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Date:   Tue, 6 Jun 2023 11:47:48 -0700
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     cong yang <yangcong5@huaqin.corp-partner.google.com>
Cc:     Conor Dooley <conor@kernel.org>, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        jikos@kernel.org, benjamin.tissoires@redhat.com,
        dianders@chromium.org, hsinyi@google.com,
        linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: input: touchscreen: Add ilitek 9882T
 touchscreen chip
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On Tue, Jun 06, 2023 at 10:06:05AM +0800, cong yang wrote:
> Hi,Conor,
> 
> On Mon, Jun 5, 2023 at 6:20 PM Conor Dooley <conor@kernel.org> wrote:
> >
> > Hey Cong Yang,
> >
> > On Mon, Jun 05, 2023 at 02:05:23PM +0800, Cong Yang wrote:
> > > Add an ilitek touch screen chip ili9882t.
> >
> > Could you add a comment here mentioning the relationship between these
> > chips?
> 
> Okay, I will add in V3 version.
> 
> > On Mon, Jun 05, 2023 at 02:05:23PM +0800, Cong Yang wrote:
> >
> > > Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
> > > ---
> > >  .../bindings/input/elan,ekth6915.yaml         | 23 ++++++++++++++++---
> > >  1 file changed, 20 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > > index 05e6f2df604c..f0e7ffdce605 100644
> > > --- a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > > +++ b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
> > > @@ -15,11 +15,14 @@ description:
> > >
> > >  properties:
> > >    compatible:
> > > -    items:
> > > -      - const: elan,ekth6915
> > > +    enum:
> > > +      - elan,ekth6915
> > > +      - ilitek,ili9882t
> > >
> > >    reg:
> > > -    const: 0x10
> > > +    enum:
> > > +      - 0x10
> > > +      - 0x41
> >
> > Is 0x10 only valid for the elan,ekth6915 & 0x41 for the ilitek one?
> > If so, please add some enforcement of the values based on the
> > compatible.
> 
> I don't think 0x10 is the only address for ekth6915,(nor is 0x41 the
> only address for ili9882t). It depends on the hardware design.

Only a handful of controllers allow switching between addresses, and
if they do they typically have a "main" and an "alternate" one, and not
something completely customizable. I do not believe Elan offers ways to
program different address, do they?

Thanks.

-- 
Dmitry