[PATCH] dt-bindings: net: renesas,etheravb: Add MDIO bus reset properties

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

The bindings for Renesas Ethernet AVB are from 2015 and contain some
oddities that are impossible to get right without breaking existing
bindings. One such thing is that the MDIO bus properties that should be
its own node are mixed with the node for the IP for Ethernet AVB.

Instead of a separate node for the MDIO bus,

    avb: ethernet@e6800000 {
            compatible = "renesas,etheravb-r8a7795",
                         "renesas,etheravb-rcar-gen3";
            reg = <0xe6800000 0x800>, <0xe6a00000 0x10000>;

            ...

            phy-handle = <&phy0>;

            mdio {
                #address-cells = <1>;
                #size-cells = <0>;

                phy0: ethernet-phy@0 {
                    ...
                };
            };
    };

The Ethernet AVB mix it in one,

    avb: ethernet@e6800000 {
            compatible = "renesas,etheravb-r8a7795",
                         "renesas,etheravb-rcar-gen3";
            reg = <0xe6800000 0x800>, <0xe6a00000 0x10000>;

            ...

            phy-handle = <&phy0>;

            #address-cells = <1>;
            #size-cells = <0>;

            phy0: ethernet-phy@0 {
                ...
            };
    };

This forces to all MDIO bus properties needed to be described in the
Ethernet AVB bindings directly. However not all MDIO bus properties are
described as they were not needed. This change adds the MDIO bus
properties to reset the MDIO bus in preparation for them being used.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 .../bindings/net/renesas,etheravb.yaml        | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/renesas,etheravb.yaml b/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
index de7ba7f345a9..d87f00a25877 100644
--- a/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
+++ b/Documentation/devicetree/bindings/net/renesas,etheravb.yaml
@@ -93,6 +93,25 @@ properties:
     description: Number of size cells on the MDIO bus.
     const: 0
 
+  reset-gpios:
+    maxItems: 1
+    description:
+      The phandle and specifier for the GPIO that controls the RESET
+      lines of all devices on that MDIO bus.
+
+  reset-delay-us:
+    description:
+      RESET pulse width in microseconds. It applies to all MDIO devices
+      and must therefore be appropriately determined based on all devices
+      requirements (maximum value of all per-device RESET pulse widths).
+
+  reset-post-delay-us:
+    description:
+      Delay after reset deassert in microseconds. It applies to all MDIO
+      devices and it's determined by how fast all devices are ready for
+      communication. This delay happens just before e.g. Ethernet PHY
+      type ID auto detection.
+
   renesas,no-ether-link:
     type: boolean
     description:
-- 
2.44.0