[PATCH v9 7/7] arm64: dts: mediatek: mt8173-elm-hana: Mark touchscreens and trackpads as fail

[Chen-Yu Tsai]

On Fri, Oct 18, 2024 at 5:16 AM Doug Anderson <dianders at chromium.org> wrote:
>
> Hi,
>
> On Thu, Oct 17, 2024 at 2:42 AM Chen-Yu Tsai <wenst at chromium.org> wrote:
> >
> > Instead of having them all available, mark them all as "fail-needs-probe"
> > and have the implementation try to probe which one is present.
> >
> > Also remove the shared resource workaround by moving the pinctrl entry
> > for the trackpad interrupt line back into the individual trackpad nodes.
>
> It could be worth noting in the description that it's a really bad
> idea to pick this patch if you don't also have the patch
> ("platform/chrome: Introduce device tree hardware prober").

I found that there's a stable tag one can add to reject AUTOSEL.
Sounds like the perfect thing to add here.

> > @@ -35,6 +37,7 @@ touchscreen at 40 {
> >                 hid-descr-addr = <0x0001>;
> >                 interrupt-parent = <&pio>;
> >                 interrupts = <88 IRQ_TYPE_LEVEL_LOW>;
> > +               status = "fail-needs-probe";
>
> It's a little weird that there's no pinctrl definition for the
> touchscreens but there is one for the trackpad, but that predates your
> patch and is unlikely to be a big deal.

To be honest I'm in favor of getting rid of pinctrl settings that
do nothing more than mux in a GPIO, as mentioned in my talk at ELCE.
Such settings are already implied by the interrupts or gpios properties.
The fact that the OS doesn't enforce exclusiveness between the
subsystems is not something the DT should deal with.

> >         };
> >  };
> >
> > @@ -47,6 +50,8 @@ &i2c4 {
> >         trackpad2: trackpad at 2c {
> >                 compatible = "hid-over-i2c";
> >                 interrupts-extended = <&pio 117 IRQ_TYPE_LEVEL_LOW>;
> > +               pinctrl-names = "default";
> > +               pinctrl-0 = <&trackpad_irq>;
> >                 reg = <0x2c>;
>
> I should have noticed before, but officially the order above is
> slightly off. According to:
>
> https://docs.kernel.org/devicetree/bindings/dts-coding-style.html
>
> The "reg" property should be higher (right after compatible). It's not
> a new problem with your patch but since you're inserting a new
> property you might as well match the new dts style.

The entry in mt8173-elm.dtsi is also in the wrong order. I think I'll
do a patch later on to just fix it up if it's a major eyesore.

Angelo what do you think?

> In any case, nothing is a huge deal.
>
> Reviewed-by: Douglas Anderson <dianders at chromium.org>

Thanks!
ChenYu