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 if (!nvmem
->owner
&& config
->dev
->driver
)
466 nvmem
->owner
= config
->dev
->driver
->owner
;
467 nvmem
->stride
= config
->stride
;
468 nvmem
->word_size
= config
->word_size
;
469 nvmem
->size
= config
->size
;
470 nvmem
->dev
.type
= &nvmem_provider_type
;
471 nvmem
->dev
.bus
= &nvmem_bus_type
;
472 nvmem
->dev
.parent
= config
->dev
;
473 nvmem
->priv
= config
->priv
;
474 nvmem
->reg_read
= config
->reg_read
;
475 nvmem
->reg_write
= config
->reg_write
;
476 np
= config
->dev
->of_node
;
477 nvmem
->dev
.of_node
= np
;
478 dev_set_name(&nvmem
->dev
, "%s%d",
479 config
->name
? : "nvmem",
480 config
->name
? config
->id
: nvmem
->id
);
482 nvmem
->read_only
= of_property_read_bool(np
, "read-only") |
485 if (config
->root_only
)
486 nvmem
->dev
.groups
= nvmem
->read_only
?
487 nvmem_ro_root_dev_groups
:
488 nvmem_rw_root_dev_groups
;
490 nvmem
->dev
.groups
= nvmem
->read_only
?
491 nvmem_ro_dev_groups
:
494 device_initialize(&nvmem
->dev
);
496 dev_dbg(&nvmem
->dev
, "Registering nvmem device %s\n", config
->name
);
498 rval
= device_add(&nvmem
->dev
);
502 if (config
->compat
) {
503 rval
= nvmem_setup_compat(nvmem
, config
);
509 nvmem_add_cells(nvmem
, config
);
514 device_del(&nvmem
->dev
);
516 put_device(&nvmem
->dev
);
518 return ERR_PTR(rval
);
520 EXPORT_SYMBOL_GPL(nvmem_register
);
523 * nvmem_unregister() - Unregister previously registered 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 nvmem_unregister(struct nvmem_device
*nvmem
)
531 mutex_lock(&nvmem_mutex
);
533 mutex_unlock(&nvmem_mutex
);
536 mutex_unlock(&nvmem_mutex
);
538 if (nvmem
->flags
& FLAG_COMPAT
)
539 device_remove_bin_file(nvmem
->base_dev
, &nvmem
->eeprom
);
541 nvmem_device_remove_all_cells(nvmem
);
542 device_del(&nvmem
->dev
);
543 put_device(&nvmem
->dev
);
547 EXPORT_SYMBOL_GPL(nvmem_unregister
);
549 static struct nvmem_device
*__nvmem_device_get(struct device_node
*np
,
550 struct nvmem_cell
**cellp
,
553 struct nvmem_device
*nvmem
= NULL
;
555 mutex_lock(&nvmem_mutex
);
558 nvmem
= of_nvmem_find(np
);
560 mutex_unlock(&nvmem_mutex
);
561 return ERR_PTR(-EPROBE_DEFER
);
564 struct nvmem_cell
*cell
= nvmem_find_cell(cell_id
);
572 mutex_unlock(&nvmem_mutex
);
573 return ERR_PTR(-ENOENT
);
578 mutex_unlock(&nvmem_mutex
);
580 if (!try_module_get(nvmem
->owner
)) {
582 "could not increase module refcount for cell %s\n",
585 mutex_lock(&nvmem_mutex
);
587 mutex_unlock(&nvmem_mutex
);
589 return ERR_PTR(-EINVAL
);
595 static void __nvmem_device_put(struct nvmem_device
*nvmem
)
597 module_put(nvmem
->owner
);
598 mutex_lock(&nvmem_mutex
);
600 mutex_unlock(&nvmem_mutex
);
603 static int nvmem_match(struct device
*dev
, void *data
)
605 return !strcmp(dev_name(dev
), data
);
608 static struct nvmem_device
*nvmem_find(const char *name
)
612 d
= bus_find_device(&nvmem_bus_type
, NULL
, (void *)name
, nvmem_match
);
617 return to_nvmem_device(d
);
620 #if IS_ENABLED(CONFIG_OF)
622 * of_nvmem_device_get() - Get nvmem device from a given id
624 * @np: Device tree node that uses the nvmem device.
625 * @id: nvmem name from nvmem-names property.
627 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
630 struct nvmem_device
*of_nvmem_device_get(struct device_node
*np
, const char *id
)
633 struct device_node
*nvmem_np
;
636 index
= of_property_match_string(np
, "nvmem-names", id
);
638 nvmem_np
= of_parse_phandle(np
, "nvmem", index
);
640 return ERR_PTR(-EINVAL
);
642 return __nvmem_device_get(nvmem_np
, NULL
, NULL
);
644 EXPORT_SYMBOL_GPL(of_nvmem_device_get
);
648 * nvmem_device_get() - Get nvmem device from a given id
650 * @dev: Device that uses the nvmem device.
651 * @dev_name: name of the requested nvmem device.
653 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
656 struct nvmem_device
*nvmem_device_get(struct device
*dev
, const char *dev_name
)
658 if (dev
->of_node
) { /* try dt first */
659 struct nvmem_device
*nvmem
;
661 nvmem
= of_nvmem_device_get(dev
->of_node
, dev_name
);
663 if (!IS_ERR(nvmem
) || PTR_ERR(nvmem
) == -EPROBE_DEFER
)
668 return nvmem_find(dev_name
);
670 EXPORT_SYMBOL_GPL(nvmem_device_get
);
672 static int devm_nvmem_device_match(struct device
*dev
, void *res
, void *data
)
674 struct nvmem_device
**nvmem
= res
;
676 if (WARN_ON(!nvmem
|| !*nvmem
))
679 return *nvmem
== data
;
682 static void devm_nvmem_device_release(struct device
*dev
, void *res
)
684 nvmem_device_put(*(struct nvmem_device
**)res
);
688 * devm_nvmem_device_put() - put alredy got nvmem device
690 * @dev: Device that uses the nvmem device.
691 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
692 * that needs to be released.
694 void devm_nvmem_device_put(struct device
*dev
, struct nvmem_device
*nvmem
)
698 ret
= devres_release(dev
, devm_nvmem_device_release
,
699 devm_nvmem_device_match
, nvmem
);
703 EXPORT_SYMBOL_GPL(devm_nvmem_device_put
);
706 * nvmem_device_put() - put alredy got nvmem device
708 * @nvmem: pointer to nvmem device that needs to be released.
710 void nvmem_device_put(struct nvmem_device
*nvmem
)
712 __nvmem_device_put(nvmem
);
714 EXPORT_SYMBOL_GPL(nvmem_device_put
);
717 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
719 * @dev: Device that requests the nvmem device.
720 * @id: name id for the requested nvmem device.
722 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
723 * on success. The nvmem_cell will be freed by the automatically once the
726 struct nvmem_device
*devm_nvmem_device_get(struct device
*dev
, const char *id
)
728 struct nvmem_device
**ptr
, *nvmem
;
730 ptr
= devres_alloc(devm_nvmem_device_release
, sizeof(*ptr
), GFP_KERNEL
);
732 return ERR_PTR(-ENOMEM
);
734 nvmem
= nvmem_device_get(dev
, id
);
735 if (!IS_ERR(nvmem
)) {
737 devres_add(dev
, ptr
);
744 EXPORT_SYMBOL_GPL(devm_nvmem_device_get
);
746 static struct nvmem_cell
*nvmem_cell_get_from_list(const char *cell_id
)
748 struct nvmem_cell
*cell
= NULL
;
749 struct nvmem_device
*nvmem
;
751 nvmem
= __nvmem_device_get(NULL
, &cell
, cell_id
);
753 return ERR_CAST(nvmem
);
758 #if IS_ENABLED(CONFIG_OF)
760 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
762 * @np: Device tree node that uses the nvmem cell.
763 * @name: nvmem cell name from nvmem-cell-names property, or NULL
764 * for the cell at index 0 (the lone cell with no accompanying
765 * nvmem-cell-names property).
767 * Return: Will be an ERR_PTR() on error or a valid pointer
768 * to a struct nvmem_cell. The nvmem_cell will be freed by the
771 struct nvmem_cell
*of_nvmem_cell_get(struct device_node
*np
,
774 struct device_node
*cell_np
, *nvmem_np
;
775 struct nvmem_cell
*cell
;
776 struct nvmem_device
*nvmem
;
781 /* if cell name exists, find index to the name */
783 index
= of_property_match_string(np
, "nvmem-cell-names", name
);
785 cell_np
= of_parse_phandle(np
, "nvmem-cells", index
);
787 return ERR_PTR(-EINVAL
);
789 nvmem_np
= of_get_next_parent(cell_np
);
791 return ERR_PTR(-EINVAL
);
793 nvmem
= __nvmem_device_get(nvmem_np
, NULL
, NULL
);
794 of_node_put(nvmem_np
);
796 return ERR_CAST(nvmem
);
798 addr
= of_get_property(cell_np
, "reg", &len
);
799 if (!addr
|| (len
< 2 * sizeof(u32
))) {
800 dev_err(&nvmem
->dev
, "nvmem: invalid reg on %pOF\n",
806 cell
= kzalloc(sizeof(*cell
), GFP_KERNEL
);
813 cell
->offset
= be32_to_cpup(addr
++);
814 cell
->bytes
= be32_to_cpup(addr
);
815 cell
->name
= cell_np
->name
;
817 addr
= of_get_property(cell_np
, "bits", &len
);
818 if (addr
&& len
== (2 * sizeof(u32
))) {
819 cell
->bit_offset
= be32_to_cpup(addr
++);
820 cell
->nbits
= be32_to_cpup(addr
);
824 cell
->bytes
= DIV_ROUND_UP(cell
->nbits
+ cell
->bit_offset
,
827 if (!IS_ALIGNED(cell
->offset
, nvmem
->stride
)) {
829 "cell %s unaligned to nvmem stride %d\n",
830 cell
->name
, nvmem
->stride
);
835 nvmem_cell_add(cell
);
843 __nvmem_device_put(nvmem
);
845 return ERR_PTR(rval
);
847 EXPORT_SYMBOL_GPL(of_nvmem_cell_get
);
851 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
853 * @dev: Device that requests the nvmem cell.
854 * @cell_id: nvmem cell name to get.
856 * Return: Will be an ERR_PTR() on error or a valid pointer
857 * to a struct nvmem_cell. The nvmem_cell will be freed by the
860 struct nvmem_cell
*nvmem_cell_get(struct device
*dev
, const char *cell_id
)
862 struct nvmem_cell
*cell
;
864 if (dev
->of_node
) { /* try dt first */
865 cell
= of_nvmem_cell_get(dev
->of_node
, cell_id
);
866 if (!IS_ERR(cell
) || PTR_ERR(cell
) == -EPROBE_DEFER
)
870 return nvmem_cell_get_from_list(cell_id
);
872 EXPORT_SYMBOL_GPL(nvmem_cell_get
);
874 static void devm_nvmem_cell_release(struct device
*dev
, void *res
)
876 nvmem_cell_put(*(struct nvmem_cell
**)res
);
880 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
882 * @dev: Device that requests the nvmem cell.
883 * @id: nvmem cell name id to get.
885 * Return: Will be an ERR_PTR() on error or a valid pointer
886 * to a struct nvmem_cell. The nvmem_cell will be freed by the
887 * automatically once the device is freed.
889 struct nvmem_cell
*devm_nvmem_cell_get(struct device
*dev
, const char *id
)
891 struct nvmem_cell
**ptr
, *cell
;
893 ptr
= devres_alloc(devm_nvmem_cell_release
, sizeof(*ptr
), GFP_KERNEL
);
895 return ERR_PTR(-ENOMEM
);
897 cell
= nvmem_cell_get(dev
, id
);
900 devres_add(dev
, ptr
);
907 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get
);
909 static int devm_nvmem_cell_match(struct device
*dev
, void *res
, void *data
)
911 struct nvmem_cell
**c
= res
;
913 if (WARN_ON(!c
|| !*c
))
920 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
921 * from devm_nvmem_cell_get.
923 * @dev: Device that requests the nvmem cell.
924 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
926 void devm_nvmem_cell_put(struct device
*dev
, struct nvmem_cell
*cell
)
930 ret
= devres_release(dev
, devm_nvmem_cell_release
,
931 devm_nvmem_cell_match
, cell
);
935 EXPORT_SYMBOL(devm_nvmem_cell_put
);
938 * nvmem_cell_put() - Release previously allocated nvmem cell.
940 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
942 void nvmem_cell_put(struct nvmem_cell
*cell
)
944 struct nvmem_device
*nvmem
= cell
->nvmem
;
946 __nvmem_device_put(nvmem
);
947 nvmem_cell_drop(cell
);
949 EXPORT_SYMBOL_GPL(nvmem_cell_put
);
951 static void nvmem_shift_read_buffer_in_place(struct nvmem_cell
*cell
, void *buf
)
954 int i
, bit_offset
= cell
->bit_offset
;
961 /* setup rest of the bytes if any */
962 for (i
= 1; i
< cell
->bytes
; i
++) {
963 /* Get bits from next byte and shift them towards msb */
964 *p
|= *b
<< (BITS_PER_BYTE
- bit_offset
);
970 /* result fits in less bytes */
971 if (cell
->bytes
!= DIV_ROUND_UP(cell
->nbits
, BITS_PER_BYTE
))
974 /* clear msb bits if any leftover in the last byte */
975 *p
&= GENMASK((cell
->nbits
%BITS_PER_BYTE
) - 1, 0);
978 static int __nvmem_cell_read(struct nvmem_device
*nvmem
,
979 struct nvmem_cell
*cell
,
980 void *buf
, size_t *len
)
984 rc
= nvmem_reg_read(nvmem
, cell
->offset
, buf
, cell
->bytes
);
989 /* shift bits in-place */
990 if (cell
->bit_offset
|| cell
->nbits
)
991 nvmem_shift_read_buffer_in_place(cell
, buf
);
1000 * nvmem_cell_read() - Read a given nvmem cell
1002 * @cell: nvmem cell to be read.
1003 * @len: pointer to length of cell which will be populated on successful read;
1006 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
1007 * buffer should be freed by the consumer with a kfree().
1009 void *nvmem_cell_read(struct nvmem_cell
*cell
, size_t *len
)
1011 struct nvmem_device
*nvmem
= cell
->nvmem
;
1016 return ERR_PTR(-EINVAL
);
1018 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1020 return ERR_PTR(-ENOMEM
);
1022 rc
= __nvmem_cell_read(nvmem
, cell
, buf
, len
);
1030 EXPORT_SYMBOL_GPL(nvmem_cell_read
);
1032 static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell
*cell
,
1035 struct nvmem_device
*nvmem
= cell
->nvmem
;
1036 int i
, rc
, nbits
, bit_offset
= cell
->bit_offset
;
1037 u8 v
, *p
, *buf
, *b
, pbyte
, pbits
;
1039 nbits
= cell
->nbits
;
1040 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1042 return ERR_PTR(-ENOMEM
);
1044 memcpy(buf
, _buf
, len
);
1051 /* setup the first byte with lsb bits from nvmem */
1052 rc
= nvmem_reg_read(nvmem
, cell
->offset
, &v
, 1);
1053 *b
++ |= GENMASK(bit_offset
- 1, 0) & v
;
1055 /* setup rest of the byte if any */
1056 for (i
= 1; i
< cell
->bytes
; i
++) {
1057 /* Get last byte bits and shift them towards lsb */
1058 pbits
= pbyte
>> (BITS_PER_BYTE
- 1 - bit_offset
);
1066 /* if it's not end on byte boundary */
1067 if ((nbits
+ bit_offset
) % BITS_PER_BYTE
) {
1068 /* setup the last byte with msb bits from nvmem */
1069 rc
= nvmem_reg_read(nvmem
,
1070 cell
->offset
+ cell
->bytes
- 1, &v
, 1);
1071 *p
|= GENMASK(7, (nbits
+ bit_offset
) % BITS_PER_BYTE
) & v
;
1079 * nvmem_cell_write() - Write to a given nvmem cell
1081 * @cell: nvmem cell to be written.
1082 * @buf: Buffer to be written.
1083 * @len: length of buffer to be written to nvmem cell.
1085 * Return: length of bytes written or negative on failure.
1087 int nvmem_cell_write(struct nvmem_cell
*cell
, void *buf
, size_t len
)
1089 struct nvmem_device
*nvmem
= cell
->nvmem
;
1092 if (!nvmem
|| nvmem
->read_only
||
1093 (cell
->bit_offset
== 0 && len
!= cell
->bytes
))
1096 if (cell
->bit_offset
|| cell
->nbits
) {
1097 buf
= nvmem_cell_prepare_write_buffer(cell
, buf
, len
);
1099 return PTR_ERR(buf
);
1102 rc
= nvmem_reg_write(nvmem
, cell
->offset
, buf
, cell
->bytes
);
1104 /* free the tmp buffer */
1105 if (cell
->bit_offset
|| cell
->nbits
)
1113 EXPORT_SYMBOL_GPL(nvmem_cell_write
);
1116 * nvmem_cell_read_u32() - Read a cell value as an u32
1118 * @dev: Device that requests the nvmem cell.
1119 * @cell_id: Name of nvmem cell to read.
1120 * @val: pointer to output value.
1122 * Return: 0 on success or negative errno.
1124 int nvmem_cell_read_u32(struct device
*dev
, const char *cell_id
, u32
*val
)
1126 struct nvmem_cell
*cell
;
1130 cell
= nvmem_cell_get(dev
, cell_id
);
1132 return PTR_ERR(cell
);
1134 buf
= nvmem_cell_read(cell
, &len
);
1136 nvmem_cell_put(cell
);
1137 return PTR_ERR(buf
);
1139 if (len
!= sizeof(*val
)) {
1141 nvmem_cell_put(cell
);
1144 memcpy(val
, buf
, sizeof(*val
));
1147 nvmem_cell_put(cell
);
1150 EXPORT_SYMBOL_GPL(nvmem_cell_read_u32
);
1153 * nvmem_device_cell_read() - Read a given nvmem device and cell
1155 * @nvmem: nvmem device to read from.
1156 * @info: nvmem cell info to be read.
1157 * @buf: buffer pointer which will be populated on successful read.
1159 * Return: length of successful bytes read on success and negative
1160 * error code on error.
1162 ssize_t
nvmem_device_cell_read(struct nvmem_device
*nvmem
,
1163 struct nvmem_cell_info
*info
, void *buf
)
1165 struct nvmem_cell cell
;
1172 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1176 rc
= __nvmem_cell_read(nvmem
, &cell
, buf
, &len
);
1182 EXPORT_SYMBOL_GPL(nvmem_device_cell_read
);
1185 * nvmem_device_cell_write() - Write cell to a given nvmem device
1187 * @nvmem: nvmem device to be written to.
1188 * @info: nvmem cell info to be written.
1189 * @buf: buffer to be written to cell.
1191 * Return: length of bytes written or negative error code on failure.
1193 int nvmem_device_cell_write(struct nvmem_device
*nvmem
,
1194 struct nvmem_cell_info
*info
, void *buf
)
1196 struct nvmem_cell cell
;
1202 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1206 return nvmem_cell_write(&cell
, buf
, cell
.bytes
);
1208 EXPORT_SYMBOL_GPL(nvmem_device_cell_write
);
1211 * nvmem_device_read() - Read from a given nvmem device
1213 * @nvmem: nvmem device to read from.
1214 * @offset: offset in nvmem device.
1215 * @bytes: number of bytes to read.
1216 * @buf: buffer pointer which will be populated on successful read.
1218 * Return: length of successful bytes read on success and negative
1219 * error code on error.
1221 int nvmem_device_read(struct nvmem_device
*nvmem
,
1222 unsigned int offset
,
1223 size_t bytes
, void *buf
)
1230 rc
= nvmem_reg_read(nvmem
, offset
, buf
, bytes
);
1237 EXPORT_SYMBOL_GPL(nvmem_device_read
);
1240 * nvmem_device_write() - Write cell to a given nvmem device
1242 * @nvmem: nvmem device to be written to.
1243 * @offset: offset in nvmem device.
1244 * @bytes: number of bytes to write.
1245 * @buf: buffer to be written.
1247 * Return: length of bytes written or negative error code on failure.
1249 int nvmem_device_write(struct nvmem_device
*nvmem
,
1250 unsigned int offset
,
1251 size_t bytes
, void *buf
)
1258 rc
= nvmem_reg_write(nvmem
, offset
, buf
, bytes
);
1266 EXPORT_SYMBOL_GPL(nvmem_device_write
);
1268 static int __init
nvmem_init(void)
1270 return bus_register(&nvmem_bus_type
);
1273 static void __exit
nvmem_exit(void)
1275 bus_unregister(&nvmem_bus_type
);
1278 subsys_initcall(nvmem_init
);
1279 module_exit(nvmem_exit
);
1281 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1282 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1283 MODULE_DESCRIPTION("nvmem Driver Core");
1284 MODULE_LICENSE("GPL v2");