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From:   Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
To:     Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Peter Geis <pgwipeout@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>
Cc:     devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: dts: rockchip: fix nEXTRST on SOQuartz
Date:   Fri, 21 Apr 2023 14:38:48 +0200
Message-ID: <12191318.O9o76ZdvQC@archbox>
In-Reply-To: <8914603.GXAFRqVoOG@phil>
References: <20230419171731.28641-1-frattaroli.nicolas@gmail.com>
 <8914603.GXAFRqVoOG@phil>
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Hello,

On Friday, 21 April 2023 13:58:58 CEST Heiko Stuebner wrote:
> Hi,
>=20
> Am Mittwoch, 19. April 2023, 19:17:31 CEST schrieb Nicolas Frattaroli:
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3566-soquartz.dtsi
> > b/arch/arm64/boot/dts/rockchip/rk3566-soquartz.dtsi index
> > ce7165d7f1a1..f589a4fdaccb 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3566-soquartz.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3566-soquartz.dtsi
> > @@ -65,6 +65,17 @@ led_work: led-work {
> >=20
> >  		};
> >  =09
> >  	};
> >=20
> > +	nextrst_pin: nextrst-pin-regulator {
> > +		compatible =3D "regulator-fixed";
> > +		enable-active-high;
> > +		gpio =3D <&gpio0 RK_PA5 GPIO_ACTIVE_HIGH>;
> > +		pinctrl-names =3D "default";
> > +		pinctrl-0 =3D <&nextrst_h>;
> > +		regulator-always-on;
> > +		regulator-boot-on;
> > +		regulator-name =3D "nextrst";
> > +	};
> > +
>=20
> I agree with the sentiment and of course the rationale of the change,
> but not necessarily with the implementation ;-) .
>=20
> Why is this done as a regulator?
>=20
> If you want the nextrst line to be high, you could just use a gpio-hog
> for the line instead of doing a (fake?-)regulator.

Simply put: because I didn't know gpio hogs were a thing. I'll send a V2
to correct this. Thanks for pointing it out!

>=20
> For example the px30-ringneck.dtsi does something similar:
>=20
> &gpio2 {
>         /*
>          * The Qseven BIOS_DISABLE signal on the PX30-=B5Q7 keeps the
> on-module * eMMC powered-down initially (in fact it keeps the reset signal
> * asserted). BIOS_DISABLE_OVERRIDE pin allows to re-enable eMMC after * t=
he
> SPL has been booted from SD Card.
>          */
>         bios-disable-override-hog {
>                 gpios =3D <RK_PB5 GPIO_ACTIVE_LOW>;
>                 output-high;
>                 line-name =3D "bios_disable_override";
>                 gpio-hog;
>         };
> ...
> };
>=20
>=20
> Thanks
> Heiko

Kind regards,
Nicolas Frattaroli