linux-kernel - Re: [PATCH] arm64: dts: qcom: milos-fairphone-fp6: Add Hall Effect sensor

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Message-Id: <DFU439A9HP2H.1Y9OS2OPAXGOI@fairphone.com>
Date: Wed, 21 Jan 2026 09:07:44 +0100
From: "Luca Weiss" <luca.weiss@...rphone.com>
To: "Dmitry Baryshkov" <dmitry.baryshkov@....qualcomm.com>, "Luca Weiss"
 <luca.weiss@...rphone.com>, "Dmitry Torokhov" <dmitry.torokhov@...il.com>
Cc: "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>,
 <~postmarketos/upstreaming@...ts.sr.ht>, <phone-devel@...r.kernel.org>,
 <linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <linux-input@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: qcom: milos-fairphone-fp6: Add Hall Effect
 sensor

On Wed Jan 21, 2026 at 12:05 AM CET, Dmitry Baryshkov wrote:
> On Mon, Jan 19, 2026 at 04:52:23PM +0100, Luca Weiss wrote:
>> On Mon Jan 19, 2026 at 3:41 PM CET, Konrad Dybcio wrote:
>> > On 1/16/26 3:22 PM, Luca Weiss wrote:
>> >> Add a node for the Hall Effect sensor, used to detect whether the Flip
>> >> Cover is closed or not.
>> >> 
>> >> The sensor is powered through vreg_l10b, so let's put a
>> >> regulator-always-on on that to make sure the sensor gets power.
>> >
>> > Is there anything else on L10B? Can we turn it off if the hall sensor
>> > is e.g. user-disabled?
>> 
>> It's the voltage source for pull-up of sensor I2C bus (so
>> ADSP-managed?), DVDD for amplifiers and VDD for a most sensors like
>> the gyro.
>> 
>> So realistically, it'll probably be (nearly) always on anyways. And I
>> don't want to shave another yak by adding vdd support to gpio-keys...
>
> Why? If it is exactly what happens on the board: the device producing
> GPIO events _is_ powered via a vdd. Added Input maintainer / list to cc.

Yes, the hall sensor which is connected to the GPIO on the SoC, has an
extra VDD input which needs to be on in order for the Hall-effect sensor
to be on.

See page 133 "HALL" in the center of the page
https://www.fairphone.com/wp-content/uploads/2025/08/Fairphone-Gen.-6_-Information-on-how-to-repair-dispose-of-and-recycle-EN-NL-FR-DE.pdf

The IC is OCH166AEV4AD where VDD is (as expected) "Power Supply Input":
https://www.orient-chip.com/Public/Uploads/uploadfile/files/20231014/1OCH166Adatasheet202203221.pdf

Regards
Luca

>
>> 
>> Regards
>> Luca
>> 
>> >
>> > Konrad
>> >
>> >> 
>> >> Signed-off-by: Luca Weiss <luca.weiss@...rphone.com>
>> >> ---
>> >>  arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts | 12 ++++++++++++
>> >>  1 file changed, 12 insertions(+)
>> >> 
>> >> diff --git a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
>> >> index 7629ceddde2a..98b3fc654206 100644
>> >> --- a/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
>> >> +++ b/arch/arm64/boot/dts/qcom/milos-fairphone-fp6.dts
>> >> @@ -32,6 +32,16 @@ gpio-keys {
>> >>  		pinctrl-0 = <&volume_up_default>;
>> >>  		pinctrl-names = "default";
>> >>  
>> >> +		/* Powered by the always-on vreg_l10b */
>> >> +		event-hall-sensor {
>> >> +			label = "Hall Effect Sensor";
>> >> +			gpios = <&tlmm 70 GPIO_ACTIVE_LOW>;
>> >> +			linux,input-type = <EV_SW>;
>> >> +			linux,code = <SW_LID>;
>> >> +			linux,can-disable;
>> >> +			wakeup-source;
>> >> +		};
>> >> +
>> >>  		key-volume-up {
>> >>  			label = "Volume Up";
>> >>  			gpios = <&pm7550_gpios 6 GPIO_ACTIVE_LOW>;
>> >> @@ -316,6 +326,8 @@ vreg_l10b: ldo10 {
>> >>  			regulator-min-microvolt = <1800000>;
>> >>  			regulator-max-microvolt = <1800000>;
>> >>  			regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
>> >> +			/* Hall sensor VDD */
>> >> +			regulator-always-on;
>> >>  		};
>> >>  
>> >>  		vreg_l11b: ldo11 {
>> >> 
>> >> ---
>> >> base-commit: ef1c7b875741bef0ff37ae8ab8a9aaf407dc141c
>> >> change-id: 20260116-fp6-hall-sensor-1049f2f872ac
>> >> 
>> >> Best regards,
>>