GPIO's connectcore 9c

Question

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.

Thanks!!!

Answer 1

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

Answer 2

Hi,
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.