Re: [PATCH v2] Input: tsc2007 - use GPIO descriptor

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Tue, Aug 27, 2019 at 09:42:46AM +0200, Linus Walleij wrote:
> On Tue, Aug 27, 2019 at 12:00 AM Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> 
> > >  Optional properties:
> > >  - gpios: the interrupt gpio the chip is connected to (trough the penirq pin).
> > > -  The penirq pin goes to low when the panel is touched.
> > > +  The penirq pin goes to low when the panel is touched, so make sure to tag
> > > +  the GPIO line with GPIO_ACTIVE_LOW.
> >
> > I think this is too strong. I am sure that one can come up with a way to
> > connect the attention signal though polarity inverter and then one would
> > have to specify GPIO_ACTIVE_HIGH in the DT.
> 
> Yeah this is something that has been discussed recently as
> Harish is suggesting to add an actual inverter to the device
> tree model. As the description of reality in the device tree is
> incomplete, these flags, which should nominally be consumer
> flags and indicate the behavior of the consumer, becomes
> a panacea for solving shortcomings in the device tree model.
> 
> I am in favor of introducing explicit inverters in device tree,
> as it makes the descriptions more consistent: e.g. regulators
> are consumer oriented, they even model rails to make things
> very clear on where a voltage applies, whereas GPIO polarity
> is defined as "trial-and-error until whatever makes the system
> run" more or less.
> 
> > Can we say:
> >
> > The penirq pin goes to low when the panel is touched, so GPIO line
> > should normally be tagged with GPIO_ACTIVE_LOW.
> 
> Sure, this is not the place for hashing out DT design issues,
> can you fix when applying or should I send a new version?

I can fix it up on my side, once I hear from DY folks that they are OK
with existing DTS changes.

Thanks.

-- 
Dmitry