Re: [PATCH v2] gpio: interrupt consistency check for OF GPIO IRQs

Lars Poeschel
2013-08-23T09:51:26Z

On Thursday 22 August 2013 at 22:53:09, Stephen Warren wrote:
> On 08/21/2013 05:27 PM, Linus Walleij wrote:
> > On Thu, Aug 22, 2013 at 1:10 AM, Stephen Warren <swarren@wwwdotorg.org>
wrote:
> >>> On Wednesday 21 of August 2013 15:38:54 Lars Poeschel wrote:
> >>>> To solve this dilemma, perform an interrupt consistency check
> >>>> when adding a GPIO chip: if the chip is both gpio-controller and
> >>>> interrupt-controller, walk all children of the device tree,
> >>
> >> It seems a little odd to solve this only for DT. What about the
> >> non-DT case?
> >
> > DT is the hardware configuration system that lets you request
> > the same resource in two ways, i.e. it allows one and the same
> > node to be both gpio-controller and interrupt-controller, and
> > start handing out the same line as both GPIO and IRQ
> > independently.
>
> Huh? What stops systems using board files and platform data from having
> this issue?

I am not 100% sure, Linus knows better.
I think nothing stops them from having this issue, but board files are
gentle and request the GPIO before doing gpio_to_irq, because they know
that they are using a gpio based interrupt.

You can read the whole story here:
http://www.mail-archive.com/linux-omap@vger.kernel.org/msg91405.html
Things get interesting after the first mail from Alexander Holler, who is
the first having a problem with the patch in the link.