Binding for Silicon Labs 570, 571, 598 and 599 programmable
I2C clock generators.

Reference
This binding uses the common clock binding[1]. Details about the devices can be
found in the data sheets[2][3].

[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
[2] Si570/571 Data Sheet
    https://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf
[3] Si598/599 Data Sheet
    https://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf

Required properties:
 - compatible: Shall be one of "silabs,si570", "silabs,si571",
			       "silabs,si598", "silabs,si599"
 - reg: I2C device address.
 - #clock-cells: From common clock bindings: Shall be 0.
 - factory-fout: Factory set default frequency. This frequency is part specific.
		 The correct frequency for the part used has to be provided in
		 order to generate the correct output frequencies. For more
		 details, please refer to the data sheet.
 - temperature-stability: Temperature stability of the device in PPM. Should be
			  one of: 7, 20, 50 or 100.

Optional properties:
 - clock-output-names: From common clock bindings. Recommended to be "si570".
 - clock-frequency: Output frequency to generate. This defines the output
		    frequency set during boot. It can be reprogrammed during
		    runtime through the common clock framework.

Example:
	si570: clock-generator@5d {
		#clock-cells = <0>;
		compatible = "silabs,si570";
		temperature-stability = <50>;
		reg = <0x5d>;
		factory-fout = <156250000>;
	};