[PATCH v7 8/8] riscv: dts: thead: Add PWM fan and thermal control

Michal Wilczynski
2025-07-02T13:50:06Z

Add Device Tree nodes to enable a PWM controlled fan and it's associated
thermal management for the Lichee Pi 4A board.

This enables temperature-controlled active cooling for the Lichee Pi 4A
board based on SoC temperature.

Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
---
arch/riscv/boot/dts/thead/th1520-lichee-pi-4a.dts | 67 +++++++++++++++++++++++
1 file changed, 67 insertions(+)

diff --git a/arch/riscv/boot/dts/thead/th1520-lichee-pi-4a.dts b/arch/riscv/boot/dts/thead/th1520-lichee-pi-4a.dts
index 4020c727f09e8e2286fdc7fecd79dbd8eba69556..c58c2085ca92a3234f1350500cedae4157f0c35f 100644
--- a/arch/riscv/boot/dts/thead/th1520-lichee-pi-4a.dts
+++ b/arch/riscv/boot/dts/thead/th1520-lichee-pi-4a.dts
@@ -28,9 +28,76 @@ aliases {
chosen {
stdout-path = "serial0:115200n8";
};
+
+ thermal-zones {
+ cpu-thermal {
+ polling-delay = <1000>;
+ polling-delay-passive = <1000>;
+ thermal-sensors = <&pvt 0>;
+
+ trips {
+ fan_config0: fan-trip0 {
+ temperature = <39000>;
+ hysteresis = <5000>;
+ type = "active";
+ };
+
+ fan_config1: fan-trip1 {
+ temperature = <50000>;
+ hysteresis = <5000>;
+ type = "active";
+ };
+
+ fan_config2: fan-trip2 {
+ temperature = <60000>;
+ hysteresis = <5000>;
+ type = "active";
+ };
+ };
+
+ cooling-maps {
+ map-active-0 {
+ cooling-device = <&fan 1 1>;
+ trip = <&fan_config0>;
+ };
+
+ map-active-1 {
+ cooling-device = <&fan 2 2>;
+ trip = <&fan_config1>;
+ };
+
+ map-active-2 {
+ cooling-device = <&fan 3 3>;
+ trip = <&fan_config2>;
+ };
+ };
+ };
+ };
+
+ fan: pwm-fan {
+ pinctrl-names = "default";
+ pinctrl-0 = <&fan_pins>;
+ compatible = "pwm-fan";
+ #cooling-cells = <2>;
+ pwms = <&pwm 1 10000000 0>;
+ cooling-levels = <0 66 196 255>;
+ };
+
};

&padctrl0_apsys {
+ fan_pins: fan-0 {
+ pwm1-pins {
+ pins = "GPIO3_3"; /* PWM1 */
+ function = "pwm";
+ bias-disable;
+ drive-strength = <25>;
+ input-disable;
+ input-schmitt-disable;
+ slew-rate = <0>;
+ };
+ };
+
uart0_pins: uart0-0 {
tx-pins {
pins = "UART0_TXD";

--
2.34.1