clk: cdce9xx: add support for cdce9xx clock synthesizer

Add support for CDCE913/925/937/949 family of devices. These are modular
PLL-based low cost, high performance, programmable clock synthesizers,
multipliers and dividers. They generate up to 9 output clocks from a
single input frequency. The initial version of the driver does not
support programming of the PLLs, and thus they run in the bypass mode
only. The code is loosely based on the linux kernel cdce9xx driver.

Signed-off-by: Tero Kristo <t-kristo@ti.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/clock/ti,cdce9xx.txt b/doc/device-tree-bindings/clock/ti,cdce9xx.txt
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+Binding for TI CDCE913/925/937/949 programmable I2C clock synthesizers.
+
+Reference
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] http://www.ti.com/product/cdce913
+[3] http://www.ti.com/product/cdce925
+[4] http://www.ti.com/product/cdce937
+[5] http://www.ti.com/product/cdce949
+
+The driver provides clock sources for each output Y1 through Y5.
+
+Required properties:
+ - compatible: Shall be one of the following:
+	- "ti,cdce913": 1-PLL, 3 Outputs
+	- "ti,cdce925": 2-PLL, 5 Outputs
+	- "ti,cdce937": 3-PLL, 7 Outputs
+	- "ti,cdce949": 4-PLL, 9 Outputs
+ - reg: I2C device address.
+ - clocks: Points to a fixed parent clock that provides the input frequency.
+ - #clock-cells: From common clock bindings: Shall be 1.
+
+Optional properties:
+ - xtal-load-pf: Crystal load-capacitor value to fine-tune performance on a
+                 board, or to compensate for external influences.
+
+For all PLL1, PLL2, ... an optional child node can be used to specify spread
+spectrum clocking parameters for a board.
+  - spread-spectrum: SSC mode as defined in the data sheet.
+  - spread-spectrum-center: Use "centered" mode instead of "max" mode. When
+    present, the clock runs at the requested frequency on average. Otherwise
+    the requested frequency is the maximum value of the SCC range.
+
+
+Example:
+
+	clockgen: cdce925pw@64 {
+		compatible = "cdce925";
+		reg = <0x64>;
+		clocks = <&xtal_27Mhz>;
+		#clock-cells = <1>;
+		xtal-load-pf = <5>;
+		/* PLL options to get SSC 1% centered */
+		PLL2 {
+			spread-spectrum = <4>;
+			spread-spectrum-center;
+		};
+	};