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Ara.1
Ara.1
Associate III
October 21, 2021
Solved

STM32MP1 DIE TEMP- FREQ-VBAT

is there any way find dts config /sys/ file to check stm32mp1  in linux sdk ?

cpu temp 

freq

battery voltage vbat measurement.

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Kevin HUBER
Kevin HUBERBest answer
ST Employee
October 28, 2021

Hi @Ara.1​ ,

I don't know why, but it seems that these kernel configs are missing in your configuration.

CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_STAT=y
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=m
CONFIG_CPU_FREQ_GOV_USERSPACE=m
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m
CONFIG_CPU_FREQ_GOV_SCHEDUTIL=y
CONFIG_CPUFREQ_DT=y

Please add them by enabling:

0693W00000GVoWSQA1.png0693W00000GVoVyQAL.png 

If you are using the starter package, they are already enabled, but for testing purpose, I removed these configurations from my linux on my MP157f-dk2 with the starter package and I get the same issue than you.

root@stm32mp1:~# cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq
cat: /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq: No such file or directory

Please have a look at this page if you don't know how to modify your linux configuration: https://wiki.st.com/stm32mpu/wiki/Menuconfig_or_how_to_configure_kernel

PS: If you built your kernel in a different build directory (different of kernel source code directory), remember to specify it when using the make command of the wiki page.

Hope it helps,

Regards,

Kevin

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7 replies

Ara.1
Ara.1Author
Associate III
October 22, 2021

is there any way find dts config /sys/ file to check stm32mp1 

cpu temp  ?

freq ?

battery volatge vbat measurement. ?

PatrickF
PatrickF
ST Employee
October 22, 2021

Hello @Ara.1​ 

To know the current CPU frequency (in Hz), you could use this standard Linux command:

  • cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

To know the die temperature using DTS IP, you could use this standard Linux command:

  • cat cat /sys/class/thermal/thermal_zone0/temp

Result to be divided by 1000 for a temperature value in °C

Note that on 800MHz devices with starter package, DFVS is implemented, which automatically reduce cpu frequency to 400MHz and VDDCORE in case of low activity (or if too hot die temperature).

Please have a look to https://wiki.st.com/stm32mpu/wiki/How_to_change_the_CPU_frequency

To measure the VBAT value, you should use the internal ADC2 channel 15, but currently, this is not available on Linux.

Development team are working on it and should be available in next ecosystem revision (expected in few weeks from now), and I understand at that time it could be accessed using IIO framework.

VBAT on ADC2 Channel 15 is already available on Cortex-M4 using HAL SW.

Regards.

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Ara.1
Ara.1Author
Associate III
October 22, 2021

Hi Patric,

Temperature info got it

but CPU cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq is not there

for cpu freq any dts change required?

PatrickF
PatrickF
ST Employee
October 22, 2021

Hi,

Tested ok on my side with both Ecosystem V3 (kernel 5.10) and Ecosystem V2 (kernel 5.4) using Starter Package on both STM32MP157F-DK2 and STM32MP157C-DK2 boards.

Maybe missing the &cpu0_opp_table, even if fixed frequency on your board (although obviously useless to check the frequency if it is fixed).

see https://wiki.st.com/stm32mpu/wiki/How_to_change_the_CPU_frequency#OPP_table

Regards.

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Ara.1
Ara.1Author
Associate III
October 25, 2021

https://wiki.st.com/stm32mpu/wiki/How_to_change_the_CPU_frequency#OPP_table

is this link to be handled in kernel dts ? if not, let us know how to do it ?

yes if its cpu freq fixed its no use for us, but i need to see the adoption of frequency based on load at cpu side ? do we have any window on dts file configfor gettting the cur freq ?

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