sj201-buttons-overlay.dts

/*
 * Device Tree Overlay for SJ-201 Rev6&10 - XMOS VocalFusion 3510-INT
 *
 * This DTO is specifically designed to configure the GPIO pins for button inputs
 * on the SJ-201 board, facilitating user interactions through physical buttons.
 * These configurations include setting up GPIO pins for volume control,
 * wake-up, and microphone mute functionalities.
 *
 * Instructions:
 * Compile this DTO with the following command:
 * dtc -@ -H epapr -O dtb -o sj201-buttons-overlay.dtbo -Wno-unit_address_vs_reg sj201-buttons-overlay.dts
 */

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835";

    /* Configure GPIO pins for SJ201 keys */
    fragment@0 {
        target = <&gpio>;
        __overlay__ {
            sj201_key_pins: sj201_key_pins {
                /* GPIOs 22-24 are configured as momentary switches;
                   GPIO 25 is configured for the Microphone Mute switch. */
                brcm,pins = <22 23 24 25>; // Specify the GPIO pins to configure
                brcm,function = <0>; // Set pins to input mode
                brcm,pull = <0>;     // Disable pull-up/down for these pins
            };
        };
    };

    /* Define GPIO keys for volume control, wake-up, and microphone mute */
    fragment@1 {
        target-path = "/soc";

            __overlay__ {
                sj201_buttons: sj201_buttons {
                    compatible = "gpio-keys";
                    // #address-cells = <1>;
                    // #size-cells = <0>;
                    pinctrl-names = "default";
                    pinctrl-0 = <&sj201_key_pins>;
                    status = "okay";
                    debounce-interval = <50>;

                    button_volume_up: button@22 {
                        gpios = <&gpio 22 1>;
                        linux,code = <115>; // KEY_VOLUMEUP
                        label = "Volume Up";
                    };

                    button_volume_down: button@23 {
                        gpios = <&gpio 23 1>;
                        linux,code = <114>; // KEY_VOLUMEDOWN
                        label = "Volume Down";
                    };

                    button_wake_up: button@24 {
                        gpios = <&gpio 24 1>;
                        linux,code = <582>; // KEY_VOICECOMMAND
                        label = "Wake Up";
                        gpio-key,wakeup;
                    };

                    switch_mic_mute: button@25 {
                        gpios = <&gpio 25 0>;
                        linux,code = <248>; // KEY_MICMUTE
                        label = "Microphone Mute";
                    };
            };
        };
    };
};