1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Dummy IRQ handler driver.
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * This module only registers itself as a handler that is specified to it
6*4882a593Smuzhiyun * by the 'irq' parameter.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * The sole purpose of this module is to help with debugging of systems on
9*4882a593Smuzhiyun * which spurious IRQs would happen on disabled IRQ vector.
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun * Copyright (C) 2013 Jiri Kosina
12*4882a593Smuzhiyun */
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <linux/module.h>
15*4882a593Smuzhiyun #include <linux/irq.h>
16*4882a593Smuzhiyun #include <linux/interrupt.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun static int irq = -1;
19*4882a593Smuzhiyun
dummy_interrupt(int irq,void * dev_id)20*4882a593Smuzhiyun static irqreturn_t dummy_interrupt(int irq, void *dev_id)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun static int count = 0;
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun if (count == 0) {
25*4882a593Smuzhiyun printk(KERN_INFO "dummy-irq: interrupt occurred on IRQ %d\n",
26*4882a593Smuzhiyun irq);
27*4882a593Smuzhiyun count++;
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun return IRQ_NONE;
31*4882a593Smuzhiyun }
32*4882a593Smuzhiyun
dummy_irq_init(void)33*4882a593Smuzhiyun static int __init dummy_irq_init(void)
34*4882a593Smuzhiyun {
35*4882a593Smuzhiyun if (irq < 0) {
36*4882a593Smuzhiyun printk(KERN_ERR "dummy-irq: no IRQ given. Use irq=N\n");
37*4882a593Smuzhiyun return -EIO;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) {
40*4882a593Smuzhiyun printk(KERN_ERR "dummy-irq: cannot register IRQ %d\n", irq);
41*4882a593Smuzhiyun return -EIO;
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun printk(KERN_INFO "dummy-irq: registered for IRQ %d\n", irq);
44*4882a593Smuzhiyun return 0;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
dummy_irq_exit(void)47*4882a593Smuzhiyun static void __exit dummy_irq_exit(void)
48*4882a593Smuzhiyun {
49*4882a593Smuzhiyun printk(KERN_INFO "dummy-irq unloaded\n");
50*4882a593Smuzhiyun free_irq(irq, &irq);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun module_init(dummy_irq_init);
54*4882a593Smuzhiyun module_exit(dummy_irq_exit);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun MODULE_LICENSE("GPL");
57*4882a593Smuzhiyun MODULE_AUTHOR("Jiri Kosina");
58*4882a593Smuzhiyun module_param_hw(irq, uint, irq, 0444);
59*4882a593Smuzhiyun MODULE_PARM_DESC(irq, "The IRQ to register for");
60*4882a593Smuzhiyun MODULE_DESCRIPTION("Dummy IRQ handler driver");
61