nvmem_np
= of_parse_phandle(np
, "nvmem", index
);
638 return ERR_PTR(-EINVAL
);
640 return __nvmem_device_get(nvmem_np
, NULL
, NULL
);
642 EXPORT_SYMBOL_GPL(of_nvmem_device_get
);
646 * nvmem_device_get() - Get nvmem device from a given id
648 * @dev: Device that uses the nvmem device.
649 * @dev_name: name of the requested nvmem device.
651 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
654 struct nvmem_device
*nvmem_device_get(struct device
*dev
, const char *dev_name
)
656 if (dev
->of_node
) { /* try dt first */
657 struct nvmem_device
*nvmem
;
659 nvmem
= of_nvmem_device_get(dev
->of_node
, dev_name
);
661 if (!IS_ERR(nvmem
) || PTR_ERR(nvmem
) == -EPROBE_DEFER
)
666 return nvmem_find(dev_name
);
668 EXPORT_SYMBOL_GPL(nvmem_device_get
);
670 static int devm_nvmem_device_match(struct device
*dev
, void *res
, void *data
)
672 struct nvmem_device
**nvmem
= res
;
674 if (WARN_ON(!nvmem
|| !*nvmem
))
677 return *nvmem
== data
;
680 static void devm_nvmem_device_release(struct device
*dev
, void *res
)
682 nvmem_device_put(*(struct nvmem_device
**)res
);
686 * devm_nvmem_device_put() - put alredy got nvmem device
688 * @dev: Device that uses the nvmem device.
689 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
690 * that needs to be released.
692 void devm_nvmem_device_put(struct device
*dev
, struct nvmem_device
*nvmem
)
696 ret
= devres_release(dev
, devm_nvmem_device_release
,
697 devm_nvmem_device_match
, nvmem
);
701 EXPORT_SYMBOL_GPL(devm_nvmem_device_put
);
704 * nvmem_device_put() - put alredy got nvmem device
706 * @nvmem: pointer to nvmem device that needs to be released.
708 void nvmem_device_put(struct nvmem_device
*nvmem
)
710 __nvmem_device_put(nvmem
);
712 EXPORT_SYMBOL_GPL(nvmem_device_put
);
715 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
717 * @dev: Device that requests the nvmem device.
718 * @id: name id for the requested nvmem device.
720 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
721 * on success. The nvmem_cell will be freed by the automatically once the
724 struct nvmem_device
*devm_nvmem_device_get(struct device
*dev
, const char *id
)
726 struct nvmem_device
**ptr
, *nvmem
;
728 ptr
= devres_alloc(devm_nvmem_device_release
, sizeof(*ptr
), GFP_KERNEL
);
730 return ERR_PTR(-ENOMEM
);
732 nvmem
= nvmem_device_get(dev
, id
);
733 if (!IS_ERR(nvmem
)) {
735 devres_add(dev
, ptr
);
742 EXPORT_SYMBOL_GPL(devm_nvmem_device_get
);
744 static struct nvmem_cell
*nvmem_cell_get_from_list(const char *cell_id
)
746 struct nvmem_cell
*cell
= NULL
;
747 struct nvmem_device
*nvmem
;
749 nvmem
= __nvmem_device_get(NULL
, &cell
, cell_id
);
751 return ERR_CAST(nvmem
);
756 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
758 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
760 * @np: Device tree node that uses the nvmem cell.
761 * @name: nvmem cell name from nvmem-cell-names property, or NULL
762 * for the cell at index 0 (the lone cell with no accompanying
763 * nvmem-cell-names property).
765 * Return: Will be an ERR_PTR() on error or a valid pointer
766 * to a struct nvmem_cell. The nvmem_cell will be freed by the
769 struct nvmem_cell
*of_nvmem_cell_get(struct device_node
*np
,
772 struct device_node
*cell_np
, *nvmem_np
;
773 struct nvmem_cell
*cell
;
774 struct nvmem_device
*nvmem
;
779 /* if cell name exists, find index to the name */
781 index
= of_property_match_string(np
, "nvmem-cell-names", name
);
783 cell_np
= of_parse_phandle(np
, "nvmem-cells", index
);
785 return ERR_PTR(-EINVAL
);
787 nvmem_np
= of_get_next_parent(cell_np
);
789 return ERR_PTR(-EINVAL
);
791 nvmem
= __nvmem_device_get(nvmem_np
, NULL
, NULL
);
792 of_node_put(nvmem_np
);
794 return ERR_CAST(nvmem
);
796 addr
= of_get_property(cell_np
, "reg", &len
);
797 if (!addr
|| (len
< 2 * sizeof(u32
))) {
798 dev_err(&nvmem
->dev
, "nvmem: invalid reg on %pOF\n",
804 cell
= kzalloc(sizeof(*cell
), GFP_KERNEL
);
811 cell
->offset
= be32_to_cpup(addr
++);
812 cell
->bytes
= be32_to_cpup(addr
);
813 cell
->name
= cell_np
->name
;
815 addr
= of_get_property(cell_np
, "bits", &len
);
816 if (addr
&& len
== (2 * sizeof(u32
))) {
817 cell
->bit_offset
= be32_to_cpup(addr
++);
818 cell
->nbits
= be32_to_cpup(addr
);
822 cell
->bytes
= DIV_ROUND_UP(cell
->nbits
+ cell
->bit_offset
,
825 if (!IS_ALIGNED(cell
->offset
, nvmem
->stride
)) {
827 "cell %s unaligned to nvmem stride %d\n",
828 cell
->name
, nvmem
->stride
);
833 nvmem_cell_add(cell
);
841 __nvmem_device_put(nvmem
);
843 return ERR_PTR(rval
);
845 EXPORT_SYMBOL_GPL(of_nvmem_cell_get
);
849 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
851 * @dev: Device that requests the nvmem cell.
852 * @cell_id: nvmem cell name to get.
854 * Return: Will be an ERR_PTR() on error or a valid pointer
855 * to a struct nvmem_cell. The nvmem_cell will be freed by the
858 struct nvmem_cell
*nvmem_cell_get(struct device
*dev
, const char *cell_id
)
860 struct nvmem_cell
*cell
;
862 if (dev
->of_node
) { /* try dt first */
863 cell
= of_nvmem_cell_get(dev
->of_node
, cell_id
);
864 if (!IS_ERR(cell
) || PTR_ERR(cell
) == -EPROBE_DEFER
)
868 /* NULL cell_id only allowed for device tree; invalid otherwise */
870 return ERR_PTR(-EINVAL
);
872 return nvmem_cell_get_from_list(cell_id
);
874 EXPORT_SYMBOL_GPL(nvmem_cell_get
);
876 static void devm_nvmem_cell_release(struct device
*dev
, void *res
)
878 nvmem_cell_put(*(struct nvmem_cell
**)res
);
882 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
884 * @dev: Device that requests the nvmem cell.
885 * @id: nvmem cell name id to get.
887 * Return: Will be an ERR_PTR() on error or a valid pointer
888 * to a struct nvmem_cell. The nvmem_cell will be freed by the
889 * automatically once the device is freed.
891 struct nvmem_cell
*devm_nvmem_cell_get(struct device
*dev
, const char *id
)
893 struct nvmem_cell
**ptr
, *cell
;
895 ptr
= devres_alloc(devm_nvmem_cell_release
, sizeof(*ptr
), GFP_KERNEL
);
897 return ERR_PTR(-ENOMEM
);
899 cell
= nvmem_cell_get(dev
, id
);
902 devres_add(dev
, ptr
);
909 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get
);
911 static int devm_nvmem_cell_match(struct device
*dev
, void *res
, void *data
)
913 struct nvmem_cell
**c
= res
;
915 if (WARN_ON(!c
|| !*c
))
922 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
923 * from devm_nvmem_cell_get.
925 * @dev: Device that requests the nvmem cell.
926 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
928 void devm_nvmem_cell_put(struct device
*dev
, struct nvmem_cell
*cell
)
932 ret
= devres_release(dev
, devm_nvmem_cell_release
,
933 devm_nvmem_cell_match
, cell
);
937 EXPORT_SYMBOL(devm_nvmem_cell_put
);
940 * nvmem_cell_put() - Release previously allocated nvmem cell.
942 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
944 void nvmem_cell_put(struct nvmem_cell
*cell
)
946 struct nvmem_device
*nvmem
= cell
->nvmem
;
948 __nvmem_device_put(nvmem
);
949 nvmem_cell_drop(cell
);
951 EXPORT_SYMBOL_GPL(nvmem_cell_put
);
953 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell
*cell
,
957 int i
, bit_offset
= cell
->bit_offset
;
964 /* setup rest of the bytes if any */
965 for (i
= 1; i
< cell
->bytes
; i
++) {
966 /* Get bits from next byte and shift them towards msb */
967 *p
|= *b
<< (BITS_PER_BYTE
- bit_offset
);
973 /* result fits in less bytes */
974 if (cell
->bytes
!= DIV_ROUND_UP(cell
->nbits
, BITS_PER_BYTE
))
977 /* clear msb bits if any leftover in the last byte */
978 *p
&= GENMASK((cell
->nbits
%BITS_PER_BYTE
) - 1, 0);
981 static int __nvmem_cell_read(struct nvmem_device
*nvmem
,
982 struct nvmem_cell
*cell
,
983 void *buf
, size_t *len
)
987 rc
= nvmem_reg_read(nvmem
, cell
->offset
, buf
, cell
->bytes
);
992 /* shift bits in-place */
993 if (cell
->bit_offset
|| cell
->nbits
)
994 nvmem_shift_read_buffer_in_place(cell
, buf
);
1003 * nvmem_cell_read() - Read a given nvmem cell
1005 * @cell: nvmem cell to be read.
1006 * @len: pointer to length of cell which will be populated on successful read;
1009 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1010 * buffer should be freed by the consumer with a kfree().
1012 void *nvmem_cell_read(struct nvmem_cell
*cell
, size_t *len
)
1014 struct nvmem_device
*nvmem
= cell
->nvmem
;
1019 return ERR_PTR(-EINVAL
);
1021 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1023 return ERR_PTR(-ENOMEM
);
1025 rc
= __nvmem_cell_read(nvmem
, cell
, buf
, len
);
1033 EXPORT_SYMBOL_GPL(nvmem_cell_read
);
1035 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell
*cell
,
1038 struct nvmem_device
*nvmem
= cell
->nvmem
;
1039 int i
, rc
, nbits
, bit_offset
= cell
->bit_offset
;
1040 u8 v
, *p
, *buf
, *b
, pbyte
, pbits
;
1042 nbits
= cell
->nbits
;
1043 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1045 return ERR_PTR(-ENOMEM
);
1047 memcpy(buf
, _buf
, len
);
1054 /* setup the first byte with lsb bits from nvmem */
1055 rc
= nvmem_reg_read(nvmem
, cell
->offset
, &v
, 1);
1058 *b
++ |= GENMASK(bit_offset
- 1, 0) & v
;
1060 /* setup rest of the byte if any */
1061 for (i
= 1; i
< cell
->bytes
; i
++) {
1062 /* Get last byte bits and shift them towards lsb */
1063 pbits
= pbyte
>> (BITS_PER_BYTE
- 1 - bit_offset
);
1071 /* if it's not end on byte boundary */
1072 if ((nbits
+ bit_offset
) % BITS_PER_BYTE
) {
1073 /* setup the last byte with msb bits from nvmem */
1074 rc
= nvmem_reg_read(nvmem
,
1075 cell
->offset
+ cell
->bytes
- 1, &v
, 1);
1078 *p
|= GENMASK(7, (nbits
+ bit_offset
) % BITS_PER_BYTE
) & v
;
1089 * nvmem_cell_write() - Write to a given nvmem cell
1091 * @cell: nvmem cell to be written.
1092 * @buf: Buffer to be written.
1093 * @len: length of buffer to be written to nvmem cell.
1095 * Return: length of bytes written or negative on failure.
1097 int nvmem_cell_write(struct nvmem_cell
*cell
, void *buf
, size_t len
)
1099 struct nvmem_device
*nvmem
= cell
->nvmem
;
1102 if (!nvmem
|| nvmem
->read_only
||
1103 (cell
->bit_offset
== 0 && len
!= cell
->bytes
))
1106 if (cell
->bit_offset
|| cell
->nbits
) {
1107 buf
= nvmem_cell_prepare_write_buffer(cell
, buf
, len
);
1109 return PTR_ERR(buf
);
1112 rc
= nvmem_reg_write(nvmem
, cell
->offset
, buf
, cell
->bytes
);
1114 /* free the tmp buffer */
1115 if (cell
->bit_offset
|| cell
->nbits
)
1123 EXPORT_SYMBOL_GPL(nvmem_cell_write
);
1126 * nvmem_cell_read_u32() - Read a cell value as an u32
1128 * @dev: Device that requests the nvmem cell.
1129 * @cell_id: Name of nvmem cell to read.
1130 * @val: pointer to output value.
1132 * Return: 0 on success or negative errno.
1134 int nvmem_cell_read_u32(struct device
*dev
, const char *cell_id
, u32
*val
)
1136 struct nvmem_cell
*cell
;
1140 cell
= nvmem_cell_get(dev
, cell_id
);
1142 return PTR_ERR(cell
);
1144 buf
= nvmem_cell_read(cell
, &len
);
1146 nvmem_cell_put(cell
);
1147 return PTR_ERR(buf
);
1149 if (len
!= sizeof(*val
)) {
1151 nvmem_cell_put(cell
);
1154 memcpy(val
, buf
, sizeof(*val
));
1157 nvmem_cell_put(cell
);
1160 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32
);
1163 * nvmem_device_cell_read() - Read a given nvmem device and cell
1165 * @nvmem: nvmem device to read from.
1166 * @info: nvmem cell info to be read.
1167 * @buf: buffer pointer which will be populated on successful read.
1169 * Return: length of successful bytes read on success and negative
1170 * error code on error.
1172 ssize_t
nvmem_device_cell_read(struct nvmem_device
*nvmem
,
1173 struct nvmem_cell_info
*info
, void *buf
)
1175 struct nvmem_cell cell
;
1182 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1186 rc
= __nvmem_cell_read(nvmem
, &cell
, buf
, &len
);
1192 EXPORT_SYMBOL_GPL(nvmem_device_cell_read
);
1195 * nvmem_device_cell_write() - Write cell to a given nvmem device
1197 * @nvmem: nvmem device to be written to.
1198 * @info: nvmem cell info to be written.
1199 * @buf: buffer to be written to cell.
1201 * Return: length of bytes written or negative error code on failure.
1203 int nvmem_device_cell_write(struct nvmem_device
*nvmem
,
1204 struct nvmem_cell_info
*info
, void *buf
)
1206 struct nvmem_cell cell
;
1212 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1216 return nvmem_cell_write(&cell
, buf
, cell
.bytes
);
1218 EXPORT_SYMBOL_GPL(nvmem_device_cell_write
);
1221 * nvmem_device_read() - Read from a given nvmem device
1223 * @nvmem: nvmem device to read from.
1224 * @offset: offset in nvmem device.
1225 * @bytes: number of bytes to read.
1226 * @buf: buffer pointer which will be populated on successful read.
1228 * Return: length of successful bytes read on success and negative
1229 * error code on error.
1231 int nvmem_device_read(struct nvmem_device
*nvmem
,
1232 unsigned int offset
,
1233 size_t bytes
, void *buf
)
1240 rc
= nvmem_reg_read(nvmem
, offset
, buf
, bytes
);
1247 EXPORT_SYMBOL_GPL(nvmem_device_read
);
1250 * nvmem_device_write() - Write cell to a given nvmem device
1252 * @nvmem: nvmem device to be written to.
1253 * @offset: offset in nvmem device.
1254 * @bytes: number of bytes to write.
1255 * @buf: buffer to be written.
1257 * Return: length of bytes written or negative error code on failure.
1259 int nvmem_device_write(struct nvmem_device
*nvmem
,
1260 unsigned int offset
,
1261 size_t bytes
, void *buf
)
1268 rc
= nvmem_reg_write(nvmem
, offset
, buf
, bytes
);
1276 EXPORT_SYMBOL_GPL(nvmem_device_write
);
1278 static int __init
nvmem_init(void)
1280 return bus_register(&nvmem_bus_type
);
1283 static void __exit
nvmem_exit(void)
1285 bus_unregister(&nvmem_bus_type
);
1288 subsys_initcall(nvmem_init
);
1289 module_exit(nvmem_exit
);
1291 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1292 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1293 MODULE_DESCRIPTION("nvmem Driver Core");
1294 MODULE_LICENSE("GPL v2");