hi there...

i'm writing a linux driver that should read data from a device and send it to the user space. the device will generate an interrupt (irq) indicating that the data is ready. the problem is that the device doesn't exist yet and, in the meantime, i have to simulate it with a program that writes data in the driver, making it (the driver) generate the irq.
does anyone know how to make a driver generate an interrupt when i write data in it? i want to avoid using queues to wake up the reader tasks.

thanks,
cardias.

You can't (as far as I know). IRQs are a voltage level on a wire, and they tend to be rather like inputs in nature.

However, you can wire together two pins of the parallel port (say, connecting the data pin bit 0 to the interrupt pin). You can then trigger an interrupt just by writing to that data pin. Probably a good idea to use a series resistor to prevent you from blowing up the port as well, and you're limited to whichever IRQ line the parallel port is connected to (see /proc/irq), but it should work (after you enable parallel port IRQs in the status register).

See http://www.tldp.org/HOWTO/IO-Port-Pr...g-6.html#ss6.1 for more.

hi cardias;

have a look at chapter 9 from Linux Device Drivers which explains the interrupt handling.The electronic version is at http://www.xml.com/ldd/chapter/book/ch09.html .

good luck