a_test.overlay

#include <dt-bindings/zmk/matrix_transform.h>

/{
    chosen {
        zephyr,display = &oled;
        zmk,kscan = &kscan0;
        zmk,matrix_transform = &default_transform;
    };

    encoder_1: encoder_1 {
        compatible = "alps,ec11";
        label = "Encoder 1";
        a-gpios = <&pro_micro 9 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
        b-gpios = <&pro_micro 8 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
        resolution = <2>;
        status = "okay";
    };

    kscan0: kscan {
        compatible = "zmk,kscan-gpio-matrix";
        label = "KSCAN";
        diode-direction = "col2row";

        row-gpios = <&pro_micro 4 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>,
                   <&pro_micro 5 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>,
                   <&pro_micro 6 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;

        col-gpios = <&pro_micro 7 GPIO_ACTIVE_HIGH>,
                   <&pro_micro 8 GPIO_ACTIVE_HIGH>,
                   <&pro_micro 9 GPIO_ACTIVE_HIGH>;
    };

    default_transform: keymap_transform_0 {
        compatible = "zmk,matrix-transform";
        rows = <3>;
        columns = <3>;

        map = <
        RC(0,0)    RC(0,1)    RC(0,2)
        RC(0,1)    RC(1,1)    RC(1,2)
        RC(0,2)    RC(2,1)    RC(2,2)
        >;
    };

};

&pro_micro_i2c {
    status = "okay";

    oled: ssd1306@3c {
        compatible = "solomon,ssd1306fb";
        reg = <0x3c>;
        label = "DISPLAY";
        width = <128>;
        height = <32>;
        segment-offset = <0>;
        page-offset = <0>;
        display-offset = <0>;
        multiplex-ratio = <31>;
        com-sequential;
        prechargep = <0x22>;
    };
};