[mirror_ubuntu-artful-kernel.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
 * @triggered_count: Number of times this reset line has been reset. Currently
 *                   only used for shared resets, which means that the value
 *                   will be either 0 or 1.
 */
struct reset_control {
	struct reset_controller_dev *rcdev;
	struct list_head list;
	unsigned int id;
	unsigned int refcnt;
	bool shared;
	atomic_t deassert_count;
	atomic_t triggered_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
 *
 * On a shared reset line the actual reset pulse is only triggered once for the
 * lifetime of the reset_control instance: for all but the first caller this is
 * a no-op.
 * Consumers must not use reset_control_(de)assert on shared reset lines when
 * reset_control_reset has been used.
 *
 * If rstc is NULL it is an optional reset and the function will just
 * return 0.
 */
int reset_control_reset(struct reset_control *rstc)
{
	int ret;

	if (!rstc)
		return 0;

	if (WARN_ON(IS_ERR(rstc)))
		return -EINVAL;

	if (!rstc->rcdev->ops->reset)
		return -ENOTSUPP;

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

		if (atomic_inc_return(&rstc->triggered_count) != 1)
			return 0;
	}

	ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
	if (rstc->shared && ret)
		atomic_dec(&rstc->triggered_count);

	return ret;
}
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.
 * Consumers must not use reset_control_reset on shared reset lines when
 * reset_control_(de)assert has been used.
 * return 0.
 *
 * If rstc is NULL it is an optional reset and the function will just
 * return 0.
 */
int reset_control_assert(struct reset_control *rstc)
{
	if (!rstc)
		return 0;

	if (WARN_ON(IS_ERR(rstc)))
		return -EINVAL;

	if (!rstc->rcdev->ops->assert)
		return -ENOTSUPP;

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

		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.
 * Consumers must not use reset_control_reset on shared reset lines when
 * reset_control_(de)assert has been used.
 * return 0.
 *
 * If rstc is NULL it is an optional reset and the function will just
 * return 0.
 */
int reset_control_deassert(struct reset_control *rstc)
{
	if (!rstc)
		return 0;

	if (WARN_ON(IS_ERR(rstc)))
		return -EINVAL;

	if (!rstc->rcdev->ops->deassert)
		return -ENOTSUPP;

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

		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 or if the desc is NULL (optional reset).
 * @rstc: reset controller
 */
int reset_control_status(struct reset_control *rstc)
{
	if (!rstc)
		return 0;

	if (WARN_ON(IS_ERR(rstc)))
		return -EINVAL;

	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, bool 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, bool shared,
				     bool optional)
{
	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 == -EILSEQ)
			return ERR_PTR(index);
		if (index < 0)
			return optional ? NULL : ERR_PTR(-ENOENT);
	}

	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
					 index, &args);
	if (ret == -EINVAL)
		return ERR_PTR(ret);
	if (ret)
		return optional ? NULL : 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_OR_NULL(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, bool shared,
				     bool optional)
{
	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, optional);
	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
7da33a37 MB	35	* @triggered_count: Number of times this reset line has been reset. Currently
	36	* only used for shared resets, which means that the value
	37	* will be either 0 or 1.
61fc4131 PZ	38	*/
	39	struct reset_control {
	40	struct reset_controller_dev *rcdev;
c15ddec2	41	struct list_head list;
61fc4131	42	unsigned int id;
c15ddec2	43	unsigned int refcnt;
ee48c726	44	bool shared;
0b52297f	45	atomic_t deassert_count;
7da33a37	46	atomic_t triggered_count;
61fc4131 PZ	47	};
	48
	49	/**
	50	* of_reset_simple_xlate - translate reset_spec to the reset line number
	51	* @rcdev: a pointer to the reset controller device
	52	* @reset_spec: reset line specifier as found in the device tree
	53	* @flags: a flags pointer to fill in (optional)
	54	*
	55	* This simple translation function should be used for reset controllers
	56	* with 1:1 mapping, where reset lines can be indexed by number without gaps.
	57	*/
0c5b2b91	58	static int of_reset_simple_xlate(struct reset_controller_dev *rcdev,
61fc4131 PZ	59	const struct of_phandle_args *reset_spec)
61fc4131 PZ	60	{
61fc4131 PZ	61	if (reset_spec->args[0] >= rcdev->nr_resets)
	62	return -EINVAL;
	63
	64	return reset_spec->args[0];
	65	}
61fc4131 PZ	66
	67	/**
	68	* reset_controller_register - register a reset controller device
	69	* @rcdev: a pointer to the initialized reset controller device
	70	*/
	71	int reset_controller_register(struct reset_controller_dev *rcdev)
	72	{
	73	if (!rcdev->of_xlate) {
	74	rcdev->of_reset_n_cells = 1;
	75	rcdev->of_xlate = of_reset_simple_xlate;
	76	}
	77
c15ddec2 HG	78	INIT_LIST_HEAD(&rcdev->reset_control_head);
	79
	80	mutex_lock(&reset_list_mutex);
61fc4131	81	list_add(&rcdev->list, &reset_controller_list);
c15ddec2	82	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	83
	84	return 0;
	85	}
	86	EXPORT_SYMBOL_GPL(reset_controller_register);
	87
	88	/**
	89	* reset_controller_unregister - unregister a reset controller device
	90	* @rcdev: a pointer to the reset controller device
	91	*/
	92	void reset_controller_unregister(struct reset_controller_dev *rcdev)
	93	{
c15ddec2	94	mutex_lock(&reset_list_mutex);
61fc4131	95	list_del(&rcdev->list);
c15ddec2	96	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	97	}
	98	EXPORT_SYMBOL_GPL(reset_controller_unregister);
	99
8d5b5d5c MY	100	static void devm_reset_controller_release(struct device dev, void res)
	101	{
	102	reset_controller_unregister((struct reset_controller_dev *)res);
	103	}
	104
	105	/**
	106	* devm_reset_controller_register - resource managed reset_controller_register()
	107	* @dev: device that is registering this reset controller
	108	* @rcdev: a pointer to the initialized reset controller device
	109	*
	110	* Managed reset_controller_register(). For reset controllers registered by
	111	* this function, reset_controller_unregister() is automatically called on
	112	* driver detach. See reset_controller_register() for more information.
	113	*/
	114	int devm_reset_controller_register(struct device *dev,
	115	struct reset_controller_dev *rcdev)
	116	{
	117	struct reset_controller_dev **rcdevp;
	118	int ret;
	119
	120	rcdevp = devres_alloc(devm_reset_controller_release, sizeof(*rcdevp),
	121	GFP_KERNEL);
	122	if (!rcdevp)
	123	return -ENOMEM;
	124
	125	ret = reset_controller_register(rcdev);
	126	if (!ret) {
	127	*rcdevp = rcdev;
	128	devres_add(dev, rcdevp);
	129	} else {
	130	devres_free(rcdevp);
	131	}
	132
	133	return ret;
	134	}
	135	EXPORT_SYMBOL_GPL(devm_reset_controller_register);
	136
61fc4131 PZ	137	/**
	138	* reset_control_reset - reset the controlled device
	139	* @rstc: reset controller
0b52297f	140	*
7da33a37 MB	141	* On a shared reset line the actual reset pulse is only triggered once for the
	142	* lifetime of the reset_control instance: for all but the first caller this is
	143	* a no-op.
	144	* Consumers must not use reset_control_(de)assert on shared reset lines when
	145	* reset_control_reset has been used.
bb475230 RO	146	*
	147	* If rstc is NULL it is an optional reset and the function will just
	148	* return 0.
61fc4131 PZ	149	*/
	150	int reset_control_reset(struct reset_control *rstc)
	151	{
7da33a37 MB	152	int ret;
7da33a37 MB	153
bb475230 RO	154	if (!rstc)
	155	return 0;
	156
	157	if (WARN_ON(IS_ERR(rstc)))
0b52297f HG	158	return -EINVAL;
0b52297f HG	159
7da33a37 MB	160	if (!rstc->rcdev->ops->reset)
	161	return -ENOTSUPP;
	162
	163	if (rstc->shared) {
	164	if (WARN_ON(atomic_read(&rstc->deassert_count) != 0))
	165	return -EINVAL;
	166
	167	if (atomic_inc_return(&rstc->triggered_count) != 1)
	168	return 0;
	169	}
61fc4131	170
7da33a37	171	ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);
e5a1dade	172	if (rstc->shared && ret)
7da33a37 MB	173	atomic_dec(&rstc->triggered_count);
	174
	175	return ret;
61fc4131 PZ	176	}
	177	EXPORT_SYMBOL_GPL(reset_control_reset);
	178
	179	/**
	180	* reset_control_assert - asserts the reset line
	181	* @rstc: reset controller
0b52297f HG	182	*
	183	* Calling this on an exclusive reset controller guarantees that the reset
	184	* will be asserted. When called on a shared reset controller the line may
	185	* still be deasserted, as long as other users keep it so.
	186	*
	187	* For shared reset controls a driver cannot expect the hw's registers and
	188	* internal state to be reset, but must be prepared for this to happen.
7da33a37 MB	189	* Consumers must not use reset_control_reset on shared reset lines when
7da33a37 MB	190	* reset_control_(de)assert has been used.
bb475230 RO	191	* return 0.
	192	*
	193	* If rstc is NULL it is an optional reset and the function will just
	194	* return 0.
61fc4131 PZ	195	*/
	196	int reset_control_assert(struct reset_control *rstc)
	197	{
bb475230 RO	198	if (!rstc)
	199	return 0;
	200
	201	if (WARN_ON(IS_ERR(rstc)))
a3774e14 PZ	202	return -EINVAL;
a3774e14 PZ	203
0b52297f HG	204	if (!rstc->rcdev->ops->assert)
0b52297f HG	205	return -ENOTSUPP;
61fc4131	206
0b52297f	207	if (rstc->shared) {
7da33a37 MB	208	if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
	209	return -EINVAL;
	210
0b52297f HG	211	if (WARN_ON(atomic_read(&rstc->deassert_count) == 0))
	212	return -EINVAL;
	213
	214	if (atomic_dec_return(&rstc->deassert_count) != 0)
	215	return 0;
	216	}
	217
	218	return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
61fc4131 PZ	219	}
	220	EXPORT_SYMBOL_GPL(reset_control_assert);
	221
	222	/**
	223	* reset_control_deassert - deasserts the reset line
	224	* @rstc: reset controller
0b52297f HG	225	*
0b52297f HG	226	* After calling this function, the reset is guaranteed to be deasserted.
7da33a37 MB	227	* Consumers must not use reset_control_reset on shared reset lines when
7da33a37 MB	228	* reset_control_(de)assert has been used.
bb475230 RO	229	* return 0.
	230	*
	231	* If rstc is NULL it is an optional reset and the function will just
	232	* return 0.
61fc4131 PZ	233	*/
	234	int reset_control_deassert(struct reset_control *rstc)
	235	{
bb475230 RO	236	if (!rstc)
	237	return 0;
	238
	239	if (WARN_ON(IS_ERR(rstc)))
a3774e14 PZ	240	return -EINVAL;
a3774e14 PZ	241
0b52297f HG	242	if (!rstc->rcdev->ops->deassert)
0b52297f HG	243	return -ENOTSUPP;
61fc4131	244
0b52297f	245	if (rstc->shared) {
7da33a37 MB	246	if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
	247	return -EINVAL;
	248
0b52297f HG	249	if (atomic_inc_return(&rstc->deassert_count) != 1)
	250	return 0;
	251	}
	252
	253	return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
61fc4131 PZ	254	}
	255	EXPORT_SYMBOL_GPL(reset_control_deassert);
	256
729de41b DN	257	/**
	258	* reset_control_status - returns a negative errno if not supported, a
	259	* positive value if the reset line is asserted, or zero if the reset
bb475230	260	* line is not asserted or if the desc is NULL (optional reset).
729de41b DN	261	* @rstc: reset controller
	262	*/
	263	int reset_control_status(struct reset_control *rstc)
	264	{
bb475230 RO	265	if (!rstc)
	266	return 0;
	267
	268	if (WARN_ON(IS_ERR(rstc)))
a3774e14 PZ	269	return -EINVAL;
a3774e14 PZ	270
729de41b DN	271	if (rstc->rcdev->ops->status)
	272	return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
	273
39b4da71	274	return -ENOTSUPP;
729de41b DN	275	}
	276	EXPORT_SYMBOL_GPL(reset_control_status);
	277
c15ddec2 HG	278	static struct reset_control *__reset_control_get(
c15ddec2 HG	279	struct reset_controller_dev *rcdev,
ee48c726	280	unsigned int index, bool shared)
c15ddec2 HG	281	{
	282	struct reset_control *rstc;
	283
	284	lockdep_assert_held(&reset_list_mutex);
	285
	286	list_for_each_entry(rstc, &rcdev->reset_control_head, list) {
	287	if (rstc->id == index) {
0b52297f HG	288	if (WARN_ON(!rstc->shared \|\| !shared))
	289	return ERR_PTR(-EBUSY);
	290
c15ddec2 HG	291	rstc->refcnt++;
	292	return rstc;
	293	}
	294	}
	295
	296	rstc = kzalloc(sizeof(*rstc), GFP_KERNEL);
	297	if (!rstc)
	298	return ERR_PTR(-ENOMEM);
	299
	300	try_module_get(rcdev->owner);
	301
	302	rstc->rcdev = rcdev;
	303	list_add(&rstc->list, &rcdev->reset_control_head);
	304	rstc->id = index;
	305	rstc->refcnt = 1;
0b52297f	306	rstc->shared = shared;
c15ddec2 HG	307
	308	return rstc;
	309	}
	310
	311	static void __reset_control_put(struct reset_control *rstc)
	312	{
	313	lockdep_assert_held(&reset_list_mutex);
	314
	315	if (--rstc->refcnt)
	316	return;
	317
	318	module_put(rstc->rcdev->owner);
	319
	320	list_del(&rstc->list);
	321	kfree(rstc);
	322	}
	323
6c96f05c	324	struct reset_control __of_reset_control_get(struct device_node node,
bb475230 RO	325	const char *id, int index, bool shared,
bb475230 RO	326	bool optional)
61fc4131	327	{
d056c9b8	328	struct reset_control *rstc;
61fc4131 PZ	329	struct reset_controller_dev r, rcdev;
61fc4131 PZ	330	struct of_phandle_args args;
61fc4131 PZ	331	int rstc_id;
	332	int ret;
	333
6c96f05c HG	334	if (!node)
	335	return ERR_PTR(-EINVAL);
	336
	337	if (id) {
	338	index = of_property_match_string(node,
	339	"reset-names", id);
bb475230 RO	340	if (index == -EILSEQ)
bb475230 RO	341	return ERR_PTR(index);
6c96f05c	342	if (index < 0)
bb475230	343	return optional ? NULL : ERR_PTR(-ENOENT);
6c96f05c HG	344	}
6c96f05c HG	345
fc0a5921	346	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
61fc4131	347	index, &args);
bb475230	348	if (ret == -EINVAL)
61fc4131	349	return ERR_PTR(ret);
bb475230 RO	350	if (ret)
bb475230 RO	351	return optional ? NULL : ERR_PTR(ret);
61fc4131	352
c15ddec2	353	mutex_lock(&reset_list_mutex);
61fc4131 PZ	354	rcdev = NULL;
	355	list_for_each_entry(r, &reset_controller_list, list) {
	356	if (args.np == r->of_node) {
	357	rcdev = r;
	358	break;
	359	}
	360	}
	361	of_node_put(args.np);
	362
	363	if (!rcdev) {
c15ddec2	364	mutex_unlock(&reset_list_mutex);
3d103020	365	return ERR_PTR(-EPROBE_DEFER);
61fc4131 PZ	366	}
61fc4131 PZ	367
e677774f	368	if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
c15ddec2	369	mutex_unlock(&reset_list_mutex);
e677774f MR	370	return ERR_PTR(-EINVAL);
	371	}
	372
61fc4131 PZ	373	rstc_id = rcdev->of_xlate(rcdev, &args);
61fc4131 PZ	374	if (rstc_id < 0) {
c15ddec2	375	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	376	return ERR_PTR(rstc_id);
	377	}
	378
c15ddec2	379	/* reset_list_mutex also protects the rcdev's reset_control list */
0b52297f	380	rstc = __reset_control_get(rcdev, rstc_id, shared);
61fc4131	381
c15ddec2	382	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	383
	384	return rstc;
	385	}
6c96f05c	386	EXPORT_SYMBOL_GPL(__of_reset_control_get);
61fc4131 PZ	387
	388	/**
	389	* reset_control_put - free the reset controller
	390	* @rstc: reset controller
	391	*/
	392
	393	void reset_control_put(struct reset_control *rstc)
	394	{
4891486f	395	if (IS_ERR_OR_NULL(rstc))
61fc4131 PZ	396	return;
61fc4131 PZ	397
c15ddec2 HG	398	mutex_lock(&reset_list_mutex);
	399	__reset_control_put(rstc);
	400	mutex_unlock(&reset_list_mutex);
61fc4131 PZ	401	}
	402	EXPORT_SYMBOL_GPL(reset_control_put);
	403
	404	static void devm_reset_control_release(struct device dev, void res)
	405	{
	406	reset_control_put((struct reset_control *)res);
	407	}
	408
6c96f05c	409	struct reset_control __devm_reset_control_get(struct device dev,
bb475230 RO	410	const char *id, int index, bool shared,
bb475230 RO	411	bool optional)
61fc4131 PZ	412	{
	413	struct reset_control *ptr, rstc;
	414
	415	ptr = devres_alloc(devm_reset_control_release, sizeof(*ptr),
	416	GFP_KERNEL);
	417	if (!ptr)
	418	return ERR_PTR(-ENOMEM);
	419
0b52297f	420	rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
bb475230	421	id, index, shared, optional);
61fc4131 PZ	422	if (!IS_ERR(rstc)) {
	423	*ptr = rstc;
	424	devres_add(dev, ptr);
	425	} else {
	426	devres_free(ptr);
	427	}
	428
	429	return rstc;
	430	}
6c96f05c	431	EXPORT_SYMBOL_GPL(__devm_reset_control_get);
61fc4131	432
61fc4131 PZ	433	/**
	434	* device_reset - find reset controller associated with the device
	435	* and perform reset
	436	* @dev: device to be reset by the controller
	437	*
	438	* Convenience wrapper for reset_control_get() and reset_control_reset().
	439	* This is useful for the common case of devices with single, dedicated reset
	440	* lines.
	441	*/
	442	int device_reset(struct device *dev)
	443	{
	444	struct reset_control *rstc;
	445	int ret;
	446
	447	rstc = reset_control_get(dev, NULL);
	448	if (IS_ERR(rstc))
	449	return PTR_ERR(rstc);
	450
	451	ret = reset_control_reset(rstc);
	452
	453	reset_control_put(rstc);
	454
	455	return ret;
	456	}
	457	EXPORT_SYMBOL_GPL(device_reset);