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Date:   Thu, 3 Dec 2020 10:23:01 +0200
From:   Krzysztof Kozlowski <krzk@kernel.org>
To:     Timon =?utf-8?B?QsOkdHo=?= <timon.baetz@protonmail.com>
Cc:     Sebastian Reichel <sre@kernel.org>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Kukjin Kim <kgene@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-samsung-soc@vger.kernel.org" 
        <linux-samsung-soc@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "~postmarketos/upstreaming@lists.sr.ht" 
        <~postmarketos/upstreaming@lists.sr.ht>
Subject: Re: [PATCH 3/3] ARM: dts: exynos: Fix charging regulator voltage and
 current for i9100
Message-ID: <20201203082301.GA3999@kozik-lap>
References: <20201202203516.43053-1-timon.baetz@protonmail.com>
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On Thu, Dec 03, 2020 at 05:46:03AM +0000, Timon Bätz wrote:
> On Wednesday, December 2, 2020 11:04 PM, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> 
> > On Wed, Dec 02, 2020 at 09:07:28PM +0000, Timon Baetz wrote:
> >
> > > Set CHARGER current and CHARGER_CV voltage according to Galaxy S2 kernel
> > > fork.
> > >
> > > Signed-off-by: Timon Baetz timon.baetz@protonmail.com
> > >
> > > ------------------------------------------------------
> > >
> > > arch/arm/boot/dts/exynos4210-i9100.dts | 8 ++++----
> > > 1 file changed, 4 insertions(+), 4 deletions(-)
> > > diff --git a/arch/arm/boot/dts/exynos4210-i9100.dts b/arch/arm/boot/dts/exynos4210-i9100.dts
> > > index 9f8d927e0d21..2700d53ea01b 100644
> > > --- a/arch/arm/boot/dts/exynos4210-i9100.dts
> > > +++ b/arch/arm/boot/dts/exynos4210-i9100.dts
> > > @@ -558,14 +558,14 @@ safe2_sreg: ESAFEOUT2 {
> > >
> > >       	charger_reg: CHARGER {
> > >       		regulator-name = "CHARGER";
> > >
> > >
> > > -       		regulator-min-microamp = <60000>;
> > >
> > >
> > > -       		regulator-max-microamp = <2580000>;
> > >
> > >
> > >
> > > -       		regulator-min-microamp = <200000>;
> > >
> > >
> > > -       		regulator-max-microamp = <950000>;
> > >         	};
> > >
> > >         	chargercv_reg: CHARGER_CV {
> > >         		regulator-name = "CHARGER_CV";
> > >
> > >
> > >
> > > -       		regulator-min-microvolt = <3800000>;
> > >
> > >
> > > -       		regulator-max-microvolt = <4100000>;
> > >
> > >
> > >
> > > -       		regulator-min-microvolt = <4200000>;
> > >
> > >
> > > -       		regulator-max-microvolt = <4200000>;
> > >
> > >
> >
> > I am looking at my sources of Android 3.0 for GT-I9100 but I cannot find
> > charger voltages for it. Where did you find it?
> >
> > Best regards,
> > Krzysztof
> 
> Thanks all the feedback Krzysztof,
> 
> Voltage is set in the charger probe function of the downstream kernel fork: https://github.com/LineageOS/android_kernel_samsung_smdk4412/blob/lineage-17.0/drivers/power/max8997_charger_u1.c#L390-L391

You need to fix your email client to wrap lines.

The fork cannot be used as a reference because of poor quality of
explanations for origins of the code.

The commit which added 4.2 V is described as "samsung update 1" which
basically means nothing. If at least it was "drop sources of
GT-I9105"... but in this form it is useless.

For the things we are not sure how they should be implemented, we
sometimes accept the reason "vendor sources do like this". However Lineage
or any other fork are not vendor sources.

Therefore you need to provide a valid explanation for this voltage
change.

Best regards,
Krzysztof