1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Reset Controller framework
5 * Copyright 2013 Philipp Zabel, Pengutronix
7 #include <linux/atomic.h>
8 #include <linux/device.h>
10 #include <linux/export.h>
11 #include <linux/kernel.h>
12 #include <linux/kref.h>
13 #include <linux/module.h>
15 #include <linux/reset.h>
16 #include <linux/reset-controller.h>
17 #include <linux/slab.h>
19 static DEFINE_MUTEX(reset_list_mutex);
20 static LIST_HEAD(reset_controller_list);
22 static DEFINE_MUTEX(reset_lookup_mutex);
23 static LIST_HEAD(reset_lookup_list);
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
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 * @array: Is this an array of reset controls (1)?
36 * @deassert_count: Number of times this reset line has been deasserted
37 * @triggered_count: Number of times this reset line has been reset. Currently
38 * only used for shared resets, which means that the value
39 * will be either 0 or 1.
41 struct reset_control {
42 struct reset_controller_dev *rcdev;
43 struct list_head list;
49 atomic_t deassert_count;
50 atomic_t triggered_count;
54 * struct reset_control_array - an array of reset controls
55 * @base: reset control for compatibility with reset control API functions
56 * @num_rstcs: number of reset controls
57 * @rstc: array of reset controls
59 struct reset_control_array {
60 struct reset_control base;
61 unsigned int num_rstcs;
62 struct reset_control *rstc[];
65 static const char *rcdev_name(struct reset_controller_dev *rcdev)
68 return dev_name(rcdev->dev);
71 return rcdev->of_node->full_name;
77 * of_reset_simple_xlate - translate reset_spec to the reset line number
78 * @rcdev: a pointer to the reset controller device
79 * @reset_spec: reset line specifier as found in the device tree
81 * This static translation function is used by default if of_xlate in
82 * :c:type:`reset_controller_dev` is not set. It is useful for all reset
83 * controllers with 1:1 mapping, where reset lines can be indexed by number
86 static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
87 const struct of_phandle_args *reset_spec)
89 if (reset_spec->args[0] >= rcdev->nr_resets)
92 return reset_spec->args[0];
96 * reset_controller_register - register a reset controller device
97 * @rcdev: a pointer to the initialized reset controller device
99 int reset_controller_register(struct reset_controller_dev *rcdev)
101 if (!rcdev->of_xlate) {
102 rcdev->of_reset_n_cells = 1;
103 rcdev->of_xlate = of_reset_simple_xlate;
106 INIT_LIST_HEAD(&rcdev->reset_control_head);
108 mutex_lock(&reset_list_mutex);
109 list_add(&rcdev->list, &reset_controller_list);
110 mutex_unlock(&reset_list_mutex);
114 EXPORT_SYMBOL_GPL(reset_controller_register);
117 * reset_controller_unregister - unregister a reset controller device
118 * @rcdev: a pointer to the reset controller device
120 void reset_controller_unregister(struct reset_controller_dev *rcdev)
122 mutex_lock(&reset_list_mutex);
123 list_del(&rcdev->list);
124 mutex_unlock(&reset_list_mutex);
126 EXPORT_SYMBOL_GPL(reset_controller_unregister);
128 static void devm_reset_controller_release(struct device *dev, void *res)
130 reset_controller_unregister(*(struct reset_controller_dev **)res);
134 * devm_reset_controller_register - resource managed reset_controller_register()
135 * @dev: device that is registering this reset controller
136 * @rcdev: a pointer to the initialized reset controller device
138 * Managed reset_controller_register(). For reset controllers registered by
139 * this function, reset_controller_unregister() is automatically called on
140 * driver detach. See reset_controller_register() for more information.
142 int devm_reset_controller_register(struct device *dev,
143 struct reset_controller_dev *rcdev)
145 struct reset_controller_dev **rcdevp;
148 rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
153 ret = reset_controller_register(rcdev);
160 devres_add(dev, rcdevp);
164 EXPORT_SYMBOL_GPL(devm_reset_controller_register);
167 * reset_controller_add_lookup - register a set of lookup entries
168 * @lookup: array of reset lookup entries
169 * @num_entries: number of entries in the lookup array
171 void reset_controller_add_lookup(struct reset_control_lookup *lookup,
172 unsigned int num_entries)
174 struct reset_control_lookup *entry;
177 mutex_lock(&reset_lookup_mutex);
178 for (i = 0; i < num_entries; i++) {
181 if (!entry->dev_id || !entry->provider) {
182 pr_warn("%s(): reset lookup entry badly specified, skipping\n",
187 list_add_tail(&entry->list, &reset_lookup_list);
189 mutex_unlock(&reset_lookup_mutex);
191 EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
193 static inline struct reset_control_array *
194 rstc_to_array(struct reset_control *rstc) {
195 return container_of(rstc, struct reset_control_array, base);
198 static int reset_control_array_reset(struct reset_control_array *resets)
202 for (i = 0; i < resets->num_rstcs; i++) {
203 ret = reset_control_reset(resets->rstc[i]);
211 static int reset_control_array_rearm(struct reset_control_array *resets)
213 struct reset_control *rstc;
216 for (i = 0; i < resets->num_rstcs; i++) {
217 rstc = resets->rstc[i];
222 if (WARN_ON(IS_ERR(rstc)))
226 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
234 for (i = 0; i < resets->num_rstcs; i++) {
235 rstc = resets->rstc[i];
237 if (rstc && rstc->shared)
238 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
244 static int reset_control_array_assert(struct reset_control_array *resets)
248 for (i = 0; i < resets->num_rstcs; i++) {
249 ret = reset_control_assert(resets->rstc[i]);
258 reset_control_deassert(resets->rstc[i]);
262 static int reset_control_array_deassert(struct reset_control_array *resets)
266 for (i = 0; i < resets->num_rstcs; i++) {
267 ret = reset_control_deassert(resets->rstc[i]);
276 reset_control_assert(resets->rstc[i]);
280 static int reset_control_array_acquire(struct reset_control_array *resets)
285 for (i = 0; i < resets->num_rstcs; i++) {
286 err = reset_control_acquire(resets->rstc[i]);
295 reset_control_release(resets->rstc[i]);
300 static void reset_control_array_release(struct reset_control_array *resets)
304 for (i = 0; i < resets->num_rstcs; i++)
305 reset_control_release(resets->rstc[i]);
308 static inline bool reset_control_is_array(struct reset_control *rstc)
314 * reset_control_reset - reset the controlled device
315 * @rstc: reset controller
317 * On a shared reset line the actual reset pulse is only triggered once for the
318 * lifetime of the reset_control instance: for all but the first caller this is
320 * Consumers must not use reset_control_(de)assert on shared reset lines when
321 * reset_control_reset has been used.
323 * If rstc is NULL it is an optional reset and the function will just
326 int reset_control_reset(struct reset_control *rstc)
333 if (WARN_ON(IS_ERR(rstc)))
336 if (reset_control_is_array(rstc))
337 return reset_control_array_reset(rstc_to_array(rstc));
339 if (!rstc->rcdev->ops->reset)
343 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
346 if (atomic_inc_return(&rstc->triggered_count) != 1)
353 ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
354 if (rstc->shared && ret)
355 atomic_dec(&rstc->triggered_count);
359 EXPORT_SYMBOL_GPL(reset_control_reset);
362 * reset_control_rearm - allow shared reset line to be re-triggered"
363 * @rstc: reset controller
365 * On a shared reset line the actual reset pulse is only triggered once for the
366 * lifetime of the reset_control instance, except if this call is used.
368 * Calls to this function must be balanced with calls to reset_control_reset,
369 * a warning is thrown in case triggered_count ever dips below 0.
371 * Consumers must not use reset_control_(de)assert on shared reset lines when
372 * reset_control_reset or reset_control_rearm have been used.
374 * If rstc is NULL the function will just return 0.
376 int reset_control_rearm(struct reset_control *rstc)
381 if (WARN_ON(IS_ERR(rstc)))
384 if (reset_control_is_array(rstc))
385 return reset_control_array_rearm(rstc_to_array(rstc));
388 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
391 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
399 EXPORT_SYMBOL_GPL(reset_control_rearm);
402 * reset_control_assert - asserts the reset line
403 * @rstc: reset controller
405 * Calling this on an exclusive reset controller guarantees that the reset
406 * will be asserted. When called on a shared reset controller the line may
407 * still be deasserted, as long as other users keep it so.
409 * For shared reset controls a driver cannot expect the hw's registers and
410 * internal state to be reset, but must be prepared for this to happen.
411 * Consumers must not use reset_control_reset on shared reset lines when
412 * reset_control_(de)assert has been used.
414 * If rstc is NULL it is an optional reset and the function will just
417 int reset_control_assert(struct reset_control *rstc)
422 if (WARN_ON(IS_ERR(rstc)))
425 if (reset_control_is_array(rstc))
426 return reset_control_array_assert(rstc_to_array(rstc));
429 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
432 if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
435 if (atomic_dec_return(&rstc->deassert_count) != 0)
439 * Shared reset controls allow the reset line to be in any state
440 * after this call, so doing nothing is a valid option.
442 if (!rstc->rcdev->ops->assert)
446 * If the reset controller does not implement .assert(), there
447 * is no way to guarantee that the reset line is asserted after
450 if (!rstc->rcdev->ops->assert)
453 if (!rstc->acquired) {
454 WARN(1, "reset %s (ID: %u) is not acquired\n",
455 rcdev_name(rstc->rcdev), rstc->id);
460 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
462 EXPORT_SYMBOL_GPL(reset_control_assert);
465 * reset_control_deassert - deasserts the reset line
466 * @rstc: reset controller
468 * After calling this function, the reset is guaranteed to be deasserted.
469 * Consumers must not use reset_control_reset on shared reset lines when
470 * reset_control_(de)assert has been used.
472 * If rstc is NULL it is an optional reset and the function will just
475 int reset_control_deassert(struct reset_control *rstc)
480 if (WARN_ON(IS_ERR(rstc)))
483 if (reset_control_is_array(rstc))
484 return reset_control_array_deassert(rstc_to_array(rstc));
487 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
490 if (atomic_inc_return(&rstc->deassert_count) != 1)
493 if (!rstc->acquired) {
494 WARN(1, "reset %s (ID: %u) is not acquired\n",
495 rcdev_name(rstc->rcdev), rstc->id);
501 * If the reset controller does not implement .deassert(), we assume
502 * that it handles self-deasserting reset lines via .reset(). In that
503 * case, the reset lines are deasserted by default. If that is not the
504 * case, the reset controller driver should implement .deassert() and
507 if (!rstc->rcdev->ops->deassert)
510 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
512 EXPORT_SYMBOL_GPL(reset_control_deassert);
515 * reset_control_status - returns a negative errno if not supported, a
516 * positive value if the reset line is asserted, or zero if the reset
517 * line is not asserted or if the desc is NULL (optional reset).
518 * @rstc: reset controller
520 int reset_control_status(struct reset_control *rstc)
525 if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
528 if (rstc->rcdev->ops->status)
529 return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
533 EXPORT_SYMBOL_GPL(reset_control_status);
536 * reset_control_acquire() - acquires a reset control for exclusive use
537 * @rstc: reset control
539 * This is used to explicitly acquire a reset control for exclusive use. Note
540 * that exclusive resets are requested as acquired by default. In order for a
541 * second consumer to be able to control the reset, the first consumer has to
542 * release it first. Typically the easiest way to achieve this is to call the
543 * reset_control_get_exclusive_released() to obtain an instance of the reset
544 * control. Such reset controls are not acquired by default.
546 * Consumers implementing shared access to an exclusive reset need to follow
547 * a specific protocol in order to work together. Before consumers can change
548 * a reset they must acquire exclusive access using reset_control_acquire().
549 * After they are done operating the reset, they must release exclusive access
550 * with a call to reset_control_release(). Consumers are not granted exclusive
551 * access to the reset as long as another consumer hasn't released a reset.
553 * See also: reset_control_release()
555 int reset_control_acquire(struct reset_control *rstc)
557 struct reset_control *rc;
562 if (WARN_ON(IS_ERR(rstc)))
565 if (reset_control_is_array(rstc))
566 return reset_control_array_acquire(rstc_to_array(rstc));
568 mutex_lock(&reset_list_mutex);
570 if (rstc->acquired) {
571 mutex_unlock(&reset_list_mutex);
575 list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
576 if (rstc != rc && rstc->id == rc->id) {
578 mutex_unlock(&reset_list_mutex);
584 rstc->acquired = true;
586 mutex_unlock(&reset_list_mutex);
589 EXPORT_SYMBOL_GPL(reset_control_acquire);
592 * reset_control_release() - releases exclusive access to a reset control
593 * @rstc: reset control
595 * Releases exclusive access right to a reset control previously obtained by a
596 * call to reset_control_acquire(). Until a consumer calls this function, no
597 * other consumers will be granted exclusive access.
599 * See also: reset_control_acquire()
601 void reset_control_release(struct reset_control *rstc)
603 if (!rstc || WARN_ON(IS_ERR(rstc)))
606 if (reset_control_is_array(rstc))
607 reset_control_array_release(rstc_to_array(rstc));
609 rstc->acquired = false;
611 EXPORT_SYMBOL_GPL(reset_control_release);
613 static struct reset_control *__reset_control_get_internal(
614 struct reset_controller_dev *rcdev,
615 unsigned int index, bool shared, bool acquired)
617 struct reset_control *rstc;
619 lockdep_assert_held(&reset_list_mutex);
621 list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
622 if (rstc->id == index) {
624 * Allow creating a secondary exclusive reset_control
625 * that is initially not acquired for an already
626 * controlled reset line.
628 if (!rstc->shared && !shared && !acquired)
631 if (WARN_ON(!rstc->shared || !shared))
632 return ERR_PTR(-EBUSY);
634 kref_get(&rstc->refcnt);
639 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
641 return ERR_PTR(-ENOMEM);
643 try_module_get(rcdev->owner);
646 list_add(&rstc->list, &rcdev->reset_control_head);
648 kref_init(&rstc->refcnt);
649 rstc->acquired = acquired;
650 rstc->shared = shared;
655 static void __reset_control_release(struct kref *kref)
657 struct reset_control *rstc = container_of(kref, struct reset_control,
660 lockdep_assert_held(&reset_list_mutex);
662 module_put(rstc->rcdev->owner);
664 list_del(&rstc->list);
668 static void __reset_control_put_internal(struct reset_control *rstc)
670 lockdep_assert_held(&reset_list_mutex);
672 kref_put(&rstc->refcnt, __reset_control_release);
675 struct reset_control *__of_reset_control_get(struct device_node *node,
676 const char *id, int index, bool shared,
677 bool optional, bool acquired)
679 struct reset_control *rstc;
680 struct reset_controller_dev *r, *rcdev;
681 struct of_phandle_args args;
686 return ERR_PTR(-EINVAL);
689 index = of_property_match_string(node,
691 if (index == -EILSEQ)
692 return ERR_PTR(index);
694 return optional ? NULL : ERR_PTR(-ENOENT);
697 ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
702 return optional ? NULL : ERR_PTR(ret);
704 mutex_lock(&reset_list_mutex);
706 list_for_each_entry(r, &reset_controller_list, list) {
707 if (args.np == r->of_node) {
714 rstc = ERR_PTR(-EPROBE_DEFER);
718 if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
719 rstc = ERR_PTR(-EINVAL);
723 rstc_id = rcdev->of_xlate(rcdev, &args);
725 rstc = ERR_PTR(rstc_id);
729 /* reset_list_mutex also protects the rcdev's reset_control list */
730 rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
733 mutex_unlock(&reset_list_mutex);
734 of_node_put(args.np);
738 EXPORT_SYMBOL_GPL(__of_reset_control_get);
740 static struct reset_controller_dev *
741 __reset_controller_by_name(const char *name)
743 struct reset_controller_dev *rcdev;
745 lockdep_assert_held(&reset_list_mutex);
747 list_for_each_entry(rcdev, &reset_controller_list, list) {
751 if (!strcmp(name, dev_name(rcdev->dev)))
758 static struct reset_control *
759 __reset_control_get_from_lookup(struct device *dev, const char *con_id,
760 bool shared, bool optional, bool acquired)
762 const struct reset_control_lookup *lookup;
763 struct reset_controller_dev *rcdev;
764 const char *dev_id = dev_name(dev);
765 struct reset_control *rstc = NULL;
767 mutex_lock(&reset_lookup_mutex);
769 list_for_each_entry(lookup, &reset_lookup_list, list) {
770 if (strcmp(lookup->dev_id, dev_id))
773 if ((!con_id && !lookup->con_id) ||
774 ((con_id && lookup->con_id) &&
775 !strcmp(con_id, lookup->con_id))) {
776 mutex_lock(&reset_list_mutex);
777 rcdev = __reset_controller_by_name(lookup->provider);
779 mutex_unlock(&reset_list_mutex);
780 mutex_unlock(&reset_lookup_mutex);
781 /* Reset provider may not be ready yet. */
782 return ERR_PTR(-EPROBE_DEFER);
785 rstc = __reset_control_get_internal(rcdev,
788 mutex_unlock(&reset_list_mutex);
793 mutex_unlock(&reset_lookup_mutex);
796 return optional ? NULL : ERR_PTR(-ENOENT);
801 struct reset_control *__reset_control_get(struct device *dev, const char *id,
802 int index, bool shared, bool optional,
805 if (WARN_ON(shared && acquired))
806 return ERR_PTR(-EINVAL);
809 return __of_reset_control_get(dev->of_node, id, index, shared,
812 return __reset_control_get_from_lookup(dev, id, shared, optional,
815 EXPORT_SYMBOL_GPL(__reset_control_get);
817 static void reset_control_array_put(struct reset_control_array *resets)
821 mutex_lock(&reset_list_mutex);
822 for (i = 0; i < resets->num_rstcs; i++)
823 __reset_control_put_internal(resets->rstc[i]);
824 mutex_unlock(&reset_list_mutex);
829 * reset_control_put - free the reset controller
830 * @rstc: reset controller
832 void reset_control_put(struct reset_control *rstc)
834 if (IS_ERR_OR_NULL(rstc))
837 if (reset_control_is_array(rstc)) {
838 reset_control_array_put(rstc_to_array(rstc));
842 mutex_lock(&reset_list_mutex);
843 __reset_control_put_internal(rstc);
844 mutex_unlock(&reset_list_mutex);
846 EXPORT_SYMBOL_GPL(reset_control_put);
848 static void devm_reset_control_release(struct device *dev, void *res)
850 reset_control_put(*(struct reset_control **)res);
853 struct reset_control *__devm_reset_control_get(struct device *dev,
854 const char *id, int index, bool shared,
855 bool optional, bool acquired)
857 struct reset_control **ptr, *rstc;
859 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
862 return ERR_PTR(-ENOMEM);
864 rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
865 if (IS_ERR_OR_NULL(rstc)) {
871 devres_add(dev, ptr);
875 EXPORT_SYMBOL_GPL(__devm_reset_control_get);
878 * __device_reset - find reset controller associated with the device
880 * @dev: device to be reset by the controller
881 * @optional: whether it is optional to reset the device
883 * Convenience wrapper for __reset_control_get() and reset_control_reset().
884 * This is useful for the common case of devices with single, dedicated reset
887 int __device_reset(struct device *dev, bool optional)
889 struct reset_control *rstc;
892 rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
894 return PTR_ERR(rstc);
896 ret = reset_control_reset(rstc);
898 reset_control_put(rstc);
902 EXPORT_SYMBOL_GPL(__device_reset);
905 * APIs to manage an array of reset controls.
909 * of_reset_control_get_count - Count number of resets available with a device
911 * @node: device node that contains 'resets'.
913 * Returns positive reset count on success, or error number on failure and
914 * on count being zero.
916 static int of_reset_control_get_count(struct device_node *node)
923 count = of_count_phandle_with_args(node, "resets", "#reset-cells");
931 * of_reset_control_array_get - Get a list of reset controls using
934 * @np: device node for the device that requests the reset controls array
935 * @shared: whether reset controls are shared or not
936 * @optional: whether it is optional to get the reset controls
937 * @acquired: only one reset control may be acquired for a given controller
940 * Returns pointer to allocated reset_control on success or error on failure
942 struct reset_control *
943 of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
946 struct reset_control_array *resets;
947 struct reset_control *rstc;
950 num = of_reset_control_get_count(np);
952 return optional ? NULL : ERR_PTR(num);
954 resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
956 return ERR_PTR(-ENOMEM);
958 for (i = 0; i < num; i++) {
959 rstc = __of_reset_control_get(np, NULL, i, shared, optional,
963 resets->rstc[i] = rstc;
965 resets->num_rstcs = num;
966 resets->base.array = true;
968 return &resets->base;
971 mutex_lock(&reset_list_mutex);
973 __reset_control_put_internal(resets->rstc[i]);
974 mutex_unlock(&reset_list_mutex);
980 EXPORT_SYMBOL_GPL(of_reset_control_array_get);
983 * devm_reset_control_array_get - Resource managed reset control array get
985 * @dev: device that requests the list of reset controls
986 * @shared: whether reset controls are shared or not
987 * @optional: whether it is optional to get the reset controls
989 * The reset control array APIs are intended for a list of resets
990 * that just have to be asserted or deasserted, without any
991 * requirements on the order.
993 * Returns pointer to allocated reset_control on success or error on failure
995 struct reset_control *
996 devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
998 struct reset_control **ptr, *rstc;
1000 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1003 return ERR_PTR(-ENOMEM);
1005 rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
1006 if (IS_ERR_OR_NULL(rstc)) {
1012 devres_add(dev, ptr);
1016 EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
1018 static int reset_control_get_count_from_lookup(struct device *dev)
1020 const struct reset_control_lookup *lookup;
1027 dev_id = dev_name(dev);
1028 mutex_lock(&reset_lookup_mutex);
1030 list_for_each_entry(lookup, &reset_lookup_list, list) {
1031 if (!strcmp(lookup->dev_id, dev_id))
1035 mutex_unlock(&reset_lookup_mutex);
1044 * reset_control_get_count - Count number of resets available with a device
1046 * @dev: device for which to return the number of resets
1048 * Returns positive reset count on success, or error number on failure and
1049 * on count being zero.
1051 int reset_control_get_count(struct device *dev)
1054 return of_reset_control_get_count(dev->of_node);
1056 return reset_control_get_count_from_lookup(dev);
1058 EXPORT_SYMBOL_GPL(reset_control_get_count);