dt-bindings: gpio: convert gpio-pisosr.txt to yaml format

Covert gpio-pisosr.txt to yaml format.

Additional changes:
- Add ref to spi-peripheral-props.yaml.
- Set ngpios max value to 32.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250522223742.516254-1-Frank.Li@nxp.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

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

@@ -1,34 +0,0 @@
-Generic Parallel-in/Serial-out Shift Register GPIO Driver
-
-This binding describes generic parallel-in/serial-out shift register
-devices that can be used for GPI (General Purpose Input). This includes
-SN74165 serial-out shift registers and the SN65HVS88x series of
-industrial serializers.
-
-Required properties:
- - compatible		: Should be "pisosr-gpio".
- - gpio-controller	: Marks the device node as a GPIO controller.
- - #gpio-cells		: Should be two. For consumer use see gpio.txt.
-
-Optional properties:
- - ngpios		: Number of used GPIO lines (0..n-1), default is 8.
- - load-gpios		: GPIO pin specifier attached to load enable, this
-			  pin is pulsed before reading from the device to
-			  load input pin values into the device.
-
-For other required and optional properties of SPI slave
-nodes please refer to ../spi/spi-bus.txt.
-
-Example:
-
-	gpio@0 {
-		compatible = "ti,sn65hvs882", "pisosr-gpio";
-		gpio-controller;
-		#gpio-cells = <2>;
-
-		load-gpios = <&gpio2 23 GPIO_ACTIVE_LOW>;
-
-		reg = <0>;
-		spi-max-frequency = <1000000>;
-		spi-cpol;
-	};

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

@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/pisosr-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic Parallel-in/Serial-out Shift Register GPIO Driver
+
+description:
+  This binding describes generic parallel-in/serial-out shift register
+  devices that can be used for GPI (General Purpose Input). This includes
+  SN74165 serial-out shift registers and the SN65HVS88x series of
+  industrial serializers.
+
+maintainers:
+  - Frank Li <Frank.Li@nxp.com>
+
+properties:
+  compatible:
+    enum:
+      - pisosr-gpio
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+  ngpios:
+    maximum: 32
+    default: 8
+
+  load-gpios:
+    description:
+      GPIO pin specifier attached to load enable, this
+      pin is pulsed before reading from the device to
+      load input pin values into the device.
+
+  spi-cpol: true
+
+required:
+  - compatible
+  - gpio-controller
+  - '#gpio-cells'
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        gpio@0 {
+            compatible = "pisosr-gpio";
+            reg = <0>;
+            gpio-controller;
+            #gpio-cells = <2>;
+            load-gpios = <&gpio2 23 GPIO_ACTIVE_LOW>;
+            spi-max-frequency = <1000000>;
+            spi-cpol;
+        };
+    };