// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Dummy IRQ handler driver.
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*
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* This module only registers itself as a handler that is specified to it
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* by the 'irq' parameter.
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*
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* The sole purpose of this module is to help with debugging of systems on
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* which spurious IRQs would happen on disabled IRQ vector.
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*
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* Copyright (C) 2013 Jiri Kosina
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*/
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#include <linux/module.h>
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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static int irq = -1;
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static irqreturn_t dummy_interrupt(int irq, void *dev_id)
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{
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static int count = 0;
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if (count == 0) {
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printk(KERN_INFO "dummy-irq: interrupt occurred on IRQ %d\n",
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irq);
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count++;
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}
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return IRQ_NONE;
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}
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static int __init dummy_irq_init(void)
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{
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if (irq < 0) {
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printk(KERN_ERR "dummy-irq: no IRQ given. Use irq=N\n");
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return -EIO;
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}
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if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) {
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printk(KERN_ERR "dummy-irq: cannot register IRQ %d\n", irq);
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return -EIO;
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}
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printk(KERN_INFO "dummy-irq: registered for IRQ %d\n", irq);
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return 0;
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}
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static void __exit dummy_irq_exit(void)
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{
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printk(KERN_INFO "dummy-irq unloaded\n");
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free_irq(irq, &irq);
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}
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module_init(dummy_irq_init);
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module_exit(dummy_irq_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Jiri Kosina");
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module_param_hw(irq, uint, irq, 0444);
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MODULE_PARM_DESC(irq, "The IRQ to register for");
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MODULE_DESCRIPTION("Dummy IRQ handler driver");
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