[PATCH v4 11/12] ASoC: add bindings for stm32 DFSDM filter

[Arnaud Pouliquen]

Add bindings that describes audio settings to support
Digital Filter for pulse density modulation(PDM) microphone.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
---
V3 -> V4 changes:
	- Update to move on of_graph description.
	- Link to DFSDM IIO bindings.

 .../devicetree/bindings/sound/st,stm32-adfsdm.txt  | 63 ++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/st,stm32-adfsdm.txt

diff --git a/Documentation/devicetree/bindings/sound/st,stm32-adfsdm.txt b/Documentation/devicetree/bindings/sound/st,stm32-adfsdm.txt
new file mode 100644
index 0000000..75e298b
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/st,stm32-adfsdm.txt
@@ -0,0 +1,63 @@
+STMicroelectronics audio DFSDM DT bindings
+
+This driver supports audio PDM microphone capture through Digital Filter format
+Sigma Delta modulators (DFSDM).
+
+Required properties:
+  - compatible: "st,stm32h7-dfsdm-dai".
+
+  - #sound-dai-cells : Must be equal to 0
+
+  - io-channels : phandle to iio dfsdm instance node.
+		[See: ../iio/adc/st,stm32-dfsdm-adc.txt for DFSDM options]
+
+Example of a sound card using audio DFSDM node.
+
+	sound_card {
+		compatible = "audio-graph-card";
+
+		dais = <&cpu_port>;
+	};
+
+	dfsdm: dfsdm at 40017000 {
+		compatible = "st,stm32h7-dfsdm";
+		reg = <0x40017000 0x400>;
+		clocks = <&rcc DFSDM1_CK>;
+		clock-names = "dfsdm";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		dfsdm_adc0: dfsdm-adc at 0 {
+			compatible = "st,stm32-dfsdm-dmic";
+			reg = <0>;
+			interrupts = <110>;
+			dmas = <&dmamux1 101 0x400 0x00>;
+			dma-names = "rx";
+			st,adc-channels = <1>;
+			st,adc-channel-names = "dmic0";
+			st,adc-channel-types = "SPI_R";
+			st,adc-channel-clk-src = "CLKOUT";
+			st,filter-order = <5>;
+		};
+	}
+
+	dfsdm_dai0:dfsdm_dai at 0 {
+		compatible = "st,stm32h7-dfsdm-dai";
+		#sound-dai-cells = <0>;
+		io-channels = <&dfsdm_adc0 0>;
+		cpu_port: port {
+			dfsdm_endpoint: endpoint {
+				remote-endpoint = <&dmic0_endpoint>;
+			};
+		};
+	};
+
+	dmic0: dmic at 0 {
+		compatible = "dmic-codec";
+		#sound-dai-cells = <0>;
+		port {
+			dmic0_endpoint: endpoint {
+				remote-endpoint = <&dfsdm_endpoint>;
+			};
+		};
+	};
-- 
2.7.4