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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Dummy IRQ handler driver.4 *5 * This module only registers itself as a handler that is specified to it6 * by the 'irq' parameter.7 *8 * The sole purpose of this module is to help with debugging of systems on9 * which spurious IRQs would happen on disabled IRQ vector.10 *11 * Copyright (C) 2013 Jiri Kosina12 */13 14#include <linux/module.h>15#include <linux/irq.h>16#include <linux/interrupt.h>17 18static int irq = -1;19 20static irqreturn_t dummy_interrupt(int irq, void *dev_id)21{22 static int count = 0;23 24 if (count == 0) {25 printk(KERN_INFO "dummy-irq: interrupt occurred on IRQ %d\n",26 irq);27 count++;28 }29 30 return IRQ_NONE;31}32 33static int __init dummy_irq_init(void)34{35 if (irq < 0) {36 printk(KERN_ERR "dummy-irq: no IRQ given. Use irq=N\n");37 return -EIO;38 }39 if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) {40 printk(KERN_ERR "dummy-irq: cannot register IRQ %d\n", irq);41 return -EIO;42 }43 printk(KERN_INFO "dummy-irq: registered for IRQ %d\n", irq);44 return 0;45}46 47static void __exit dummy_irq_exit(void)48{49 printk(KERN_INFO "dummy-irq unloaded\n");50 free_irq(irq, &irq);51}52 53module_init(dummy_irq_init);54module_exit(dummy_irq_exit);55 56MODULE_LICENSE("GPL");57MODULE_AUTHOR("Jiri Kosina");58module_param_hw(irq, uint, irq, 0444);59MODULE_PARM_DESC(irq, "The IRQ to register for");60MODULE_DESCRIPTION("Dummy IRQ handler driver");61