clk: Add fixed-factor clock driver

This patch adds fixed-factor clock driver which derives clock
rate by dividing (div) and multiplying (mult) fixed factors
to a parent clock.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/device-tree-bindings/clock/fixed-factor-clock.txt b/doc/device-tree-bindings/clock/fixed-factor-clock.txt
new file mode 100644
index 0000000..1bae852
--- /dev/null
+++ b/doc/device-tree-bindings/clock/fixed-factor-clock.txt
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+Binding for simple fixed factor rate clock sources.
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be "fixed-factor-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- clock-div: fixed divider.
+- clock-mult: fixed multiplier.
+- clocks: parent clock.
+
+Optional properties:
+- clock-output-names : From common clock binding.
+
+Example:
+	clock {
+		compatible = "fixed-factor-clock";
+		clocks = <&parentclk>;
+		#clock-cells = <0>;
+		clock-div = <2>;
+		clock-mult = <1>;
+	};