insmod error "unknown symbol in module"

Question

I am writing parallel LED board driver, .ko is successfully generated.

I am facing this issue

[63722.594233] led: Unknown symbol parport_register_device (err 0)

[63722.594264] led: Unknown symbol parport_register_driver (err 0)

Answer 1

parport_register_device is exported in drivers/parport/share.c. So you have to load parport driver first (modprobe parport) and then your driver.