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

From: Mark Brown
Date: Mon Sep 09 2013 - 12:19:40 EST


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).

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