MT7621(How to modify DTS file for adding a new SPI device)

Hi, Good day,
I have a board that it's SOC which is MT7621 interface with LE9622(https://www.microchip.com/en-us/product/le9622) through SPI interface.
I should mention that the only SPI interface of MT7621 is handling the SPI Flash and I am going to use the same interface for LE9622 but with different chipset.
For adding the child node under the SPI interface of MT7621 device tree file , I am trying to define a child node and define the LE9622 there.

My problem is that I do not find any information about LE9622 on the device tree bindings directly of kernel to understand how to define the child node.
Does any one know where I can find information about LE9622 driver under linux kernel?
openwrt/build_dir/target-mipsel_24kc_musl/linux-ramips_mt7621/linux-5.15.142/Documentation/devicetree/bindings

Can anybody help me to add child node in device tree for LE9622?
My device tree file is as bellowing:
/ {
compatible = "meisam,7621a-evb", "mediatek,mt7621-soc";
model = "MAM-7621A board";

keys {
	compatible = "gpio-keys";

	reset {
		label = "reset";
		gpios = <&gpio 18 GPIO_ACTIVE_HIGH>;
		linux,code = <KEY_RESTART>;
	};
};

};

&spi0 {
status = "okay";

flash@0 {
	compatible = "jedec,spi-nor";
	reg = <0>;
	spi-max-frequency = <44000000>;
	broken-flash-reset;

	partitions {
		compatible = "fixed-partitions";
		#address-cells = <1>;
		#size-cells = <1>;

		partition@0 {
			label = "u-boot";
			reg = <0x0 0x30000>;
			read-only;
		};

		partition@30000 {
			label = "u-boot-env";
			reg = <0x30000 0x10000>;
			read-only;
		};

		factory: partition@40000 {
			label = "factory";
			reg = <0x40000 0x10000>;
			read-only;

			nvmem-layout {
				compatible = "fixed-layout";
				#address-cells = <1>;
				#size-cells = <1>;

				eeprom_factory_8000: eeprom@8000 {
					reg = <0x8000 0x200>;
				};
			};
		};

		partition@50000 {
			compatible = "denx,uimage";
			label = "firmware";
			reg = <0x50000 0x1fb0000>;
		};
	};
};

};

Best Regards,
Meisam