In the IRQ handler, the GPIO's state is read to verify the direction of
the edge that triggered the interruption before generating the PPS event.
If a pulse is too short, the GPIO line can reach back its original state
before this verification and the PPS event is lost.
This check is needed when info->capture_clear is set because it needs
interruptions on both rising and falling edges. When info->capture_clear
is not set, interruption is triggered by one edge only so this check can
be omitted.
Bypass the edge's direction verification when info->capture_clear is not
set.
Signed-off-by: Bastien Curutchet <[email protected]>
---
Change log v1 -> v2:
* Modifiy the way the bypass is done to avoid code duplication
v1: https://lore.kernel.org/all/[email protected]/
drivers/pps/clients/pps-gpio.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 2f4b11b4dfcd..e30bf1c84ea0 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -52,7 +52,9 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
info = data;
- rising_edge = gpiod_get_value(info->gpio_pin);
+ /* Small trick to bypass the check on edge's direction when capture_clear is unset */
+ rising_edge = info->capture_clear ?
+ gpiod_get_value(info->gpio_pin) : !info->assert_falling_edge;
if ((rising_edge && !info->assert_falling_edge) ||
(!rising_edge && info->assert_falling_edge))
pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
--
2.44.0