[PATCH net-next] dt-bindings: net: dsa: make phylink bindings required for CPU/DSA ports

[Vladimir Oltean <vladimir.oltean@nxp.com>]

It is desirable that new DSA drivers are written to expect that all
their ports register with phylink, and not rely on the DSA core's
workarounds to skip this process.

To that end, DSA is being changed to warn existing drivers when such DT
blobs are in use:
https://patchwork.kernel.org/project/netdevbpf/cover/20220729132119.1191227-1-vladimir.oltean@nxp.com/

Introduce another layer of validation in the DSA DT schema, and assert
that CPU and DSA ports must have phylink-related properties present.

Suggested-by: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
I've sent this patch separately because at least right now I don't have
a reason to resend the other 4 patches linked above, and this has no
dependency on those.

 .../devicetree/bindings/net/dsa/dsa-port.yaml | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml b/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
index 09317e16cb5d..a9420302c5d8 100644
--- a/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/dsa-port.yaml
@@ -76,6 +76,28 @@ properties:
 required:
   - reg
 
+if:
+  oneOf:
+    - properties:
+        ethernet:
+          items:
+            $ref: /schemas/types.yaml#/definitions/phandle
+    - properties:
+        link:
+          items:
+            $ref: /schemas/types.yaml#/definitions/phandle-array
+then:
+  allOf:
+  - required:
+    - phy-mode
+  - oneOf:
+    - required:
+      - fixed-link
+    - required:
+      - phy-handle
+    - required:
+      - managed
+
 additionalProperties: true
 
 ...
-- 
2.34.1