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nvmem: Add backwards compatibility support for older EEPROM drivers.
[linux/fpc-iii.git] / drivers / nvmem / core.c
blob0de3d878c4393b4738d510808e5e667f8d8264c5
1 /*
2 * nvmem framework core.
3 *
4 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
5 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
6 *
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.
10 *
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.
15 */
16
17 #include <linux/device.h>
18 #include <linux/export.h>
19 #include <linux/fs.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>
25 #include <linux/of.h>
26 #include <linux/regmap.h>
27 #include <linux/slab.h>
28
29 struct nvmem_device {
30 const char *name;
31 struct regmap *regmap;
32 struct module *owner;
33 struct device dev;
34 int stride;
35 int word_size;
36 int ncells;
37 int id;
38 int users;
39 size_t size;
40 bool read_only;
41 int flags;
42 struct bin_attribute eeprom;
43 struct device *base_dev;
44 };
45
46 #define FLAG_COMPAT BIT(0)
47
48 struct nvmem_cell {
49 const char *name;
50 int offset;
51 int bytes;
52 int bit_offset;
53 int nbits;
54 struct nvmem_device *nvmem;
55 struct list_head node;
56 };
57
58 static DEFINE_MUTEX(nvmem_mutex);
59 static DEFINE_IDA(nvmem_ida);
60
61 static LIST_HEAD(nvmem_cells);
62 static DEFINE_MUTEX(nvmem_cells_mutex);
63
64 #ifdef CONFIG_DEBUG_LOCK_ALLOC
65 static struct lock_class_key eeprom_lock_key;
66 #endif
67
68 #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
69
70 static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
71 struct bin_attribute *attr,
72 char *buf, loff_t pos, size_t count)
73 {
74 struct device *dev;
75 struct nvmem_device *nvmem;
76 int rc;
77
78 if (attr->private)
79 dev = attr->private;
80 else
81 dev = container_of(kobj, struct device, kobj);
82 nvmem = to_nvmem_device(dev);
83
84 /* Stop the user from reading */
85 if (pos >= nvmem->size)
86 return 0;
87
88 if (count < nvmem->word_size)
89 return -EINVAL;
90
91 if (pos + count > nvmem->size)
92 count = nvmem->size - pos;
93
94 count = round_down(count, nvmem->word_size);
95
96 rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
97
98 if (IS_ERR_VALUE(rc))
99 return rc;
100
101 return count;
102 }
103
104 static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
105 struct bin_attribute *attr,
106 char *buf, loff_t pos, size_t count)
107 {
108 struct device *dev;
109 struct nvmem_device *nvmem;
110 int rc;
111
112 if (attr->private)
113 dev = attr->private;
114 else
115 dev = container_of(kobj, struct device, kobj);
116 nvmem = to_nvmem_device(dev);
117
118 /* Stop the user from writing */
119 if (pos >= nvmem->size)
120 return 0;
121
122 if (count < nvmem->word_size)
123 return -EINVAL;
124
125 if (pos + count > nvmem->size)
126 count = nvmem->size - pos;
127
128 count = round_down(count, nvmem->word_size);
129
130 rc = regmap_raw_write(nvmem->regmap, pos, buf, count);
131
132 if (IS_ERR_VALUE(rc))
133 return rc;
134
135 return count;
136 }
137
138 /* default read/write permissions */
139 static struct bin_attribute bin_attr_rw_nvmem = {
140 .attr = {
141 .name = "nvmem",
142 .mode = S_IWUSR | S_IRUGO,
143 },
144 .read = bin_attr_nvmem_read,
145 .write = bin_attr_nvmem_write,
146 };
147
148 static struct bin_attribute *nvmem_bin_rw_attributes[] = {
149 &bin_attr_rw_nvmem,
150 NULL,
151 };
152
153 static const struct attribute_group nvmem_bin_rw_group = {
154 .bin_attrs = nvmem_bin_rw_attributes,
155 };
156
157 static const struct attribute_group *nvmem_rw_dev_groups[] = {
158 &nvmem_bin_rw_group,
159 NULL,
160 };
161
162 /* read only permission */
163 static struct bin_attribute bin_attr_ro_nvmem = {
164 .attr = {
165 .name = "nvmem",
166 .mode = S_IRUGO,
167 },
168 .read = bin_attr_nvmem_read,
169 };
170
171 static struct bin_attribute *nvmem_bin_ro_attributes[] = {
172 &bin_attr_ro_nvmem,
173 NULL,
174 };
175
176 static const struct attribute_group nvmem_bin_ro_group = {
177 .bin_attrs = nvmem_bin_ro_attributes,
178 };
179
180 static const struct attribute_group *nvmem_ro_dev_groups[] = {
181 &nvmem_bin_ro_group,
182 NULL,
183 };
184
185 /* default read/write permissions, root only */
186 static struct bin_attribute bin_attr_rw_root_nvmem = {
187 .attr = {
188 .name = "nvmem",
189 .mode = S_IWUSR | S_IRUSR,
190 },
191 .read = bin_attr_nvmem_read,
192 .write = bin_attr_nvmem_write,
193 };
194
195 static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
196 &bin_attr_rw_root_nvmem,
197 NULL,
198 };
199
200 static const struct attribute_group nvmem_bin_rw_root_group = {
201 .bin_attrs = nvmem_bin_rw_root_attributes,
202 };
203
204 static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
205 &nvmem_bin_rw_root_group,
206 NULL,
207 };
208
209 /* read only permission, root only */
210 static struct bin_attribute bin_attr_ro_root_nvmem = {
211 .attr = {
212 .name = "nvmem",
213 .mode = S_IRUSR,
214 },
215 .read = bin_attr_nvmem_read,
216 };
217
218 static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
219 &bin_attr_ro_root_nvmem,
220 NULL,
221 };
222
223 static const struct attribute_group nvmem_bin_ro_root_group = {
224 .bin_attrs = nvmem_bin_ro_root_attributes,
225 };
226
227 static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
228 &nvmem_bin_ro_root_group,
229 NULL,
230 };
231
232 static void nvmem_release(struct device *dev)
233 {
234 struct nvmem_device *nvmem = to_nvmem_device(dev);
235
236 ida_simple_remove(&nvmem_ida, nvmem->id);
237 kfree(nvmem);
238 }
239
240 static const struct device_type nvmem_provider_type = {
241 .release = nvmem_release,
242 };
243
244 static struct bus_type nvmem_bus_type = {
245 .name = "nvmem",
246 };
247
248 static int of_nvmem_match(struct device *dev, void *nvmem_np)
249 {
250 return dev->of_node == nvmem_np;
251 }
252
253 static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
254 {
255 struct device *d;
256
257 if (!nvmem_np)
258 return NULL;
259
260 d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
261
262 if (!d)
263 return NULL;
264
265 return to_nvmem_device(d);
266 }
267
268 static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
269 {
270 struct nvmem_cell *p;
271
272 list_for_each_entry(p, &nvmem_cells, node)
273 if (p && !strcmp(p->name, cell_id))
274 return p;
275
276 return NULL;
277 }
278
279 static void nvmem_cell_drop(struct nvmem_cell *cell)
280 {
281 mutex_lock(&nvmem_cells_mutex);
282 list_del(&cell->node);
283 mutex_unlock(&nvmem_cells_mutex);
284 kfree(cell);
285 }
286
287 static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
288 {
289 struct nvmem_cell *cell;
290 struct list_head *p, *n;
291
292 list_for_each_safe(p, n, &nvmem_cells) {
293 cell = list_entry(p, struct nvmem_cell, node);
294 if (cell->nvmem == nvmem)
295 nvmem_cell_drop(cell);
296 }
297 }
298
299 static void nvmem_cell_add(struct nvmem_cell *cell)
300 {
301 mutex_lock(&nvmem_cells_mutex);
302 list_add_tail(&cell->node, &nvmem_cells);
303 mutex_unlock(&nvmem_cells_mutex);
304 }
305
306 static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
307 const struct nvmem_cell_info *info,
308 struct nvmem_cell *cell)
309 {
310 cell->nvmem = nvmem;
311 cell->offset = info->offset;
312 cell->bytes = info->bytes;
313 cell->name = info->name;
314
315 cell->bit_offset = info->bit_offset;
316 cell->nbits = info->nbits;
317
318 if (cell->nbits)
319 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
320 BITS_PER_BYTE);
321
322 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
323 dev_err(&nvmem->dev,
324 "cell %s unaligned to nvmem stride %d\n",
325 cell->name, nvmem->stride);
326 return -EINVAL;
327 }
328
329 return 0;
330 }
331
332 static int nvmem_add_cells(struct nvmem_device *nvmem,
333 const struct nvmem_config *cfg)
334 {
335 struct nvmem_cell **cells;
336 const struct nvmem_cell_info *info = cfg->cells;
337 int i, rval;
338
339 cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
340 if (!cells)
341 return -ENOMEM;
342
343 for (i = 0; i < cfg->ncells; i++) {
344 cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
345 if (!cells[i]) {
346 rval = -ENOMEM;
347 goto err;
348 }
349
350 rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
351 if (IS_ERR_VALUE(rval)) {
352 kfree(cells[i]);
353 goto err;
354 }
355
356 nvmem_cell_add(cells[i]);
357 }
358
359 nvmem->ncells = cfg->ncells;
360 /* remove tmp array */
361 kfree(cells);
362
363 return 0;
364 err:
365 while (i--)
366 nvmem_cell_drop(cells[i]);
367
368 kfree(cells);
369
370 return rval;
371 }
372
373 /*
374 * nvmem_setup_compat() - Create an additional binary entry in
375 * drivers sys directory, to be backwards compatible with the older
376 * drivers/misc/eeprom drivers.
377 */
378 static int nvmem_setup_compat(struct nvmem_device *nvmem,
379 const struct nvmem_config *config)
380 {
381 int rval;
382
383 if (!config->base_dev)
384 return -EINVAL;
385
386 if (nvmem->read_only)
387 nvmem->eeprom = bin_attr_ro_root_nvmem;
388 else
389 nvmem->eeprom = bin_attr_rw_root_nvmem;
390 nvmem->eeprom.attr.name = "eeprom";
391 nvmem->eeprom.size = nvmem->size;
392 #ifdef CONFIG_DEBUG_LOCK_ALLOC
393 nvmem->eeprom.attr.key = &eeprom_lock_key;
394 #endif
395 nvmem->eeprom.private = &nvmem->dev;
396 nvmem->base_dev = config->base_dev;
397
398 rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
399 if (rval) {
400 dev_err(&nvmem->dev,
401 "Failed to create eeprom binary file %d\n", rval);
402 return rval;
403 }
404
405 nvmem->flags |= FLAG_COMPAT;
406
407 return 0;
408 }
409
410 /**
411 * nvmem_register() - Register a nvmem device for given nvmem_config.
412 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
413 *
414 * @config: nvmem device configuration with which nvmem device is created.
415 *
416 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
417 * on success.
418 */
419
420 struct nvmem_device *nvmem_register(const struct nvmem_config *config)
421 {
422 struct nvmem_device *nvmem;
423 struct device_node *np;
424 struct regmap *rm;
425 int rval;
426
427 if (!config->dev)
428 return ERR_PTR(-EINVAL);
429
430 rm = dev_get_regmap(config->dev, NULL);
431 if (!rm) {
432 dev_err(config->dev, "Regmap not found\n");
433 return ERR_PTR(-EINVAL);
434 }
435
436 nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
437 if (!nvmem)
438 return ERR_PTR(-ENOMEM);
439
440 rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
441 if (rval < 0) {
442 kfree(nvmem);
443 return ERR_PTR(rval);
444 }
445
446 nvmem->id = rval;
447 nvmem->regmap = rm;
448 nvmem->owner = config->owner;
449 nvmem->stride = regmap_get_reg_stride(rm);
450 nvmem->word_size = regmap_get_val_bytes(rm);
451 nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
452 nvmem->dev.type = &nvmem_provider_type;
453 nvmem->dev.bus = &nvmem_bus_type;
454 nvmem->dev.parent = config->dev;
455 np = config->dev->of_node;
456 nvmem->dev.of_node = np;
457 dev_set_name(&nvmem->dev, "%s%d",
458 config->name ? : "nvmem", config->id);
459
460 nvmem->read_only = of_property_read_bool(np, "read-only") |
461 config->read_only;
462
463 if (config->root_only)
464 nvmem->dev.groups = nvmem->read_only ?
465 nvmem_ro_root_dev_groups :
466 nvmem_rw_root_dev_groups;
467 else
468 nvmem->dev.groups = nvmem->read_only ?
469 nvmem_ro_dev_groups :
470 nvmem_rw_dev_groups;
471
472 device_initialize(&nvmem->dev);
473
474 dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
475
476 rval = device_add(&nvmem->dev);
477 if (rval)
478 goto out;
479
480 if (config->compat) {
481 rval = nvmem_setup_compat(nvmem, config);
482 if (rval)
483 goto out;
484 }
485
486 if (config->cells)
487 nvmem_add_cells(nvmem, config);
488
489 return nvmem;
490 out:
491 ida_simple_remove(&nvmem_ida, nvmem->id);
492 kfree(nvmem);
493 return ERR_PTR(rval);
494 }
495 EXPORT_SYMBOL_GPL(nvmem_register);
496
497 /**
498 * nvmem_unregister() - Unregister previously registered nvmem device
499 *
500 * @nvmem: Pointer to previously registered nvmem device.
501 *
502 * Return: Will be an negative on error or a zero on success.
503 */
504 int nvmem_unregister(struct nvmem_device *nvmem)
505 {
506 mutex_lock(&nvmem_mutex);
507 if (nvmem->users) {
508 mutex_unlock(&nvmem_mutex);
509 return -EBUSY;
510 }
511 mutex_unlock(&nvmem_mutex);
512
513 if (nvmem->flags & FLAG_COMPAT)
514 device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
515
516 nvmem_device_remove_all_cells(nvmem);
517 device_del(&nvmem->dev);
518
519 return 0;
520 }
521 EXPORT_SYMBOL_GPL(nvmem_unregister);
522
523 static struct nvmem_device *__nvmem_device_get(struct device_node *np,
524 struct nvmem_cell **cellp,
525 const char *cell_id)
526 {
527 struct nvmem_device *nvmem = NULL;
528
529 mutex_lock(&nvmem_mutex);
530
531 if (np) {
532 nvmem = of_nvmem_find(np);
533 if (!nvmem) {
534 mutex_unlock(&nvmem_mutex);
535 return ERR_PTR(-EPROBE_DEFER);
536 }
537 } else {
538 struct nvmem_cell *cell = nvmem_find_cell(cell_id);
539
540 if (cell) {
541 nvmem = cell->nvmem;
542 *cellp = cell;
543 }
544
545 if (!nvmem) {
546 mutex_unlock(&nvmem_mutex);
547 return ERR_PTR(-ENOENT);
548 }
549 }
550
551 nvmem->users++;
552 mutex_unlock(&nvmem_mutex);
553
554 if (!try_module_get(nvmem->owner)) {
555 dev_err(&nvmem->dev,
556 "could not increase module refcount for cell %s\n",
557 nvmem->name);
558
559 mutex_lock(&nvmem_mutex);
560 nvmem->users--;
561 mutex_unlock(&nvmem_mutex);
562
563 return ERR_PTR(-EINVAL);
564 }
565
566 return nvmem;
567 }
568
569 static void __nvmem_device_put(struct nvmem_device *nvmem)
570 {
571 module_put(nvmem->owner);
572 mutex_lock(&nvmem_mutex);
573 nvmem->users--;
574 mutex_unlock(&nvmem_mutex);
575 }
576
577 static int nvmem_match(struct device *dev, void *data)
578 {
579 return !strcmp(dev_name(dev), data);
580 }
581
582 static struct nvmem_device *nvmem_find(const char *name)
583 {
584 struct device *d;
585
586 d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
587
588 if (!d)
589 return NULL;
590
591 return to_nvmem_device(d);
592 }
593
594 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
595 /**
596 * of_nvmem_device_get() - Get nvmem device from a given id
597 *
598 * @dev node: Device tree node that uses the nvmem device
599 * @id: nvmem name from nvmem-names property.
600 *
601 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
602 * on success.
603 */
604 struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
605 {
606
607 struct device_node *nvmem_np;
608 int index;
609
610 index = of_property_match_string(np, "nvmem-names", id);
611
612 nvmem_np = of_parse_phandle(np, "nvmem", index);
613 if (!nvmem_np)
614 return ERR_PTR(-EINVAL);
615
616 return __nvmem_device_get(nvmem_np, NULL, NULL);
617 }
618 EXPORT_SYMBOL_GPL(of_nvmem_device_get);
619 #endif
620
621 /**
622 * nvmem_device_get() - Get nvmem device from a given id
623 *
624 * @dev : Device that uses the nvmem device
625 * @id: nvmem name from nvmem-names property.
626 *
627 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
628 * on success.
629 */
630 struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
631 {
632 if (dev->of_node) { /* try dt first */
633 struct nvmem_device *nvmem;
634
635 nvmem = of_nvmem_device_get(dev->of_node, dev_name);
636
637 if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
638 return nvmem;
639
640 }
641
642 return nvmem_find(dev_name);
643 }
644 EXPORT_SYMBOL_GPL(nvmem_device_get);
645
646 static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
647 {
648 struct nvmem_device **nvmem = res;
649
650 if (WARN_ON(!nvmem || !*nvmem))
651 return 0;
652
653 return *nvmem == data;
654 }
655
656 static void devm_nvmem_device_release(struct device *dev, void *res)
657 {
658 nvmem_device_put(*(struct nvmem_device **)res);
659 }
660
661 /**
662 * devm_nvmem_device_put() - put alredy got nvmem device
663 *
664 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
665 * that needs to be released.
666 */
667 void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
668 {
669 int ret;
670
671 ret = devres_release(dev, devm_nvmem_device_release,
672 devm_nvmem_device_match, nvmem);
673
674 WARN_ON(ret);
675 }
676 EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
677
678 /**
679 * nvmem_device_put() - put alredy got nvmem device
680 *
681 * @nvmem: pointer to nvmem device that needs to be released.
682 */
683 void nvmem_device_put(struct nvmem_device *nvmem)
684 {
685 __nvmem_device_put(nvmem);
686 }
687 EXPORT_SYMBOL_GPL(nvmem_device_put);
688
689 /**
690 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
691 *
692 * @dev node: Device tree node that uses the nvmem cell
693 * @id: nvmem name in nvmems property.
694 *
695 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
696 * on success. The nvmem_cell will be freed by the automatically once the
697 * device is freed.
698 */
699 struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
700 {
701 struct nvmem_device **ptr, *nvmem;
702
703 ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
704 if (!ptr)
705 return ERR_PTR(-ENOMEM);
706
707 nvmem = nvmem_device_get(dev, id);
708 if (!IS_ERR(nvmem)) {
709 *ptr = nvmem;
710 devres_add(dev, ptr);
711 } else {
712 devres_free(ptr);
713 }
714
715 return nvmem;
716 }
717 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
718
719 static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
720 {
721 struct nvmem_cell *cell = NULL;
722 struct nvmem_device *nvmem;
723
724 nvmem = __nvmem_device_get(NULL, &cell, cell_id);
725 if (IS_ERR(nvmem))
726 return ERR_CAST(nvmem);
727
728 return cell;
729 }
730
731 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
732 /**
733 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
734 *
735 * @dev node: Device tree node that uses the nvmem cell
736 * @id: nvmem cell name from nvmem-cell-names property.
737 *
738 * Return: Will be an ERR_PTR() on error or a valid pointer
739 * to a struct nvmem_cell. The nvmem_cell will be freed by the
740 * nvmem_cell_put().
741 */
742 struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
743 const char *name)
744 {
745 struct device_node *cell_np, *nvmem_np;
746 struct nvmem_cell *cell;
747 struct nvmem_device *nvmem;
748 const __be32 *addr;
749 int rval, len, index;
750
751 index = of_property_match_string(np, "nvmem-cell-names", name);
752
753 cell_np = of_parse_phandle(np, "nvmem-cells", index);
754 if (!cell_np)
755 return ERR_PTR(-EINVAL);
756
757 nvmem_np = of_get_next_parent(cell_np);
758 if (!nvmem_np)
759 return ERR_PTR(-EINVAL);
760
761 nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
762 if (IS_ERR(nvmem))
763 return ERR_CAST(nvmem);
764
765 addr = of_get_property(cell_np, "reg", &len);
766 if (!addr || (len < 2 * sizeof(u32))) {
767 dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
768 cell_np->full_name);
769 rval = -EINVAL;
770 goto err_mem;
771 }
772
773 cell = kzalloc(sizeof(*cell), GFP_KERNEL);
774 if (!cell) {
775 rval = -ENOMEM;
776 goto err_mem;
777 }
778
779 cell->nvmem = nvmem;
780 cell->offset = be32_to_cpup(addr++);
781 cell->bytes = be32_to_cpup(addr);
782 cell->name = cell_np->name;
783
784 addr = of_get_property(cell_np, "bits", &len);
785 if (addr && len == (2 * sizeof(u32))) {
786 cell->bit_offset = be32_to_cpup(addr++);
787 cell->nbits = be32_to_cpup(addr);
788 }
789
790 if (cell->nbits)
791 cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
792 BITS_PER_BYTE);
793
794 if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
795 dev_err(&nvmem->dev,
796 "cell %s unaligned to nvmem stride %d\n",
797 cell->name, nvmem->stride);
798 rval = -EINVAL;
799 goto err_sanity;
800 }
801
802 nvmem_cell_add(cell);
803
804 return cell;
805
806 err_sanity:
807 kfree(cell);
808
809 err_mem:
810 __nvmem_device_put(nvmem);
811
812 return ERR_PTR(rval);
813 }
814 EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
815 #endif
816
817 /**
818 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
819 *
820 * @dev node: Device tree node that uses the nvmem cell
821 * @id: nvmem cell name to get.
822 *
823 * Return: Will be an ERR_PTR() on error or a valid pointer
824 * to a struct nvmem_cell. The nvmem_cell will be freed by the
825 * nvmem_cell_put().
826 */
827 struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
828 {
829 struct nvmem_cell *cell;
830
831 if (dev->of_node) { /* try dt first */
832 cell = of_nvmem_cell_get(dev->of_node, cell_id);
833 if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
834 return cell;
835 }
836
837 return nvmem_cell_get_from_list(cell_id);
838 }
839 EXPORT_SYMBOL_GPL(nvmem_cell_get);
840
841 static void devm_nvmem_cell_release(struct device *dev, void *res)
842 {
843 nvmem_cell_put(*(struct nvmem_cell **)res);
844 }
845
846 /**
847 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
848 *
849 * @dev node: Device tree node that uses the nvmem cell
850 * @id: nvmem id in nvmem-names property.
851 *
852 * Return: Will be an ERR_PTR() on error or a valid pointer
853 * to a struct nvmem_cell. The nvmem_cell will be freed by the
854 * automatically once the device is freed.
855 */
856 struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
857 {
858 struct nvmem_cell **ptr, *cell;
859
860 ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
861 if (!ptr)
862 return ERR_PTR(-ENOMEM);
863
864 cell = nvmem_cell_get(dev, id);
865 if (!IS_ERR(cell)) {
866 *ptr = cell;
867 devres_add(dev, ptr);
868 } else {
869 devres_free(ptr);
870 }
871
872 return cell;
873 }
874 EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
875
876 static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
877 {
878 struct nvmem_cell **c = res;
879
880 if (WARN_ON(!c || !*c))
881 return 0;
882
883 return *c == data;
884 }
885
886 /**
887 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
888 * from devm_nvmem_cell_get.
889 *
890 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
891 */
892 void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
893 {
894 int ret;
895
896 ret = devres_release(dev, devm_nvmem_cell_release,
897 devm_nvmem_cell_match, cell);
898
899 WARN_ON(ret);
900 }
901 EXPORT_SYMBOL(devm_nvmem_cell_put);
902
903 /**
904 * nvmem_cell_put() - Release previously allocated nvmem cell.
905 *
906 * @cell: Previously allocated nvmem cell by nvmem_cell_get()
907 */
908 void nvmem_cell_put(struct nvmem_cell *cell)
909 {
910 struct nvmem_device *nvmem = cell->nvmem;
911
912 __nvmem_device_put(nvmem);
913 nvmem_cell_drop(cell);
914 }
915 EXPORT_SYMBOL_GPL(nvmem_cell_put);
916
917 static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
918 void *buf)
919 {
920 u8 *p, *b;
921 int i, bit_offset = cell->bit_offset;
922
923 p = b = buf;
924 if (bit_offset) {
925 /* First shift */
926 *b++ >>= bit_offset;
927
928 /* setup rest of the bytes if any */
929 for (i = 1; i < cell->bytes; i++) {
930 /* Get bits from next byte and shift them towards msb */
931 *p |= *b << (BITS_PER_BYTE - bit_offset);
932
933 p = b;
934 *b++ >>= bit_offset;
935 }
936
937 /* result fits in less bytes */
938 if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
939 *p-- = 0;
940 }
941 /* clear msb bits if any leftover in the last byte */
942 *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
943 }
944
945 static int __nvmem_cell_read(struct nvmem_device *nvmem,
946 struct nvmem_cell *cell,
947 void *buf, size_t *len)
948 {
949 int rc;
950
951 rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
952
953 if (IS_ERR_VALUE(rc))
954 return rc;
955
956 /* shift bits in-place */
957 if (cell->bit_offset || cell->nbits)
958 nvmem_shift_read_buffer_in_place(cell, buf);
959
960 *len = cell->bytes;
961
962 return 0;
963 }
964
965 /**
966 * nvmem_cell_read() - Read a given nvmem cell
967 *
968 * @cell: nvmem cell to be read.
969 * @len: pointer to length of cell which will be populated on successful read.
970 *
971 * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
972 * The buffer should be freed by the consumer with a kfree().
973 */
974 void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
975 {
976 struct nvmem_device *nvmem = cell->nvmem;
977 u8 *buf;
978 int rc;
979
980 if (!nvmem || !nvmem->regmap)
981 return ERR_PTR(-EINVAL);
982
983 buf = kzalloc(cell->bytes, GFP_KERNEL);
984 if (!buf)
985 return ERR_PTR(-ENOMEM);
986
987 rc = __nvmem_cell_read(nvmem, cell, buf, len);
988 if (IS_ERR_VALUE(rc)) {
989 kfree(buf);
990 return ERR_PTR(rc);
991 }
992
993 return buf;
994 }
995 EXPORT_SYMBOL_GPL(nvmem_cell_read);
996
997 static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
998 u8 *_buf, int len)
999 {
1000 struct nvmem_device *nvmem = cell->nvmem;
1001 int i, rc, nbits, bit_offset = cell->bit_offset;
1002 u8 v, *p, *buf, *b, pbyte, pbits;
1003
1004 nbits = cell->nbits;
1005 buf = kzalloc(cell->bytes, GFP_KERNEL);
1006 if (!buf)
1007 return ERR_PTR(-ENOMEM);
1008
1009 memcpy(buf, _buf, len);
1010 p = b = buf;
1011
1012 if (bit_offset) {
1013 pbyte = *b;
1014 *b <<= bit_offset;
1015
1016 /* setup the first byte with lsb bits from nvmem */
1017 rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
1018 *b++ |= GENMASK(bit_offset - 1, 0) & v;
1019
1020 /* setup rest of the byte if any */
1021 for (i = 1; i < cell->bytes; i++) {
1022 /* Get last byte bits and shift them towards lsb */
1023 pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
1024 pbyte = *b;
1025 p = b;
1026 *b <<= bit_offset;
1027 *b++ |= pbits;
1028 }
1029 }
1030
1031 /* if it's not end on byte boundary */
1032 if ((nbits + bit_offset) % BITS_PER_BYTE) {
1033 /* setup the last byte with msb bits from nvmem */
1034 rc = regmap_raw_read(nvmem->regmap,
1035 cell->offset + cell->bytes - 1, &v, 1);
1036 *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
1037
1038 }
1039
1040 return buf;
1041 }
1042
1043 /**
1044 * nvmem_cell_write() - Write to a given nvmem cell
1045 *
1046 * @cell: nvmem cell to be written.
1047 * @buf: Buffer to be written.
1048 * @len: length of buffer to be written to nvmem cell.
1049 *
1050 * Return: length of bytes written or negative on failure.
1051 */
1052 int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
1053 {
1054 struct nvmem_device *nvmem = cell->nvmem;
1055 int rc;
1056
1057 if (!nvmem || !nvmem->regmap || nvmem->read_only ||
1058 (cell->bit_offset == 0 && len != cell->bytes))
1059 return -EINVAL;
1060
1061 if (cell->bit_offset || cell->nbits) {
1062 buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
1063 if (IS_ERR(buf))
1064 return PTR_ERR(buf);
1065 }
1066
1067 rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);
1068
1069 /* free the tmp buffer */
1070 if (cell->bit_offset || cell->nbits)
1071 kfree(buf);
1072
1073 if (IS_ERR_VALUE(rc))
1074 return rc;
1075
1076 return len;
1077 }
1078 EXPORT_SYMBOL_GPL(nvmem_cell_write);
1079
1080 /**
1081 * nvmem_device_cell_read() - Read a given nvmem device and cell
1082 *
1083 * @nvmem: nvmem device to read from.
1084 * @info: nvmem cell info to be read.
1085 * @buf: buffer pointer which will be populated on successful read.
1086 *
1087 * Return: length of successful bytes read on success and negative
1088 * error code on error.
1089 */
1090 ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
1091 struct nvmem_cell_info *info, void *buf)
1092 {
1093 struct nvmem_cell cell;
1094 int rc;
1095 ssize_t len;
1096
1097 if (!nvmem || !nvmem->regmap)
1098 return -EINVAL;
1099
1100 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1101 if (IS_ERR_VALUE(rc))
1102 return rc;
1103
1104 rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
1105 if (IS_ERR_VALUE(rc))
1106 return rc;
1107
1108 return len;
1109 }
1110 EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
1111
1112 /**
1113 * nvmem_device_cell_write() - Write cell to a given nvmem device
1114 *
1115 * @nvmem: nvmem device to be written to.
1116 * @info: nvmem cell info to be written
1117 * @buf: buffer to be written to cell.
1118 *
1119 * Return: length of bytes written or negative error code on failure.
1120 * */
1121 int nvmem_device_cell_write(struct nvmem_device *nvmem,
1122 struct nvmem_cell_info *info, void *buf)
1123 {
1124 struct nvmem_cell cell;
1125 int rc;
1126
1127 if (!nvmem || !nvmem->regmap)
1128 return -EINVAL;
1129
1130 rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
1131 if (IS_ERR_VALUE(rc))
1132 return rc;
1133
1134 return nvmem_cell_write(&cell, buf, cell.bytes);
1135 }
1136 EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
1137
1138 /**
1139 * nvmem_device_read() - Read from a given nvmem device
1140 *
1141 * @nvmem: nvmem device to read from.
1142 * @offset: offset in nvmem device.
1143 * @bytes: number of bytes to read.
1144 * @buf: buffer pointer which will be populated on successful read.
1145 *
1146 * Return: length of successful bytes read on success and negative
1147 * error code on error.
1148 */
1149 int nvmem_device_read(struct nvmem_device *nvmem,
1150 unsigned int offset,
1151 size_t bytes, void *buf)
1152 {
1153 int rc;
1154
1155 if (!nvmem || !nvmem->regmap)
1156 return -EINVAL;
1157
1158 rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);
1159
1160 if (IS_ERR_VALUE(rc))
1161 return rc;
1162
1163 return bytes;
1164 }
1165 EXPORT_SYMBOL_GPL(nvmem_device_read);
1166
1167 /**
1168 * nvmem_device_write() - Write cell to a given nvmem device
1169 *
1170 * @nvmem: nvmem device to be written to.
1171 * @offset: offset in nvmem device.
1172 * @bytes: number of bytes to write.
1173 * @buf: buffer to be written.
1174 *
1175 * Return: length of bytes written or negative error code on failure.
1176 * */
1177 int nvmem_device_write(struct nvmem_device *nvmem,
1178 unsigned int offset,
1179 size_t bytes, void *buf)
1180 {
1181 int rc;
1182
1183 if (!nvmem || !nvmem->regmap)
1184 return -EINVAL;
1185
1186 rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);
1187
1188 if (IS_ERR_VALUE(rc))
1189 return rc;
1190
1191
1192 return bytes;
1193 }
1194 EXPORT_SYMBOL_GPL(nvmem_device_write);
1195
1196 static int __init nvmem_init(void)
1197 {
1198 return bus_register(&nvmem_bus_type);
1199 }
1200
1201 static void __exit nvmem_exit(void)
1202 {
1203 bus_unregister(&nvmem_bus_type);
1204 }
1205
1206 subsys_initcall(nvmem_init);
1207 module_exit(nvmem_exit);
1208
1209 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
1210 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
1211 MODULE_DESCRIPTION("nvmem Driver Core");
1212 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support