dt-bindings: clock: Add Qualcomm A7 PLL binding

Add devicetree YAML binding for Cortex A7 PLL clock in Qualcomm
platforms like SDX55.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210118041156.50016-4-manivannan.sadhasivam@linaro.orgReviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/qcom,a7pll.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/qcom,a7pll.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm A7 PLL Binding
+
+maintainers:
+  - Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+description:
+  The A7 PLL on the Qualcomm platforms like SDX55 is used to provide high
+  frequency clock to the CPU.
+
+properties:
+  compatible:
+    enum:
+      - qcom,sdx55-a7pll
+
+  reg:
+    maxItems: 1
+
+  '#clock-cells':
+    const: 0
+
+  clocks:
+    items:
+      - description: board XO clock
+
+  clock-names:
+    items:
+      - const: bi_tcxo
+
+required:
+  - compatible
+  - reg
+  - '#clock-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/qcom,rpmh.h>
+    a7pll: clock@17808000 {
+        compatible = "qcom,sdx55-a7pll";
+        reg = <0x17808000 0x1000>;
+        clocks = <&rpmhcc RPMH_CXO_CLK>;
+        clock-names = "bi_tcxo";
+        #clock-cells = <0>;
+    };