[PATCH v2 3/5] dt-bindings: phy: qcom,sc8280xp-qmp-usb43dp-phy: Document static lanes mapping

[Neil Armstrong]

The QMP USB3/DP Combo PHY hosts an USB3 phy and a DP PHY on top
of a combo glue to route either lanes to the 4 shared physical lanes.

The routing of the lanes can be:
- 2 DP + 2 USB3
- 4 DP
- 2 USB3

The layout of the lanes was designed to be mapped and swapped
related to the USB-C Power Delivery negociation, so it supports
a finite set of mappings inherited by the USB-C Altmode layouts.

Nevertheless those QMP Comby PHY can be statically used to
drive a DisplayPort connector, DP->HDMI bridge, USB3 A Connector,
etc... without an USB-C connector and no PD events.

Add a property that documents the static lanes mapping to
each underlying PHY to allow supporting boards directly
connecting USB3 and DisplayPort lanes to the QMP Combo
lanes.

Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
---
 .../phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml         | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
index c8bc512df08b5694c8599f475de78679a4438449..12511a462bc6245e0b82726d053d8605148c5047 100644
--- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
+++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
@@ -76,6 +76,35 @@ properties:
   mode-switch: true
   orientation-switch: true
 
+  qcom,static-lanes-mapping:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 4
+    items:
+      enum:
+        - 0 # Unconnected (PHY_NONE)
+        - 4 # USB3 (PHY_TYPE_USB3)
+        - 6 # DisplayPort (PHY_TYPE_DP)
+    description:
+      Describes the static mapping of the Combo PHY lanes, when not used
+      a in a Type-C dynamic setup using USB-C PD Events to change the mapping.
+      The 4 lanes can either routed to the underlying DP PHY or the USB3 PHY.
+      Only 2 of the lanes can be connected to the USB3 PHY, but the 4 lanes can
+      be connected to the DP PHY.
+      The numbers corresponds to the PHY Type the lanes are connected to.
+      The possible combinations are
+        <0 0 0 0> when none are connected
+        <4 4 0 6> USB3 and DP single lane
+        <4 4 6 6> USB3 and DP
+        <6 6 4 4> DP and USB3
+        <6 0 4 4> DP and USB3 single lane
+        <4 4 0 0> USB3 Only
+        <0 0 4 4> USB3 Only
+        <6 0 0 0> DP single lane
+        <0 0 0 6> DP single lane
+        <6 6 0 0> DP 2 lanes
+        <0 0 6 6> DP 2 lanes
+        <6 6 6 6> DP 4 lanes
+
   ports:
     $ref: /schemas/graph.yaml#/properties/ports
     properties:

-- 
2.34.1