Messages in this thread | | | Date | Mon, 11 Nov 2013 19:28:37 +0100 | From | Gerlando Falauto <> | Subject | Re: [PATCH v3] gpio: interrupt consistency check for OF GPIO IRQs |
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Hi everyone,
[jumping in on an old discussion]
On 09/09/2013 06:19 PM, 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).
I actually came across this thread while looking for an answer to the following (apparently trivial) question:
If you were to write a new driver & binding, what would be, in general, the recommended DT binding for a cascade interrupt controller (or any other peripheral, for that matter), which is connected through a GPIO (to be used as IRQ)?
a) Through gpios = <&gpio0 N> b) through interrupt-parent = <&gpio0> & interrupts <N IRQ_TYPE_LEVEL_LOW>, or c) both?
Thanks! Gerlando
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