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 list_for_each_entry(p
, &nvmem_cells
, node
)
291 if (p
&& !strcmp(p
->name
, cell_id
))
297 static void nvmem_cell_drop(struct nvmem_cell
*cell
)
299 mutex_lock(&nvmem_cells_mutex
);
300 list_del(&cell
->node
);
301 mutex_unlock(&nvmem_cells_mutex
);
305 static void nvmem_device_remove_all_cells(const struct nvmem_device
*nvmem
)
307 struct nvmem_cell
*cell
;
308 struct list_head
*p
, *n
;
310 list_for_each_safe(p
, n
, &nvmem_cells
) {
311 cell
= list_entry(p
, struct nvmem_cell
, node
);
312 if (cell
->nvmem
== nvmem
)
313 nvmem_cell_drop(cell
);
317 static void nvmem_cell_add(struct nvmem_cell
*cell
)
319 mutex_lock(&nvmem_cells_mutex
);
320 list_add_tail(&cell
->node
, &nvmem_cells
);
321 mutex_unlock(&nvmem_cells_mutex
);
324 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device
*nvmem
,
325 const struct nvmem_cell_info
*info
,
326 struct nvmem_cell
*cell
)
329 cell
->offset
= info
->offset
;
330 cell
->bytes
= info
->bytes
;
331 cell
->name
= info
->name
;
333 cell
->bit_offset
= info
->bit_offset
;
334 cell
->nbits
= info
->nbits
;
337 cell
->bytes
= DIV_ROUND_UP(cell
->nbits
+ cell
->bit_offset
,
340 if (!IS_ALIGNED(cell
->offset
, nvmem
->stride
)) {
342 "cell %s unaligned to nvmem stride %d\n",
343 cell
->name
, nvmem
->stride
);
350 static int nvmem_add_cells(struct nvmem_device
*nvmem
,
351 const struct nvmem_config
*cfg
)
353 struct nvmem_cell
**cells
;
354 const struct nvmem_cell_info
*info
= cfg
->cells
;
357 cells
= kcalloc(cfg
->ncells
, sizeof(*cells
), GFP_KERNEL
);
361 for (i
= 0; i
< cfg
->ncells
; i
++) {
362 cells
[i
] = kzalloc(sizeof(**cells
), GFP_KERNEL
);
368 rval
= nvmem_cell_info_to_nvmem_cell(nvmem
, &info
[i
], cells
[i
]);
374 nvmem_cell_add(cells
[i
]);
377 nvmem
->ncells
= cfg
->ncells
;
378 /* remove tmp array */
384 nvmem_cell_drop(cells
[i
]);
392 * nvmem_setup_compat() - Create an additional binary entry in
393 * drivers sys directory, to be backwards compatible with the older
394 * drivers/misc/eeprom drivers.
396 static int nvmem_setup_compat(struct nvmem_device
*nvmem
,
397 const struct nvmem_config
*config
)
401 if (!config
->base_dev
)
404 if (nvmem
->read_only
)
405 nvmem
->eeprom
= bin_attr_ro_root_nvmem
;
407 nvmem
->eeprom
= bin_attr_rw_root_nvmem
;
408 nvmem
->eeprom
.attr
.name
= "eeprom";
409 nvmem
->eeprom
.size
= nvmem
->size
;
410 #ifdef CONFIG_DEBUG_LOCK_ALLOC
411 nvmem
->eeprom
.attr
.key
= &eeprom_lock_key
;
413 nvmem
->eeprom
.private = &nvmem
->dev
;
414 nvmem
->base_dev
= config
->base_dev
;
416 rval
= device_create_bin_file(nvmem
->base_dev
, &nvmem
->eeprom
);
419 "Failed to create eeprom binary file %d\n", rval
);
423 nvmem
->flags
|= FLAG_COMPAT
;
429 * nvmem_register() - Register a nvmem device for given nvmem_config.
430 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
432 * @config: nvmem device configuration with which nvmem device is created.
434 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
438 struct nvmem_device
*nvmem_register(const struct nvmem_config
*config
)
440 struct nvmem_device
*nvmem
;
441 struct device_node
*np
;
445 return ERR_PTR(-EINVAL
);
447 nvmem
= kzalloc(sizeof(*nvmem
), GFP_KERNEL
);
449 return ERR_PTR(-ENOMEM
);
451 rval
= ida_simple_get(&nvmem_ida
, 0, 0, GFP_KERNEL
);
454 return ERR_PTR(rval
);
458 nvmem
->owner
= config
->owner
;
459 nvmem
->stride
= config
->stride
;
460 nvmem
->word_size
= config
->word_size
;
461 nvmem
->size
= config
->size
;
462 nvmem
->dev
.type
= &nvmem_provider_type
;
463 nvmem
->dev
.bus
= &nvmem_bus_type
;
464 nvmem
->dev
.parent
= config
->dev
;
465 nvmem
->priv
= config
->priv
;
466 nvmem
->reg_read
= config
->reg_read
;
467 nvmem
->reg_write
= config
->reg_write
;
468 np
= config
->dev
->of_node
;
469 nvmem
->dev
.of_node
= np
;
470 dev_set_name(&nvmem
->dev
, "%s%d",
471 config
->name
? : "nvmem",
472 config
->name
? config
->id
: nvmem
->id
);
474 nvmem
->read_only
= of_property_read_bool(np
, "read-only") |
477 if (config
->root_only
)
478 nvmem
->dev
.groups
= nvmem
->read_only
?
479 nvmem_ro_root_dev_groups
:
480 nvmem_rw_root_dev_groups
;
482 nvmem
->dev
.groups
= nvmem
->read_only
?
483 nvmem_ro_dev_groups
:
486 device_initialize(&nvmem
->dev
);
488 dev_dbg(&nvmem
->dev
, "Registering nvmem device %s\n", config
->name
);
490 rval
= device_add(&nvmem
->dev
);
494 if (config
->compat
) {
495 rval
= nvmem_setup_compat(nvmem
, config
);
501 nvmem_add_cells(nvmem
, config
);
505 ida_simple_remove(&nvmem_ida
, nvmem
->id
);
507 return ERR_PTR(rval
);
509 EXPORT_SYMBOL_GPL(nvmem_register
);
512 * nvmem_unregister() - Unregister previously registered nvmem device
514 * @nvmem: Pointer to previously registered nvmem device.
516 * Return: Will be an negative on error or a zero on success.
518 int nvmem_unregister(struct nvmem_device
*nvmem
)
520 mutex_lock(&nvmem_mutex
);
522 mutex_unlock(&nvmem_mutex
);
525 mutex_unlock(&nvmem_mutex
);
527 if (nvmem
->flags
& FLAG_COMPAT
)
528 device_remove_bin_file(nvmem
->base_dev
, &nvmem
->eeprom
);
530 nvmem_device_remove_all_cells(nvmem
);
531 device_del(&nvmem
->dev
);
535 EXPORT_SYMBOL_GPL(nvmem_unregister
);
537 static struct nvmem_device
*__nvmem_device_get(struct device_node
*np
,
538 struct nvmem_cell
**cellp
,
541 struct nvmem_device
*nvmem
= NULL
;
543 mutex_lock(&nvmem_mutex
);
546 nvmem
= of_nvmem_find(np
);
548 mutex_unlock(&nvmem_mutex
);
549 return ERR_PTR(-EPROBE_DEFER
);
552 struct nvmem_cell
*cell
= nvmem_find_cell(cell_id
);
560 mutex_unlock(&nvmem_mutex
);
561 return ERR_PTR(-ENOENT
);
566 mutex_unlock(&nvmem_mutex
);
568 if (!try_module_get(nvmem
->owner
)) {
570 "could not increase module refcount for cell %s\n",
573 mutex_lock(&nvmem_mutex
);
575 mutex_unlock(&nvmem_mutex
);
577 return ERR_PTR(-EINVAL
);
583 static void __nvmem_device_put(struct nvmem_device
*nvmem
)
585 module_put(nvmem
->owner
);
586 mutex_lock(&nvmem_mutex
);
588 mutex_unlock(&nvmem_mutex
);
591 static int nvmem_match(struct device
*dev
, void *data
)
593 return !strcmp(dev_name(dev
), data
);
596 static struct nvmem_device
*nvmem_find(const char *name
)
600 d
= bus_find_device(&nvmem_bus_type
, NULL
, (void *)name
, nvmem_match
);
605 return to_nvmem_device(d
);
608 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
610 * of_nvmem_device_get() - Get nvmem device from a given id
612 * @np: Device tree node that uses the nvmem device.
613 * @id: nvmem name from nvmem-names property.
615 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
618 struct nvmem_device
*of_nvmem_device_get(struct device_node
*np
, const char *id
)
621 struct device_node
*nvmem_np
;
624 index
= of_property_match_string(np
, "nvmem-names", id
);
626 nvmem_np
= of_parse_phandle(np
, "nvmem", index
);
628 return ERR_PTR(-EINVAL
);
630 return __nvmem_device_get(nvmem_np
, NULL
, NULL
);
632 EXPORT_SYMBOL_GPL(of_nvmem_device_get
);
636 * nvmem_device_get() - Get nvmem device from a given id
638 * @dev: Device that uses the nvmem device.
639 * @dev_name: name of the requested nvmem device.
641 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
644 struct nvmem_device
*nvmem_device_get(struct device
*dev
, const char *dev_name
)
646 if (dev
->of_node
) { /* try dt first */
647 struct nvmem_device
*nvmem
;
649 nvmem
= of_nvmem_device_get(dev
->of_node
, dev_name
);
651 if (!IS_ERR(nvmem
) || PTR_ERR(nvmem
) == -EPROBE_DEFER
)
656 return nvmem_find(dev_name
);
658 EXPORT_SYMBOL_GPL(nvmem_device_get
);
660 static int devm_nvmem_device_match(struct device
*dev
, void *res
, void *data
)
662 struct nvmem_device
**nvmem
= res
;
664 if (WARN_ON(!nvmem
|| !*nvmem
))
667 return *nvmem
== data
;
670 static void devm_nvmem_device_release(struct device
*dev
, void *res
)
672 nvmem_device_put(*(struct nvmem_device
**)res
);
676 * devm_nvmem_device_put() - put alredy got nvmem device
678 * @dev: Device that uses the nvmem device.
679 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
680 * that needs to be released.
682 void devm_nvmem_device_put(struct device
*dev
, struct nvmem_device
*nvmem
)
686 ret
= devres_release(dev
, devm_nvmem_device_release
,
687 devm_nvmem_device_match
, nvmem
);
691 EXPORT_SYMBOL_GPL(devm_nvmem_device_put
);
694 * nvmem_device_put() - put alredy got nvmem device
696 * @nvmem: pointer to nvmem device that needs to be released.
698 void nvmem_device_put(struct nvmem_device
*nvmem
)
700 __nvmem_device_put(nvmem
);
702 EXPORT_SYMBOL_GPL(nvmem_device_put
);
705 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
707 * @dev: Device that requests the nvmem device.
708 * @id: name id for the requested nvmem device.
710 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
711 * on success. The nvmem_cell will be freed by the automatically once the
714 struct nvmem_device
*devm_nvmem_device_get(struct device
*dev
, const char *id
)
716 struct nvmem_device
**ptr
, *nvmem
;
718 ptr
= devres_alloc(devm_nvmem_device_release
, sizeof(*ptr
), GFP_KERNEL
);
720 return ERR_PTR(-ENOMEM
);
722 nvmem
= nvmem_device_get(dev
, id
);
723 if (!IS_ERR(nvmem
)) {
725 devres_add(dev
, ptr
);
732 EXPORT_SYMBOL_GPL(devm_nvmem_device_get
);
734 static struct nvmem_cell
*nvmem_cell_get_from_list(const char *cell_id
)
736 struct nvmem_cell
*cell
= NULL
;
737 struct nvmem_device
*nvmem
;
739 nvmem
= __nvmem_device_get(NULL
, &cell
, cell_id
);
741 return ERR_CAST(nvmem
);
746 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
748 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
750 * @np: Device tree node that uses the nvmem cell.
751 * @name: nvmem cell name from nvmem-cell-names property, or NULL
752 * for the cell at index 0 (the lone cell with no accompanying
753 * nvmem-cell-names property).
755 * Return: Will be an ERR_PTR() on error or a valid pointer
756 * to a struct nvmem_cell. The nvmem_cell will be freed by the
759 struct nvmem_cell
*of_nvmem_cell_get(struct device_node
*np
,
762 struct device_node
*cell_np
, *nvmem_np
;
763 struct nvmem_cell
*cell
;
764 struct nvmem_device
*nvmem
;
769 /* if cell name exists, find index to the name */
771 index
= of_property_match_string(np
, "nvmem-cell-names", name
);
773 cell_np
= of_parse_phandle(np
, "nvmem-cells", index
);
775 return ERR_PTR(-EINVAL
);
777 nvmem_np
= of_get_next_parent(cell_np
);
779 return ERR_PTR(-EINVAL
);
781 nvmem
= __nvmem_device_get(nvmem_np
, NULL
, NULL
);
783 return ERR_CAST(nvmem
);
785 addr
= of_get_property(cell_np
, "reg", &len
);
786 if (!addr
|| (len
< 2 * sizeof(u32
))) {
787 dev_err(&nvmem
->dev
, "nvmem: invalid reg on %s\n",
793 cell
= kzalloc(sizeof(*cell
), GFP_KERNEL
);
800 cell
->offset
= be32_to_cpup(addr
++);
801 cell
->bytes
= be32_to_cpup(addr
);
802 cell
->name
= cell_np
->name
;
804 addr
= of_get_property(cell_np
, "bits", &len
);
805 if (addr
&& len
== (2 * sizeof(u32
))) {
806 cell
->bit_offset
= be32_to_cpup(addr
++);
807 cell
->nbits
= be32_to_cpup(addr
);
811 cell
->bytes
= DIV_ROUND_UP(cell
->nbits
+ cell
->bit_offset
,
814 if (!IS_ALIGNED(cell
->offset
, nvmem
->stride
)) {
816 "cell %s unaligned to nvmem stride %d\n",
817 cell
->name
, nvmem
->stride
);
822 nvmem_cell_add(cell
);
830 __nvmem_device_put(nvmem
);
832 return ERR_PTR(rval
);
834 EXPORT_SYMBOL_GPL(of_nvmem_cell_get
);
838 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
840 * @dev: Device that requests the nvmem cell.
841 * @cell_id: nvmem cell name to get.
843 * Return: Will be an ERR_PTR() on error or a valid pointer
844 * to a struct nvmem_cell. The nvmem_cell will be freed by the
847 struct nvmem_cell
*nvmem_cell_get(struct device
*dev
, const char *cell_id
)
849 struct nvmem_cell
*cell
;
851 if (dev
->of_node
) { /* try dt first */
852 cell
= of_nvmem_cell_get(dev
->of_node
, cell_id
);
853 if (!IS_ERR(cell
) || PTR_ERR(cell
) == -EPROBE_DEFER
)
857 return nvmem_cell_get_from_list(cell_id
);
859 EXPORT_SYMBOL_GPL(nvmem_cell_get
);
861 static void devm_nvmem_cell_release(struct device
*dev
, void *res
)
863 nvmem_cell_put(*(struct nvmem_cell
**)res
);
867 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
869 * @dev: Device that requests the nvmem cell.
870 * @id: nvmem cell name id to get.
872 * Return: Will be an ERR_PTR() on error or a valid pointer
873 * to a struct nvmem_cell. The nvmem_cell will be freed by the
874 * automatically once the device is freed.
876 struct nvmem_cell
*devm_nvmem_cell_get(struct device
*dev
, const char *id
)
878 struct nvmem_cell
**ptr
, *cell
;
880 ptr
= devres_alloc(devm_nvmem_cell_release
, sizeof(*ptr
), GFP_KERNEL
);
882 return ERR_PTR(-ENOMEM
);
884 cell
= nvmem_cell_get(dev
, id
);
887 devres_add(dev
, ptr
);
894 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get
);
896 static int devm_nvmem_cell_match(struct device
*dev
, void *res
, void *data
)
898 struct nvmem_cell
**c
= res
;
900 if (WARN_ON(!c
|| !*c
))
907 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
908 * from devm_nvmem_cell_get.
910 * @dev: Device that requests the nvmem cell.
911 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
913 void devm_nvmem_cell_put(struct device
*dev
, struct nvmem_cell
*cell
)
917 ret
= devres_release(dev
, devm_nvmem_cell_release
,
918 devm_nvmem_cell_match
, cell
);
922 EXPORT_SYMBOL(devm_nvmem_cell_put
);
925 * nvmem_cell_put() - Release previously allocated nvmem cell.
927 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
929 void nvmem_cell_put(struct nvmem_cell
*cell
)
931 struct nvmem_device
*nvmem
= cell
->nvmem
;
933 __nvmem_device_put(nvmem
);
934 nvmem_cell_drop(cell
);
936 EXPORT_SYMBOL_GPL(nvmem_cell_put
);
938 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell
*cell
,
942 int i
, bit_offset
= cell
->bit_offset
;
949 /* setup rest of the bytes if any */
950 for (i
= 1; i
< cell
->bytes
; i
++) {
951 /* Get bits from next byte and shift them towards msb */
952 *p
|= *b
<< (BITS_PER_BYTE
- bit_offset
);
958 /* result fits in less bytes */
959 if (cell
->bytes
!= DIV_ROUND_UP(cell
->nbits
, BITS_PER_BYTE
))
962 /* clear msb bits if any leftover in the last byte */
963 *p
&= GENMASK((cell
->nbits
%BITS_PER_BYTE
) - 1, 0);
966 static int __nvmem_cell_read(struct nvmem_device
*nvmem
,
967 struct nvmem_cell
*cell
,
968 void *buf
, size_t *len
)
972 rc
= nvmem_reg_read(nvmem
, cell
->offset
, buf
, cell
->bytes
);
977 /* shift bits in-place */
978 if (cell
->bit_offset
|| cell
->nbits
)
979 nvmem_shift_read_buffer_in_place(cell
, buf
);
988 * nvmem_cell_read() - Read a given nvmem cell
990 * @cell: nvmem cell to be read.
991 * @len: pointer to length of cell which will be populated on successful read;
994 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
995 * buffer should be freed by the consumer with a kfree().
997 void *nvmem_cell_read(struct nvmem_cell
*cell
, size_t *len
)
999 struct nvmem_device
*nvmem
= cell
->nvmem
;
1004 return ERR_PTR(-EINVAL
);
1006 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1008 return ERR_PTR(-ENOMEM
);
1010 rc
= __nvmem_cell_read(nvmem
, cell
, buf
, len
);
1018 EXPORT_SYMBOL_GPL(nvmem_cell_read
);
1020 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell
*cell
,
1023 struct nvmem_device
*nvmem
= cell
->nvmem
;
1024 int i
, rc
, nbits
, bit_offset
= cell
->bit_offset
;
1025 u8 v
, *p
, *buf
, *b
, pbyte
, pbits
;
1027 nbits
= cell
->nbits
;
1028 buf
= kzalloc(cell
->bytes
, GFP_KERNEL
);
1030 return ERR_PTR(-ENOMEM
);
1032 memcpy(buf
, _buf
, len
);
1039 /* setup the first byte with lsb bits from nvmem */
1040 rc
= nvmem_reg_read(nvmem
, cell
->offset
, &v
, 1);
1041 *b
++ |= GENMASK(bit_offset
- 1, 0) & v
;
1043 /* setup rest of the byte if any */
1044 for (i
= 1; i
< cell
->bytes
; i
++) {
1045 /* Get last byte bits and shift them towards lsb */
1046 pbits
= pbyte
>> (BITS_PER_BYTE
- 1 - bit_offset
);
1054 /* if it's not end on byte boundary */
1055 if ((nbits
+ bit_offset
) % BITS_PER_BYTE
) {
1056 /* setup the last byte with msb bits from nvmem */
1057 rc
= nvmem_reg_read(nvmem
,
1058 cell
->offset
+ cell
->bytes
- 1, &v
, 1);
1059 *p
|= GENMASK(7, (nbits
+ bit_offset
) % BITS_PER_BYTE
) & v
;
1067 * nvmem_cell_write() - Write to a given nvmem cell
1069 * @cell: nvmem cell to be written.
1070 * @buf: Buffer to be written.
1071 * @len: length of buffer to be written to nvmem cell.
1073 * Return: length of bytes written or negative on failure.
1075 int nvmem_cell_write(struct nvmem_cell
*cell
, void *buf
, size_t len
)
1077 struct nvmem_device
*nvmem
= cell
->nvmem
;
1080 if (!nvmem
|| nvmem
->read_only
||
1081 (cell
->bit_offset
== 0 && len
!= cell
->bytes
))
1084 if (cell
->bit_offset
|| cell
->nbits
) {
1085 buf
= nvmem_cell_prepare_write_buffer(cell
, buf
, len
);
1087 return PTR_ERR(buf
);
1090 rc
= nvmem_reg_write(nvmem
, cell
->offset
, buf
, cell
->bytes
);
1092 /* free the tmp buffer */
1093 if (cell
->bit_offset
|| cell
->nbits
)
1101 EXPORT_SYMBOL_GPL(nvmem_cell_write
);
1104 * nvmem_device_cell_read() - Read a given nvmem device and cell
1106 * @nvmem: nvmem device to read from.
1107 * @info: nvmem cell info to be read.
1108 * @buf: buffer pointer which will be populated on successful read.
1110 * Return: length of successful bytes read on success and negative
1111 * error code on error.
1113 ssize_t
nvmem_device_cell_read(struct nvmem_device
*nvmem
,
1114 struct nvmem_cell_info
*info
, void *buf
)
1116 struct nvmem_cell cell
;
1123 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1127 rc
= __nvmem_cell_read(nvmem
, &cell
, buf
, &len
);
1133 EXPORT_SYMBOL_GPL(nvmem_device_cell_read
);
1136 * nvmem_device_cell_write() - Write cell to a given nvmem device
1138 * @nvmem: nvmem device to be written to.
1139 * @info: nvmem cell info to be written.
1140 * @buf: buffer to be written to cell.
1142 * Return: length of bytes written or negative error code on failure.
1144 int nvmem_device_cell_write(struct nvmem_device
*nvmem
,
1145 struct nvmem_cell_info
*info
, void *buf
)
1147 struct nvmem_cell cell
;
1153 rc
= nvmem_cell_info_to_nvmem_cell(nvmem
, info
, &cell
);
1157 return nvmem_cell_write(&cell
, buf
, cell
.bytes
);
1159 EXPORT_SYMBOL_GPL(nvmem_device_cell_write
);
1162 * nvmem_device_read() - Read from a given nvmem device
1164 * @nvmem: nvmem device to read from.
1165 * @offset: offset in nvmem device.
1166 * @bytes: number of bytes to 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 int nvmem_device_read(struct nvmem_device
*nvmem
,
1173 unsigned int offset
,
1174 size_t bytes
, void *buf
)
1181 rc
= nvmem_reg_read(nvmem
, offset
, buf
, bytes
);
1188 EXPORT_SYMBOL_GPL(nvmem_device_read
);
1191 * nvmem_device_write() - Write cell to a given nvmem device
1193 * @nvmem: nvmem device to be written to.
1194 * @offset: offset in nvmem device.
1195 * @bytes: number of bytes to write.
1196 * @buf: buffer to be written.
1198 * Return: length of bytes written or negative error code on failure.
1200 int nvmem_device_write(struct nvmem_device
*nvmem
,
1201 unsigned int offset
,
1202 size_t bytes
, void *buf
)
1209 rc
= nvmem_reg_write(nvmem
, offset
, buf
, bytes
);
1217 EXPORT_SYMBOL_GPL(nvmem_device_write
);
1219 static int __init
nvmem_init(void)
1221 return bus_register(&nvmem_bus_type
);
1224 static void __exit
nvmem_exit(void)
1226 bus_unregister(&nvmem_bus_type
);
1229 subsys_initcall(nvmem_init
);
1230 module_exit(nvmem_exit
);
1232 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1233 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1234 MODULE_DESCRIPTION("nvmem Driver Core");
1235 MODULE_LICENSE("GPL v2");