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Edge2 Android Device Tree Overlay

We can use DT overlays to enable/disable or change configuration for peripherals without recompiling the DT kernel source code.

Device Reference Table

	Android Version	DT overlays folder	DT overlays list variable	DT overlays config file
Edge2	14.0	/vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlays	fdt_overlays	/vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlay.env
VIM4	11.0	/mnt/vendor/odm_ext/custom/overlays/kvim4.dtb.overlays	fdt_overlays	/mnt/vendor/odm_ext/custom/overlays/kvim4.dtb.overlays/kvim4.dtb.overlay.env

DT-overlays dtbo directory: vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlays

khadas@Khadas:~$ ls vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlays
edge2-io-spi.dtbo

DT-overlays configuration file: vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlay.env

Enable：

$ echo fdt_overlays=edge2-io-spi > /vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlay.env

$ cat rk3588s-khadas-edge2.dtb.overlay.env
fdt_overlays=edge2-io-spi

Disable：

$ echo fdt_overlays= > /vendor/custom/boot/dtb/rockchip/rk3588s-khadas-edge2.dtb.overlay.env

$ cat rk3588s-khadas-edge2.dtb.overlay.env
fdt_overlays=

Basic DT overlay source edge2-io-spi:

/dts-v1/;
/plugin/;
 
/ {
	fragment@0 {
		target = <&spi1>;
 
		__overlay__ {
			status = "disabled";
		};
	};
};

dtc -I dts -O dtb -o edge2-io-spi.dtbo edge2-io-spi.dts

Need reboot board to take effect.