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/cleanup.h>
9#include <linux/device.h>
10#include <linux/err.h>
11#include <linux/export.h>
12#include <linux/kernel.h>
13#include <linux/kref.h>
14#include <linux/gpio/driver.h>
15#include <linux/gpio/machine.h>
16#include <linux/idr.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/acpi.h>
20#include <linux/platform_device.h>
21#include <linux/reset.h>
22#include <linux/reset-controller.h>
23#include <linux/slab.h>
24
25static DEFINE_MUTEX(reset_list_mutex);
26static LIST_HEAD(reset_controller_list);
27
28static DEFINE_MUTEX(reset_lookup_mutex);
29static LIST_HEAD(reset_lookup_list);
30
31/* Protects reset_gpio_lookup_list */
32static DEFINE_MUTEX(reset_gpio_lookup_mutex);
33static LIST_HEAD(reset_gpio_lookup_list);
34static DEFINE_IDA(reset_gpio_ida);
35
36/**
37 * struct reset_control - a reset control
38 * @rcdev: a pointer to the reset controller device
39 * this reset control belongs to
40 * @list: list entry for the rcdev's reset controller list
41 * @id: ID of the reset controller in the reset
42 * controller device
43 * @refcnt: Number of gets of this reset_control
44 * @acquired: Only one reset_control may be acquired for a given rcdev and id.
45 * @shared: Is this a shared (1), or an exclusive (0) reset_control?
46 * @array: Is this an array of reset controls (1)?
47 * @deassert_count: Number of times this reset line has been deasserted
48 * @triggered_count: Number of times this reset line has been reset. Currently
49 * only used for shared resets, which means that the value
50 * will be either 0 or 1.
51 */
52struct reset_control {
53 struct reset_controller_dev *rcdev;
54 struct list_head list;
55 unsigned int id;
56 struct kref refcnt;
57 bool acquired;
58 bool shared;
59 bool array;
60 atomic_t deassert_count;
61 atomic_t triggered_count;
62};
63
64/**
65 * struct reset_control_array - an array of reset controls
66 * @base: reset control for compatibility with reset control API functions
67 * @num_rstcs: number of reset controls
68 * @rstc: array of reset controls
69 */
70struct reset_control_array {
71 struct reset_control base;
72 unsigned int num_rstcs;
73 struct reset_control *rstc[] __counted_by(num_rstcs);
74};
75
76/**
77 * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
78 * @of_args: phandle to the reset controller with all the args like GPIO number
79 * @list: list entry for the reset_gpio_lookup_list
80 */
81struct reset_gpio_lookup {
82 struct of_phandle_args of_args;
83 struct list_head list;
84};
85
86static const char *rcdev_name(struct reset_controller_dev *rcdev)
87{
88 if (rcdev->dev)
89 return dev_name(dev: rcdev->dev);
90
91 if (rcdev->of_node)
92 return rcdev->of_node->full_name;
93
94 if (rcdev->of_args)
95 return rcdev->of_args->np->full_name;
96
97 return NULL;
98}
99
100/**
101 * of_reset_simple_xlate - translate reset_spec to the reset line number
102 * @rcdev: a pointer to the reset controller device
103 * @reset_spec: reset line specifier as found in the device tree
104 *
105 * This static translation function is used by default if of_xlate in
106 * :c:type:`reset_controller_dev` is not set. It is useful for all reset
107 * controllers with 1:1 mapping, where reset lines can be indexed by number
108 * without gaps.
109 */
110static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
111 const struct of_phandle_args *reset_spec)
112{
113 if (reset_spec->args[0] >= rcdev->nr_resets)
114 return -EINVAL;
115
116 return reset_spec->args[0];
117}
118
119/**
120 * reset_controller_register - register a reset controller device
121 * @rcdev: a pointer to the initialized reset controller device
122 */
123int reset_controller_register(struct reset_controller_dev *rcdev)
124{
125 if (rcdev->of_node && rcdev->of_args)
126 return -EINVAL;
127
128 if (!rcdev->of_xlate) {
129 rcdev->of_reset_n_cells = 1;
130 rcdev->of_xlate = of_reset_simple_xlate;
131 }
132
133 INIT_LIST_HEAD(list: &rcdev->reset_control_head);
134
135 mutex_lock(&reset_list_mutex);
136 list_add(new: &rcdev->list, head: &reset_controller_list);
137 mutex_unlock(lock: &reset_list_mutex);
138
139 return 0;
140}
141EXPORT_SYMBOL_GPL(reset_controller_register);
142
143/**
144 * reset_controller_unregister - unregister a reset controller device
145 * @rcdev: a pointer to the reset controller device
146 */
147void reset_controller_unregister(struct reset_controller_dev *rcdev)
148{
149 mutex_lock(&reset_list_mutex);
150 list_del(entry: &rcdev->list);
151 mutex_unlock(lock: &reset_list_mutex);
152}
153EXPORT_SYMBOL_GPL(reset_controller_unregister);
154
155static void devm_reset_controller_release(struct device *dev, void *res)
156{
157 reset_controller_unregister(*(struct reset_controller_dev **)res);
158}
159
160/**
161 * devm_reset_controller_register - resource managed reset_controller_register()
162 * @dev: device that is registering this reset controller
163 * @rcdev: a pointer to the initialized reset controller device
164 *
165 * Managed reset_controller_register(). For reset controllers registered by
166 * this function, reset_controller_unregister() is automatically called on
167 * driver detach. See reset_controller_register() for more information.
168 */
169int devm_reset_controller_register(struct device *dev,
170 struct reset_controller_dev *rcdev)
171{
172 struct reset_controller_dev **rcdevp;
173 int ret;
174
175 rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
176 GFP_KERNEL);
177 if (!rcdevp)
178 return -ENOMEM;
179
180 ret = reset_controller_register(rcdev);
181 if (ret) {
182 devres_free(res: rcdevp);
183 return ret;
184 }
185
186 *rcdevp = rcdev;
187 devres_add(dev, res: rcdevp);
188
189 return ret;
190}
191EXPORT_SYMBOL_GPL(devm_reset_controller_register);
192
193/**
194 * reset_controller_add_lookup - register a set of lookup entries
195 * @lookup: array of reset lookup entries
196 * @num_entries: number of entries in the lookup array
197 */
198void reset_controller_add_lookup(struct reset_control_lookup *lookup,
199 unsigned int num_entries)
200{
201 struct reset_control_lookup *entry;
202 unsigned int i;
203
204 mutex_lock(&reset_lookup_mutex);
205 for (i = 0; i < num_entries; i++) {
206 entry = &lookup[i];
207
208 if (!entry->dev_id || !entry->provider) {
209 pr_warn("%s(): reset lookup entry badly specified, skipping\n",
210 __func__);
211 continue;
212 }
213
214 list_add_tail(new: &entry->list, head: &reset_lookup_list);
215 }
216 mutex_unlock(lock: &reset_lookup_mutex);
217}
218EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
219
220static inline struct reset_control_array *
221rstc_to_array(struct reset_control *rstc) {
222 return container_of(rstc, struct reset_control_array, base);
223}
224
225static int reset_control_array_reset(struct reset_control_array *resets)
226{
227 int ret, i;
228
229 for (i = 0; i < resets->num_rstcs; i++) {
230 ret = reset_control_reset(rstc: resets->rstc[i]);
231 if (ret)
232 return ret;
233 }
234
235 return 0;
236}
237
238static int reset_control_array_rearm(struct reset_control_array *resets)
239{
240 struct reset_control *rstc;
241 int i;
242
243 for (i = 0; i < resets->num_rstcs; i++) {
244 rstc = resets->rstc[i];
245
246 if (!rstc)
247 continue;
248
249 if (WARN_ON(IS_ERR(rstc)))
250 return -EINVAL;
251
252 if (rstc->shared) {
253 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
254 return -EINVAL;
255 } else {
256 if (!rstc->acquired)
257 return -EPERM;
258 }
259 }
260
261 for (i = 0; i < resets->num_rstcs; i++) {
262 rstc = resets->rstc[i];
263
264 if (rstc && rstc->shared)
265 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
266 }
267
268 return 0;
269}
270
271static int reset_control_array_assert(struct reset_control_array *resets)
272{
273 int ret, i;
274
275 for (i = 0; i < resets->num_rstcs; i++) {
276 ret = reset_control_assert(rstc: resets->rstc[i]);
277 if (ret)
278 goto err;
279 }
280
281 return 0;
282
283err:
284 while (i--)
285 reset_control_deassert(rstc: resets->rstc[i]);
286 return ret;
287}
288
289static int reset_control_array_deassert(struct reset_control_array *resets)
290{
291 int ret, i;
292
293 for (i = 0; i < resets->num_rstcs; i++) {
294 ret = reset_control_deassert(rstc: resets->rstc[i]);
295 if (ret)
296 goto err;
297 }
298
299 return 0;
300
301err:
302 while (i--)
303 reset_control_assert(rstc: resets->rstc[i]);
304 return ret;
305}
306
307static int reset_control_array_acquire(struct reset_control_array *resets)
308{
309 unsigned int i;
310 int err;
311
312 for (i = 0; i < resets->num_rstcs; i++) {
313 err = reset_control_acquire(rstc: resets->rstc[i]);
314 if (err < 0)
315 goto release;
316 }
317
318 return 0;
319
320release:
321 while (i--)
322 reset_control_release(rstc: resets->rstc[i]);
323
324 return err;
325}
326
327static void reset_control_array_release(struct reset_control_array *resets)
328{
329 unsigned int i;
330
331 for (i = 0; i < resets->num_rstcs; i++)
332 reset_control_release(rstc: resets->rstc[i]);
333}
334
335static inline bool reset_control_is_array(struct reset_control *rstc)
336{
337 return rstc->array;
338}
339
340/**
341 * reset_control_reset - reset the controlled device
342 * @rstc: reset controller
343 *
344 * On a shared reset line the actual reset pulse is only triggered once for the
345 * lifetime of the reset_control instance: for all but the first caller this is
346 * a no-op.
347 * Consumers must not use reset_control_(de)assert on shared reset lines when
348 * reset_control_reset has been used.
349 *
350 * If rstc is NULL it is an optional reset and the function will just
351 * return 0.
352 */
353int reset_control_reset(struct reset_control *rstc)
354{
355 int ret;
356
357 if (!rstc)
358 return 0;
359
360 if (WARN_ON(IS_ERR(rstc)))
361 return -EINVAL;
362
363 if (reset_control_is_array(rstc))
364 return reset_control_array_reset(resets: rstc_to_array(rstc));
365
366 if (!rstc->rcdev->ops->reset)
367 return -ENOTSUPP;
368
369 if (rstc->shared) {
370 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
371 return -EINVAL;
372
373 if (atomic_inc_return(v: &rstc->triggered_count) != 1)
374 return 0;
375 } else {
376 if (!rstc->acquired)
377 return -EPERM;
378 }
379
380 ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
381 if (rstc->shared && ret)
382 atomic_dec(v: &rstc->triggered_count);
383
384 return ret;
385}
386EXPORT_SYMBOL_GPL(reset_control_reset);
387
388/**
389 * reset_control_bulk_reset - reset the controlled devices in order
390 * @num_rstcs: number of entries in rstcs array
391 * @rstcs: array of struct reset_control_bulk_data with reset controls set
392 *
393 * Issue a reset on all provided reset controls, in order.
394 *
395 * See also: reset_control_reset()
396 */
397int reset_control_bulk_reset(int num_rstcs,
398 struct reset_control_bulk_data *rstcs)
399{
400 int ret, i;
401
402 for (i = 0; i < num_rstcs; i++) {
403 ret = reset_control_reset(rstcs[i].rstc);
404 if (ret)
405 return ret;
406 }
407
408 return 0;
409}
410EXPORT_SYMBOL_GPL(reset_control_bulk_reset);
411
412/**
413 * reset_control_rearm - allow shared reset line to be re-triggered"
414 * @rstc: reset controller
415 *
416 * On a shared reset line the actual reset pulse is only triggered once for the
417 * lifetime of the reset_control instance, except if this call is used.
418 *
419 * Calls to this function must be balanced with calls to reset_control_reset,
420 * a warning is thrown in case triggered_count ever dips below 0.
421 *
422 * Consumers must not use reset_control_(de)assert on shared reset lines when
423 * reset_control_reset or reset_control_rearm have been used.
424 *
425 * If rstc is NULL the function will just return 0.
426 */
427int reset_control_rearm(struct reset_control *rstc)
428{
429 if (!rstc)
430 return 0;
431
432 if (WARN_ON(IS_ERR(rstc)))
433 return -EINVAL;
434
435 if (reset_control_is_array(rstc))
436 return reset_control_array_rearm(resets: rstc_to_array(rstc));
437
438 if (rstc->shared) {
439 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
440 return -EINVAL;
441
442 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
443 } else {
444 if (!rstc->acquired)
445 return -EPERM;
446 }
447
448 return 0;
449}
450EXPORT_SYMBOL_GPL(reset_control_rearm);
451
452/**
453 * reset_control_assert - asserts the reset line
454 * @rstc: reset controller
455 *
456 * Calling this on an exclusive reset controller guarantees that the reset
457 * will be asserted. When called on a shared reset controller the line may
458 * still be deasserted, as long as other users keep it so.
459 *
460 * For shared reset controls a driver cannot expect the hw's registers and
461 * internal state to be reset, but must be prepared for this to happen.
462 * Consumers must not use reset_control_reset on shared reset lines when
463 * reset_control_(de)assert has been used.
464 *
465 * If rstc is NULL it is an optional reset and the function will just
466 * return 0.
467 */
468int reset_control_assert(struct reset_control *rstc)
469{
470 if (!rstc)
471 return 0;
472
473 if (WARN_ON(IS_ERR(rstc)))
474 return -EINVAL;
475
476 if (reset_control_is_array(rstc))
477 return reset_control_array_assert(resets: rstc_to_array(rstc));
478
479 if (rstc->shared) {
480 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
481 return -EINVAL;
482
483 if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
484 return -EINVAL;
485
486 if (atomic_dec_return(v: &rstc->deassert_count) != 0)
487 return 0;
488
489 /*
490 * Shared reset controls allow the reset line to be in any state
491 * after this call, so doing nothing is a valid option.
492 */
493 if (!rstc->rcdev->ops->assert)
494 return 0;
495 } else {
496 /*
497 * If the reset controller does not implement .assert(), there
498 * is no way to guarantee that the reset line is asserted after
499 * this call.
500 */
501 if (!rstc->rcdev->ops->assert)
502 return -ENOTSUPP;
503
504 if (!rstc->acquired) {
505 WARN(1, "reset %s (ID: %u) is not acquired\n",
506 rcdev_name(rstc->rcdev), rstc->id);
507 return -EPERM;
508 }
509 }
510
511 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
512}
513EXPORT_SYMBOL_GPL(reset_control_assert);
514
515/**
516 * reset_control_bulk_assert - asserts the reset lines in order
517 * @num_rstcs: number of entries in rstcs array
518 * @rstcs: array of struct reset_control_bulk_data with reset controls set
519 *
520 * Assert the reset lines for all provided reset controls, in order.
521 * If an assertion fails, already asserted resets are deasserted again.
522 *
523 * See also: reset_control_assert()
524 */
525int reset_control_bulk_assert(int num_rstcs,
526 struct reset_control_bulk_data *rstcs)
527{
528 int ret, i;
529
530 for (i = 0; i < num_rstcs; i++) {
531 ret = reset_control_assert(rstcs[i].rstc);
532 if (ret)
533 goto err;
534 }
535
536 return 0;
537
538err:
539 while (i--)
540 reset_control_deassert(rstc: rstcs[i].rstc);
541 return ret;
542}
543EXPORT_SYMBOL_GPL(reset_control_bulk_assert);
544
545/**
546 * reset_control_deassert - deasserts the reset line
547 * @rstc: reset controller
548 *
549 * After calling this function, the reset is guaranteed to be deasserted.
550 * Consumers must not use reset_control_reset on shared reset lines when
551 * reset_control_(de)assert has been used.
552 *
553 * If rstc is NULL it is an optional reset and the function will just
554 * return 0.
555 */
556int reset_control_deassert(struct reset_control *rstc)
557{
558 if (!rstc)
559 return 0;
560
561 if (WARN_ON(IS_ERR(rstc)))
562 return -EINVAL;
563
564 if (reset_control_is_array(rstc))
565 return reset_control_array_deassert(resets: rstc_to_array(rstc));
566
567 if (rstc->shared) {
568 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
569 return -EINVAL;
570
571 if (atomic_inc_return(v: &rstc->deassert_count) != 1)
572 return 0;
573 } else {
574 if (!rstc->acquired) {
575 WARN(1, "reset %s (ID: %u) is not acquired\n",
576 rcdev_name(rstc->rcdev), rstc->id);
577 return -EPERM;
578 }
579 }
580
581 /*
582 * If the reset controller does not implement .deassert(), we assume
583 * that it handles self-deasserting reset lines via .reset(). In that
584 * case, the reset lines are deasserted by default. If that is not the
585 * case, the reset controller driver should implement .deassert() and
586 * return -ENOTSUPP.
587 */
588 if (!rstc->rcdev->ops->deassert)
589 return 0;
590
591 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
592}
593EXPORT_SYMBOL_GPL(reset_control_deassert);
594
595/**
596 * reset_control_bulk_deassert - deasserts the reset lines in reverse order
597 * @num_rstcs: number of entries in rstcs array
598 * @rstcs: array of struct reset_control_bulk_data with reset controls set
599 *
600 * Deassert the reset lines for all provided reset controls, in reverse order.
601 * If a deassertion fails, already deasserted resets are asserted again.
602 *
603 * See also: reset_control_deassert()
604 */
605int reset_control_bulk_deassert(int num_rstcs,
606 struct reset_control_bulk_data *rstcs)
607{
608 int ret, i;
609
610 for (i = num_rstcs - 1; i >= 0; i--) {
611 ret = reset_control_deassert(rstcs[i].rstc);
612 if (ret)
613 goto err;
614 }
615
616 return 0;
617
618err:
619 while (i < num_rstcs)
620 reset_control_assert(rstcs[i++].rstc);
621 return ret;
622}
623EXPORT_SYMBOL_GPL(reset_control_bulk_deassert);
624
625/**
626 * reset_control_status - returns a negative errno if not supported, a
627 * positive value if the reset line is asserted, or zero if the reset
628 * line is not asserted or if the desc is NULL (optional reset).
629 * @rstc: reset controller
630 */
631int reset_control_status(struct reset_control *rstc)
632{
633 if (!rstc)
634 return 0;
635
636 if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
637 return -EINVAL;
638
639 if (rstc->rcdev->ops->status)
640 return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
641
642 return -ENOTSUPP;
643}
644EXPORT_SYMBOL_GPL(reset_control_status);
645
646/**
647 * reset_control_acquire() - acquires a reset control for exclusive use
648 * @rstc: reset control
649 *
650 * This is used to explicitly acquire a reset control for exclusive use. Note
651 * that exclusive resets are requested as acquired by default. In order for a
652 * second consumer to be able to control the reset, the first consumer has to
653 * release it first. Typically the easiest way to achieve this is to call the
654 * reset_control_get_exclusive_released() to obtain an instance of the reset
655 * control. Such reset controls are not acquired by default.
656 *
657 * Consumers implementing shared access to an exclusive reset need to follow
658 * a specific protocol in order to work together. Before consumers can change
659 * a reset they must acquire exclusive access using reset_control_acquire().
660 * After they are done operating the reset, they must release exclusive access
661 * with a call to reset_control_release(). Consumers are not granted exclusive
662 * access to the reset as long as another consumer hasn't released a reset.
663 *
664 * See also: reset_control_release()
665 */
666int reset_control_acquire(struct reset_control *rstc)
667{
668 struct reset_control *rc;
669
670 if (!rstc)
671 return 0;
672
673 if (WARN_ON(IS_ERR(rstc)))
674 return -EINVAL;
675
676 if (reset_control_is_array(rstc))
677 return reset_control_array_acquire(resets: rstc_to_array(rstc));
678
679 mutex_lock(&reset_list_mutex);
680
681 if (rstc->acquired) {
682 mutex_unlock(lock: &reset_list_mutex);
683 return 0;
684 }
685
686 list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
687 if (rstc != rc && rstc->id == rc->id) {
688 if (rc->acquired) {
689 mutex_unlock(lock: &reset_list_mutex);
690 return -EBUSY;
691 }
692 }
693 }
694
695 rstc->acquired = true;
696
697 mutex_unlock(lock: &reset_list_mutex);
698 return 0;
699}
700EXPORT_SYMBOL_GPL(reset_control_acquire);
701
702/**
703 * reset_control_bulk_acquire - acquires reset controls for exclusive use
704 * @num_rstcs: number of entries in rstcs array
705 * @rstcs: array of struct reset_control_bulk_data with reset controls set
706 *
707 * This is used to explicitly acquire reset controls requested with
708 * reset_control_bulk_get_exclusive_release() for temporary exclusive use.
709 *
710 * See also: reset_control_acquire(), reset_control_bulk_release()
711 */
712int reset_control_bulk_acquire(int num_rstcs,
713 struct reset_control_bulk_data *rstcs)
714{
715 int ret, i;
716
717 for (i = 0; i < num_rstcs; i++) {
718 ret = reset_control_acquire(rstcs[i].rstc);
719 if (ret)
720 goto err;
721 }
722
723 return 0;
724
725err:
726 while (i--)
727 reset_control_release(rstc: rstcs[i].rstc);
728 return ret;
729}
730EXPORT_SYMBOL_GPL(reset_control_bulk_acquire);
731
732/**
733 * reset_control_release() - releases exclusive access to a reset control
734 * @rstc: reset control
735 *
736 * Releases exclusive access right to a reset control previously obtained by a
737 * call to reset_control_acquire(). Until a consumer calls this function, no
738 * other consumers will be granted exclusive access.
739 *
740 * See also: reset_control_acquire()
741 */
742void reset_control_release(struct reset_control *rstc)
743{
744 if (!rstc || WARN_ON(IS_ERR(rstc)))
745 return;
746
747 if (reset_control_is_array(rstc))
748 reset_control_array_release(resets: rstc_to_array(rstc));
749 else
750 rstc->acquired = false;
751}
752EXPORT_SYMBOL_GPL(reset_control_release);
753
754/**
755 * reset_control_bulk_release() - releases exclusive access to reset controls
756 * @num_rstcs: number of entries in rstcs array
757 * @rstcs: array of struct reset_control_bulk_data with reset controls set
758 *
759 * Releases exclusive access right to reset controls previously obtained by a
760 * call to reset_control_bulk_acquire().
761 *
762 * See also: reset_control_release(), reset_control_bulk_acquire()
763 */
764void reset_control_bulk_release(int num_rstcs,
765 struct reset_control_bulk_data *rstcs)
766{
767 int i;
768
769 for (i = 0; i < num_rstcs; i++)
770 reset_control_release(rstcs[i].rstc);
771}
772EXPORT_SYMBOL_GPL(reset_control_bulk_release);
773
774static struct reset_control *
775__reset_control_get_internal(struct reset_controller_dev *rcdev,
776 unsigned int index, enum reset_control_flags flags)
777{
778 bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED;
779 bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED;
780 struct reset_control *rstc;
781
782 lockdep_assert_held(&reset_list_mutex);
783
784 /* Expect callers to filter out OPTIONAL and DEASSERTED bits */
785 if (WARN_ON(flags & ~(RESET_CONTROL_FLAGS_BIT_SHARED |
786 RESET_CONTROL_FLAGS_BIT_ACQUIRED)))
787 return ERR_PTR(error: -EINVAL);
788
789 list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
790 if (rstc->id == index) {
791 /*
792 * Allow creating a secondary exclusive reset_control
793 * that is initially not acquired for an already
794 * controlled reset line.
795 */
796 if (!rstc->shared && !shared && !acquired)
797 break;
798
799 if (WARN_ON(!rstc->shared || !shared))
800 return ERR_PTR(error: -EBUSY);
801
802 kref_get(kref: &rstc->refcnt);
803 return rstc;
804 }
805 }
806
807 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
808 if (!rstc)
809 return ERR_PTR(error: -ENOMEM);
810
811 if (!try_module_get(module: rcdev->owner)) {
812 kfree(objp: rstc);
813 return ERR_PTR(error: -ENODEV);
814 }
815
816 rstc->rcdev = rcdev;
817 list_add(new: &rstc->list, head: &rcdev->reset_control_head);
818 rstc->id = index;
819 kref_init(kref: &rstc->refcnt);
820 rstc->acquired = acquired;
821 rstc->shared = shared;
822 get_device(dev: rcdev->dev);
823
824 return rstc;
825}
826
827static void __reset_control_release(struct kref *kref)
828{
829 struct reset_control *rstc = container_of(kref, struct reset_control,
830 refcnt);
831
832 lockdep_assert_held(&reset_list_mutex);
833
834 module_put(module: rstc->rcdev->owner);
835
836 list_del(entry: &rstc->list);
837 put_device(dev: rstc->rcdev->dev);
838 kfree(objp: rstc);
839}
840
841static void __reset_control_put_internal(struct reset_control *rstc)
842{
843 lockdep_assert_held(&reset_list_mutex);
844
845 if (IS_ERR_OR_NULL(ptr: rstc))
846 return;
847
848 kref_put(kref: &rstc->refcnt, release: __reset_control_release);
849}
850
851static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
852 unsigned int gpio,
853 unsigned int of_flags)
854{
855 const struct fwnode_handle *fwnode = of_fwnode_handle(np);
856 unsigned int lookup_flags;
857 const char *label_tmp;
858
859 /*
860 * Later we map GPIO flags between OF and Linux, however not all
861 * constants from include/dt-bindings/gpio/gpio.h and
862 * include/linux/gpio/machine.h match each other.
863 */
864 if (of_flags > GPIO_ACTIVE_LOW) {
865 pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
866 of_flags, gpio);
867 return -EINVAL;
868 }
869
870 struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
871 if (!gdev)
872 return -EPROBE_DEFER;
873
874 label_tmp = gpio_device_get_label(gdev);
875 if (!label_tmp)
876 return -EINVAL;
877
878 char *label __free(kfree) = kstrdup(s: label_tmp, GFP_KERNEL);
879 if (!label)
880 return -ENOMEM;
881
882 /* Size: one lookup entry plus sentinel */
883 struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
884 GFP_KERNEL);
885 if (!lookup)
886 return -ENOMEM;
887
888 lookup->dev_id = kasprintf(GFP_KERNEL, fmt: "reset-gpio.%d", id);
889 if (!lookup->dev_id)
890 return -ENOMEM;
891
892 lookup_flags = GPIO_PERSISTENT;
893 lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
894 lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
895 lookup_flags);
896
897 /* Not freed on success, because it is persisent subsystem data. */
898 gpiod_add_lookup_table(no_free_ptr(lookup));
899
900 return 0;
901}
902
903/*
904 * @args: phandle to the GPIO provider with all the args like GPIO number
905 */
906static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
907{
908 struct reset_gpio_lookup *rgpio_dev;
909 struct platform_device *pdev;
910 int id, ret;
911
912 /*
913 * Currently only #gpio-cells=2 is supported with the meaning of:
914 * args[0]: GPIO number
915 * args[1]: GPIO flags
916 * TODO: Handle other cases.
917 */
918 if (args->args_count != 2)
919 return -ENOENT;
920
921 /*
922 * Registering reset-gpio device might cause immediate
923 * bind, resulting in its probe() registering new reset controller thus
924 * taking reset_list_mutex lock via reset_controller_register().
925 */
926 lockdep_assert_not_held(&reset_list_mutex);
927
928 guard(mutex)(T: &reset_gpio_lookup_mutex);
929
930 list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
931 if (args->np == rgpio_dev->of_args.np) {
932 if (of_phandle_args_equal(a1: args, a2: &rgpio_dev->of_args))
933 return 0; /* Already on the list, done */
934 }
935 }
936
937 id = ida_alloc(ida: &reset_gpio_ida, GFP_KERNEL);
938 if (id < 0)
939 return id;
940
941 /* Not freed on success, because it is persisent subsystem data. */
942 rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
943 if (!rgpio_dev) {
944 ret = -ENOMEM;
945 goto err_ida_free;
946 }
947
948 ret = __reset_add_reset_gpio_lookup(id, np: args->np, gpio: args->args[0],
949 of_flags: args->args[1]);
950 if (ret < 0)
951 goto err_kfree;
952
953 rgpio_dev->of_args = *args;
954 /*
955 * We keep the device_node reference, but of_args.np is put at the end
956 * of __of_reset_control_get(), so get it one more time.
957 * Hold reference as long as rgpio_dev memory is valid.
958 */
959 of_node_get(node: rgpio_dev->of_args.np);
960 pdev = platform_device_register_data(NULL, name: "reset-gpio", id,
961 data: &rgpio_dev->of_args,
962 size: sizeof(rgpio_dev->of_args));
963 ret = PTR_ERR_OR_ZERO(ptr: pdev);
964 if (ret)
965 goto err_put;
966
967 list_add(new: &rgpio_dev->list, head: &reset_gpio_lookup_list);
968
969 return 0;
970
971err_put:
972 of_node_put(node: rgpio_dev->of_args.np);
973err_kfree:
974 kfree(objp: rgpio_dev);
975err_ida_free:
976 ida_free(&reset_gpio_ida, id);
977
978 return ret;
979}
980
981static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
982 bool gpio_fallback)
983{
984 struct reset_controller_dev *rcdev;
985
986 lockdep_assert_held(&reset_list_mutex);
987
988 list_for_each_entry(rcdev, &reset_controller_list, list) {
989 if (gpio_fallback) {
990 if (rcdev->of_args && of_phandle_args_equal(a1: args,
991 a2: rcdev->of_args))
992 return rcdev;
993 } else {
994 if (args->np == rcdev->of_node)
995 return rcdev;
996 }
997 }
998
999 return NULL;
1000}
1001
1002struct reset_control *
1003__of_reset_control_get(struct device_node *node, const char *id, int index,
1004 enum reset_control_flags flags)
1005{
1006 bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
1007 bool gpio_fallback = false;
1008 struct reset_control *rstc;
1009 struct reset_controller_dev *rcdev;
1010 struct of_phandle_args args;
1011 int rstc_id;
1012 int ret;
1013
1014 if (!node)
1015 return ERR_PTR(error: -EINVAL);
1016
1017 if (id) {
1018 index = of_property_match_string(np: node,
1019 propname: "reset-names", string: id);
1020 if (index == -EILSEQ)
1021 return ERR_PTR(error: index);
1022 if (index < 0)
1023 return optional ? NULL : ERR_PTR(error: -ENOENT);
1024 }
1025
1026 ret = of_parse_phandle_with_args(np: node, list_name: "resets", cells_name: "#reset-cells",
1027 index, out_args: &args);
1028 if (ret == -EINVAL)
1029 return ERR_PTR(error: ret);
1030 if (ret) {
1031 if (!IS_ENABLED(CONFIG_RESET_GPIO))
1032 return optional ? NULL : ERR_PTR(error: ret);
1033
1034 /*
1035 * There can be only one reset-gpio for regular devices, so
1036 * don't bother with the "reset-gpios" phandle index.
1037 */
1038 ret = of_parse_phandle_with_args(np: node, list_name: "reset-gpios", cells_name: "#gpio-cells",
1039 index: 0, out_args: &args);
1040 if (ret)
1041 return optional ? NULL : ERR_PTR(error: ret);
1042
1043 gpio_fallback = true;
1044
1045 ret = __reset_add_reset_gpio_device(args: &args);
1046 if (ret) {
1047 rstc = ERR_PTR(error: ret);
1048 goto out_put;
1049 }
1050 }
1051
1052 mutex_lock(&reset_list_mutex);
1053 rcdev = __reset_find_rcdev(args: &args, gpio_fallback);
1054 if (!rcdev) {
1055 rstc = ERR_PTR(error: -EPROBE_DEFER);
1056 goto out_unlock;
1057 }
1058
1059 if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
1060 rstc = ERR_PTR(error: -EINVAL);
1061 goto out_unlock;
1062 }
1063
1064 rstc_id = rcdev->of_xlate(rcdev, &args);
1065 if (rstc_id < 0) {
1066 rstc = ERR_PTR(error: rstc_id);
1067 goto out_unlock;
1068 }
1069
1070 flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL;
1071
1072 /* reset_list_mutex also protects the rcdev's reset_control list */
1073 rstc = __reset_control_get_internal(rcdev, index: rstc_id, flags);
1074
1075out_unlock:
1076 mutex_unlock(lock: &reset_list_mutex);
1077out_put:
1078 of_node_put(node: args.np);
1079
1080 return rstc;
1081}
1082EXPORT_SYMBOL_GPL(__of_reset_control_get);
1083
1084static struct reset_controller_dev *
1085__reset_controller_by_name(const char *name)
1086{
1087 struct reset_controller_dev *rcdev;
1088
1089 lockdep_assert_held(&reset_list_mutex);
1090
1091 list_for_each_entry(rcdev, &reset_controller_list, list) {
1092 if (!rcdev->dev)
1093 continue;
1094
1095 if (!strcmp(name, dev_name(dev: rcdev->dev)))
1096 return rcdev;
1097 }
1098
1099 return NULL;
1100}
1101
1102static struct reset_control *
1103__reset_control_get_from_lookup(struct device *dev, const char *con_id,
1104 enum reset_control_flags flags)
1105{
1106 bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
1107 const struct reset_control_lookup *lookup;
1108 struct reset_controller_dev *rcdev;
1109 const char *dev_id = dev_name(dev);
1110 struct reset_control *rstc = NULL;
1111
1112 mutex_lock(&reset_lookup_mutex);
1113
1114 list_for_each_entry(lookup, &reset_lookup_list, list) {
1115 if (strcmp(lookup->dev_id, dev_id))
1116 continue;
1117
1118 if ((!con_id && !lookup->con_id) ||
1119 ((con_id && lookup->con_id) &&
1120 !strcmp(con_id, lookup->con_id))) {
1121 mutex_lock(&reset_list_mutex);
1122 rcdev = __reset_controller_by_name(name: lookup->provider);
1123 if (!rcdev) {
1124 mutex_unlock(lock: &reset_list_mutex);
1125 mutex_unlock(lock: &reset_lookup_mutex);
1126 /* Reset provider may not be ready yet. */
1127 return ERR_PTR(error: -EPROBE_DEFER);
1128 }
1129
1130 flags &= ~RESET_CONTROL_FLAGS_BIT_OPTIONAL;
1131
1132 rstc = __reset_control_get_internal(rcdev,
1133 index: lookup->index,
1134 flags);
1135 mutex_unlock(lock: &reset_list_mutex);
1136 break;
1137 }
1138 }
1139
1140 mutex_unlock(lock: &reset_lookup_mutex);
1141
1142 if (!rstc)
1143 return optional ? NULL : ERR_PTR(error: -ENOENT);
1144
1145 return rstc;
1146}
1147
1148struct reset_control *__reset_control_get(struct device *dev, const char *id,
1149 int index, enum reset_control_flags flags)
1150{
1151 bool shared = flags & RESET_CONTROL_FLAGS_BIT_SHARED;
1152 bool acquired = flags & RESET_CONTROL_FLAGS_BIT_ACQUIRED;
1153
1154 if (WARN_ON(shared && acquired))
1155 return ERR_PTR(error: -EINVAL);
1156
1157 if (dev->of_node)
1158 return __of_reset_control_get(dev->of_node, id, index, flags);
1159
1160 return __reset_control_get_from_lookup(dev, con_id: id, flags);
1161}
1162EXPORT_SYMBOL_GPL(__reset_control_get);
1163
1164int __reset_control_bulk_get(struct device *dev, int num_rstcs,
1165 struct reset_control_bulk_data *rstcs,
1166 enum reset_control_flags flags)
1167{
1168 int ret, i;
1169
1170 for (i = 0; i < num_rstcs; i++) {
1171 rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0, flags);
1172 if (IS_ERR(ptr: rstcs[i].rstc)) {
1173 ret = PTR_ERR(ptr: rstcs[i].rstc);
1174 goto err;
1175 }
1176 }
1177
1178 return 0;
1179
1180err:
1181 mutex_lock(&reset_list_mutex);
1182 while (i--)
1183 __reset_control_put_internal(rstc: rstcs[i].rstc);
1184 mutex_unlock(lock: &reset_list_mutex);
1185 return ret;
1186}
1187EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
1188
1189static void reset_control_array_put(struct reset_control_array *resets)
1190{
1191 int i;
1192
1193 mutex_lock(&reset_list_mutex);
1194 for (i = 0; i < resets->num_rstcs; i++)
1195 __reset_control_put_internal(rstc: resets->rstc[i]);
1196 mutex_unlock(lock: &reset_list_mutex);
1197 kfree(objp: resets);
1198}
1199
1200/**
1201 * reset_control_put - free the reset controller
1202 * @rstc: reset controller
1203 */
1204void reset_control_put(struct reset_control *rstc)
1205{
1206 if (IS_ERR_OR_NULL(ptr: rstc))
1207 return;
1208
1209 if (reset_control_is_array(rstc)) {
1210 reset_control_array_put(resets: rstc_to_array(rstc));
1211 return;
1212 }
1213
1214 mutex_lock(&reset_list_mutex);
1215 __reset_control_put_internal(rstc);
1216 mutex_unlock(lock: &reset_list_mutex);
1217}
1218EXPORT_SYMBOL_GPL(reset_control_put);
1219
1220/**
1221 * reset_control_bulk_put - free the reset controllers
1222 * @num_rstcs: number of entries in rstcs array
1223 * @rstcs: array of struct reset_control_bulk_data with reset controls set
1224 */
1225void reset_control_bulk_put(int num_rstcs, struct reset_control_bulk_data *rstcs)
1226{
1227 mutex_lock(&reset_list_mutex);
1228 while (num_rstcs--)
1229 __reset_control_put_internal(rstc: rstcs[num_rstcs].rstc);
1230 mutex_unlock(lock: &reset_list_mutex);
1231}
1232EXPORT_SYMBOL_GPL(reset_control_bulk_put);
1233
1234static void devm_reset_control_release(struct device *dev, void *res)
1235{
1236 reset_control_put(*(struct reset_control **)res);
1237}
1238
1239static void devm_reset_control_release_deasserted(struct device *dev, void *res)
1240{
1241 struct reset_control *rstc = *(struct reset_control **)res;
1242
1243 reset_control_assert(rstc);
1244 reset_control_put(rstc);
1245}
1246
1247struct reset_control *
1248__devm_reset_control_get(struct device *dev, const char *id, int index,
1249 enum reset_control_flags flags)
1250{
1251 struct reset_control **ptr, *rstc;
1252 bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED;
1253
1254 ptr = devres_alloc(deasserted ? devm_reset_control_release_deasserted :
1255 devm_reset_control_release, sizeof(*ptr),
1256 GFP_KERNEL);
1257 if (!ptr)
1258 return ERR_PTR(error: -ENOMEM);
1259
1260 flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED;
1261
1262 rstc = __reset_control_get(dev, id, index, flags);
1263 if (IS_ERR_OR_NULL(ptr: rstc)) {
1264 devres_free(res: ptr);
1265 return rstc;
1266 }
1267
1268 if (deasserted) {
1269 int ret;
1270
1271 ret = reset_control_deassert(rstc);
1272 if (ret) {
1273 reset_control_put(rstc);
1274 devres_free(res: ptr);
1275 return ERR_PTR(error: ret);
1276 }
1277 }
1278
1279 *ptr = rstc;
1280 devres_add(dev, res: ptr);
1281
1282 return rstc;
1283}
1284EXPORT_SYMBOL_GPL(__devm_reset_control_get);
1285
1286struct reset_control_bulk_devres {
1287 int num_rstcs;
1288 struct reset_control_bulk_data *rstcs;
1289};
1290
1291static void devm_reset_control_bulk_release(struct device *dev, void *res)
1292{
1293 struct reset_control_bulk_devres *devres = res;
1294
1295 reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
1296}
1297
1298static void devm_reset_control_bulk_release_deasserted(struct device *dev, void *res)
1299{
1300 struct reset_control_bulk_devres *devres = res;
1301
1302 reset_control_bulk_assert(devres->num_rstcs, devres->rstcs);
1303 reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
1304}
1305
1306int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs,
1307 struct reset_control_bulk_data *rstcs,
1308 enum reset_control_flags flags)
1309{
1310 struct reset_control_bulk_devres *ptr;
1311 bool deasserted = flags & RESET_CONTROL_FLAGS_BIT_DEASSERTED;
1312 int ret;
1313
1314 ptr = devres_alloc(deasserted ? devm_reset_control_bulk_release_deasserted :
1315 devm_reset_control_bulk_release, sizeof(*ptr),
1316 GFP_KERNEL);
1317 if (!ptr)
1318 return -ENOMEM;
1319
1320 flags &= ~RESET_CONTROL_FLAGS_BIT_DEASSERTED;
1321
1322 ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, flags);
1323 if (ret < 0) {
1324 devres_free(res: ptr);
1325 return ret;
1326 }
1327
1328 if (deasserted) {
1329 ret = reset_control_bulk_deassert(num_rstcs, rstcs);
1330 if (ret) {
1331 reset_control_bulk_put(num_rstcs, rstcs);
1332 devres_free(res: ptr);
1333 return ret;
1334 }
1335 }
1336
1337 ptr->num_rstcs = num_rstcs;
1338 ptr->rstcs = rstcs;
1339 devres_add(dev, res: ptr);
1340
1341 return 0;
1342}
1343EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get);
1344
1345/**
1346 * __device_reset - find reset controller associated with the device
1347 * and perform reset
1348 * @dev: device to be reset by the controller
1349 * @optional: whether it is optional to reset the device
1350 *
1351 * Convenience wrapper for __reset_control_get() and reset_control_reset().
1352 * This is useful for the common case of devices with single, dedicated reset
1353 * lines. _RST firmware method will be called for devices with ACPI.
1354 */
1355int __device_reset(struct device *dev, bool optional)
1356{
1357 enum reset_control_flags flags;
1358 struct reset_control *rstc;
1359 int ret;
1360
1361#ifdef CONFIG_ACPI
1362 acpi_handle handle = ACPI_HANDLE(dev);
1363
1364 if (handle) {
1365 if (!acpi_has_method(handle, name: "_RST"))
1366 return optional ? 0 : -ENOENT;
1367 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL,
1368 NULL)))
1369 return -EIO;
1370 }
1371#endif
1372
1373 flags = optional ? RESET_CONTROL_OPTIONAL_EXCLUSIVE : RESET_CONTROL_EXCLUSIVE;
1374 rstc = __reset_control_get(dev, NULL, 0, flags);
1375 if (IS_ERR(ptr: rstc))
1376 return PTR_ERR(ptr: rstc);
1377
1378 ret = reset_control_reset(rstc);
1379
1380 reset_control_put(rstc);
1381
1382 return ret;
1383}
1384EXPORT_SYMBOL_GPL(__device_reset);
1385
1386/*
1387 * APIs to manage an array of reset controls.
1388 */
1389
1390/**
1391 * of_reset_control_get_count - Count number of resets available with a device
1392 *
1393 * @node: device node that contains 'resets'.
1394 *
1395 * Returns positive reset count on success, or error number on failure and
1396 * on count being zero.
1397 */
1398static int of_reset_control_get_count(struct device_node *node)
1399{
1400 int count;
1401
1402 if (!node)
1403 return -EINVAL;
1404
1405 count = of_count_phandle_with_args(np: node, list_name: "resets", cells_name: "#reset-cells");
1406 if (count == 0)
1407 count = -ENOENT;
1408
1409 return count;
1410}
1411
1412/**
1413 * of_reset_control_array_get - Get a list of reset controls using
1414 * device node.
1415 *
1416 * @np: device node for the device that requests the reset controls array
1417 * @flags: whether reset controls are shared, optional, acquired
1418 *
1419 * Returns pointer to allocated reset_control on success or error on failure
1420 */
1421struct reset_control *
1422of_reset_control_array_get(struct device_node *np, enum reset_control_flags flags)
1423{
1424 bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
1425 struct reset_control_array *resets;
1426 struct reset_control *rstc;
1427 int num, i;
1428
1429 num = of_reset_control_get_count(node: np);
1430 if (num < 0)
1431 return optional ? NULL : ERR_PTR(error: num);
1432
1433 resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
1434 if (!resets)
1435 return ERR_PTR(error: -ENOMEM);
1436 resets->num_rstcs = num;
1437
1438 for (i = 0; i < num; i++) {
1439 rstc = __of_reset_control_get(np, NULL, i, flags);
1440 if (IS_ERR(ptr: rstc))
1441 goto err_rst;
1442 resets->rstc[i] = rstc;
1443 }
1444 resets->base.array = true;
1445
1446 return &resets->base;
1447
1448err_rst:
1449 mutex_lock(&reset_list_mutex);
1450 while (--i >= 0)
1451 __reset_control_put_internal(rstc: resets->rstc[i]);
1452 mutex_unlock(lock: &reset_list_mutex);
1453
1454 kfree(objp: resets);
1455
1456 return rstc;
1457}
1458EXPORT_SYMBOL_GPL(of_reset_control_array_get);
1459
1460/**
1461 * devm_reset_control_array_get - Resource managed reset control array get
1462 *
1463 * @dev: device that requests the list of reset controls
1464 * @flags: whether reset controls are shared, optional, acquired
1465 *
1466 * The reset control array APIs are intended for a list of resets
1467 * that just have to be asserted or deasserted, without any
1468 * requirements on the order.
1469 *
1470 * Returns pointer to allocated reset_control on success or error on failure
1471 */
1472struct reset_control *
1473devm_reset_control_array_get(struct device *dev, enum reset_control_flags flags)
1474{
1475 struct reset_control **ptr, *rstc;
1476
1477 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1478 GFP_KERNEL);
1479 if (!ptr)
1480 return ERR_PTR(error: -ENOMEM);
1481
1482 rstc = of_reset_control_array_get(dev->of_node, flags);
1483 if (IS_ERR_OR_NULL(ptr: rstc)) {
1484 devres_free(res: ptr);
1485 return rstc;
1486 }
1487
1488 *ptr = rstc;
1489 devres_add(dev, res: ptr);
1490
1491 return rstc;
1492}
1493EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
1494
1495static int reset_control_get_count_from_lookup(struct device *dev)
1496{
1497 const struct reset_control_lookup *lookup;
1498 const char *dev_id;
1499 int count = 0;
1500
1501 if (!dev)
1502 return -EINVAL;
1503
1504 dev_id = dev_name(dev);
1505 mutex_lock(&reset_lookup_mutex);
1506
1507 list_for_each_entry(lookup, &reset_lookup_list, list) {
1508 if (!strcmp(lookup->dev_id, dev_id))
1509 count++;
1510 }
1511
1512 mutex_unlock(lock: &reset_lookup_mutex);
1513
1514 if (count == 0)
1515 count = -ENOENT;
1516
1517 return count;
1518}
1519
1520/**
1521 * reset_control_get_count - Count number of resets available with a device
1522 *
1523 * @dev: device for which to return the number of resets
1524 *
1525 * Returns positive reset count on success, or error number on failure and
1526 * on count being zero.
1527 */
1528int reset_control_get_count(struct device *dev)
1529{
1530 if (dev->of_node)
1531 return of_reset_control_get_count(node: dev->of_node);
1532
1533 return reset_control_get_count_from_lookup(dev);
1534}
1535EXPORT_SYMBOL_GPL(reset_control_get_count);
1536

source code of linux/drivers/reset/core.c