How to change clock in linux-imx

asmaa — Fri, 16 Aug 2019 08:21:27 GMT

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

Re: How to change clock in linux-imx

joanxie — Mon, 19 Aug 2019 08:53:43 GMT

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: