dt-bindings: clk: sprd: add bindings for sc9863a clock controller

add a new bindings to describe sc9863a clock compatible string.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lkml.kernel.org/r/20200304072730.9193-4-zhang.lyra@gmail.comReviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/sprd,sc9863a-clk.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2019 Unisoc Inc.
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/clock/sprd,sc9863a-clk.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: SC9863A Clock Control Unit Device Tree Bindings
+
+maintainers:
+  - Orson Zhai <orsonzhai@gmail.com>
+  - Baolin Wang <baolin.wang7@gmail.com>
+  - Chunyan Zhang <zhang.lyra@gmail.com>
+
+properties:
+  "#clock-cells":
+    const: 1
+
+  compatible :
+    enum:
+      - sprd,sc9863a-ap-clk
+      - sprd,sc9863a-aon-clk
+      - sprd,sc9863a-apahb-gate
+      - sprd,sc9863a-pmu-gate
+      - sprd,sc9863a-aonapb-gate
+      - sprd,sc9863a-pll
+      - sprd,sc9863a-mpll
+      - sprd,sc9863a-rpll
+      - sprd,sc9863a-dpll
+      - sprd,sc9863a-mm-gate
+      - sprd,sc9863a-apapb-gate
+
+  clocks:
+    minItems: 1
+    maxItems: 4
+    description: |
+      The input parent clock(s) phandle for this clock, only list fixed
+      clocks which are declared in devicetree.
+
+  clock-names:
+    minItems: 1
+    maxItems: 4
+    items:
+      - const: ext-26m
+      - const: ext-32k
+      - const: ext-4m
+      - const: rco-100m
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - '#clock-cells'
+
+if:
+  properties:
+    compatible:
+      enum:
+        - sprd,sc9863a-ap-clk
+        - sprd,sc9863a-aon-clk
+then:
+  required:
+    - reg
+
+else:
+  description: |
+    Other SC9863a clock nodes should be the child of a syscon node in
+    which compatible string shoule be:
+            "sprd,sc9863a-glbregs", "syscon", "simple-mfd"
+
+    The 'reg' property for the clock node is also required if there is a sub
+    range of registers for the clocks.
+
+examples:
+  - |
+    ap_clk: clock-controller@21500000 {
+      compatible = "sprd,sc9863a-ap-clk";
+      reg = <0 0x21500000 0 0x1000>;
+      clocks = <&ext_26m>, <&ext_32k>;
+      clock-names = "ext-26m", "ext-32k";
+      #clock-cells = <1>;
+    };
+
+  - |
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      ap_ahb_regs: syscon@20e00000 {
+        compatible = "sprd,sc9863a-glbregs", "syscon", "simple-mfd";
+        reg = <0 0x20e00000 0 0x4000>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0 0x20e00000 0x4000>;
+
+        apahb_gate: apahb-gate@0 {
+          compatible = "sprd,sc9863a-apahb-gate";
+          reg = <0x0 0x1020>;
+          #clock-cells = <1>;
+        };
+      };
+    };
+
+...