设备树 overlays ?

/dts-v1/;
/plugin/;
/ {
    compatible = "xunlong,orangepi-3-lts,allwinner,sun50i-h6";

    fragment@0 {
        target = <&spi1>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            status = "okay";
            display@0{
                compatible = "sitronix,st7789v_240x240";
                reg = <0>;
                spi-max-frequency = <20000000>;
                dc-gpios = <&pio 3 16 0>;
                reset-gpios = <&pio 3 18 0>;
                rotation = <0>;
            };
        };
    };
};

dtc demo.dts -o demo.dtbo
cp demo.dtbo /boot/dtb/allwinner/overlay/sun50i-h6-demo.dtbo
vim /boot/orangepiEnv.txt 
overlays=demo

目前不知道怎么实现, 但可提高驱动开发效率，不需要重新编译内核。

• 已经明确是 u-boot 先读取 /boot/orangepiEnv.txt 获取要加载的 orangepiEnv 子片段，最后拼接成设备树后再启动内核。
  example , 添加根路径下设备 target-path = "/";