linux-kernel - Re: [PATCH v6 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866 backlight

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Message-ID: <Y8f7fbEJ0E6QQ0lZ@Gentoo>
Date:   Wed, 18 Jan 2023 22:00:29 +0800
From:   Jianhua Lu <lujianhua000@...il.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Lee Jones <lee@...nel.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>, Pavel Machek <pavel@....cz>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Helge Deller <deller@....de>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, linux-fbdev@...r.kernel.org
Subject: Re: [PATCH v6 1/2] dt-bindings: leds: backlight: Add Kinetic KTZ8866
 backlight

On Wed, Jan 18, 2023 at 02:40:00PM +0100, Krzysztof Kozlowski wrote:
> On 18/01/2023 14:10, Jianhua Lu wrote:
> > Add Kinetic KTZ8866 backlight binding documentation.
> > 
> > Signed-off-by: Jianhua Lu <lujianhua000@...il.com>
> > ---
> > Changes in v2:
> >   - Remove "items" between "compatible" and "const: kinetic,ktz8866"
> >   - Change "additionalProperties" to "unevaluatedProperties"
> > 
> > Changes in v3:
> >   - Add Krzysztof's R-b
> > 
> > Changes in v4:
> >   - Drop Krzysztof's R-b
> >   - Add some new properties
> > 
> > Changes in v5:
> >   - Add missing enum under property description.
> >   - Rename uncorrect properties.
> > 
> > Changes in v6:
> >   - Correct wrong property suffix and description.
> > 
> >  .../leds/backlight/kinetic,ktz8866.yaml       | 59 +++++++++++++++++++
> >  1 file changed, 59 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > new file mode 100644
> > index 000000000000..ca0deba14523
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/leds/backlight/kinetic,ktz8866.yaml
> > @@ -0,0 +1,59 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/leds/backlight/kinetic,ktz8866.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Kinetic Technologies KTZ8866 backlight
> > +
> > +maintainers:
> > +  - Jianhua Lu <lujianhua000@...il.com>
> > +
> > +description: |
> > +  The Kinetic Technologies KTZ8866 is a high efficiency 6-sinks led backlight
> > +  with dual lcd bias power.
> > +  https://www.kinet-ic.com/ktz8866/
> > +
> > +allOf:
> > +  - $ref: common.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: kinetic,ktz8866
> > +
> > +  current-num-sinks:
> > +    description: Number of LED current sinks.
> > +    enum: [1, 2, 3, 4, 5, 6]
> > +
> > +  current-ramping-time-ms:
> > +    description: LED current ramping time in milliseconds.
> > +    enum: [2, 4, 8, 16, 32, 64, 128, 192, 256, 320, 384, 448, 512, 576, 640]
> > +
> > +  led-ramping-time-ms:
> > +    description: |
> > +      LED on/off ramping time in milliseconds, note that the case 0 will be mapped
> > +      to 512μs because ktz8866 can't ramp faster than it.
> 
> Aren't you just missing supplies here and their ramp up time?
>
backlight ic supply bias power to panel, but downsteam devicetree adds power supplies node to panel node, 
so I'm not sure if need to add power supplies to backlight node.
> > +    enum: [0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384]
> > +
> > +  enable-lcd-bias:
> > +    description: Set if we want to output bias power supply for LCD.
> 
> Is it a generic property? I don't see any other users, so this looks
> device specific thus needs vendor prefix.
> 
> This applies to all of the properties. They might be generic or might
> not, I don't know the backlight hardware that much.
It surely is device specific, thanks.
> 
> > +    type: boolean
> > +
> > +required:
> > +  - compatible
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    backlight {
> > +        compatible = "kinetic,ktz8866";
> > +
> > +        pinctrl-names = "default";
> > +        pinctrl-0 = <&bl_en_default>;
> > +
> > +        current-num-sinks = <5>;
> > +        current-ramping-time-ms = <128>;
> > +        led-ramping-time-ms = <1>;
> > +        enable-lcd-bias;
> > +    };
> 
> Best regards,
> Krzysztof
>