Hi,

 

Can anyone tell why I cant export PH3 as gpio?

It is the default "usb2_vbus-supply" for usb2 of allwinner A20.

 

In my application I need to control this "usb2_vbus-supply".

 

Example : exporting PH3

 

root@cubieboard2:~# echo 227 > /sys/class/gpio/export                                                                                                              
-bash: echo: write error: Device or resource busy

 

Im using armbian vanilla for my cb2.

 

Thanks in advance.

PH3 is defined in sunxi-common-regulators.dtsi and used in sun7i-a20-cubieboard2.dts to define usb2_vbus-supply. I would suspect without changing these definitions you won't be able to switch the pin on/off from userspace?

Hello Thomas,

 

You're correct, after some modification in sunxi-common-regulators.dtsi and sun7i-a20-cubieboard2.dts, I can now control PH3 to be use in my application.

 

Thanks.