REQUEST_THREADED_IRQ(9)             Public Functions Provided             REQUEST_THREADED_IRQ(9)



NAME
       request_threaded_irq - allocate an interrupt line

SYNOPSIS
       int request_threaded_irq(unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn,
                                unsigned long irqflags, const char * devname, void * dev_id);

ARGUMENTS
       irq
           Interrupt line to allocate

       handler
           Function to be called when the IRQ occurs. Primary handler for threaded interrupts If
           NULL and thread_fn != NULL the default primary handler is installed

       thread_fn
           Function called from the irq handler thread If NULL, no irq thread is created

       irqflags
           Interrupt type flags

       devname
           An ascii name for the claiming device

       dev_id
           A cookie passed back to the handler function

DESCRIPTION
       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.

       If you want to set up a threaded irq handler for your device then you need to supply
       handler and thread_fn.  handler is still called in hard interrupt context and has to check
       whether the interrupt originates from the device. If yes it needs to disable the interrupt
       on the device and return IRQ_WAKE_THREAD which will wake up the handler thread and run
       thread_fn. This split handler design is necessary to support shared interrupts.

       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.

       Flags:

       IRQF_SHARED Interrupt is shared IRQF_TRIGGER_* Specify active edge(s) or level

AUTHORS
       Thomas Gleixner <tglx AT linutronix.de>
           Author.

       Ingo Molnar <mingo AT elte.hu>
           Author.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                   REQUEST_THREADED_IRQ(9)