diff options
| author |   Daniel Mack <daniel@zonque.org> | 2020-05-21 11:11:51 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-22 11:06:14 +0200 |
| commit | 2d12fc792cdd43da8502de4a425a98e520b1c302 (patch) | |
| tree | ef4637d6d21417e3400834e4382bd43ab811d6ba /drivers/tty | |
| parent | sc16is7xx: Use threaded IRQ (diff) | |
| download | wireguard-linux-2d12fc792cdd43da8502de4a425a98e520b1c302.tar.xz wireguard-linux-2d12fc792cdd43da8502de4a425a98e520b1c302.zip | |
sc16is7xx: Allow sharing the IRQ line
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@zonque.org>
Link: https://lore.kernel.org/r/20200521091152.404404-6-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/sc16is7xx.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 3908a2154b7f..7d98367d6e83 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1293,7 +1293,19 @@ static int sc16is7xx_probe(struct device *dev, sc16is7xx_power(&s->p[i].port, 0); } - /* 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); |