dt-bindings: pps: pps-gpio: Convert to yaml

Convert from pps-gpio.txt to pps-gpio.yaml to allow schema validation.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20230818174159.1680572-1-festevam@gmail.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pps/pps-gpio.txt

-Device-Tree Bindings for a PPS Signal on GPIO
-
-These properties describe a PPS (pulse-per-second) signal connected to
-a GPIO pin.
-
-Required properties:
-- compatible: should be "pps-gpio"
-- gpios: one PPS GPIO in the format described by ../gpio/gpio.txt
-
-Additional required properties for the PPS ECHO functionality:
-- echo-gpios: one PPS ECHO GPIO in the format described by ../gpio/gpio.txt
-- echo-active-ms: duration in ms of the active portion of the echo pulse
-
-Optional properties:
-- assert-falling-edge: when present, assert is indicated by a falling edge
-                       (instead of by a rising edge)
-
-Example:
-	pps {
-		pinctrl-names = "default";
-		pinctrl-0 = <&pinctrl_pps>;
-
-		gpios = <&gpio1 26 GPIO_ACTIVE_HIGH>;
-		assert-falling-edge;
-
-		echo-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
-		echo-active-ms = <100>;
-
-		compatible = "pps-gpio";
-	};

Documentation/devicetree/bindings/pps/pps-gpio.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pps/pps-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PPS Signal via GPIO
+
+maintainers:
+  - Fabio Estevam <festevam@gmail.com>
+
+properties:
+  compatible:
+    const: pps-gpio
+
+  gpios:
+    description: The GPIO that provides the PPS signal.
+    maxItems: 1
+
+  echo-gpios:
+    description: The GPIO that provides the PPS ECHO signal.
+    maxItems: 1
+
+  echo-active-ms:
+    description: Duration in ms of the active portion of the echo pulse.
+
+  assert-falling-edge:
+    description: Indicates a falling edge assert, when present. Rising edge if absent.
+    type: boolean
+
+required:
+  - compatible
+  - gpios
+
+additionalProperties: false
+
+examples:
+  - |
+      #include <dt-bindings/gpio/gpio.h>
+
+      pps {
+          compatible = "pps-gpio";
+          pinctrl-names = "default";
+          pinctrl-0 = <&pinctrl_pps>;
+          gpios = <&gpio1 26 GPIO_ACTIVE_HIGH>;
+          assert-falling-edge;
+          echo-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
+          echo-active-ms = <100>;
+      };