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idata
Community Manager
1,086 Views

Disable USB power via PSW

Looking at the schematic for the sparkfun base block (and I believe the mini-breakout board), the PSW pin on the edison connects to a MIC2039 to control power to the OTG USB connection. I'm working on a product that needs to disable the USB power. (the device it connects to is not smart enough to suspend correctly)

The above link mentions using echo '1-1' > unbind in /sys/bus/usb/drivers/usb but this does not appear to have any effect. My voltage meter in the usb path still shows 5v. Is there a way I can control the PSW pin to disable USB when needed?

Thanks,

Ryan

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7 Replies
idata
Community Manager
49 Views

Hi Ryan,

 

 

Please let us investigate this case a little bit more, we'll get back to you as soon as we have a more accurate answer.

 

 

Regards,

 

Pablo
idata
Community Manager
49 Views

Thanks Pablo, any help here would be greatly appreciated.

- Ryan

idata
Community Manager
49 Views

Pablo,

Any updates?

Thanks,

Ryan

idata
Community Manager
49 Views

Hi Ryan,

 

 

Thank you for your patience. For the mini-breakout board, as you can see in the schematic in page 6 of the following document http://www.intel.com/content/dam/support/us/en/documents/edison/sb/mini_edison_breakout_hvm_8_26.pdf http://www.intel.com/content/dam/support/us/en/documents/edison/sb/mini_edison_breakout_hvm_8_26.pdf, VCC of the OTG USB is connected to VBUS, the connection needs to be disconnected at the hardware level on the board.

 

 

Regards,

 

Pablo
idata
Community Manager
49 Views

Pablo, so PSW can't be controlled from linux?

idata
Community Manager
49 Views

Hi Ryan,

 

 

It is no longer possible using the bind/unbind command, we also tested it and got the same results as you. We will investigate if there's any other way to control the pin from Linux. But for now, I would suggest you to go on with the hardware method as it is the one that will certainly work.

 

 

Regards,

 

Pablo
idata
Community Manager
49 Views

Pablo,

Thanks for letting me know. Yea, looks like they removed support for that in the linux kernel (not sure why). We're ANDing PSW+a gpio pin on our board that goes to the enable on our usb power, so that should work.

Thanks,

Ryan

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