1 // SPDX-License-Identifier: GPL-2.0-or-later
16 #include <linux/reset-controller.h>
26  * struct reset_control - a reset control
54  * struct reset_control_array - an array of reset controls
67 	if (rcdev->dev)  in rcdev_name()
68 		return dev_name(rcdev->dev);  in rcdev_name()
70 	if (rcdev->of_node)  in rcdev_name()
71 		return rcdev->of_node->full_name;  in rcdev_name()
77  * of_reset_simple_xlate - translate reset_spec to the reset line number
89 	if (reset_spec->args[0] >= rcdev->nr_resets)  in of_reset_simple_xlate()
90 		return -EINVAL;  in of_reset_simple_xlate()
92 	return reset_spec->args[0];  in of_reset_simple_xlate()
96  * reset_controller_register - register a reset controller device
101 	if (!rcdev->of_xlate) {  in reset_controller_register()
102 		rcdev->of_reset_n_cells = 1;  in reset_controller_register()
103 		rcdev->of_xlate = of_reset_simple_xlate;  in reset_controller_register()
106 	INIT_LIST_HEAD(&rcdev->reset_control_head);  in reset_controller_register()
109 	list_add(&rcdev->list, &reset_controller_list);  in reset_controller_register()
117  * reset_controller_unregister - unregister a reset controller device
123 	list_del(&rcdev->list);  in reset_controller_unregister()
134  * devm_reset_controller_register - resource managed reset_controller_register()
151 		return -ENOMEM;  in devm_reset_controller_register()
167  * reset_controller_add_lookup - register a set of lookup entries
181 		if (!entry->dev_id || !entry->provider) {  in reset_controller_add_lookup()
187 		list_add_tail(&entry->list, &reset_lookup_list);  in reset_controller_add_lookup()
202 	for (i = 0; i < resets->num_rstcs; i++) {  in reset_control_array_reset()
203 		ret = reset_control_reset(resets->rstc[i]);  in reset_control_array_reset()
215 	for (i = 0; i < resets->num_rstcs; i++) {  in reset_control_array_assert()
216 		ret = reset_control_assert(resets->rstc[i]);  in reset_control_array_assert()
224 	while (i--)  in reset_control_array_assert()
225 		reset_control_deassert(resets->rstc[i]);  in reset_control_array_assert()
233 	for (i = 0; i < resets->num_rstcs; i++) {  in reset_control_array_deassert()
234 		ret = reset_control_deassert(resets->rstc[i]);  in reset_control_array_deassert()
242 	while (i--)  in reset_control_array_deassert()
243 		reset_control_assert(resets->rstc[i]);  in reset_control_array_deassert()
252 	for (i = 0; i < resets->num_rstcs; i++) {  in reset_control_array_acquire()
253 		err = reset_control_acquire(resets->rstc[i]);  in reset_control_array_acquire()
261 	while (i--)  in reset_control_array_acquire()
262 		reset_control_release(resets->rstc[i]);  in reset_control_array_acquire()
271 	for (i = 0; i < resets->num_rstcs; i++)  in reset_control_array_release()
272 		reset_control_release(resets->rstc[i]);  in reset_control_array_release()
277 	return rstc->array;  in reset_control_is_array()
281  * reset_control_reset - reset the controlled device
286  * a no-op.
287  * Consumers must not use reset_control_(de)assert on shared reset lines when
301 		return -EINVAL;  in reset_control_reset()
306 	if (!rstc->rcdev->ops->reset)  in reset_control_reset()
307 		return -ENOTSUPP;  in reset_control_reset()
309 	if (rstc->shared) {  in reset_control_reset()
310 		if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))  in reset_control_reset()
311 			return -EINVAL;  in reset_control_reset()
313 		if (atomic_inc_return(&rstc->triggered_count) != 1)  in reset_control_reset()
316 		if (!rstc->acquired)  in reset_control_reset()
317 			return -EPERM;  in reset_control_reset()
320 	ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);  in reset_control_reset()
321 	if (rstc->shared && ret)  in reset_control_reset()
322 		atomic_dec(&rstc->triggered_count);  in reset_control_reset()
329  * reset_control_assert - asserts the reset line
333  * will be asserted. When called on a shared reset controller the line may
339  * reset_control_(de)assert has been used.
350 		return -EINVAL;  in reset_control_assert()
355 	if (rstc->shared) {  in reset_control_assert()
356 		if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))  in reset_control_assert()
357 			return -EINVAL;  in reset_control_assert()
359 		if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))  in reset_control_assert()
360 			return -EINVAL;  in reset_control_assert()
362 		if (atomic_dec_return(&rstc->deassert_count) != 0)  in reset_control_assert()
369 		if (!rstc->rcdev->ops->assert)  in reset_control_assert()
374 		 * is no way to guarantee that the reset line is asserted after  in reset_control_assert()
377 		if (!rstc->rcdev->ops->assert)  in reset_control_assert()
378 			return -ENOTSUPP;  in reset_control_assert()
380 		if (!rstc->acquired) {  in reset_control_assert()
382 			     rcdev_name(rstc->rcdev), rstc->id);  in reset_control_assert()
383 			return -EPERM;  in reset_control_assert()
387 	return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);  in reset_control_assert()
392  * reset_control_deassert - deasserts the reset line
397  * reset_control_(de)assert has been used.
408 		return -EINVAL;  in reset_control_deassert()
413 	if (rstc->shared) {  in reset_control_deassert()
414 		if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))  in reset_control_deassert()
415 			return -EINVAL;  in reset_control_deassert()
417 		if (atomic_inc_return(&rstc->deassert_count) != 1)  in reset_control_deassert()
420 		if (!rstc->acquired) {  in reset_control_deassert()
422 			     rcdev_name(rstc->rcdev), rstc->id);  in reset_control_deassert()
423 			return -EPERM;  in reset_control_deassert()
429 	 * that it handles self-deasserting reset lines via .reset(). In that  in reset_control_deassert()
432 	 * return -ENOTSUPP.  in reset_control_deassert()
434 	if (!rstc->rcdev->ops->deassert)  in reset_control_deassert()
437 	return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);  in reset_control_deassert()
442  * reset_control_status - returns a negative errno if not supported, a
443  * positive value if the reset line is asserted, or zero if the reset
444  * line is not asserted or if the desc is NULL (optional reset).
453 		return -EINVAL;  in reset_control_status()
455 	if (rstc->rcdev->ops->status)  in reset_control_status()
456 		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);  in reset_control_status()
458 	return -ENOTSUPP;  in reset_control_status()
463  * reset_control_acquire() - acquires a reset control for exclusive use
490 		return -EINVAL;  in reset_control_acquire()
497 	if (rstc->acquired) {  in reset_control_acquire()
502 	list_for_each_entry(rc, &rstc->rcdev->reset_control_head, list) {  in reset_control_acquire()
503 		if (rstc != rc && rstc->id == rc->id) {  in reset_control_acquire()
504 			if (rc->acquired) {  in reset_control_acquire()
506 				return -EBUSY;  in reset_control_acquire()
511 	rstc->acquired = true;  in reset_control_acquire()
519  * reset_control_release() - releases exclusive access to a reset control
536 		rstc->acquired = false;  in reset_control_release()
548 	list_for_each_entry(rstc, &rcdev->reset_control_head, list) {  in __reset_control_get_internal()
549 		if (rstc->id == index) {  in __reset_control_get_internal()
555 			if (!rstc->shared && !shared && !acquired)  in __reset_control_get_internal()
558 			if (WARN_ON(!rstc->shared || !shared))  in __reset_control_get_internal()
559 				return ERR_PTR(-EBUSY);  in __reset_control_get_internal()
561 			kref_get(&rstc->refcnt);  in __reset_control_get_internal()
568 		return ERR_PTR(-ENOMEM);  in __reset_control_get_internal()
570 	try_module_get(rcdev->owner);  in __reset_control_get_internal()
572 	rstc->rcdev = rcdev;  in __reset_control_get_internal()
573 	list_add(&rstc->list, &rcdev->reset_control_head);  in __reset_control_get_internal()
574 	rstc->id = index;  in __reset_control_get_internal()
575 	kref_init(&rstc->refcnt);  in __reset_control_get_internal()
576 	rstc->acquired = acquired;  in __reset_control_get_internal()
577 	rstc->shared = shared;  in __reset_control_get_internal()
589 	module_put(rstc->rcdev->owner);  in __reset_control_release()
591 	list_del(&rstc->list);  in __reset_control_release()
599 	kref_put(&rstc->refcnt, __reset_control_release);  in __reset_control_put_internal()
613 		return ERR_PTR(-EINVAL);  in __of_reset_control_get()
617 						 "reset-names", id);  in __of_reset_control_get()
618 		if (index == -EILSEQ)  in __of_reset_control_get()
621 			return optional ? NULL : ERR_PTR(-ENOENT);  in __of_reset_control_get()
624 	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",  in __of_reset_control_get()
626 	if (ret == -EINVAL)  in __of_reset_control_get()
634 		if (args.np == r->of_node) {  in __of_reset_control_get()
641 		rstc = ERR_PTR(-EPROBE_DEFER);  in __of_reset_control_get()
645 	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {  in __of_reset_control_get()
646 		rstc = ERR_PTR(-EINVAL);  in __of_reset_control_get()
650 	rstc_id = rcdev->of_xlate(rcdev, &args);  in __of_reset_control_get()
675 		if (!rcdev->dev)  in __reset_controller_by_name()
678 		if (!strcmp(name, dev_name(rcdev->dev)))  in __reset_controller_by_name()
697 		if (strcmp(lookup->dev_id, dev_id))  in __reset_control_get_from_lookup()
700 		if ((!con_id && !lookup->con_id) ||  in __reset_control_get_from_lookup()
701 		    ((con_id && lookup->con_id) &&  in __reset_control_get_from_lookup()
702 		     !strcmp(con_id, lookup->con_id))) {  in __reset_control_get_from_lookup()
704 			rcdev = __reset_controller_by_name(lookup->provider);  in __reset_control_get_from_lookup()
709 				return ERR_PTR(-EPROBE_DEFER);  in __reset_control_get_from_lookup()
713 							    lookup->index,  in __reset_control_get_from_lookup()
723 		return optional ? NULL : ERR_PTR(-ENOENT);  in __reset_control_get_from_lookup()
733 		return ERR_PTR(-EINVAL);  in __reset_control_get()
735 	if (dev->of_node)  in __reset_control_get()
736 		return __of_reset_control_get(dev->of_node, id, index, shared,  in __reset_control_get()
749 	for (i = 0; i < resets->num_rstcs; i++)  in reset_control_array_put()
750 		__reset_control_put_internal(resets->rstc[i]);  in reset_control_array_put()
756  * reset_control_put - free the reset controller
789 		return ERR_PTR(-ENOMEM);  in __devm_reset_control_get()
805  * device_reset - find reset controller associated with the device
836  * of_reset_control_get_count - Count number of resets available with a device
848 		return -EINVAL;  in of_reset_control_get_count()
850 	count = of_count_phandle_with_args(node, "resets", "#reset-cells");  in of_reset_control_get_count()
852 		count = -ENOENT;  in of_reset_control_get_count()
858  * of_reset_control_array_get - Get a list of reset controls using
883 		return ERR_PTR(-ENOMEM);  in of_reset_control_array_get()
890 		resets->rstc[i] = rstc;  in of_reset_control_array_get()
892 	resets->num_rstcs = num;  in of_reset_control_array_get()
893 	resets->base.array = true;  in of_reset_control_array_get()
895 	return &resets->base;  in of_reset_control_array_get()
899 	while (--i >= 0)  in of_reset_control_array_get()
900 		__reset_control_put_internal(resets->rstc[i]);  in of_reset_control_array_get()
910  * devm_reset_control_array_get - Resource managed reset control array get
917  * that just have to be asserted or deasserted, without any
930 		return ERR_PTR(-ENOMEM);  in devm_reset_control_array_get()
932 	rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);  in devm_reset_control_array_get()
952 		return -EINVAL;  in reset_control_get_count_from_lookup()
958 		if (!strcmp(lookup->dev_id, dev_id))  in reset_control_get_count_from_lookup()
965 		count = -ENOENT;  in reset_control_get_count_from_lookup()
971  * reset_control_get_count - Count number of resets available with a device
980 	if (dev->of_node)  in reset_control_get_count()
981 		return of_reset_control_get_count(dev->of_node);  in reset_control_get_count()