GPIO's connectcore 9c

Hello, I wonder why when I use the interrupt (GPIO [18]) of PCA9554 puts me "open: /dev/gpio/18: Device or resource busy ". I have enabled the serial port C, which has the GPIO [40] that this in turn is related to the GPIO [18] because they have the same interrupt IRQ3, but I don’t think that influence because if not, almost all GPIO would be busy.


How did you create a node for /dev/gpio/18
I think /dev/gpio/18 would apply to GPIO[18] of NS9210 and not to the GPIO of the PCA9554 I2C expander

By GPIO 18, did you means, the Pin 18 of the 9210 module?
If yes, then it correspond to the GPIO 9 (or SCL for I2C):
cme9210 Connector Pin 18 ==> GPIO 9 (SCL).
GPIOs pins handled by the system are declared in the file “etc/makedev.d/cme9210js” (or some name like that). You should check this file. If it contains the GPIO 9 entry, and you have load the “gpio” driver, then this GPIO cannot be use by another driver than the “gpio” one. Hope this help you.