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pps: clients: gpio: Bypass edge's direction check when not needed

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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 <bastien.curutchet@bootlin.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20250108153012.514925-1-bastien.curutchet@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bastien Curutchet 2025-01-08 16:30:12 +01:00 committed by Greg Kroah-Hartman
parent 6d2478a103
commit a01f6287c2
1 changed files with 5 additions and 1 deletions
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6
drivers/pps/clients/pps-gpio.c
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@ -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;
}