Loading...
Note: File does not exist in v3.1.
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Reset Controller framework
4 *
5 * Copyright 2013 Philipp Zabel, Pengutronix
6 */
7#include <linux/atomic.h>
8#include <linux/device.h>
9#include <linux/err.h>
10#include <linux/export.h>
11#include <linux/kernel.h>
12#include <linux/kref.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/reset.h>
16#include <linux/reset-controller.h>
17#include <linux/slab.h>
18
19static DEFINE_MUTEX(reset_list_mutex);
20static LIST_HEAD(reset_controller_list);
21
22static DEFINE_MUTEX(reset_lookup_mutex);
23static LIST_HEAD(reset_lookup_list);
24
25/**
26 * struct reset_control - a reset control
27 * @rcdev: a pointer to the reset controller device
28 * this reset control belongs to
29 * @list: list entry for the rcdev's reset controller list
30 * @id: ID of the reset controller in the reset
31 * controller device
32 * @refcnt: Number of gets of this reset_control
33 * @acquired: Only one reset_control may be acquired for a given rcdev and id.
34 * @shared: Is this a shared (1), or an exclusive (0) reset_control?
35 * @deassert_cnt: Number of times this reset line has been deasserted
36 * @triggered_count: Number of times this reset line has been reset. Currently
37 * only used for shared resets, which means that the value
38 * will be either 0 or 1.
39 */
40struct reset_control {
41 struct reset_controller_dev *rcdev;
42 struct list_head list;
43 unsigned int id;
44 struct kref refcnt;
45 bool acquired;
46 bool shared;
47 bool array;
48 atomic_t deassert_count;
49 atomic_t triggered_count;
50};
51
52/**
53 * struct reset_control_array - an array of reset controls
54 * @base: reset control for compatibility with reset control API functions
55 * @num_rstcs: number of reset controls
56 * @rstc: array of reset controls
57 */
58struct reset_control_array {
59 struct reset_control base;
60 unsigned int num_rstcs;
61 struct reset_control *rstc[];
62};
63
64static const char *rcdev_name(struct reset_controller_dev *rcdev)
65{
66 if (rcdev->dev)
67 return dev_name(rcdev->dev);
68
69 if (rcdev->of_node)
70 return rcdev->of_node->full_name;
71
72 return NULL;
73}
74
75/**
76 * of_reset_simple_xlate - translate reset_spec to the reset line number
77 * @rcdev: a pointer to the reset controller device
78 * @reset_spec: reset line specifier as found in the device tree
79 *
80 * This simple translation function should be used for reset controllers
81 * with 1:1 mapping, where reset lines can be indexed by number without gaps.
82 */
83static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
84 const struct of_phandle_args *reset_spec)
85{
86 if (reset_spec->args[0] >= rcdev->nr_resets)
87 return -EINVAL;
88
89 return reset_spec->args[0];
90}
91
92/**
93 * reset_controller_register - register a reset controller device
94 * @rcdev: a pointer to the initialized reset controller device
95 */
96int reset_controller_register(struct reset_controller_dev *rcdev)
97{
98 if (!rcdev->of_xlate) {
99 rcdev->of_reset_n_cells = 1;
100 rcdev->of_xlate = of_reset_simple_xlate;
101 }
102
103 INIT_LIST_HEAD(&rcdev->reset_control_head);
104
105 mutex_lock(&reset_list_mutex);
106 list_add(&rcdev->list, &reset_controller_list);
107 mutex_unlock(&reset_list_mutex);
108
109 return 0;
110}
111EXPORT_SYMBOL_GPL(reset_controller_register);
112
113/**
114 * reset_controller_unregister - unregister a reset controller device
115 * @rcdev: a pointer to the reset controller device
116 */
117void reset_controller_unregister(struct reset_controller_dev *rcdev)
118{
119 mutex_lock(&reset_list_mutex);
120 list_del(&rcdev->list);
121 mutex_unlock(&reset_list_mutex);
122}
123EXPORT_SYMBOL_GPL(reset_controller_unregister);
124
125static void devm_reset_controller_release(struct device *dev, void *res)
126{
127 reset_controller_unregister(*(struct reset_controller_dev **)res);
128}
129
130/**
131 * devm_reset_controller_register - resource managed reset_controller_register()
132 * @dev: device that is registering this reset controller
133 * @rcdev: a pointer to the initialized reset controller device
134 *
135 * Managed reset_controller_register(). For reset controllers registered by
136 * this function, reset_controller_unregister() is automatically called on
137 * driver detach. See reset_controller_register() for more information.
138 */
139int devm_reset_controller_register(struct device *dev,
140 struct reset_controller_dev *rcdev)
141{
142 struct reset_controller_dev **rcdevp;
143 int ret;
144
145 rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
146 GFP_KERNEL);
147 if (!rcdevp)
148 return -ENOMEM;
149
150 ret = reset_controller_register(rcdev);
151 if (!ret) {
152 *rcdevp = rcdev;
153 devres_add(dev, rcdevp);
154 } else {
155 devres_free(rcdevp);
156 }
157
158 return ret;
159}
160EXPORT_SYMBOL_GPL(devm_reset_controller_register);
161
162/**
163 * reset_controller_add_lookup - register a set of lookup entries
164 * @lookup: array of reset lookup entries
165 * @num_entries: number of entries in the lookup array
166 */
167void reset_controller_add_lookup(struct reset_control_lookup *lookup,
168 unsigned int num_entries)
169{
170 struct reset_control_lookup *entry;
171 unsigned int i;
172
173 mutex_lock(&reset_lookup_mutex);
174 for (i = 0; i < num_entries; i++) {
175 entry = &lookup[i];
176
177 if (!entry->dev_id || !entry->provider) {
178 pr_warn("%s(): reset lookup entry badly specified, skipping\n",
179 __func__);
180 continue;
181 }
182
183 list_add_tail(&entry->list, &reset_lookup_list);
184 }
185 mutex_unlock(&reset_lookup_mutex);
186}
187EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
188
189static inline struct reset_control_array *
190rstc_to_array(struct reset_control *rstc) {
191 return container_of(rstc, struct reset_control_array, base);
192}
193
194static int reset_control_array_reset(struct reset_control_array *resets)
195{
196 int ret, i;
197
198 for (i = 0; i < resets->num_rstcs; i++) {
199 ret = reset_control_reset(resets->rstc[i]);
200 if (ret)
201 return ret;
202 }
203
204 return 0;
205}
206
207static int reset_control_array_assert(struct reset_control_array *resets)
208{
209 int ret, i;
210
211 for (i = 0; i < resets->num_rstcs; i++) {
212 ret = reset_control_assert(resets->rstc[i]);
213 if (ret)
214 goto err;
215 }
216
217 return 0;
218
219err:
220 while (i--)
221 reset_control_deassert(resets->rstc[i]);
222 return ret;
223}
224
225static int reset_control_array_deassert(struct reset_control_array *resets)
226{
227 int ret, i;
228
229 for (i = 0; i < resets->num_rstcs; i++) {
230 ret = reset_control_deassert(resets->rstc[i]);
231 if (ret)
232 goto err;
233 }
234
235 return 0;
236
237err:
238 while (i--)
239 reset_control_assert(resets->rstc[i]);
240 return ret;
241}
242
243static int reset_control_array_acquire(struct reset_control_array *resets)
244{
245 unsigned int i;
246 int err;
247
248 for (i = 0; i < resets->num_rstcs; i++) {
249 err = reset_control_acquire(resets->rstc[i]);
250 if (err < 0)
251 goto release;
252 }
253
254 return 0;
255
256release:
257 while (i--)
258 reset_control_release(resets->rstc[i]);
259
260 return err;
261}
262
263static void reset_control_array_release(struct reset_control_array *resets)
264{
265 unsigned int i;
266
267 for (i = 0; i < resets->num_rstcs; i++)
268 reset_control_release(resets->rstc[i]);
269}
270
271static inline bool reset_control_is_array(struct reset_control *rstc)
272{
273 return rstc->array;
274}
275
276/**
277 * reset_control_reset - reset the controlled device
278 * @rstc: reset controller
279 *
280 * On a shared reset line the actual reset pulse is only triggered once for the
281 * lifetime of the reset_control instance: for all but the first caller this is
282 * a no-op.
283 * Consumers must not use reset_control_(de)assert on shared reset lines when
284 * reset_control_reset has been used.
285 *
286 * If rstc is NULL it is an optional reset and the function will just
287 * return 0.
288 */
289int reset_control_reset(struct reset_control *rstc)
290{
291 int ret;
292
293 if (!rstc)
294 return 0;
295
296 if (WARN_ON(IS_ERR(rstc)))
297 return -EINVAL;
298
299 if (reset_control_is_array(rstc))
300 return reset_control_array_reset(rstc_to_array(rstc));
301
302 if (!rstc->rcdev->ops->reset)
303 return -ENOTSUPP;
304
305 if (rstc->shared) {
306 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
307 return -EINVAL;
308
309 if (atomic_inc_return(&rstc->triggered_count) != 1)
310 return 0;
311 } else {
312 if (!rstc->acquired)
313 return -EPERM;
314 }
315
316 ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
317 if (rstc->shared && ret)
318 atomic_dec(&rstc->triggered_count);
319
320 return ret;
321}
322EXPORT_SYMBOL_GPL(reset_control_reset);
323
324/**
325 * reset_control_assert - asserts the reset line
326 * @rstc: reset controller
327 *
328 * Calling this on an exclusive reset controller guarantees that the reset
329 * will be asserted. When called on a shared reset controller the line may
330 * still be deasserted, as long as other users keep it so.
331 *
332 * For shared reset controls a driver cannot expect the hw's registers and
333 * internal state to be reset, but must be prepared for this to happen.
334 * Consumers must not use reset_control_reset on shared reset lines when
335 * reset_control_(de)assert has been used.
336 * return 0.
337 *
338 * If rstc is NULL it is an optional reset and the function will just
339 * return 0.
340 */
341int reset_control_assert(struct reset_control *rstc)
342{
343 if (!rstc)
344 return 0;
345
346 if (WARN_ON(IS_ERR(rstc)))
347 return -EINVAL;
348
349 if (reset_control_is_array(rstc))
350 return reset_control_array_assert(rstc_to_array(rstc));
351
352 if (rstc->shared) {
353 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
354 return -EINVAL;
355
356 if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
357 return -EINVAL;
358
359 if (atomic_dec_return(&rstc->deassert_count) != 0)
360 return 0;
361
362 /*
363 * Shared reset controls allow the reset line to be in any state
364 * after this call, so doing nothing is a valid option.
365 */
366 if (!rstc->rcdev->ops->assert)
367 return 0;
368 } else {
369 /*
370 * If the reset controller does not implement .assert(), there
371 * is no way to guarantee that the reset line is asserted after
372 * this call.
373 */
374 if (!rstc->rcdev->ops->assert)
375 return -ENOTSUPP;
376
377 if (!rstc->acquired) {
378 WARN(1, "reset %s (ID: %u) is not acquired\n",
379 rcdev_name(rstc->rcdev), rstc->id);
380 return -EPERM;
381 }
382 }
383
384 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
385}
386EXPORT_SYMBOL_GPL(reset_control_assert);
387
388/**
389 * reset_control_deassert - deasserts the reset line
390 * @rstc: reset controller
391 *
392 * After calling this function, the reset is guaranteed to be deasserted.
393 * Consumers must not use reset_control_reset on shared reset lines when
394 * reset_control_(de)assert has been used.
395 * return 0.
396 *
397 * If rstc is NULL it is an optional reset and the function will just
398 * return 0.
399 */
400int reset_control_deassert(struct reset_control *rstc)
401{
402 if (!rstc)
403 return 0;
404
405 if (WARN_ON(IS_ERR(rstc)))
406 return -EINVAL;
407
408 if (reset_control_is_array(rstc))
409 return reset_control_array_deassert(rstc_to_array(rstc));
410
411 if (rstc->shared) {
412 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
413 return -EINVAL;
414
415 if (atomic_inc_return(&rstc->deassert_count) != 1)
416 return 0;
417 } else {
418 if (!rstc->acquired) {
419 WARN(1, "reset %s (ID: %u) is not acquired\n",
420 rcdev_name(rstc->rcdev), rstc->id);
421 return -EPERM;
422 }
423 }
424
425 /*
426 * If the reset controller does not implement .deassert(), we assume
427 * that it handles self-deasserting reset lines via .reset(). In that
428 * case, the reset lines are deasserted by default. If that is not the
429 * case, the reset controller driver should implement .deassert() and
430 * return -ENOTSUPP.
431 */
432 if (!rstc->rcdev->ops->deassert)
433 return 0;
434
435 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
436}
437EXPORT_SYMBOL_GPL(reset_control_deassert);
438
439/**
440 * reset_control_status - returns a negative errno if not supported, a
441 * positive value if the reset line is asserted, or zero if the reset
442 * line is not asserted or if the desc is NULL (optional reset).
443 * @rstc: reset controller
444 */
445int reset_control_status(struct reset_control *rstc)
446{
447 if (!rstc)
448 return 0;
449
450 if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
451 return -EINVAL;
452
453 if (rstc->rcdev->ops->status)
454 return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
455
456 return -ENOTSUPP;
457}
458EXPORT_SYMBOL_GPL(reset_control_status);
459
460/**
461 * reset_control_acquire() - acquires a reset control for exclusive use
462 * @rstc: reset control
463 *
464 * This is used to explicitly acquire a reset control for exclusive use. Note
465 * that exclusive resets are requested as acquired by default. In order for a
466 * second consumer to be able to control the reset, the first consumer has to
467 * release it first. Typically the easiest way to achieve this is to call the
468 * reset_control_get_exclusive_released() to obtain an instance of the reset
469 * control. Such reset controls are not acquired by default.
470 *
471 * Consumers implementing shared access to an exclusive reset need to follow
472 * a specific protocol in order to work together. Before consumers can change
473 * a reset they must acquire exclusive access using reset_control_acquire().
474 * After they are done operating the reset, they must release exclusive access
475 * with a call to reset_control_release(). Consumers are not granted exclusive
476 * access to the reset as long as another consumer hasn't released a reset.
477 *
478 * See also: reset_control_release()
479 */
480int reset_control_acquire(struct reset_control *rstc)
481{
482 struct reset_control *rc;
483
484 if (!rstc)
485 return 0;
486
487 if (WARN_ON(IS_ERR(rstc)))
488 return -EINVAL;
489
490 if (reset_control_is_array(rstc))
491 return reset_control_array_acquire(rstc_to_array(rstc));
492
493 mutex_lock(&reset_list_mutex);
494
495 if (rstc->acquired) {
496 mutex_unlock(&reset_list_mutex);
497 return 0;
498 }
499
500 list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
501 if (rstc != rc && rstc->id == rc->id) {
502 if (rc->acquired) {
503 mutex_unlock(&reset_list_mutex);
504 return -EBUSY;
505 }
506 }
507 }
508
509 rstc->acquired = true;
510
511 mutex_unlock(&reset_list_mutex);
512 return 0;
513}
514EXPORT_SYMBOL_GPL(reset_control_acquire);
515
516/**
517 * reset_control_release() - releases exclusive access to a reset control
518 * @rstc: reset control
519 *
520 * Releases exclusive access right to a reset control previously obtained by a
521 * call to reset_control_acquire(). Until a consumer calls this function, no
522 * other consumers will be granted exclusive access.
523 *
524 * See also: reset_control_acquire()
525 */
526void reset_control_release(struct reset_control *rstc)
527{
528 if (!rstc || WARN_ON(IS_ERR(rstc)))
529 return;
530
531 if (reset_control_is_array(rstc))
532 reset_control_array_release(rstc_to_array(rstc));
533 else
534 rstc->acquired = false;
535}
536EXPORT_SYMBOL_GPL(reset_control_release);
537
538static struct reset_control *__reset_control_get_internal(
539 struct reset_controller_dev *rcdev,
540 unsigned int index, bool shared, bool acquired)
541{
542 struct reset_control *rstc;
543
544 lockdep_assert_held(&reset_list_mutex);
545
546 list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
547 if (rstc->id == index) {
548 /*
549 * Allow creating a secondary exclusive reset_control
550 * that is initially not acquired for an already
551 * controlled reset line.
552 */
553 if (!rstc->shared && !shared && !acquired)
554 break;
555
556 if (WARN_ON(!rstc->shared || !shared))
557 return ERR_PTR(-EBUSY);
558
559 kref_get(&rstc->refcnt);
560 return rstc;
561 }
562 }
563
564 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
565 if (!rstc)
566 return ERR_PTR(-ENOMEM);
567
568 try_module_get(rcdev->owner);
569
570 rstc->rcdev = rcdev;
571 list_add(&rstc->list, &rcdev->reset_control_head);
572 rstc->id = index;
573 kref_init(&rstc->refcnt);
574 rstc->acquired = acquired;
575 rstc->shared = shared;
576
577 return rstc;
578}
579
580static void __reset_control_release(struct kref *kref)
581{
582 struct reset_control *rstc = container_of(kref, struct reset_control,
583 refcnt);
584
585 lockdep_assert_held(&reset_list_mutex);
586
587 module_put(rstc->rcdev->owner);
588
589 list_del(&rstc->list);
590 kfree(rstc);
591}
592
593static void __reset_control_put_internal(struct reset_control *rstc)
594{
595 lockdep_assert_held(&reset_list_mutex);
596
597 kref_put(&rstc->refcnt, __reset_control_release);
598}
599
600struct reset_control *__of_reset_control_get(struct device_node *node,
601 const char *id, int index, bool shared,
602 bool optional, bool acquired)
603{
604 struct reset_control *rstc;
605 struct reset_controller_dev *r, *rcdev;
606 struct of_phandle_args args;
607 int rstc_id;
608 int ret;
609
610 if (!node)
611 return ERR_PTR(-EINVAL);
612
613 if (id) {
614 index = of_property_match_string(node,
615 "reset-names", id);
616 if (index == -EILSEQ)
617 return ERR_PTR(index);
618 if (index < 0)
619 return optional ? NULL : ERR_PTR(-ENOENT);
620 }
621
622 ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
623 index, &args);
624 if (ret == -EINVAL)
625 return ERR_PTR(ret);
626 if (ret)
627 return optional ? NULL : ERR_PTR(ret);
628
629 mutex_lock(&reset_list_mutex);
630 rcdev = NULL;
631 list_for_each_entry(r, &reset_controller_list, list) {
632 if (args.np == r->of_node) {
633 rcdev = r;
634 break;
635 }
636 }
637
638 if (!rcdev) {
639 rstc = ERR_PTR(-EPROBE_DEFER);
640 goto out;
641 }
642
643 if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
644 rstc = ERR_PTR(-EINVAL);
645 goto out;
646 }
647
648 rstc_id = rcdev->of_xlate(rcdev, &args);
649 if (rstc_id < 0) {
650 rstc = ERR_PTR(rstc_id);
651 goto out;
652 }
653
654 /* reset_list_mutex also protects the rcdev's reset_control list */
655 rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
656
657out:
658 mutex_unlock(&reset_list_mutex);
659 of_node_put(args.np);
660
661 return rstc;
662}
663EXPORT_SYMBOL_GPL(__of_reset_control_get);
664
665static struct reset_controller_dev *
666__reset_controller_by_name(const char *name)
667{
668 struct reset_controller_dev *rcdev;
669
670 lockdep_assert_held(&reset_list_mutex);
671
672 list_for_each_entry(rcdev, &reset_controller_list, list) {
673 if (!rcdev->dev)
674 continue;
675
676 if (!strcmp(name, dev_name(rcdev->dev)))
677 return rcdev;
678 }
679
680 return NULL;
681}
682
683static struct reset_control *
684__reset_control_get_from_lookup(struct device *dev, const char *con_id,
685 bool shared, bool optional, bool acquired)
686{
687 const struct reset_control_lookup *lookup;
688 struct reset_controller_dev *rcdev;
689 const char *dev_id = dev_name(dev);
690 struct reset_control *rstc = NULL;
691
692 mutex_lock(&reset_lookup_mutex);
693
694 list_for_each_entry(lookup, &reset_lookup_list, list) {
695 if (strcmp(lookup->dev_id, dev_id))
696 continue;
697
698 if ((!con_id && !lookup->con_id) ||
699 ((con_id && lookup->con_id) &&
700 !strcmp(con_id, lookup->con_id))) {
701 mutex_lock(&reset_list_mutex);
702 rcdev = __reset_controller_by_name(lookup->provider);
703 if (!rcdev) {
704 mutex_unlock(&reset_list_mutex);
705 mutex_unlock(&reset_lookup_mutex);
706 /* Reset provider may not be ready yet. */
707 return ERR_PTR(-EPROBE_DEFER);
708 }
709
710 rstc = __reset_control_get_internal(rcdev,
711 lookup->index,
712 shared, acquired);
713 mutex_unlock(&reset_list_mutex);
714 break;
715 }
716 }
717
718 mutex_unlock(&reset_lookup_mutex);
719
720 if (!rstc)
721 return optional ? NULL : ERR_PTR(-ENOENT);
722
723 return rstc;
724}
725
726struct reset_control *__reset_control_get(struct device *dev, const char *id,
727 int index, bool shared, bool optional,
728 bool acquired)
729{
730 if (WARN_ON(shared && acquired))
731 return ERR_PTR(-EINVAL);
732
733 if (dev->of_node)
734 return __of_reset_control_get(dev->of_node, id, index, shared,
735 optional, acquired);
736
737 return __reset_control_get_from_lookup(dev, id, shared, optional,
738 acquired);
739}
740EXPORT_SYMBOL_GPL(__reset_control_get);
741
742static void reset_control_array_put(struct reset_control_array *resets)
743{
744 int i;
745
746 mutex_lock(&reset_list_mutex);
747 for (i = 0; i < resets->num_rstcs; i++)
748 __reset_control_put_internal(resets->rstc[i]);
749 mutex_unlock(&reset_list_mutex);
750 kfree(resets);
751}
752
753/**
754 * reset_control_put - free the reset controller
755 * @rstc: reset controller
756 */
757void reset_control_put(struct reset_control *rstc)
758{
759 if (IS_ERR_OR_NULL(rstc))
760 return;
761
762 if (reset_control_is_array(rstc)) {
763 reset_control_array_put(rstc_to_array(rstc));
764 return;
765 }
766
767 mutex_lock(&reset_list_mutex);
768 __reset_control_put_internal(rstc);
769 mutex_unlock(&reset_list_mutex);
770}
771EXPORT_SYMBOL_GPL(reset_control_put);
772
773static void devm_reset_control_release(struct device *dev, void *res)
774{
775 reset_control_put(*(struct reset_control **)res);
776}
777
778struct reset_control *__devm_reset_control_get(struct device *dev,
779 const char *id, int index, bool shared,
780 bool optional, bool acquired)
781{
782 struct reset_control **ptr, *rstc;
783
784 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
785 GFP_KERNEL);
786 if (!ptr)
787 return ERR_PTR(-ENOMEM);
788
789 rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
790 if (!IS_ERR(rstc)) {
791 *ptr = rstc;
792 devres_add(dev, ptr);
793 } else {
794 devres_free(ptr);
795 }
796
797 return rstc;
798}
799EXPORT_SYMBOL_GPL(__devm_reset_control_get);
800
801/**
802 * device_reset - find reset controller associated with the device
803 * and perform reset
804 * @dev: device to be reset by the controller
805 * @optional: whether it is optional to reset the device
806 *
807 * Convenience wrapper for __reset_control_get() and reset_control_reset().
808 * This is useful for the common case of devices with single, dedicated reset
809 * lines.
810 */
811int __device_reset(struct device *dev, bool optional)
812{
813 struct reset_control *rstc;
814 int ret;
815
816 rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
817 if (IS_ERR(rstc))
818 return PTR_ERR(rstc);
819
820 ret = reset_control_reset(rstc);
821
822 reset_control_put(rstc);
823
824 return ret;
825}
826EXPORT_SYMBOL_GPL(__device_reset);
827
828/*
829 * APIs to manage an array of reset controls.
830 */
831
832/**
833 * of_reset_control_get_count - Count number of resets available with a device
834 *
835 * @node: device node that contains 'resets'.
836 *
837 * Returns positive reset count on success, or error number on failure and
838 * on count being zero.
839 */
840static int of_reset_control_get_count(struct device_node *node)
841{
842 int count;
843
844 if (!node)
845 return -EINVAL;
846
847 count = of_count_phandle_with_args(node, "resets", "#reset-cells");
848 if (count == 0)
849 count = -ENOENT;
850
851 return count;
852}
853
854/**
855 * of_reset_control_array_get - Get a list of reset controls using
856 * device node.
857 *
858 * @np: device node for the device that requests the reset controls array
859 * @shared: whether reset controls are shared or not
860 * @optional: whether it is optional to get the reset controls
861 * @acquired: only one reset control may be acquired for a given controller
862 * and ID
863 *
864 * Returns pointer to allocated reset_control_array on success or
865 * error on failure
866 */
867struct reset_control *
868of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
869 bool acquired)
870{
871 struct reset_control_array *resets;
872 struct reset_control *rstc;
873 int num, i;
874
875 num = of_reset_control_get_count(np);
876 if (num < 0)
877 return optional ? NULL : ERR_PTR(num);
878
879 resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
880 if (!resets)
881 return ERR_PTR(-ENOMEM);
882
883 for (i = 0; i < num; i++) {
884 rstc = __of_reset_control_get(np, NULL, i, shared, optional,
885 acquired);
886 if (IS_ERR(rstc))
887 goto err_rst;
888 resets->rstc[i] = rstc;
889 }
890 resets->num_rstcs = num;
891 resets->base.array = true;
892
893 return &resets->base;
894
895err_rst:
896 mutex_lock(&reset_list_mutex);
897 while (--i >= 0)
898 __reset_control_put_internal(resets->rstc[i]);
899 mutex_unlock(&reset_list_mutex);
900
901 kfree(resets);
902
903 return rstc;
904}
905EXPORT_SYMBOL_GPL(of_reset_control_array_get);
906
907/**
908 * devm_reset_control_array_get - Resource managed reset control array get
909 *
910 * @dev: device that requests the list of reset controls
911 * @shared: whether reset controls are shared or not
912 * @optional: whether it is optional to get the reset controls
913 *
914 * The reset control array APIs are intended for a list of resets
915 * that just have to be asserted or deasserted, without any
916 * requirements on the order.
917 *
918 * Returns pointer to allocated reset_control_array on success or
919 * error on failure
920 */
921struct reset_control *
922devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
923{
924 struct reset_control **devres;
925 struct reset_control *rstc;
926
927 devres = devres_alloc(devm_reset_control_release, sizeof(*devres),
928 GFP_KERNEL);
929 if (!devres)
930 return ERR_PTR(-ENOMEM);
931
932 rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
933 if (IS_ERR(rstc)) {
934 devres_free(devres);
935 return rstc;
936 }
937
938 *devres = rstc;
939 devres_add(dev, devres);
940
941 return rstc;
942}
943EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
944
945static int reset_control_get_count_from_lookup(struct device *dev)
946{
947 const struct reset_control_lookup *lookup;
948 const char *dev_id;
949 int count = 0;
950
951 if (!dev)
952 return -EINVAL;
953
954 dev_id = dev_name(dev);
955 mutex_lock(&reset_lookup_mutex);
956
957 list_for_each_entry(lookup, &reset_lookup_list, list) {
958 if (!strcmp(lookup->dev_id, dev_id))
959 count++;
960 }
961
962 mutex_unlock(&reset_lookup_mutex);
963
964 if (count == 0)
965 count = -ENOENT;
966
967 return count;
968}
969
970/**
971 * reset_control_get_count - Count number of resets available with a device
972 *
973 * @dev: device for which to return the number of resets
974 *
975 * Returns positive reset count on success, or error number on failure and
976 * on count being zero.
977 */
978int reset_control_get_count(struct device *dev)
979{
980 if (dev->of_node)
981 return of_reset_control_get_count(dev->of_node);
982
983 return reset_control_get_count_from_lookup(dev);
984}
985EXPORT_SYMBOL_GPL(reset_control_get_count);