dt-bindings: watchdog: sp-805: Convert to Json-schema

Convert the ARM SP-805 watchdog IP DT binding over to Json-schema.

A straight-forward conversion, but the requirement for providing two
clocks got strengthened from "should" to "must".
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20200909105046.160991-1-andre.przywara@arm.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/watchdog/arm,sp805.txt

-ARM AMBA Primecell SP805 Watchdog
-
-SP805 WDT is a ARM Primecell Peripheral and has a standard-id register that
-can be used to identify the peripheral type, vendor, and revision.
-This value can be used for driver matching.
-
-As SP805 WDT is a primecell IP, it follows the base bindings specified in
-'arm/primecell.txt'
-
-Required properties:
-- compatible:  Should be "arm,sp805" & "arm,primecell"
-- reg:         Should contain location and length for watchdog timer register
-- clocks:      Clocks driving the watchdog timer hardware. This list should be
-               2 clocks. With 2 clocks, the order is wdog_clk, apb_pclk
-               wdog_clk can be equal to or be a sub-multiple of the apb_pclk
-               frequency
-- clock-names: Shall be "wdog_clk" for first clock and "apb_pclk" for the
-               second one
-
-Optional properties:
-- interrupts:  Should specify WDT interrupt number
-- timeout-sec: Should specify default WDT timeout in seconds. If unset, the
-               default timeout is determined by the driver
-
-Example:
-	watchdog@66090000 {
-		compatible = "arm,sp805", "arm,primecell";
-		reg = <0x66090000 0x1000>;
-		interrupts = <GIC_SPI 406 IRQ_TYPE_LEVEL_HIGH>;
-		clocks = <&wdt_clk>, <&apb_pclk>;
-		clock-names = "wdog_clk", "apb_pclk";
-	};

Documentation/devicetree/bindings/watchdog/arm,sp805.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/arm,sp805.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM AMBA Primecell SP805 Watchdog
+
+maintainers:
+  - Viresh Kumar <vireshk@kernel.org>
+
+description: |+
+  The Arm SP805 IP implements a watchdog device, which triggers an interrupt
+  after a configurable time period. If that interrupt has not been serviced
+  when the next interrupt would be triggered, the reset signal is asserted.
+
+allOf:
+  - $ref: /schemas/watchdog/watchdog.yaml#
+
+# Need a custom select here or 'arm,primecell' will match on lots of nodes
+select:
+  properties:
+    compatible:
+      contains:
+        const: arm,sp805
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: arm,sp805
+      - const: arm,primecell
+
+  interrupts:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    description: |
+      Clocks driving the watchdog timer hardware. The first clock is used
+      for the actual watchdog counter. The second clock drives the register
+      interface.
+    minItems: 2
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: wdog_clk
+      - const: apb_pclk
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    watchdog@66090000 {
+        compatible = "arm,sp805", "arm,primecell";
+        reg = <0x66090000 0x1000>;
+        interrupts = <GIC_SPI 406 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&wdt_clk>, <&apb_pclk>;
+        clock-names = "wdog_clk", "apb_pclk";
+    };