How to change clock in linux-imx

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How to change clock in linux-imx

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asmaa
Contributor IV

Hello All,

I want to understand how  the clock is setup in imx6ul in uboot and linux-imx. 

Following are my questions?

1. When I ran the command below -

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

I get the value - 5280000 is it the ARM_PPL value or system PLL value?

2. I want to set following values in CCM

SIM_PRE_CLK_SEL = 101 => PLL3 PFD2 = 508.2MHzSIM_PODF        = 001 => divide by 2.SIM_CLK_SEL     = 000 => derive clock from pre-muxed SIM clock

How can I set it and which is the ideal place to set this value after linux has booted?

Regards,

Asma

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joanxie
NXP TechSupport
NXP TechSupport

1. When I ran the command below -

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

I get the value - 5280000 is it the ARM_PPL value or system PLL value?

> refer to the imx6ul referen manual, 528M is from PLL2 which is system PLL

2. you can refer to the driver source code as below:

imx6q-cpufreq.c\cpufreq\drivers - linux-imx - i.MX Linux kernel 

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