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 void rtc_update_irq(struct class_device *class_dev,
 149                 unsigned long num, unsigned long events)
 150 {
 151         struct rtc_device *rtc = to_rtc_device(class_dev);
 152
 153         spin_lock(&rtc->irq_lock);
 154         rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
 155         spin_unlock(&rtc->irq_lock);
 156
 157         spin_lock(&rtc->irq_task_lock);
 158         if (rtc->irq_task)
 159                 rtc->irq_task->func(rtc->irq_task->private_data);
 160         spin_unlock(&rtc->irq_task_lock);
 161
 162         wake_up_interruptible(&rtc->irq_queue);
 163         kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
 164 }
 165 EXPORT_SYMBOL_GPL(rtc_update_irq);
 166
 167 struct class_device *rtc_class_open(char *name)
 168 {
 169         struct class_device *class_dev = NULL,
 170                                 *class_dev_tmp;
 171
 172         down(&rtc_class->sem);
 173         list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
 174                 if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
 175                         class_dev = class_dev_tmp;
 176                         break;
 177                 }
 178         }
 179
 180         if (class_dev) {
 181                 if (!try_module_get(to_rtc_device(class_dev)->owner))
 182                         class_dev = NULL;
 183         }
 184         up(&rtc_class->sem);
 185
 186         return class_dev;
 187 }
 188 EXPORT_SYMBOL_GPL(rtc_class_open);
 189
 190 void rtc_class_close(struct class_device *class_dev)
 191 {
 192         module_put(to_rtc_device(class_dev)->owner);
 193 }
 194 EXPORT_SYMBOL_GPL(rtc_class_close);
 195
 196 int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
 197 {
 198         int retval = -EBUSY;
 199         struct rtc_device *rtc = to_rtc_device(class_dev);
 200
 201         if (task == NULL || task->func == NULL)
 202                 return -EINVAL;
 203
 204         spin_lock(&rtc->irq_task_lock);
 205         if (rtc->irq_task == NULL) {
 206                 rtc->irq_task = task;
 207                 retval = 0;
 208         }
 209         spin_unlock(&rtc->irq_task_lock);
 210
 211         return retval;
 212 }
 213 EXPORT_SYMBOL_GPL(rtc_irq_register);
 214
 215 void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
 216 {
 217         struct rtc_device *rtc = to_rtc_device(class_dev);
 218
 219         spin_lock(&rtc->irq_task_lock);
 220         if (rtc->irq_task == task)
 221                 rtc->irq_task = NULL;
 222         spin_unlock(&rtc->irq_task_lock);
 223 }
 224 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
 225
 226 int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
 227 {
 228         int err = 0;
 229         unsigned long flags;
 230         struct rtc_device *rtc = to_rtc_device(class_dev);
 231
 232         spin_lock_irqsave(&rtc->irq_task_lock, flags);
 233         if (rtc->irq_task != task)
 234                 err = -ENXIO;
 235         spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 236
 237         if (err == 0)
 238                 err = rtc->ops->irq_set_state(class_dev->dev, enabled);
 239
 240         return err;
 241 }
 242 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
 243
 244 int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
 245 {
 246         int err = 0, tmp = 0;
 247         unsigned long flags;
 248         struct rtc_device *rtc = to_rtc_device(class_dev);
 249
 250         /* allowed range is 2-8192 */
 251         if (freq < 2 || freq > 8192)
 252                 return -EINVAL;
 253 /*
 254         FIXME: this does not belong here, will move where appropriate
 255         at a later stage. It cannot hurt right now, trust me :)
 256         if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
 257                 return -EACCES;
 258 */
 259         /* check if freq is a power of 2 */
 260         while (freq > (1 << tmp))
 261                 tmp++;
 262
 263         if (freq != (1 << tmp))
 264                 return -EINVAL;
 265
 266         spin_lock_irqsave(&rtc->irq_task_lock, flags);
 267         if (rtc->irq_task != task)
 268                 err = -ENXIO;
 269         spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 270
 271         if (err == 0) {
 272                 err = rtc->ops->irq_set_freq(class_dev->dev, freq);
 273                 if (err == 0)
 274                         rtc->irq_freq = freq;
 275         }
 276         return err;
 277 }