[linux-2.6-block.git] / drivers / iio / industrialio-event.c

// SPDX-License-Identifier: GPL-2.0-only
/* Industrial I/O event handling
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * Based on elements of hwmon and input subsystems.
 */

#include <linux/anon_inodes.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/iio/iio.h>
#include <linux/iio/iio-opaque.h>
#include "iio_core.h"
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>

/**
 * struct iio_event_interface - chrdev interface for an event line
 * @wait:		wait queue to allow blocking reads of events
 * @det_events:		list of detected events
 * @dev_attr_list:	list of event interface sysfs attribute
 * @flags:		file operations related flags including busy flag.
 * @group:		event interface sysfs attribute group
 * @read_lock:		lock to protect kfifo read operations
 * @ioctl_handler:	handler for event ioctl() calls
 */
struct iio_event_interface {
	wait_queue_head_t	wait;
	DECLARE_KFIFO(det_events, struct iio_event_data, 16);

	struct list_head	dev_attr_list;
	unsigned long		flags;
	struct attribute_group	group;
	struct mutex		read_lock;
	struct iio_ioctl_handler	ioctl_handler;
};

bool iio_event_enabled(const struct iio_event_interface *ev_int)
{
	return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
}

/**
 * iio_push_event() - try to add event to the list for userspace reading
 * @indio_dev:		IIO device structure
 * @ev_code:		What event
 * @timestamp:		When the event occurred
 *
 * Note: The caller must make sure that this function is not running
 * concurrently for the same indio_dev more than once.
 *
 * This function may be safely used as soon as a valid reference to iio_dev has
 * been obtained via iio_device_alloc(), but any events that are submitted
 * before iio_device_register() has successfully completed will be silently
 * discarded.
 **/
int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	struct iio_event_data ev;
	int copied;

	if (!ev_int)
		return 0;

	/* Does anyone care? */
	if (iio_event_enabled(ev_int)) {

		ev.id = ev_code;
		ev.timestamp = timestamp;

		copied = kfifo_put(&ev_int->det_events, ev);
		if (copied != 0)
			wake_up_poll(&ev_int->wait, EPOLLIN);
	}

	return 0;
}
EXPORT_SYMBOL(iio_push_event);

/**
 * iio_event_poll() - poll the event queue to find out if it has data
 * @filep:	File structure pointer to identify the device
 * @wait:	Poll table pointer to add the wait queue on
 *
 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
 *	   or a negative error code on failure
 */
static __poll_t iio_event_poll(struct file *filep,
			     struct poll_table_struct *wait)
{
	struct iio_dev *indio_dev = filep->private_data;
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	__poll_t events = 0;

	if (!indio_dev->info)
		return events;

	poll_wait(filep, &ev_int->wait, wait);

	if (!kfifo_is_empty(&ev_int->det_events))
		events = EPOLLIN | EPOLLRDNORM;

	return events;
}

static ssize_t iio_event_chrdev_read(struct file *filep,
				     char __user *buf,
				     size_t count,
				     loff_t *f_ps)
{
	struct iio_dev *indio_dev = filep->private_data;
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	unsigned int copied;
	int ret;

	if (!indio_dev->info)
		return -ENODEV;

	if (count < sizeof(struct iio_event_data))
		return -EINVAL;

	do {
		if (kfifo_is_empty(&ev_int->det_events)) {
			if (filep->f_flags & O_NONBLOCK)
				return -EAGAIN;

			ret = wait_event_interruptible(ev_int->wait,
					!kfifo_is_empty(&ev_int->det_events) ||
					indio_dev->info == NULL);
			if (ret)
				return ret;
			if (indio_dev->info == NULL)
				return -ENODEV;
		}

		if (mutex_lock_interruptible(&ev_int->read_lock))
			return -ERESTARTSYS;
		ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
		mutex_unlock(&ev_int->read_lock);

		if (ret)
			return ret;

		/*
		 * If we couldn't read anything from the fifo (a different
		 * thread might have been faster) we either return -EAGAIN if
		 * the file descriptor is non-blocking, otherwise we go back to
		 * sleep and wait for more data to arrive.
		 */
		if (copied == 0 && (filep->f_flags & O_NONBLOCK))
			return -EAGAIN;

	} while (copied == 0);

	return copied;
}

static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
{
	struct iio_dev *indio_dev = filep->private_data;
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;

	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);

	iio_device_put(indio_dev);

	return 0;
}

static const struct file_operations iio_event_chrdev_fileops = {
	.read =  iio_event_chrdev_read,
	.poll =  iio_event_poll,
	.release = iio_event_chrdev_release,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
};

static int iio_event_getfd(struct iio_dev *indio_dev)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	int fd;

	if (ev_int == NULL)
		return -ENODEV;

	fd = mutex_lock_interruptible(&indio_dev->mlock);
	if (fd)
		return fd;

	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
		fd = -EBUSY;
		goto unlock;
	}

	iio_device_get(indio_dev);

	fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
				indio_dev, O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
		iio_device_put(indio_dev);
	} else {
		kfifo_reset_out(&ev_int->det_events);
	}

unlock:
	mutex_unlock(&indio_dev->mlock);
	return fd;
}

static const char * const iio_ev_type_text[] = {
	[IIO_EV_TYPE_THRESH] = "thresh",
	[IIO_EV_TYPE_MAG] = "mag",
	[IIO_EV_TYPE_ROC] = "roc",
	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
	[IIO_EV_TYPE_CHANGE] = "change",
};

static const char * const iio_ev_dir_text[] = {
	[IIO_EV_DIR_EITHER] = "either",
	[IIO_EV_DIR_RISING] = "rising",
	[IIO_EV_DIR_FALLING] = "falling"
};

static const char * const iio_ev_info_text[] = {
	[IIO_EV_INFO_ENABLE] = "en",
	[IIO_EV_INFO_VALUE] = "value",
	[IIO_EV_INFO_HYSTERESIS] = "hysteresis",
	[IIO_EV_INFO_PERIOD] = "period",
	[IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
	[IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
};

static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
{
	return attr->c->event_spec[attr->address & 0xffff].dir;
}

static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
{
	return attr->c->event_spec[attr->address & 0xffff].type;
}

static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
{
	return (attr->address >> 16) & 0xffff;
}

static ssize_t iio_ev_state_store(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_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret;
	bool val;

	ret = strtobool(buf, &val);
	if (ret < 0)
		return ret;

	ret = indio_dev->info->write_event_config(indio_dev,
		this_attr->c, iio_ev_attr_type(this_attr),
		iio_ev_attr_dir(this_attr), val);

	return (ret < 0) ? ret : len;
}

static ssize_t iio_ev_state_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int val;

	val = indio_dev->info->read_event_config(indio_dev,
		this_attr->c, iio_ev_attr_type(this_attr),
		iio_ev_attr_dir(this_attr));
	if (val < 0)
		return val;
	else
		return sprintf(buf, "%d\n", val);
}

static ssize_t iio_ev_value_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int val, val2, val_arr[2];
	int ret;

	ret = indio_dev->info->read_event_value(indio_dev,
		this_attr->c, iio_ev_attr_type(this_attr),
		iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
		&val, &val2);
	if (ret < 0)
		return ret;
	val_arr[0] = val;
	val_arr[1] = val2;
	return iio_format_value(buf, ret, 2, val_arr);
}

static ssize_t iio_ev_value_store(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_dev_attr *this_attr = to_iio_dev_attr(attr);
	int val, val2;
	int ret;

	if (!indio_dev->info->write_event_value)
		return -EINVAL;

	ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
	if (ret)
		return ret;
	ret = indio_dev->info->write_event_value(indio_dev,
		this_attr->c, iio_ev_attr_type(this_attr),
		iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
		val, val2);
	if (ret < 0)
		return ret;

	return len;
}

static int iio_device_add_event(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, unsigned int spec_index,
	enum iio_event_type type, enum iio_event_direction dir,
	enum iio_shared_by shared_by, const unsigned long *mask)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	ssize_t (*show)(struct device *, struct device_attribute *, char *);
	ssize_t (*store)(struct device *, struct device_attribute *,
		const char *, size_t);
	unsigned int attrcount = 0;
	unsigned int i;
	char *postfix;
	int ret;

	for_each_set_bit(i, mask, sizeof(*mask)*8) {
		if (i >= ARRAY_SIZE(iio_ev_info_text))
			return -EINVAL;
		if (dir != IIO_EV_DIR_NONE)
			postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
					iio_ev_type_text[type],
					iio_ev_dir_text[dir],
					iio_ev_info_text[i]);
		else
			postfix = kasprintf(GFP_KERNEL, "%s_%s",
					iio_ev_type_text[type],
					iio_ev_info_text[i]);
		if (postfix == NULL)
			return -ENOMEM;

		if (i == IIO_EV_INFO_ENABLE) {
			show = iio_ev_state_show;
			store = iio_ev_state_store;
		} else {
			show = iio_ev_value_show;
			store = iio_ev_value_store;
		}

		ret = __iio_add_chan_devattr(postfix, chan, show, store,
			 (i << 16) | spec_index, shared_by, &indio_dev->dev,
			&iio_dev_opaque->event_interface->dev_attr_list);
		kfree(postfix);

		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
			continue;

		if (ret)
			return ret;

		attrcount++;
	}

	return attrcount;
}

static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan)
{
	int ret = 0, i, attrcount = 0;
	enum iio_event_direction dir;
	enum iio_event_type type;

	for (i = 0; i < chan->num_event_specs; i++) {
		type = chan->event_spec[i].type;
		dir = chan->event_spec[i].dir;

		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
			IIO_SEPARATE, &chan->event_spec[i].mask_separate);
		if (ret < 0)
			return ret;
		attrcount += ret;

		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
			IIO_SHARED_BY_TYPE,
			&chan->event_spec[i].mask_shared_by_type);
		if (ret < 0)
			return ret;
		attrcount += ret;

		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
			IIO_SHARED_BY_DIR,
			&chan->event_spec[i].mask_shared_by_dir);
		if (ret < 0)
			return ret;
		attrcount += ret;

		ret = iio_device_add_event(indio_dev, chan, i, type, dir,
			IIO_SHARED_BY_ALL,
			&chan->event_spec[i].mask_shared_by_all);
		if (ret < 0)
			return ret;
		attrcount += ret;
	}
	ret = attrcount;
	return ret;
}

static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
{
	int j, ret, attrcount = 0;

	/* Dynamically created from the channels array */
	for (j = 0; j < indio_dev->num_channels; j++) {
		ret = iio_device_add_event_sysfs(indio_dev,
						 &indio_dev->channels[j]);
		if (ret < 0)
			return ret;
		attrcount += ret;
	}
	return attrcount;
}

static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
{
	int j;

	for (j = 0; j < indio_dev->num_channels; j++) {
		if (indio_dev->channels[j].num_event_specs != 0)
			return true;
	}
	return false;
}

static void iio_setup_ev_int(struct iio_event_interface *ev_int)
{
	INIT_KFIFO(ev_int->det_events);
	init_waitqueue_head(&ev_int->wait);
	mutex_init(&ev_int->read_lock);
}

static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
			    unsigned int cmd, unsigned long arg)
{
	int __user *ip = (int __user *)arg;
	int fd;

	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
		fd = iio_event_getfd(indio_dev);
		if (fd < 0)
			return fd;
		if (copy_to_user(ip, &fd, sizeof(fd)))
			return -EFAULT;
		return 0;
	}

	return IIO_IOCTL_UNHANDLED;
}

static const char *iio_event_group_name = "events";
int iio_device_register_eventset(struct iio_dev *indio_dev)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int;
	struct iio_dev_attr *p;
	int ret = 0, attrcount_orig = 0, attrcount, attrn;
	struct attribute **attr;

	if (!(indio_dev->info->event_attrs ||
	      iio_check_for_dynamic_events(indio_dev)))
		return 0;

	ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
	if (ev_int == NULL)
		return -ENOMEM;

	iio_dev_opaque->event_interface = ev_int;

	INIT_LIST_HEAD(&ev_int->dev_attr_list);

	iio_setup_ev_int(ev_int);
	if (indio_dev->info->event_attrs != NULL) {
		attr = indio_dev->info->event_attrs->attrs;
		while (*attr++ != NULL)
			attrcount_orig++;
	}
	attrcount = attrcount_orig;
	if (indio_dev->channels) {
		ret = __iio_add_event_config_attrs(indio_dev);
		if (ret < 0)
			goto error_free_setup_event_lines;
		attrcount += ret;
	}

	ev_int->group.name = iio_event_group_name;
	ev_int->group.attrs = kcalloc(attrcount + 1,
				      sizeof(ev_int->group.attrs[0]),
				      GFP_KERNEL);
	if (ev_int->group.attrs == NULL) {
		ret = -ENOMEM;
		goto error_free_setup_event_lines;
	}
	if (indio_dev->info->event_attrs)
		memcpy(ev_int->group.attrs,
		       indio_dev->info->event_attrs->attrs,
		       sizeof(ev_int->group.attrs[0]) * attrcount_orig);
	attrn = attrcount_orig;
	/* Add all elements from the list. */
	list_for_each_entry(p, &ev_int->dev_attr_list, l)
		ev_int->group.attrs[attrn++] = &p->dev_attr.attr;

	ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group);
	if (ret)
		goto error_free_setup_event_lines;

	ev_int->ioctl_handler.ioctl = iio_event_ioctl;
	iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev,
					  &ev_int->ioctl_handler);

	return 0;

error_free_setup_event_lines:
	iio_free_chan_devattr_list(&ev_int->dev_attr_list);
	kfree(ev_int);
	iio_dev_opaque->event_interface = NULL;
	return ret;
}

/**
 * iio_device_wakeup_eventset - Wakes up the event waitqueue
 * @indio_dev: The IIO device
 *
 * Wakes up the event waitqueue used for poll() and blocking read().
 * Should usually be called when the device is unregistered.
 */
void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

	if (iio_dev_opaque->event_interface == NULL)
		return;
	wake_up(&iio_dev_opaque->event_interface->wait);
}

void iio_device_unregister_eventset(struct iio_dev *indio_dev)
{
	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;

	if (ev_int == NULL)
		return;

	iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler);
	iio_free_chan_devattr_list(&ev_int->dev_attr_list);
	kfree(ev_int->group.attrs);
	kfree(ev_int);
	iio_dev_opaque->event_interface = NULL;
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/* Industrial I/O event handling
	3	*
	4	* Copyright (c) 2008 Jonathan Cameron
	5	*
	6	* Based on elements of hwmon and input subsystems.
	7	*/
	8
	9	#include <linux/anon_inodes.h>
	10	#include <linux/device.h>
	11	#include <linux/fs.h>
	12	#include <linux/kernel.h>
	13	#include <linux/kfifo.h>
	14	#include <linux/module.h>
	15	#include <linux/poll.h>
	16	#include <linux/sched.h>
	17	#include <linux/slab.h>
	18	#include <linux/uaccess.h>
	19	#include <linux/wait.h>
	20	#include <linux/iio/iio.h>
	21	#include <linux/iio/iio-opaque.h>
	22	#include "iio_core.h"
	23	#include <linux/iio/sysfs.h>
	24	#include <linux/iio/events.h>
	25
	26	/**
	27	* struct iio_event_interface - chrdev interface for an event line
	28	* @wait: wait queue to allow blocking reads of events
	29	* @det_events: list of detected events
	30	* @dev_attr_list: list of event interface sysfs attribute
	31	* @flags: file operations related flags including busy flag.
	32	* @group: event interface sysfs attribute group
	33	* @read_lock: lock to protect kfifo read operations
	34	* @ioctl_handler: handler for event ioctl() calls
	35	*/
	36	struct iio_event_interface {
	37	wait_queue_head_t wait;
	38	DECLARE_KFIFO(det_events, struct iio_event_data, 16);
	39
	40	struct list_head dev_attr_list;
	41	unsigned long flags;
	42	struct attribute_group group;
	43	struct mutex read_lock;
	44	struct iio_ioctl_handler ioctl_handler;
	45	};
	46
	47	bool iio_event_enabled(const struct iio_event_interface *ev_int)
	48	{
	49	return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
	50	}
	51
	52	/**
	53	* iio_push_event() - try to add event to the list for userspace reading
	54	* @indio_dev: IIO device structure
	55	* @ev_code: What event
	56	* @timestamp: When the event occurred
	57	*
	58	* Note: The caller must make sure that this function is not running
	59	* concurrently for the same indio_dev more than once.
	60	*
	61	* This function may be safely used as soon as a valid reference to iio_dev has
	62	* been obtained via iio_device_alloc(), but any events that are submitted
	63	* before iio_device_register() has successfully completed will be silently
	64	* discarded.
	65	**/
	66	int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
	67	{
	68	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	69	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	70	struct iio_event_data ev;
	71	int copied;
	72
	73	if (!ev_int)
	74	return 0;
	75
	76	/* Does anyone care? */
	77	if (iio_event_enabled(ev_int)) {
	78
	79	ev.id = ev_code;
	80	ev.timestamp = timestamp;
	81
	82	copied = kfifo_put(&ev_int->det_events, ev);
	83	if (copied != 0)
	84	wake_up_poll(&ev_int->wait, EPOLLIN);
	85	}
	86
	87	return 0;
	88	}
	89	EXPORT_SYMBOL(iio_push_event);
	90
	91	/**
	92	* iio_event_poll() - poll the event queue to find out if it has data
	93	* @filep: File structure pointer to identify the device
	94	* @wait: Poll table pointer to add the wait queue on
	95	*
	96	* Return: (EPOLLIN \| EPOLLRDNORM) if data is available for reading
	97	* or a negative error code on failure
	98	*/
	99	static __poll_t iio_event_poll(struct file *filep,
	100	struct poll_table_struct *wait)
	101	{
	102	struct iio_dev *indio_dev = filep->private_data;
	103	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	104	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	105	__poll_t events = 0;
	106
	107	if (!indio_dev->info)
	108	return events;
	109
	110	poll_wait(filep, &ev_int->wait, wait);
	111
	112	if (!kfifo_is_empty(&ev_int->det_events))
	113	events = EPOLLIN \| EPOLLRDNORM;
	114
	115	return events;
	116	}
	117
	118	static ssize_t iio_event_chrdev_read(struct file *filep,
	119	char __user *buf,
	120	size_t count,
	121	loff_t *f_ps)
	122	{
	123	struct iio_dev *indio_dev = filep->private_data;
	124	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	125	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	126	unsigned int copied;
	127	int ret;
	128
	129	if (!indio_dev->info)
	130	return -ENODEV;
	131
	132	if (count < sizeof(struct iio_event_data))
	133	return -EINVAL;
	134
	135	do {
	136	if (kfifo_is_empty(&ev_int->det_events)) {
	137	if (filep->f_flags & O_NONBLOCK)
	138	return -EAGAIN;
	139
	140	ret = wait_event_interruptible(ev_int->wait,
	141	!kfifo_is_empty(&ev_int->det_events) \|\|
	142	indio_dev->info == NULL);
	143	if (ret)
	144	return ret;
	145	if (indio_dev->info == NULL)
	146	return -ENODEV;
	147	}
	148
	149	if (mutex_lock_interruptible(&ev_int->read_lock))
	150	return -ERESTARTSYS;
	151	ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
	152	mutex_unlock(&ev_int->read_lock);
	153
	154	if (ret)
	155	return ret;
	156
	157	/*
	158	* If we couldn't read anything from the fifo (a different
	159	* thread might have been faster) we either return -EAGAIN if
	160	* the file descriptor is non-blocking, otherwise we go back to
	161	* sleep and wait for more data to arrive.
	162	*/
	163	if (copied == 0 && (filep->f_flags & O_NONBLOCK))
	164	return -EAGAIN;
	165
	166	} while (copied == 0);
	167
	168	return copied;
	169	}
	170
	171	static int iio_event_chrdev_release(struct inode inode, struct file filep)
	172	{
	173	struct iio_dev *indio_dev = filep->private_data;
	174	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	175	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	176
	177	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
	178
	179	iio_device_put(indio_dev);
	180
	181	return 0;
	182	}
	183
	184	static const struct file_operations iio_event_chrdev_fileops = {
	185	.read = iio_event_chrdev_read,
	186	.poll = iio_event_poll,
	187	.release = iio_event_chrdev_release,
	188	.owner = THIS_MODULE,
	189	.llseek = noop_llseek,
	190	};
	191
	192	static int iio_event_getfd(struct iio_dev *indio_dev)
	193	{
	194	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	195	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	196	int fd;
	197
	198	if (ev_int == NULL)
	199	return -ENODEV;
	200
	201	fd = mutex_lock_interruptible(&indio_dev->mlock);
	202	if (fd)
	203	return fd;
	204
	205	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
	206	fd = -EBUSY;
	207	goto unlock;
	208	}
	209
	210	iio_device_get(indio_dev);
	211
	212	fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
	213	indio_dev, O_RDONLY \| O_CLOEXEC);
	214	if (fd < 0) {
	215	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
	216	iio_device_put(indio_dev);
	217	} else {
	218	kfifo_reset_out(&ev_int->det_events);
	219	}
	220
	221	unlock:
	222	mutex_unlock(&indio_dev->mlock);
	223	return fd;
	224	}
	225
	226	static const char * const iio_ev_type_text[] = {
	227	[IIO_EV_TYPE_THRESH] = "thresh",
	228	[IIO_EV_TYPE_MAG] = "mag",
	229	[IIO_EV_TYPE_ROC] = "roc",
	230	[IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
	231	[IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
	232	[IIO_EV_TYPE_CHANGE] = "change",
	233	};
	234
	235	static const char * const iio_ev_dir_text[] = {
	236	[IIO_EV_DIR_EITHER] = "either",
	237	[IIO_EV_DIR_RISING] = "rising",
	238	[IIO_EV_DIR_FALLING] = "falling"
	239	};
	240
	241	static const char * const iio_ev_info_text[] = {
	242	[IIO_EV_INFO_ENABLE] = "en",
	243	[IIO_EV_INFO_VALUE] = "value",
	244	[IIO_EV_INFO_HYSTERESIS] = "hysteresis",
	245	[IIO_EV_INFO_PERIOD] = "period",
	246	[IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
	247	[IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
	248	};
	249
	250	static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
	251	{
	252	return attr->c->event_spec[attr->address & 0xffff].dir;
	253	}
	254
	255	static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
	256	{
	257	return attr->c->event_spec[attr->address & 0xffff].type;
	258	}
	259
	260	static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
	261	{
	262	return (attr->address >> 16) & 0xffff;
	263	}
	264
	265	static ssize_t iio_ev_state_store(struct device *dev,
	266	struct device_attribute *attr,
	267	const char *buf,
	268	size_t len)
	269	{
	270	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	271	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	272	int ret;
	273	bool val;
	274
	275	ret = strtobool(buf, &val);
	276	if (ret < 0)
	277	return ret;
	278
	279	ret = indio_dev->info->write_event_config(indio_dev,
	280	this_attr->c, iio_ev_attr_type(this_attr),
	281	iio_ev_attr_dir(this_attr), val);
	282
	283	return (ret < 0) ? ret : len;
	284	}
	285
	286	static ssize_t iio_ev_state_show(struct device *dev,
	287	struct device_attribute *attr,
	288	char *buf)
	289	{
	290	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	291	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	292	int val;
	293
	294	val = indio_dev->info->read_event_config(indio_dev,
	295	this_attr->c, iio_ev_attr_type(this_attr),
	296	iio_ev_attr_dir(this_attr));
	297	if (val < 0)
	298	return val;
	299	else
	300	return sprintf(buf, "%d\n", val);
	301	}
	302
	303	static ssize_t iio_ev_value_show(struct device *dev,
	304	struct device_attribute *attr,
	305	char *buf)
	306	{
	307	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	308	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	309	int val, val2, val_arr[2];
	310	int ret;
	311
	312	ret = indio_dev->info->read_event_value(indio_dev,
	313	this_attr->c, iio_ev_attr_type(this_attr),
	314	iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
	315	&val, &val2);
	316	if (ret < 0)
	317	return ret;
	318	val_arr[0] = val;
	319	val_arr[1] = val2;
	320	return iio_format_value(buf, ret, 2, val_arr);
	321	}
	322
	323	static ssize_t iio_ev_value_store(struct device *dev,
	324	struct device_attribute *attr,
	325	const char *buf,
	326	size_t len)
	327	{
	328	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	329	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	330	int val, val2;
	331	int ret;
	332
	333	if (!indio_dev->info->write_event_value)
	334	return -EINVAL;
	335
	336	ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
	337	if (ret)
	338	return ret;
	339	ret = indio_dev->info->write_event_value(indio_dev,
	340	this_attr->c, iio_ev_attr_type(this_attr),
	341	iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
	342	val, val2);
	343	if (ret < 0)
	344	return ret;
	345
	346	return len;
	347	}
	348
	349	static int iio_device_add_event(struct iio_dev *indio_dev,
	350	const struct iio_chan_spec *chan, unsigned int spec_index,
	351	enum iio_event_type type, enum iio_event_direction dir,
	352	enum iio_shared_by shared_by, const unsigned long *mask)
	353	{
	354	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	355	ssize_t (show)(struct device , struct device_attribute , char );
	356	ssize_t (store)(struct device , struct device_attribute *,
	357	const char *, size_t);
	358	unsigned int attrcount = 0;
	359	unsigned int i;
	360	char *postfix;
	361	int ret;
	362
	363	for_each_set_bit(i, mask, sizeof(mask)8) {
	364	if (i >= ARRAY_SIZE(iio_ev_info_text))
	365	return -EINVAL;
	366	if (dir != IIO_EV_DIR_NONE)
	367	postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
	368	iio_ev_type_text[type],
	369	iio_ev_dir_text[dir],
	370	iio_ev_info_text[i]);
	371	else
	372	postfix = kasprintf(GFP_KERNEL, "%s_%s",
	373	iio_ev_type_text[type],
	374	iio_ev_info_text[i]);
	375	if (postfix == NULL)
	376	return -ENOMEM;
	377
	378	if (i == IIO_EV_INFO_ENABLE) {
	379	show = iio_ev_state_show;
	380	store = iio_ev_state_store;
	381	} else {
	382	show = iio_ev_value_show;
	383	store = iio_ev_value_store;
	384	}
	385
	386	ret = __iio_add_chan_devattr(postfix, chan, show, store,
	387	(i << 16) \| spec_index, shared_by, &indio_dev->dev,
	388	&iio_dev_opaque->event_interface->dev_attr_list);
	389	kfree(postfix);
	390
	391	if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
	392	continue;
	393
	394	if (ret)
	395	return ret;
	396
	397	attrcount++;
	398	}
	399
	400	return attrcount;
	401	}
	402
	403	static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
	404	struct iio_chan_spec const *chan)
	405	{
	406	int ret = 0, i, attrcount = 0;
	407	enum iio_event_direction dir;
	408	enum iio_event_type type;
	409
	410	for (i = 0; i < chan->num_event_specs; i++) {
	411	type = chan->event_spec[i].type;
	412	dir = chan->event_spec[i].dir;
	413
	414	ret = iio_device_add_event(indio_dev, chan, i, type, dir,
	415	IIO_SEPARATE, &chan->event_spec[i].mask_separate);
	416	if (ret < 0)
	417	return ret;
	418	attrcount += ret;
	419
	420	ret = iio_device_add_event(indio_dev, chan, i, type, dir,
	421	IIO_SHARED_BY_TYPE,
	422	&chan->event_spec[i].mask_shared_by_type);
	423	if (ret < 0)
	424	return ret;
	425	attrcount += ret;
	426
	427	ret = iio_device_add_event(indio_dev, chan, i, type, dir,
	428	IIO_SHARED_BY_DIR,
	429	&chan->event_spec[i].mask_shared_by_dir);
	430	if (ret < 0)
	431	return ret;
	432	attrcount += ret;
	433
	434	ret = iio_device_add_event(indio_dev, chan, i, type, dir,
	435	IIO_SHARED_BY_ALL,
	436	&chan->event_spec[i].mask_shared_by_all);
	437	if (ret < 0)
	438	return ret;
	439	attrcount += ret;
	440	}
	441	ret = attrcount;
	442	return ret;
	443	}
	444
	445	static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
	446	{
	447	int j, ret, attrcount = 0;
	448
	449	/* Dynamically created from the channels array */
	450	for (j = 0; j < indio_dev->num_channels; j++) {
	451	ret = iio_device_add_event_sysfs(indio_dev,
	452	&indio_dev->channels[j]);
	453	if (ret < 0)
	454	return ret;
	455	attrcount += ret;
	456	}
	457	return attrcount;
	458	}
	459
	460	static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
	461	{
	462	int j;
	463
	464	for (j = 0; j < indio_dev->num_channels; j++) {
	465	if (indio_dev->channels[j].num_event_specs != 0)
	466	return true;
	467	}
	468	return false;
	469	}
	470
	471	static void iio_setup_ev_int(struct iio_event_interface *ev_int)
	472	{
	473	INIT_KFIFO(ev_int->det_events);
	474	init_waitqueue_head(&ev_int->wait);
	475	mutex_init(&ev_int->read_lock);
	476	}
	477
	478	static long iio_event_ioctl(struct iio_dev indio_dev, struct file filp,
	479	unsigned int cmd, unsigned long arg)
	480	{
	481	int __user ip = (int __user )arg;
	482	int fd;
	483
	484	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
	485	fd = iio_event_getfd(indio_dev);
	486	if (fd < 0)
	487	return fd;
	488	if (copy_to_user(ip, &fd, sizeof(fd)))
	489	return -EFAULT;
	490	return 0;
	491	}
	492
	493	return IIO_IOCTL_UNHANDLED;
	494	}
	495
	496	static const char *iio_event_group_name = "events";
	497	int iio_device_register_eventset(struct iio_dev *indio_dev)
	498	{
	499	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	500	struct iio_event_interface *ev_int;
	501	struct iio_dev_attr *p;
	502	int ret = 0, attrcount_orig = 0, attrcount, attrn;
	503	struct attribute **attr;
	504
	505	if (!(indio_dev->info->event_attrs \|\|
	506	iio_check_for_dynamic_events(indio_dev)))
	507	return 0;
	508
	509	ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
	510	if (ev_int == NULL)
	511	return -ENOMEM;
	512
	513	iio_dev_opaque->event_interface = ev_int;
	514
	515	INIT_LIST_HEAD(&ev_int->dev_attr_list);
	516
	517	iio_setup_ev_int(ev_int);
	518	if (indio_dev->info->event_attrs != NULL) {
	519	attr = indio_dev->info->event_attrs->attrs;
	520	while (*attr++ != NULL)
	521	attrcount_orig++;
	522	}
	523	attrcount = attrcount_orig;
	524	if (indio_dev->channels) {
	525	ret = __iio_add_event_config_attrs(indio_dev);
	526	if (ret < 0)
	527	goto error_free_setup_event_lines;
	528	attrcount += ret;
	529	}
	530
	531	ev_int->group.name = iio_event_group_name;
	532	ev_int->group.attrs = kcalloc(attrcount + 1,
	533	sizeof(ev_int->group.attrs[0]),
	534	GFP_KERNEL);
	535	if (ev_int->group.attrs == NULL) {
	536	ret = -ENOMEM;
	537	goto error_free_setup_event_lines;
	538	}
	539	if (indio_dev->info->event_attrs)
	540	memcpy(ev_int->group.attrs,
	541	indio_dev->info->event_attrs->attrs,
	542	sizeof(ev_int->group.attrs[0]) * attrcount_orig);
	543	attrn = attrcount_orig;
	544	/* Add all elements from the list. */
	545	list_for_each_entry(p, &ev_int->dev_attr_list, l)
	546	ev_int->group.attrs[attrn++] = &p->dev_attr.attr;
	547
	548	ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group);
	549	if (ret)
	550	goto error_free_setup_event_lines;
	551
	552	ev_int->ioctl_handler.ioctl = iio_event_ioctl;
	553	iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev,
	554	&ev_int->ioctl_handler);
	555
	556	return 0;
	557
	558	error_free_setup_event_lines:
	559	iio_free_chan_devattr_list(&ev_int->dev_attr_list);
	560	kfree(ev_int);
	561	iio_dev_opaque->event_interface = NULL;
	562	return ret;
	563	}
	564
	565	/**
	566	* iio_device_wakeup_eventset - Wakes up the event waitqueue
	567	* @indio_dev: The IIO device
	568	*
	569	* Wakes up the event waitqueue used for poll() and blocking read().
	570	* Should usually be called when the device is unregistered.
	571	*/
	572	void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
	573	{
	574	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	575
	576	if (iio_dev_opaque->event_interface == NULL)
	577	return;
	578	wake_up(&iio_dev_opaque->event_interface->wait);
	579	}
	580
	581	void iio_device_unregister_eventset(struct iio_dev *indio_dev)
	582	{
	583	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
	584	struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
	585
	586	if (ev_int == NULL)
	587	return;
	588
	589	iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler);
	590	iio_free_chan_devattr_list(&ev_int->dev_attr_list);
	591	kfree(ev_int->group.attrs);
	592	kfree(ev_int);
	593	iio_dev_opaque->event_interface = NULL;
	594	}