Add support for the maxlinear,rmii-refclk-out boolean property on port
nodes to configure the RMII reference clock to be an output rather than
an input.

This property is only applicable for ports in RMII mode and allows the
switch to provide the reference clock for RMII-connected PHYs instead
of requiring an external clock source.

This corresponds to the driver changes that read this Device Tree
property to configure the RMII clock direction.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
---
v6:
 * switch order of patches, move deviation from
   dsa.yaml#/$defs/ethernet-ports to this patch which actually
   needs it

 .../bindings/net/dsa/lantiq,gswip.yaml         | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
index f3154b19af78..b494f414a3e1 100644
--- a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
@@ -6,8 +6,22 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 
 title: Lantiq GSWIP Ethernet switches
 
-allOf:
-  - $ref: dsa.yaml#/$defs/ethernet-ports
+$ref: dsa.yaml#
+
+patternProperties:
+  "^(ethernet-)?ports$":
+    type: object
+    patternProperties:
+      "^(ethernet-)?port@[0-6]$":
+        $ref: dsa-port.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          maxlinear,rmii-refclk-out:
+            type: boolean
+            description:
+              Configure the RMII reference clock to be a clock output
+              rather than an input. Only applicable for RMII mode.
 
 maintainers:
   - Hauke Mehrtens <hauke@hauke-m.de>
-- 
2.51.2