dt-bindings:iio:adc:envelope-detector: txt to yaml conversion.

Straight forward format conversion.  The example in here is fun in
that it has 2 separate provider / consumer pairs.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20201031181242.742301-5-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/envelope-detector.txt

-Bindings for ADC envelope detector using a DAC and a comparator
-
-The DAC is used to find the peak level of an alternating voltage input
-signal by a binary search using the output of a comparator wired to
-an interrupt pin. Like so:
-                          _
-                         | \
-    input +------>-------|+ \
-                         |   \
-           .-------.     |    }---.
-           |       |     |   /    |
-           |    dac|-->--|- /     |
-           |       |     |_/      |
-           |       |              |
-           |       |              |
-           |    irq|------<-------'
-           |       |
-           '-------'
-
-Required properties:
-- compatible: Should be "axentia,tse850-envelope-detector"
-- io-channels: Channel node of the dac to be used for comparator input.
-- io-channel-names: Should be "dac".
-- interrupt specification for one client interrupt,
-  see ../../interrupt-controller/interrupts.txt for details.
-- interrupt-names: Should be "comp".
-
-Example:
-
-	&i2c {
-		dpot: mcp4651-104@28 {
-			compatible = "microchip,mcp4651-104";
-			reg = <0x28>;
-			#io-channel-cells = <1>;
-		};
-	};
-
-	dac: dac {
-		compatible = "dpot-dac";
-		vref-supply = <&reg_3v3>;
-		io-channels = <&dpot 0>;
-		io-channel-names = "dpot";
-		#io-channel-cells = <1>;
-	};
-
-	envelope-detector {
-		compatible = "axentia,tse850-envelope-detector";
-		io-channels = <&dac 0>;
-		io-channel-names = "dac";
-
-		interrupt-parent = <&gpio>;
-		interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
-		interrupt-names = "comp";
-	};

Documentation/devicetree/bindings/iio/adc/envelope-detector.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/envelope-detector.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ADC envelope detector using a DAC and a comparator
+
+maintainers:
+  - Peter Rosin <peda@axentia.se>
+
+description: |
+  The DAC is used to find the peak level of an alternating voltage input
+  signal by a binary search using the output of a comparator wired to
+  an interrupt pin. Like so:
+                          _
+                         | \
+    input +------>-------|+ \
+                         |   \
+           .-------.     |    }---.
+           |       |     |   /    |
+           |    dac|-->--|- /     |
+           |       |     |_/      |
+           |       |              |
+           |       |              |
+           |    irq|------<-------'
+           |       |
+           '-------'
+
+properties:
+  compatible:
+    const: axentia,tse850-envelope-detector
+
+  io-channels:
+    maxItems: 1
+    description: Channel node of the dac to be used for comparator input.
+
+  io-channel-names:
+    const: dac
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-names:
+    const: comp
+
+required:
+  - compatible
+  - io-channels
+  - io-channel-names
+  - interrupts
+  - interrupt-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        dpot: dpot@28 {
+            compatible = "microchip,mcp4651-104";
+            reg = <0x28>;
+            #io-channel-cells = <1>;
+        };
+    };
+
+    dac: dac {
+        compatible = "dpot-dac";
+        vref-supply = <&reg_3v3>;
+        io-channels = <&dpot 0>;
+        io-channel-names = "dpot";
+        #io-channel-cells = <1>;
+    };
+
+    envelope-detector {
+        compatible = "axentia,tse850-envelope-detector";
+        io-channels = <&dac 0>;
+        io-channel-names = "dac";
+
+        interrupt-parent = <&gpio>;
+        interrupts = <3 IRQ_TYPE_EDGE_FALLING>;
+        interrupt-names = "comp";
+    };
+...