1. 根目录:
2. Documentation
3. devicetree
4. bindings
5. sound
6. fsl,asrc.txt

Freescale Asynchronous Sample Rate Converter (ASRC) Controller

The Asynchronous Sample Rate Converter (ASRC) converts the sampling rate of a
signal associated with an input clock into a signal associated with a different
output clock. The driver currently works as a Front End of DPCM with other Back
Ends Audio controller such as ESAI, SSI and SAI. It has three pairs to support
three substreams within totally 10 channels.

Required properties:

  - compatible		: Contains "fsl,imx35-asrc" or "fsl,imx53-asrc".

  - reg			: Offset and length of the register set for the device.

  - interrupts		: Contains the spdif interrupt.

  - dmas		: Generic dma devicetree binding as described in
			  Documentation/devicetree/bindings/dma/dma.txt.

  - dma-names		: Contains "rxa", "rxb", "rxc", "txa", "txb" and "txc".

  - clocks		: Contains an entry for each entry in clock-names.

  - clock-names		: Contains the following entries
	"mem"		  Peripheral access clock to access registers.
	"ipg"		  Peripheral clock to driver module.
	"asrck_<0-f>"	  Clock sources for input and output clock.

   - big-endian		: If this property is absent, the little endian mode
			  will be in use as default. Otherwise, the big endian
			  mode will be in use for all the device registers.

   - fsl,asrc-rate	: Defines a mutual sample rate used by DPCM Back Ends.

   - fsl,asrc-width	: Defines a mutual sample width used by DPCM Back Ends.

Example:

asrc: asrc@02034000 {
	compatible = "fsl,imx53-asrc";
	reg = <0x02034000 0x4000>;
	interrupts = <0 50 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&clks 107>, <&clks 107>, <&clks 0>,
	       <&clks 0>, <&clks 0>, <&clks 0>, <&clks 0>,
	       <&clks 0>, <&clks 0>, <&clks 0>, <&clks 0>,
	       <&clks 0>, <&clks 0>, <&clks 0>, <&clks 0>,
	       <&clks 107>, <&clks 0>, <&clks 0>;
	clock-names = "mem", "ipg", "asrck0",
		"asrck_1", "asrck_2", "asrck_3", "asrck_4",
		"asrck_5", "asrck_6", "asrck_7", "asrck_8",
		"asrck_9", "asrck_a", "asrck_b", "asrck_c",
		"asrck_d", "asrck_e", "asrck_f";
	dmas = <&sdma 17 23 1>, <&sdma 18 23 1>, <&sdma 19 23 1>,
	     <&sdma 20 23 1>, <&sdma 21 23 1>, <&sdma 22 23 1>;
	dma-names = "rxa", "rxb", "rxc",
		"txa", "txb", "txc";
	fsl,asrc-rate  = <48000>;
	fsl,asrc-width = <16>;
	status = "okay";
};