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CPU frequency issue of STM32MP157D

zengyixiang
Associate III

The Linux version I am using is 6.1.28, and my power management is a discrete component. "VDD_CORE" is actually 1.212V, and in the device tree it looks like this:

	vddcore: regulator-vddcore {
        compatible = "regulator-fixed";
		regulator-name = "vddcore";
		regulator-min-microvolt = <1200000>;
		regulator-max-microvolt = <1350000>;
		regulator-always-on;
        regulator-boot-on;
	};

If I follow the above settings, my "/sys/devices/system/cpu/cpufreq/" will be empty, but if I change the 1200000 in "regulator min microvolt=<1200000>;" to 1350000, it will be normal. Why is this? 

1 ACCEPTED SOLUTION

Accepted Solutions
Olivier GALLIEN
ST Employee

Hi @zengyixiang 

 

Sorry this is not clear , if you have a static discrete VDD_CORE to  1.2V you can't support the 1.35 / 800Mhz  opp mode. 

You might put 1200000 in both min / max and check opp_table to let only a single conf. 

 

How to change the CPU frequency - stm32mpu

 

Olivier 

Olivier GALLIEN
In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

View solution in original post

1 REPLY 1
Olivier GALLIEN
ST Employee

Hi @zengyixiang 

 

Sorry this is not clear , if you have a static discrete VDD_CORE to  1.2V you can't support the 1.35 / 800Mhz  opp mode. 

You might put 1200000 in both min / max and check opp_table to let only a single conf. 

 

How to change the CPU frequency - stm32mpu

 

Olivier 

Olivier GALLIEN
In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.