About imx7d chip CPU frequency is not normal

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About imx7d chip CPU frequency is not normal

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864535720
Contributor II

Hello everyone,
my development board is IMX7DSABRE. Linux kernel version is 4.9.88
During use, we found that the CPU model is MCIMX7D7DVM10SD. The CPU frequency corresponding to this model in the manual should be 1.0GHz, but we can view it through cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq. It is found that the printed CPU frequency is 1.2GHz, and our CPU mode is performance.
Later we use the MCIMX7D5EVM10SD chip. In the performance mode of the CPU, its frequency is still 1.2GHz. This data is inconsistent with the data in the manual. Why is this?

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igorpadykov
NXP Employee
NXP Employee

Hi 其东 刘

one can adjust dts cpu operating point according to its datasheet:

cpus {cpu0: cpu@0 {
    operating-points = ..

imx7d.dtsi\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

Best regards
igor
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890 Views
864535720
Contributor II

Hi,igorpadykov

The model of our chip, the frequency of the CPU described in the manual is 1GHz, then should I modify the device tree to the following information:
cpu0: cpu@0 {
operating-points = <
/* KHz uV */
996000 1075000
792000 975000
>;
clock-frequency = <996000000>;
};

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igorpadykov
NXP Employee
NXP Employee

yes, correct.

Best regards
igor

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