dt-bindings: net: Add network-class schema for mac-address properties

The ethernet-controller schema specifies "mac-address" and
"local-mac-address" but other network devices such as wireless network
adapters use mac addresses as well.
The Devicetree Specification, Release v0.3 specifies in section 4.3.1
a generic "Network Class Binding" with "address-bits", "mac-address",
"local-mac-address" and "max-frame-size". This schema specifies the
"address-bits" property and moves the remaining properties over from
the ethernet-controller.yaml schema.

The "max-frame-size" property is used to describe the maximal payload
size despite its name. Keep the description from ethernet-controller
specifying this property as MTU. The contradictory description in the
Devicetree Specification is ignored.

Signed-off-by: Janne Grunau <[e-mail]>
Signed-off-by: David Heidelberg <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

Documentation/devicetree/bindings/net/ethernet-controller.yaml

···
   label:
     description: Human readable label on a port of a box.
 
-  local-mac-address:
-    description:
-      Specifies the MAC address that was assigned to the network device.
-    $ref: /schemas/types.yaml#/definitions/uint8-array
-    minItems: 6
-    maxItems: 6
-
-  mac-address:
-    description:
-      Specifies the MAC address that was last used by the boot
-      program; should be used in cases where the MAC address assigned
-      to the device by the boot program is different from the
-      local-mac-address property.
-    $ref: /schemas/types.yaml#/definitions/uint8-array
-    minItems: 6
-    maxItems: 6
-
-  max-frame-size:
-    $ref: /schemas/types.yaml#/definitions/uint32
-    description:
-      Maximum transfer unit (IEEE defined MTU), rather than the
-      maximum frame size (there\'s contradiction in the Devicetree
-      Specification).
-
   max-speed:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
···
   pcs-handle-names: [pcs-handle]
 
 allOf:
+  - $ref: /schemas/net/network-class.yaml#
   - if:
       properties:
         phy-mode:

Documentation/devicetree/bindings/net/network-class.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/network-class.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Network Class Common Properties
+
+maintainers:
+  - Devicetree Specification Mailing List <[e-mail]>
+
+properties:
+  address-bits:
+    description:
+      Specifies number of address bits required to address the device
+      described by this node, e.g. size of the MAC address.
+    default: 48
+    const: 48
+
+  local-mac-address:
+    description:
+      Specifies MAC address that was assigned to the network device described by
+      the node containing this property.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    minItems: 6
+    maxItems: 6
+
+  mac-address:
+    description:
+      Specifies the MAC address that was last used by the boot program. This
+      property should be used in cases where the MAC address assigned to the
+      device by the boot program is different from the
+      local-mac-address property. This property shall be used only if the value
+      differs from local-mac-address property value.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+    minItems: 6
+    maxItems: 6
+
+  max-frame-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Maximum transfer unit (IEEE defined MTU), rather than the
+      maximum frame size (there\'s contradiction in the Devicetree
+      Specification).
+
+additionalProperties: true