drivers/rtc/rtc-generic.c

   1 /* rtc-generic: RTC driver using the generic RTC abstraction
   2  *
   3  * Copyright (C) 2008 Kyle McMartin <kyle@mcmartin.ca>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/time.h>
   9 #include <linux/platform_device.h>
  10
  11 #include <asm/rtc.h>
  12
  13 /* as simple as can be, and no simpler. */
  14 struct generic_rtc {
  15         struct rtc_device *rtc;
  16         spinlock_t lock;
  17 };
  18
  19 static int generic_get_time(struct device *dev, struct rtc_time *tm)
  20 {
  21         struct generic_rtc *p = dev_get_drvdata(dev);
  22         unsigned long flags, ret;
  23
  24         spin_lock_irqsave(&p->lock, flags);
  25         ret = get_rtc_time(tm);
  26         spin_unlock_irqrestore(&p->lock, flags);
  27
  28         if (ret & RTC_BATT_BAD)
  29                 return -EOPNOTSUPP;
  30
  31         return 0;
  32 }
  33
  34 static int generic_set_time(struct device *dev, struct rtc_time *tm)
  35 {
  36         struct generic_rtc *p = dev_get_drvdata(dev);
  37         unsigned long flags;
  38         int ret;
  39
  40         spin_lock_irqsave(&p->lock, flags);
  41         ret = set_rtc_time(tm);
  42         spin_unlock_irqrestore(&p->lock, flags);
  43
  44         if (ret < 0)
  45                 return -EOPNOTSUPP;
  46
  47         return 0;
  48 }
  49
  50 static const struct rtc_class_ops generic_rtc_ops = {
  51         .read_time = generic_get_time,
  52         .set_time = generic_set_time,
  53 };
  54
  55 static int __devinit generic_rtc_probe(struct platform_device *dev)
  56 {
  57         struct generic_rtc *p;
  58
  59         p = kzalloc(sizeof (*p), GFP_KERNEL);
  60         if (!p)
  61                 return -ENOMEM;
  62
  63         spin_lock_init(&p->lock);
  64
  65         p->rtc = rtc_device_register("rtc-generic", &dev->dev,
  66                                      &generic_rtc_ops, THIS_MODULE);
  67         if (IS_ERR(p->rtc)) {
  68                 int err = PTR_ERR(p->rtc);
  69                 kfree(p);
  70                 return err;
  71         }
  72
  73         platform_set_drvdata(dev, p);
  74
  75         return 0;
  76 }
  77
  78 static int __devexit generic_rtc_remove(struct platform_device *dev)
  79 {
  80         struct generic_rtc *p = platform_get_drvdata(dev);
  81
  82         rtc_device_unregister(p->rtc);
  83         kfree(p);
  84
  85         return 0;
  86 }
  87
  88 static struct platform_driver generic_rtc_driver = {
  89         .driver = {
  90                 .name = "rtc-generic",
  91                 .owner = THIS_MODULE,
  92         },
  93         .probe = generic_rtc_probe,
  94         .remove = __devexit_p(generic_rtc_remove),
  95 };
  96
  97 static int __init generic_rtc_init(void)
  98 {
  99         return platform_driver_register(&generic_rtc_driver);
 100 }
 101
 102 static void __exit generic_rtc_fini(void)
 103 {
 104         platform_driver_unregister(&generic_rtc_driver);
 105 }
 106
 107 module_init(generic_rtc_init);
 108 module_exit(generic_rtc_fini);
 109
 110 MODULE_AUTHOR("Kyle McMartin <kyle@mcmartin.ca>");
 111 MODULE_LICENSE("GPL");
 112 MODULE_DESCRIPTION("Generic RTC driver");
 113 MODULE_ALIAS("platform:rtc-generic");