Brooklyn/arch/arm/boot/dts/overlays/ghost-amp-overlay.dts

// Overlay for the PCM5122-based Ghost amplifier using gpio-fsm
/dts-v1/;
/plugin/;

#include <dt-bindings/gpio/gpio-fsm.h>

#define ENABLE   GF_SW(0)
#define FAULT    GF_IP(0) // GPIO5
#define RELAY1   GF_OP(0) // GPIO22
#define RELAY2   GF_OP(1) // GPIO23
#define RELAYSSR GF_OP(2) // GPIO24

/ {
	compatible = "brcm,bcm2835";

	fragment@0 {
		target = <&i2s>;
		__overlay__ {
			status = "okay";
		};
	};

	fragment@1 {
		target = <&i2c1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			status = "okay";

			pcm5122@4c {
				#sound-dai-cells = <0>;
				compatible = "ti,pcm5122";
				reg = <0x4c>;
				AVDD-supply = <&vdd_3v3_reg>;
				DVDD-supply = <&vdd_3v3_reg>;
				CPVDD-supply = <&vdd_3v3_reg>;
				status = "okay";
			};
		};
	};

	fragment@2 {
		target = <&sound>;
		iqaudio_dac: __overlay__ {
			compatible = "iqaudio,iqaudio-dac";
			i2s-controller = <&i2s>;
			mute-gpios = <&amp 0 0>;
			iqaudio-dac,auto-mute-amp;
			status = "okay";
		};
	};

	fragment@3 {
		target-path = "/";
		__overlay__ {
			amp: ghost-amp {
				compatible = "rpi,gpio-fsm";
				pinctrl-names = "default";
				pinctrl-0 = <&ghost_amp_pins>;

				debug = <0>;
				gpio-controller;
				#gpio-cells = <2>;
				num-swgpios = <1>;
				gpio-line-names = "enable";
				input-gpios  = <&gpio 5 1>;  // FAULT (active low)
				output-gpios = <&gpio 22 0>, // RELAY1
					       <&gpio 23 0>, // RELAY2
					       <&gpio 24 0>; // RELAYSSR
				shutdown-timeout-ms = <1000>;

				amp_off {
					start_state;
					shutdown_state;

					set = <RELAYSSR 0>,
					      <RELAY2 0>,
					      <RELAY1 0>;
					amp_on_1 = <ENABLE 1>;
					fault = <FAULT 1>;
				};

				amp_on_1 {
					set = <RELAY1 1>;
					amp_on_2 = <GF_DELAY 1000>;
					amp_off = <GF_SHUTDOWN 0>;
					fault = <FAULT 1>;
				};

				amp_on_2 {
					set = <RELAY2 1>;
					amp_on_wait = <ENABLE 0>;
					amp_on = <GF_DELAY 1>;
					fault = <FAULT 1>;
				};

				amp_on {
					set = <RELAYSSR 1>;
					amp_on_wait = <ENABLE 0>;
					fault = <FAULT 1>;
				};

				amp_on_wait {
					set = <RELAYSSR 0>;
					amp_off_1 = <GF_DELAY (30*60*1000)>,
						    <GF_SHUTDOWN 0>;
					amp_on = <ENABLE 1>;
					fault = <FAULT 1>;
				};

				amp_off_1 {
					set = <RELAY2 0>;
					amp_on = <ENABLE 1>;
					amp_off = <GF_DELAY 100>;
					fault = <FAULT 1>;
				};

				// Keep this a distinct state to prevent
				// changes and for the diagnostic output
				fault {
					set = <RELAYSSR 0>,
					      <RELAY2 0>,
					      <RELAY1 0>;
					amp_off = <FAULT 0>;
					shutdown_state;
				};
			};
		};
	};

	fragment@4 {
		target = <&gpio>;
		__overlay__ {
			ghost_amp_pins: ghost_amp_pins {
				brcm,pins = <5 22 23 24>;
				brcm,function = <0 1 1 1>; /* in out out out */
				brcm,pull = <2 0 0 0>; /* up none none none */
			};
		};
	};

	__overrides__ {
		fsm_debug = <&amp>,"debug:0";
	};
};