How can I set and check AM335x frequency without PMIC

AFu Lai

Hi,

My platform uses a fixed core voltage source and no PMIC is used.

So I tried to set a fixed cpu frequency in u-boot function am33xx_spl_board_init with parameter MPUPLL_M_300 and MPUPLL_M_600.

But I found the the dhrystone scores of these two PLL settings are the same .

Since SDK doesn't well support system w/o PMIC, the cpufreq can't be initialized correctly.

Therefore, I can't get frequency information from /sys/devices/system/cpu/cpu0/cpufreq.

How can I set and check it correctly?

0 Wolfgang Muees1 over 10 years ago

Genius 3685 points

IMHO, the linux kernel is setting the MPU PLL at startup. So your settings in u-boot are invalidated.

0 AFu Lai over 10 years ago in reply to Wolfgang Muees1

I'm not sure for this since the system has no PMIC and frequency control functions are all disabled.

I'll check the source to see if I can set a fixed value.

Any keyword for searching this PLL setting?

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