Re: [PATCH v3] gpio: interrupt consistency check for OF GPIO IRQs

Lars Poeschel
2013-09-10T08:47:55Z

On Tuesday 10 September 2013 17:19:24, Mark Brown wrote:
> On Wed, Sep 04, 2013 at 02:16:36PM -0600, Stephen Warren wrote:
> > On 09/04/2013 03:05 AM, Lars Poeschel wrote:
> > > The driver that tries to use the GPIO requested by this patch before HAS
> > > to
> > > fail. This is exactly the intention of this patch. We don't want the
> > > GPIO to be requested any more, if it is used as an interrupt pin.
> >
> > That will break existing drivers. There are drivers that request the
> > same GPIO and IRQ. IIRC, the SDHCI CD (Card Detect) GPIO is requested
> > that way.
>
> Yes, plus input devices and audio jack detection among others. This
> pattern is very common if the GPIO is actually being used as a GPIO, an
> edge triggered interrupt is used to flag when something happens and the
> state is determined by reading the GPIO state (often with some
> debounce).

And I say it again for those coming into the discussion late, like it has been
said many many times before: This patch does not break any of this drivers.
They simply request their GPIO from DT and turn it into an irq using
gpio_to_irq, request that irq on their behalf and use it as GPIO and IRQ in
parallel. At least this is not a problem.