Using power management on i.MX53 QSB

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Using power management on i.MX53 QSB

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FernandoGinezd1
Contributor II

Hi!

I'm trying to use low power modes using Linux with my QSB. I need to suspend my system and wake up with a USB remote wake-up event.

I've found in the os the options to suspend to RAM and enter Stand-by , but it's seems that everything is stopped (including usb system) because the system wakes up only after pressing power button.

 

Is this the right way to enter low power modes? Does anyone know how to implement a solution using usb wake-up events to return from a low power mode?

 

Thanks in advance!

 

________________________

Fernando Ginez da Silva

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StevenLauridsen
Contributor I

I've found in the os the options to suspend to RAM and enter Stand-by , but it's seems that everything is stopped (including usb system) because the system wakes up only after pressing power button.

 

Please tell me how you did this??

 

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daiane_angolini
NXP Employee
NXP Employee

You can see some instructions on mx53_start_linux.pdf, chapter 6.9, page 6-7.

 

I copy some piece over here, but there is more info on the doc:

 

For otg port:

echo enabled > /sys/devices/platform/fsl-usb2-otg/power/wakeup

 

For device-only port:

echo enabled > /sys/devices/platform/fsl-usb2-udc/power/wakeup

 

For host-only port:

echo enabled > /sys/devices/platform/fsl-ehci.x/power/wakeup

(x is the port num)

 

For usb child device

echo enabled > /sys/bus/usb/devices/1-1/power/wakeup

 

 

You can find this file under package from this link https://www.freescale.com/webapp/Download?colCode=IMX53_QSB_1101_LINUXDOCS_BUNDLE&location=null&fpsp...

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