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Adventurer
Adventurer
12,028 Views
Registered: ‎12-16-2013

Controlling FCLKs in Linux

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Hi all,

 

I am trying to disable Zynq FCLKs in Linux. 

My kernel is 3.13.0-xilinx.

 

I can change the PL clock frequency through software.

Bu when I use the Clock Throttle explained in UG858-Zynq TRM manual

The clock still running.

 

I came accross this page http://www.wiki.xilinx.com/Controlling+FCLKs+in+Linux

But I cannot find the devcfg device node in sysfs to control the FCLK

 

Any kind of help will be appreciated

 

Mohava

 

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Adventurer
Adventurer
11,121 Views
Registered: ‎12-16-2013

Re: Controlling FCLKs in Linux

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Hi, 

I found the solution and the following command helped me to change the frequencies 

 

 

echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo 222223 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
echo 333334 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
echo 666667 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

 

 

mohava

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Adventurer
Adventurer
11,122 Views
Registered: ‎12-16-2013

Re: Controlling FCLKs in Linux

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Hi, 

I found the solution and the following command helped me to change the frequencies 

 

 

echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo 222223 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
echo 333334 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed
echo 666667 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

 

 

mohava

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Adventurer
Adventurer
5,869 Views
Registered: ‎12-16-2013

Re: Controlling FCLKs in Linux

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for able to enable and disable the PL clock I used these command

to make the drivers visible

 

cd /sys/devices/amba.0/f8007000.ps7-dev-cfg
echo fclk0 > fclk_export
cd /sys/devices/amba.0/f8007000.ps7-dev-cfg/fclk/fclk0
echo 1 > set_rate

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Explorer
Explorer
3,460 Views
Registered: ‎11-21-2013

Re: Controlling FCLKs in Linux

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Hi, Mohava,

 

I have same doubts about how to change the frequency for fclk0, fclk1 in linux.  (Linaro Ubuntu on ZC706)

 

And while i have

/sys/devices/soc0/amba/f8007000.devcfg/fclk_export

 

I have fclk0 and fclk1 folders here

/sys/kernel/debug/clk

 

I have no where to find the set_rate,  and enable files inside. 

 

Do you know other ways to set the frequencies?

 

Thank you

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