* Allwinner A10 I2S controller

The I2S bus (Inter-IC sound bus) is a serial link for digital
audio data transfer between devices in the system.

Required properties:

- compatible: should be one of the following:
   - "allwinner,sun4i-a10-i2s"
   - "allwinner,sun6i-a31-i2s"
- reg: physical base address of the controller and length of memory mapped
  region.
- interrupts: should contain the I2S interrupt.
- dmas: DMA specifiers for tx and rx dma. See the DMA client binding,
	Documentation/devicetree/bindings/dma/dma.txt
- dma-names: should include "tx" and "rx".
- clocks: a list of phandle + clock-specifer pairs, one for each entry in clock-names.
- clock-names: should contain the following:
   - "apb" : clock for the I2S bus interface
   - "mod" : module clock for the I2S controller
- #sound-dai-cells : Must be equal to 0

Required properties for the following compatibles:
	- "allwinner,sun6i-a31-i2s"
- resets: phandle to the reset line for this codec

Example:

i2s0: i2s@01c22400 {
	#sound-dai-cells = <0>;
	compatible = "allwinner,sun4i-a10-i2s";
	reg = <0x01c22400 0x400>;
	interrupts = <GIC_SPI 16 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&apb0_gates 3>, <&i2s0_clk>;
	clock-names = "apb", "mod";
	dmas = <&dma SUN4I_DMA_NORMAL 3>,
	       <&dma SUN4I_DMA_NORMAL 3>;
	dma-names = "rx", "tx";
};