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staging:iio:events: Add poll support

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Add poll support to the event queue. This will allow us to check for pending
events in a application's event loop using poll() or similar. Since we already
have support for blocking reads adding poll support as well is trivial.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lars-Peter Clausen 2012-01-03 14:59:41 +01:00 committed by Greg Kroah-Hartman
parent 43ba1100af
commit e18045ed75
1 changed files with 22 additions and 1 deletions
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23
drivers/staging/iio/industrialio-event.c
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@ -15,6 +15,7 @@
#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>
@ -57,7 +58,7 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
copied = kfifo_put(&ev_int->det_events, &ev);
if (copied != 0)
wake_up_locked(&ev_int->wait);
wake_up_locked_poll(&ev_int->wait, POLLIN);
}
spin_unlock(&ev_int->wait.lock);
@ -65,6 +66,25 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
}
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,
@ -118,6 +138,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
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,