topic cpufreq won't show up in i.MX Processors

cpufreq won't show up

niklasmolin — Thu, 21 Dec 2017 03:41:33 GMT

I'm compiling linux image (4.14) for an i.mx6QP and noticed that cpufreq doesn't show up under /sys/devices/systems/cpu/cpu0

What could the be reason why it doesn't show up?

Re: cpufreq won't show up

igorpadykov — Thu, 21 Dec 2017 05:18:47 GMT

Hi Niklas

please try L4.1.15 offical nxp bsps (there is no 4.14) described on

i.MX 6 / i.MX 7 Series Software and Development Tool|NXP

cpufreq driver is described in Chapter 23 CPU Frequency Scaling (CPUFREQ) Driver

attached Linux Manual.

Best regards
igor
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Re: cpufreq won't show up

niklasmolin — Thu, 21 Dec 2017 05:39:05 GMT

Hi Igor.

Thanks for your response.

The reason we we decided to go for the latest Linux version because we could not get the PCI to work in our design when using 4.1.x version.

I know the CPU frequency driver worked when we were running the image on an i.mx6D, but when I ran on the i.mxQP it didn't show up.

The only difference is that I had to change u-boot when running on the QP version.

Regards,

Niklas

Re: cpufreq won't show up

igorpadykov — Thu, 21 Dec 2017 07:34:46 GMT

Hi Niklas

there are several kernels and versions but not all of them have comprehensive

i.MX6QP support

[meta-freescale] Issue with freescale git server at git.freescale.com

suggest to test with nxp official bsps described on

i.MX 6 / i.MX 7 Series Software and Development Tool|NXP

Best regards
igor

Re: cpufreq won't show up

niklasmolin — Thu, 21 Dec 2017 16:57:51 GMT

Hi Igor.

For the moment I'm just interested to see that it's running with full speed.

Is there an easy way to verify that it's running with the highest frequency (since I don't have access the frequency info kernel). Or is it to just read some of the registers to see what the clock is set to?

Regards,

Niklas

Re: cpufreq won't show up

igorpadykov — Thu, 21 Dec 2017 23:37:11 GMT

Hi Niklas

one can output arm_clk_root on CLKO pin using CCM_CCOSR register

and test it with oscilloscope.

Best regards
igor

Re: cpufreq won't show up

niklasmolin — Tue, 16 Jan 2018 13:26:24 GMT

Found the issue.

There was mistake in my .dts file.