RE: [PATCH v8 0/9] Goodix touchscreen enhancements

[Tirdea, Irina]

> -----Original Message-----
> From: linux-input-owner@xxxxxxxxxxxxxxx [mailto:linux-input-owner@xxxxxxxxxxxxxxx] On Behalf Of Arnd Bergmann
> Sent: 08 October, 2015 17:32
> To: Tirdea, Irina
> Cc: Dmitry Torokhov; Bastien Nocera; Aleksei Mamlin; linux-input@xxxxxxxxxxxxxxx; Mark Rutland; Purdila, Octavian; linux-
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v8 0/9] Goodix touchscreen enhancements
> 
> On Thursday 08 October 2015 17:23:42 Irina Tirdea wrote:
> > Add several enhancements to the Goodix touchscreen driver.
> >
> > The new functionality is only available for devices that
> > declare named gpio pins for interrupt and reset in their
> > ACPI/DT configuration.
> >
> > Thanks,
> > Irina
> >
> > Changes in v8:
> >  - only allow new functionality for devices that declare named
> > gpios (using _DSD properties in ACPI or named DT properties)
> >
> >
> 
> Looks much cleaner this way, thanks!
> 
> One remaining question: how would you handle the case where
> the hardware doesn't support configuring the int-gpios line
> as output but you still want to use the named gpios?
> 

The only reason to use named gpios is to enable the new functionality
introduced by this patch set (mainly reset and power management).
You cannot use only one gpio either (e.g. only reset gpio but not the
interrupt gpio), you need both for this functionality to work.

If the hardware does not support using the interrupt gpio pin as output,
it should not declare the named int-gpio pin in ACPI. It is true that
we might later run into platforms that declare the int-gpio pin even if it
does not actually work (just like we now have the indexed gpio pins).
I could have added an additional property for this as you first suggested,
but if we can modify the ACPI to add it, we could simply remove the
named interrupt pin instead (that does not work anyway).

> I assume you have that case covered, but I don't see it immediately.
> 
> 	Arnd
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