drivers/rtc/interface.c

   1 /*
   2  * RTC subsystem, interface functions
   3  *
   4  * Copyright (C) 2005 Tower Technologies
   5  * Author: Alessandro Zummo <a.zummo@towertech.it>
   6  *
   7  * based on arch/arm/common/rtctime.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/rtc.h>
  15
  16 int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
  17 {
  18         int err;
  19         struct rtc_device *rtc = to_rtc_device(class_dev);
  20
  21         err = mutex_lock_interruptible(&rtc->ops_lock);
  22         if (err)
  23                 return -EBUSY;
  24
  25         if (!rtc->ops)
  26                 err = -ENODEV;
  27         else if (!rtc->ops->read_time)
  28                 err = -EINVAL;
  29         else {
  30                 memset(tm, 0, sizeof(struct rtc_time));
  31                 err = rtc->ops->read_time(class_dev->dev, tm);
  32         }
  33
  34         mutex_unlock(&rtc->ops_lock);
  35         return err;
  36 }
  37 EXPORT_SYMBOL_GPL(rtc_read_time);
  38
  39 int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
  40 {
  41         int err;
  42         struct rtc_device *rtc = to_rtc_device(class_dev);
  43
  44         err = rtc_valid_tm(tm);
  45         if (err != 0)
  46                 return err;
  47
  48         err = mutex_lock_interruptible(&rtc->ops_lock);
  49         if (err)
  50                 return -EBUSY;
  51
  52         if (!rtc->ops)
  53                 err = -ENODEV;
  54         else if (!rtc->ops->set_time)
  55                 err = -EINVAL;
  56         else
  57                 err = rtc->ops->set_time(class_dev->dev, tm);
  58
  59         mutex_unlock(&rtc->ops_lock);
  60         return err;
  61 }
  62 EXPORT_SYMBOL_GPL(rtc_set_time);
  63
  64 int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
  65 {
  66         int err;
  67         struct rtc_device *rtc = to_rtc_device(class_dev);
  68
  69         err = mutex_lock_interruptible(&rtc->ops_lock);
  70         if (err)
  71                 return -EBUSY;
  72
  73         if (!rtc->ops)
  74                 err = -ENODEV;
  75         else if (rtc->ops->set_mmss)
  76                 err = rtc->ops->set_mmss(class_dev->dev, secs);
  77         else if (rtc->ops->read_time && rtc->ops->set_time) {
  78                 struct rtc_time new, old;
  79
  80                 err = rtc->ops->read_time(class_dev->dev, &old);
  81                 if (err == 0) {
  82                         rtc_time_to_tm(secs, &new);
  83
  84                         /*
  85                          * avoid writing when we're going to change the day of
  86                          * the month. We will retry in the next minute. This
  87                          * basically means that if the RTC must not drift
  88                          * by more than 1 minute in 11 minutes.
  89                          */
  90                         if (!((old.tm_hour == 23 && old.tm_min == 59) ||
  91                                 (new.tm_hour == 23 && new.tm_min == 59)))
  92                                 err = rtc->ops->set_time(class_dev->dev, &new);
  93                 }
  94         }
  95         else
  96                 err = -EINVAL;
  97
  98         mutex_unlock(&rtc->ops_lock);
  99
 100         return err;
 101 }
 102 EXPORT_SYMBOL_GPL(rtc_set_mmss);
 103
 104 int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
 105 {
 106         int err;
 107         struct rtc_device *rtc = to_rtc_device(class_dev);
 108
 109         err = mutex_lock_interruptible(&rtc->ops_lock);
 110         if (err)
 111                 return -EBUSY;
 112
 113         if (rtc->ops == NULL)
 114                 err = -ENODEV;
 115         else if (!rtc->ops->read_alarm)
 116                 err = -EINVAL;
 117         else {
 118                 memset(alarm, 0, sizeof(struct rtc_wkalrm));
 119                 err = rtc->ops->read_alarm(class_dev->dev, alarm);
 120         }
 121
 122         mutex_unlock(&rtc->ops_lock);
 123         return err;
 124 }
 125 EXPORT_SYMBOL_GPL(rtc_read_alarm);
 126
 127 int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
 128 {
 129         int err;
 130         struct rtc_device *rtc = to_rtc_device(class_dev);
 131
 132         err = mutex_lock_interruptible(&rtc->ops_lock);
 133         if (err)
 134                 return -EBUSY;
 135
 136         if (!rtc->ops)
 137                 err = -ENODEV;
 138         else if (!rtc->ops->set_alarm)
 139                 err = -EINVAL;
 140         else
 141                 err = rtc->ops->set_alarm(class_dev->dev, alarm);
 142
 143         mutex_unlock(&rtc->ops_lock);
 144         return err;
 145 }
 146 EXPORT_SYMBOL_GPL(rtc_set_alarm);
 147
 148 /**
 149  * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
 150  * @class_dev: the rtc's class device
 151  * @num: how many irqs are being reported (usually one)
 152  * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
 153  * Context: in_interrupt(), irqs blocked
 154  */
 155 void rtc_update_irq(struct class_device *class_dev,
 156                 unsigned long num, unsigned long events)
 157 {
 158         struct rtc_device *rtc = to_rtc_device(class_dev);
 159
 160         spin_lock(&rtc->irq_lock);
 161         rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
 162         spin_unlock(&rtc->irq_lock);
 163
 164         spin_lock(&rtc->irq_task_lock);
 165         if (rtc->irq_task)
 166                 rtc->irq_task->func(rtc->irq_task->private_data);
 167         spin_unlock(&rtc->irq_task_lock);
 168
 169         wake_up_interruptible(&rtc->irq_queue);
 170         kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
 171 }
 172 EXPORT_SYMBOL_GPL(rtc_update_irq);
 173
 174 struct class_device *rtc_class_open(char *name)
 175 {
 176         struct class_device *class_dev = NULL,
 177                                 *class_dev_tmp;
 178
 179         down(&rtc_class->sem);
 180         list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
 181                 if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
 182                         class_dev = class_dev_tmp;
 183                         break;
 184                 }
 185         }
 186
 187         if (class_dev) {
 188                 if (!try_module_get(to_rtc_device(class_dev)->owner))
 189                         class_dev = NULL;
 190         }
 191         up(&rtc_class->sem);
 192
 193         return class_dev;
 194 }
 195 EXPORT_SYMBOL_GPL(rtc_class_open);
 196
 197 void rtc_class_close(struct class_device *class_dev)
 198 {
 199         module_put(to_rtc_device(class_dev)->owner);
 200 }
 201 EXPORT_SYMBOL_GPL(rtc_class_close);
 202
 203 int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
 204 {
 205         int retval = -EBUSY;
 206         struct rtc_device *rtc = to_rtc_device(class_dev);
 207
 208         if (task == NULL || task->func == NULL)
 209                 return -EINVAL;
 210
 211         spin_lock_irq(&rtc->irq_task_lock);
 212         if (rtc->irq_task == NULL) {
 213                 rtc->irq_task = task;
 214                 retval = 0;
 215         }
 216         spin_unlock_irq(&rtc->irq_task_lock);
 217
 218         return retval;
 219 }
 220 EXPORT_SYMBOL_GPL(rtc_irq_register);
 221
 222 void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
 223 {
 224         struct rtc_device *rtc = to_rtc_device(class_dev);
 225
 226         spin_lock_irq(&rtc->irq_task_lock);
 227         if (rtc->irq_task == task)
 228                 rtc->irq_task = NULL;
 229         spin_unlock_irq(&rtc->irq_task_lock);
 230 }
 231 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
 232
 233 int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
 234 {
 235         int err = 0;
 236         unsigned long flags;
 237         struct rtc_device *rtc = to_rtc_device(class_dev);
 238
 239         if (rtc->ops->irq_set_state == NULL)
 240                 return -ENXIO;
 241
 242         spin_lock_irqsave(&rtc->irq_task_lock, flags);
 243         if (rtc->irq_task != task)
 244                 err = -ENXIO;
 245         spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 246
 247         if (err == 0)
 248                 err = rtc->ops->irq_set_state(class_dev->dev, enabled);
 249
 250         return err;
 251 }
 252 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
 253
 254 int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
 255 {
 256         int err = 0;
 257         unsigned long flags;
 258         struct rtc_device *rtc = to_rtc_device(class_dev);
 259
 260         if (rtc->ops->irq_set_freq == NULL)
 261                 return -ENXIO;
 262
 263         spin_lock_irqsave(&rtc->irq_task_lock, flags);
 264         if (rtc->irq_task != task)
 265                 err = -ENXIO;
 266         spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 267
 268         if (err == 0) {
 269                 err = rtc->ops->irq_set_freq(class_dev->dev, freq);
 270                 if (err == 0)
 271                         rtc->irq_freq = freq;
 272         }
 273         return err;
 274 }
 275 EXPORT_SYMBOL_GPL(rtc_irq_set_freq);