[PATCH v3] arm64: dts: mediatek: mt7986-bpi-r3: Change fan PWM value for mid speed

[PATCH v3] arm64: dts: mediatek: mt7986-bpi-r3: Change fan PWM value for mid speed

[Mikhail Kshevetskiy]

Popular cheap PWM fans for this machine, like the ones coming in
heatsink+fan combos will not work properly at the currently defined
medium speed. Trying different pwm setting using a command

  echo $value > /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1

I found:

  pwm1 value     fan rotation speed   cpu temperature     notes
  -----------------------------------------------------------------
    0            maximal              31.5 Celsius        too noisy
   40            optimal              35.2 Celsius        no noise hearable
   95            minimal
   above 95      does not rotate      55.5 Celsius
  -----------------------------------------------------------------

Thus only cpu-active-high and cpu-active-low modes are usable.
I think this is wrong.

This patch fixes cpu-active-medium settings for bpi-r3 board.

I know, the patch is not ideal as it can break pwm fan for some users.
Likely this is the only official mt7986-bpi-r3 heatsink+fan solution
available on the market.

This patch may not be enough. Users may wants to tweak their thermal_zone0
trip points, thus tuning fan rotation speed depending on cpu temperature.
That can be done on the base of the following example:

  === example =========
  # cpu temperature below 25 Celsius degrees, no rotation
  echo 25000 > /sys/class/thermal/thermal_zone0/trip_point_4_temp
  # cpu temperature in [25..32] Celsius degrees, normal rotation speed
  echo 32000 > /sys/class/thermal/thermal_zone0/trip_point_3_temp
  # cpu temperature above 50 Celsius degrees, max rotation speed
  echo 50000 > /sys/class/thermal/thermal_zone0/trip_point_2_temp
  =====================

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>

---
From Frank Wunderlich <frank-w@public-files.de>
Date: 04.03.2025
>
> sorry for delay
>
> i have the fan from sinovoip and that was working for me, but if your fan only works with new values, i have no point against this change.

Frank, does it means that you are signed off this patch?

Changes from v1 to v2:
 * improve patch description

Changes from v2 to v3:
 * added question to Frank Wunderlich
---
 arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
index ed79ad1ae871..b0cc0cbdff0f 100644
--- a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
+++ b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
@@ -42,7 +42,7 @@ fan: pwm-fan {
 		compatible = "pwm-fan";
 		#cooling-cells = <2>;
 		/* cooling level (0, 1, 2) - pwm inverted */
-		cooling-levels = <255 96 0>;
+		cooling-levels = <255 40 0>;
 		pwms = <&pwm 0 10000>;
 		status = "okay";
 	};
-- 
2.47.2

Re: [PATCH v3] arm64: dts: mediatek: mt7986-bpi-r3: Change fan PWM value for mid speed

[Frank Wunderlich]

Am 26. Mai 2025 14:31:23 MESZ schrieb Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>:
>Popular cheap PWM fans for this machine, like the ones coming in
>heatsink+fan combos will not work properly at the currently defined
>medium speed. Trying different pwm setting using a command
>
>  echo $value > /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1
>
>I found:
>
>  pwm1 value     fan rotation speed   cpu temperature     notes
>  -----------------------------------------------------------------
>    0            maximal              31.5 Celsius        too noisy
>   40            optimal              35.2 Celsius        no noise hearable
>   95            minimal
>   above 95      does not rotate      55.5 Celsius
>  -----------------------------------------------------------------
>
>Thus only cpu-active-high and cpu-active-low modes are usable.
>I think this is wrong.
>
>This patch fixes cpu-active-medium settings for bpi-r3 board.
>
>I know, the patch is not ideal as it can break pwm fan for some users.
>Likely this is the only official mt7986-bpi-r3 heatsink+fan solution
>available on the market.
>
>This patch may not be enough. Users may wants to tweak their thermal_zone0
>trip points, thus tuning fan rotation speed depending on cpu temperature.
>That can be done on the base of the following example:
>
>  === example =========
>  # cpu temperature below 25 Celsius degrees, no rotation
>  echo 25000 > /sys/class/thermal/thermal_zone0/trip_point_4_temp
>  # cpu temperature in [25..32] Celsius degrees, normal rotation speed
>  echo 32000 > /sys/class/thermal/thermal_zone0/trip_point_3_temp
>  # cpu temperature above 50 Celsius degrees, max rotation speed
>  echo 50000 > /sys/class/thermal/thermal_zone0/trip_point_2_temp
>  =====================
>
>Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
>
>---
>From Frank Wunderlich <frank-w@public-files.de>
>Date: 04.03.2025
>>
>> sorry for delay
>>
>> i have the fan from sinovoip and that was working for me, but if your fan only works with new values, i have no point against this change.
>
>Frank, does it means that you are signed off this patch?

Let it count as

Acked-by: Frank Wunderlich <frank-w@public-files.de>

Because i cannot test these values,as i only have 1 pwm fan for r3 in my main router :p
Maybe R4 fan works too,but not yet tested.

Not sure if the complete testcase has to be in the commit description,but this is maintainers decision.

>Changes from v1 to v2:
> * improve patch description
>
>Changes from v2 to v3:
> * added question to Frank Wunderlich
>---
> arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
>index ed79ad1ae871..b0cc0cbdff0f 100644
>--- a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
>+++ b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
>@@ -42,7 +42,7 @@ fan: pwm-fan {
> 		compatible = "pwm-fan";
> 		#cooling-cells = <2>;
> 		/* cooling level (0, 1, 2) - pwm inverted */
>-		cooling-levels = <255 96 0>;
>+		cooling-levels = <255 40 0>;
> 		pwms = <&pwm 0 10000>;
> 		status = "okay";
> 	};


regards Frank

[PATCH v4] arm64: dts: mediatek: mt7986-bpi-r3: Change fan PWM value for mid speed

[Mikhail Kshevetskiy]

Popular cheap PWM fans for this machine, like the ones coming in
heatsink+fan combos will not work properly at the currently defined
medium speed. Trying different pwm setting using a command

  echo $value > /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1

I found:

  pwm1 value     fan rotation speed   cpu temperature     notes
  -----------------------------------------------------------------
    0            maximal              31.5 Celsius        too noisy
   40            optimal              35.2 Celsius        no noise hearable
   95            minimal
   above 95      does not rotate      55.5 Celsius
  -----------------------------------------------------------------

Thus only cpu-active-high and cpu-active-low modes are usable.
I think this is wrong.

This patch fixes cpu-active-medium settings for bpi-r3 board.

I know, the patch is not ideal as it can break pwm fan for some users.
Likely this is the only official mt7986-bpi-r3 heatsink+fan solution
available on the market.

This patch may not be enough. Users may wants to tweak their thermal_zone0
trip points, thus tuning fan rotation speed depending on cpu temperature.
That can be done on the base of the following example:

  === example =========
  # cpu temperature below 25 Celsius degrees, no rotation
  echo 25000 > /sys/class/thermal/thermal_zone0/trip_point_4_temp
  # cpu temperature in [25..32] Celsius degrees, normal rotation speed
  echo 32000 > /sys/class/thermal/thermal_zone0/trip_point_3_temp
  # cpu temperature above 50 Celsius degrees, max rotation speed
  echo 50000 > /sys/class/thermal/thermal_zone0/trip_point_2_temp
  =====================

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Acked-by: Frank Wunderlich <frank-w@public-files.de>

---
Changes from v1 to v2:
 * improve patch description

Changes from v2 to v3:
 * added question to Frank Wunderlich

Changes from v3 to v4:
 * Acked by Frank Wunderlich
---
 arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
index ed79ad1ae871..b0cc0cbdff0f 100644
--- a/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
+++ b/arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dts
@@ -42,7 +42,7 @@ fan: pwm-fan {
 		compatible = "pwm-fan";
 		#cooling-cells = <2>;
 		/* cooling level (0, 1, 2) - pwm inverted */
-		cooling-levels = <255 96 0>;
+		cooling-levels = <255 40 0>;
 		pwms = <&pwm 0 10000>;
 		status = "okay";
 	};
-- 
2.47.2

Re: [PATCH v4] arm64: dts: mediatek: mt7986-bpi-r3: Change fan PWM value for mid speed

[AngeloGioacchino Del Regno]

Il 29/07/25 09:56, Mikhail Kshevetskiy ha scritto:
> Popular cheap PWM fans for this machine, like the ones coming in
> heatsink+fan combos will not work properly at the currently defined
> medium speed. Trying different pwm setting using a command
> 
>    echo $value > /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1
> 
> I found:
> 
>    pwm1 value     fan rotation speed   cpu temperature     notes
>    -----------------------------------------------------------------
>      0            maximal              31.5 Celsius        too noisy
>     40            optimal              35.2 Celsius        no noise hearable
>     95            minimal
>     above 95      does not rotate      55.5 Celsius
>    -----------------------------------------------------------------
> 
> Thus only cpu-active-high and cpu-active-low modes are usable.
> I think this is wrong.
> 
> This patch fixes cpu-active-medium settings for bpi-r3 board.
> 
> I know, the patch is not ideal as it can break pwm fan for some users.
> Likely this is the only official mt7986-bpi-r3 heatsink+fan solution
> available on the market.
> 
> This patch may not be enough. Users may wants to tweak their thermal_zone0
> trip points, thus tuning fan rotation speed depending on cpu temperature.
> That can be done on the base of the following example:
> 
>    === example =========
>    # cpu temperature below 25 Celsius degrees, no rotation
>    echo 25000 > /sys/class/thermal/thermal_zone0/trip_point_4_temp
>    # cpu temperature in [25..32] Celsius degrees, normal rotation speed
>    echo 32000 > /sys/class/thermal/thermal_zone0/trip_point_3_temp
>    # cpu temperature above 50 Celsius degrees, max rotation speed
>    echo 50000 > /sys/class/thermal/thermal_zone0/trip_point_2_temp
>    =====================
> 
> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
> Acked-by: Frank Wunderlich <frank-w@public-files.de>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>