6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bastien Curutchet <redacted>
[ Upstream commit a01f6287c244f35eeec11ca932d09061181eed8c ]
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.
Add a warning if irq_handler is left without triggering any PPS event.
Bypass the edge's direction verification when info->capture_clear is not
set.
Signed-off-by: Bastien Curutchet <redacted>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20250108153012.514925-1-bastien.curutchet@bootlin.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: b899e0279f90 ("pps-gpio: remove dead capture_clear code")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pps/clients/pps-gpio.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 41e1fdbcda165..dbe598d092099 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);
@@ -60,6 +62,8 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
((rising_edge && info->assert_falling_edge) ||
(!rising_edge && !info->assert_falling_edge)))
pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
+ else
+ dev_warn_ratelimited(&info->pps->dev, "IRQ did not trigger any PPS event\n");
return IRQ_HANDLED;
}
--
2.53.0