* Universal Asynchronous Receiver/Transmitter (UART)

- compatible: "rockchip,rk_serial"

  Compatibility with all rk28xx rk29xx rk30xx rk31xx SOCs.

- reg: The base address of the UART register bank.

- interrupts: A single interrupt specifier.

- id: port line, determine the ttySx
 
- use-dma-rx: enable dma receive

- use-dma-tx: enable dma tramsmit

Example:
uart0: serial@10124000 {
		compatible = "rockchip,rk_serial";
		reg = <0x10124000 0x100>;
		interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
		clock-frequency = <24000000>;
		id = <0>;
		use-dma-rx;
		use-dma-tx;
		status = "disabled";
	};