Where is the correct place for the Zero 2W to put in the gpio-poweroff dtoverlay load command?

General Discussion
1

I’m trying to get my Pi Zero 2W to raise a GPIO pin when powering down.
Nothing appears to be happening - the unit stays externally powered, suggesting my hardware does not detect the raised pin but in this case I would expect after 3s to see a kernal panic raised on the Pi.

I’m assuming that the correct file is /boot/config.txt (a symlink to /boot/firmware/config.txt) and have put the command (“dtoverlay=gpio-poweroff,gpiopin=4”) there.

One other possible cause of issues - my application on the Pi uses diozero java library (https://www.diozero.com/) to handle I2C messages.

Any help appreciated?

2

What command do you use to power down the device? reboot or halt will not assert the pin.

Just to be sure, did you connect the right pin? GPIO 4 is physical pin 7 (https://pinout.xyz/)

And did you activate i2c within dietpi-config?

AI also suggested :sweat_smile:
If the Java library exports GPIO 4 then gpio-poweroff can not take control over this pin. The overlay only works if the pin is unused.

3

I’ve tried “sudo shutdown now” and “poweroff”.

i2c is activated.

i have unmasked systemd-logind.

I don’t access the gpio pins via diozero, just i2c.

the pin assignment is correct - hardware engineer chose and built it.

it’s odd.

I have also installed device-tree-compiler to use dtc to check the device tree which does contain gpio-poweroff.

another weird thing - “dtoverlay -l” gives unknown command error in bash as if not dtoverlay not installed.