Gpio # for USB Power?

I am happily using gpio control to toggle power to the external USB port on an AR-300M, and now I’m trying to achieve the same thing on an X750 Spitz.

I found this post from 2016: MiFi external USB 2.0 power where alzhao suggests looking at ‘/sys/class/leds/*:usbpow’ . However on the X750 I see:

X750:/sys/class/leds# ls -1
ath9k-phy1
gl-x750:white:4g
gl-x750:white:power
gl-x750:white:wan
gl-x750:white:wlan2g
gl-x750:white:wlan5g

I don’t know what device ‘ath9k-phy1’ is; it doesn’t seem to toggle USB power. The others are the frontpanel LEDs as expected.

So, is there a recommended way to identify the gpio pin for USB power? Is it in some corner of the documentation I have missed?

Cheers
Sean

its gpio 2

echo 2 >/sys/class/gpio/export
echo out >/sys/class/gpio/gpio2/direction

should power up usb