linux-kernel - Re: [PATCH v2 02/18] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays

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Message-ID: <CAL_JsqLbxkbyK0c0mUadxu0OQtQxezY4DNSLkBZWpETwuG_70w@mail.gmail.com>
Date:   Thu, 15 Jul 2021 08:32:07 -0600
From:   Rob Herring <robh@...nel.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Robin van der Gracht <robin@...tonic.nl>,
        Miguel Ojeda <ojeda@...nel.org>,
        Paul Burton <paulburton@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pavel Machek <pavel@....cz>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        linux-leds <linux-leds@...r.kernel.org>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 02/18] dt-bindings: auxdisplay: ht16k33: Document
 Adafruit segment displays

On Thu, Jul 15, 2021 at 1:12 AM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> Hi Rob,
>
> Note that you commented on v2, while I posted v3 yesterday.
>
> On Wed, Jul 14, 2021 at 10:36 PM Rob Herring <robh@...nel.org> wrote:
> > On Fri, Jun 25, 2021 at 02:58:46PM +0200, Geert Uytterhoeven wrote:
> > > The Holtek HT16K33 LED controller is not only used for driving
> > > dot-matrix displays, but also for driving segment displays.
> > >
> > > Document compatible values for the Adafruit 7-segment[1] and
> > > 14-segment[2] FeatherWing expansion boards with red displays.  According
> > > to the schematics, all other Adafruit 7-segment and 14-segment display
> > > backpack and FeatherWing expansion boards (including bare boards and
> > > boards fitted with displays) are compatible with these two boards.
> > > Add a "color" property to support the different color variants.
> > >
> > > [1] https://www.adafruit.com/product/3108
> > > [2] https://www.adafruit.com/product/3130
> > >
> > > Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
>
> > > --- a/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
> > > +++ b/Documentation/devicetree/bindings/auxdisplay/holtek,ht16k33.yaml
> > > @@ -14,14 +14,23 @@ allOf:
> > >
> > >  properties:
> > >    compatible:
> > > -    const: holtek,ht16k33
> > > +    oneOf:
> > > +      - items:
> > > +          - const: adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing Display (Red)
> > > +          - const: holtek,ht16k33
> > > +
> > > +      - items:
> > > +          - const: adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing Display (Red)
> > > +          - const: holtek,ht16k33
> >
> > These 2 entries can be combined.
>
> Right.  This split dates back from when I considered adding all
> possible compatible values.  It can indeed be simplified to:
>
>           - enum:
>               - adafruit,3108  # 0.56" 4-Digit 7-Segment FeatherWing
> Display (Red)
>               - adafruit,3130  # 0.54" Quad Alphanumeric FeatherWing
> Display (Red)
>           - const: holtek,ht16k33
>
> > Or make the comment a 'description'.
>
> What do you mean?

Adding this:

description: '0.54" Quad Alphanumeric FeatherWing Display (Red)'


> > > +
> > > +      - const: holtek,ht16k33     # Generic 16*8 LED controller with dot-matrix display
>
> > >  required:
> > >    - compatible
> > >    - reg
> > > -  - refresh-rate-hz
> > > +
> > > +if:
> > > +  properties:
> > > +    compatible:
> > > +      const: holtek,ht16k33
> >
> > Isn't this always true?
>
> It is false if there is more than one compatible value.

Ah, yes.

Rob