[mirror_ubuntu-hirsute-kernel.git] / drivers / staging / iio / industrialio-trigger.c

/* 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 "iio.h"
#include "trigger.h"
#include "iio_core.h"
#include "iio_core_trigger.h"
#include "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 = dev_get_drvdata(dev);
	return sprintf(buf, "%s\n", trig->name);
}

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

/**
 * iio_trigger_register_sysfs() - create a device for this trigger
 * @trig_info:	the trigger
 *
 * Also adds any control attribute registered by the trigger driver
 **/
static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
{
	return sysfs_add_file_to_group(&trig_info->dev.kobj,
				       &dev_attr_name.attr,
				       NULL);
}

static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
{
	sysfs_remove_file_from_group(&trig_info->dev.kobj,
					   &dev_attr_name.attr,
					   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;

	ret = iio_trigger_register_sysfs(trig_info);
	if (ret)
		goto error_device_del;

	/* 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_device_del:
	device_del(&trig_info->dev);
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);

	iio_trigger_unregister_sysfs(trig_info);
	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 (trig->ops && trig->ops->set_trigger_state && notinuse)
		ret = trig->ops->set_trigger_state(trig, true);

	return ret;
}

static int iio_trigger_dettach_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_currrent() - 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 *dev_info = dev_get_drvdata(dev);

	if (dev_info->trig)
		return sprintf(buf, "%s\n", dev_info->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 *dev_info = dev_get_drvdata(dev);
	struct iio_trigger *oldtrig = dev_info->trig;
	struct iio_trigger *trig;
	int ret;

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

	trig = iio_trigger_find_by_name(buf, len);

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

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

	dev_info->trig = trig;

	if (oldtrig && dev_info->trig != oldtrig)
		iio_put_trigger(oldtrig);
	if (dev_info->trig)
		iio_get_trigger(dev_info->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,
};

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_allocate_trigger(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);
		dev_set_drvdata(&trig->dev, (void *)trig);

		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_allocate_trigger);

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

int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
{
	dev_info->groups[dev_info->groupcounter++] =
		&iio_trigger_consumer_attr_group;

	return 0;
}

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

int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
{
	return indio_dev->trig
		? iio_trigger_attach_poll_func(indio_dev->trig,
					       indio_dev->pollfunc)
		: 0;
}
EXPORT_SYMBOL(iio_triggered_buffer_postenable);

int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
{
	return indio_dev->trig
		? iio_trigger_dettach_poll_func(indio_dev->trig,
						indio_dev->pollfunc)
		: 0;
}
EXPORT_SYMBOL(iio_triggered_buffer_predisable);
Commit	Line	Data
1637db44 JC	1	/* The industrial I/O core, trigger handling functions
	2	*
	3	* Copyright (c) 2008 Jonathan Cameron
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License version 2 as published by
	7	* the Free Software Foundation.
	8	*/
	9
	10	#include <linux/kernel.h>
1637db44 JC	11	#include <linux/idr.h>
	12	#include <linux/err.h>
	13	#include <linux/device.h>
	14	#include <linux/interrupt.h>
	15	#include <linux/list.h>
5a0e3ad6	16	#include <linux/slab.h>
1637db44 JC	17
	18	#include "iio.h"
	19	#include "trigger.h"
df9c1c42	20	#include "iio_core.h"
6aea1c36	21	#include "iio_core_trigger.h"
3f72395e	22	#include "trigger_consumer.h"
1637db44 JC	23
	24	/* RFC - Question of approach
	25	* Make the common case (single sensor single trigger)
	26	* simple by starting trigger capture from when first sensors
	27	* is added.
	28	*
	29	* Complex simultaneous start requires use of 'hold' functionality
	30	* of the trigger. (not implemented)
	31	*
	32	* Any other suggestions?
	33	*/
	34
47c24fdd	35	static DEFINE_IDA(iio_trigger_ida);
1637db44 JC	36
	37	/* Single list of all available triggers */
	38	static LIST_HEAD(iio_trigger_list);
	39	static DEFINE_MUTEX(iio_trigger_list_lock);
	40
59c85e82 JC	41	/**
	42	* iio_trigger_read_name() - retrieve useful identifying name
	43	**/
	44	static ssize_t iio_trigger_read_name(struct device *dev,
	45	struct device_attribute *attr,
	46	char *buf)
	47	{
	48	struct iio_trigger *trig = dev_get_drvdata(dev);
	49	return sprintf(buf, "%s\n", trig->name);
	50	}
	51
	52	static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
	53
1637db44 JC	54	/**
	55	* iio_trigger_register_sysfs() - create a device for this trigger
	56	* @trig_info: the trigger
	57	*
	58	* Also adds any control attribute registered by the trigger driver
	59	**/
	60	static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
	61	{
59c85e82 JC	62	return sysfs_add_file_to_group(&trig_info->dev.kobj,
	63	&dev_attr_name.attr,
	64	NULL);
1637db44 JC	65	}
	66
	67	static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
	68	{
59c85e82 JC	69	sysfs_remove_file_from_group(&trig_info->dev.kobj,
	70	&dev_attr_name.attr,
	71	NULL);
1637db44 JC	72	}
1637db44 JC	73
1637db44 JC	74	int iio_trigger_register(struct iio_trigger *trig_info)
	75	{
	76	int ret;
	77
47c24fdd JC	78	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
	79	if (trig_info->id < 0) {
	80	ret = trig_info->id;
1637db44	81	goto error_ret;
47c24fdd	82	}
1637db44 JC	83	/* Set the name used for the sysfs directory etc */
	84	dev_set_name(&trig_info->dev, "trigger%ld",
	85	(unsigned long) trig_info->id);
	86
	87	ret = device_add(&trig_info->dev);
	88	if (ret)
	89	goto error_unregister_id;
	90
	91	ret = iio_trigger_register_sysfs(trig_info);
	92	if (ret)
	93	goto error_device_del;
	94
	95	/* Add to list of available triggers held by the IIO core */
	96	mutex_lock(&iio_trigger_list_lock);
	97	list_add_tail(&trig_info->list, &iio_trigger_list);
	98	mutex_unlock(&iio_trigger_list_lock);
	99
	100	return 0;
	101
	102	error_device_del:
	103	device_del(&trig_info->dev);
	104	error_unregister_id:
47c24fdd	105	ida_simple_remove(&iio_trigger_ida, trig_info->id);
1637db44 JC	106	error_ret:
	107	return ret;
	108	}
	109	EXPORT_SYMBOL(iio_trigger_register);
	110
	111	void iio_trigger_unregister(struct iio_trigger *trig_info)
	112	{
1637db44	113	mutex_lock(&iio_trigger_list_lock);
582e5489	114	list_del(&trig_info->list);
1637db44 JC	115	mutex_unlock(&iio_trigger_list_lock);
	116
	117	iio_trigger_unregister_sysfs(trig_info);
47c24fdd	118	ida_simple_remove(&iio_trigger_ida, trig_info->id);
1637db44 JC	119	/* Possible issue in here */
	120	device_unregister(&trig_info->dev);
	121	}
	122	EXPORT_SYMBOL(iio_trigger_unregister);
	123
f6517f22 JC	124	static struct iio_trigger iio_trigger_find_by_name(const char name,
f6517f22 JC	125	size_t len)
1637db44	126	{
f6517f22	127	struct iio_trigger trig = NULL, iter;
7c327857	128
1637db44	129	mutex_lock(&iio_trigger_list_lock);
f6517f22 JC	130	list_for_each_entry(iter, &iio_trigger_list, list)
	131	if (sysfs_streq(iter->name, name)) {
	132	trig = iter;
1637db44 JC	133	break;
1637db44 JC	134	}
1637db44 JC	135	mutex_unlock(&iio_trigger_list_lock);
1637db44 JC	136
f6517f22	137	return trig;
5f87404d	138	}
1637db44	139
7b2c33b1	140	void iio_trigger_poll(struct iio_trigger *trig, s64 time)
1637db44	141	{
d96d1337	142	int i;
cb6c89a0	143	if (!trig->use_count)
d96d1337 JC	144	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
	145	if (trig->subirqs[i].enabled) {
	146	trig->use_count++;
	147	generic_handle_irq(trig->subirq_base + i);
	148	}
1637db44 JC	149	}
1637db44 JC	150	EXPORT_SYMBOL(iio_trigger_poll);
8384d957 JC	151
	152	irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
	153	{
	154	iio_trigger_poll(private, iio_get_time_ns());
	155	return IRQ_HANDLED;
	156	}
	157	EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
1637db44	158
1f785681 JC	159	void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
	160	{
	161	int i;
	162	if (!trig->use_count) {
	163	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
	164	if (trig->subirqs[i].enabled) {
	165	trig->use_count++;
	166	handle_nested_irq(trig->subirq_base + i);
	167	}
	168	}
	169	}
	170	EXPORT_SYMBOL(iio_trigger_poll_chained);
	171
1637db44 JC	172	void iio_trigger_notify_done(struct iio_trigger *trig)
	173	{
	174	trig->use_count--;
d29f73db JC	175	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
d29f73db JC	176	if (trig->ops->try_reenable(trig)) {
1637db44	177	/* Missed and interrupt so launch new poll now */
7b2c33b1	178	iio_trigger_poll(trig, 0);
1637db44 JC	179	}
	180	}
	181	EXPORT_SYMBOL(iio_trigger_notify_done);
	182
1637db44	183	/* Trigger Consumer related functions */
208b813c JC	184	static int iio_trigger_get_irq(struct iio_trigger *trig)
	185	{
	186	int ret;
	187	mutex_lock(&trig->pool_lock);
	188	ret = bitmap_find_free_region(trig->pool,
	189	CONFIG_IIO_CONSUMERS_PER_TRIGGER,
	190	ilog2(1));
	191	mutex_unlock(&trig->pool_lock);
	192	if (ret >= 0)
	193	ret += trig->subirq_base;
	194
	195	return ret;
	196	}
	197
	198	static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
	199	{
	200	mutex_lock(&trig->pool_lock);
	201	clear_bit(irq - trig->subirq_base, trig->pool);
	202	mutex_unlock(&trig->pool_lock);
	203	}
1637db44 JC	204
	205	/* Complexity in here. With certain triggers (datardy) an acknowledgement
	206	* may be needed if the pollfuncs do not include the data read for the
	207	* triggering device.
	208	* This is not currently handled. Alternative of not enabling trigger unless
	209	* the relevant function is in there may be the best option.
	210	*/
	211	/* Worth protecting against double additions?*/
208b813c JC	212	static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
208b813c JC	213	struct iio_poll_func *pf)
1637db44 JC	214	{
1637db44 JC	215	int ret = 0;
51c060a0 JC	216	bool notinuse
	217	= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
	218
f60c4a02 JC	219	/* Prevent the module being removed whilst attached to a trigger */
f60c4a02 JC	220	__module_get(pf->indio_dev->info->driver_module);
51c060a0 JC	221	pf->irq = iio_trigger_get_irq(trig);
	222	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
	223	pf->type, pf->name,
	224	pf);
d29f73db JC	225	if (trig->ops && trig->ops->set_trigger_state && notinuse)
d29f73db JC	226	ret = trig->ops->set_trigger_state(trig, true);
d96d1337	227
1637db44 JC	228	return ret;
1637db44 JC	229	}
1637db44	230
208b813c JC	231	static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
208b813c JC	232	struct iio_poll_func *pf)
1637db44	233	{
51c060a0 JC	234	int ret = 0;
	235	bool no_other_users
	236	= (bitmap_weight(trig->pool,
	237	CONFIG_IIO_CONSUMERS_PER_TRIGGER)
	238	== 1);
d29f73db JC	239	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
d29f73db JC	240	ret = trig->ops->set_trigger_state(trig, false);
51c060a0 JC	241	if (ret)
51c060a0 JC	242	goto error_ret;
1637db44	243	}
51c060a0 JC	244	iio_trigger_put_irq(trig, pf->irq);
51c060a0 JC	245	free_irq(pf->irq, pf);
f60c4a02	246	module_put(pf->indio_dev->info->driver_module);
1637db44 JC	247
	248	error_ret:
	249	return ret;
	250	}
1637db44	251
d96d1337 JC	252	irqreturn_t iio_pollfunc_store_time(int irq, void *p)
	253	{
	254	struct iio_poll_func *pf = p;
	255	pf->timestamp = iio_get_time_ns();
	256	return IRQ_WAKE_THREAD;
	257	}
	258	EXPORT_SYMBOL(iio_pollfunc_store_time);
	259
21b185f8 JC	260	struct iio_poll_func
	261	iio_alloc_pollfunc(irqreturn_t (h)(int irq, void *p),
	262	irqreturn_t (thread)(int irq, void p),
	263	int type,
e65bc6ac	264	struct iio_dev *indio_dev,
21b185f8 JC	265	const char *fmt,
	266	...)
	267	{
	268	va_list vargs;
	269	struct iio_poll_func *pf;
	270
	271	pf = kmalloc(sizeof *pf, GFP_KERNEL);
	272	if (pf == NULL)
	273	return NULL;
	274	va_start(vargs, fmt);
	275	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
	276	va_end(vargs);
	277	if (pf->name == NULL) {
	278	kfree(pf);
	279	return NULL;
	280	}
	281	pf->h = h;
	282	pf->thread = thread;
	283	pf->type = type;
e65bc6ac	284	pf->indio_dev = indio_dev;
21b185f8 JC	285
	286	return pf;
	287	}
	288	EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
	289
	290	void iio_dealloc_pollfunc(struct iio_poll_func *pf)
	291	{
	292	kfree(pf->name);
	293	kfree(pf);
	294	}
	295	EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
	296
1637db44	297	/**
751a3700	298	* iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
1637db44 JC	299	*
	300	* For trigger consumers the current_trigger interface allows the trigger
	301	* used by the device to be queried.
	302	**/
	303	static ssize_t iio_trigger_read_current(struct device *dev,
	304	struct device_attribute *attr,
	305	char *buf)
	306	{
	307	struct iio_dev *dev_info = dev_get_drvdata(dev);
cb6c89a0	308
1637db44	309	if (dev_info->trig)
cb6c89a0 JC	310	return sprintf(buf, "%s\n", dev_info->trig->name);
cb6c89a0 JC	311	return 0;
1637db44 JC	312	}
	313
	314	/**
	315	* iio_trigger_write_current() trigger consumer sysfs set current trigger
	316	*
	317	* For trigger consumers the current_trigger interface allows the trigger
	318	* used for this device to be specified at run time based on the triggers
	319	* name.
	320	**/
	321	static ssize_t iio_trigger_write_current(struct device *dev,
	322	struct device_attribute *attr,
	323	const char *buf,
	324	size_t len)
	325	{
	326	struct iio_dev *dev_info = dev_get_drvdata(dev);
	327	struct iio_trigger *oldtrig = dev_info->trig;
43a4360e MH	328	struct iio_trigger *trig;
	329	int ret;
	330
1637db44	331	mutex_lock(&dev_info->mlock);
ec3afa40	332	if (dev_info->currentmode == INDIO_BUFFER_TRIGGERED) {
1637db44 JC	333	mutex_unlock(&dev_info->mlock);
	334	return -EBUSY;
	335	}
	336	mutex_unlock(&dev_info->mlock);
	337
43a4360e MH	338	trig = iio_trigger_find_by_name(buf, len);
	339
	340	if (trig && dev_info->info->validate_trigger) {
	341	ret = dev_info->info->validate_trigger(dev_info, trig);
	342	if (ret)
	343	return ret;
	344	}
	345
d29f73db JC	346	if (trig && trig->ops && trig->ops->validate_device) {
d29f73db JC	347	ret = trig->ops->validate_device(trig, dev_info);
43a4360e MH	348	if (ret)
	349	return ret;
	350	}
	351
	352	dev_info->trig = trig;
	353
1637db44 JC	354	if (oldtrig && dev_info->trig != oldtrig)
	355	iio_put_trigger(oldtrig);
	356	if (dev_info->trig)
	357	iio_get_trigger(dev_info->trig);
	358
	359	return len;
	360	}
	361
74112d3f GKH	362	static DEVICE_ATTR(current_trigger, S_IRUGO \| S_IWUSR,
	363	iio_trigger_read_current,
	364	iio_trigger_write_current);
1637db44 JC	365
	366	static struct attribute *iio_trigger_consumer_attrs[] = {
	367	&dev_attr_current_trigger.attr,
	368	NULL,
	369	};
	370
	371	static const struct attribute_group iio_trigger_consumer_attr_group = {
	372	.name = "trigger",
	373	.attrs = iio_trigger_consumer_attrs,
	374	};
	375
	376	static void iio_trig_release(struct device *device)
	377	{
	378	struct iio_trigger *trig = to_iio_trigger(device);
d96d1337 JC	379	int i;
	380
	381	if (trig->subirq_base) {
	382	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
	383	irq_modify_status(trig->subirq_base + i,
	384	IRQ_NOAUTOEN,
	385	IRQ_NOREQUEST \| IRQ_NOPROBE);
	386	irq_set_chip(trig->subirq_base + i,
	387	NULL);
	388	irq_set_handler(trig->subirq_base + i,
	389	NULL);
	390	}
	391
	392	irq_free_descs(trig->subirq_base,
	393	CONFIG_IIO_CONSUMERS_PER_TRIGGER);
	394	}
59c85e82	395	kfree(trig->name);
1637db44	396	kfree(trig);
1637db44 JC	397	}
	398
	399	static struct device_type iio_trig_type = {
	400	.release = iio_trig_release,
	401	};
	402
d96d1337 JC	403	static void iio_trig_subirqmask(struct irq_data *d)
	404	{
	405	struct irq_chip *chip = irq_data_get_irq_chip(d);
	406	struct iio_trigger *trig
	407	= container_of(chip,
	408	struct iio_trigger, subirq_chip);
	409	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
	410	}
	411
	412	static void iio_trig_subirqunmask(struct irq_data *d)
	413	{
	414	struct irq_chip *chip = irq_data_get_irq_chip(d);
	415	struct iio_trigger *trig
	416	= container_of(chip,
	417	struct iio_trigger, subirq_chip);
	418	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
	419	}
	420
59c85e82	421	struct iio_trigger iio_allocate_trigger(const char fmt, ...)
1637db44	422	{
59c85e82	423	va_list vargs;
1637db44 JC	424	struct iio_trigger *trig;
	425	trig = kzalloc(sizeof *trig, GFP_KERNEL);
	426	if (trig) {
d96d1337	427	int i;
1637db44	428	trig->dev.type = &iio_trig_type;
5aaaeba8	429	trig->dev.bus = &iio_bus_type;
1637db44 JC	430	device_initialize(&trig->dev);
1637db44 JC	431	dev_set_drvdata(&trig->dev, (void *)trig);
d96d1337	432
59c85e82 JC	433	mutex_init(&trig->pool_lock);
	434	trig->subirq_base
	435	= irq_alloc_descs(-1, 0,
	436	CONFIG_IIO_CONSUMERS_PER_TRIGGER,
	437	0);
	438	if (trig->subirq_base < 0) {
	439	kfree(trig);
	440	return NULL;
	441	}
	442	va_start(vargs, fmt);
	443	trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
	444	va_end(vargs);
	445	if (trig->name == NULL) {
	446	irq_free_descs(trig->subirq_base,
	447	CONFIG_IIO_CONSUMERS_PER_TRIGGER);
	448	kfree(trig);
	449	return NULL;
	450	}
	451	trig->subirq_chip.name = trig->name;
	452	trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
	453	trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
	454	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
	455	irq_set_chip(trig->subirq_base + i,
	456	&trig->subirq_chip);
	457	irq_set_handler(trig->subirq_base + i,
	458	&handle_simple_irq);
	459	irq_modify_status(trig->subirq_base + i,
	460	IRQ_NOREQUEST \| IRQ_NOAUTOEN,
	461	IRQ_NOPROBE);
d96d1337	462	}
5f9c035c	463	get_device(&trig->dev);
1637db44 JC	464	}
	465	return trig;
	466	}
	467	EXPORT_SYMBOL(iio_allocate_trigger);
	468
	469	void iio_free_trigger(struct iio_trigger *trig)
	470	{
	471	if (trig)
	472	put_device(&trig->dev);
	473	}
	474	EXPORT_SYMBOL(iio_free_trigger);
	475
	476	int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
	477	{
26d25ae3 JC	478	dev_info->groups[dev_info->groupcounter++] =
	479	&iio_trigger_consumer_attr_group;
	480
	481	return 0;
1637db44	482	}
1637db44	483
cb6c89a0	484	void iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
1637db44	485	{
5f9c035c JC	486	/* Clean up and associated but not attached triggers references */
	487	if (dev_info->trig)
	488	iio_put_trigger(dev_info->trig);
1637db44	489	}
1637db44	490
3b99fb76	491	int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
c3db00cc JC	492	{
	493	return indio_dev->trig
	494	? iio_trigger_attach_poll_func(indio_dev->trig,
	495	indio_dev->pollfunc)
	496	: 0;
	497	}
3b99fb76	498	EXPORT_SYMBOL(iio_triggered_buffer_postenable);
c3db00cc	499
3b99fb76	500	int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
c3db00cc JC	501	{
	502	return indio_dev->trig
	503	? iio_trigger_dettach_poll_func(indio_dev->trig,
	504	indio_dev->pollfunc)
	505	: 0;
	506	}
3b99fb76	507	EXPORT_SYMBOL(iio_triggered_buffer_predisable);