drivers/regulator/irq_helpers.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 //
 // Copyright (C) 2021 ROHM Semiconductors
 // regulator IRQ based event notification helpers
 //
 // Logic has been partially adapted from qcom-labibb driver.
 //
 // Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/regulator/driver.h>

 #include "internal.h"

 #define REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS 10000

 struct regulator_irq {
 	struct regulator_irq_data rdata;
 	struct regulator_irq_desc desc;
 	int irq;
 	int retry_cnt;
 	struct delayed_work isr_work;
 };

 /*
  * Should only be called from threaded handler to prevent potential deadlock
  */
 static void rdev_flag_err(struct regulator_dev *rdev, int err)
 {
 	spin_lock(&rdev->err_lock);
 	rdev->cached_err |= err;
 	spin_unlock(&rdev->err_lock);
 }

 static void rdev_clear_err(struct regulator_dev *rdev, int err)
 {
 	spin_lock(&rdev->err_lock);
 	rdev->cached_err &= ~err;
 	spin_unlock(&rdev->err_lock);
 }

 static void regulator_notifier_isr_work(struct work_struct *work)
 {
 	struct regulator_irq *h;
 	struct regulator_irq_desc *d;
 	struct regulator_irq_data *rid;
 	int ret = 0;
 	int tmo, i;
 	int num_rdevs;

 	h = container_of(work, struct regulator_irq,
 			    isr_work.work);
 	d = &h->desc;
 	rid = &h->rdata;
 	num_rdevs = rid->num_states;

 reread:
 	if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
 		if (!d->die)
 			return hw_protection_shutdown("Regulator HW failure? - no IC recovery",
 						      REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
 		ret = d->die(rid);
 		/*
 		 * If the 'last resort' IC recovery failed we will have
 		 * nothing else left to do...
 		 */
 		if (ret)
 			return hw_protection_shutdown("Regulator HW failure. IC recovery failed",
 						      REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);

 		/*
 		 * If h->die() was implemented we assume recovery has been
 		 * attempted (probably regulator was shut down) and we
 		 * just enable IRQ and bail-out.
 		 */
 		goto enable_out;
 	}
 	if (d->renable) {
 		ret = d->renable(rid);

 		if (ret == REGULATOR_FAILED_RETRY) {
 			/* Driver could not get current status */
 			h->retry_cnt++;
 			if (!d->reread_ms)
 				goto reread;

 			tmo = d->reread_ms;
 			goto reschedule;
 		}

 		if (ret) {
 			/*
 			 * IC status reading succeeded. update error info
 			 * just in case the renable changed it.
 			 */
 			for (i = 0; i < num_rdevs; i++) {
 				struct regulator_err_state *stat;
 				struct regulator_dev *rdev;

 				stat = &rid->states[i];
 				rdev = stat->rdev;
 				rdev_clear_err(rdev, (~stat->errors) &
 						      stat->possible_errs);
 			}
 			h->retry_cnt++;
 			/*
 			 * The IC indicated problem is still ON - no point in
 			 * re-enabling the IRQ. Retry later.
 			 */
 			tmo = d->irq_off_ms;
 			goto reschedule;
 		}
 	}

 	/*
 	 * Either IC reported problem cleared or no status checker was provided.
 	 * If problems are gone - good. If not - then the IRQ will fire again
 	 * and we'll have a new nice loop. In any case we should clear error
 	 * flags here and re-enable IRQs.
 	 */
 	for (i = 0; i < num_rdevs; i++) {
 		struct regulator_err_state *stat;
 		struct regulator_dev *rdev;

 		stat = &rid->states[i];
 		rdev = stat->rdev;
 		rdev_clear_err(rdev, stat->possible_errs);
 	}

 	/*
 	 * Things have been seemingly successful => zero retry-counter.
 	 */
 	h->retry_cnt = 0;

 enable_out:
 	enable_irq(h->irq);

 	return;

 reschedule:
 	if (!d->high_prio)
 		mod_delayed_work(system_wq, &h->isr_work,
 				 msecs_to_jiffies(tmo));
 	else
 		mod_delayed_work(system_highpri_wq, &h->isr_work,
 				 msecs_to_jiffies(tmo));
 }

 static irqreturn_t regulator_notifier_isr(int irq, void *data)
 {
 	struct regulator_irq *h = data;
 	struct regulator_irq_desc *d;
 	struct regulator_irq_data *rid;
 	unsigned long rdev_map = 0;
 	int num_rdevs;
 	int ret, i;

 	d = &h->desc;
 	rid = &h->rdata;
 	num_rdevs = rid->num_states;

 	if (d->fatal_cnt)
 		h->retry_cnt++;

 	/*
 	 * we spare a few cycles by not clearing statuses prior to this call.
 	 * The IC driver must initialize the status buffers for rdevs
 	 * which it indicates having active events via rdev_map.
 	 *
 	 * Maybe we should just to be on a safer side(?)
 	 */
 	ret = d->map_event(irq, rid, &rdev_map);

 	/*
 	 * If status reading fails (which is unlikely) we don't ack/disable
 	 * IRQ but just increase fail count and retry when IRQ fires again.
 	 * If retry_count exceeds the given safety limit we call IC specific die
 	 * handler which can try disabling regulator(s).
 	 *
 	 * If no die handler is given we will just bug() as a last resort.
 	 *
 	 * We could try disabling all associated rdevs - but we might shoot
 	 * ourselves in the head and leave the problematic regulator enabled. So
 	 * if IC has no die-handler populated we just assume the regulator
 	 * can't be disabled.
 	 */
 	if (unlikely(ret == REGULATOR_FAILED_RETRY))
 		goto fail_out;

 	h->retry_cnt = 0;
 	/*
 	 * Let's not disable IRQ if there were no status bits for us. We'd
 	 * better leave spurious IRQ handling to genirq
 	 */
 	if (ret || !rdev_map)
 		return IRQ_NONE;

 	/*
 	 * Some events are bogus if the regulator is disabled. Skip such events
 	 * if all relevant regulators are disabled
 	 */
 	if (d->skip_off) {
 		for_each_set_bit(i, &rdev_map, num_rdevs) {
 			struct regulator_dev *rdev;
 			const struct regulator_ops *ops;

 			rdev = rid->states[i].rdev;
 			ops = rdev->desc->ops;

 			/*
 			 * If any of the flagged regulators is enabled we do
 			 * handle this
 			 */
 			if (ops->is_enabled(rdev))
 				break;
 		}
 		if (i == num_rdevs)
 			return IRQ_NONE;
 	}

 	/* Disable IRQ if HW keeps line asserted */
 	if (d->irq_off_ms)
 		disable_irq_nosync(irq);

 	/*
 	 * IRQ seems to be for us. Let's fire correct notifiers / store error
 	 * flags
 	 */
 	for_each_set_bit(i, &rdev_map, num_rdevs) {
 		struct regulator_err_state *stat;
 		struct regulator_dev *rdev;

 		stat = &rid->states[i];
 		rdev = stat->rdev;

 		rdev_dbg(rdev, "Sending regulator notification EVT 0x%lx\n",
 			 stat->notifs);

 		regulator_notifier_call_chain(rdev, stat->notifs, NULL);
 		rdev_flag_err(rdev, stat->errors);
 	}

 	if (d->irq_off_ms) {
 		if (!d->high_prio)
 			schedule_delayed_work(&h->isr_work,
 					      msecs_to_jiffies(d->irq_off_ms));
 		else
 			mod_delayed_work(system_highpri_wq,
 					 &h->isr_work,
 					 msecs_to_jiffies(d->irq_off_ms));
 	}

 	return IRQ_HANDLED;

 fail_out:
 	if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
 		/* If we have no recovery, just try shut down straight away */
 		if (!d->die) {
 			hw_protection_shutdown("Regulator failure. Retry count exceeded",
 					       REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
 		} else {
 			ret = d->die(rid);
 			/* If die() failed shut down as a last attempt to save the HW */
 			if (ret)
 				hw_protection_shutdown("Regulator failure. Recovery failed",
 						       REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
 		}
 	}

 	return IRQ_NONE;
 }

 static int init_rdev_state(struct device *dev, struct regulator_irq *h,
 			   struct regulator_dev **rdev, int common_err,
 			   int *rdev_err, int rdev_amount)
 {
 	int i;

 	h->rdata.states = devm_kzalloc(dev, sizeof(*h->rdata.states) *
 				       rdev_amount, GFP_KERNEL);
 	if (!h->rdata.states)
 		return -ENOMEM;

 	h->rdata.num_states = rdev_amount;
 	h->rdata.data = h->desc.data;

 	for (i = 0; i < rdev_amount; i++) {
 		h->rdata.states[i].possible_errs = common_err;
 		if (rdev_err)
 			h->rdata.states[i].possible_errs |= *rdev_err++;
 		h->rdata.states[i].rdev = *rdev++;
 	}

 	return 0;
 }

 static void init_rdev_errors(struct regulator_irq *h)
 {
 	int i;

 	for (i = 0; i < h->rdata.num_states; i++)
 		if (h->rdata.states[i].possible_errs)
 			h->rdata.states[i].rdev->use_cached_err = true;
 }

 /**
  * regulator_irq_helper - register IRQ based regulator event/error notifier
  *
  * @dev:		device providing the IRQs
  * @d:			IRQ helper descriptor.
  * @irq:		IRQ used to inform events/errors to be notified.
  * @irq_flags:		Extra IRQ flags to be OR'ed with the default
  *			IRQF_ONESHOT when requesting the (threaded) irq.
  * @common_errs:	Errors which can be flagged by this IRQ for all rdevs.
  *			When IRQ is re-enabled these errors will be cleared
  *			from all associated regulators
  * @per_rdev_errs:	Optional error flag array describing errors specific
  *			for only some of the regulators. These errors will be
  *			or'ed with common errors. If this is given the array
  *			should contain rdev_amount flags. Can be set to NULL
  *			if there is no regulator specific error flags for this
  *			IRQ.
  * @rdev:		Array of pointers to regulators associated with this
  *			IRQ.
  * @rdev_amount:	Amount of regulators associated with this IRQ.
  *
  * Return: handle to irq_helper or an ERR_PTR() encoded error code.
  */
 void *regulator_irq_helper(struct device *dev,
 			   const struct regulator_irq_desc *d, int irq,
 			   int irq_flags, int common_errs, int *per_rdev_errs,
 			   struct regulator_dev **rdev, int rdev_amount)
 {
 	struct regulator_irq *h;
 	int ret;

 	if (!rdev_amount || !d || !d->map_event || !d->name)
 		return ERR_PTR(-EINVAL);

 	h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL);
 	if (!h)
 		return ERR_PTR(-ENOMEM);

 	h->irq = irq;
 	h->desc = *d;

 	ret = init_rdev_state(dev, h, rdev, common_errs, per_rdev_errs,
 			      rdev_amount);
 	if (ret)
 		return ERR_PTR(ret);

 	init_rdev_errors(h);

 	if (h->desc.irq_off_ms)
 		INIT_DELAYED_WORK(&h->isr_work, regulator_notifier_isr_work);

 	ret = request_threaded_irq(h->irq, NULL, regulator_notifier_isr,
 				   IRQF_ONESHOT | irq_flags, h->desc.name, h);
 	if (ret) {
 		dev_err(dev, "Failed to request IRQ %d\n", irq);

 		return ERR_PTR(ret);
 	}

 	return h;
 }
 EXPORT_SYMBOL_GPL(regulator_irq_helper);

 /**
  * regulator_irq_helper_cancel - drop IRQ based regulator event/error notifier
  *
  * @handle:		Pointer to handle returned by a successful call to
  *			regulator_irq_helper(). Will be NULLed upon return.
  *
  * The associated IRQ is released and work is cancelled when the function
  * returns.
  */
 void regulator_irq_helper_cancel(void **handle)
 {
 	if (handle && *handle) {
 		struct regulator_irq *h = *handle;

 		free_irq(h->irq, h);
 		if (h->desc.irq_off_ms)
 			cancel_delayed_work_sync(&h->isr_work);

 		h = NULL;
 	}
 }
 EXPORT_SYMBOL_GPL(regulator_irq_helper_cancel);
	// SPDX-License-Identifier: GPL-2.0
	//
	// Copyright (C) 2021 ROHM Semiconductors
	// regulator IRQ based event notification helpers
	//
	// Logic has been partially adapted from qcom-labibb driver.
	//
	// Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/interrupt.h>
	#include <linux/kernel.h>
	#include <linux/reboot.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <linux/regulator/driver.h>

	#include "internal.h"

	#define REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS 10000

	struct regulator_irq {
	struct regulator_irq_data rdata;
	struct regulator_irq_desc desc;
	int irq;
	int retry_cnt;
	struct delayed_work isr_work;
	};

	/*
	* Should only be called from threaded handler to prevent potential deadlock
	*/
	static void rdev_flag_err(struct regulator_dev *rdev, int err)
	{
	spin_lock(&rdev->err_lock);
	rdev->cached_err \|= err;
	spin_unlock(&rdev->err_lock);
	}

	static void rdev_clear_err(struct regulator_dev *rdev, int err)
	{
	spin_lock(&rdev->err_lock);
	rdev->cached_err &= ~err;
	spin_unlock(&rdev->err_lock);
	}

	static void regulator_notifier_isr_work(struct work_struct *work)
	{
	struct regulator_irq *h;
	struct regulator_irq_desc *d;
	struct regulator_irq_data *rid;
	int ret = 0;
	int tmo, i;
	int num_rdevs;

	h = container_of(work, struct regulator_irq,
	isr_work.work);
	d = &h->desc;
	rid = &h->rdata;
	num_rdevs = rid->num_states;

	reread:
	if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
	if (!d->die)
	return hw_protection_shutdown("Regulator HW failure? - no IC recovery",
	REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
	ret = d->die(rid);
	/*
	* If the 'last resort' IC recovery failed we will have
	* nothing else left to do...
	*/
	if (ret)
	return hw_protection_shutdown("Regulator HW failure. IC recovery failed",
	REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);

	/*
	* If h->die() was implemented we assume recovery has been
	* attempted (probably regulator was shut down) and we
	* just enable IRQ and bail-out.
	*/
	goto enable_out;
	}
	if (d->renable) {
	ret = d->renable(rid);

	if (ret == REGULATOR_FAILED_RETRY) {
	/* Driver could not get current status */
	h->retry_cnt++;
	if (!d->reread_ms)
	goto reread;

	tmo = d->reread_ms;
	goto reschedule;
	}

	if (ret) {
	/*
	* IC status reading succeeded. update error info
	* just in case the renable changed it.
	*/
	for (i = 0; i < num_rdevs; i++) {
	struct regulator_err_state *stat;
	struct regulator_dev *rdev;

	stat = &rid->states[i];
	rdev = stat->rdev;
	rdev_clear_err(rdev, (~stat->errors) &
	stat->possible_errs);
	}
	h->retry_cnt++;
	/*
	* The IC indicated problem is still ON - no point in
	* re-enabling the IRQ. Retry later.
	*/
	tmo = d->irq_off_ms;
	goto reschedule;
	}
	}

	/*
	* Either IC reported problem cleared or no status checker was provided.
	* If problems are gone - good. If not - then the IRQ will fire again
	* and we'll have a new nice loop. In any case we should clear error
	* flags here and re-enable IRQs.
	*/
	for (i = 0; i < num_rdevs; i++) {
	struct regulator_err_state *stat;
	struct regulator_dev *rdev;

	stat = &rid->states[i];
	rdev = stat->rdev;
	rdev_clear_err(rdev, stat->possible_errs);
	}

	/*
	* Things have been seemingly successful => zero retry-counter.
	*/
	h->retry_cnt = 0;

	enable_out:
	enable_irq(h->irq);

	return;

	reschedule:
	if (!d->high_prio)
	mod_delayed_work(system_wq, &h->isr_work,
	msecs_to_jiffies(tmo));
	else
	mod_delayed_work(system_highpri_wq, &h->isr_work,
	msecs_to_jiffies(tmo));
	}

	static irqreturn_t regulator_notifier_isr(int irq, void *data)
	{
	struct regulator_irq *h = data;
	struct regulator_irq_desc *d;
	struct regulator_irq_data *rid;
	unsigned long rdev_map = 0;
	int num_rdevs;
	int ret, i;

	d = &h->desc;
	rid = &h->rdata;
	num_rdevs = rid->num_states;

	if (d->fatal_cnt)
	h->retry_cnt++;

	/*
	* we spare a few cycles by not clearing statuses prior to this call.
	* The IC driver must initialize the status buffers for rdevs
	* which it indicates having active events via rdev_map.
	*
	* Maybe we should just to be on a safer side(?)
	*/
	ret = d->map_event(irq, rid, &rdev_map);

	/*
	* If status reading fails (which is unlikely) we don't ack/disable
	* IRQ but just increase fail count and retry when IRQ fires again.
	* If retry_count exceeds the given safety limit we call IC specific die
	* handler which can try disabling regulator(s).
	*
	* If no die handler is given we will just bug() as a last resort.
	*
	* We could try disabling all associated rdevs - but we might shoot
	* ourselves in the head and leave the problematic regulator enabled. So
	* if IC has no die-handler populated we just assume the regulator
	* can't be disabled.
	*/
	if (unlikely(ret == REGULATOR_FAILED_RETRY))
	goto fail_out;

	h->retry_cnt = 0;
	/*
	* Let's not disable IRQ if there were no status bits for us. We'd
	* better leave spurious IRQ handling to genirq
	*/
	if (ret \|\| !rdev_map)
	return IRQ_NONE;

	/*
	* Some events are bogus if the regulator is disabled. Skip such events
	* if all relevant regulators are disabled
	*/
	if (d->skip_off) {
	for_each_set_bit(i, &rdev_map, num_rdevs) {
	struct regulator_dev *rdev;
	const struct regulator_ops *ops;

	rdev = rid->states[i].rdev;
	ops = rdev->desc->ops;

	/*
	* If any of the flagged regulators is enabled we do
	* handle this
	*/
	if (ops->is_enabled(rdev))
	break;
	}
	if (i == num_rdevs)
	return IRQ_NONE;
	}

	/* Disable IRQ if HW keeps line asserted */
	if (d->irq_off_ms)
	disable_irq_nosync(irq);

	/*
	* IRQ seems to be for us. Let's fire correct notifiers / store error
	* flags
	*/
	for_each_set_bit(i, &rdev_map, num_rdevs) {
	struct regulator_err_state *stat;
	struct regulator_dev *rdev;

	stat = &rid->states[i];
	rdev = stat->rdev;

	rdev_dbg(rdev, "Sending regulator notification EVT 0x%lx\n",
	stat->notifs);

	regulator_notifier_call_chain(rdev, stat->notifs, NULL);
	rdev_flag_err(rdev, stat->errors);
	}

	if (d->irq_off_ms) {
	if (!d->high_prio)
	schedule_delayed_work(&h->isr_work,
	msecs_to_jiffies(d->irq_off_ms));
	else
	mod_delayed_work(system_highpri_wq,
	&h->isr_work,
	msecs_to_jiffies(d->irq_off_ms));
	}

	return IRQ_HANDLED;

	fail_out:
	if (d->fatal_cnt && h->retry_cnt > d->fatal_cnt) {
	/* If we have no recovery, just try shut down straight away */
	if (!d->die) {
	hw_protection_shutdown("Regulator failure. Retry count exceeded",
	REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
	} else {
	ret = d->die(rid);
	/* If die() failed shut down as a last attempt to save the HW */
	if (ret)
	hw_protection_shutdown("Regulator failure. Recovery failed",
	REGULATOR_FORCED_SAFETY_SHUTDOWN_WAIT_MS);
	}
	}

	return IRQ_NONE;
	}

	static int init_rdev_state(struct device dev, struct regulator_irq h,
	struct regulator_dev **rdev, int common_err,
	int *rdev_err, int rdev_amount)
	{
	int i;

	h->rdata.states = devm_kzalloc(dev, sizeof(h->rdata.states)
	rdev_amount, GFP_KERNEL);
	if (!h->rdata.states)
	return -ENOMEM;

	h->rdata.num_states = rdev_amount;
	h->rdata.data = h->desc.data;

	for (i = 0; i < rdev_amount; i++) {
	h->rdata.states[i].possible_errs = common_err;
	if (rdev_err)
	h->rdata.states[i].possible_errs \|= *rdev_err++;
	h->rdata.states[i].rdev = *rdev++;
	}

	return 0;
	}

	static void init_rdev_errors(struct regulator_irq *h)
	{
	int i;

	for (i = 0; i < h->rdata.num_states; i++)
	if (h->rdata.states[i].possible_errs)
	h->rdata.states[i].rdev->use_cached_err = true;
	}

	/**
	* regulator_irq_helper - register IRQ based regulator event/error notifier
	*
	* @dev: device providing the IRQs
	* @d: IRQ helper descriptor.
	* @irq: IRQ used to inform events/errors to be notified.
	* @irq_flags: Extra IRQ flags to be OR'ed with the default
	* IRQF_ONESHOT when requesting the (threaded) irq.
	* @common_errs: Errors which can be flagged by this IRQ for all rdevs.
	* When IRQ is re-enabled these errors will be cleared
	* from all associated regulators
	* @per_rdev_errs: Optional error flag array describing errors specific
	* for only some of the regulators. These errors will be
	* or'ed with common errors. If this is given the array
	* should contain rdev_amount flags. Can be set to NULL
	* if there is no regulator specific error flags for this
	* IRQ.
	* @rdev: Array of pointers to regulators associated with this
	* IRQ.
	* @rdev_amount: Amount of regulators associated with this IRQ.
	*
	* Return: handle to irq_helper or an ERR_PTR() encoded error code.
	*/
	void regulator_irq_helper(struct device dev,
	const struct regulator_irq_desc *d, int irq,
	int irq_flags, int common_errs, int *per_rdev_errs,
	struct regulator_dev **rdev, int rdev_amount)
	{
	struct regulator_irq *h;
	int ret;

	if (!rdev_amount \|\| !d \|\| !d->map_event \|\| !d->name)
	return ERR_PTR(-EINVAL);

	h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL);
	if (!h)
	return ERR_PTR(-ENOMEM);

	h->irq = irq;
	h->desc = *d;

	ret = init_rdev_state(dev, h, rdev, common_errs, per_rdev_errs,
	rdev_amount);
	if (ret)
	return ERR_PTR(ret);

	init_rdev_errors(h);

	if (h->desc.irq_off_ms)
	INIT_DELAYED_WORK(&h->isr_work, regulator_notifier_isr_work);

	ret = request_threaded_irq(h->irq, NULL, regulator_notifier_isr,
	IRQF_ONESHOT \| irq_flags, h->desc.name, h);
	if (ret) {
	dev_err(dev, "Failed to request IRQ %d\n", irq);

	return ERR_PTR(ret);
	}

	return h;
	}
	EXPORT_SYMBOL_GPL(regulator_irq_helper);

	/**
	* regulator_irq_helper_cancel - drop IRQ based regulator event/error notifier
	*
	* @handle: Pointer to handle returned by a successful call to
	* regulator_irq_helper(). Will be NULLed upon return.
	*
	* The associated IRQ is released and work is cancelled when the function
	* returns.
	*/
	void regulator_irq_helper_cancel(void **handle)
	{
	if (handle && *handle) {
	struct regulator_irq h = handle;

	free_irq(h->irq, h);
	if (h->desc.irq_off_ms)
	cancel_delayed_work_sync(&h->isr_work);

	h = NULL;
	}
	}
	EXPORT_SYMBOL_GPL(regulator_irq_helper_cancel);