linux-kernel - [PATCH v2 1/3] dt-bindings: usb: fsa4480: Add data-lanes property to endpoint

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Message-Id: <20231020-fsa4480-swap-v2-1-9a7f9bb59873@fairphone.com>
Date:   Fri, 20 Oct 2023 11:33:18 +0200
From:   Luca Weiss <luca.weiss@...rphone.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>
Cc:     ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        Luca Weiss <luca.weiss@...rphone.com>
Subject: [PATCH v2 1/3] dt-bindings: usb: fsa4480: Add data-lanes property
 to endpoint

Allow specifying data-lanes to reverse the muxing orientation between
AUX+/- and SBU1/2 where necessary by the hardware design.

In the mux there's a switch that needs to be controlled from the OS, and
it either connects AUX+ -> SBU1 and AUX- -> SBU2, or the reverse: AUX+
-> SBU2 and AUX- -> SBU1, depending on the orientation of how the USB-C
connector is plugged in.

With this data-lanes property we can now specify that AUX+ and AUX-
connections are swapped between the SoC and the mux, therefore the OS
needs to consider this and reverse the direction of this switch in the
mux.

_______          _______
      |          |     |
      |-- HP   --|     |
      |-- MIC  --|     |or
SoC   |          | MUX |-- SBU1 --->  To the USB-C
Codec |-- AUX+ --|     |-- SBU2 --->  connected
      |-- AUX- --|     |
______|          |_____|

(thanks to Neil Armstrong for this ASCII art)

Signed-off-by: Luca Weiss <luca.weiss@...rphone.com>
---
 .../devicetree/bindings/usb/fcs,fsa4480.yaml       | 29 +++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
index f6e7a5c1ff0b..86f6d633c2fb 100644
--- a/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
+++ b/Documentation/devicetree/bindings/usb/fcs,fsa4480.yaml
@@ -32,10 +32,37 @@ properties:
     type: boolean
 
   port:
-    $ref: /schemas/graph.yaml#/properties/port
+    $ref: /schemas/graph.yaml#/$defs/port-base
     description:
       A port node to link the FSA4480 to a TypeC controller for the purpose of
       handling altmode muxing and orientation switching.
+    unevaluatedProperties: false
+
+    properties:
+      endpoint:
+        $ref: /schemas/graph.yaml#/$defs/endpoint-base
+        unevaluatedProperties: false
+
+        properties:
+          data-lanes:
+            $ref: /schemas/types.yaml#/definitions/uint32-array
+            description:
+              Specifies how the AUX+/- lines are connected to SBU1/2.
+            oneOf:
+              - items:
+                  - const: 0
+                  - const: 1
+                description: |
+                  Default AUX/SBU layout
+                  - AUX+ connected to SBU2
+                  - AUX- connected to SBU1
+              - items:
+                  - const: 1
+                  - const: 0
+                description: |
+                  Swapped AUX/SBU layout
+                  - AUX+ connected to SBU1
+                  - AUX- connected to SBU2
 
 required:
   - compatible

-- 
2.42.0