CPU scaling operating-points for iMX6Q Sabre Lite board

[blevefrancesco]

I'm running on a iMX6Q Sabre Lite board.

For Building the imx6q-sabrelite.dtb file should be used the following files (imx6q-sabrelite.dts, imx6q.dtsi, imx6qdl.dtsi, imx6ql-sabrelite.dtsi and so on)

In the file arch/arm/boot/dts/imx6q.dtsi, particularly, are listed the CPU scaling operating points:

     cpu0: cpu@0 {

          compatible = "arm,cortex-a9";

     device_type = "cpu";

     reg = <0>;

     next-level-cache = <&L2>;

     operating-points = <

          /* kHz    uV */

          1200000 1275000

          996000  1250000

          852000  1250000

          792000  1175000

          396000  975000

So these should be as far as I understood the scaling operating points passed from the bootloader to the kernel.

Am I right?

However, when I run the following command on both Yocto Linux and Android 5.1.1:

     cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

I get only these available scaling operating points:

     396000 792000 996000

why are the 852000  and 1200000 frequencies not included in the CPU scaling policy?

Thank you in advance!

[igorpadykov · Accepted solution]

Hi Francesco

this depends on frequency grade (can be read from fuse SPEED_GRADING[5:4]):

for example 1.2GHz part: MCIMX6Q5EYM12AC, MCIMX6Q6AVT08AC - 852MHz

Best regards

igor

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