Re: [PATCH V2 1/3] dt: palmas: support IRQ inversion at the board level

[Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Thu, Feb 27, 2014 at 02:35:42PM -0700, Stephen Warren wrote:
> On 02/27/2014 02:02 PM, Graeme Gregory wrote:

> >> +- ti,irq-externally-inverted : If missing, the polarity of the Palmas IRQ
> >> +  output should be set to the opposite of the polarity indicated by the IRQ
> >> +  specifier in the interrupts property. If absent, the polarity should be
> >> +  configured to match. This allows the representation of an inverter between
> >> +  the Palmas IRQ output and the interrupt parent's IRQ input.

> > This has got to be the wrong way to do things, all this leads to is every
> > device doing this property in its own way and having totally inconsistent
> > properties all meaning the same thing.

> > If there is some other hardware inverting lines then there should be
> > a generic binding for this in DT. This is not describing the palmas hardware
> > but some external object to the palmas.

> I'd be fine with removing the "ti," vendor prefix from the property
> name, and promoting it to be a cross-device standard.

> I'm not sure that many devices will need this though; most don't have
> configurable output polarity. Still, I guess that shouldn't stop us from
> creating standards for the cases where it is needed.

It's really common for PMICs and CODECs to be able to set any interrupt
polarity at least.

> If the DT reviewers can ack the concept, I'm happy to respin the patch
> with the more generic property name.

I'm not sure that renaming the property really deals with the concerns
though since drivers still all need to manually add support for this,
shouldn't there be an interrupt controller described in the DT which
just chains on to the parent with the polarity inverted to do the
impedence match?

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