On 2021-08-13 13:59, Daniel Lezcano wrote:

On 30/07/2021 17:17, Peter Geis wrote:

quoted

The rockpro64 had a fan node since
commit 5882d65c1691 ("arm64: dts: rockchip: Add PWM fan for RockPro64")
however it was never tied into the thermal driver for automatic control.

Add the links to the thermal node to permit the kernel to handle this
automatically.
Borrowed from the (rk3399-khadas-edge.dtsi).

Signed-off-by: Peter Geis <redacted>
---

Changelog:
v3:
Removed the gpu nodes to prevent in-fighting (thanks Robin!)

v2:
Adjusted fan setpoints for less noise

  .../boot/dts/rockchip/rk3399-rockpro64.dtsi   | 29 +++++++++++++++++++
  1 file changed, 29 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi
index 6bff8db7d33e..83db4ca67334 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-rockpro64.dtsi

@@ -69,6 +69,7 @@ diy_led: led-1 {
  
  	fan: pwm-fan {
  		compatible = "pwm-fan";
+		cooling-levels = <0 100 150 200 255>;
  		#cooling-cells = <2>;
  		fan-supply = <&vcc12v_dcin>;
  		pwms = <&pwm1 0 50000 0>;

@@ -245,6 +246,34 @@ &cpu_b1 {
  	cpu-supply = <&vdd_cpu_b>;
  };
  
+&cpu_thermal {
+	trips {
+		cpu_warm: cpu_warm {
+			temperature = <55000>;
+			hysteresis = <2000>;
+			type = "active";
+		};
+
+		cpu_hot: cpu_hot {
+			temperature = <65000>;
+			hysteresis = <2000>;
+			type = "active";
+		};
+	};
+

Why two trip points ?

Why not one functioning temperature and no lower / upper limits for the
cooling maps ?

Certainly when I first did this for NanoPC-T4, IIRC it was to avoid the 
fan ramping up too eagerly, since level 1 for my fan is effectively 
silent but still cools enough to let a moderate load eventually settle 
to a steady state below the second trip.

Robin.

quoted

+	cooling-maps {
+		map2 {
+			trip = <&cpu_warm>;
+			cooling-device = <&fan THERMAL_NO_LIMIT 1>;
+		};
+
+		map3 {
+			trip = <&cpu_hot>;
+			cooling-device = <&fan 2 THERMAL_NO_LIMIT>;
+		};
+	};
+};
+
  &emmc_phy {
  	status = "okay";
  };