[deliverable/linux.git] / drivers / reset / core.c

/*
 * Reset Controller framework
 *
 * Copyright 2013 Philipp Zabel, Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */
#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/reset.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>

static DEFINE_MUTEX(reset_list_mutex);
static LIST_HEAD(reset_controller_list);

/**
 * struct reset_control - a reset control
 * @rcdev: a pointer to the reset controller device
 *         this reset control belongs to
 * @list: list entry for the rcdev's reset controller list
 * @id: ID of the reset controller in the reset
 *      controller device
 * @refcnt: Number of gets of this reset_control
 * @shared: Is this a shared (1), or an exclusive (0) reset_control?
 * @deassert_cnt: Number of times this reset line has been deasserted
 */
struct reset_control {
	struct reset_controller_dev *rcdev;
	struct list_head list;
	unsigned int id;
	unsigned int refcnt;
	int shared;
	atomic_t deassert_count;
};

/**
 * of_reset_simple_xlate - translate reset_spec to the reset line number
 * @rcdev: a pointer to the reset controller device
 * @reset_spec: reset line specifier as found in the device tree
 * @flags: a flags pointer to fill in (optional)
 *
 * This simple translation function should be used for reset controllers
 * with 1:1 mapping, where reset lines can be indexed by number without gaps.
 */
static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
			  const struct of_phandle_args *reset_spec)
{
	if (reset_spec->args[0] >= rcdev->nr_resets)
		return -EINVAL;

	return reset_spec->args[0];
}

/**
 * reset_controller_register - register a reset controller device
 * @rcdev: a pointer to the initialized reset controller device
 */
int reset_controller_register(struct reset_controller_dev *rcdev)
{
	if (!rcdev->of_xlate) {
		rcdev->of_reset_n_cells = 1;
		rcdev->of_xlate = of_reset_simple_xlate;
	}

	INIT_LIST_HEAD(&rcdev->reset_control_head);

	mutex_lock(&reset_list_mutex);
	list_add(&rcdev->list, &reset_controller_list);
	mutex_unlock(&reset_list_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(reset_controller_register);

/**
 * reset_controller_unregister - unregister a reset controller device
 * @rcdev: a pointer to the reset controller device
 */
void reset_controller_unregister(struct reset_controller_dev *rcdev)
{
	mutex_lock(&reset_list_mutex);
	list_del(&rcdev->list);
	mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_controller_unregister);

static void devm_reset_controller_release(struct device *dev, void *res)
{
	reset_controller_unregister(*(struct reset_controller_dev **)res);
}

/**
 * devm_reset_controller_register - resource managed reset_controller_register()
 * @dev: device that is registering this reset controller
 * @rcdev: a pointer to the initialized reset controller device
 *
 * Managed reset_controller_register(). For reset controllers registered by
 * this function, reset_controller_unregister() is automatically called on
 * driver detach. See reset_controller_register() for more information.
 */
int devm_reset_controller_register(struct device *dev,
				   struct reset_controller_dev *rcdev)
{
	struct reset_controller_dev **rcdevp;
	int ret;

	rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
			      GFP_KERNEL);
	if (!rcdevp)
		return -ENOMEM;

	ret = reset_controller_register(rcdev);
	if (!ret) {
		*rcdevp = rcdev;
		devres_add(dev, rcdevp);
	} else {
		devres_free(rcdevp);
	}

	return ret;
}
EXPORT_SYMBOL_GPL(devm_reset_controller_register);

/**
 * reset_control_reset - reset the controlled device
 * @rstc: reset controller
 *
 * Calling this on a shared reset controller is an error.
 */
int reset_control_reset(struct reset_control *rstc)
{
	if (WARN_ON(rstc->shared))
		return -EINVAL;

	if (rstc->rcdev->ops->reset)
		return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);

	return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(reset_control_reset);

/**
 * reset_control_assert - asserts the reset line
 * @rstc: reset controller
 *
 * Calling this on an exclusive reset controller guarantees that the reset
 * will be asserted. When called on a shared reset controller the line may
 * still be deasserted, as long as other users keep it so.
 *
 * For shared reset controls a driver cannot expect the hw's registers and
 * internal state to be reset, but must be prepared for this to happen.
 */
int reset_control_assert(struct reset_control *rstc)
{
	if (!rstc->rcdev->ops->assert)
		return -ENOTSUPP;

	if (rstc->shared) {
		if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
			return -EINVAL;

		if (atomic_dec_return(&rstc->deassert_count) != 0)
			return 0;
	}

	return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_assert);

/**
 * reset_control_deassert - deasserts the reset line
 * @rstc: reset controller
 *
 * After calling this function, the reset is guaranteed to be deasserted.
 */
int reset_control_deassert(struct reset_control *rstc)
{
	if (!rstc->rcdev->ops->deassert)
		return -ENOTSUPP;

	if (rstc->shared) {
		if (atomic_inc_return(&rstc->deassert_count) != 1)
			return 0;
	}

	return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_deassert);

/**
 * reset_control_status - returns a negative errno if not supported, a
 * positive value if the reset line is asserted, or zero if the reset
 * line is not asserted.
 * @rstc: reset controller
 */
int reset_control_status(struct reset_control *rstc)
{
	if (rstc->rcdev->ops->status)
		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);

	return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(reset_control_status);

static struct reset_control *__reset_control_get(
				struct reset_controller_dev *rcdev,
				unsigned int index, int shared)
{
	struct reset_control *rstc;

	lockdep_assert_held(&reset_list_mutex);

	list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
		if (rstc->id == index) {
			if (WARN_ON(!rstc->shared || !shared))
				return ERR_PTR(-EBUSY);

			rstc->refcnt++;
			return rstc;
		}
	}

	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
	if (!rstc)
		return ERR_PTR(-ENOMEM);

	try_module_get(rcdev->owner);

	rstc->rcdev = rcdev;
	list_add(&rstc->list, &rcdev->reset_control_head);
	rstc->id = index;
	rstc->refcnt = 1;
	rstc->shared = shared;

	return rstc;
}

static void __reset_control_put(struct reset_control *rstc)
{
	lockdep_assert_held(&reset_list_mutex);

	if (--rstc->refcnt)
		return;

	module_put(rstc->rcdev->owner);

	list_del(&rstc->list);
	kfree(rstc);
}

struct reset_control *__of_reset_control_get(struct device_node *node,
				     const char *id, int index, int shared)
{
	struct reset_control *rstc;
	struct reset_controller_dev *r, *rcdev;
	struct of_phandle_args args;
	int rstc_id;
	int ret;

	if (!node)
		return ERR_PTR(-EINVAL);

	if (id) {
		index = of_property_match_string(node,
						 "reset-names", id);
		if (index < 0)
			return ERR_PTR(-ENOENT);
	}

	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
					 index, &args);
	if (ret)
		return ERR_PTR(ret);

	mutex_lock(&reset_list_mutex);
	rcdev = NULL;
	list_for_each_entry(r, &reset_controller_list, list) {
		if (args.np == r->of_node) {
			rcdev = r;
			break;
		}
	}
	of_node_put(args.np);

	if (!rcdev) {
		mutex_unlock(&reset_list_mutex);
		return ERR_PTR(-EPROBE_DEFER);
	}

	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
		mutex_unlock(&reset_list_mutex);
		return ERR_PTR(-EINVAL);
	}

	rstc_id = rcdev->of_xlate(rcdev, &args);
	if (rstc_id < 0) {
		mutex_unlock(&reset_list_mutex);
		return ERR_PTR(rstc_id);
	}

	/* reset_list_mutex also protects the rcdev's reset_control list */
	rstc = __reset_control_get(rcdev, rstc_id, shared);

	mutex_unlock(&reset_list_mutex);

	return rstc;
}
EXPORT_SYMBOL_GPL(__of_reset_control_get);

/**
 * reset_control_put - free the reset controller
 * @rstc: reset controller
 */

void reset_control_put(struct reset_control *rstc)
{
	if (IS_ERR(rstc))
		return;

	mutex_lock(&reset_list_mutex);
	__reset_control_put(rstc);
	mutex_unlock(&reset_list_mutex);
}
EXPORT_SYMBOL_GPL(reset_control_put);

static void devm_reset_control_release(struct device *dev, void *res)
{
	reset_control_put(*(struct reset_control **)res);
}

struct reset_control *__devm_reset_control_get(struct device *dev,
				     const char *id, int index, int shared)
{
	struct reset_control **ptr, *rstc;

	ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
			   GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
				      id, index, shared);
	if (!IS_ERR(rstc)) {
		*ptr = rstc;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return rstc;
}
EXPORT_SYMBOL_GPL(__devm_reset_control_get);

/**
 * device_reset - find reset controller associated with the device
 *                and perform reset
 * @dev: device to be reset by the controller
 *
 * Convenience wrapper for reset_control_get() and reset_control_reset().
 * This is useful for the common case of devices with single, dedicated reset
 * lines.
 */
int device_reset(struct device *dev)
{
	struct reset_control *rstc;
	int ret;

	rstc = reset_control_get(dev, NULL);
	if (IS_ERR(rstc))
		return PTR_ERR(rstc);

	ret = reset_control_reset(rstc);

	reset_control_put(rstc);

	return ret;
}
EXPORT_SYMBOL_GPL(device_reset);
Commit	Line	Data
61fc4131 PZ	1	/*
	2	* Reset Controller framework
	3	*
	4	* Copyright 2013 Philipp Zabel, Pengutronix
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*/
0b52297f	11	#include <linux/atomic.h>
61fc4131 PZ	12	#include <linux/device.h>
	13	#include <linux/err.h>
	14	#include <linux/export.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/of.h>
	18	#include <linux/reset.h>
	19	#include <linux/reset-controller.h>
	20	#include <linux/slab.h>
	21
c15ddec2	22	static DEFINE_MUTEX(reset_list_mutex);
61fc4131 PZ	23	static LIST_HEAD(reset_controller_list);
	24
	25	/**
	26	* struct reset_control - a reset control
	27	* @rcdev: a pointer to the reset controller device
	28	* this reset control belongs to
c15ddec2	29	* @list: list entry for the rcdev's reset controller list
61fc4131 PZ	30	* @id: ID of the reset controller in the reset
61fc4131 PZ	31	* controller device
c15ddec2	32	* @refcnt: Number of gets of this reset_control
0b52297f HG	33	* @shared: Is this a shared (1), or an exclusive (0) reset_control?
0b52297f HG	34	* @deassert_cnt: Number of times this reset line has been deasserted
61fc4131 PZ	35	*/
	36	struct reset_control {
	37	struct reset_controller_dev *rcdev;
c15ddec2	38	struct list_head list;
61fc4131	39	unsigned int id;
c15ddec2	40	unsigned int refcnt;
0b52297f HG	41	int shared;
0b52297f HG	42	atomic_t deassert_count;
61fc4131 PZ	43	};
	44
	45	/**
	46	* of_reset_simple_xlate - translate reset_spec to the reset line number
	47	* @rcdev: a pointer to the reset controller device
	48	* @reset_spec: reset line specifier as found in the device tree
	49	* @flags: a flags pointer to fill in (optional)
	50	*
	51	* This simple translation function should be used for reset controllers
	52	* with 1:1 mapping, where reset lines can be indexed by number without gaps.
	53	*/
0c5b2b91	54	static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
61fc4131 PZ	55	const struct of_phandle_args *reset_spec)
61fc4131 PZ	56	{
61fc4131 PZ	57	if (reset_spec->args[0] >= rcdev->nr_resets)
	58	return -EINVAL;
	59
	60	return reset_spec->args[0];
	61	}
61fc4131 PZ	62
	63	/**
	64	* reset_controller_register - register a reset controller device
	65	* @rcdev: a pointer to the initialized reset controller device
	66	*/
	67	int reset_controller_register(struct reset_controller_dev *rcdev)
	68	{
	69	if (!rcdev->of_xlate) {
	70	rcdev->of_reset_n_cells = 1;
	71	rcdev->of_xlate = of_reset_simple_xlate;
	72	}
	73
c15ddec2 HG	74	INIT_LIST_HEAD(&rcdev->reset_control_head);
	75
	76	mutex_lock(&reset_list_mutex);
61fc4131	77	list_add(&rcdev->list, &reset_controller_list);
c15ddec2	78	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	79
	80	return 0;
	81	}
	82	EXPORT_SYMBOL_GPL(reset_controller_register);
	83
	84	/**
	85	* reset_controller_unregister - unregister a reset controller device
	86	* @rcdev: a pointer to the reset controller device
	87	*/
	88	void reset_controller_unregister(struct reset_controller_dev *rcdev)
	89	{
c15ddec2	90	mutex_lock(&reset_list_mutex);
61fc4131	91	list_del(&rcdev->list);
c15ddec2	92	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	93	}
	94	EXPORT_SYMBOL_GPL(reset_controller_unregister);
	95
8d5b5d5c MY	96	static void devm_reset_controller_release(struct device dev, void res)
	97	{
	98	reset_controller_unregister((struct reset_controller_dev *)res);
	99	}
	100
	101	/**
	102	* devm_reset_controller_register - resource managed reset_controller_register()
	103	* @dev: device that is registering this reset controller
	104	* @rcdev: a pointer to the initialized reset controller device
	105	*
	106	* Managed reset_controller_register(). For reset controllers registered by
	107	* this function, reset_controller_unregister() is automatically called on
	108	* driver detach. See reset_controller_register() for more information.
	109	*/
	110	int devm_reset_controller_register(struct device *dev,
	111	struct reset_controller_dev *rcdev)
	112	{
	113	struct reset_controller_dev **rcdevp;
	114	int ret;
	115
	116	rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
	117	GFP_KERNEL);
	118	if (!rcdevp)
	119	return -ENOMEM;
	120
	121	ret = reset_controller_register(rcdev);
	122	if (!ret) {
	123	*rcdevp = rcdev;
	124	devres_add(dev, rcdevp);
	125	} else {
	126	devres_free(rcdevp);
	127	}
	128
	129	return ret;
	130	}
	131	EXPORT_SYMBOL_GPL(devm_reset_controller_register);
	132
61fc4131 PZ	133	/**
	134	* reset_control_reset - reset the controlled device
	135	* @rstc: reset controller
0b52297f HG	136	*
0b52297f HG	137	* Calling this on a shared reset controller is an error.
61fc4131 PZ	138	*/
	139	int reset_control_reset(struct reset_control *rstc)
	140	{
0b52297f HG	141	if (WARN_ON(rstc->shared))
	142	return -EINVAL;
	143
61fc4131 PZ	144	if (rstc->rcdev->ops->reset)
	145	return rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
	146
39b4da71	147	return -ENOTSUPP;
61fc4131 PZ	148	}
	149	EXPORT_SYMBOL_GPL(reset_control_reset);
	150
	151	/**
	152	* reset_control_assert - asserts the reset line
	153	* @rstc: reset controller
0b52297f HG	154	*
	155	* Calling this on an exclusive reset controller guarantees that the reset
	156	* will be asserted. When called on a shared reset controller the line may
	157	* still be deasserted, as long as other users keep it so.
	158	*
	159	* For shared reset controls a driver cannot expect the hw's registers and
	160	* internal state to be reset, but must be prepared for this to happen.
61fc4131 PZ	161	*/
	162	int reset_control_assert(struct reset_control *rstc)
	163	{
0b52297f HG	164	if (!rstc->rcdev->ops->assert)
0b52297f HG	165	return -ENOTSUPP;
61fc4131	166
0b52297f HG	167	if (rstc->shared) {
	168	if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
	169	return -EINVAL;
	170
	171	if (atomic_dec_return(&rstc->deassert_count) != 0)
	172	return 0;
	173	}
	174
	175	return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
61fc4131 PZ	176	}
	177	EXPORT_SYMBOL_GPL(reset_control_assert);
	178
	179	/**
	180	* reset_control_deassert - deasserts the reset line
	181	* @rstc: reset controller
0b52297f HG	182	*
0b52297f HG	183	* After calling this function, the reset is guaranteed to be deasserted.
61fc4131 PZ	184	*/
	185	int reset_control_deassert(struct reset_control *rstc)
	186	{
0b52297f HG	187	if (!rstc->rcdev->ops->deassert)
0b52297f HG	188	return -ENOTSUPP;
61fc4131	189
0b52297f HG	190	if (rstc->shared) {
	191	if (atomic_inc_return(&rstc->deassert_count) != 1)
	192	return 0;
	193	}
	194
	195	return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
61fc4131 PZ	196	}
	197	EXPORT_SYMBOL_GPL(reset_control_deassert);
	198
729de41b DN	199	/**
	200	* reset_control_status - returns a negative errno if not supported, a
	201	* positive value if the reset line is asserted, or zero if the reset
	202	* line is not asserted.
	203	* @rstc: reset controller
	204	*/
	205	int reset_control_status(struct reset_control *rstc)
	206	{
	207	if (rstc->rcdev->ops->status)
	208	return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
	209
39b4da71	210	return -ENOTSUPP;
729de41b DN	211	}
	212	EXPORT_SYMBOL_GPL(reset_control_status);
	213
c15ddec2 HG	214	static struct reset_control *__reset_control_get(
c15ddec2 HG	215	struct reset_controller_dev *rcdev,
0b52297f	216	unsigned int index, int shared)
c15ddec2 HG	217	{
	218	struct reset_control *rstc;
	219
	220	lockdep_assert_held(&reset_list_mutex);
	221
	222	list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
	223	if (rstc->id == index) {
0b52297f HG	224	if (WARN_ON(!rstc->shared \|\| !shared))
	225	return ERR_PTR(-EBUSY);
	226
c15ddec2 HG	227	rstc->refcnt++;
	228	return rstc;
	229	}
	230	}
	231
	232	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
	233	if (!rstc)
	234	return ERR_PTR(-ENOMEM);
	235
	236	try_module_get(rcdev->owner);
	237
	238	rstc->rcdev = rcdev;
	239	list_add(&rstc->list, &rcdev->reset_control_head);
	240	rstc->id = index;
	241	rstc->refcnt = 1;
0b52297f	242	rstc->shared = shared;
c15ddec2 HG	243
	244	return rstc;
	245	}
	246
	247	static void __reset_control_put(struct reset_control *rstc)
	248	{
	249	lockdep_assert_held(&reset_list_mutex);
	250
	251	if (--rstc->refcnt)
	252	return;
	253
	254	module_put(rstc->rcdev->owner);
	255
	256	list_del(&rstc->list);
	257	kfree(rstc);
	258	}
	259
6c96f05c	260	struct reset_control __of_reset_control_get(struct device_node node,
0b52297f	261	const char *id, int index, int shared)
61fc4131	262	{
d056c9b8	263	struct reset_control *rstc;
61fc4131 PZ	264	struct reset_controller_dev r, rcdev;
61fc4131 PZ	265	struct of_phandle_args args;
61fc4131 PZ	266	int rstc_id;
	267	int ret;
	268
6c96f05c HG	269	if (!node)
	270	return ERR_PTR(-EINVAL);
	271
	272	if (id) {
	273	index = of_property_match_string(node,
	274	"reset-names", id);
	275	if (index < 0)
	276	return ERR_PTR(-ENOENT);
	277	}
	278
fc0a5921	279	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
61fc4131 PZ	280	index, &args);
	281	if (ret)
	282	return ERR_PTR(ret);
	283
c15ddec2	284	mutex_lock(&reset_list_mutex);
61fc4131 PZ	285	rcdev = NULL;
	286	list_for_each_entry(r, &reset_controller_list, list) {
	287	if (args.np == r->of_node) {
	288	rcdev = r;
	289	break;
	290	}
	291	}
	292	of_node_put(args.np);
	293
	294	if (!rcdev) {
c15ddec2	295	mutex_unlock(&reset_list_mutex);
3d103020	296	return ERR_PTR(-EPROBE_DEFER);
61fc4131 PZ	297	}
61fc4131 PZ	298
e677774f	299	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
c15ddec2	300	mutex_unlock(&reset_list_mutex);
e677774f MR	301	return ERR_PTR(-EINVAL);
	302	}
	303
61fc4131 PZ	304	rstc_id = rcdev->of_xlate(rcdev, &args);
61fc4131 PZ	305	if (rstc_id < 0) {
c15ddec2	306	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	307	return ERR_PTR(rstc_id);
	308	}
	309
c15ddec2	310	/* reset_list_mutex also protects the rcdev's reset_control list */
0b52297f	311	rstc = __reset_control_get(rcdev, rstc_id, shared);
61fc4131	312
c15ddec2	313	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	314
	315	return rstc;
	316	}
6c96f05c	317	EXPORT_SYMBOL_GPL(__of_reset_control_get);
61fc4131 PZ	318
	319	/**
	320	* reset_control_put - free the reset controller
	321	* @rstc: reset controller
	322	*/
	323
	324	void reset_control_put(struct reset_control *rstc)
	325	{
	326	if (IS_ERR(rstc))
	327	return;
	328
c15ddec2 HG	329	mutex_lock(&reset_list_mutex);
	330	__reset_control_put(rstc);
	331	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	332	}
	333	EXPORT_SYMBOL_GPL(reset_control_put);
	334
	335	static void devm_reset_control_release(struct device dev, void res)
	336	{
	337	reset_control_put((struct reset_control *)res);
	338	}
	339
6c96f05c	340	struct reset_control __devm_reset_control_get(struct device dev,
0b52297f	341	const char *id, int index, int shared)
61fc4131 PZ	342	{
	343	struct reset_control *ptr, rstc;
	344
	345	ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
	346	GFP_KERNEL);
	347	if (!ptr)
	348	return ERR_PTR(-ENOMEM);
	349
0b52297f HG	350	rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
0b52297f HG	351	id, index, shared);
61fc4131 PZ	352	if (!IS_ERR(rstc)) {
	353	*ptr = rstc;
	354	devres_add(dev, ptr);
	355	} else {
	356	devres_free(ptr);
	357	}
	358
	359	return rstc;
	360	}
6c96f05c	361	EXPORT_SYMBOL_GPL(__devm_reset_control_get);
61fc4131	362
61fc4131 PZ	363	/**
	364	* device_reset - find reset controller associated with the device
	365	* and perform reset
	366	* @dev: device to be reset by the controller
	367	*
	368	* Convenience wrapper for reset_control_get() and reset_control_reset().
	369	* This is useful for the common case of devices with single, dedicated reset
	370	* lines.
	371	*/
	372	int device_reset(struct device *dev)
	373	{
	374	struct reset_control *rstc;
	375	int ret;
	376
	377	rstc = reset_control_get(dev, NULL);
	378	if (IS_ERR(rstc))
	379	return PTR_ERR(rstc);
	380
	381	ret = reset_control_reset(rstc);
	382
	383	reset_control_put(rstc);
	384
	385	return ret;
	386	}
	387	EXPORT_SYMBOL_GPL(device_reset);