[PATCH robh next] dt-bindings: usb: add USB controller port

["Rafał Miłecki" <zajec5@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

USB bindings already allow specifying USB device hard wired to a
specific controller port but they don't allow describing port on its
own.

This fixes:
arch/arm/boot/dts/bcm4708-buffalo-wzr-1750dhp.dt.yaml: usb@23000: port@1: 'compatible' is a required property
        From schema: Documentation/devicetree/bindings/usb/generic-xhci.yaml

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
Please check if I got the $nodename part right. Somehow I don't see any
errors / warnings when using:

something@1 {
	reg = <1>;
};
---
 .../devicetree/bindings/usb/usb-hcd.yaml      |  4 +-
 .../devicetree/bindings/usb/usb-port.yaml     | 39 +++++++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/usb/usb-port.yaml

diff --git a/Documentation/devicetree/bindings/usb/usb-hcd.yaml b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
index 56853c17af66..b0c6a79cad57 100644
--- a/Documentation/devicetree/bindings/usb/usb-hcd.yaml
+++ b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
@@ -33,7 +33,9 @@ patternProperties:
   "^.*@[0-9a-f]{1,2}$":
     description: The hard wired USB devices
     type: object
-    $ref: /usb/usb-device.yaml
+    oneOf:
+      - $ref: /usb/usb-port.yaml
+      - $ref: /usb/usb-device.yaml
 
 additionalProperties: true
 
diff --git a/Documentation/devicetree/bindings/usb/usb-port.yaml b/Documentation/devicetree/bindings/usb/usb-port.yaml
new file mode 100644
index 000000000000..68fe16c8703e
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-port.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/usb-port.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: USB port on USB controller
+
+maintainers:
+  - Rafał Miłecki <rafal@milecki.pl>
+
+description: |
+  This binding describes a single USB controller port that doesn't have any
+  device hard wired.
+
+properties:
+  $nodename:
+    pattern: "^port@[0-9a-f]{1,2}$"
+
+  reg:
+    description: number of USB controller port
+    maxItems: 1
+
+required:
+  - reg
+
+additionalProperties: true
+
+examples:
+  - |
+    usb@11270000 {
+        reg = <0x11270000 0x1000>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        port@1 {
+            reg = <1>;
+        };
+    };
-- 
2.26.2