Mastering Linux Kernel Development

Registering an interrupt handler

typedef irqreturn_t (*irq_handler_t)(int, void *);/** * request_irq - allocate an interrupt line * @irq: Interrupt line to allocate * @handler: Function to be called when the IRQ occurs. * @irqflags: Interrupt type flags * @devname: An ascii name for the claiming device * @dev_id: A cookie passed back to the handler function */ int request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,                 const char *name, void *dev);

request_irq() instantiates an irqaction object with values passed as parameters and binds it to the irq_desc specified as the first (irq) parameter. This call allocates interrupt resources and enables the interrupt line and IRQ handling. handler is a function pointer of type