cant put PZ3 into interrupt mode

[vdl]

gpioinfo output

gpiochip9 - 10 lines:
line 0: "PZ0" input
line 1: "PZ1" input
line 2: "PZ2" input
line 3: "PZ3" input

gpiomon output

# gpiomon --num-events 1 --edges falling PZ0
^C
# gpiomon --num-events 1 --edges falling PZ1
^C
# gpiomon --num-events 1 --edges falling PZ2
^C
# gpiomon --num-events 1 --edges falling PZ3
gpiomon: unable to request lines on chip /dev/gpiochip9: No such device or address

why is there a problem with PZ3 pin specifically? noone is using it

should i add something in dts?

[PatrickF · Accepted solution]

Hi @vdl 

Most probable cause if because you already have another GPIO Px[3] defined as interrupt elsewhere.

This is a general constrains on most STM32 products due to the way the interrupt mux is done wrt GPIOs pins. Please refer to Reference Manual for details.

Regards.

[vdl]

disabled emmc1 ( sd card interface ) which was using PD3 as interrupt - now PZ3 works

weirdly i still can gpiomon PD3 and other Px3 pins ( unused ones )

also i could gpiomon other Px3 before