Linux/OMAP-L138: How to set ARM CPU Frequency for Linux

Thank you for your response Yordan.

I have added the following to da850-lcdk.dts, trying to follow the recommendations in Documentation/devicetree/bindings/opp/opp.txt and bindings/arm/cpus.txt as best as I can:

	cpus {
		#address-cells = <1>;
		#size-cells = <0>;
		cpu@0 {
			compatible = "arm,arm,arm926ej-s";
			enable-method = "ti,da850";
			device_type = "cpu";
			reg = <0>;

			operating-points-v2 = <&cpu0_opp_table>;
		};
	};
	cpu0_opp_table: opp_table0 {
		compatible = "operating-points-v2-ti-cpu";



		opp50@300000000 {
			opp-hz = /bits/ 64 <300000000>;
			opp-microvolt = <1200000>;
		};
		opp100@456000000 {
			opp-hz = /bits/ 64 <456000000>;
			opp-microvolt = <1300000>;
		};
	};

And the following have been set in .config:

CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_STAT=y
CONFIG_CPU_FREQ_STAT_DETAILS=y
CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPUFREQ_DT=y
CONFIG_CPUFREQ_DT_PLATDEV=y

The directory /sys/devices/system/cpu/cpu0/cpufreq does not exist.

ls /sys/devices/system/cpu/cpu0 shows the following:
crash_notes of_node subsystem uevent crash_notes_size power topology

And /sys/devices/system/cpu/cpufreq is empty.  I can verify the correct device tree has been loaded by examining /sys/devices/system/cpu/cpu0/of_node.

There seems to be a number of discrepancies between the am33xx and the davinci system.  That would make sense, since they're different platforms.  The omapl138 documentation makes no mention of the operating points like the AM335x documents do.  There is also no mention of efuses or the syscon module referenced in the am33xx.dtsi in the omapl138 documentation.

Digging a little deeper, it seems that the davinci-cpufreq driver may not support the device tree.  The copyright in the file predates the use of the device tree in Linux, and seems to only use platform devices.  It doesn't appear to make any attempts to use the "of_" functions mentioned in this article (lwn.net/Articles/448502/).  It seems to me that the Linux cpufreq driver may be loading, but is not successfully probing the davinci driver (or the davinci-cpufreq driver is not loading).  The omap-cpufreq and ti-cpufreq drivers do not seem to support the da8xx family.  All of that said, I find it unlikely that I am the first to try to set the Linux CPU speed in Processor SDK 4.0 on the OMAP-L138, so it has to have worked, right?  I suspect I've missed something/do not completely understand how everything comes together.

Is there a way to simply force the board to boot at 456MHz, without any of the CPUFreq drivers?

Jeff