Can I register an IRQ with any GPIO line?
Are there specific GPIO pins that are set up to be an IRQ that I should be
I am a hardware guy so I'm not very familiar with the kernel.
I am trying to find a gpio line that I can connect to a supervisor chip that
will tell the gumstix to shutdown when the board is losing power.
I was looking at the post below, but couldn't figure out if I should be
using a specific gpio pin as an interrupt or if I can just choose any line I
want that isn't being used.
Thanks for your help,
On Thu, Sep 16, 2010 at 5:46 PM, Derek Nielson <dereknielson@...> wrote:
> Can I register an IRQ with any GPIO line?
> Are there specific GPIO pins that are set up to be an IRQ that I should be
I think all GPIO's can be used as IRQs. There may be some exceptions,
but I'm not aware of any.
The convention in the link you provided looks correct -- generally you
have to translate the GPIO to an IRQ, then request that IRQ.
irq = gpio_to_irq(gpio);
request_irq(irq, handler, IRQF_TRIGGER_FALLING,
> I think all GPIO's can be used as IRQs. There may be some exceptions,
> but I'm not aware of any.
A minor follow up on this one for the future. All GPIOs on OMAP can be used
for interrupts. One minor note is, that the GPIOs 0 to 31 can wake up the
system even from the lowest power-state (wakeup clock/domain), while the
others have to have the peripheral clock/domain running. For most practical
use this isn't a real problem, but in case you really care about power
saving this might be worth considering. More info to be found in the GPIO
chapter of the OMAP3 TRM (spruf98)...
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