How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

[michael_lee]

Dear NXP and All,

I am debugging the i.mx6q chip on the Linux 3.14.28, sabresd demo board, I use the default software, Its freq is 792MHz, my chip support 1GHz, so I want to run the 996MHz, Can anyone give me the steps about the freq change?  Thanks.

I have read the "i.MX_6_Linux_Reference_Manual.pdf", Chapter 24 CPU Frequency Scaling (CPUFREQ) Driver,

but It doesn't say how to change freq?

Best Regards,

[igorpadykov]

Hi Michael

what image is used in the case, could you try Demo image on

L3.14.28_1.0.0_iMX6QDLS_BUNDLE

http://www.nxp.com/webapp/Download?colCode=L3.14.28_1.0.0_iMX6QDLS_BUNDLE&Parent_nodeId=133769948107...

also please check (with jtag or in uboot ) fuse SPEED_GRADING[5:4] address 0x440[17:16]

Table 5-10. Fusemap Descriptions  i.MX6DQ Reference Manual (rev.0  2/2016)

http://cache.nxp.com/files/soft_dev_tools/doc/support_info/iMX6DQPRM.pdf

Best regards

igor

[michael_lee]

Dear igor,

I use the mfgtools which support the L3.14.28 version, and use the default image;

do you know the command like this "echo 792000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed" can be used for the L3.0.35 version,

Best regards,

[BiyongSUN]

Michael,

It is a Linux topic, please read the Linux documents

Documentation/cpu-freq/user-guide.txt

Documentation/cpu-freq/governors.txt

This is in governors.txt

scaling_available_governors : this file shows the CPUfreq governors available in this kernel. You can see the

    currently activated governor in

scaling_governor,  and by "echoing" the name of another governor you can change it. Please note

    that some governors won't load - they only

    work on some specific architectures or

    processor

Please check if the current governor is "userspace". Normally the gavernors could be "userspace performance interactive ondemand conservative powersave".

If not, please change it to  "userspace".

[igorpadykov]

Hi Michael

default bsp supports it, pelase refer to operating-points in imx6q.dtsi

linux-2.6-imx.git - Freescale i.MX Linux Tree

for procedure of changing frequency refer to Chapter 24

CPU Frequency Scaling (CPUFREQ) Driver attached Linux Manual.

Best regards

igor

-----------------------------------------------------------------------------------------------------------------------

Note: If this post answers your question, please click the Correct Answer button. Thank you!

-----------------------------------------------------------------------------------------------------------------------

[michael_lee]

Dear igor,

default BSP suport DVFS, but usually it works on 792MHz, so I want to work on 996MHz,

and which doc you suggested that it doesn't show how to change the freq?

do you have the doc about this issue step by step to guide us to configure it ?

or can you show me an example, we can download it to verify, thanks.

Best Regards,

[igorpadykov]

Hi Michael

it does show how to change the freq, for example:

echo 792000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

To view what values the CPU frequency can be changed to in KHz (The values in the

first column are the frequency values) use this command:

cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

what is full processor part number in the case ?

Best regards

igor

[michael_lee]

Dear igor,

Do you check the command which you suggest?

On the Linux 3.14.28, it can't run!

root@imx6qsabresd:/sys/devices/system/cpu/cpu0# ls -l

drwxr-xr-x    4 root     root             0 Jun  3 00:29 cpuidle

-rw-r--r--    1 root     root          4096 Jun  3 00:29 online

drwxr-xr-x    2 root     root             0 Jun  3 00:29 power

lrwxrwxrwx    1 root     root             0 Jan  1  1970 subsystem -> ../../../../bus/cpu

drwxr-xr-x    2 root     root             0 Jun  3 00:29 topology

-rw-r--r--    1 root     root          4096 Jan  1  1970 uevent

there is not the file "cpufreq/stats/time_in_state“

Have you check that?

which part number I use is MCIMX6Q5EYM10AD.

Best Regards,