drivers/rtc/class.c

   1 /*
   2  * RTC subsystem, base class
   3  *
   4  * Copyright (C) 2005 Tower Technologies
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  *
   7  * class skeleton from drivers/hwmon/hwmon.c
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/module.h>
  15 #include <linux/rtc.h>
  16 #include <linux/kdev_t.h>
  17 #include <linux/idr.h>
  18 #include <linux/slab.h>
  19 #include <linux/workqueue.h>
  20
  21 #include "rtc-core.h"
  22
  23
  24 static DEFINE_IDR(rtc_idr);
  25 static DEFINE_MUTEX(idr_lock);
  26 struct class *rtc_class;
  27
  28 static void rtc_device_release(struct device *dev)
  29 {
  30         struct rtc_device *rtc = to_rtc_device(dev);
  31         mutex_lock(&idr_lock);
  32         idr_remove(&rtc_idr, rtc->id);
  33         mutex_unlock(&idr_lock);
  34         kfree(rtc);
  35 }
  36
  37 #if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
  38
  39 /*
  40  * On suspend(), measure the delta between one RTC and the
  41  * system's wall clock; restore it on resume().
  42  */
  43
  44 static time_t           oldtime;
  45 static struct timespec  oldts;
  46
  47 static int rtc_suspend(struct device *dev, pm_message_t mesg)
  48 {
  49         struct rtc_device       *rtc = to_rtc_device(dev);
  50         struct rtc_time         tm;
  51
  52         if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
  53                 return 0;
  54
  55         rtc_read_time(rtc, &tm);
  56         ktime_get_ts(&oldts);
  57         rtc_tm_to_time(&tm, &oldtime);
  58
  59         return 0;
  60 }
  61
  62 static int rtc_resume(struct device *dev)
  63 {
  64         struct rtc_device       *rtc = to_rtc_device(dev);
  65         struct rtc_time         tm;
  66         time_t                  newtime;
  67         struct timespec         time;
  68         struct timespec         newts;
  69
  70         if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
  71                 return 0;
  72
  73         ktime_get_ts(&newts);
  74         rtc_read_time(rtc, &tm);
  75         if (rtc_valid_tm(&tm) != 0) {
  76                 pr_debug("%s:  bogus resume time\n", dev_name(&rtc->dev));
  77                 return 0;
  78         }
  79         rtc_tm_to_time(&tm, &newtime);
  80         if (newtime <= oldtime) {
  81                 if (newtime < oldtime)
  82                         pr_debug("%s:  time travel!\n", dev_name(&rtc->dev));
  83                 return 0;
  84         }
  85         /* calculate the RTC time delta */
  86         set_normalized_timespec(&time, newtime - oldtime, 0);
  87
  88         /* subtract kernel time between rtc_suspend to rtc_resume */
  89         time = timespec_sub(time, timespec_sub(newts, oldts));
  90
  91         timekeeping_inject_sleeptime(&time);
  92         return 0;
  93 }
  94
  95 #else
  96 #define rtc_suspend     NULL
  97 #define rtc_resume      NULL
  98 #endif
  99
 100
 101 /**
 102  * rtc_device_register - register w/ RTC class
 103  * @dev: the device to register
 104  *
 105  * rtc_device_unregister() must be called when the class device is no
 106  * longer needed.
 107  *
 108  * Returns the pointer to the new struct class device.
 109  */
 110 struct rtc_device *rtc_device_register(const char *name, struct device *dev,
 111                                         const struct rtc_class_ops *ops,
 112                                         struct module *owner)
 113 {
 114         struct rtc_device *rtc;
 115         struct rtc_wkalrm alrm;
 116         int id, err;
 117
 118         if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
 119                 err = -ENOMEM;
 120                 goto exit;
 121         }
 122
 123
 124         mutex_lock(&idr_lock);
 125         err = idr_get_new(&rtc_idr, NULL, &id);
 126         mutex_unlock(&idr_lock);
 127
 128         if (err < 0)
 129                 goto exit;
 130
 131         id = id & MAX_ID_MASK;
 132
 133         rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
 134         if (rtc == NULL) {
 135                 err = -ENOMEM;
 136                 goto exit_idr;
 137         }
 138
 139         rtc->id = id;
 140         rtc->ops = ops;
 141         rtc->owner = owner;
 142         rtc->irq_freq = 1;
 143         rtc->max_user_freq = 64;
 144         rtc->dev.parent = dev;
 145         rtc->dev.class = rtc_class;
 146         rtc->dev.release = rtc_device_release;
 147
 148         mutex_init(&rtc->ops_lock);
 149         spin_lock_init(&rtc->irq_lock);
 150         spin_lock_init(&rtc->irq_task_lock);
 151         init_waitqueue_head(&rtc->irq_queue);
 152
 153         /* Init timerqueue */
 154         timerqueue_init_head(&rtc->timerqueue);
 155         INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
 156         /* Init aie timer */
 157         rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
 158         /* Init uie timer */
 159         rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
 160         /* Init pie timer */
 161         hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 162         rtc->pie_timer.function = rtc_pie_update_irq;
 163         rtc->pie_enabled = 0;
 164
 165         /* Check to see if there is an ALARM already set in hw */
 166         err = __rtc_read_alarm(rtc, &alrm);
 167
 168         if (!err && !rtc_valid_tm(&alrm.time))
 169                 rtc_initialize_alarm(rtc, &alrm);
 170
 171         strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
 172         dev_set_name(&rtc->dev, "rtc%d", id);
 173
 174         rtc_dev_prepare(rtc);
 175
 176         err = device_register(&rtc->dev);
 177         if (err) {
 178                 put_device(&rtc->dev);
 179                 goto exit_kfree;
 180         }
 181
 182         rtc_dev_add_device(rtc);
 183         rtc_sysfs_add_device(rtc);
 184         rtc_proc_add_device(rtc);
 185
 186         dev_info(dev, "rtc core: registered %s as %s\n",
 187                         rtc->name, dev_name(&rtc->dev));
 188
 189         return rtc;
 190
 191 exit_kfree:
 192         kfree(rtc);
 193
 194 exit_idr:
 195         mutex_lock(&idr_lock);
 196         idr_remove(&rtc_idr, id);
 197         mutex_unlock(&idr_lock);
 198
 199 exit:
 200         dev_err(dev, "rtc core: unable to register %s, err = %d\n",
 201                         name, err);
 202         return ERR_PTR(err);
 203 }
 204 EXPORT_SYMBOL_GPL(rtc_device_register);
 205
 206
 207 /**
 208  * rtc_device_unregister - removes the previously registered RTC class device
 209  *
 210  * @rtc: the RTC class device to destroy
 211  */
 212 void rtc_device_unregister(struct rtc_device *rtc)
 213 {
 214         if (get_device(&rtc->dev) != NULL) {
 215                 mutex_lock(&rtc->ops_lock);
 216                 /* remove innards of this RTC, then disable it, before
 217                  * letting any rtc_class_open() users access it again
 218                  */
 219                 rtc_sysfs_del_device(rtc);
 220                 rtc_dev_del_device(rtc);
 221                 rtc_proc_del_device(rtc);
 222                 device_unregister(&rtc->dev);
 223                 rtc->ops = NULL;
 224                 mutex_unlock(&rtc->ops_lock);
 225                 put_device(&rtc->dev);
 226         }
 227 }
 228 EXPORT_SYMBOL_GPL(rtc_device_unregister);
 229
 230 static int __init rtc_init(void)
 231 {
 232         rtc_class = class_create(THIS_MODULE, "rtc");
 233         if (IS_ERR(rtc_class)) {
 234                 printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
 235                 return PTR_ERR(rtc_class);
 236         }
 237         rtc_class->suspend = rtc_suspend;
 238         rtc_class->resume = rtc_resume;
 239         rtc_dev_init();
 240         rtc_sysfs_init(rtc_class);
 241         return 0;
 242 }
 243
 244 static void __exit rtc_exit(void)
 245 {
 246         rtc_dev_exit();
 247         class_destroy(rtc_class);
 248         idr_destroy(&rtc_idr);
 249 }
 250
 251 subsys_initcall(rtc_init);
 252 module_exit(rtc_exit);
 253
 254 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
 255 MODULE_DESCRIPTION("RTC class support");
 256 MODULE_LICENSE("GPL");