The "documentation" for
Info: Initiates a shutdown when GPIO pin changes. The given GPIO pin
is configured as an input key that generates KEY_POWER events.
This event is handled by systemd-logind by initiating a
shutdown. Systemd versions older than 225 need an udev rule
enable listening to the input device:
ACTION!="REMOVE", SUBSYSTEM=="input", KERNEL=="event*", \
SUBSYSTEMS=="platform", DRIVERS=="gpio-keys", \
This overlay only handles shutdown. After shutdown, the system
can be powered up again by driving GPIO3 low. The default
configuration uses GPIO3 with a pullup, so if you connect a
button between GPIO3 and GND (pin 5 and 6 on the 40-pin header),
you get a shutdown and power-up button.
Params: gpio_pin GPIO pin to trigger on (default 3)
active_low When this is 1 (active low), a falling
edge generates a key down event and a
rising edge generates a key up event.
When this is 0 (active high), this is
reversed. The default is 1 (active low).
gpio_pull Desired pull-up/down state (off, down, up)
Default is "up".
Note that the default pin (GPIO3) has an
debounce Specify the debounce interval in milliseconds
I have used
gpio-shutdown to implement a shutdown button (although I use GPIO5 - pin 29 as I use the default for I²C).
The "documentation" does not explain what happens in another pin is used - it does state "This overlay only handles shutdown".
Pin 5 USED to perform a restart on older Pi - See Will pulling pin 5 low will make the pi boot up again
but this does not seem to work.
Update Pin 5 WILL restart;
gpio-poweroff had disabled it.
Info: Drives a GPIO high or low on poweroff (including halt). Enabling this
overlay will prevent the ability to boot by driving GPIO3 low.
Indeed there seems to be little point in modern 40 pin Pi - which have a dedicated
Run input which can be used to restart the Pi.
PS If you are using the default
,active_low=1,gpio_pull=up seems unnecessary as there is an external pullup, and active_low is the default.