request_irq — allocate an interrupt line
int request_irq ( | unsigned int | irq, |
| irqreturn_t (* | handler)
(int, void *, struct pt_regs *), | |
| unsigned long | irqflags, | |
| const char * | devname, | |
| void * | dev_id); |
irqInterrupt line to allocate
handlerFunction to be called when the IRQ occurs
irqflagsInterrupt type flags
devnameAn ascii name for the claiming device
dev_idA cookie passed back to the handler function
This call allocates interrupt resources and enables the interrupt line and IRQ handling. From the point this call is made your handler function may be invoked. Since your handler function must clear any interrupt the board raises, you must take care both to initialise your hardware and to set up the interrupt handler in the right order.
Dev_id must be globally unique. Normally the address of the device data structure is used as the cookie. Since the handler receives this value it makes sense to use it.
If your interrupt is shared you must pass a non NULL dev_id as this is required when freeing the interrupt.