[PATCH v5 7/7] dt-bindings: usb: add documentation for aspeed usb-vhub

[rentao.bupt@gmail.com <rentao.bupt@gmail.com>]

From: Tao Ren <rentao.bupt@gmail.com>

Add device tree binding documentation for the Aspeed USB 2.0 Virtual HUb
Controller.

Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
---
 Changes in v5:
   - updated maintainer to Ben.
   - refined patch description per Joel's suggestion.
 No change in v2/v3/v4:
   - the patch is added to the patch series since v4.

 .../bindings/usb/aspeed,usb-vhub.yaml         | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/aspeed,usb-vhub.yaml

diff --git a/Documentation/devicetree/bindings/usb/aspeed,usb-vhub.yaml b/Documentation/devicetree/bindings/usb/aspeed,usb-vhub.yaml
new file mode 100644
index 000000000000..b8b1700c2423
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/aspeed,usb-vhub.yaml
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2020 Facebook Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/aspeed,usb-vhub.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ASPEED USB 2.0 Virtual Hub Controller
+
+maintainers:
+  - Benjamin Herrenschmidt <benh@kernel.crashing.org>
+
+description: |+
+  The ASPEED USB 2.0 Virtual Hub Controller implements 1 set of USB Hub
+  register and several sets of Device and Endpoint registers to support
+  the Virtual Hub's downstream USB devices.
+
+  Supported number of devices and endpoints vary depending on hardware
+  revisions. AST2400 and AST2500 Virtual Hub supports 5 downstream devices
+  and 15 generic endpoints, while AST2600 Virtual Hub supports 7 downstream
+  devices and 21 generic endpoints.
+
+properties:
+  compatible:
+    enum:
+      - aspeed,ast2400-usb-vhub
+      - aspeed,ast2500-usb-vhub
+      - aspeed,ast2600-usb-vhub
+
+  reg:
+    maxItems: 1
+    description: Common configuration registers
+
+  clocks:
+    maxItems: 1
+    description: The Virtual Hub Controller clock gate
+
+  interrupts:
+    maxItems: 1
+
+  aspeed,vhub-downstream-ports:
+    description: Number of downstream ports supported by the Virtual Hub
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+
+  aspeed,vhub-generic-endpoints:
+    description: Number of generic endpoints supported by the Virtual Hub
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+  - aspeed,vhub-downstream-ports
+  - aspeed,vhub-generic-endpoints
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/aspeed-clock.h>
+    vhub: usb-vhub at 1e6a0000 {
+            compatible = "aspeed,ast2500-usb-vhub";
+            reg = <0x1e6a0000 0x300>;
+            interrupts = <5>;
+            clocks = <&syscon ASPEED_CLK_GATE_USBPORT1CLK>;
+            pinctrl-names = "default";
+            pinctrl-0 = <&pinctrl_usb2ad_default>;
+    };
-- 
2.17.1