When the interrupt line is shared with other devices, the IRQ must be level-triggered, as only one device can trigger a falling edge. To support this, try to acquire the IRQ with IRQF_TRIGGER_LOW|IRQF_SHARED first. Interrupt controllers that lack support for level-triggers will return an error, in which case the driver will now retry the acqusition with IRQF_TRIGGER_FALLING, which was also the default before. Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx> --- drivers/tty/serial/sc16is7xx.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index cebc0cf9c30e..7e2360f8e393 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1313,7 +1313,19 @@ static int sc16is7xx_probe(struct device *dev, s->p[u].irda_mode = true; } - /* Setup interrupt */ + /* + * Setup interrupt. We first try to acquire the IRQ line as level IRQ. + * If that succeeds, we can allow sharing the interrupt as well. + * In case the interrupt controller doesn't support that, we fall + * back to a non-shared falling-edge trigger. + */ + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, + IRQF_TRIGGER_LOW | IRQF_SHARED | + IRQF_ONESHOT, + dev_name(dev), s); + if (!ret) + return 0; + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, dev_name(dev), s); -- 2.26.2
