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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * nvmem framework core.
4 *
5 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
6 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
7 */
8
9#include <linux/device.h>
10#include <linux/export.h>
11#include <linux/fs.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>
18#include <linux/of.h>
19#include <linux/slab.h>
20#include "nvmem.h"
21
22struct nvmem_cell {
23 const char *name;
24 int offset;
25 int bytes;
26 int bit_offset;
27 int nbits;
28 struct device_node *np;
29 struct nvmem_device *nvmem;
30 struct list_head node;
31};
32
33static DEFINE_MUTEX(nvmem_mutex);
34static DEFINE_IDA(nvmem_ida);
35
36static DEFINE_MUTEX(nvmem_cell_mutex);
37static LIST_HEAD(nvmem_cell_tables);
38
39static DEFINE_MUTEX(nvmem_lookup_mutex);
40static LIST_HEAD(nvmem_lookup_list);
41
42static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
43
44
45static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
46 void *val, size_t bytes)
47{
48 if (nvmem->reg_read)
49 return nvmem->reg_read(nvmem->priv, offset, val, bytes);
50
51 return -EINVAL;
52}
53
54static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
55 void *val, size_t bytes)
56{
57 if (nvmem->reg_write)
58 return nvmem->reg_write(nvmem->priv, offset, val, bytes);
59
60 return -EINVAL;
61}
62
63static void nvmem_release(struct device *dev)
64{
65 struct nvmem_device *nvmem = to_nvmem_device(dev);
66
67 ida_simple_remove(&nvmem_ida, nvmem->id);
68 kfree(nvmem);
69}
70
71static const struct device_type nvmem_provider_type = {
72 .release = nvmem_release,
73};
74
75static struct bus_type nvmem_bus_type = {
76 .name = "nvmem",
77};
78
79static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
80{
81 struct device *d;
82
83 if (!nvmem_np)
84 return NULL;
85
86 d = bus_find_device_by_of_node(&nvmem_bus_type, nvmem_np);
87
88 if (!d)
89 return NULL;
90
91 return to_nvmem_device(d);
92}
93
94static struct nvmem_device *nvmem_find(const char *name)
95{
96 struct device *d;
97
98 d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
99
100 if (!d)
101 return NULL;
102
103 return to_nvmem_device(d);
104}
105
106static void nvmem_cell_drop(struct nvmem_cell *cell)
107{
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);
113 kfree(cell->name);
114 kfree(cell);
115}
116
117static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
118{
119 struct nvmem_cell *cell, *p;
120
121 list_for_each_entry_safe(cell, p, &nvmem->cells, node)
122 nvmem_cell_drop(cell);
123}
124
125static void nvmem_cell_add(struct nvmem_cell *cell)
126{
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);
131}
132
133static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
134 const struct nvmem_cell_info *info,
135 struct nvmem_cell *cell)
136{
137 cell->nvmem = nvmem;
138 cell->offset = info->offset;
139 cell->bytes = info->bytes;
140 cell->name = info->name;
141
142 cell->bit_offset = info->bit_offset;
143 cell->nbits = info->nbits;
144
145 if (cell->nbits)
146 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
147 BITS_PER_BYTE);
148
149 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
150 dev_err(&nvmem->dev,
151 "cell %s unaligned to nvmem stride %d\n",
152 cell->name, nvmem->stride);
153 return -EINVAL;
154 }
155
156 return 0;
157}
158
159/**
160 * nvmem_add_cells() - Add cell information to an nvmem device
161 *
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
165 *
166 * Return: 0 or negative error code on failure.
167 */
168static int nvmem_add_cells(struct nvmem_device *nvmem,
169 const struct nvmem_cell_info *info,
170 int ncells)
171{
172 struct nvmem_cell **cells;
173 int i, rval;
174
175 cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
176 if (!cells)
177 return -ENOMEM;
178
179 for (i = 0; i < ncells; i++) {
180 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
181 if (!cells[i]) {
182 rval = -ENOMEM;
183 goto err;
184 }
185
186 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
187 if (rval) {
188 kfree(cells[i]);
189 goto err;
190 }
191
192 nvmem_cell_add(cells[i]);
193 }
194
195 /* remove tmp array */
196 kfree(cells);
197
198 return 0;
199err:
200 while (i--)
201 nvmem_cell_drop(cells[i]);
202
203 kfree(cells);
204
205 return rval;
206}
207
208/**
209 * nvmem_register_notifier() - Register a notifier block for nvmem events.
210 *
211 * @nb: notifier block to be called on nvmem events.
212 *
213 * Return: 0 on success, negative error number on failure.
214 */
215int nvmem_register_notifier(struct notifier_block *nb)
216{
217 return blocking_notifier_chain_register(&nvmem_notifier, nb);
218}
219EXPORT_SYMBOL_GPL(nvmem_register_notifier);
220
221/**
222 * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
223 *
224 * @nb: notifier block to be unregistered.
225 *
226 * Return: 0 on success, negative error number on failure.
227 */
228int nvmem_unregister_notifier(struct notifier_block *nb)
229{
230 return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
231}
232EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
233
234static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
235{
236 const struct nvmem_cell_info *info;
237 struct nvmem_cell_table *table;
238 struct nvmem_cell *cell;
239 int rval = 0, i;
240
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];
246
247 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
248 if (!cell) {
249 rval = -ENOMEM;
250 goto out;
251 }
252
253 rval = nvmem_cell_info_to_nvmem_cell(nvmem,
254 info,
255 cell);
256 if (rval) {
257 kfree(cell);
258 goto out;
259 }
260
261 nvmem_cell_add(cell);
262 }
263 }
264 }
265
266out:
267 mutex_unlock(&nvmem_cell_mutex);
268 return rval;
269}
270
271static struct nvmem_cell *
272nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
273{
274 struct nvmem_cell *iter, *cell = NULL;
275
276 mutex_lock(&nvmem_mutex);
277 list_for_each_entry(iter, &nvmem->cells, node) {
278 if (strcmp(cell_id, iter->name) == 0) {
279 cell = iter;
280 break;
281 }
282 }
283 mutex_unlock(&nvmem_mutex);
284
285 return cell;
286}
287
288static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
289{
290 struct device_node *parent, *child;
291 struct device *dev = &nvmem->dev;
292 struct nvmem_cell *cell;
293 const __be32 *addr;
294 int len;
295
296 parent = dev->of_node;
297
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);
302 return -EINVAL;
303 }
304
305 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
306 if (!cell)
307 return -ENOMEM;
308
309 cell->nvmem = nvmem;
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);
314
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);
319 }
320
321 if (cell->nbits)
322 cell->bytes = DIV_ROUND_UP(
323 cell->nbits + cell->bit_offset,
324 BITS_PER_BYTE);
325
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. */
330 kfree(cell->name);
331 kfree(cell);
332 return -EINVAL;
333 }
334
335 nvmem_cell_add(cell);
336 }
337
338 return 0;
339}
340
341/**
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
344 *
345 * @config: nvmem device configuration with which nvmem device is created.
346 *
347 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
348 * on success.
349 */
350
351struct nvmem_device *nvmem_register(const struct nvmem_config *config)
352{
353 struct nvmem_device *nvmem;
354 int rval;
355
356 if (!config->dev)
357 return ERR_PTR(-EINVAL);
358
359 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
360 if (!nvmem)
361 return ERR_PTR(-ENOMEM);
362
363 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
364 if (rval < 0) {
365 kfree(nvmem);
366 return ERR_PTR(rval);
367 }
368
369 kref_init(&nvmem->refcnt);
370 INIT_LIST_HEAD(&nvmem->cells);
371
372 nvmem->id = rval;
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;
388
389 if (config->id == -1 && config->name) {
390 dev_set_name(&nvmem->dev, "%s", config->name);
391 } else {
392 dev_set_name(&nvmem->dev, "%s%d",
393 config->name ? : "nvmem",
394 config->name ? config->id : nvmem->id);
395 }
396
397 nvmem->read_only = device_property_present(config->dev, "read-only") ||
398 config->read_only || !nvmem->reg_write;
399
400 nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config);
401
402 device_initialize(&nvmem->dev);
403
404 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
405
406 rval = device_add(&nvmem->dev);
407 if (rval)
408 goto err_put_device;
409
410 if (config->compat) {
411 rval = nvmem_sysfs_setup_compat(nvmem, config);
412 if (rval)
413 goto err_device_del;
414 }
415
416 if (config->cells) {
417 rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
418 if (rval)
419 goto err_teardown_compat;
420 }
421
422 rval = nvmem_add_cells_from_table(nvmem);
423 if (rval)
424 goto err_remove_cells;
425
426 rval = nvmem_add_cells_from_of(nvmem);
427 if (rval)
428 goto err_remove_cells;
429
430 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
431
432 return nvmem;
433
434err_remove_cells:
435 nvmem_device_remove_all_cells(nvmem);
436err_teardown_compat:
437 if (config->compat)
438 nvmem_sysfs_remove_compat(nvmem, config);
439err_device_del:
440 device_del(&nvmem->dev);
441err_put_device:
442 put_device(&nvmem->dev);
443
444 return ERR_PTR(rval);
445}
446EXPORT_SYMBOL_GPL(nvmem_register);
447
448static void nvmem_device_release(struct kref *kref)
449{
450 struct nvmem_device *nvmem;
451
452 nvmem = container_of(kref, struct nvmem_device, refcnt);
453
454 blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
455
456 if (nvmem->flags & FLAG_COMPAT)
457 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
458
459 nvmem_device_remove_all_cells(nvmem);
460 device_del(&nvmem->dev);
461 put_device(&nvmem->dev);
462}
463
464/**
465 * nvmem_unregister() - Unregister previously registered nvmem device
466 *
467 * @nvmem: Pointer to previously registered nvmem device.
468 */
469void nvmem_unregister(struct nvmem_device *nvmem)
470{
471 kref_put(&nvmem->refcnt, nvmem_device_release);
472}
473EXPORT_SYMBOL_GPL(nvmem_unregister);
474
475static void devm_nvmem_release(struct device *dev, void *res)
476{
477 nvmem_unregister(*(struct nvmem_device **)res);
478}
479
480/**
481 * devm_nvmem_register() - Register a managed nvmem device for given
482 * nvmem_config.
483 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
484 *
485 * @dev: Device that uses the nvmem device.
486 * @config: nvmem device configuration with which nvmem device is created.
487 *
488 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
489 * on success.
490 */
491struct nvmem_device *devm_nvmem_register(struct device *dev,
492 const struct nvmem_config *config)
493{
494 struct nvmem_device **ptr, *nvmem;
495
496 ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
497 if (!ptr)
498 return ERR_PTR(-ENOMEM);
499
500 nvmem = nvmem_register(config);
501
502 if (!IS_ERR(nvmem)) {
503 *ptr = nvmem;
504 devres_add(dev, ptr);
505 } else {
506 devres_free(ptr);
507 }
508
509 return nvmem;
510}
511EXPORT_SYMBOL_GPL(devm_nvmem_register);
512
513static int devm_nvmem_match(struct device *dev, void *res, void *data)
514{
515 struct nvmem_device **r = res;
516
517 return *r == data;
518}
519
520/**
521 * devm_nvmem_unregister() - Unregister previously registered managed nvmem
522 * device.
523 *
524 * @dev: Device that uses the nvmem device.
525 * @nvmem: Pointer to previously registered nvmem device.
526 *
527 * Return: Will be an negative on error or a zero on success.
528 */
529int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
530{
531 return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
532}
533EXPORT_SYMBOL(devm_nvmem_unregister);
534
535static struct nvmem_device *__nvmem_device_get(struct device_node *np,
536 const char *nvmem_name)
537{
538 struct nvmem_device *nvmem = NULL;
539
540 mutex_lock(&nvmem_mutex);
541 nvmem = np ? of_nvmem_find(np) : nvmem_find(nvmem_name);
542 mutex_unlock(&nvmem_mutex);
543 if (!nvmem)
544 return ERR_PTR(-EPROBE_DEFER);
545
546 if (!try_module_get(nvmem->owner)) {
547 dev_err(&nvmem->dev,
548 "could not increase module refcount for cell %s\n",
549 nvmem_dev_name(nvmem));
550
551 put_device(&nvmem->dev);
552 return ERR_PTR(-EINVAL);
553 }
554
555 kref_get(&nvmem->refcnt);
556
557 return nvmem;
558}
559
560static void __nvmem_device_put(struct nvmem_device *nvmem)
561{
562 put_device(&nvmem->dev);
563 module_put(nvmem->owner);
564 kref_put(&nvmem->refcnt, nvmem_device_release);
565}
566
567#if IS_ENABLED(CONFIG_OF)
568/**
569 * of_nvmem_device_get() - Get nvmem device from a given id
570 *
571 * @np: Device tree node that uses the nvmem device.
572 * @id: nvmem name from nvmem-names property.
573 *
574 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
575 * on success.
576 */
577struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
578{
579
580 struct device_node *nvmem_np;
581 int index = 0;
582
583 if (id)
584 index = of_property_match_string(np, "nvmem-names", id);
585
586 nvmem_np = of_parse_phandle(np, "nvmem", index);
587 if (!nvmem_np)
588 return ERR_PTR(-ENOENT);
589
590 return __nvmem_device_get(nvmem_np, NULL);
591}
592EXPORT_SYMBOL_GPL(of_nvmem_device_get);
593#endif
594
595/**
596 * nvmem_device_get() - Get nvmem device from a given id
597 *
598 * @dev: Device that uses the nvmem device.
599 * @dev_name: name of the requested nvmem device.
600 *
601 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
602 * on success.
603 */
604struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
605{
606 if (dev->of_node) { /* try dt first */
607 struct nvmem_device *nvmem;
608
609 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
610
611 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
612 return nvmem;
613
614 }
615
616 return __nvmem_device_get(NULL, dev_name);
617}
618EXPORT_SYMBOL_GPL(nvmem_device_get);
619
620static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
621{
622 struct nvmem_device **nvmem = res;
623
624 if (WARN_ON(!nvmem || !*nvmem))
625 return 0;
626
627 return *nvmem == data;
628}
629
630static void devm_nvmem_device_release(struct device *dev, void *res)
631{
632 nvmem_device_put(*(struct nvmem_device **)res);
633}
634
635/**
636 * devm_nvmem_device_put() - put alredy got nvmem device
637 *
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.
641 */
642void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
643{
644 int ret;
645
646 ret = devres_release(dev, devm_nvmem_device_release,
647 devm_nvmem_device_match, nvmem);
648
649 WARN_ON(ret);
650}
651EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
652
653/**
654 * nvmem_device_put() - put alredy got nvmem device
655 *
656 * @nvmem: pointer to nvmem device that needs to be released.
657 */
658void nvmem_device_put(struct nvmem_device *nvmem)
659{
660 __nvmem_device_put(nvmem);
661}
662EXPORT_SYMBOL_GPL(nvmem_device_put);
663
664/**
665 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
666 *
667 * @dev: Device that requests the nvmem device.
668 * @id: name id for the requested nvmem device.
669 *
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
672 * device is freed.
673 */
674struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
675{
676 struct nvmem_device **ptr, *nvmem;
677
678 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
679 if (!ptr)
680 return ERR_PTR(-ENOMEM);
681
682 nvmem = nvmem_device_get(dev, id);
683 if (!IS_ERR(nvmem)) {
684 *ptr = nvmem;
685 devres_add(dev, ptr);
686 } else {
687 devres_free(ptr);
688 }
689
690 return nvmem;
691}
692EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
693
694static struct nvmem_cell *
695nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
696{
697 struct nvmem_cell *cell = ERR_PTR(-ENOENT);
698 struct nvmem_cell_lookup *lookup;
699 struct nvmem_device *nvmem;
700 const char *dev_id;
701
702 if (!dev)
703 return ERR_PTR(-EINVAL);
704
705 dev_id = dev_name(dev);
706
707 mutex_lock(&nvmem_lookup_mutex);
708
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);
714 if (IS_ERR(nvmem)) {
715 /* Provider may not be registered yet. */
716 cell = ERR_CAST(nvmem);
717 break;
718 }
719
720 cell = nvmem_find_cell_by_name(nvmem,
721 lookup->cell_name);
722 if (!cell) {
723 __nvmem_device_put(nvmem);
724 cell = ERR_PTR(-ENOENT);
725 }
726 break;
727 }
728 }
729
730 mutex_unlock(&nvmem_lookup_mutex);
731 return cell;
732}
733
734#if IS_ENABLED(CONFIG_OF)
735static struct nvmem_cell *
736nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
737{
738 struct nvmem_cell *iter, *cell = NULL;
739
740 mutex_lock(&nvmem_mutex);
741 list_for_each_entry(iter, &nvmem->cells, node) {
742 if (np == iter->np) {
743 cell = iter;
744 break;
745 }
746 }
747 mutex_unlock(&nvmem_mutex);
748
749 return cell;
750}
751
752/**
753 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
754 *
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).
759 *
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
762 * nvmem_cell_put().
763 */
764struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
765{
766 struct device_node *cell_np, *nvmem_np;
767 struct nvmem_device *nvmem;
768 struct nvmem_cell *cell;
769 int index = 0;
770
771 /* if cell name exists, find index to the name */
772 if (id)
773 index = of_property_match_string(np, "nvmem-cell-names", id);
774
775 cell_np = of_parse_phandle(np, "nvmem-cells", index);
776 if (!cell_np)
777 return ERR_PTR(-ENOENT);
778
779 nvmem_np = of_get_next_parent(cell_np);
780 if (!nvmem_np)
781 return ERR_PTR(-EINVAL);
782
783 nvmem = __nvmem_device_get(nvmem_np, NULL);
784 of_node_put(nvmem_np);
785 if (IS_ERR(nvmem))
786 return ERR_CAST(nvmem);
787
788 cell = nvmem_find_cell_by_node(nvmem, cell_np);
789 if (!cell) {
790 __nvmem_device_put(nvmem);
791 return ERR_PTR(-ENOENT);
792 }
793
794 return cell;
795}
796EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
797#endif
798
799/**
800 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
801 *
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).
806 *
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
809 * nvmem_cell_put().
810 */
811struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
812{
813 struct nvmem_cell *cell;
814
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)
818 return cell;
819 }
820
821 /* NULL cell id only allowed for device tree; invalid otherwise */
822 if (!id)
823 return ERR_PTR(-EINVAL);
824
825 return nvmem_cell_get_from_lookup(dev, id);
826}
827EXPORT_SYMBOL_GPL(nvmem_cell_get);
828
829static void devm_nvmem_cell_release(struct device *dev, void *res)
830{
831 nvmem_cell_put(*(struct nvmem_cell **)res);
832}
833
834/**
835 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
836 *
837 * @dev: Device that requests the nvmem cell.
838 * @id: nvmem cell name id to get.
839 *
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.
843 */
844struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
845{
846 struct nvmem_cell **ptr, *cell;
847
848 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
849 if (!ptr)
850 return ERR_PTR(-ENOMEM);
851
852 cell = nvmem_cell_get(dev, id);
853 if (!IS_ERR(cell)) {
854 *ptr = cell;
855 devres_add(dev, ptr);
856 } else {
857 devres_free(ptr);
858 }
859
860 return cell;
861}
862EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
863
864static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
865{
866 struct nvmem_cell **c = res;
867
868 if (WARN_ON(!c || !*c))
869 return 0;
870
871 return *c == data;
872}
873
874/**
875 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
876 * from devm_nvmem_cell_get.
877 *
878 * @dev: Device that requests the nvmem cell.
879 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
880 */
881void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
882{
883 int ret;
884
885 ret = devres_release(dev, devm_nvmem_cell_release,
886 devm_nvmem_cell_match, cell);
887
888 WARN_ON(ret);
889}
890EXPORT_SYMBOL(devm_nvmem_cell_put);
891
892/**
893 * nvmem_cell_put() - Release previously allocated nvmem cell.
894 *
895 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
896 */
897void nvmem_cell_put(struct nvmem_cell *cell)
898{
899 struct nvmem_device *nvmem = cell->nvmem;
900
901 __nvmem_device_put(nvmem);
902}
903EXPORT_SYMBOL_GPL(nvmem_cell_put);
904
905static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
906{
907 u8 *p, *b;
908 int i, extra, bit_offset = cell->bit_offset;
909
910 p = b = buf;
911 if (bit_offset) {
912 /* First shift */
913 *b++ >>= bit_offset;
914
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);
919
920 p = b;
921 *b++ >>= bit_offset;
922 }
923 } else {
924 /* point to the msb */
925 p += cell->bytes - 1;
926 }
927
928 /* result fits in less bytes */
929 extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
930 while (--extra >= 0)
931 *p-- = 0;
932
933 /* clear msb bits if any leftover in the last byte */
934 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
935}
936
937static int __nvmem_cell_read(struct nvmem_device *nvmem,
938 struct nvmem_cell *cell,
939 void *buf, size_t *len)
940{
941 int rc;
942
943 rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
944
945 if (rc)
946 return rc;
947
948 /* shift bits in-place */
949 if (cell->bit_offset || cell->nbits)
950 nvmem_shift_read_buffer_in_place(cell, buf);
951
952 if (len)
953 *len = cell->bytes;
954
955 return 0;
956}
957
958/**
959 * nvmem_cell_read() - Read a given nvmem cell
960 *
961 * @cell: nvmem cell to be read.
962 * @len: pointer to length of cell which will be populated on successful read;
963 * can be NULL.
964 *
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().
967 */
968void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
969{
970 struct nvmem_device *nvmem = cell->nvmem;
971 u8 *buf;
972 int rc;
973
974 if (!nvmem)
975 return ERR_PTR(-EINVAL);
976
977 buf = kzalloc(cell->bytes, GFP_KERNEL);
978 if (!buf)
979 return ERR_PTR(-ENOMEM);
980
981 rc = __nvmem_cell_read(nvmem, cell, buf, len);
982 if (rc) {
983 kfree(buf);
984 return ERR_PTR(rc);
985 }
986
987 return buf;
988}
989EXPORT_SYMBOL_GPL(nvmem_cell_read);
990
991static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
992 u8 *_buf, int len)
993{
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;
997
998 nbits = cell->nbits;
999 buf = kzalloc(cell->bytes, GFP_KERNEL);
1000 if (!buf)
1001 return ERR_PTR(-ENOMEM);
1002
1003 memcpy(buf, _buf, len);
1004 p = b = buf;
1005
1006 if (bit_offset) {
1007 pbyte = *b;
1008 *b <<= bit_offset;
1009
1010 /* setup the first byte with lsb bits from nvmem */
1011 rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
1012 if (rc)
1013 goto err;
1014 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1015
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);
1020 pbyte = *b;
1021 p = b;
1022 *b <<= bit_offset;
1023 *b++ |= pbits;
1024 }
1025 }
1026
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);
1032 if (rc)
1033 goto err;
1034 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1035
1036 }
1037
1038 return buf;
1039err:
1040 kfree(buf);
1041 return ERR_PTR(rc);
1042}
1043
1044/**
1045 * nvmem_cell_write() - Write to a given nvmem cell
1046 *
1047 * @cell: nvmem cell to be written.
1048 * @buf: Buffer to be written.
1049 * @len: length of buffer to be written to nvmem cell.
1050 *
1051 * Return: length of bytes written or negative on failure.
1052 */
1053int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1054{
1055 struct nvmem_device *nvmem = cell->nvmem;
1056 int rc;
1057
1058 if (!nvmem || nvmem->read_only ||
1059 (cell->bit_offset == 0 && len != cell->bytes))
1060 return -EINVAL;
1061
1062 if (cell->bit_offset || cell->nbits) {
1063 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1064 if (IS_ERR(buf))
1065 return PTR_ERR(buf);
1066 }
1067
1068 rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);
1069
1070 /* free the tmp buffer */
1071 if (cell->bit_offset || cell->nbits)
1072 kfree(buf);
1073
1074 if (rc)
1075 return rc;
1076
1077 return len;
1078}
1079EXPORT_SYMBOL_GPL(nvmem_cell_write);
1080
1081/**
1082 * nvmem_cell_read_u16() - Read a cell value as an u16
1083 *
1084 * @dev: Device that requests the nvmem cell.
1085 * @cell_id: Name of nvmem cell to read.
1086 * @val: pointer to output value.
1087 *
1088 * Return: 0 on success or negative errno.
1089 */
1090int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
1091{
1092 struct nvmem_cell *cell;
1093 void *buf;
1094 size_t len;
1095
1096 cell = nvmem_cell_get(dev, cell_id);
1097 if (IS_ERR(cell))
1098 return PTR_ERR(cell);
1099
1100 buf = nvmem_cell_read(cell, &len);
1101 if (IS_ERR(buf)) {
1102 nvmem_cell_put(cell);
1103 return PTR_ERR(buf);
1104 }
1105 if (len != sizeof(*val)) {
1106 kfree(buf);
1107 nvmem_cell_put(cell);
1108 return -EINVAL;
1109 }
1110 memcpy(val, buf, sizeof(*val));
1111 kfree(buf);
1112 nvmem_cell_put(cell);
1113
1114 return 0;
1115}
1116EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);
1117
1118/**
1119 * nvmem_cell_read_u32() - Read a cell value as an u32
1120 *
1121 * @dev: Device that requests the nvmem cell.
1122 * @cell_id: Name of nvmem cell to read.
1123 * @val: pointer to output value.
1124 *
1125 * Return: 0 on success or negative errno.
1126 */
1127int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
1128{
1129 struct nvmem_cell *cell;
1130 void *buf;
1131 size_t len;
1132
1133 cell = nvmem_cell_get(dev, cell_id);
1134 if (IS_ERR(cell))
1135 return PTR_ERR(cell);
1136
1137 buf = nvmem_cell_read(cell, &len);
1138 if (IS_ERR(buf)) {
1139 nvmem_cell_put(cell);
1140 return PTR_ERR(buf);
1141 }
1142 if (len != sizeof(*val)) {
1143 kfree(buf);
1144 nvmem_cell_put(cell);
1145 return -EINVAL;
1146 }
1147 memcpy(val, buf, sizeof(*val));
1148
1149 kfree(buf);
1150 nvmem_cell_put(cell);
1151 return 0;
1152}
1153EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);
1154
1155/**
1156 * nvmem_device_cell_read() - Read a given nvmem device and cell
1157 *
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.
1161 *
1162 * Return: length of successful bytes read on success and negative
1163 * error code on error.
1164 */
1165ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1166 struct nvmem_cell_info *info, void *buf)
1167{
1168 struct nvmem_cell cell;
1169 int rc;
1170 ssize_t len;
1171
1172 if (!nvmem)
1173 return -EINVAL;
1174
1175 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1176 if (rc)
1177 return rc;
1178
1179 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1180 if (rc)
1181 return rc;
1182
1183 return len;
1184}
1185EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1186
1187/**
1188 * nvmem_device_cell_write() - Write cell to a given nvmem device
1189 *
1190 * @nvmem: nvmem device to be written to.
1191 * @info: nvmem cell info to be written.
1192 * @buf: buffer to be written to cell.
1193 *
1194 * Return: length of bytes written or negative error code on failure.
1195 */
1196int nvmem_device_cell_write(struct nvmem_device *nvmem,
1197 struct nvmem_cell_info *info, void *buf)
1198{
1199 struct nvmem_cell cell;
1200 int rc;
1201
1202 if (!nvmem)
1203 return -EINVAL;
1204
1205 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1206 if (rc)
1207 return rc;
1208
1209 return nvmem_cell_write(&cell, buf, cell.bytes);
1210}
1211EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1212
1213/**
1214 * nvmem_device_read() - Read from a given nvmem device
1215 *
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.
1220 *
1221 * Return: length of successful bytes read on success and negative
1222 * error code on error.
1223 */
1224int nvmem_device_read(struct nvmem_device *nvmem,
1225 unsigned int offset,
1226 size_t bytes, void *buf)
1227{
1228 int rc;
1229
1230 if (!nvmem)
1231 return -EINVAL;
1232
1233 rc = nvmem_reg_read(nvmem, offset, buf, bytes);
1234
1235 if (rc)
1236 return rc;
1237
1238 return bytes;
1239}
1240EXPORT_SYMBOL_GPL(nvmem_device_read);
1241
1242/**
1243 * nvmem_device_write() - Write cell to a given nvmem device
1244 *
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.
1249 *
1250 * Return: length of bytes written or negative error code on failure.
1251 */
1252int nvmem_device_write(struct nvmem_device *nvmem,
1253 unsigned int offset,
1254 size_t bytes, void *buf)
1255{
1256 int rc;
1257
1258 if (!nvmem)
1259 return -EINVAL;
1260
1261 rc = nvmem_reg_write(nvmem, offset, buf, bytes);
1262
1263 if (rc)
1264 return rc;
1265
1266
1267 return bytes;
1268}
1269EXPORT_SYMBOL_GPL(nvmem_device_write);
1270
1271/**
1272 * nvmem_add_cell_table() - register a table of cell info entries
1273 *
1274 * @table: table of cell info entries
1275 */
1276void nvmem_add_cell_table(struct nvmem_cell_table *table)
1277{
1278 mutex_lock(&nvmem_cell_mutex);
1279 list_add_tail(&table->node, &nvmem_cell_tables);
1280 mutex_unlock(&nvmem_cell_mutex);
1281}
1282EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
1283
1284/**
1285 * nvmem_del_cell_table() - remove a previously registered cell info table
1286 *
1287 * @table: table of cell info entries
1288 */
1289void nvmem_del_cell_table(struct nvmem_cell_table *table)
1290{
1291 mutex_lock(&nvmem_cell_mutex);
1292 list_del(&table->node);
1293 mutex_unlock(&nvmem_cell_mutex);
1294}
1295EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
1296
1297/**
1298 * nvmem_add_cell_lookups() - register a list of cell lookup entries
1299 *
1300 * @entries: array of cell lookup entries
1301 * @nentries: number of cell lookup entries in the array
1302 */
1303void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1304{
1305 int i;
1306
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);
1311}
1312EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);
1313
1314/**
1315 * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
1316 * entries
1317 *
1318 * @entries: array of cell lookup entries
1319 * @nentries: number of cell lookup entries in the array
1320 */
1321void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
1322{
1323 int i;
1324
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);
1329}
1330EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);
1331
1332/**
1333 * nvmem_dev_name() - Get the name of a given nvmem device.
1334 *
1335 * @nvmem: nvmem device.
1336 *
1337 * Return: name of the nvmem device.
1338 */
1339const char *nvmem_dev_name(struct nvmem_device *nvmem)
1340{
1341 return dev_name(&nvmem->dev);
1342}
1343EXPORT_SYMBOL_GPL(nvmem_dev_name);
1344
1345static int __init nvmem_init(void)
1346{
1347 return bus_register(&nvmem_bus_type);
1348}
1349
1350static void __exit nvmem_exit(void)
1351{
1352 bus_unregister(&nvmem_bus_type);
1353}
1354
1355subsys_initcall(nvmem_init);
1356module_exit(nvmem_exit);
1357
1358MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1359MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1360MODULE_DESCRIPTION("nvmem Driver Core");
1361MODULE_LICENSE("GPL v2");