dt-bindings: phy: add binding for the Lantiq VRX200 and ARX300 PCIe PHYs

Add the bindings for the PCIe PHY on Lantiq VRX200 and ARX300 SoCs.
The IP block contains settings for the PHY and a PLL.
The PLL mode is configurable through a dedicated #phy-cell in .dts.

Signed-off-by: Martin Blumenstingl <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

Documentation/devicetree/bindings/phy/lantiq,vrx200-pcie-phy.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/lantiq,vrx200-pcie-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Lantiq VRX200 and ARX300 PCIe PHY Device Tree Bindings
+
+maintainers:
+  - Martin Blumenstingl <[e-mail]>
+
+properties:
+  "#phy-cells":
+    const: 1
+    description: selects the PHY mode as defined in <dt-bindings/phy/phy-lantiq-vrx200-pcie.h>
+
+  compatible:
+    enum:
+      - lantiq,vrx200-pcie-phy
+      - lantiq,arx300-pcie-phy
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: PHY module clock
+      - description: PDI register clock
+
+  clock-names:
+    items:
+      - const: phy
+      - const: pdi
+
+  resets:
+    items:
+      - description: exclusive PHY reset line
+      - description: shared reset line between the PCIe PHY and PCIe controller
+
+  resets-names:
+    items:
+      - const: phy
+      - const: pcie
+
+  lantiq,rcu:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: phandle to the RCU syscon
+
+  lantiq,rcu-endian-offset:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: the offset of the endian registers for this PHY instance in the RCU syscon
+
+  lantiq,rcu-big-endian-mask:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: the mask to set the PDI (PHY) registers for this PHY instance to big endian
+
+  big-endian:
+    description: Configures the PDI (PHY) registers in big-endian mode
+    type: boolean
+
+  little-endian:
+    description: Configures the PDI (PHY) registers in big-endian mode
+    type: boolean
+
+required:
+  - "#phy-cells"
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+  - lantiq,rcu
+  - lantiq,rcu-endian-offset
+  - lantiq,rcu-big-endian-mask
+
+additionalProperties: false
+
+examples:
+  - |
+    pcie0_phy: phy@106800 {
+        compatible = "lantiq,vrx200-pcie-phy";
+        reg = <0x106800 0x100>;
+        lantiq,rcu = <&rcu0>;
+        lantiq,rcu-endian-offset = <0x4c>;
+        lantiq,rcu-big-endian-mask = <0x80>; /* bit 7 */
+        big-endian;
+        clocks = <&pmu 32>, <&pmu 36>;
+        clock-names = "phy", "pdi";
+        resets = <&reset0 12 24>, <&reset0 22 22>;
+        reset-names = "phy", "pcie";
+        #phy-cells = <1>;
+    };
+
+...

include/dt-bindings/phy/phy-lantiq-vrx200-pcie.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 Martin Blumenstingl <[e-mail]>
+ */
+
+#define LANTIQ_PCIE_PHY_MODE_25MHZ		0
+#define LANTIQ_PCIE_PHY_MODE_25MHZ_SSC		1
+#define LANTIQ_PCIE_PHY_MODE_36MHZ		2
+#define LANTIQ_PCIE_PHY_MODE_36MHZ_SSC		3
+#define LANTIQ_PCIE_PHY_MODE_100MHZ		4
+#define LANTIQ_PCIE_PHY_MODE_100MHZ_SSC		5