ASoC: davinci-mcbsp: add binding for McBSP

Texas Instruments DaVinci McBSP module

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This binding describes the "Multi-channel Buffered Serial Port" (McBSP)

audio interface found in some TI DaVinci processors like the OMAP-L138 or AM180x.

Required properties:

~~~~~~~~~~~~~~~~~~~~

- compatible :

        "ti,da850-mcbsp" : for DA850, AM180x and OPAM-L138 platforms

- reg : physical base address and length of the controller memory mapped

        region(s).

- reg-names : Should contain:

        * "mpu" for the main registers (required).

        * "dat" for the data FIFO (optional).

- dmas: three element list of DMA controller phandles, DMA request line and

	TC channel ordered triplets.

- dma-names: identifier string for each DMA request line in the dmas property.

	These strings correspond 1:1 with the ordered pairs in dmas. The dma

	identifiers must be "rx" and "tx".

Optional properties:

~~~~~~~~~~~~~~~~~~~~

- interrupts : Interrupt numbers for McBSP

- interrupt-names : Known interrupt names are "rx" and "tx"

- pinctrl-0: Should specify pin control group used for this controller.

- pinctrl-names: Should contain only one value - "default", for more details

        please refer to pinctrl-bindings.txt

Example (AM1808):

~~~~~~~~~~~~~~~~~

mcbsp0: mcbsp@1d10000 {

	compatible = "ti,da850-mcbsp";

	pinctrl-names = "default";

	pinctrl-0 = <&mcbsp0_pins>;

	reg = 	<0x00110000 0x1000>,

		<0x00310000 0x1000>;

	reg-names = "mpu", "dat";

	interrupts = <97 98>;

	interrupts-names = "rx", "tx";

	dmas = <&edma0 3 1

		&edma0 2 1>;

	dma-names = "tx", "rx";

	status = "okay";

};