dt-bindings: ipmi: Convert ASPEED KCS binding to schema

Given the deprecated binding, improve the ability to detect issues in
the platform devicetrees. Further, a subsequent patch will introduce a
new interrupts property for specifying SerIRQ behaviour, so convert
before we do any further additions.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Zev Weiss <zweiss@equinix.com>
Message-Id: <20210608104757.582199-13-andrew@aj.id.au>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Documentation/devicetree/bindings/ipmi/aspeed,ast2400-kcs-bmc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ipmi/aspeed,ast2400-kcs-bmc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ASPEED BMC KCS Devices
+
+maintainers:
+  - Andrew Jeffery <andrew@aj.id.au>
+
+description: |
+  The Aspeed BMC SoCs typically use the Keyboard-Controller-Style (KCS)
+  interfaces on the LPC bus for in-band IPMI communication with their host.
+
+properties:
+  compatible:
+    oneOf:
+      - description: Channel ID derived from reg
+        items:
+          enum:
+            - aspeed,ast2400-kcs-bmc-v2
+            - aspeed,ast2500-kcs-bmc-v2
+            - aspeed,ast2600-kcs-bmc
+
+      - description: Old-style with explicit channel ID, no reg
+        deprecated: true
+        items:
+          enum:
+            - aspeed,ast2400-kcs-bmc
+            - aspeed,ast2500-kcs-bmc
+
+  interrupts:
+    maxItems: 1
+
+  reg:
+    # maxItems: 3
+    items:
+      - description: IDR register
+      - description: ODR register
+      - description: STR register
+
+  aspeed,lpc-io-reg:
+    $ref: '/schemas/types.yaml#/definitions/uint32-array'
+    minItems: 1
+    maxItems: 2
+    description: |
+      The host CPU LPC IO data and status addresses for the device. For most
+      channels the status address is derived from the data address, but the
+      status address may be optionally provided.
+
+  kcs_chan:
+    deprecated: true
+    $ref: '/schemas/types.yaml#/definitions/uint32'
+    description: The LPC channel number in the controller
+
+  kcs_addr:
+    deprecated: true
+    $ref: '/schemas/types.yaml#/definitions/uint32'
+    description: The host CPU IO map address
+
+required:
+  - compatible
+  - interrupts
+
+additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - aspeed,ast2400-kcs-bmc
+              - aspeed,ast2500-kcs-bmc
+    then:
+      required:
+        - kcs_chan
+        - kcs_addr
+    else:
+      required:
+        - reg
+        - aspeed,lpc-io-reg
+
+examples:
+  - |
+    kcs3: kcs@24 {
+        compatible = "aspeed,ast2600-kcs-bmc";
+        reg = <0x24 0x1>, <0x30 0x1>, <0x3c 0x1>;
+        aspeed,lpc-io-reg = <0xca2>;
+        interrupts = <8>;
+    };

Documentation/devicetree/bindings/ipmi/aspeed-kcs-bmc.txt

-# Aspeed KCS (Keyboard Controller Style) IPMI interface
-
-The Aspeed SOCs (AST2400 and AST2500) are commonly used as BMCs
-(Baseboard Management Controllers) and the KCS interface can be
-used to perform in-band IPMI communication with their host.
-
-## v1
-Required properties:
-- compatible : should be one of
-    "aspeed,ast2400-kcs-bmc"
-    "aspeed,ast2500-kcs-bmc"
-- interrupts : interrupt generated by the controller
-- kcs_chan : The LPC channel number in the controller
-- kcs_addr : The host CPU IO map address
-
-## v2
-Required properties:
-- compatible : should be one of
-    "aspeed,ast2400-kcs-bmc-v2"
-    "aspeed,ast2500-kcs-bmc-v2"
-- reg : The address and size of the IDR, ODR and STR registers
-- interrupts : interrupt generated by the controller
-- aspeed,lpc-io-reg : The host CPU LPC IO address for the device
-
-Example:
-
-    kcs3: kcs@24 {
-        compatible = "aspeed,ast2500-kcs-bmc-v2";
-        reg = <0x24 0x1>, <0x30 0x1>, <0x3c 0x1>;
-        aspeed,lpc-reg = <0xca2>;
-        interrupts = <8>;
-        status = "okay";
-    };