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@xxxxxxxxxx>
Acked-by: Jonathan Cameron <jic23@xxxxxxxxxx>
---
drivers/staging/iio/industrialio-event.c | 23 ++++++++++++++++++++++-
1 files changed, 22 insertions(+), 1 deletions(-)
diff --git a/drivers/staging/iio/industrialio-event.c b/drivers/staging/iio/industrialio-event.c
index 14e505a..5fdf739 100644
--- a/drivers/staging/iio/industrialio-event.c
+++ b/drivers/staging/iio/industrialio-event.c
@@ -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>
@@ -56,7 +57,7 @@ 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);
@@ -64,6 +65,25 @@ 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,
@@ -117,6 +137,7 @@ 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,
--
1.7.8.3
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