Linux Device Drivers Development

Registering an interrupt handler

You can register a callback to be run when the interruption (or interrupt line) you are interested in gets fired. You can achieve that with the request_irq() function, declared in <linux/interrupt.h>:

int request_irq(unsigned int irq, irq_handler_t handler, 
    unsigned long flags, const char *name, void *dev) 

request_irq() may fail, and returns 0 on success. Other elements of the preceding code are outlined in detail as follows:

• flags: These should be a bitmask of the masks defined in <linux/interrupt.h>. The most used are:
  • IRQF_TIMER: Informs the kernel that this handler was originated by a system timer interrupt.
  • IRQF_SHARED: Used for interrupt lines that can be shared by two or more devices. Each device ...