The A311D on Zero2 needs active cooling and the board includes a header to
connect a simple fan. Add pwm-fan support with basic thermal properties so
the fan runs when connected.

Suggested-by: Yuntian Zhang <yt@radxa.com>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
---
 .../dts/amlogic/meson-g12b-radxa-zero2.dts    | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
index 890f5bfebb03..895b6ea67180 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
@@ -33,6 +33,15 @@ memory@0 {
 		reg = <0x0 0x0 0x0 0x80000000>;
 	};
 
+	fan0: pwm-fan {
+		compatible = "pwm-fan";
+		#cooling-cells = <2>;
+		cooling-min-state = <0>;
+		cooling-max-state = <4>;
+		cooling-levels = <0 64 128 192 255>;
+		pwms = <&pwm_AO_ab 0 40000 0>;
+	};
+
 	gpio-keys-polled {
 		compatible = "gpio-keys-polled";
 		poll-interval = <100>;
@@ -286,6 +295,24 @@ &cpu103 {
 	clock-latency = <50000>;
 };
 
+&cpu_thermal {
+	cooling-maps {
+		map0 {
+			trip = <&cpu_passive>;
+			cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+		};
+	};
+};
+
+&ddr_thermal {
+	cooling-maps {
+		map0 {
+			trip = <&ddr_passive>;
+			cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+		};
+	};
+};
+
 &frddr_a {
 	status = "okay";
 };
-- 
2.34.1

On 28/10/2023 09:54, Christian Hewitt wrote:
> The A311D on Zero2 needs active cooling and the board includes a header to
> connect a simple fan. Add pwm-fan support with basic thermal properties so
> the fan runs when connected.
> 
> Suggested-by: Yuntian Zhang <yt@radxa.com>
> Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
> ---
>   .../dts/amlogic/meson-g12b-radxa-zero2.dts    | 27 +++++++++++++++++++
>   1 file changed, 27 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
> index 890f5bfebb03..895b6ea67180 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
> +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-radxa-zero2.dts
> @@ -33,6 +33,15 @@ memory@0 {
>   		reg = <0x0 0x0 0x0 0x80000000>;
>   	};
>   
> +	fan0: pwm-fan {
> +		compatible = "pwm-fan";
> +		#cooling-cells = <2>;
> +		cooling-min-state = <0>;
> +		cooling-max-state = <4>;
> +		cooling-levels = <0 64 128 192 255>;
> +		pwms = <&pwm_AO_ab 0 40000 0>;
> +	};
> +
>   	gpio-keys-polled {
>   		compatible = "gpio-keys-polled";
>   		poll-interval = <100>;
> @@ -286,6 +295,24 @@ &cpu103 {
>   	clock-latency = <50000>;
>   };
>   
> +&cpu_thermal {
> +	cooling-maps {
> +		map0 {
> +			trip = <&cpu_passive>;
> +			cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +		};
> +	};
> +};
> +
> +&ddr_thermal {
> +	cooling-maps {
> +		map0 {
> +			trip = <&ddr_passive>;
> +			cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +		};
> +	};
> +};

You should instead add a new active trips, and use them for the fan cooling-map.

Look at how it's done on the Khadas VIM3s or Odroid boards.

Neil

> +
>   &frddr_a {
>   	status = "okay";
>   };