gpio: Rewrite IXP4xx GPIO bindings in schema

This rewrites the IXP4xx GPIO bindings to use YAML schema,
and adds two new properties to enable fixed clock output on
pins 14 and 15.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Documentation/devicetree/bindings/gpio/intel,ixp4xx-gpio.txt

-Intel IXP4xx XScale Networking Processors GPIO
-
-This GPIO controller is found in the Intel IXP4xx processors.
-It supports 16 GPIO lines.
-
-The interrupt portions of the GPIO controller is hierarchical:
-the synchronous edge detector is part of the GPIO block, but the
-actual enabling/disabling of the interrupt line is done in the
-main IXP4xx interrupt controller which has a 1:1 mapping for
-the first 12 GPIO lines to 12 system interrupts.
-
-The remaining 4 GPIO lines can not be used for receiving
-interrupts.
-
-The interrupt parent of this GPIO controller must be the
-IXP4xx interrupt controller.
-
-Required properties:
-
-- compatible : Should be
-  "intel,ixp4xx-gpio"
-- reg : Should contain registers location and length
-- gpio-controller : marks this as a GPIO controller
-- #gpio-cells : Should be 2, see gpio/gpio.txt
-- interrupt-controller : marks this as an interrupt controller
-- #interrupt-cells : a standard two-cell interrupt, see
-  interrupt-controller/interrupts.txt
-
-Example:
-
-gpio0: gpio@c8004000 {
-	compatible = "intel,ixp4xx-gpio";
-	reg = <0xc8004000 0x1000>;
-	gpio-controller;
-	#gpio-cells = <2>;
-	interrupt-controller;
-	#interrupt-cells = <2>;
-};

Documentation/devicetree/bindings/gpio/intel,ixp4xx-gpio.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/intel,ixp4xx-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Intel IXP4xx XScale Networking Processors GPIO Controller
+
+description: |
+  This GPIO controller is found in the Intel IXP4xx
+  processors. It supports 16 GPIO lines.
+  The interrupt portions of the GPIO controller is hierarchical.
+  The synchronous edge detector is part of the GPIO block, but the
+  actual enabling/disabling of the interrupt line is done in the
+  main IXP4xx interrupt controller which has a 1-to-1 mapping for
+  the first 12 GPIO lines to 12 system interrupts.
+  The remaining 4 GPIO lines can not be used for receiving
+  interrupts.
+  The interrupt parent of this GPIO controller must be the
+  IXP4xx interrupt controller.
+  GPIO 14 and 15 can be used as clock outputs rather than GPIO,
+  and this can be enabled by a special flag.
+
+maintainers:
+  - Linus Walleij <linus.walleij@linaro.org>
+
+properties:
+  compatible:
+    const: intel,ixp4xx-gpio
+
+  reg:
+    maxItems: 1
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+  intel,ixp4xx-gpio14-clkout:
+    description: If defined, enables clock output on GPIO 14
+      instead of GPIO.
+    type: boolean
+
+  intel,ixp4xx-gpio15-clkout:
+    description: If defined, enables clock output on GPIO 15
+      instead of GPIO.
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - "#gpio-cells"
+  - interrupt-controller
+  - "#interrupt-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    gpio@c8004000 {
+        compatible = "intel,ixp4xx-gpio";
+        reg = <0xc8004000 0x1000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+        interrupt-controller;
+        #interrupt-cells = <2>;
+    };

MAINTAINERS

@@ -2215,7 +2215,7 @@ M:	Krzysztof Halasa <khalasa@piap.pl>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/intel-ixp4xx.yaml
-F:	Documentation/devicetree/bindings/gpio/intel,ixp4xx-gpio.txt
+F:	Documentation/devicetree/bindings/gpio/intel,ixp4xx-gpio.yaml
 F:	Documentation/devicetree/bindings/interrupt-controller/intel,ixp4xx-interrupt.yaml
 F:	Documentation/devicetree/bindings/memory-controllers/intel,ixp4xx-expansion*
 F:	Documentation/devicetree/bindings/timer/intel,ixp4xx-timer.yaml