[PATCH RFC 1/4] dt-bindings: input: touchscreen: Add Z2 controller bindings.

[Sasha Finkelstein]

On Mon, 27 Feb 2023 at 20:51, Rob Herring <robh at kernel.org> wrote:
>
> > +properties:
> > +  compatible:
> > +    const: apple,z2-touchscreen
>
> Is 'z2' anything other than a touchscreen? If not, '-touchscreen' is
> redundant. If so, then what else is there? You should be describing
> physical devices, not just a protocol for touchscreen.
>

This is a class of touchscreen controllers that talk the z2 protocol
over spi.

> > +                    touchscreen-size-y = <640>;
> > +                    apple,z2-device-name = "MacBookPro17,1 Touch Bar";
>
> Why do we need this string? If you want a human consumed label for
> some identification, we have a property for that purpose. It's called
> 'label'. But when there is only 1 instance, I don't really see the
> point.

I want a libinput-consumed label to distinguish between devices
using this protocol. It is used both for 'normal' touchscreens, and,
as is in this example a 'touchbar', which absolutely should not be
treated as a normal touchscreen, and needs special handling in
userspace.