dt-bindings:iio:adc:ti,palmas-gpadc: txt to yaml format conversion.

Simple conversion of the binding doc for this subnode of the palmas
PMIC.
Given age of driver and lack interaction with original authors,
I've guessed at Tony for a maintainer on this one.  Tony, if you
are happy with that great, otherwise I can default back to myself.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20201031184854.745828-35-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/palmas-gpadc.txt

-* Palmas general purpose ADC IP block devicetree bindings
-
-Channels list:
-	0 battery type
-	1 battery temp NTC (optional current source)
-	2 GP
-	3 temp (with ext. diode, optional current source)
-	4 GP
-	5 GP
-	6 VBAT_SENSE
-	7 VCC_SENSE
-	8 Backup Battery voltage
-	9 external charger (VCHG)
-	10 VBUS
-	11 DC-DC current probe (how does this work?)
-	12 internal die temp
-	13 internal die temp
-	14 USB ID pin voltage
-	15 test network
-
-Required properties:
-- compatible : Must be "ti,palmas-gpadc".
-- #io-channel-cells: Should be set to <1>.
-
-Optional sub-nodes:
-ti,channel0-current-microamp: Channel 0 current in uA.
-	Values are rounded to derive 0uA, 5uA, 15uA, 20uA.
-ti,channel3-current-microamp: Channel 3 current in uA.
-	Values are rounded to derive 0uA, 10uA, 400uA, 800uA.
-ti,enable-extended-delay: Enable extended delay.
-
-Example:
-
-pmic {
-	compatible = "ti,twl6035-pmic", "ti,palmas-pmic";
-	...
-	gpadc {
-		compatible = "ti,palmas-gpadc";
-		interrupts = <18 0
-			      16 0
-			      17 0>;
-		#io-channel-cells = <1>;
-		ti,channel0-current-microamp = <5>;
-		ti,channel3-current-microamp = <10>;
-		};
-	};
-	...
-};

Documentation/devicetree/bindings/iio/adc/ti,palmas-gpadc.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,palmas-gpadc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Palmas general purpose ADC IP block devicetree bindings
+
+maintainers:
+  - Tony Lindgren <tony@atomide.com>
+
+description: |
+  This ADC is often used to provide channels via the io-channels
+  consumer framework.
+  Channels list:
+    0 battery type
+    1 battery temp NTC (optional current source)
+    2 GP
+    3 temp (with ext. diode, optional current source)
+    4 GP
+    5 GP
+    6 VBAT_SENSE
+    7 VCC_SENSE
+    8 Backup Battery voltage
+    9 external charger (VCHG)
+    10 VBUS
+    11 DC-DC current probe (how does this work?)
+    12 internal die temp
+    13 internal die temp
+    14 USB ID pin voltage
+    15 test network
+
+properties:
+  compatible:
+    const: ti,palmas-gpadc
+
+  interrupts:
+    minItems: 1
+    maxItems: 3
+
+  "#io-channel-cells":
+    const: 1
+
+  ti,channel0-current-microamp:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Channel 0 current in uA.
+    enum:
+      - 0
+      - 5
+      - 15
+      - 20
+
+  ti,channel3-current-microamp:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Channel 3 current in uA.
+    enum:
+      - 0
+      - 10
+      - 400
+      - 800
+
+  ti,enable-extended-delay:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: Enable extended delay.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - "#io-channel-cells"
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8183-clk.h>
+    pmic {
+        compatible = "ti,twl6035-pmic", "ti,palmas-pmic";
+        adc {
+            compatible = "ti,palmas-gpadc";
+            interrupts = <18 0
+                          16 0
+                          17 0>;
+            #io-channel-cells = <1>;
+            ti,channel0-current-microamp = <5>;
+            ti,channel3-current-microamp = <10>;
+        };
+    };
+...