>From 370fca528140f879957a1b717fe9c13855d5c7f7 Mon Sep 17 00:00:00 2001 From: Paul Chavent Date: Wed, 4 Sep 2013 10:09:43 +0200 Subject: [PATCH] pps : add non blocking option to PPS_FETCH ioctl (v2). This new version add a commit message with more details. The PPS_FETCH ioctl is blocking still the reception of a pps event. But, in some case, one may need the last event date immediately. This patch allow to get the result of PPS_FETCH if the device has the O_NONBLOCK flag set. Signed-off-by: Paul Chavent --- 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