linux-kernel - Re: [PATCH v7 6/6] arm64: dts: qcom: Add Xiaomi Redmi 3S

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Message-Id: <DD038IVOWESM.24X3EZZXH3UE@fairphone.com>
Date: Tue, 23 Sep 2025 11:55:41 +0200
From: "Luca Weiss" <luca.weiss@...rphone.com>
To: "Pavel Machek" <pavel@....cz>, <barnabas.czeman@...nlining.org>
Cc: "Bjorn Andersson" <andersson@...nel.org>, "Michael Turquette"
 <mturquette@...libre.com>, "Stephen Boyd" <sboyd@...nel.org>, "Rob Herring"
 <robh@...nel.org>, "Krzysztof Kozlowski" <krzk+dt@...nel.org>, "Conor
 Dooley" <conor+dt@...nel.org>, "Stephan Gerhold" <stephan@...hold.net>,
 Otto Pflüger <otto.pflueger@...cue.de>, "Linus Walleij"
 <linus.walleij@...aro.org>, "Lee Jones" <lee@...nel.org>, "Joerg Roedel"
 <joro@...tes.org>, "Will Deacon" <will@...nel.org>, "Robin Murphy"
 <robin.murphy@....com>, "Konrad Dybcio" <konradybcio@...nel.org>, "Sean
 Paul" <sean@...rly.run>, "Abhinav Kumar" <quic_abhinavk@...cinc.com>,
 "Marijn Suijten" <marijn.suijten@...ainline.org>, "David Airlie"
 <airlied@...il.com>, "Simona Vetter" <simona@...ll.ch>, "Maarten Lankhorst"
 <maarten.lankhorst@...ux.intel.com>, "Maxime Ripard" <mripard@...nel.org>,
 "Thomas Zimmermann" <tzimmermann@...e.de>, "Dmitry Baryshkov"
 <lumag@...nel.org>, "Adam Skladowski" <a_skl39@...tonmail.com>, "Sireesh
 Kodali" <sireeshkodali@...tonmail.com>, "Rob Clark"
 <robin.clark@....qualcomm.com>, "Abhinav Kumar" <abhinav.kumar@...ux.dev>,
 "Jessica Zhang" <jessica.zhang@....qualcomm.com>, "Srinivas Kandagatla"
 <srini@...nel.org>, <linux-arm-msm@...r.kernel.org>,
 <linux-clk@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
 <iommu@...ts.linux.dev>, <dri-devel@...ts.freedesktop.org>,
 <freedreno@...ts.freedesktop.org>, <phone-devel@...r.kernel.org>,
 <~postmarketos/upstreaming@...ts.sr.ht>, <linux@...nlining.org>, "Konrad
 Dybcio" <konrad.dybcio@....qualcomm.com>
Subject: Re: [PATCH v7 6/6] arm64: dts: qcom: Add Xiaomi Redmi 3S

Hi Pavel and Barnabas,

On Tue Sep 23, 2025 at 9:22 AM CEST, Pavel Machek wrote:
> Hi!
>> > Hi!
>> > 
>> > > +	led-controller@45 {
>> > > +		compatible = "awinic,aw2013";
>> > > +		reg = <0x45>;
>> > > +		#address-cells = <1>;
>> > > +		#size-cells = <0>;
>> > > +
>> > > +		vcc-supply = <&pm8937_l10>;
>> > > +		vio-supply = <&pm8937_l5>;
>> > > +
>> > > +		led@0 {
>> > > +			reg = <0>;
>> > > +			function = LED_FUNCTION_STATUS;
>> > > +			led-max-microamp = <5000>;
>> > > +			color = <LED_COLOR_ID_RED>;
>> > > +		};
>> > > +
>> > > +		led@1 {
>> > > +			reg = <1>;
>> > > +			function = LED_FUNCTION_STATUS;
>> > > +			led-max-microamp = <5000>;
>> > > +			color = <LED_COLOR_ID_GREEN>;
>> > > +		};
>> > > +
>> > > +		led@2 {
>> > > +			reg = <2>;
>> > > +			function = LED_FUNCTION_STATUS;
>> > > +			led-max-microamp = <5000>;
>> > > +			color = <LED_COLOR_ID_BLUE>;
>> > > +		};
>> > > +	};
>> > > +};
>> > 
>> > That's single, 3-color LED, right? Please see LED multicolor support.
>> As far as i know aw2013 driver does not have multicolor support.
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/devicetree/bindings/leds/leds-aw2013.yaml
>
> I believe that needs to be fixed before more bugs are added on top to
> work around that problem...
>
> ...and before that bug is cemented in the ABI.

Honestly I don't think it's reasonable to expect people contributing dts
to then first start patching existing LED drivers and adding support for
x y or z to it, and block dts addition on that.

At least in postmarketOS the user space components we have (e.g.
feedbackd) detect the LED things (and most others) automatically since
various devices have various different setups. So once/if aw2013 gets
multicolor support, the dts can be updated without problems.

Sure, maybe today changing something on the N900 which would change
sysfs paths is not the best idea because people will probably have 10+
years of random shell scripts lying around, but nowadays we usually have
better ways of abstraction that can handle that.

Regards
Luca

>
> Best regards,
> 								Pavel