USB Host Power-Enable Polarity

I’m developing a carrier board for the Colibri iMX6 processor board. The iMX6 manual shows a sample schematic to control the USB Host Power using a Texas Instruments TPS2052 power switch. This IC uses a positive (logic-high) power enable control signal. The schematic for the Iris carrier board uses a TPS2042 power switch which requires a negative (logic-low) power enable signal. I’m trying to verify which IC I should spec in for my design. I’m planning on using Linux with our iMX6 board. Does anyone know if the Linux USB drivers can adapt to either signal polarity to control the power on my Host USB port?

Yes, the polarity can easily be changed in the Linux device tree.

While the carrier boards for the Colibri family use negative logic the carrier boards for the Apalis family use positive logic for the USB host power enable.

So you can see an example on how to specify both polarities in the respective device tree:

Apalis iMX6
Colibri iMX6

Note that the Apalis device tree has to switch on an additonal regulator which is irrelevant to your question.