Merge branch 'Enable-Fiber-on-DP83822-PHY'

Dan Murphy says:

====================
Enable Fiber on DP83822 PHY

The DP83822 Ethernet PHY has the ability to connect via a Fiber port.  The
derivative PHYs DP83825 and DP83826 do not have this ability. In fiber mode
the DP83822 disables auto negotiation and has a fixed 100Mbps speed with
support for full or half duplex modes.

A devicetree binding was added to set the signal polarity for the fiber
connection.  This property is only applicable if the FX_EN strap is set in
hardware other wise the signal loss detection is disabled on the PHY.

If the FX_EN is not strapped the device can be configured to run in fiber mode
via the device tree. All be it the PHY will not perform signal loss detection.

v2 review from a long time ago can be found here - https://lore.kernel.org/patchwork/patch/1270958/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ti,dp83822.yaml

@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
+# Copyright (C) 2020 Texas Instruments Incorporated
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/net/ti,dp83822.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: TI DP83822 ethernet PHY
+
+maintainers:
+  - Dan Murphy <dmurphy@ti.com>
+
+description: |
+  The DP83822 is a low-power, single-port, 10/100 Mbps Ethernet PHY. It
+  provides all of the physical layer functions needed to transmit and receive
+  data over standard, twisted-pair cables or to connect to an external,
+  fiber-optic transceiver. Additionally, the DP83822 provides flexibility to
+  connect to a MAC through a standard MII, RMII, or RGMII interface
+
+  Specifications about the Ethernet PHY can be found at:
+    http://www.ti.com/lit/ds/symlink/dp83822i.pdf
+
+allOf:
+  - $ref: "ethernet-phy.yaml#"
+
+properties:
+  reg:
+    maxItems: 1
+
+  ti,link-loss-low:
+    type: boolean
+    description: |
+       DP83822 PHY in Fiber mode only.
+       Sets the DP83822 to detect a link drop condition when the signal goes
+       high.  If not set then link drop will occur when the signal goes low.
+       This property is only applicable if the fiber mode support is strapped
+       to on.
+
+  ti,fiber-mode:
+    type: boolean
+    description: |
+       DP83822 PHY only.
+       If present the DP83822 PHY is configured to operate in fiber mode
+       Fiber mode support can also be strapped. If the strap pin is not set
+       correctly or not set at all then this boolean can be used to enable it.
+       If the fiber mode is not strapped then signal detection for the PHY
+       is disabled.
+       In fiber mode, auto-negotiation is disabled and the PHY can only work in
+       100base-fx (full and half duplex) modes.
+
+  rx-internal-delay-ps:
+    description: |
+       DP83822 PHY only.
+       Setting this property to a non-zero number sets the RX internal delay
+       for the PHY.  The internal delay for the PHY is fixed to 3.5ns relative
+       to receive data.
+
+  tx-internal-delay-ps:
+    description: |
+       DP83822 PHY only.
+       Setting this property to a non-zero number sets the TX internal delay
+       for the PHY.  The internal delay for the PHY is fixed to 3.5ns relative
+       to transmit data.
+
+required:
+  - reg
+
+examples:
+  - |
+    mdio0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      ethphy0: ethernet-phy@0 {
+        reg = <0>;
+        rx-internal-delay-ps = <1>;
+        tx-internal-delay-ps = <1>;
+      };
+    };
+
+...