dt-bindings: clock: Document qcom,hfpll

Adds bindings document for qcom,hfpll instantiated within
the Krait processor subsystem as separate register region.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Craig Tatlor <ctatlor97@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/qcom,hfpll.txt

@@ -0,0 +1,60 @@
+High-Frequency PLL (HFPLL)
+
+PROPERTIES
+
+- compatible:
+	Usage: required
+	Value type: <string>:
+		shall contain only one of the following. The generic
+		compatible "qcom,hfpll" should be also included.
+
+                        "qcom,hfpll-ipq8064", "qcom,hfpll"
+                        "qcom,hfpll-apq8064", "qcom,hfpll"
+                        "qcom,hfpll-msm8974", "qcom,hfpll"
+                        "qcom,hfpll-msm8960", "qcom,hfpll"
+
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: address and size of HPLL registers. An optional second
+		    element specifies the address and size of the alias
+		    register region.
+
+- clocks:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: reference to the xo clock.
+
+- clock-names:
+	Usage: required
+	Value type: <stringlist>
+	Definition: must be "xo".
+
+- clock-output-names:
+	Usage: required
+	Value type: <string>
+	Definition: Name of the PLL. Typically hfpllX where X is a CPU number
+		    starting at 0. Otherwise hfpll_Y where Y is more specific
+		    such as "l2".
+
+Example:
+
+1) An HFPLL for the L2 cache.
+
+	clock-controller@f9016000 {
+		compatible = "qcom,hfpll-ipq8064", "qcom,hfpll";
+		reg = <0xf9016000 0x30>;
+		clocks = <&xo_board>;
+		clock-names = "xo";
+		clock-output-names = "hfpll_l2";
+	};
+
+2) An HFPLL for CPU0. This HFPLL has the alias register region.
+
+	clock-controller@f908a000 {
+		compatible = "qcom,hfpll-ipq8064", "qcom,hfpll";
+		reg = <0xf908a000 0x30>, <0xf900a000 0x30>;
+		clocks = <&xo_board>;
+		clock-names = "xo";
+		clock-output-names = "hfpll0";
+	};