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References: <20211121235808.10167-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
In-Reply-To: <20211121235808.10167-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 23 Nov 2021 15:44:38 +0100
Message-ID: <CAMuHMdXvehNc5yRxO4cS=n_ZaDWCKq2iaKhs+b3uj2beYsdWVg@mail.gmail.com>
Subject: Re: [PATCH] arm64: dts: hihope-rzg2-ex-lvds: Add power-supply and
 enable-gpios to backlight node
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc:     Magnus Damm <magnus.damm@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Prabhakar <prabhakar.csengg@gmail.com>,
        Biju Das <biju.das.jz@bp.renesas.com>
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Hi Prabhakar,

On Mon, Nov 22, 2021 at 12:58 AM Lad Prabhakar
<prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> This patch adds missing power-supply and enable-gpios property to
> backlight node. This fixes the warning "pwm-backlight backlight:
> backlight supply power not found, using dummy regulator".
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Thanks for your patch!

> --- a/arch/arm64/boot/dts/renesas/hihope-rzg2-ex-lvds.dtsi
> +++ b/arch/arm64/boot/dts/renesas/hihope-rzg2-ex-lvds.dtsi
> @@ -12,6 +12,17 @@
>
>                 brightness-levels = <0 2 8 16 32 64 128 255>;
>                 default-brightness-level = <6>;
> +               power-supply = <&reg_12v>;
> +               enable-gpios = <&gpio6 7 GPIO_ACTIVE_HIGH>;

According to the schematics (up to Rev. 4.00), GP6_07 is not connected?

> +       };
> +
> +       reg_12v: regulator2 {

Using "regulatorN" as a node name is error-prone, and may lead to
accidental clashes. Please use a more appropriate name.

> +               compatible = "regulator-fixed";
> +               regulator-name = "fixed-12V";
> +               regulator-min-microvolt = <12000000>;
> +               regulator-max-microvolt = <12000000>;

Hmm, the AT1316A is a constant-current source, not a constant-voltage
source? The -02 variant has a 0.2V Low Reference Voltage. Combined
with the 1.1Ω resistor, that should give 181818 microamp.

> +               regulator-boot-on;
> +               regulator-always-on;
>         };
>  };

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds