Brooklyn/arch/arm/boot/dts/overlays/rotary-encoder-overlay.dts

// Device tree overlay for GPIO connected rotary encoder.
/dts-v1/;
/plugin/;

/ {
	compatible = "brcm,bcm2835";

	fragment@0 {
		target = <&gpio>;
		__overlay__ {
			rotary_pins: rotary_pins@4 {
				brcm,pins = <4 17>; /* gpio 4 17 */
				brcm,function = <0 0>; /* input */
				brcm,pull = <2 2>; /* pull-up */
			};

		};
	};

	fragment@1 {
		target-path = "/";
		__overlay__ {
			rotary: rotary@4 {
				compatible = "rotary-encoder";
				status = "okay";
				pinctrl-names = "default";
				pinctrl-0 = <&rotary_pins>;
				gpios = <&gpio 4 0>, <&gpio 17 0>;
				linux,axis = <0>; /* REL_X */
				rotary-encoder,encoding = "gray";
				rotary-encoder,steps = <24>; /* 24 default */
				rotary-encoder,steps-per-period = <1>; /* corresponds to full period mode. See README */
			};
		};

	};  

	__overrides__ {
		pin_a =		    <&rotary>,"gpios:4",
				    <&rotary_pins>,"brcm,pins:0",
				    /* modify reg values to allow multiple instantiation */
				    <&rotary>,"reg:0",
				    <&rotary_pins>,"reg:0";
		pin_b =		    <&rotary>,"gpios:16",
				    <&rotary_pins>,"brcm,pins:4";
		relative_axis =     <&rotary>,"rotary-encoder,relative-axis?";
		linux_axis =        <&rotary>,"linux,axis:0";
		rollover =          <&rotary>,"rotary-encoder,rollover?";
		steps-per-period =  <&rotary>,"rotary-encoder,steps-per-period:0";
		steps =             <&rotary>,"rotary-encoder,steps:0";
		wakeup =            <&rotary>,"wakeup-source?";
		encoding =          <&rotary>,"rotary-encoder,encoding";
                /* legacy parameters*/
		rotary0_pin_a =     <&rotary>,"gpios:4",
		                    <&rotary_pins>,"brcm,pins:0";
		rotary0_pin_b =     <&rotary>,"gpios:16",
		                    <&rotary_pins>,"brcm,pins:4";
	};
};