When the Lynx PCS is deployed on a copper backplane link, it must be
prepared to handle clause 73 autoneg and clause 72 link training, which
it can do using a dedicated AN/LT block. The latter doesn't need to be
described in the device tree, because it is discoverable from the SerDes
lanes.

The media type that is deployed on the link is not discoverable though,
so the introduction of a fsl,backplane-mode boolean property appears
necessary to determine whether the AN/LT block should be employed, or
left bypassed.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: patch is new

 .../devicetree/bindings/net/pcs/fsl,lynx-pcs.yaml | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/pcs/fsl,lynx-pcs.yaml b/Documentation/devicetree/bindings/net/pcs/fsl,lynx-pcs.yaml
index fbedf696c555..40fbcd80ee2a 100644
--- a/Documentation/devicetree/bindings/net/pcs/fsl,lynx-pcs.yaml
+++ b/Documentation/devicetree/bindings/net/pcs/fsl,lynx-pcs.yaml

@@ -16,11 +16,24 @@ description: |
 
 properties:
   compatible:
-    const: fsl,lynx-pcs
+    enum:
+      - fsl,lx2160a-lynx-pcs
+      - fsl,lynx-pcs
 
   reg:
     maxItems: 1
 
+  phys:
+    maxItems: 4
+    description:
+      phandle for the SerDes lanes that act as PMA/PMD layer when the PCS is
+      part of a copper backplane PHY.
+
+  fsl,backplane-mode:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Indicates that the PCS is deployed over a copper backplane link.
+
 required:
   - compatible
   - reg

-- 
2.34.1