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Subject[PATCH] pps : add non blocking option to PPS_FETCH ioctl.
Date
The PPS_FETCH ioctl is blocking still the reception of a PPS
event. But, in some case, one may immediately need the last event
date. This patch allow to get the result of PPS_FETCH if the device
has the O_NONBLOCK flag set.

Signed-off-by: Paul Chavent <paul.chavent@onera.fr>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
---
drivers/pps/pps.c | 57 +++++++++++++++++++++++++++++--------------------------
1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 2f07cd6..983f50c 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -152,35 +152,38 @@ static long pps_cdev_ioctl(struct file *file,
if (err)
return -EFAULT;

- ev = pps->last_ev;
-
- /* Manage the timeout */
- if (fdata.timeout.flags & PPS_TIME_INVALID)
- err = wait_event_interruptible(pps->queue,
- ev != pps->last_ev);
- else {
- unsigned long ticks;
-
- dev_dbg(pps->dev, "timeout %lld.%09d\n",
- (long long) fdata.timeout.sec,
- fdata.timeout.nsec);
- ticks = fdata.timeout.sec * HZ;
- ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
-
- if (ticks != 0) {
- err = wait_event_interruptible_timeout(
- pps->queue,
- ev != pps->last_ev,
- ticks);
- if (err == 0)
- return -ETIMEDOUT;
+ if (!(file->f_flags & O_NONBLOCK)) {
+ ev = pps->last_ev;
+
+ /* Manage the timeout */
+ if (fdata.timeout.flags & PPS_TIME_INVALID)
+ err = wait_event_interruptible(pps->queue,
+ ev != pps->last_ev);
+ else {
+ unsigned long ticks;
+
+ dev_dbg(pps->dev, "timeout %lld.%09d\n",
+ (long long) fdata.timeout.sec,
+ fdata.timeout.nsec);
+ ticks = fdata.timeout.sec * HZ;
+ ticks += fdata.timeout.nsec /
+ (NSEC_PER_SEC / HZ);
+
+ if (ticks != 0) {
+ err = wait_event_interruptible_timeout(
+ pps->queue,
+ ev != pps->last_ev,
+ ticks);
+ if (err == 0)
+ return -ETIMEDOUT;
+ }
}
- }

- /* Check for pending signals */
- if (err == -ERESTARTSYS) {
- dev_dbg(pps->dev, "pending signal caught\n");
- return -EINTR;
+ /* Check for pending signals */
+ if (err == -ERESTARTSYS) {
+ dev_dbg(pps->dev, "pending signal caught\n");
+ return -EINTR;
+ }
}

/* Return the fetched timestamp */
--
1.7.12.1


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