[PATCH v2] dt-bindings: net: dsa: microchip: add bit-banged SMI example

[Corentin Guillevic]

KSZ8863 can be configured using I2C, SPI or Microchip SMI. The latter is
similar to MDIO, but uses a different protocol. If the hardware doesn't
support this, SMI bit banging can help. This commit adds an device tree
example that uses the CONFIG_MDIO_GPIO driver for SMI bit banging.

Signed-off-by: Corentin Guillevic <corentin.guillevic@xxxxxxxx>
---
Changes in v2:
- Fix dt_binding_check errors

 .../bindings/net/dsa/microchip,ksz.yaml       | 59 ++++++++++++++++++-
 1 file changed, 58 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml b/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
index 62ca63e8a26f..33a067809ebe 100644
--- a/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
+++ b/Documentation/devicetree/bindings/net/dsa/microchip,ksz.yaml
@@ -241,4 +241,61 @@ examples:
             };
         };
     };
-...
+
+  # KSZ8863 with bit-banged SMI
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    // Ethernet switch connected via SMI to the host, CPU port wired to eth0:
+    ethernet0 {
+        phy-mode = "rmii";
+
+        fixed-link {
+            speed = <100>;
+            full-duplex;
+            pause;
+        };
+    };
+
+    mdio: mdio {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "microchip,mdio-smi0";
+        gpios = <&gpioc 1 GPIO_ACTIVE_HIGH>,
+            <&gpioa 2 GPIO_ACTIVE_HIGH>;
+        status = "okay";
+
+        switch@0 {
+            compatible = "microchip,ksz8863";
+            reg = <0>;
+            reset-gpios = <&gpioa 4 GPIO_ACTIVE_LOW>;
+            status = "okay";
+
+            ethernet-ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                lan1: port@0 {
+                    reg = <0>;
+                    label = "lan1";
+                    phy-mode = "internal";
+                };
+                lan2: port@1 {
+                    reg = <1>;
+                    label = "lan2";
+                    phy-mode = "internal";
+                };
+                port@2 {
+                    reg = <2>;
+                    label = "cpu";
+                    ethernet = <&ethernet0>;
+                    phy-mode = "rmii";
+                    microchip,rmii-clk-internal;
+
+                    fixed-link {
+                        speed = <100>;
+                        full-duplex;
+                    };
+                };
+            };
+        };
+    };
-- 
2.49.0