sound/pci/ac97/ac97_bus.c

   1 /*
   2  * Linux driver model AC97 bus interface
   3  *
   4  * Author:      Nicolas Pitre
   5  * Created:     Jan 14, 2005
   6  * Copyright:   (C) MontaVista Software Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/device.h>
  17 #include <linux/string.h>
  18
  19 /*
  20  * Let drivers decide whether they want to support given codec from their
  21  * probe method.  Drivers have direct access to the ac97_t structure and may
  22  * decide based on the id field amongst other things.
  23  */
  24 static int ac97_bus_match(struct device *dev, struct device_driver *drv)
  25 {
  26         return 1;
  27 }
  28
  29 static int ac97_bus_suspend(struct device *dev, pm_message_t state)
  30 {
  31         int ret = 0;
  32
  33         if (dev->driver && dev->driver->suspend) {
  34                 ret = dev->driver->suspend(dev, state, SUSPEND_DISABLE);
  35                 if (ret == 0)
  36                         ret = dev->driver->suspend(dev, state, SUSPEND_SAVE_STATE);
  37                 if (ret == 0)
  38                         ret = dev->driver->suspend(dev, state, SUSPEND_POWER_DOWN);
  39         }
  40         return ret;
  41 }
  42
  43 static int ac97_bus_resume(struct device *dev)
  44 {
  45         int ret = 0;
  46
  47         if (dev->driver && dev->driver->resume) {
  48                 ret = dev->driver->resume(dev, RESUME_POWER_ON);
  49                 if (ret == 0)
  50                         ret = dev->driver->resume(dev, RESUME_RESTORE_STATE);
  51                 if (ret == 0)
  52                         ret = dev->driver->resume(dev, RESUME_ENABLE);
  53         }
  54         return ret;
  55 }
  56
  57 struct bus_type ac97_bus_type = {
  58         .name           = "ac97",
  59         .match          = ac97_bus_match,
  60         .suspend        = ac97_bus_suspend,
  61         .resume         = ac97_bus_resume,
  62 };
  63
  64 static int __init ac97_bus_init(void)
  65 {
  66         return bus_register(&ac97_bus_type);
  67 }
  68
  69 subsys_initcall(ac97_bus_init);
  70
  71 static void __exit ac97_bus_exit(void)
  72 {
  73         bus_unregister(&ac97_bus_type);
  74 }
  75
  76 module_exit(ac97_bus_exit);
  77
  78 EXPORT_SYMBOL(ac97_bus_type);
  79
  80 MODULE_LICENSE("GPL");