linux-kernel - Re: [PATCH v4 09/12] arm64: dts: qcom: sdm845-lg-common: Add camera flash

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Message-ID: <9cdccbb5a3fb10a2d7de1e1d17d36018f40b18a1@postmarketos.org>
Date: Wed, 03 Dec 2025 09:27:40 +0000
From: "Paul Sajna" <sajattack@...tmarketos.org>
To: "Konrad Dybcio" <konrad.dybcio@....qualcomm.com>, "Bjorn Andersson"
 <andersson@...nel.org>, "Konrad Dybcio" <konradybcio@...nel.org>, "Rob
 Herring" <robh@...nel.org>, "Krzysztof Kozlowski" <krzk+dt@...nel.org>,
 "Conor Dooley" <conor+dt@...nel.org>, "David Heidelberg" <david@...t.cz>
Cc: linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, phone-devel@...r.kernel.org, "Amir Dahan"
 <system64fumo@...tonmail.com>, "Christopher Brown"
 <crispybrown@...il.com>
Subject: Re: [PATCH v4 09/12] arm64: dts: qcom: sdm845-lg-common: Add camera
 flash

linux-postmarketos-qcom-sdm845-6.16.7_p20251203010632-r0.apk


December 1, 2025 at 11:42 AM, "Konrad Dybcio" <konrad.dybcio@....qualcomm.com mailto:konrad.dybcio@....qualcomm.com?to=%22Konrad%20Dybcio%22%20%3Ckonrad.dybcio%40oss.qualcomm.com%3E > wrote:


> 
> On 11/28/25 9:20 PM, Paul Sajna wrote:
> 
> > 
> > I did more testing on this, and the led only comes on if it's brightness is set to approx 150/255 or lower. In that case, should I set led-max-microamp to 60mA?
> > 
> FWIW your downstream kernel sets up channels 0 and 1, here you only
> enabled 1. Taking a look at a picture of the phone, I only see a single
> LED on the back, so perhaps you're (over)driving a single power line?
> 
> I'm not a milion percent sure, but I would assume the current draw
> *limiting* register applies to the sum of the current going through
> the three channels because there's only a single instance of it.
> 
> Konrad
>

I tried setting up both, but only the one that was mapped as `led-sources = <2>` seemed to have any effect. Also it would confuse userspace flashlight apps if there were two I think. So I'll push v5 with just the one that does anything.