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/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>
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>
25 static DEFINE_MUTEX(reset_list_mutex);
26 static LIST_HEAD(reset_controller_list);
28 static DEFINE_MUTEX(reset_lookup_mutex);
29 static LIST_HEAD(reset_lookup_list);
31 /* Protects reset_gpio_lookup_list */
32 static DEFINE_MUTEX(reset_gpio_lookup_mutex);
33 static LIST_HEAD(reset_gpio_lookup_list);
34 static DEFINE_IDA(reset_gpio_ida);
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
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.
52 struct reset_control {
53 struct reset_controller_dev *rcdev;
54 struct list_head list;
60 atomic_t deassert_count;
61 atomic_t triggered_count;
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
70 struct reset_control_array {
71 struct reset_control base;
72 unsigned int num_rstcs;
73 struct reset_control *rstc[] __counted_by(num_rstcs);
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
81 struct reset_gpio_lookup {
82 struct of_phandle_args of_args;
83 struct list_head list;
86 static const char *rcdev_name(struct reset_controller_dev *rcdev)
89 return dev_name(rcdev->dev);
92 return rcdev->of_node->full_name;
95 return rcdev->of_args->np->full_name;
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
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
110 static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
111 const struct of_phandle_args *reset_spec)
113 if (reset_spec->args[0] >= rcdev->nr_resets)
116 return reset_spec->args[0];
120 * reset_controller_register - register a reset controller device
121 * @rcdev: a pointer to the initialized reset controller device
123 int reset_controller_register(struct reset_controller_dev *rcdev)
125 if (rcdev->of_node && rcdev->of_args)
128 if (!rcdev->of_xlate) {
129 rcdev->of_reset_n_cells = 1;
130 rcdev->of_xlate = of_reset_simple_xlate;
133 INIT_LIST_HEAD(&rcdev->reset_control_head);
135 mutex_lock(&reset_list_mutex);
136 list_add(&rcdev->list, &reset_controller_list);
137 mutex_unlock(&reset_list_mutex);
141 EXPORT_SYMBOL_GPL(reset_controller_register);
144 * reset_controller_unregister - unregister a reset controller device
145 * @rcdev: a pointer to the reset controller device
147 void reset_controller_unregister(struct reset_controller_dev *rcdev)
149 mutex_lock(&reset_list_mutex);
150 list_del(&rcdev->list);
151 mutex_unlock(&reset_list_mutex);
153 EXPORT_SYMBOL_GPL(reset_controller_unregister);
155 static void devm_reset_controller_release(struct device *dev, void *res)
157 reset_controller_unregister(*(struct reset_controller_dev **)res);
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
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.
169 int devm_reset_controller_register(struct device *dev,
170 struct reset_controller_dev *rcdev)
172 struct reset_controller_dev **rcdevp;
175 rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
180 ret = reset_controller_register(rcdev);
187 devres_add(dev, rcdevp);
191 EXPORT_SYMBOL_GPL(devm_reset_controller_register);
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
198 void reset_controller_add_lookup(struct reset_control_lookup *lookup,
199 unsigned int num_entries)
201 struct reset_control_lookup *entry;
204 mutex_lock(&reset_lookup_mutex);
205 for (i = 0; i < num_entries; i++) {
208 if (!entry->dev_id || !entry->provider) {
209 pr_warn("%s(): reset lookup entry badly specified, skipping\n",
214 list_add_tail(&entry->list, &reset_lookup_list);
216 mutex_unlock(&reset_lookup_mutex);
218 EXPORT_SYMBOL_GPL(reset_controller_add_lookup);
220 static inline struct reset_control_array *
221 rstc_to_array(struct reset_control *rstc) {
222 return container_of(rstc, struct reset_control_array, base);
225 static int reset_control_array_reset(struct reset_control_array *resets)
229 for (i = 0; i < resets->num_rstcs; i++) {
230 ret = reset_control_reset(resets->rstc[i]);
238 static int reset_control_array_rearm(struct reset_control_array *resets)
240 struct reset_control *rstc;
243 for (i = 0; i < resets->num_rstcs; i++) {
244 rstc = resets->rstc[i];
249 if (WARN_ON(IS_ERR(rstc)))
253 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
261 for (i = 0; i < resets->num_rstcs; i++) {
262 rstc = resets->rstc[i];
264 if (rstc && rstc->shared)
265 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
271 static int reset_control_array_assert(struct reset_control_array *resets)
275 for (i = 0; i < resets->num_rstcs; i++) {
276 ret = reset_control_assert(resets->rstc[i]);
285 reset_control_deassert(resets->rstc[i]);
289 static int reset_control_array_deassert(struct reset_control_array *resets)
293 for (i = 0; i < resets->num_rstcs; i++) {
294 ret = reset_control_deassert(resets->rstc[i]);
303 reset_control_assert(resets->rstc[i]);
307 static int reset_control_array_acquire(struct reset_control_array *resets)
312 for (i = 0; i < resets->num_rstcs; i++) {
313 err = reset_control_acquire(resets->rstc[i]);
322 reset_control_release(resets->rstc[i]);
327 static void reset_control_array_release(struct reset_control_array *resets)
331 for (i = 0; i < resets->num_rstcs; i++)
332 reset_control_release(resets->rstc[i]);
335 static inline bool reset_control_is_array(struct reset_control *rstc)
341 * reset_control_reset - reset the controlled device
342 * @rstc: reset controller
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
347 * Consumers must not use reset_control_(de)assert on shared reset lines when
348 * reset_control_reset has been used.
350 * If rstc is NULL it is an optional reset and the function will just
353 int reset_control_reset(struct reset_control *rstc)
360 if (WARN_ON(IS_ERR(rstc)))
363 if (reset_control_is_array(rstc))
364 return reset_control_array_reset(rstc_to_array(rstc));
366 if (!rstc->rcdev->ops->reset)
370 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
373 if (atomic_inc_return(&rstc->triggered_count) != 1)
380 ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
381 if (rstc->shared && ret)
382 atomic_dec(&rstc->triggered_count);
386 EXPORT_SYMBOL_GPL(reset_control_reset);
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
393 * Issue a reset on all provided reset controls, in order.
395 * See also: reset_control_reset()
397 int reset_control_bulk_reset(int num_rstcs,
398 struct reset_control_bulk_data *rstcs)
402 for (i = 0; i < num_rstcs; i++) {
403 ret = reset_control_reset(rstcs[i].rstc);
410 EXPORT_SYMBOL_GPL(reset_control_bulk_reset);
413 * reset_control_rearm - allow shared reset line to be re-triggered"
414 * @rstc: reset controller
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.
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.
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.
425 * If rstc is NULL the function will just return 0.
427 int reset_control_rearm(struct reset_control *rstc)
432 if (WARN_ON(IS_ERR(rstc)))
435 if (reset_control_is_array(rstc))
436 return reset_control_array_rearm(rstc_to_array(rstc));
439 if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
442 WARN_ON(atomic_dec_return(&rstc->triggered_count) < 0);
450 EXPORT_SYMBOL_GPL(reset_control_rearm);
453 * reset_control_assert - asserts the reset line
454 * @rstc: reset controller
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.
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.
465 * If rstc is NULL it is an optional reset and the function will just
468 int reset_control_assert(struct reset_control *rstc)
473 if (WARN_ON(IS_ERR(rstc)))
476 if (reset_control_is_array(rstc))
477 return reset_control_array_assert(rstc_to_array(rstc));
480 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
483 if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
486 if (atomic_dec_return(&rstc->deassert_count) != 0)
490 * Shared reset controls allow the reset line to be in any state
491 * after this call, so doing nothing is a valid option.
493 if (!rstc->rcdev->ops->assert)
497 * If the reset controller does not implement .assert(), there
498 * is no way to guarantee that the reset line is asserted after
501 if (!rstc->rcdev->ops->assert)
504 if (!rstc->acquired) {
505 WARN(1, "reset %s (ID: %u) is not acquired\n",
506 rcdev_name(rstc->rcdev), rstc->id);
511 return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
513 EXPORT_SYMBOL_GPL(reset_control_assert);
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
520 * Assert the reset lines for all provided reset controls, in order.
521 * If an assertion fails, already asserted resets are deasserted again.
523 * See also: reset_control_assert()
525 int reset_control_bulk_assert(int num_rstcs,
526 struct reset_control_bulk_data *rstcs)
530 for (i = 0; i < num_rstcs; i++) {
531 ret = reset_control_assert(rstcs[i].rstc);
540 reset_control_deassert(rstcs[i].rstc);
543 EXPORT_SYMBOL_GPL(reset_control_bulk_assert);
546 * reset_control_deassert - deasserts the reset line
547 * @rstc: reset controller
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.
553 * If rstc is NULL it is an optional reset and the function will just
556 int reset_control_deassert(struct reset_control *rstc)
561 if (WARN_ON(IS_ERR(rstc)))
564 if (reset_control_is_array(rstc))
565 return reset_control_array_deassert(rstc_to_array(rstc));
568 if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
571 if (atomic_inc_return(&rstc->deassert_count) != 1)
574 if (!rstc->acquired) {
575 WARN(1, "reset %s (ID: %u) is not acquired\n",
576 rcdev_name(rstc->rcdev), rstc->id);
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
588 if (!rstc->rcdev->ops->deassert)
591 return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
593 EXPORT_SYMBOL_GPL(reset_control_deassert);
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
600 * Deassert the reset lines for all provided reset controls, in reverse order.
601 * If a deassertion fails, already deasserted resets are asserted again.
603 * See also: reset_control_deassert()
605 int reset_control_bulk_deassert(int num_rstcs,
606 struct reset_control_bulk_data *rstcs)
610 for (i = num_rstcs - 1; i >= 0; i--) {
611 ret = reset_control_deassert(rstcs[i].rstc);
619 while (i < num_rstcs)
620 reset_control_assert(rstcs[i++].rstc);
623 EXPORT_SYMBOL_GPL(reset_control_bulk_deassert);
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
631 int reset_control_status(struct reset_control *rstc)
636 if (WARN_ON(IS_ERR(rstc)) || reset_control_is_array(rstc))
639 if (rstc->rcdev->ops->status)
640 return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
644 EXPORT_SYMBOL_GPL(reset_control_status);
647 * reset_control_acquire() - acquires a reset control for exclusive use
648 * @rstc: reset control
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.
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.
664 * See also: reset_control_release()
666 int reset_control_acquire(struct reset_control *rstc)
668 struct reset_control *rc;
673 if (WARN_ON(IS_ERR(rstc)))
676 if (reset_control_is_array(rstc))
677 return reset_control_array_acquire(rstc_to_array(rstc));
679 mutex_lock(&reset_list_mutex);
681 if (rstc->acquired) {
682 mutex_unlock(&reset_list_mutex);
686 list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {
687 if (rstc != rc && rstc->id == rc->id) {
689 mutex_unlock(&reset_list_mutex);
695 rstc->acquired = true;
697 mutex_unlock(&reset_list_mutex);
700 EXPORT_SYMBOL_GPL(reset_control_acquire);
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
707 * This is used to explicitly acquire reset controls requested with
708 * reset_control_bulk_get_exclusive_release() for temporary exclusive use.
710 * See also: reset_control_acquire(), reset_control_bulk_release()
712 int reset_control_bulk_acquire(int num_rstcs,
713 struct reset_control_bulk_data *rstcs)
717 for (i = 0; i < num_rstcs; i++) {
718 ret = reset_control_acquire(rstcs[i].rstc);
727 reset_control_release(rstcs[i].rstc);
730 EXPORT_SYMBOL_GPL(reset_control_bulk_acquire);
733 * reset_control_release() - releases exclusive access to a reset control
734 * @rstc: reset control
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.
740 * See also: reset_control_acquire()
742 void reset_control_release(struct reset_control *rstc)
744 if (!rstc || WARN_ON(IS_ERR(rstc)))
747 if (reset_control_is_array(rstc))
748 reset_control_array_release(rstc_to_array(rstc));
750 rstc->acquired = false;
752 EXPORT_SYMBOL_GPL(reset_control_release);
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
759 * Releases exclusive access right to reset controls previously obtained by a
760 * call to reset_control_bulk_acquire().
762 * See also: reset_control_release(), reset_control_bulk_acquire()
764 void reset_control_bulk_release(int num_rstcs,
765 struct reset_control_bulk_data *rstcs)
769 for (i = 0; i < num_rstcs; i++)
770 reset_control_release(rstcs[i].rstc);
772 EXPORT_SYMBOL_GPL(reset_control_bulk_release);
774 static struct reset_control *
775 __reset_control_get_internal(struct reset_controller_dev *rcdev,
776 unsigned int index, bool shared, bool acquired)
778 struct reset_control *rstc;
780 lockdep_assert_held(&reset_list_mutex);
782 list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
783 if (rstc->id == index) {
785 * Allow creating a secondary exclusive reset_control
786 * that is initially not acquired for an already
787 * controlled reset line.
789 if (!rstc->shared && !shared && !acquired)
792 if (WARN_ON(!rstc->shared || !shared))
793 return ERR_PTR(-EBUSY);
795 kref_get(&rstc->refcnt);
800 rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
802 return ERR_PTR(-ENOMEM);
804 if (!try_module_get(rcdev->owner)) {
806 return ERR_PTR(-ENODEV);
810 list_add(&rstc->list, &rcdev->reset_control_head);
812 kref_init(&rstc->refcnt);
813 rstc->acquired = acquired;
814 rstc->shared = shared;
819 static void __reset_control_release(struct kref *kref)
821 struct reset_control *rstc = container_of(kref, struct reset_control,
824 lockdep_assert_held(&reset_list_mutex);
826 module_put(rstc->rcdev->owner);
828 list_del(&rstc->list);
832 static void __reset_control_put_internal(struct reset_control *rstc)
834 lockdep_assert_held(&reset_list_mutex);
836 if (IS_ERR_OR_NULL(rstc))
839 kref_put(&rstc->refcnt, __reset_control_release);
842 static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
844 unsigned int of_flags)
846 const struct fwnode_handle *fwnode = of_fwnode_handle(np);
847 unsigned int lookup_flags;
848 const char *label_tmp;
851 * Later we map GPIO flags between OF and Linux, however not all
852 * constants from include/dt-bindings/gpio/gpio.h and
853 * include/linux/gpio/machine.h match each other.
855 if (of_flags > GPIO_ACTIVE_LOW) {
856 pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",
861 struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
863 return -EPROBE_DEFER;
865 label_tmp = gpio_device_get_label(gdev);
869 char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL);
873 /* Size: one lookup entry plus sentinel */
874 struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2),
879 lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);
883 lookup_flags = GPIO_PERSISTENT;
884 lookup_flags |= of_flags & GPIO_ACTIVE_LOW;
885 lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",
888 /* Not freed on success, because it is persisent subsystem data. */
889 gpiod_add_lookup_table(no_free_ptr(lookup));
895 * @args: phandle to the GPIO provider with all the args like GPIO number
897 static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
899 struct reset_gpio_lookup *rgpio_dev;
900 struct platform_device *pdev;
904 * Currently only #gpio-cells=2 is supported with the meaning of:
905 * args[0]: GPIO number
906 * args[1]: GPIO flags
907 * TODO: Handle other cases.
909 if (args->args_count != 2)
913 * Registering reset-gpio device might cause immediate
914 * bind, resulting in its probe() registering new reset controller thus
915 * taking reset_list_mutex lock via reset_controller_register().
917 lockdep_assert_not_held(&reset_list_mutex);
919 mutex_lock(&reset_gpio_lookup_mutex);
921 list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) {
922 if (args->np == rgpio_dev->of_args.np) {
923 if (of_phandle_args_equal(args, &rgpio_dev->of_args))
924 goto out; /* Already on the list, done */
928 id = ida_alloc(&reset_gpio_ida, GFP_KERNEL);
934 /* Not freed on success, because it is persisent subsystem data. */
935 rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL);
941 ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0],
946 rgpio_dev->of_args = *args;
948 * We keep the device_node reference, but of_args.np is put at the end
949 * of __of_reset_control_get(), so get it one more time.
950 * Hold reference as long as rgpio_dev memory is valid.
952 of_node_get(rgpio_dev->of_args.np);
953 pdev = platform_device_register_data(NULL, "reset-gpio", id,
955 sizeof(rgpio_dev->of_args));
956 ret = PTR_ERR_OR_ZERO(pdev);
960 list_add(&rgpio_dev->list, &reset_gpio_lookup_list);
963 mutex_unlock(&reset_gpio_lookup_mutex);
968 of_node_put(rgpio_dev->of_args.np);
972 ida_free(&reset_gpio_ida, id);
974 mutex_unlock(&reset_gpio_lookup_mutex);
979 static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
982 struct reset_controller_dev *rcdev;
984 lockdep_assert_held(&reset_list_mutex);
986 list_for_each_entry(rcdev, &reset_controller_list, list) {
988 if (rcdev->of_args && of_phandle_args_equal(args,
992 if (args->np == rcdev->of_node)
1000 struct reset_control *
1001 __of_reset_control_get(struct device_node *node, const char *id, int index,
1002 bool shared, bool optional, bool acquired)
1004 bool gpio_fallback = false;
1005 struct reset_control *rstc;
1006 struct reset_controller_dev *rcdev;
1007 struct of_phandle_args args;
1012 return ERR_PTR(-EINVAL);
1015 index = of_property_match_string(node,
1017 if (index == -EILSEQ)
1018 return ERR_PTR(index);
1020 return optional ? NULL : ERR_PTR(-ENOENT);
1023 ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
1026 return ERR_PTR(ret);
1028 if (!IS_ENABLED(CONFIG_RESET_GPIO))
1029 return optional ? NULL : ERR_PTR(ret);
1032 * There can be only one reset-gpio for regular devices, so
1033 * don't bother with the "reset-gpios" phandle index.
1035 ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",
1038 return optional ? NULL : ERR_PTR(ret);
1040 gpio_fallback = true;
1042 ret = __reset_add_reset_gpio_device(&args);
1044 rstc = ERR_PTR(ret);
1049 mutex_lock(&reset_list_mutex);
1050 rcdev = __reset_find_rcdev(&args, gpio_fallback);
1052 rstc = ERR_PTR(-EPROBE_DEFER);
1056 if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
1057 rstc = ERR_PTR(-EINVAL);
1061 rstc_id = rcdev->of_xlate(rcdev, &args);
1063 rstc = ERR_PTR(rstc_id);
1067 /* reset_list_mutex also protects the rcdev's reset_control list */
1068 rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
1071 mutex_unlock(&reset_list_mutex);
1073 of_node_put(args.np);
1077 EXPORT_SYMBOL_GPL(__of_reset_control_get);
1079 static struct reset_controller_dev *
1080 __reset_controller_by_name(const char *name)
1082 struct reset_controller_dev *rcdev;
1084 lockdep_assert_held(&reset_list_mutex);
1086 list_for_each_entry(rcdev, &reset_controller_list, list) {
1090 if (!strcmp(name, dev_name(rcdev->dev)))
1097 static struct reset_control *
1098 __reset_control_get_from_lookup(struct device *dev, const char *con_id,
1099 bool shared, bool optional, bool acquired)
1101 const struct reset_control_lookup *lookup;
1102 struct reset_controller_dev *rcdev;
1103 const char *dev_id = dev_name(dev);
1104 struct reset_control *rstc = NULL;
1106 mutex_lock(&reset_lookup_mutex);
1108 list_for_each_entry(lookup, &reset_lookup_list, list) {
1109 if (strcmp(lookup->dev_id, dev_id))
1112 if ((!con_id && !lookup->con_id) ||
1113 ((con_id && lookup->con_id) &&
1114 !strcmp(con_id, lookup->con_id))) {
1115 mutex_lock(&reset_list_mutex);
1116 rcdev = __reset_controller_by_name(lookup->provider);
1118 mutex_unlock(&reset_list_mutex);
1119 mutex_unlock(&reset_lookup_mutex);
1120 /* Reset provider may not be ready yet. */
1121 return ERR_PTR(-EPROBE_DEFER);
1124 rstc = __reset_control_get_internal(rcdev,
1127 mutex_unlock(&reset_list_mutex);
1132 mutex_unlock(&reset_lookup_mutex);
1135 return optional ? NULL : ERR_PTR(-ENOENT);
1140 struct reset_control *__reset_control_get(struct device *dev, const char *id,
1141 int index, bool shared, bool optional,
1144 if (WARN_ON(shared && acquired))
1145 return ERR_PTR(-EINVAL);
1148 return __of_reset_control_get(dev->of_node, id, index, shared,
1149 optional, acquired);
1151 return __reset_control_get_from_lookup(dev, id, shared, optional,
1154 EXPORT_SYMBOL_GPL(__reset_control_get);
1156 int __reset_control_bulk_get(struct device *dev, int num_rstcs,
1157 struct reset_control_bulk_data *rstcs,
1158 bool shared, bool optional, bool acquired)
1162 for (i = 0; i < num_rstcs; i++) {
1163 rstcs[i].rstc = __reset_control_get(dev, rstcs[i].id, 0,
1164 shared, optional, acquired);
1165 if (IS_ERR(rstcs[i].rstc)) {
1166 ret = PTR_ERR(rstcs[i].rstc);
1174 mutex_lock(&reset_list_mutex);
1176 __reset_control_put_internal(rstcs[i].rstc);
1177 mutex_unlock(&reset_list_mutex);
1180 EXPORT_SYMBOL_GPL(__reset_control_bulk_get);
1182 static void reset_control_array_put(struct reset_control_array *resets)
1186 mutex_lock(&reset_list_mutex);
1187 for (i = 0; i < resets->num_rstcs; i++)
1188 __reset_control_put_internal(resets->rstc[i]);
1189 mutex_unlock(&reset_list_mutex);
1194 * reset_control_put - free the reset controller
1195 * @rstc: reset controller
1197 void reset_control_put(struct reset_control *rstc)
1199 if (IS_ERR_OR_NULL(rstc))
1202 if (reset_control_is_array(rstc)) {
1203 reset_control_array_put(rstc_to_array(rstc));
1207 mutex_lock(&reset_list_mutex);
1208 __reset_control_put_internal(rstc);
1209 mutex_unlock(&reset_list_mutex);
1211 EXPORT_SYMBOL_GPL(reset_control_put);
1214 * reset_control_bulk_put - free the reset controllers
1215 * @num_rstcs: number of entries in rstcs array
1216 * @rstcs: array of struct reset_control_bulk_data with reset controls set
1218 void reset_control_bulk_put(int num_rstcs, struct reset_control_bulk_data *rstcs)
1220 mutex_lock(&reset_list_mutex);
1222 __reset_control_put_internal(rstcs[num_rstcs].rstc);
1223 mutex_unlock(&reset_list_mutex);
1225 EXPORT_SYMBOL_GPL(reset_control_bulk_put);
1227 static void devm_reset_control_release(struct device *dev, void *res)
1229 reset_control_put(*(struct reset_control **)res);
1232 struct reset_control *
1233 __devm_reset_control_get(struct device *dev, const char *id, int index,
1234 bool shared, bool optional, bool acquired)
1236 struct reset_control **ptr, *rstc;
1238 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1241 return ERR_PTR(-ENOMEM);
1243 rstc = __reset_control_get(dev, id, index, shared, optional, acquired);
1244 if (IS_ERR_OR_NULL(rstc)) {
1250 devres_add(dev, ptr);
1254 EXPORT_SYMBOL_GPL(__devm_reset_control_get);
1256 struct reset_control_bulk_devres {
1258 struct reset_control_bulk_data *rstcs;
1261 static void devm_reset_control_bulk_release(struct device *dev, void *res)
1263 struct reset_control_bulk_devres *devres = res;
1265 reset_control_bulk_put(devres->num_rstcs, devres->rstcs);
1268 int __devm_reset_control_bulk_get(struct device *dev, int num_rstcs,
1269 struct reset_control_bulk_data *rstcs,
1270 bool shared, bool optional, bool acquired)
1272 struct reset_control_bulk_devres *ptr;
1275 ptr = devres_alloc(devm_reset_control_bulk_release, sizeof(*ptr),
1280 ret = __reset_control_bulk_get(dev, num_rstcs, rstcs, shared, optional, acquired);
1286 ptr->num_rstcs = num_rstcs;
1288 devres_add(dev, ptr);
1292 EXPORT_SYMBOL_GPL(__devm_reset_control_bulk_get);
1295 * __device_reset - find reset controller associated with the device
1297 * @dev: device to be reset by the controller
1298 * @optional: whether it is optional to reset the device
1300 * Convenience wrapper for __reset_control_get() and reset_control_reset().
1301 * This is useful for the common case of devices with single, dedicated reset
1302 * lines. _RST firmware method will be called for devices with ACPI.
1304 int __device_reset(struct device *dev, bool optional)
1306 struct reset_control *rstc;
1310 acpi_handle handle = ACPI_HANDLE(dev);
1313 if (!acpi_has_method(handle, "_RST"))
1314 return optional ? 0 : -ENOENT;
1315 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL,
1321 rstc = __reset_control_get(dev, NULL, 0, 0, optional, true);
1323 return PTR_ERR(rstc);
1325 ret = reset_control_reset(rstc);
1327 reset_control_put(rstc);
1331 EXPORT_SYMBOL_GPL(__device_reset);
1334 * APIs to manage an array of reset controls.
1338 * of_reset_control_get_count - Count number of resets available with a device
1340 * @node: device node that contains 'resets'.
1342 * Returns positive reset count on success, or error number on failure and
1343 * on count being zero.
1345 static int of_reset_control_get_count(struct device_node *node)
1352 count = of_count_phandle_with_args(node, "resets", "#reset-cells");
1360 * of_reset_control_array_get - Get a list of reset controls using
1363 * @np: device node for the device that requests the reset controls array
1364 * @shared: whether reset controls are shared or not
1365 * @optional: whether it is optional to get the reset controls
1366 * @acquired: only one reset control may be acquired for a given controller
1369 * Returns pointer to allocated reset_control on success or error on failure
1371 struct reset_control *
1372 of_reset_control_array_get(struct device_node *np, bool shared, bool optional,
1375 struct reset_control_array *resets;
1376 struct reset_control *rstc;
1379 num = of_reset_control_get_count(np);
1381 return optional ? NULL : ERR_PTR(num);
1383 resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL);
1385 return ERR_PTR(-ENOMEM);
1386 resets->num_rstcs = num;
1388 for (i = 0; i < num; i++) {
1389 rstc = __of_reset_control_get(np, NULL, i, shared, optional,
1393 resets->rstc[i] = rstc;
1395 resets->base.array = true;
1397 return &resets->base;
1400 mutex_lock(&reset_list_mutex);
1402 __reset_control_put_internal(resets->rstc[i]);
1403 mutex_unlock(&reset_list_mutex);
1409 EXPORT_SYMBOL_GPL(of_reset_control_array_get);
1412 * devm_reset_control_array_get - Resource managed reset control array get
1414 * @dev: device that requests the list of reset controls
1415 * @shared: whether reset controls are shared or not
1416 * @optional: whether it is optional to get the reset controls
1418 * The reset control array APIs are intended for a list of resets
1419 * that just have to be asserted or deasserted, without any
1420 * requirements on the order.
1422 * Returns pointer to allocated reset_control on success or error on failure
1424 struct reset_control *
1425 devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
1427 struct reset_control **ptr, *rstc;
1429 ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
1432 return ERR_PTR(-ENOMEM);
1434 rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
1435 if (IS_ERR_OR_NULL(rstc)) {
1441 devres_add(dev, ptr);
1445 EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
1447 static int reset_control_get_count_from_lookup(struct device *dev)
1449 const struct reset_control_lookup *lookup;
1456 dev_id = dev_name(dev);
1457 mutex_lock(&reset_lookup_mutex);
1459 list_for_each_entry(lookup, &reset_lookup_list, list) {
1460 if (!strcmp(lookup->dev_id, dev_id))
1464 mutex_unlock(&reset_lookup_mutex);
1473 * reset_control_get_count - Count number of resets available with a device
1475 * @dev: device for which to return the number of resets
1477 * Returns positive reset count on success, or error number on failure and
1478 * on count being zero.
1480 int reset_control_get_count(struct device *dev)
1483 return of_reset_control_get_count(dev->of_node);
1485 return reset_control_get_count_from_lookup(dev);
1487 EXPORT_SYMBOL_GPL(reset_control_get_count);