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drivers/misc/dummy-irq.c 1.51 KB
81f7e3824   Eric Lee   Initial Release, ...
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  /*
   * Dummy IRQ handler driver.
   *
   * This module only registers itself as a handler that is specified to it
   * by the 'irq' parameter.
   *
   * The sole purpose of this module is to help with debugging of systems on
   * which spurious IRQs would happen on disabled IRQ vector.
   *
   * Copyright (C) 2013 Jiri Kosina
   */
  
  /*
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published by
   * the Free Software Foundation.
   */
  #include <linux/module.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>
  
  static int irq = -1;
  
  static irqreturn_t dummy_interrupt(int irq, void *dev_id)
  {
  	static int count = 0;
  
  	if (count == 0) {
  		printk(KERN_INFO "dummy-irq: interrupt occurred on IRQ %d
  ",
  				irq);
  		count++;
  	}
  
  	return IRQ_NONE;
  }
  
  static int __init dummy_irq_init(void)
  {
  	if (irq < 0) {
  		printk(KERN_ERR "dummy-irq: no IRQ given.  Use irq=N
  ");
  		return -EIO;
  	}
  	if (request_irq(irq, &dummy_interrupt, IRQF_SHARED, "dummy_irq", &irq)) {
  		printk(KERN_ERR "dummy-irq: cannot register IRQ %d
  ", irq);
  		return -EIO;
  	}
  	printk(KERN_INFO "dummy-irq: registered for IRQ %d
  ", irq);
  	return 0;
  }
  
  static void __exit dummy_irq_exit(void)
  {
  	printk(KERN_INFO "dummy-irq unloaded
  ");
  	free_irq(irq, &irq);
  }
  
  module_init(dummy_irq_init);
  module_exit(dummy_irq_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Jiri Kosina");
  module_param_hw(irq, uint, irq, 0444);
  MODULE_PARM_DESC(irq, "The IRQ to register for");
  MODULE_DESCRIPTION("Dummy IRQ handler driver");