I2C iMX6Q PMIC issue (failed to scale vddsoc up)

[matteogeromin]

Hi all,

I'm having some issue with imx6Q and Android L5 (kernel 3.10.53) on a custom SOM board.

After a long use some times cpufreq driver cannot scale vddsoc up and the CPU frequency remains at minimum of 396MHz. Here is the output of the error:

[103186.023910] imx6-cpufreq imx6-cpufreq.0: failed to scale vddsoc up: -5

It seems that processor cannot communicate with the PMIC (MMPF0100F0EP) to scale up the VDDSOC.

Some times it appens on VDDARM, and some times on scale up or on scale down.

When this error occurs we can only reboot the board to fix the problem.

The same OS on our imx6DL som board does not show this issue.

Could it be an I2C bus stuck problem, or could it be a SW problem?

Thanks in advance

Best Regards,

Matteo Geromin

#imx6q pmic

[igorpadykov]

Hi Matteo

one can check hardware using i.MX6 System Development User’s Guide,

check i2c signals with oscilloscope.

https://www.nxp.com/docs/en/user-guide/IMX6DQ6SDLHDG.pdf

Also one can check processor temperature as linux slows down operating

frequency (and decreases VDDARM voltage) when chip is heated.

May be useful AN4579  i.MX6 Series Thermal Management Guidelines
http://www.nxp.com/docs/en/application-note/AN4579.pdf

Best regards
igor
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[tommyduan]

How is this problem finally solved?