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 non-RGMII ports 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>
---
 .../devicetree/bindings/net/dsa/lantiq,gswip.yaml          | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
index ed274bfb8d49..48641c27da10 100644
--- a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
@@ -13,6 +13,8 @@ allOf:
         patternProperties:
           "^port@[0-6]$":
             type: object
+            allOf:
+              - $ref: /schemas/net/dsa/dsa-port.yaml#
             properties:
               tx-internal-delay-ps:
                 enum: [0, 500, 1000, 1500, 2000, 2500, 3000, 3500]
@@ -26,6 +28,11 @@ allOf:
                 description:
                   RGMII RX Clock Delay defined in pico seconds.
                   The delay lines adjust the MII clock vs. data timing.
+              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>
-- 
2.51.0