drivers/iio/industrialio-trigger.c - pub/scm/linux/kernel/git/joro/linux - Git at Google

 /* The industrial I/O core, trigger handling functions
  *
  * Copyright (c) 2008 Jonathan Cameron
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */

 #include <linux/kernel.h>
 #include <linux/idr.h>
 #include <linux/err.h>
 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/slab.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/trigger.h>
 #include "iio_core.h"
 #include "iio_core_trigger.h"
 #include <linux/iio/trigger_consumer.h>

 /* RFC - Question of approach
  * Make the common case (single sensor single trigger)
  * simple by starting trigger capture from when first sensors
  * is added.
  *
  * Complex simultaneous start requires use of 'hold' functionality
  * of the trigger. (not implemented)
  *
  * Any other suggestions?
  */

 static DEFINE_IDA(iio_trigger_ida);

 /* Single list of all available triggers */
 static LIST_HEAD(iio_trigger_list);
 static DEFINE_MUTEX(iio_trigger_list_lock);

 /**
  * iio_trigger_read_name() - retrieve useful identifying name
  **/
 static ssize_t iio_trigger_read_name(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
 {
 	struct iio_trigger *trig = to_iio_trigger(dev);
 	return sprintf(buf, "%s\n", trig->name);
 }

 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);

 static struct attribute *iio_trig_dev_attrs[] = {
 	&dev_attr_name.attr,
 	NULL,
 };

 static struct attribute_group iio_trig_attr_group = {
 	.attrs	= iio_trig_dev_attrs,
 };

 static const struct attribute_group *iio_trig_attr_groups[] = {
 	&iio_trig_attr_group,
 	NULL
 };

 int iio_trigger_register(struct iio_trigger *trig_info)
 {
 	int ret;

 	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
 	if (trig_info->id < 0) {
 		ret = trig_info->id;
 		goto error_ret;
 	}
 	/* Set the name used for the sysfs directory etc */
 	dev_set_name(&trig_info->dev, "trigger%ld",
 		     (unsigned long) trig_info->id);

 	ret = device_add(&trig_info->dev);
 	if (ret)
 		goto error_unregister_id;

 	/* Add to list of available triggers held by the IIO core */
 	mutex_lock(&iio_trigger_list_lock);
 	list_add_tail(&trig_info->list, &iio_trigger_list);
 	mutex_unlock(&iio_trigger_list_lock);

 	return 0;

 error_unregister_id:
 	ida_simple_remove(&iio_trigger_ida, trig_info->id);
 error_ret:
 	return ret;
 }
 EXPORT_SYMBOL(iio_trigger_register);

 void iio_trigger_unregister(struct iio_trigger *trig_info)
 {
 	mutex_lock(&iio_trigger_list_lock);
 	list_del(&trig_info->list);
 	mutex_unlock(&iio_trigger_list_lock);

 	ida_simple_remove(&iio_trigger_ida, trig_info->id);
 	/* Possible issue in here */
 	device_unregister(&trig_info->dev);
 }
 EXPORT_SYMBOL(iio_trigger_unregister);

 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 						    size_t len)
 {
 	struct iio_trigger *trig = NULL, *iter;

 	mutex_lock(&iio_trigger_list_lock);
 	list_for_each_entry(iter, &iio_trigger_list, list)
 		if (sysfs_streq(iter->name, name)) {
 			trig = iter;
 			break;
 		}
 	mutex_unlock(&iio_trigger_list_lock);

 	return trig;
 }

 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 {
 	int i;
 	if (!trig->use_count)
 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 			if (trig->subirqs[i].enabled) {
 				trig->use_count++;
 				generic_handle_irq(trig->subirq_base + i);
 			}
 }
 EXPORT_SYMBOL(iio_trigger_poll);

 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 {
 	iio_trigger_poll(private, iio_get_time_ns());
 	return IRQ_HANDLED;
 }
 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);

 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 {
 	int i;
 	if (!trig->use_count)
 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 			if (trig->subirqs[i].enabled) {
 				trig->use_count++;
 				handle_nested_irq(trig->subirq_base + i);
 			}
 }
 EXPORT_SYMBOL(iio_trigger_poll_chained);

 void iio_trigger_notify_done(struct iio_trigger *trig)
 {
 	trig->use_count--;
 	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 		if (trig->ops->try_reenable(trig))
 			/* Missed and interrupt so launch new poll now */
 			iio_trigger_poll(trig, 0);
 }
 EXPORT_SYMBOL(iio_trigger_notify_done);

 /* Trigger Consumer related functions */
 static int iio_trigger_get_irq(struct iio_trigger *trig)
 {
 	int ret;
 	mutex_lock(&trig->pool_lock);
 	ret = bitmap_find_free_region(trig->pool,
 				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 				      ilog2(1));
 	mutex_unlock(&trig->pool_lock);
 	if (ret >= 0)
 		ret += trig->subirq_base;

 	return ret;
 }

 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 {
 	mutex_lock(&trig->pool_lock);
 	clear_bit(irq - trig->subirq_base, trig->pool);
 	mutex_unlock(&trig->pool_lock);
 }

 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
  * may be needed if the pollfuncs do not include the data read for the
  * triggering device.
  * This is not currently handled.  Alternative of not enabling trigger unless
  * the relevant function is in there may be the best option.
  */
 /* Worth protecting against double additions?*/
 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 					struct iio_poll_func *pf)
 {
 	int ret = 0;
 	bool notinuse
 		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);

 	/* Prevent the module being removed whilst attached to a trigger */
 	__module_get(pf->indio_dev->info->driver_module);
 	pf->irq = iio_trigger_get_irq(trig);
 	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 				   pf->type, pf->name,
 				   pf);
 	if (ret < 0) {
 		module_put(pf->indio_dev->info->driver_module);
 		return ret;
 	}

 	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
 		ret = trig->ops->set_trigger_state(trig, true);
 		if (ret < 0)
 			module_put(pf->indio_dev->info->driver_module);
 	}

 	return ret;
 }

 static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
 					 struct iio_poll_func *pf)
 {
 	int ret = 0;
 	bool no_other_users
 		= (bitmap_weight(trig->pool,
 				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 		   == 1);
 	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 		ret = trig->ops->set_trigger_state(trig, false);
 		if (ret)
 			goto error_ret;
 	}
 	iio_trigger_put_irq(trig, pf->irq);
 	free_irq(pf->irq, pf);
 	module_put(pf->indio_dev->info->driver_module);

 error_ret:
 	return ret;
 }

 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	pf->timestamp = iio_get_time_ns();
 	return IRQ_WAKE_THREAD;
 }
 EXPORT_SYMBOL(iio_pollfunc_store_time);

 struct iio_poll_func
 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 		    irqreturn_t (*thread)(int irq, void *p),
 		    int type,
 		    struct iio_dev *indio_dev,
 		    const char *fmt,
 		    ...)
 {
 	va_list vargs;
 	struct iio_poll_func *pf;

 	pf = kmalloc(sizeof *pf, GFP_KERNEL);
 	if (pf == NULL)
 		return NULL;
 	va_start(vargs, fmt);
 	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 	va_end(vargs);
 	if (pf->name == NULL) {
 		kfree(pf);
 		return NULL;
 	}
 	pf->h = h;
 	pf->thread = thread;
 	pf->type = type;
 	pf->indio_dev = indio_dev;

 	return pf;
 }
 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);

 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 {
 	kfree(pf->name);
 	kfree(pf);
 }
 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);

 /**
  * iio_trigger_read_current() - trigger consumer sysfs query which trigger
  *
  * For trigger consumers the current_trigger interface allows the trigger
  * used by the device to be queried.
  **/
 static ssize_t iio_trigger_read_current(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);

 	if (indio_dev->trig)
 		return sprintf(buf, "%s\n", indio_dev->trig->name);
 	return 0;
 }

 /**
  * iio_trigger_write_current() trigger consumer sysfs set current trigger
  *
  * For trigger consumers the current_trigger interface allows the trigger
  * used for this device to be specified at run time based on the triggers
  * name.
  **/
 static ssize_t iio_trigger_write_current(struct device *dev,
 					 struct device_attribute *attr,
 					 const char *buf,
 					 size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_trigger *oldtrig = indio_dev->trig;
 	struct iio_trigger *trig;
 	int ret;

 	mutex_lock(&indio_dev->mlock);
 	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 		mutex_unlock(&indio_dev->mlock);
 		return -EBUSY;
 	}
 	mutex_unlock(&indio_dev->mlock);

 	trig = iio_trigger_find_by_name(buf, len);
 	if (oldtrig == trig)
 		return len;

 	if (trig && indio_dev->info->validate_trigger) {
 		ret = indio_dev->info->validate_trigger(indio_dev, trig);
 		if (ret)
 			return ret;
 	}

 	if (trig && trig->ops && trig->ops->validate_device) {
 		ret = trig->ops->validate_device(trig, indio_dev);
 		if (ret)
 			return ret;
 	}

 	indio_dev->trig = trig;

 	if (oldtrig && indio_dev->trig != oldtrig)
 		iio_trigger_put(oldtrig);
 	if (indio_dev->trig)
 		iio_trigger_get(indio_dev->trig);

 	return len;
 }

 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 		   iio_trigger_read_current,
 		   iio_trigger_write_current);

 static struct attribute *iio_trigger_consumer_attrs[] = {
 	&dev_attr_current_trigger.attr,
 	NULL,
 };

 static const struct attribute_group iio_trigger_consumer_attr_group = {
 	.name = "trigger",
 	.attrs = iio_trigger_consumer_attrs,
 };

 static void iio_trig_release(struct device *device)
 {
 	struct iio_trigger *trig = to_iio_trigger(device);
 	int i;

 	if (trig->subirq_base) {
 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 			irq_modify_status(trig->subirq_base + i,
 					  IRQ_NOAUTOEN,
 					  IRQ_NOREQUEST | IRQ_NOPROBE);
 			irq_set_chip(trig->subirq_base + i,
 				     NULL);
 			irq_set_handler(trig->subirq_base + i,
 					NULL);
 		}

 		irq_free_descs(trig->subirq_base,
 			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 	}
 	kfree(trig->name);
 	kfree(trig);
 }

 static struct device_type iio_trig_type = {
 	.release = iio_trig_release,
 	.groups = iio_trig_attr_groups,
 };

 static void iio_trig_subirqmask(struct irq_data *d)
 {
 	struct irq_chip *chip = irq_data_get_irq_chip(d);
 	struct iio_trigger *trig
 		= container_of(chip,
 			       struct iio_trigger, subirq_chip);
 	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 }

 static void iio_trig_subirqunmask(struct irq_data *d)
 {
 	struct irq_chip *chip = irq_data_get_irq_chip(d);
 	struct iio_trigger *trig
 		= container_of(chip,
 			       struct iio_trigger, subirq_chip);
 	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 }

 struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
 {
 	va_list vargs;
 	struct iio_trigger *trig;
 	trig = kzalloc(sizeof *trig, GFP_KERNEL);
 	if (trig) {
 		int i;
 		trig->dev.type = &iio_trig_type;
 		trig->dev.bus = &iio_bus_type;
 		device_initialize(&trig->dev);

 		mutex_init(&trig->pool_lock);
 		trig->subirq_base
 			= irq_alloc_descs(-1, 0,
 					  CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 					  0);
 		if (trig->subirq_base < 0) {
 			kfree(trig);
 			return NULL;
 		}
 		va_start(vargs, fmt);
 		trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 		va_end(vargs);
 		if (trig->name == NULL) {
 			irq_free_descs(trig->subirq_base,
 				       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 			kfree(trig);
 			return NULL;
 		}
 		trig->subirq_chip.name = trig->name;
 		trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 		trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 			irq_set_chip(trig->subirq_base + i,
 				     &trig->subirq_chip);
 			irq_set_handler(trig->subirq_base + i,
 					&handle_simple_irq);
 			irq_modify_status(trig->subirq_base + i,
 					  IRQ_NOREQUEST | IRQ_NOAUTOEN,
 					  IRQ_NOPROBE);
 		}
 		get_device(&trig->dev);
 	}
 	return trig;
 }
 EXPORT_SYMBOL(iio_trigger_alloc);

 void iio_trigger_free(struct iio_trigger *trig)
 {
 	if (trig)
 		put_device(&trig->dev);
 }
 EXPORT_SYMBOL(iio_trigger_free);

 void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 {
 	indio_dev->groups[indio_dev->groupcounter++] =
 		&iio_trigger_consumer_attr_group;
 }

 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
 {
 	/* Clean up and associated but not attached triggers references */
 	if (indio_dev->trig)
 		iio_trigger_put(indio_dev->trig);
 }

 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
 {
 	return iio_trigger_attach_poll_func(indio_dev->trig,
 					    indio_dev->pollfunc);
 }
 EXPORT_SYMBOL(iio_triggered_buffer_postenable);

 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
 {
 	return iio_trigger_detach_poll_func(indio_dev->trig,
 					     indio_dev->pollfunc);
 }
 EXPORT_SYMBOL(iio_triggered_buffer_predisable);
	/* The industrial I/O core, trigger handling functions
	*
	* Copyright (c) 2008 Jonathan Cameron
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*/

	#include <linux/kernel.h>
	#include <linux/idr.h>
	#include <linux/err.h>
	#include <linux/device.h>
	#include <linux/interrupt.h>
	#include <linux/list.h>
	#include <linux/slab.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/trigger.h>
	#include "iio_core.h"
	#include "iio_core_trigger.h"
	#include <linux/iio/trigger_consumer.h>

	/* RFC - Question of approach
	* Make the common case (single sensor single trigger)
	* simple by starting trigger capture from when first sensors
	* is added.
	*
	* Complex simultaneous start requires use of 'hold' functionality
	* of the trigger. (not implemented)
	*
	* Any other suggestions?
	*/

	static DEFINE_IDA(iio_trigger_ida);

	/* Single list of all available triggers */
	static LIST_HEAD(iio_trigger_list);
	static DEFINE_MUTEX(iio_trigger_list_lock);

	/**
	* iio_trigger_read_name() - retrieve useful identifying name
	**/
	static ssize_t iio_trigger_read_name(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_trigger *trig = to_iio_trigger(dev);
	return sprintf(buf, "%s\n", trig->name);
	}

	static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);

	static struct attribute *iio_trig_dev_attrs[] = {
	&dev_attr_name.attr,
	NULL,
	};

	static struct attribute_group iio_trig_attr_group = {
	.attrs = iio_trig_dev_attrs,
	};

	static const struct attribute_group *iio_trig_attr_groups[] = {
	&iio_trig_attr_group,
	NULL
	};

	int iio_trigger_register(struct iio_trigger *trig_info)
	{
	int ret;

	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
	if (trig_info->id < 0) {
	ret = trig_info->id;
	goto error_ret;
	}
	/* Set the name used for the sysfs directory etc */
	dev_set_name(&trig_info->dev, "trigger%ld",
	(unsigned long) trig_info->id);

	ret = device_add(&trig_info->dev);
	if (ret)
	goto error_unregister_id;

	/* Add to list of available triggers held by the IIO core */
	mutex_lock(&iio_trigger_list_lock);
	list_add_tail(&trig_info->list, &iio_trigger_list);
	mutex_unlock(&iio_trigger_list_lock);

	return 0;

	error_unregister_id:
	ida_simple_remove(&iio_trigger_ida, trig_info->id);
	error_ret:
	return ret;
	}
	EXPORT_SYMBOL(iio_trigger_register);

	void iio_trigger_unregister(struct iio_trigger *trig_info)
	{
	mutex_lock(&iio_trigger_list_lock);
	list_del(&trig_info->list);
	mutex_unlock(&iio_trigger_list_lock);

	ida_simple_remove(&iio_trigger_ida, trig_info->id);
	/* Possible issue in here */
	device_unregister(&trig_info->dev);
	}
	EXPORT_SYMBOL(iio_trigger_unregister);

	static struct iio_trigger iio_trigger_find_by_name(const char name,
	size_t len)
	{
	struct iio_trigger trig = NULL, iter;

	mutex_lock(&iio_trigger_list_lock);
	list_for_each_entry(iter, &iio_trigger_list, list)
	if (sysfs_streq(iter->name, name)) {
	trig = iter;
	break;
	}
	mutex_unlock(&iio_trigger_list_lock);

	return trig;
	}

	void iio_trigger_poll(struct iio_trigger *trig, s64 time)
	{
	int i;
	if (!trig->use_count)
	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
	if (trig->subirqs[i].enabled) {
	trig->use_count++;
	generic_handle_irq(trig->subirq_base + i);
	}
	}
	EXPORT_SYMBOL(iio_trigger_poll);

	irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
	{
	iio_trigger_poll(private, iio_get_time_ns());
	return IRQ_HANDLED;
	}
	EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);

	void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
	{
	int i;
	if (!trig->use_count)
	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
	if (trig->subirqs[i].enabled) {
	trig->use_count++;
	handle_nested_irq(trig->subirq_base + i);
	}
	}
	EXPORT_SYMBOL(iio_trigger_poll_chained);

	void iio_trigger_notify_done(struct iio_trigger *trig)
	{
	trig->use_count--;
	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
	if (trig->ops->try_reenable(trig))
	/* Missed and interrupt so launch new poll now */
	iio_trigger_poll(trig, 0);
	}
	EXPORT_SYMBOL(iio_trigger_notify_done);

	/* Trigger Consumer related functions */
	static int iio_trigger_get_irq(struct iio_trigger *trig)
	{
	int ret;
	mutex_lock(&trig->pool_lock);
	ret = bitmap_find_free_region(trig->pool,
	CONFIG_IIO_CONSUMERS_PER_TRIGGER,
	ilog2(1));
	mutex_unlock(&trig->pool_lock);
	if (ret >= 0)
	ret += trig->subirq_base;

	return ret;
	}

	static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
	{
	mutex_lock(&trig->pool_lock);
	clear_bit(irq - trig->subirq_base, trig->pool);
	mutex_unlock(&trig->pool_lock);
	}

	/* Complexity in here. With certain triggers (datardy) an acknowledgement
	* may be needed if the pollfuncs do not include the data read for the
	* triggering device.
	* This is not currently handled. Alternative of not enabling trigger unless
	* the relevant function is in there may be the best option.
	*/
	/* Worth protecting against double additions?*/
	static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
	struct iio_poll_func *pf)
	{
	int ret = 0;
	bool notinuse
	= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);

	/* Prevent the module being removed whilst attached to a trigger */
	__module_get(pf->indio_dev->info->driver_module);
	pf->irq = iio_trigger_get_irq(trig);
	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
	pf->type, pf->name,
	pf);
	if (ret < 0) {
	module_put(pf->indio_dev->info->driver_module);
	return ret;
	}

	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
	ret = trig->ops->set_trigger_state(trig, true);
	if (ret < 0)
	module_put(pf->indio_dev->info->driver_module);
	}

	return ret;
	}

	static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
	struct iio_poll_func *pf)
	{
	int ret = 0;
	bool no_other_users
	= (bitmap_weight(trig->pool,
	CONFIG_IIO_CONSUMERS_PER_TRIGGER)
	== 1);
	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
	ret = trig->ops->set_trigger_state(trig, false);
	if (ret)
	goto error_ret;
	}
	iio_trigger_put_irq(trig, pf->irq);
	free_irq(pf->irq, pf);
	module_put(pf->indio_dev->info->driver_module);

	error_ret:
	return ret;
	}

	irqreturn_t iio_pollfunc_store_time(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	pf->timestamp = iio_get_time_ns();
	return IRQ_WAKE_THREAD;
	}
	EXPORT_SYMBOL(iio_pollfunc_store_time);

	struct iio_poll_func
	iio_alloc_pollfunc(irqreturn_t (h)(int irq, void *p),
	irqreturn_t (thread)(int irq, void p),
	int type,
	struct iio_dev *indio_dev,
	const char *fmt,
	...)
	{
	va_list vargs;
	struct iio_poll_func *pf;

	pf = kmalloc(sizeof *pf, GFP_KERNEL);
	if (pf == NULL)
	return NULL;
	va_start(vargs, fmt);
	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
	va_end(vargs);
	if (pf->name == NULL) {
	kfree(pf);
	return NULL;
	}
	pf->h = h;
	pf->thread = thread;
	pf->type = type;
	pf->indio_dev = indio_dev;

	return pf;
	}
	EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);

	void iio_dealloc_pollfunc(struct iio_poll_func *pf)
	{
	kfree(pf->name);
	kfree(pf);
	}
	EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);

	/**
	* iio_trigger_read_current() - trigger consumer sysfs query which trigger
	*
	* For trigger consumers the current_trigger interface allows the trigger
	* used by the device to be queried.
	**/
	static ssize_t iio_trigger_read_current(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);

	if (indio_dev->trig)
	return sprintf(buf, "%s\n", indio_dev->trig->name);
	return 0;
	}

	/**
	* iio_trigger_write_current() trigger consumer sysfs set current trigger
	*
	* For trigger consumers the current_trigger interface allows the trigger
	* used for this device to be specified at run time based on the triggers
	* name.
	**/
	static ssize_t iio_trigger_write_current(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct iio_trigger *oldtrig = indio_dev->trig;
	struct iio_trigger *trig;
	int ret;

	mutex_lock(&indio_dev->mlock);
	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
	mutex_unlock(&indio_dev->mlock);
	return -EBUSY;
	}
	mutex_unlock(&indio_dev->mlock);

	trig = iio_trigger_find_by_name(buf, len);
	if (oldtrig == trig)
	return len;

	if (trig && indio_dev->info->validate_trigger) {
	ret = indio_dev->info->validate_trigger(indio_dev, trig);
	if (ret)
	return ret;
	}

	if (trig && trig->ops && trig->ops->validate_device) {
	ret = trig->ops->validate_device(trig, indio_dev);
	if (ret)
	return ret;
	}

	indio_dev->trig = trig;

	if (oldtrig && indio_dev->trig != oldtrig)
	iio_trigger_put(oldtrig);
	if (indio_dev->trig)
	iio_trigger_get(indio_dev->trig);

	return len;
	}

	static DEVICE_ATTR(current_trigger, S_IRUGO \| S_IWUSR,
	iio_trigger_read_current,
	iio_trigger_write_current);

	static struct attribute *iio_trigger_consumer_attrs[] = {
	&dev_attr_current_trigger.attr,
	NULL,
	};

	static const struct attribute_group iio_trigger_consumer_attr_group = {
	.name = "trigger",
	.attrs = iio_trigger_consumer_attrs,
	};

	static void iio_trig_release(struct device *device)
	{
	struct iio_trigger *trig = to_iio_trigger(device);
	int i;

	if (trig->subirq_base) {
	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
	irq_modify_status(trig->subirq_base + i,
	IRQ_NOAUTOEN,
	IRQ_NOREQUEST \| IRQ_NOPROBE);
	irq_set_chip(trig->subirq_base + i,
	NULL);
	irq_set_handler(trig->subirq_base + i,
	NULL);
	}

	irq_free_descs(trig->subirq_base,
	CONFIG_IIO_CONSUMERS_PER_TRIGGER);
	}
	kfree(trig->name);
	kfree(trig);
	}

	static struct device_type iio_trig_type = {
	.release = iio_trig_release,
	.groups = iio_trig_attr_groups,
	};

	static void iio_trig_subirqmask(struct irq_data *d)
	{
	struct irq_chip *chip = irq_data_get_irq_chip(d);
	struct iio_trigger *trig
	= container_of(chip,
	struct iio_trigger, subirq_chip);
	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
	}

	static void iio_trig_subirqunmask(struct irq_data *d)
	{
	struct irq_chip *chip = irq_data_get_irq_chip(d);
	struct iio_trigger *trig
	= container_of(chip,
	struct iio_trigger, subirq_chip);
	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
	}

	struct iio_trigger iio_trigger_alloc(const char fmt, ...)
	{
	va_list vargs;
	struct iio_trigger *trig;
	trig = kzalloc(sizeof *trig, GFP_KERNEL);
	if (trig) {
	int i;
	trig->dev.type = &iio_trig_type;
	trig->dev.bus = &iio_bus_type;
	device_initialize(&trig->dev);

	mutex_init(&trig->pool_lock);
	trig->subirq_base
	= irq_alloc_descs(-1, 0,
	CONFIG_IIO_CONSUMERS_PER_TRIGGER,
	0);
	if (trig->subirq_base < 0) {
	kfree(trig);
	return NULL;
	}
	va_start(vargs, fmt);
	trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
	va_end(vargs);
	if (trig->name == NULL) {
	irq_free_descs(trig->subirq_base,
	CONFIG_IIO_CONSUMERS_PER_TRIGGER);
	kfree(trig);
	return NULL;
	}
	trig->subirq_chip.name = trig->name;
	trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
	trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
	irq_set_chip(trig->subirq_base + i,
	&trig->subirq_chip);
	irq_set_handler(trig->subirq_base + i,
	&handle_simple_irq);
	irq_modify_status(trig->subirq_base + i,
	IRQ_NOREQUEST \| IRQ_NOAUTOEN,
	IRQ_NOPROBE);
	}
	get_device(&trig->dev);
	}
	return trig;
	}
	EXPORT_SYMBOL(iio_trigger_alloc);

	void iio_trigger_free(struct iio_trigger *trig)
	{
	if (trig)
	put_device(&trig->dev);
	}
	EXPORT_SYMBOL(iio_trigger_free);

	void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
	{
	indio_dev->groups[indio_dev->groupcounter++] =
	&iio_trigger_consumer_attr_group;
	}

	void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
	{
	/* Clean up and associated but not attached triggers references */
	if (indio_dev->trig)
	iio_trigger_put(indio_dev->trig);
	}

	int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
	{
	return iio_trigger_attach_poll_func(indio_dev->trig,
	indio_dev->pollfunc);
	}
	EXPORT_SYMBOL(iio_triggered_buffer_postenable);

	int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
	{
	return iio_trigger_detach_poll_func(indio_dev->trig,
	indio_dev->pollfunc);
	}
	EXPORT_SYMBOL(iio_triggered_buffer_predisable);