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eace75cf SK |
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> | |
eace75cf SK |
26 | #include <linux/slab.h> |
27 | ||
28 | struct nvmem_device { | |
29 | const char *name; | |
eace75cf SK |
30 | struct module *owner; |
31 | struct device dev; | |
32 | int stride; | |
33 | int word_size; | |
34 | int ncells; | |
35 | int id; | |
36 | int users; | |
37 | size_t size; | |
38 | bool read_only; | |
b6c217ab AL |
39 | int flags; |
40 | struct bin_attribute eeprom; | |
41 | struct device *base_dev; | |
795ddd18 SK |
42 | nvmem_reg_read_t reg_read; |
43 | nvmem_reg_write_t reg_write; | |
44 | void *priv; | |
eace75cf SK |
45 | }; |
46 | ||
b6c217ab AL |
47 | #define FLAG_COMPAT BIT(0) |
48 | ||
eace75cf SK |
49 | struct nvmem_cell { |
50 | const char *name; | |
51 | int offset; | |
52 | int bytes; | |
53 | int bit_offset; | |
54 | int nbits; | |
55 | struct nvmem_device *nvmem; | |
56 | struct list_head node; | |
57 | }; | |
58 | ||
59 | static DEFINE_MUTEX(nvmem_mutex); | |
60 | static DEFINE_IDA(nvmem_ida); | |
61 | ||
62 | static LIST_HEAD(nvmem_cells); | |
63 | static DEFINE_MUTEX(nvmem_cells_mutex); | |
64 | ||
b6c217ab AL |
65 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
66 | static struct lock_class_key eeprom_lock_key; | |
67 | #endif | |
68 | ||
eace75cf | 69 | #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev) |
795ddd18 SK |
70 | static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, |
71 | void *val, size_t bytes) | |
72 | { | |
73 | if (nvmem->reg_read) | |
74 | return nvmem->reg_read(nvmem->priv, offset, val, bytes); | |
75 | ||
76 | return -EINVAL; | |
77 | } | |
78 | ||
79 | static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, | |
80 | void *val, size_t bytes) | |
81 | { | |
82 | if (nvmem->reg_write) | |
83 | return nvmem->reg_write(nvmem->priv, offset, val, bytes); | |
84 | ||
85 | return -EINVAL; | |
86 | } | |
eace75cf SK |
87 | |
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) | |
91 | { | |
b6c217ab AL |
92 | struct device *dev; |
93 | struct nvmem_device *nvmem; | |
eace75cf SK |
94 | int rc; |
95 | ||
b6c217ab AL |
96 | if (attr->private) |
97 | dev = attr->private; | |
98 | else | |
99 | dev = container_of(kobj, struct device, kobj); | |
100 | nvmem = to_nvmem_device(dev); | |
101 | ||
eace75cf | 102 | /* Stop the user from reading */ |
7c806883 | 103 | if (pos >= nvmem->size) |
eace75cf SK |
104 | return 0; |
105 | ||
313a72ff SK |
106 | if (count < nvmem->word_size) |
107 | return -EINVAL; | |
108 | ||
eace75cf SK |
109 | if (pos + count > nvmem->size) |
110 | count = nvmem->size - pos; | |
111 | ||
112 | count = round_down(count, nvmem->word_size); | |
113 | ||
795ddd18 | 114 | rc = nvmem_reg_read(nvmem, pos, buf, count); |
eace75cf | 115 | |
287980e4 | 116 | if (rc) |
eace75cf SK |
117 | return rc; |
118 | ||
119 | return count; | |
120 | } | |
121 | ||
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) | |
125 | { | |
b6c217ab AL |
126 | struct device *dev; |
127 | struct nvmem_device *nvmem; | |
eace75cf SK |
128 | int rc; |
129 | ||
b6c217ab AL |
130 | if (attr->private) |
131 | dev = attr->private; | |
132 | else | |
133 | dev = container_of(kobj, struct device, kobj); | |
134 | nvmem = to_nvmem_device(dev); | |
135 | ||
eace75cf | 136 | /* Stop the user from writing */ |
7c806883 | 137 | if (pos >= nvmem->size) |
eace75cf SK |
138 | return 0; |
139 | ||
313a72ff SK |
140 | if (count < nvmem->word_size) |
141 | return -EINVAL; | |
142 | ||
eace75cf SK |
143 | if (pos + count > nvmem->size) |
144 | count = nvmem->size - pos; | |
145 | ||
146 | count = round_down(count, nvmem->word_size); | |
147 | ||
795ddd18 | 148 | rc = nvmem_reg_write(nvmem, pos, buf, count); |
eace75cf | 149 | |
287980e4 | 150 | if (rc) |
eace75cf SK |
151 | return rc; |
152 | ||
153 | return count; | |
154 | } | |
155 | ||
156 | /* default read/write permissions */ | |
157 | static struct bin_attribute bin_attr_rw_nvmem = { | |
158 | .attr = { | |
159 | .name = "nvmem", | |
160 | .mode = S_IWUSR | S_IRUGO, | |
161 | }, | |
162 | .read = bin_attr_nvmem_read, | |
163 | .write = bin_attr_nvmem_write, | |
164 | }; | |
165 | ||
166 | static struct bin_attribute *nvmem_bin_rw_attributes[] = { | |
167 | &bin_attr_rw_nvmem, | |
168 | NULL, | |
169 | }; | |
170 | ||
171 | static const struct attribute_group nvmem_bin_rw_group = { | |
172 | .bin_attrs = nvmem_bin_rw_attributes, | |
173 | }; | |
174 | ||
175 | static const struct attribute_group *nvmem_rw_dev_groups[] = { | |
176 | &nvmem_bin_rw_group, | |
177 | NULL, | |
178 | }; | |
179 | ||
180 | /* read only permission */ | |
181 | static struct bin_attribute bin_attr_ro_nvmem = { | |
182 | .attr = { | |
183 | .name = "nvmem", | |
184 | .mode = S_IRUGO, | |
185 | }, | |
186 | .read = bin_attr_nvmem_read, | |
187 | }; | |
188 | ||
189 | static struct bin_attribute *nvmem_bin_ro_attributes[] = { | |
190 | &bin_attr_ro_nvmem, | |
191 | NULL, | |
192 | }; | |
193 | ||
194 | static const struct attribute_group nvmem_bin_ro_group = { | |
195 | .bin_attrs = nvmem_bin_ro_attributes, | |
196 | }; | |
197 | ||
198 | static const struct attribute_group *nvmem_ro_dev_groups[] = { | |
199 | &nvmem_bin_ro_group, | |
200 | NULL, | |
201 | }; | |
202 | ||
811b0d65 AL |
203 | /* default read/write permissions, root only */ |
204 | static struct bin_attribute bin_attr_rw_root_nvmem = { | |
205 | .attr = { | |
206 | .name = "nvmem", | |
207 | .mode = S_IWUSR | S_IRUSR, | |
208 | }, | |
209 | .read = bin_attr_nvmem_read, | |
210 | .write = bin_attr_nvmem_write, | |
211 | }; | |
212 | ||
213 | static struct bin_attribute *nvmem_bin_rw_root_attributes[] = { | |
214 | &bin_attr_rw_root_nvmem, | |
215 | NULL, | |
216 | }; | |
217 | ||
218 | static const struct attribute_group nvmem_bin_rw_root_group = { | |
219 | .bin_attrs = nvmem_bin_rw_root_attributes, | |
220 | }; | |
221 | ||
222 | static const struct attribute_group *nvmem_rw_root_dev_groups[] = { | |
223 | &nvmem_bin_rw_root_group, | |
224 | NULL, | |
225 | }; | |
226 | ||
227 | /* read only permission, root only */ | |
228 | static struct bin_attribute bin_attr_ro_root_nvmem = { | |
229 | .attr = { | |
230 | .name = "nvmem", | |
231 | .mode = S_IRUSR, | |
232 | }, | |
233 | .read = bin_attr_nvmem_read, | |
234 | }; | |
235 | ||
236 | static struct bin_attribute *nvmem_bin_ro_root_attributes[] = { | |
237 | &bin_attr_ro_root_nvmem, | |
238 | NULL, | |
239 | }; | |
240 | ||
241 | static const struct attribute_group nvmem_bin_ro_root_group = { | |
242 | .bin_attrs = nvmem_bin_ro_root_attributes, | |
243 | }; | |
244 | ||
245 | static const struct attribute_group *nvmem_ro_root_dev_groups[] = { | |
246 | &nvmem_bin_ro_root_group, | |
247 | NULL, | |
248 | }; | |
249 | ||
eace75cf SK |
250 | static void nvmem_release(struct device *dev) |
251 | { | |
252 | struct nvmem_device *nvmem = to_nvmem_device(dev); | |
253 | ||
254 | ida_simple_remove(&nvmem_ida, nvmem->id); | |
255 | kfree(nvmem); | |
256 | } | |
257 | ||
258 | static const struct device_type nvmem_provider_type = { | |
259 | .release = nvmem_release, | |
260 | }; | |
261 | ||
262 | static struct bus_type nvmem_bus_type = { | |
263 | .name = "nvmem", | |
264 | }; | |
265 | ||
266 | static int of_nvmem_match(struct device *dev, void *nvmem_np) | |
267 | { | |
268 | return dev->of_node == nvmem_np; | |
269 | } | |
270 | ||
271 | static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np) | |
272 | { | |
273 | struct device *d; | |
274 | ||
275 | if (!nvmem_np) | |
276 | return NULL; | |
277 | ||
278 | d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match); | |
279 | ||
280 | if (!d) | |
281 | return NULL; | |
282 | ||
283 | return to_nvmem_device(d); | |
284 | } | |
285 | ||
286 | static struct nvmem_cell *nvmem_find_cell(const char *cell_id) | |
287 | { | |
288 | struct nvmem_cell *p; | |
289 | ||
290 | list_for_each_entry(p, &nvmem_cells, node) | |
291 | if (p && !strcmp(p->name, cell_id)) | |
292 | return p; | |
293 | ||
294 | return NULL; | |
295 | } | |
296 | ||
297 | static void nvmem_cell_drop(struct nvmem_cell *cell) | |
298 | { | |
299 | mutex_lock(&nvmem_cells_mutex); | |
300 | list_del(&cell->node); | |
301 | mutex_unlock(&nvmem_cells_mutex); | |
302 | kfree(cell); | |
303 | } | |
304 | ||
305 | static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem) | |
306 | { | |
307 | struct nvmem_cell *cell; | |
308 | struct list_head *p, *n; | |
309 | ||
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); | |
314 | } | |
315 | } | |
316 | ||
317 | static void nvmem_cell_add(struct nvmem_cell *cell) | |
318 | { | |
319 | mutex_lock(&nvmem_cells_mutex); | |
320 | list_add_tail(&cell->node, &nvmem_cells); | |
321 | mutex_unlock(&nvmem_cells_mutex); | |
322 | } | |
323 | ||
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) | |
327 | { | |
328 | cell->nvmem = nvmem; | |
329 | cell->offset = info->offset; | |
330 | cell->bytes = info->bytes; | |
331 | cell->name = info->name; | |
332 | ||
333 | cell->bit_offset = info->bit_offset; | |
334 | cell->nbits = info->nbits; | |
335 | ||
336 | if (cell->nbits) | |
337 | cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset, | |
338 | BITS_PER_BYTE); | |
339 | ||
340 | if (!IS_ALIGNED(cell->offset, nvmem->stride)) { | |
341 | dev_err(&nvmem->dev, | |
342 | "cell %s unaligned to nvmem stride %d\n", | |
343 | cell->name, nvmem->stride); | |
344 | return -EINVAL; | |
345 | } | |
346 | ||
347 | return 0; | |
348 | } | |
349 | ||
350 | static int nvmem_add_cells(struct nvmem_device *nvmem, | |
351 | const struct nvmem_config *cfg) | |
352 | { | |
353 | struct nvmem_cell **cells; | |
354 | const struct nvmem_cell_info *info = cfg->cells; | |
355 | int i, rval; | |
356 | ||
357 | cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL); | |
358 | if (!cells) | |
359 | return -ENOMEM; | |
360 | ||
361 | for (i = 0; i < cfg->ncells; i++) { | |
362 | cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL); | |
363 | if (!cells[i]) { | |
364 | rval = -ENOMEM; | |
365 | goto err; | |
366 | } | |
367 | ||
368 | rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]); | |
287980e4 | 369 | if (rval) { |
eace75cf SK |
370 | kfree(cells[i]); |
371 | goto err; | |
372 | } | |
373 | ||
374 | nvmem_cell_add(cells[i]); | |
375 | } | |
376 | ||
377 | nvmem->ncells = cfg->ncells; | |
378 | /* remove tmp array */ | |
379 | kfree(cells); | |
380 | ||
381 | return 0; | |
382 | err: | |
dfdf1414 | 383 | while (i--) |
eace75cf SK |
384 | nvmem_cell_drop(cells[i]); |
385 | ||
dfdf1414 RV |
386 | kfree(cells); |
387 | ||
eace75cf SK |
388 | return rval; |
389 | } | |
390 | ||
b6c217ab AL |
391 | /* |
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. | |
395 | */ | |
396 | static int nvmem_setup_compat(struct nvmem_device *nvmem, | |
397 | const struct nvmem_config *config) | |
398 | { | |
399 | int rval; | |
400 | ||
401 | if (!config->base_dev) | |
402 | return -EINVAL; | |
403 | ||
404 | if (nvmem->read_only) | |
405 | nvmem->eeprom = bin_attr_ro_root_nvmem; | |
406 | else | |
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; | |
412 | #endif | |
413 | nvmem->eeprom.private = &nvmem->dev; | |
414 | nvmem->base_dev = config->base_dev; | |
415 | ||
416 | rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom); | |
417 | if (rval) { | |
418 | dev_err(&nvmem->dev, | |
419 | "Failed to create eeprom binary file %d\n", rval); | |
420 | return rval; | |
421 | } | |
422 | ||
423 | nvmem->flags |= FLAG_COMPAT; | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
eace75cf SK |
428 | /** |
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 | |
431 | * | |
432 | * @config: nvmem device configuration with which nvmem device is created. | |
433 | * | |
434 | * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device | |
435 | * on success. | |
436 | */ | |
437 | ||
438 | struct nvmem_device *nvmem_register(const struct nvmem_config *config) | |
439 | { | |
440 | struct nvmem_device *nvmem; | |
441 | struct device_node *np; | |
eace75cf SK |
442 | int rval; |
443 | ||
444 | if (!config->dev) | |
445 | return ERR_PTR(-EINVAL); | |
446 | ||
eace75cf SK |
447 | nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL); |
448 | if (!nvmem) | |
449 | return ERR_PTR(-ENOMEM); | |
450 | ||
451 | rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL); | |
452 | if (rval < 0) { | |
453 | kfree(nvmem); | |
454 | return ERR_PTR(rval); | |
455 | } | |
456 | ||
457 | nvmem->id = rval; | |
eace75cf | 458 | nvmem->owner = config->owner; |
795ddd18 SK |
459 | nvmem->stride = config->stride; |
460 | nvmem->word_size = config->word_size; | |
461 | nvmem->size = config->size; | |
eace75cf SK |
462 | nvmem->dev.type = &nvmem_provider_type; |
463 | nvmem->dev.bus = &nvmem_bus_type; | |
464 | nvmem->dev.parent = config->dev; | |
795ddd18 SK |
465 | nvmem->priv = config->priv; |
466 | nvmem->reg_read = config->reg_read; | |
467 | nvmem->reg_write = config->reg_write; | |
eace75cf SK |
468 | np = config->dev->of_node; |
469 | nvmem->dev.of_node = np; | |
470 | dev_set_name(&nvmem->dev, "%s%d", | |
471 | config->name ? : "nvmem", config->id); | |
472 | ||
473 | nvmem->read_only = of_property_read_bool(np, "read-only") | | |
474 | config->read_only; | |
475 | ||
811b0d65 AL |
476 | if (config->root_only) |
477 | nvmem->dev.groups = nvmem->read_only ? | |
478 | nvmem_ro_root_dev_groups : | |
479 | nvmem_rw_root_dev_groups; | |
480 | else | |
481 | nvmem->dev.groups = nvmem->read_only ? | |
482 | nvmem_ro_dev_groups : | |
483 | nvmem_rw_dev_groups; | |
eace75cf SK |
484 | |
485 | device_initialize(&nvmem->dev); | |
486 | ||
487 | dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); | |
488 | ||
489 | rval = device_add(&nvmem->dev); | |
b6c217ab AL |
490 | if (rval) |
491 | goto out; | |
492 | ||
493 | if (config->compat) { | |
494 | rval = nvmem_setup_compat(nvmem, config); | |
495 | if (rval) | |
496 | goto out; | |
eace75cf SK |
497 | } |
498 | ||
499 | if (config->cells) | |
500 | nvmem_add_cells(nvmem, config); | |
501 | ||
502 | return nvmem; | |
b6c217ab AL |
503 | out: |
504 | ida_simple_remove(&nvmem_ida, nvmem->id); | |
505 | kfree(nvmem); | |
506 | return ERR_PTR(rval); | |
eace75cf SK |
507 | } |
508 | EXPORT_SYMBOL_GPL(nvmem_register); | |
509 | ||
510 | /** | |
511 | * nvmem_unregister() - Unregister previously registered nvmem device | |
512 | * | |
513 | * @nvmem: Pointer to previously registered nvmem device. | |
514 | * | |
515 | * Return: Will be an negative on error or a zero on success. | |
516 | */ | |
517 | int nvmem_unregister(struct nvmem_device *nvmem) | |
518 | { | |
69aba794 SK |
519 | mutex_lock(&nvmem_mutex); |
520 | if (nvmem->users) { | |
521 | mutex_unlock(&nvmem_mutex); | |
eace75cf | 522 | return -EBUSY; |
69aba794 SK |
523 | } |
524 | mutex_unlock(&nvmem_mutex); | |
eace75cf | 525 | |
b6c217ab AL |
526 | if (nvmem->flags & FLAG_COMPAT) |
527 | device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); | |
528 | ||
eace75cf SK |
529 | nvmem_device_remove_all_cells(nvmem); |
530 | device_del(&nvmem->dev); | |
531 | ||
532 | return 0; | |
533 | } | |
534 | EXPORT_SYMBOL_GPL(nvmem_unregister); | |
535 | ||
69aba794 SK |
536 | static struct nvmem_device *__nvmem_device_get(struct device_node *np, |
537 | struct nvmem_cell **cellp, | |
538 | const char *cell_id) | |
539 | { | |
540 | struct nvmem_device *nvmem = NULL; | |
541 | ||
542 | mutex_lock(&nvmem_mutex); | |
543 | ||
544 | if (np) { | |
545 | nvmem = of_nvmem_find(np); | |
546 | if (!nvmem) { | |
547 | mutex_unlock(&nvmem_mutex); | |
548 | return ERR_PTR(-EPROBE_DEFER); | |
549 | } | |
550 | } else { | |
551 | struct nvmem_cell *cell = nvmem_find_cell(cell_id); | |
552 | ||
553 | if (cell) { | |
554 | nvmem = cell->nvmem; | |
555 | *cellp = cell; | |
556 | } | |
557 | ||
558 | if (!nvmem) { | |
559 | mutex_unlock(&nvmem_mutex); | |
560 | return ERR_PTR(-ENOENT); | |
561 | } | |
562 | } | |
563 | ||
564 | nvmem->users++; | |
565 | mutex_unlock(&nvmem_mutex); | |
566 | ||
567 | if (!try_module_get(nvmem->owner)) { | |
568 | dev_err(&nvmem->dev, | |
569 | "could not increase module refcount for cell %s\n", | |
570 | nvmem->name); | |
571 | ||
572 | mutex_lock(&nvmem_mutex); | |
573 | nvmem->users--; | |
574 | mutex_unlock(&nvmem_mutex); | |
575 | ||
576 | return ERR_PTR(-EINVAL); | |
577 | } | |
578 | ||
579 | return nvmem; | |
580 | } | |
581 | ||
582 | static void __nvmem_device_put(struct nvmem_device *nvmem) | |
583 | { | |
584 | module_put(nvmem->owner); | |
585 | mutex_lock(&nvmem_mutex); | |
586 | nvmem->users--; | |
587 | mutex_unlock(&nvmem_mutex); | |
588 | } | |
589 | ||
e2a5402e SK |
590 | static int nvmem_match(struct device *dev, void *data) |
591 | { | |
592 | return !strcmp(dev_name(dev), data); | |
593 | } | |
594 | ||
595 | static struct nvmem_device *nvmem_find(const char *name) | |
596 | { | |
597 | struct device *d; | |
598 | ||
599 | d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match); | |
600 | ||
601 | if (!d) | |
602 | return NULL; | |
603 | ||
604 | return to_nvmem_device(d); | |
605 | } | |
606 | ||
607 | #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF) | |
608 | /** | |
609 | * of_nvmem_device_get() - Get nvmem device from a given id | |
610 | * | |
611 | * @dev node: Device tree node that uses the nvmem device | |
612 | * @id: nvmem name from nvmem-names property. | |
613 | * | |
614 | * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device | |
615 | * on success. | |
616 | */ | |
617 | struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id) | |
618 | { | |
619 | ||
620 | struct device_node *nvmem_np; | |
621 | int index; | |
622 | ||
623 | index = of_property_match_string(np, "nvmem-names", id); | |
624 | ||
625 | nvmem_np = of_parse_phandle(np, "nvmem", index); | |
626 | if (!nvmem_np) | |
627 | return ERR_PTR(-EINVAL); | |
628 | ||
629 | return __nvmem_device_get(nvmem_np, NULL, NULL); | |
630 | } | |
631 | EXPORT_SYMBOL_GPL(of_nvmem_device_get); | |
632 | #endif | |
633 | ||
634 | /** | |
635 | * nvmem_device_get() - Get nvmem device from a given id | |
636 | * | |
637 | * @dev : Device that uses the nvmem device | |
638 | * @id: nvmem name from nvmem-names property. | |
639 | * | |
640 | * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device | |
641 | * on success. | |
642 | */ | |
643 | struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name) | |
644 | { | |
645 | if (dev->of_node) { /* try dt first */ | |
646 | struct nvmem_device *nvmem; | |
647 | ||
648 | nvmem = of_nvmem_device_get(dev->of_node, dev_name); | |
649 | ||
650 | if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER) | |
651 | return nvmem; | |
652 | ||
653 | } | |
654 | ||
655 | return nvmem_find(dev_name); | |
656 | } | |
657 | EXPORT_SYMBOL_GPL(nvmem_device_get); | |
658 | ||
659 | static int devm_nvmem_device_match(struct device *dev, void *res, void *data) | |
660 | { | |
661 | struct nvmem_device **nvmem = res; | |
662 | ||
663 | if (WARN_ON(!nvmem || !*nvmem)) | |
664 | return 0; | |
665 | ||
666 | return *nvmem == data; | |
667 | } | |
668 | ||
669 | static void devm_nvmem_device_release(struct device *dev, void *res) | |
670 | { | |
671 | nvmem_device_put(*(struct nvmem_device **)res); | |
672 | } | |
673 | ||
674 | /** | |
675 | * devm_nvmem_device_put() - put alredy got nvmem device | |
676 | * | |
677 | * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(), | |
678 | * that needs to be released. | |
679 | */ | |
680 | void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem) | |
681 | { | |
682 | int ret; | |
683 | ||
684 | ret = devres_release(dev, devm_nvmem_device_release, | |
685 | devm_nvmem_device_match, nvmem); | |
686 | ||
687 | WARN_ON(ret); | |
688 | } | |
689 | EXPORT_SYMBOL_GPL(devm_nvmem_device_put); | |
690 | ||
691 | /** | |
692 | * nvmem_device_put() - put alredy got nvmem device | |
693 | * | |
694 | * @nvmem: pointer to nvmem device that needs to be released. | |
695 | */ | |
696 | void nvmem_device_put(struct nvmem_device *nvmem) | |
697 | { | |
698 | __nvmem_device_put(nvmem); | |
699 | } | |
700 | EXPORT_SYMBOL_GPL(nvmem_device_put); | |
701 | ||
702 | /** | |
703 | * devm_nvmem_device_get() - Get nvmem cell of device form a given id | |
704 | * | |
705 | * @dev node: Device tree node that uses the nvmem cell | |
706 | * @id: nvmem name in nvmems property. | |
707 | * | |
708 | * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell | |
709 | * on success. The nvmem_cell will be freed by the automatically once the | |
710 | * device is freed. | |
711 | */ | |
712 | struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id) | |
713 | { | |
714 | struct nvmem_device **ptr, *nvmem; | |
715 | ||
716 | ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL); | |
717 | if (!ptr) | |
718 | return ERR_PTR(-ENOMEM); | |
719 | ||
720 | nvmem = nvmem_device_get(dev, id); | |
721 | if (!IS_ERR(nvmem)) { | |
722 | *ptr = nvmem; | |
723 | devres_add(dev, ptr); | |
724 | } else { | |
725 | devres_free(ptr); | |
726 | } | |
727 | ||
728 | return nvmem; | |
729 | } | |
730 | EXPORT_SYMBOL_GPL(devm_nvmem_device_get); | |
731 | ||
69aba794 SK |
732 | static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id) |
733 | { | |
734 | struct nvmem_cell *cell = NULL; | |
735 | struct nvmem_device *nvmem; | |
736 | ||
737 | nvmem = __nvmem_device_get(NULL, &cell, cell_id); | |
738 | if (IS_ERR(nvmem)) | |
739 | return ERR_CAST(nvmem); | |
740 | ||
741 | return cell; | |
742 | } | |
743 | ||
744 | #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF) | |
745 | /** | |
746 | * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id | |
747 | * | |
748 | * @dev node: Device tree node that uses the nvmem cell | |
749 | * @id: nvmem cell name from nvmem-cell-names property. | |
750 | * | |
751 | * Return: Will be an ERR_PTR() on error or a valid pointer | |
752 | * to a struct nvmem_cell. The nvmem_cell will be freed by the | |
753 | * nvmem_cell_put(). | |
754 | */ | |
755 | struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, | |
756 | const char *name) | |
757 | { | |
758 | struct device_node *cell_np, *nvmem_np; | |
759 | struct nvmem_cell *cell; | |
760 | struct nvmem_device *nvmem; | |
761 | const __be32 *addr; | |
762 | int rval, len, index; | |
763 | ||
764 | index = of_property_match_string(np, "nvmem-cell-names", name); | |
765 | ||
766 | cell_np = of_parse_phandle(np, "nvmem-cells", index); | |
767 | if (!cell_np) | |
768 | return ERR_PTR(-EINVAL); | |
769 | ||
770 | nvmem_np = of_get_next_parent(cell_np); | |
771 | if (!nvmem_np) | |
772 | return ERR_PTR(-EINVAL); | |
773 | ||
774 | nvmem = __nvmem_device_get(nvmem_np, NULL, NULL); | |
775 | if (IS_ERR(nvmem)) | |
776 | return ERR_CAST(nvmem); | |
777 | ||
778 | addr = of_get_property(cell_np, "reg", &len); | |
779 | if (!addr || (len < 2 * sizeof(u32))) { | |
780 | dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n", | |
781 | cell_np->full_name); | |
782 | rval = -EINVAL; | |
783 | goto err_mem; | |
784 | } | |
785 | ||
786 | cell = kzalloc(sizeof(*cell), GFP_KERNEL); | |
787 | if (!cell) { | |
788 | rval = -ENOMEM; | |
789 | goto err_mem; | |
790 | } | |
791 | ||
792 | cell->nvmem = nvmem; | |
793 | cell->offset = be32_to_cpup(addr++); | |
794 | cell->bytes = be32_to_cpup(addr); | |
795 | cell->name = cell_np->name; | |
796 | ||
797 | addr = of_get_property(cell_np, "bits", &len); | |
798 | if (addr && len == (2 * sizeof(u32))) { | |
799 | cell->bit_offset = be32_to_cpup(addr++); | |
800 | cell->nbits = be32_to_cpup(addr); | |
801 | } | |
802 | ||
803 | if (cell->nbits) | |
804 | cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset, | |
805 | BITS_PER_BYTE); | |
806 | ||
807 | if (!IS_ALIGNED(cell->offset, nvmem->stride)) { | |
808 | dev_err(&nvmem->dev, | |
809 | "cell %s unaligned to nvmem stride %d\n", | |
810 | cell->name, nvmem->stride); | |
811 | rval = -EINVAL; | |
812 | goto err_sanity; | |
813 | } | |
814 | ||
815 | nvmem_cell_add(cell); | |
816 | ||
817 | return cell; | |
818 | ||
819 | err_sanity: | |
820 | kfree(cell); | |
821 | ||
822 | err_mem: | |
823 | __nvmem_device_put(nvmem); | |
824 | ||
825 | return ERR_PTR(rval); | |
826 | } | |
827 | EXPORT_SYMBOL_GPL(of_nvmem_cell_get); | |
828 | #endif | |
829 | ||
830 | /** | |
831 | * nvmem_cell_get() - Get nvmem cell of device form a given cell name | |
832 | * | |
833 | * @dev node: Device tree node that uses the nvmem cell | |
834 | * @id: nvmem cell name to get. | |
835 | * | |
836 | * Return: Will be an ERR_PTR() on error or a valid pointer | |
837 | * to a struct nvmem_cell. The nvmem_cell will be freed by the | |
838 | * nvmem_cell_put(). | |
839 | */ | |
840 | struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id) | |
841 | { | |
842 | struct nvmem_cell *cell; | |
843 | ||
844 | if (dev->of_node) { /* try dt first */ | |
845 | cell = of_nvmem_cell_get(dev->of_node, cell_id); | |
846 | if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER) | |
847 | return cell; | |
848 | } | |
849 | ||
850 | return nvmem_cell_get_from_list(cell_id); | |
851 | } | |
852 | EXPORT_SYMBOL_GPL(nvmem_cell_get); | |
853 | ||
854 | static void devm_nvmem_cell_release(struct device *dev, void *res) | |
855 | { | |
856 | nvmem_cell_put(*(struct nvmem_cell **)res); | |
857 | } | |
858 | ||
859 | /** | |
860 | * devm_nvmem_cell_get() - Get nvmem cell of device form a given id | |
861 | * | |
862 | * @dev node: Device tree node that uses the nvmem cell | |
863 | * @id: nvmem id in nvmem-names property. | |
864 | * | |
865 | * Return: Will be an ERR_PTR() on error or a valid pointer | |
866 | * to a struct nvmem_cell. The nvmem_cell will be freed by the | |
867 | * automatically once the device is freed. | |
868 | */ | |
869 | struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id) | |
870 | { | |
871 | struct nvmem_cell **ptr, *cell; | |
872 | ||
873 | ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL); | |
874 | if (!ptr) | |
875 | return ERR_PTR(-ENOMEM); | |
876 | ||
877 | cell = nvmem_cell_get(dev, id); | |
878 | if (!IS_ERR(cell)) { | |
879 | *ptr = cell; | |
880 | devres_add(dev, ptr); | |
881 | } else { | |
882 | devres_free(ptr); | |
883 | } | |
884 | ||
885 | return cell; | |
886 | } | |
887 | EXPORT_SYMBOL_GPL(devm_nvmem_cell_get); | |
888 | ||
889 | static int devm_nvmem_cell_match(struct device *dev, void *res, void *data) | |
890 | { | |
891 | struct nvmem_cell **c = res; | |
892 | ||
893 | if (WARN_ON(!c || !*c)) | |
894 | return 0; | |
895 | ||
896 | return *c == data; | |
897 | } | |
898 | ||
899 | /** | |
900 | * devm_nvmem_cell_put() - Release previously allocated nvmem cell | |
901 | * from devm_nvmem_cell_get. | |
902 | * | |
903 | * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get() | |
904 | */ | |
905 | void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell) | |
906 | { | |
907 | int ret; | |
908 | ||
909 | ret = devres_release(dev, devm_nvmem_cell_release, | |
910 | devm_nvmem_cell_match, cell); | |
911 | ||
912 | WARN_ON(ret); | |
913 | } | |
914 | EXPORT_SYMBOL(devm_nvmem_cell_put); | |
915 | ||
916 | /** | |
917 | * nvmem_cell_put() - Release previously allocated nvmem cell. | |
918 | * | |
919 | * @cell: Previously allocated nvmem cell by nvmem_cell_get() | |
920 | */ | |
921 | void nvmem_cell_put(struct nvmem_cell *cell) | |
922 | { | |
923 | struct nvmem_device *nvmem = cell->nvmem; | |
924 | ||
925 | __nvmem_device_put(nvmem); | |
926 | nvmem_cell_drop(cell); | |
927 | } | |
928 | EXPORT_SYMBOL_GPL(nvmem_cell_put); | |
929 | ||
930 | static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, | |
931 | void *buf) | |
932 | { | |
933 | u8 *p, *b; | |
934 | int i, bit_offset = cell->bit_offset; | |
935 | ||
936 | p = b = buf; | |
937 | if (bit_offset) { | |
938 | /* First shift */ | |
939 | *b++ >>= bit_offset; | |
940 | ||
941 | /* setup rest of the bytes if any */ | |
942 | for (i = 1; i < cell->bytes; i++) { | |
943 | /* Get bits from next byte and shift them towards msb */ | |
944 | *p |= *b << (BITS_PER_BYTE - bit_offset); | |
945 | ||
946 | p = b; | |
947 | *b++ >>= bit_offset; | |
948 | } | |
949 | ||
950 | /* result fits in less bytes */ | |
951 | if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE)) | |
952 | *p-- = 0; | |
953 | } | |
954 | /* clear msb bits if any leftover in the last byte */ | |
955 | *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0); | |
956 | } | |
957 | ||
958 | static int __nvmem_cell_read(struct nvmem_device *nvmem, | |
959 | struct nvmem_cell *cell, | |
960 | void *buf, size_t *len) | |
961 | { | |
962 | int rc; | |
963 | ||
795ddd18 | 964 | rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes); |
69aba794 | 965 | |
287980e4 | 966 | if (rc) |
69aba794 SK |
967 | return rc; |
968 | ||
969 | /* shift bits in-place */ | |
cbf854ab | 970 | if (cell->bit_offset || cell->nbits) |
69aba794 SK |
971 | nvmem_shift_read_buffer_in_place(cell, buf); |
972 | ||
973 | *len = cell->bytes; | |
974 | ||
975 | return 0; | |
976 | } | |
977 | ||
978 | /** | |
979 | * nvmem_cell_read() - Read a given nvmem cell | |
980 | * | |
981 | * @cell: nvmem cell to be read. | |
982 | * @len: pointer to length of cell which will be populated on successful read. | |
983 | * | |
984 | * Return: ERR_PTR() on error or a valid pointer to a char * buffer on success. | |
985 | * The buffer should be freed by the consumer with a kfree(). | |
986 | */ | |
987 | void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len) | |
988 | { | |
989 | struct nvmem_device *nvmem = cell->nvmem; | |
990 | u8 *buf; | |
991 | int rc; | |
992 | ||
795ddd18 | 993 | if (!nvmem) |
69aba794 SK |
994 | return ERR_PTR(-EINVAL); |
995 | ||
996 | buf = kzalloc(cell->bytes, GFP_KERNEL); | |
997 | if (!buf) | |
998 | return ERR_PTR(-ENOMEM); | |
999 | ||
1000 | rc = __nvmem_cell_read(nvmem, cell, buf, len); | |
287980e4 | 1001 | if (rc) { |
69aba794 SK |
1002 | kfree(buf); |
1003 | return ERR_PTR(rc); | |
1004 | } | |
1005 | ||
1006 | return buf; | |
1007 | } | |
1008 | EXPORT_SYMBOL_GPL(nvmem_cell_read); | |
1009 | ||
1010 | static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell, | |
1011 | u8 *_buf, int len) | |
1012 | { | |
1013 | struct nvmem_device *nvmem = cell->nvmem; | |
1014 | int i, rc, nbits, bit_offset = cell->bit_offset; | |
1015 | u8 v, *p, *buf, *b, pbyte, pbits; | |
1016 | ||
1017 | nbits = cell->nbits; | |
1018 | buf = kzalloc(cell->bytes, GFP_KERNEL); | |
1019 | if (!buf) | |
1020 | return ERR_PTR(-ENOMEM); | |
1021 | ||
1022 | memcpy(buf, _buf, len); | |
1023 | p = b = buf; | |
1024 | ||
1025 | if (bit_offset) { | |
1026 | pbyte = *b; | |
1027 | *b <<= bit_offset; | |
1028 | ||
1029 | /* setup the first byte with lsb bits from nvmem */ | |
795ddd18 | 1030 | rc = nvmem_reg_read(nvmem, cell->offset, &v, 1); |
69aba794 SK |
1031 | *b++ |= GENMASK(bit_offset - 1, 0) & v; |
1032 | ||
1033 | /* setup rest of the byte if any */ | |
1034 | for (i = 1; i < cell->bytes; i++) { | |
1035 | /* Get last byte bits and shift them towards lsb */ | |
1036 | pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset); | |
1037 | pbyte = *b; | |
1038 | p = b; | |
1039 | *b <<= bit_offset; | |
1040 | *b++ |= pbits; | |
1041 | } | |
1042 | } | |
1043 | ||
1044 | /* if it's not end on byte boundary */ | |
1045 | if ((nbits + bit_offset) % BITS_PER_BYTE) { | |
1046 | /* setup the last byte with msb bits from nvmem */ | |
795ddd18 | 1047 | rc = nvmem_reg_read(nvmem, |
69aba794 SK |
1048 | cell->offset + cell->bytes - 1, &v, 1); |
1049 | *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v; | |
1050 | ||
1051 | } | |
1052 | ||
1053 | return buf; | |
1054 | } | |
1055 | ||
1056 | /** | |
1057 | * nvmem_cell_write() - Write to a given nvmem cell | |
1058 | * | |
1059 | * @cell: nvmem cell to be written. | |
1060 | * @buf: Buffer to be written. | |
1061 | * @len: length of buffer to be written to nvmem cell. | |
1062 | * | |
1063 | * Return: length of bytes written or negative on failure. | |
1064 | */ | |
1065 | int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len) | |
1066 | { | |
1067 | struct nvmem_device *nvmem = cell->nvmem; | |
1068 | int rc; | |
1069 | ||
795ddd18 | 1070 | if (!nvmem || nvmem->read_only || |
69aba794 SK |
1071 | (cell->bit_offset == 0 && len != cell->bytes)) |
1072 | return -EINVAL; | |
1073 | ||
1074 | if (cell->bit_offset || cell->nbits) { | |
1075 | buf = nvmem_cell_prepare_write_buffer(cell, buf, len); | |
1076 | if (IS_ERR(buf)) | |
1077 | return PTR_ERR(buf); | |
1078 | } | |
1079 | ||
795ddd18 | 1080 | rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes); |
69aba794 SK |
1081 | |
1082 | /* free the tmp buffer */ | |
ace22170 | 1083 | if (cell->bit_offset || cell->nbits) |
69aba794 SK |
1084 | kfree(buf); |
1085 | ||
287980e4 | 1086 | if (rc) |
69aba794 SK |
1087 | return rc; |
1088 | ||
1089 | return len; | |
1090 | } | |
1091 | EXPORT_SYMBOL_GPL(nvmem_cell_write); | |
1092 | ||
e2a5402e SK |
1093 | /** |
1094 | * nvmem_device_cell_read() - Read a given nvmem device and cell | |
1095 | * | |
1096 | * @nvmem: nvmem device to read from. | |
1097 | * @info: nvmem cell info to be read. | |
1098 | * @buf: buffer pointer which will be populated on successful read. | |
1099 | * | |
1100 | * Return: length of successful bytes read on success and negative | |
1101 | * error code on error. | |
1102 | */ | |
1103 | ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem, | |
1104 | struct nvmem_cell_info *info, void *buf) | |
1105 | { | |
1106 | struct nvmem_cell cell; | |
1107 | int rc; | |
1108 | ssize_t len; | |
1109 | ||
795ddd18 | 1110 | if (!nvmem) |
e2a5402e SK |
1111 | return -EINVAL; |
1112 | ||
1113 | rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell); | |
287980e4 | 1114 | if (rc) |
e2a5402e SK |
1115 | return rc; |
1116 | ||
1117 | rc = __nvmem_cell_read(nvmem, &cell, buf, &len); | |
287980e4 | 1118 | if (rc) |
e2a5402e SK |
1119 | return rc; |
1120 | ||
1121 | return len; | |
1122 | } | |
1123 | EXPORT_SYMBOL_GPL(nvmem_device_cell_read); | |
1124 | ||
1125 | /** | |
1126 | * nvmem_device_cell_write() - Write cell to a given nvmem device | |
1127 | * | |
1128 | * @nvmem: nvmem device to be written to. | |
1129 | * @info: nvmem cell info to be written | |
1130 | * @buf: buffer to be written to cell. | |
1131 | * | |
1132 | * Return: length of bytes written or negative error code on failure. | |
1133 | * */ | |
1134 | int nvmem_device_cell_write(struct nvmem_device *nvmem, | |
1135 | struct nvmem_cell_info *info, void *buf) | |
1136 | { | |
1137 | struct nvmem_cell cell; | |
1138 | int rc; | |
1139 | ||
795ddd18 | 1140 | if (!nvmem) |
e2a5402e SK |
1141 | return -EINVAL; |
1142 | ||
1143 | rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell); | |
287980e4 | 1144 | if (rc) |
e2a5402e SK |
1145 | return rc; |
1146 | ||
1147 | return nvmem_cell_write(&cell, buf, cell.bytes); | |
1148 | } | |
1149 | EXPORT_SYMBOL_GPL(nvmem_device_cell_write); | |
1150 | ||
1151 | /** | |
1152 | * nvmem_device_read() - Read from a given nvmem device | |
1153 | * | |
1154 | * @nvmem: nvmem device to read from. | |
1155 | * @offset: offset in nvmem device. | |
1156 | * @bytes: number of bytes to read. | |
1157 | * @buf: buffer pointer which will be populated on successful read. | |
1158 | * | |
1159 | * Return: length of successful bytes read on success and negative | |
1160 | * error code on error. | |
1161 | */ | |
1162 | int nvmem_device_read(struct nvmem_device *nvmem, | |
1163 | unsigned int offset, | |
1164 | size_t bytes, void *buf) | |
1165 | { | |
1166 | int rc; | |
1167 | ||
795ddd18 | 1168 | if (!nvmem) |
e2a5402e SK |
1169 | return -EINVAL; |
1170 | ||
795ddd18 | 1171 | rc = nvmem_reg_read(nvmem, offset, buf, bytes); |
e2a5402e | 1172 | |
287980e4 | 1173 | if (rc) |
e2a5402e SK |
1174 | return rc; |
1175 | ||
1176 | return bytes; | |
1177 | } | |
1178 | EXPORT_SYMBOL_GPL(nvmem_device_read); | |
1179 | ||
1180 | /** | |
1181 | * nvmem_device_write() - Write cell to a given nvmem device | |
1182 | * | |
1183 | * @nvmem: nvmem device to be written to. | |
1184 | * @offset: offset in nvmem device. | |
1185 | * @bytes: number of bytes to write. | |
1186 | * @buf: buffer to be written. | |
1187 | * | |
1188 | * Return: length of bytes written or negative error code on failure. | |
1189 | * */ | |
1190 | int nvmem_device_write(struct nvmem_device *nvmem, | |
1191 | unsigned int offset, | |
1192 | size_t bytes, void *buf) | |
1193 | { | |
1194 | int rc; | |
1195 | ||
795ddd18 | 1196 | if (!nvmem) |
e2a5402e SK |
1197 | return -EINVAL; |
1198 | ||
795ddd18 | 1199 | rc = nvmem_reg_write(nvmem, offset, buf, bytes); |
e2a5402e | 1200 | |
287980e4 | 1201 | if (rc) |
e2a5402e SK |
1202 | return rc; |
1203 | ||
1204 | ||
1205 | return bytes; | |
1206 | } | |
1207 | EXPORT_SYMBOL_GPL(nvmem_device_write); | |
1208 | ||
eace75cf SK |
1209 | static int __init nvmem_init(void) |
1210 | { | |
1211 | return bus_register(&nvmem_bus_type); | |
1212 | } | |
1213 | ||
1214 | static void __exit nvmem_exit(void) | |
1215 | { | |
1216 | bus_unregister(&nvmem_bus_type); | |
1217 | } | |
1218 | ||
1219 | subsys_initcall(nvmem_init); | |
1220 | module_exit(nvmem_exit); | |
1221 | ||
1222 | MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org"); | |
1223 | MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); | |
1224 | MODULE_DESCRIPTION("nvmem Driver Core"); | |
1225 | MODULE_LICENSE("GPL v2"); |