linux-kernel - Re: [PATCH] arm64: dts: meson: Enable active coling using gpio-fan on Odroid N2/N2+

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Message-ID: <CANAwSgQhWrzeRcpQSSAmfp+i3966dUQdtCLbcWwifQk=1ce=og@mail.gmail.com>
Date:   Wed, 19 Oct 2022 22:46:55 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     neil.armstrong@...aro.org
Cc:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: dts: meson: Enable active coling using gpio-fan on
 Odroid N2/N2+

Hi Neil

On Wed, 19 Oct 2022 at 16:39, Neil Armstrong <neil.armstrong@...aro.org> wrote:
>
> Hi Anand,
>
> On 19/10/2022 11:48, Anand Moon wrote:
> > Hi Martin,
> >
> > On Wed, 19 Oct 2022 at 08:36, Anand Moon <linux.amoon@...il.com> wrote:
> >>
> >> Hi Martin,
> >>
> >> On Wed, 19 Oct 2022 at 02:46, Martin Blumenstingl
> >> <martin.blumenstingl@...glemail.com> wrote:
> >>>
> >>> Hello Anand,
> >>>
> >>> On Tue, Oct 18, 2022 at 9:53 PM Anand Moon <linux.amoon@...il.com> wrote:
> >>>>
> >>>> Odroid N2/N2+ support active cooling via gpio-fan controller.
> >>>> Add fan controls and tip point for cpu and ddr thermal sensor
> >>>> on this boards.
> >>> In the schematics for board rev 0.6 [0] I cannot find any information
> >>> about a fan connector.
> >>> The schematics for board rev 0.3 [1] on the other hand document a PWM
> >>> based fan connector on page 16.
> >>> So now I am not sure whether your patch only applies to certain board
> >>> revisions, the schematics are incorrect, etc.
> >>>
> >>> Can you please provide some details about the fan connector on
> >>> Odroid-N2/N2+ and which hardware revisions are supported (and which
> >>> aren't) by your patch?
> >>>
> >>>
> >> Ok I got this wrong the schematics below there is pwm controller, not
> >> gpio controller
> >> GPIOAO.BIT10 (PWM)
> >> I will correct the patch sorry for the mistake I did not look more carefully.
> >>
> >
> > As per the schematics GPIOAO_10 is controlled by PWMAO_D
> > But looking into the datasheet [0] I could not find the relevant
> > PWMAO_D pmw ip block to link the fan to the PWM controller.
> >
> > [0] https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf
> >
> > I could get the PWM node but is not working for me.
> >
> > @@ -547,6 +588,14 @@ &pwm_ab {
> >          status = "okay";
> >   };
> >
> > +&pwm_AO_ab {
>
> &pwm_AO_cd not _ab
>
No it has a conflict with CPU_B (vddcpu_b) PWM

I have tried linking all the PWM with pwm-fan but it's not working.

# sudo cat /sys/kernel/debug/pwm
platform/ffd1b000.pwm, 2 PWM devices
 pwm-0   (regulator-vddcpu-a  ): requested enabled period: 1250 ns
duty: 0 ns polarity: normal
 pwm-1   ((null)              ): period: 0 ns duty: 0 ns polarity: normal

platform/ff807000.pwm, 2 PWM devices
 pwm-0   ((null)              ): period: 0 ns duty: 0 ns polarity: normal
 pwm-1   (pwm-fan             ): requested period: 1250 ns duty: 0 ns
polarity: normal

platform/ff802000.pwm, 2 PWM devices
 pwm-0   ((null)              ): period: 0 ns duty: 0 ns polarity: normal
 pwm-1   (regulator-vddcpu-b  ): requested enabled period: 1250 ns
duty: 88 ns polarity: normal

Thanks
-Anand