Virtual devices (cpufreq etc) and DT

I'm trying to work out how our cpufreq driver fits in with device tree 
bindings.  We have a simple driver that just takes a struct clk and 
calls clk_set_rate() on it.  Is a node in the device tree the right way 
to do this as it isn't really a physical device?  I have the PLL in the 
clocks group of the DT:

	clocks {
		...

		arm_clk: clock@11 {
			compatible = "picochip,pc3x3-pll";
			reg = <0x800a0050 0x8>;
			picoxcell,min-freq = <140000000>;
			picoxcell,max-freq = <700000000>;
			ref-clock = <&ref_clk>, "ref";
			clock-outputs = "cpu";
		};
	};

so I could reference that.  The of clk interface also requires a struct 
device for getting the clk so I guess this is needed...

Jamie