[IMX93] It have no cpufreq directory under sys_fs.

[takayuki_ishii]

Hello community.

I just try to control CPU frequency or governor for i.MX93-EVK.

But it have no cpufreq directory under /sys/devices/system/cpu/cpu0 and cpu1.

I check it both Linux BSP L6.1.1_1.0.0 and L6.1.22_2.0.0.

In Application note AN13917 i.MX 93 Power Consumption Measurement rev0.

It have result both 1.7GHz and 1.4GHz CPU frequency.

So I think it have some method to control cpu frequency.

Other board (i.MX7D-SABRE) with Linux BSP L6.1.22_2.0.0, it can see cpufreq directory.

Does IMX93-EVK not support CPU frequency scaling?

Best regards,

Ishii.

[Zhiming_Liu · Accepted solution]

Hi @takayuki_ishii 

i.MX93 doesn't support DVFS, you can switch to nominal mode with below command:

root@imx93evk:~# echo 1 > /sys/devices/platform/imx93-lpm/mode
root@imx93evk:~# mhz
1398 MHz, 0.7153 nanosec clock
root@imx93evk:~#

Best Regards

Zhiming 

[takayuki_ishii]

Hello @Zhiming_Liu 

thank you for your quick response.

I can change it on my board.

root@imx93-11x11-lpddr4x-evk:~# echo 1 > /sys/devices/platform/imx93-lpm//mode
[13414.223659] System switching to ND mode...
root@imx93-11x11-lpddr4x-evk:~# mhz
1398 MHz, 0.7153 nanosec clock
root@imx93-11x11-lpddr4x-evk:~# cat /sys/devices/platform/imx93-lpm/mode
System is in ND mode with DDR 1866 MTS!

Best regards,

Ishii.

[Vladeta_ljubisavljevic]

Where one can find this mhz tool?

[takayuki_ishii]

Hello @Vladeta_ljubisavljevic ,

I think that it seems part of lmbench.

~/imx-bsp-6.12.20/build-imx93-14x14-lpddr4x-evk-xwayland/tmp/work/armv8a-poky-linux/lmbench/3.0-a9/lmbench-3.0-a9/src/mhz.c

Best regards,

Ishii.

[Vladeta_ljubisavljevic]

Yes it is in that recipe. Thanks a lot!