From: Alexander GQ Gerasiov <g...@cs.msu.su>
On some devices interrupt may be invoked by parasitic assert event produced
while switching from high to low. Such interrupt should be ignored.
Signed-off-by: Alexander GQ Gerasiov <g...@cs.msu.su>
---
drivers/pps/clients/pps_parport.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/pps/clients/pps_parport.c
b/drivers/pps/clients/pps_parport.c
index 37094b0..39c1fea 100644
--- a/drivers/pps/clients/pps_parport.c
+++ b/drivers/pps/clients/pps_parport.c
@@ -69,6 +69,8 @@ static void parport_irq(void *handle)
struct pps_event_time ts_assert, ts_clear;
struct pps_client_pp *dev = handle;
struct parport *port = dev->pardev->port;
+ static struct pps_event_time prev;
+ static struct timespec64 ts_delta;
unsigned int i;
unsigned long flags;
@@ -95,9 +97,14 @@ static void parport_irq(void *handle)
/* check the signal (no signal means the pulse is lost this time) */
if (!signal_is_set(port)) {
local_irq_restore(flags);
- dev_err(dev->pps->dev, "lost the signal\n");
+ ts_delta = timespec64_sub(ts_assert.ts_real, prev.ts_real);
+ /* do not print error message in case interrupt handler is
+ * invoked by parasitic assert event */
+ if (timespec64_to_ns(&ts_delta) > (NSEC_PER_SEC / 2))
+ dev_err(dev->pps->dev, "lost the signal\n");
goto out_none;
}
+ prev = ts_assert;
/* poll the port until the signal is unset */
for (i = dev->cw; i; i--)
--
2.1.4
