topic Re: iMX6ULL cpu frequency in i.MX Processors

iMX6ULL cpu frequency

aermakov — Tue, 01 Oct 2019 11:47:11 GMT

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?

Re: iMX6ULL cpu frequency

Yuri — Tue, 01 Oct 2019 16:51:28 GMT

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.

Re: iMX6ULL cpu frequency

aermakov — Wed, 02 Oct 2019 05:00:57 GMT

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.

Re: iMX6ULL cpu frequency

Yuri — Wed, 02 Oct 2019 05:48:45 GMT

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.

Re: iMX6ULL cpu frequency

aermakov — Wed, 02 Oct 2019 10:49:14 GMT

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?

Re: iMX6ULL cpu frequency

Yuri — Thu, 03 Oct 2019 04:51:03 GMT

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.