Re: [PATCH v15 7/7] riscv: dts: thead: Add PWM fan and thermal control

[Elle Rhumsaa <elle@weathered-steel.dev>]

On Tue, Sep 30, 2025 at 02:20:38PM +0200, Michal Wilczynski wrote:
> 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.
> 
> Reviewed-by: Drew Fustini <fustini@kernel.org>
> Tested-by: Drew Fustini <fustini@kernel.org>
> Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
> 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
> 

Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>