iMX6ULL cpu frequency

[aermakov]

I am using cpu iMX6ULL, and I need to set CPU and system bus frequency manually.

Linux devicetree have several presets for CPU and soc frequency. Can I add there my custom value (It will be multiply 24)?

And how do I know the voltage for this frequency?

[Yuri]

Hello,

Theoretically it is possible to add new custom working setpoints, but hardly it may

be recommended, since - because of system complexity - it will require much efforts

to debug and test new setpoints for all conditions.

Regards,

Yuri.

[aermakov]

What are the setpoints? Is it CPU frequency and voltage, and SOC frequency and voltage? Are the SOC and CPU frequencies related, or are they set separately from each other?

We have the ability to test setpoints in different conditions.

[Yuri]

Hello,

  Use sections  2.5.3 [CPU Frequency Scaling (CPUFREQ)] and  2.5.4 (Dynamic Bus

Frequency) of the i.MX Linux Reference Manual for more details.

https://www.nxp.com/webapp/Download?colCode=imx-yocto-L4.14.98_2.0.0_ga

imx6ul.dtsi\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

Regards,

Yuri.

[aermakov]

Latest linux kernel version with busfreq driver I found is 4.9 at the git://git.freescale.com/imx/linux-imx.git repository. Is there newer kernel version with busfreq driver?

[Yuri]

Hello,

   Look at Table 2-15 (BusFrequency Driver Files) in "i.MX_Reference_Manual.pdf".

https://www.nxp.com/webapp/Download?colCode=imx-yocto-L4.14.98_2.0.0_ga

Regards,

Yuri.