[PATCH 2/3] ASoC: dt-bindings: fsl_easrc: Add document for EASRC

[Shengjiu Wang <shengjiu.wang@nxp.com>]

EASRC (Enhanced Asynchronous Sample Rate Converter) is a new
IP module found on i.MX815.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
 .../devicetree/bindings/sound/fsl,easrc.txt   | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/fsl,easrc.txt

diff --git a/Documentation/devicetree/bindings/sound/fsl,easrc.txt b/Documentation/devicetree/bindings/sound/fsl,easrc.txt
new file mode 100644
index 000000000000..0e8153165e3b
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/fsl,easrc.txt
@@ -0,0 +1,57 @@
+NXP 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 four context to support
+four substreams within totally 32 channels.
+
+Required properties:
+- compatible:                Contains "fsl,imx8mn-easrc".
+
+- reg:                       Offset and length of the register set for the
+			     device.
+
+- interrupts:                Contains the asrc interrupt.
+
+- dmas:                      Generic dma devicetree binding as described in
+		             Documentation/devicetree/bindings/dma/dma.txt.
+
+- dma-names:                 Contains "ctx0_rx", "ctx0_tx",
+				      "ctx1_rx", "ctx1_tx",
+			              "ctx2_rx", "ctx2_tx",
+				      "ctx3_rx", "ctx3_tx".
+
+- clocks:                    Contains an entry for each entry in clock-names.
+
+- clock-names:               "mem" - Peripheral clock to driver module.
+
+- fsl,easrc-ram-script-name: The coefficient table for the filters
+
+- 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:
+
+easrc: easrc@300C0000 {
+	compatible = "fsl,imx8mn-easrc";
+	reg = <0x0 0x300C0000 0x0 0x10000>;
+	interrupts = <GIC_SPI 122 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&clk IMX8MN_CLK_ASRC_ROOT>;
+	clock-names = "mem";
+	dmas = <&sdma2 16 23 0> , <&sdma2 17 23 0>,
+	       <&sdma2 18 23 0> , <&sdma2 19 23 0>,
+	       <&sdma2 20 23 0> , <&sdma2 21 23 0>,
+	       <&sdma2 22 23 0> , <&sdma2 23 23 0>;
+	dma-names = "ctx0_rx", "ctx0_tx",
+		    "ctx1_rx", "ctx1_tx",
+		    "ctx2_rx", "ctx2_tx",
+		    "ctx3_rx", "ctx3_tx";
+	fsl,easrc-ram-script-name = "imx/easrc/easrc-imx8mn.bin";
+	fsl,asrc-rate  = <8000>;
+	fsl,asrc-width = <16>;
+	status = "disabled";
+};
-- 
2.21.0