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

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Message-ID: <dfe91e99-a686-415b-9211-7cb774e5343c@oss.qualcomm.com>
Date: Thu, 22 Jan 2026 09:32:08 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Luca Weiss <luca.weiss@...rphone.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....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 1/21/26 9:06 PM, Dmitry Torokhov wrote:
> On Wed, Jan 21, 2026 at 09:07:44AM +0100, Luca Weiss wrote:
>> 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
> 
> If we add regulator support to gpio-keys do we expect it to be
> per-gpio/per-key? Or we'd recommend splitting into several instances of
> gpio-keys so that there is on set of supplies per gpio-keys device?

gpio-keys {} is very broad and generic, I would imagine it would only
make sense to keep it per-entry, like Luca suggested

Konrad