dt-bindings: phy: qcom,snps-eusb2-repeater: Add magic tuning overrides

[ Upstream commit c20b59b2996c89c4f072c3312e6210528a298330 ]

The EUSB2 repeater requires some alterations to its init sequence,
depending on board design.

Add support for making the necessary changes to that sequence to make USB
functional on SM8550-based Xperia 1 V.

They all have lackluster description due to lack of information.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230830-topic-eusb2_override-v2-1-7d8c893d93f6@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Documentation/devicetree/bindings/phy/qcom,snps-eusb2-repeater.yaml

@@ -32,6 +32,27 @@ properties:
 
   vdd3-supply: true
 
+  qcom,tune-usb2-disc-thres:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description: High-Speed disconnect threshold
+    minimum: 0
+    maximum: 7
+    default: 0
+
+  qcom,tune-usb2-amplitude:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description: High-Speed trasmit amplitude
+    minimum: 0
+    maximum: 15
+    default: 8
+
+  qcom,tune-usb2-preem:
+    $ref: /schemas/types.yaml#/definitions/uint8
+    description: High-Speed TX pre-emphasis tuning
+    minimum: 0
+    maximum: 7
+    default: 5
+
 required:
   - compatible
   - reg