Re: [PATCH 1/8] dt-bindings: HID: i2c-hid: elan: Introduce Elan eKTH8D18
From: Rob Herring
Date: Fri Mar 14 2025 - 19:43:09 EST
On Fri, Mar 14, 2025 at 02:58:36PM -0700, Doug Anderson wrote:
> Hi,
>
>
> On Wed, Mar 12, 2025 at 3:43 AM Chen-Yu Tsai <wenst@xxxxxxxxxxxx> wrote:
> >
> > The Elan eKTH8D18 touchscreen controller is an I2C HID device with a
> > longer boot-up time. Power sequence timing wise it is compatible with
> > the eKTH6A12NAY, with a power-on delay of at least 5ms, 20ms
> > out-of-reset for I2C ack response, and 150ms out-of-reset for I2C HID
> > enumeration. Enumeration and subsequent operation follows the I2C HID
> > standard. The eKTH6A12NAY requires longer times for both parts.
>
> Somehow the last sentence above confused me. Can it just be dropped?
> All you care about is that the new trackpad matches the timings for
> "eKTH6A12NAY". Not sure what you mean by "eKTH6A12NAY" needing
> "longer" timings.
>
>
> > Add a compatible string for it with the ekth6a12nay one as a fallback.
> >
> > Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> > ---
> > .../bindings/input/elan,ekth6915.yaml | 29 ++++++++++++++++---
> > 1 file changed, 25 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > index cb3e1801b0d3..81c391952ccc 100644
> > --- a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > +++ b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > @@ -4,14 +4,14 @@
> > $id: http://devicetree.org/schemas/input/elan,ekth6915.yaml#
> > $schema: http://devicetree.org/meta-schemas/core.yaml#
> >
> > -title: Elan eKTH6915 touchscreen controller
> > +title: Elan I2C-HID touchscreen controllers
> >
> > maintainers:
> > - Douglas Anderson <dianders@xxxxxxxxxxxx>
> >
> > description:
> > - Supports the Elan eKTH6915 touchscreen controller.
> > - This touchscreen controller uses the i2c-hid protocol with a reset GPIO.
> > + Supports the Elan eKTH6915 and other I2C-HID touchscreen controllers.
> > + These touchscreen controller use the i2c-hid protocol with a reset GPIO.
> >
> > allOf:
> > - $ref: /schemas/input/touchscreen/touchscreen.yaml#
> > @@ -23,12 +23,18 @@ properties:
> > - enum:
> > - elan,ekth5015m
> > - const: elan,ekth6915
> > + - items:
> > + - enum:
> > + - elan,ekth8d18
> > + - const: elan,ekth6a12nay
>
> The "enum" above is weird, but it matches what we did for
> "elan,ekth5015m" so I guess it's fine? I'd leave it up to bindings
> maintainers. I guess the assumption is that we might add additional
> touchscreens to the list...
Yes, but up to you all if that's a valid assumption.
>
>
> > reg:
> > - const: 0x10
> > + enum:
> > + - 0x10
> > + - 0x16
>
> Again happy to leave it to the bindings maintainers, but _maybe_ just
> drop the "reg" parts here and below. It doesn't really have to be part
> of the bindings.
I tend to agree. Sometimes we list I2C addresses as that is part of the
device whereas elsewhere it is not. I don't know that it's worth the
if/then schema in this case.
Rob