[PATCH v5 1/9] dt-bindings: soc: qcom: eud: Add per-path child nodes for UTMI routing

[Elson Serrao <elson.serrao@oss.qualcomm.com>]

The Qualcomm Embedded USB Debugger (EUD) can intercept one or two
High-Speed UTMI paths depending on the SoC. For example, SC7280 supports
EUD on the primary UTMI path only, while SM8350 supports EUD on both
primary and secondary UTMI paths.

Each UTMI path connects an independent USB controller/connector pair and
forms its own role-switch domain. EUD routes traffic based on USB role.
In device role the debug hub is inserted, while in host role it is
bypassed.

The existing binding models EUD using a flattened ports representation.
While sufficient for fixed device-role configurations, it cannot naturally
associate a controller, connector, and role switch with a specific
EUD-routable path. This is problematic for role-switch capable ports and
becomes more pronounced on SoCs with multiple paths. In such cases, each
path forms an independent role-switch domain and requires per-path role
awareness.

Model each UTMI path as a separate child node with its own OF graph. Add
an SM8350 compatible for dual-path EUD topologies while retaining the
legacy ports representation for backward compatibility.

Signed-off-by: Elson Serrao <elson.serrao@oss.qualcomm.com>
---
 .../bindings/soc/qcom/qcom,eud.yaml           | 128 +++++++++++++++++-
 1 file changed, 127 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
index 84218636c0d8..6fef958487c8 100644
--- a/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
+++ b/Documentation/devicetree/bindings/soc/qcom/qcom,eud.yaml
@@ -18,6 +18,7 @@ properties:
     items:
       - enum:
           - qcom,sc7280-eud
+          - qcom,sm8350-eud
       - const: qcom,eud
 
   reg:
@@ -45,10 +46,82 @@ properties:
         $ref: /schemas/graph.yaml#/properties/port
         description: This port is to be attached to the type C connector.
 
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^eud-path@[0-1]$":
+    type: object
+    description:
+      Represents one High-Speed UTMI path that EUD intercepts. Use eud-path nodes
+      to associate role-switching behavior with specific port connections, allowing
+      EUD to manage role transitions independently for each UTMI path.
+
+    properties:
+      reg:
+        maxItems: 1
+        description: Path number
+
+      usb-role-switch:
+        type: boolean
+        description:
+          Indicates that EUD relays USB role-switch events for this path and
+          performs role-dependent UTMI routing accordingly. In device role,
+          the EUD hub is inserted into this path to enable debug
+          functionality. In host role, the EUD hub is bypassed and UTMI
+          traffic flows directly between the PHY and the USB controller.
+
+      ports:
+        $ref: /schemas/graph.yaml#/properties/ports
+        description:
+          These ports are to be attached to the endpoint of the USB controller node
+          and USB connector node.
+
+        properties:
+          port@0:
+            $ref: /schemas/graph.yaml#/properties/port
+            description: This port is to be attached to the USB controller.
+
+          port@1:
+            $ref: /schemas/graph.yaml#/properties/port
+            description: This port is to be attached to the USB connector.
+
+    required:
+      - reg
+      - ports
+
+    additionalProperties: false
+
 required:
   - compatible
   - reg
-  - ports
+
+oneOf:
+  - required:
+      - ports
+  - allOf:
+      - if:
+          properties:
+            compatible:
+              contains:
+                const: qcom,sc7280-eud
+        then:
+          required:
+            - eud-path@0
+          properties:
+            eud-path@1: false
+      - if:
+          properties:
+            compatible:
+              contains:
+                const: qcom,sm8350-eud
+        then:
+          required:
+            - eud-path@0
+            - eud-path@1
 
 additionalProperties: false
 
@@ -77,3 +150,56 @@ examples:
             };
         };
     };
+  - |
+    eud@88e0000 {
+        compatible = "qcom,sm8350-eud", "qcom,eud";
+        reg = <0x88e0000 0x2000>,
+              <0x88e2000 0x1000>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        eud-path@0 {
+            reg = <0>;
+            usb-role-switch;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                port@0 {
+                    reg = <0>;
+                    eud_usb0: endpoint {
+                        remote-endpoint = <&usb_1_dwc3_hs>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    eud_con0: endpoint {
+                        remote-endpoint = <&pmic_glink_hs_in>;
+                    };
+                };
+            };
+        };
+
+        eud-path@1 {
+            reg = <1>;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                port@0 {
+                    reg = <0>;
+                    eud_usb1: endpoint {
+                        remote-endpoint = <&usb_2_dwc3_hs>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+                    eud_con1: endpoint {
+                        remote-endpoint = <&conn_2_hs_in>;
+                    };
+                };
+            };
+        };
+    };
-- 
2.34.1