devm_request_threaded_irq()

Purpose

Registers an interrupt handler with optional threaded bottom-half handling and device-managed cleanup.

Header

#include <linux/interrupt.h>

Prototype

int devm_request_threaded_irq(struct device *dev, unsigned int irq, irq_handler_t handler, irq_handler_t thread_fn, unsigned long irqflags, const char *devname, void *dev_id);

Parameters

• dev: device used for managed cleanup.
• irq: IRQ number.
• handler: top-half handler, or NULL.
• thread_fn: threaded handler.
• irqflags: trigger and sharing flags.
• devname: name shown in interrupt information.
• dev_id: cookie passed to handlers.

Return Value

• Success: returns 0.
• Failure: returns a negative errno value.

Minimal Example

ret = devm_request_threaded_irq(dev, irq, NULL, my_irq_thread,
                                IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                                "mydev", priv);

Common Pitfalls

• Use IRQF_ONESHOT when using only a threaded handler.
• Keep top-half handlers minimal.
• Do not perform slow bus I/O in hard IRQ context.

Related Topics

• Kernel Driver