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/* Industrial I/O event handling
*
* 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.
*
* 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 "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
*/
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;
};
int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
{
struct iio_event_interface *ev_int = indio_dev->event_interface;
struct iio_event_data ev;
int copied;
/* Does anyone care? */
spin_lock(&ev_int->wait.lock);
if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
ev.id = ev_code;
ev.timestamp = timestamp;
copied = kfifo_put(&ev_int->det_events, &ev);
if (copied != 0)
wake_up_locked_poll(&ev_int->wait, POLLIN);
}
spin_unlock(&ev_int->wait.lock);
return 0;
}
EXPORT_SYMBOL(iio_push_event);
/**
* iio_event_poll() - poll the event queue to find out if it has data
*/
static unsigned int iio_event_poll(struct file *filep,
struct poll_table_struct *wait)
{
struct iio_event_interface *ev_int = filep->private_data;
unsigned int events = 0;
poll_wait(filep, &ev_int->wait, wait);
spin_lock(&ev_int->wait.lock);
if (!kfifo_is_empty(&ev_int->det_events))
events = POLLIN | POLLRDNORM;
spin_unlock(&ev_int->wait.lock);
return events;
}
static ssize_t iio_event_chrdev_read(struct file *filep,
char __user *buf,
size_t count,
loff_t *f_ps)
{
struct iio_event_interface *ev_int = filep->private_data;
unsigned int copied;
int ret;
if (count < sizeof(struct iio_event_data))
return -EINVAL;
spin_lock(&ev_int->wait.lock);
if (kfifo_is_empty(&ev_int->det_events)) {
if (filep->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto error_unlock;
}
/* Blocking on device; waiting for something to be there */
ret = wait_event_interruptible_locked(ev_int->wait,
!kfifo_is_empty(&ev_int->det_events));
if (ret)
goto error_unlock;
/* Single access device so no one else can get the data */
}
ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
error_unlock:
spin_unlock(&ev_int->wait.lock);
return ret ? ret : copied;
}
static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
{
struct iio_event_interface *ev_int = filep->private_data;
spin_lock(&ev_int->wait.lock);
__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
/*
* In order to maintain a clean state for reopening,
* clear out any awaiting events. The mask will prevent
* any new __iio_push_event calls running.
*/
kfifo_reset_out(&ev_int->det_events);
spin_unlock(&ev_int->wait.lock);
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,
};
int iio_event_getfd(struct iio_dev *indio_dev)
{
struct iio_event_interface *ev_int = indio_dev->event_interface;
int fd;
if (ev_int == NULL)
return -ENODEV;
spin_lock(&ev_int->wait.lock);
if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
spin_unlock(&ev_int->wait.lock);
return -EBUSY;
}
spin_unlock(&ev_int->wait.lock);
fd = anon_inode_getfd("iio:event",
&iio_event_chrdev_fileops, ev_int, O_RDONLY);
if (fd < 0) {
spin_lock(&ev_int->wait.lock);
__clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
spin_unlock(&ev_int->wait.lock);
}
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",
};
static const char * const iio_ev_dir_text[] = {
[IIO_EV_DIR_EITHER] = "either",
[IIO_EV_DIR_RISING] = "rising",
[IIO_EV_DIR_FALLING] = "falling"
};
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->address,
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 = indio_dev->info->read_event_config(indio_dev,
this_attr->address);
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, ret;
ret = indio_dev->info->read_event_value(indio_dev,
this_attr->address, &val);
if (ret < 0)
return ret;
return sprintf(buf, "%d\n", val);
}
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);
unsigned long val;
int ret;
if (!indio_dev->info->write_event_value)
return -EINVAL;
ret = strict_strtoul(buf, 10, &val);
if (ret)
return ret;
ret =
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