[PATCH RFC 07/12] dt-bindings: usb: mediatek,mtk-xhci: Allow ports for USB connections

[Chen-Yu Tsai]

MediaTek's XHCI implementation supports both USB 2.0 High Speed (HS)
and USB 3.x Super Speed (SS). The block can also be synthesized with
either HS-only capability or HS+SS capability.

For example, on the MT8195, the first two instances support both HS and
SS, while the latter two instances support only HS.

Allow a ports sub-node for describing USB connections. Port 1 is Super
Speed if the controller is SS-capable, otherwise it is High Speed. Port
2 is High Speed if SS-capable. This port mapping scheme directly matches
what the hardware returns in its capability registers.

Signed-off-by: Chen-Yu Tsai <wenst at chromium.org>
---
 .../devicetree/bindings/usb/mediatek,mtk-xhci.yaml  | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
index 75ecce3bdc7a..d6c75bd20b78 100644
--- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
+++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
@@ -184,6 +184,19 @@ properties:
   "#size-cells":
     const: 0
 
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port at 1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Super Speed (SS) data bus if SS-capable;
+          otherwise High Speed (HS) data bus.
+
+      port at 2:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: High Speed (HS) data bus if controller is SS-capable.
+
 patternProperties:
   "@[0-9a-f]{1}$":
     type: object
-- 
2.54.0.563.g4f69b47b94-goog