[PATCH net-next] dt-bindings: net: Document Marvell PHY "marvell,reg-init"

The Marvell PHY driver consumes marvell,reg-init as one or more
<page register mask value> tuples. Define the property so dtbs_check
validates the existing board descriptions.

Existing users have no compatible or just "ethernet-phy-ieee802.3-c22"
so this has to go into the generic ethernet-phy.yaml schema. Marking it
deprecated both for that reason and because opaque register
initialization values are discouraged in DT.

Assisted-by: LLM
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
---
 .../devicetree/bindings/net/ethernet-phy.yaml        | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
index c3ebb3af8b52..336f73f9c43f 100644
--- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml

@@ -269,6 +269,18 @@ properties:
       have to be placed on board. When omitted, the PHYs default will be left as
       is.
 
+  marvell,reg-init:
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    deprecated: true
+    description:
+      Register initialization tuples for Marvell PHYs.
+    items:
+      items:
+        - description: register page
+        - description: register number
+        - description: mask of bits to clear
+        - description: value to apply
+
   leds:
     type: object
 

-- 
2.53.0