Extend the Lantiq GSWIP device tree binding to also cover MaxLinear
GSW1xx switches which are based on the same hardware IP but connected
via MDIO instead of being memory-mapped.

Add compatible strings for MaxLinear GSW120, GSW125, GSW140, GSW141,
and GSW145 switches and adjust the schema to handle the different
connection methods with conditional properties.

Add MaxLinear GSW125 example showing MDIO-connected configuration.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
v7:
 * drop the addition of 'reg-names' to the list of required properties
   and also don't add it to the existing example

v6:
 * keep properties on top level and use allOf for conditional constraints

v5:
 * drop maxlinear,rx-inverted from example

v4:
 * drop maxlinear,rx-inverted and maxlinear,tx-inverted properties for
   now in favor of upcoming generic properties

v3:
 * add maxlinear,rx-inverted and maxlinear,tx-inverted properties

v2:
 * remove git conflict left-overs which somehow creeped in
 * indent example with 4 spaces instead of tabs

since RFC: no changes

 .../bindings/net/dsa/lantiq,gswip.yaml        | 128 +++++++++++++++++-
 1 file changed, 123 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
index 929f6f8e4534..205b683849a5 100644
--- a/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/lantiq,gswip.yaml
@@ -4,7 +4,12 @@
 $id: http://devicetree.org/schemas/net/dsa/lantiq,gswip.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Lantiq GSWIP Ethernet switches
+title: Lantiq GSWIP and MaxLinear GSW1xx Ethernet switches
+
+description:
+  Lantiq GSWIP and MaxLinear GSW1xx switches share the same hardware IP.
+  Lantiq switches are embedded in SoCs and accessed via memory-mapped I/O,
+  while MaxLinear switches are standalone ICs connected via MDIO.
 
 $ref: dsa.yaml#
 
@@ -17,9 +22,14 @@ properties:
       - lantiq,xrx200-gswip
       - lantiq,xrx300-gswip
       - lantiq,xrx330-gswip
+      - maxlinear,gsw120
+      - maxlinear,gsw125
+      - maxlinear,gsw140
+      - maxlinear,gsw141
+      - maxlinear,gsw145
 
   reg:
-    minItems: 3
+    minItems: 1
     maxItems: 3
 
   reg-names:
@@ -36,9 +46,6 @@ properties:
       compatible:
         const: lantiq,xrx200-mdio
 
-    required:
-      - compatible
-
   gphy-fw:
     type: object
     properties:
@@ -123,6 +130,30 @@ required:
   - compatible
   - reg
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - lantiq,xrx200-gswip
+              - lantiq,xrx300-gswip
+              - lantiq,xrx330-gswip
+    then:
+      properties:
+        reg:
+          minItems: 3
+          maxItems: 3
+        mdio:
+          required:
+            - compatible
+    else:
+      properties:
+        reg:
+          maxItems: 1
+        reg-names: false
+        gphy-fw: false
+
 unevaluatedProperties: false
 
 examples:
@@ -230,3 +261,90 @@ examples:
                     };
             };
     };
+
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    mdio {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        switch@1f {
+            compatible = "maxlinear,gsw125";
+            reg = <0x1f>;
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+                    label = "lan0";
+                    phy-handle = <&switchphy0>;
+                    phy-mode = "internal";
+                };
+
+                port@1 {
+                    reg = <1>;
+                    label = "lan1";
+                    phy-handle = <&switchphy1>;
+                    phy-mode = "internal";
+                };
+
+                port@4 {
+                    reg = <4>;
+                    label = "wan";
+                    phy-mode = "1000base-x";
+                    managed = "in-band-status";
+                };
+
+                port@5 {
+                    reg = <5>;
+                    phy-mode = "rgmii-id";
+                    tx-internal-delay-ps = <2000>;
+                    rx-internal-delay-ps = <2000>;
+                    ethernet = <&eth0>;
+
+                    fixed-link {
+                        speed = <1000>;
+                        full-duplex;
+                    };
+                };
+            };
+
+            mdio {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                switchphy0: switchphy@0 {
+                    reg = <0>;
+
+                    leds {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+
+                        led@0 {
+                            reg = <0>;
+                            color = <LED_COLOR_ID_GREEN>;
+                            function = LED_FUNCTION_LAN;
+                        };
+                    };
+                };
+
+                switchphy1: switchphy@1 {
+                    reg = <1>;
+
+                    leds {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+
+                        led@0 {
+                            reg = <0>;
+                            color = <LED_COLOR_ID_GREEN>;
+                            function = LED_FUNCTION_LAN;
+                        };
+                    };
+                };
+            };
+        };
+    };
-- 
2.51.2