linux-kernel - Re: [PATCH v2] ARM: dts: sun8i-r40: remove unused GPIO regulator

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Message-ID: <e61c927a4dfe909f4ede4a07dffd9dcd762875be.camel@icenowy.me>
Date: Sat, 14 Dec 2024 15:13:23 +0800
From: Icenowy Zheng <uwu@...nowy.me>
To: Andre Przywara <andre.przywara@....com>, Hermann.Lauer@...-heidelberg.de
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
  Conor Dooley <conor+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>, Jernej
 Skrabec <jernej.skrabec@...il.com>,  Samuel Holland <samuel@...lland.org>,
 devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] ARM: dts: sun8i-r40: remove unused GPIO regulator

在 2024-12-14星期六的 01:16 +0000，Andre Przywara写道：
> On Fri, 13 Dec 2024 20:54:33 +0100
> Hermann.Lauer@...-heidelberg.de wrote:
> 
> Hi,
> 
> CC:ing Icenowy, who added the regulator originally, with commit
> 0ca12c1ee43c ("ARM: sun8i: r40: add 5V regulator for Banana Pi M2
> Ultra").
> 
> Icenowy: can you clarify what "newer" version this was referring to
> in
> that commit message? That commit in itself doesn't seem to do
> anything,
> as the regulator isn't referenced, and it's not always-on. It's only
> later when the USB nodes were added that it got used?
> So was PH23 really necessary? As Hermann reports, setting PH23 on a
> v1.1
> makes it reboot.

I am not sure, the schematics I have here (which says V1.0) have PH23
as NC... Well, the M2 Berry schematics have PH23 as 5V EN, maybe I
messed up M2U and M2B when developing?

Sorry but I think the data retention situation of my memory looks bad
here, maybe it needs a shorter refresh interval ;-)

> 
> > Subject: [PATCH v2] ARM: dts: sun8i-r40: remove unused GPIO
> > regulator
> 
> Hermann, this looks like an extra subject line here?
> 
> > Banana Pi M2 Ultra V1.1 board resets immediately when the usb core
> > tries
> > to setup PH23 GPIO. It turned out that the V1.0 board USB-A ports
> > are
> > always power supplied and according to the board scheme PH23 is
> > simply
> > not connected.
> > 
> > So remove the PH23 setup: Doesn't harm V1.0 (with R40) and let V1.1
> > (with A40i) start.
> > 
> > Signed-off-by: Hermann Lauer <Hermann.Lauer@...-heidelberg.de>
> 
> The patch itself looks good to me, but it would be good to clarify
> the
> situation with the "older newer" version.
> 
> Just in case:
> Reviewed-by: Andre Przywara <andre.przywara@....com>
> 
> Cheers,
> Andre
>  
> > ---
> > V2: shorten subject, rm dangerous PH23 regulator completely
> > 
> > diff --git a/arch/arm/boot/dts/allwinner/sun8i-r40-bananapi-m2-
> > ultra.dts b/arch/arm/boot/dts/allwinner/sun8i-r40-bananapi-m2-
> > ultra.dts
> > --- a/arch/arm/boot/dts/allwinner/sun8i-r40-bananapi-m2-ultra.dts
> > +++ b/arch/arm/boot/dts/allwinner/sun8i-r40-bananapi-m2-ultra.dts
> > @@ -91,15 +91,6 @@
> >                 };
> >         };
> >  
> > -       reg_vcc5v0: vcc5v0 {
> > -               compatible = "regulator-fixed";
> > -               regulator-name = "vcc5v0";
> > -               regulator-min-microvolt = <5000000>;
> > -               regulator-max-microvolt = <5000000>;
> > -               gpio = <&pio 7 23 GPIO_ACTIVE_HIGH>; /* PH23 */
> > -               enable-active-high;
> > -       };
> > -
> >         wifi_pwrseq: pwrseq {
> >                 compatible = "mmc-pwrseq-simple";
> >                 reset-gpios = <&pio 6 10 GPIO_ACTIVE_LOW>; /* PG10
> > WIFI_EN */
> > @@ -347,7 +338,5 @@
> >  };
> >  
> >  &usbphy {
> > -       usb1_vbus-supply = <&reg_vcc5v0>;
> > -       usb2_vbus-supply = <&reg_vcc5v0>;
> >         status = "okay";
> >  };
> > 
> 
>