include/linux/rtc.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Generic RTC interface.
   4  * This version contains the part of the user interface to the Real Time Clock
   5  * service. It is used with both the legacy mc146818 and also  EFI
   6  * Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
   7  * from <linux/mc146818rtc.h> to this file for 2.4 kernels.
   8  *
   9  * Copyright (C) 1999 Hewlett-Packard Co.
  10  * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
  11  */
  12 #ifndef _LINUX_RTC_H_
  13 #define _LINUX_RTC_H_
  14
  15
  16 #include <linux/types.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/nvmem-provider.h>
  19 #include <uapi/linux/rtc.h>
  20
  21 extern int rtc_month_days(unsigned int month, unsigned int year);
  22 extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
  23 extern int rtc_valid_tm(struct rtc_time *tm);
  24 extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
  25 extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
  26 ktime_t rtc_tm_to_ktime(struct rtc_time tm);
  27 struct rtc_time rtc_ktime_to_tm(ktime_t kt);
  28
  29 /*
  30  * rtc_tm_sub - Return the difference in seconds.
  31  */
  32 static inline time64_t rtc_tm_sub(struct rtc_time *lhs, struct rtc_time *rhs)
  33 {
  34         return rtc_tm_to_time64(lhs) - rtc_tm_to_time64(rhs);
  35 }
  36
  37 #include <linux/device.h>
  38 #include <linux/seq_file.h>
  39 #include <linux/cdev.h>
  40 #include <linux/poll.h>
  41 #include <linux/mutex.h>
  42 #include <linux/timerqueue.h>
  43 #include <linux/workqueue.h>
  44
  45 extern const struct class rtc_class;
  46
  47 /*
  48  * For these RTC methods the device parameter is the physical device
  49  * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
  50  * was passed to rtc_device_register().  Its driver_data normally holds
  51  * device state, including the rtc_device pointer for the RTC.
  52  *
  53  * Most of these methods are called with rtc_device.ops_lock held,
  54  * through the rtc_*(struct rtc_device *, ...) calls.
  55  *
  56  * The (current) exceptions are mostly filesystem hooks:
  57  *   - the proc() hook for procfs
  58  */
  59 struct rtc_class_ops {
  60         int (*ioctl)(struct device *, unsigned int, unsigned long);
  61         int (*read_time)(struct device *, struct rtc_time *);
  62         int (*set_time)(struct device *, struct rtc_time *);
  63         int (*read_alarm)(struct device *, struct rtc_wkalrm *);
  64         int (*set_alarm)(struct device *, struct rtc_wkalrm *);
  65         int (*proc)(struct device *, struct seq_file *);
  66         int (*alarm_irq_enable)(struct device *, unsigned int enabled);
  67         int (*read_offset)(struct device *, long *offset);
  68         int (*set_offset)(struct device *, long offset);
  69         int (*param_get)(struct device *, struct rtc_param *param);
  70         int (*param_set)(struct device *, struct rtc_param *param);
  71 };
  72
  73 struct rtc_device;
  74
  75 struct rtc_timer {
  76         struct timerqueue_node node;
  77         ktime_t period;
  78         void (*func)(struct rtc_device *rtc);
  79         struct rtc_device *rtc;
  80         int enabled;
  81 };
  82
  83 /* flags */
  84 #define RTC_DEV_BUSY 0
  85 #define RTC_NO_CDEV  1
  86
  87 struct rtc_device {
  88         struct device dev;
  89         struct module *owner;
  90
  91         int id;
  92
  93         const struct rtc_class_ops *ops;
  94         struct mutex ops_lock;
  95
  96         struct cdev char_dev;
  97         unsigned long flags;
  98
  99         unsigned long irq_data;
 100         spinlock_t irq_lock;
 101         wait_queue_head_t irq_queue;
 102         struct fasync_struct *async_queue;
 103
 104         int irq_freq;
 105         int max_user_freq;
 106
 107         struct timerqueue_head timerqueue;
 108         struct rtc_timer aie_timer;
 109         struct rtc_timer uie_rtctimer;
 110         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
 111         int pie_enabled;
 112         struct work_struct irqwork;
 113
 114         /*
 115          * This offset specifies the update timing of the RTC.
 116          *
 117          * tsched     t1 write(t2.tv_sec - 1sec))  t2 RTC increments seconds
 118          *
 119          * The offset defines how tsched is computed so that the write to
 120          * the RTC (t2.tv_sec - 1sec) is correct versus the time required
 121          * for the transport of the write and the time which the RTC needs
 122          * to increment seconds the first time after the write (t2).
 123          *
 124          * For direct accessible RTCs tsched ~= t1 because the write time
 125          * is negligible. For RTCs behind slow busses the transport time is
 126          * significant and has to be taken into account.
 127          *
 128          * The time between the write (t1) and the first increment after
 129          * the write (t2) is RTC specific. For a MC146818 RTC it's 500ms,
 130          * for many others it's exactly 1 second. Consult the datasheet.
 131          *
 132          * The value of this offset is also used to calculate the to be
 133          * written value (t2.tv_sec - 1sec) at tsched.
 134          *
 135          * The default value for this is NSEC_PER_SEC + 10 msec default
 136          * transport time. The offset can be adjusted by drivers so the
 137          * calculation for the to be written value at tsched becomes
 138          * correct:
 139          *
 140          *      newval = tsched + set_offset_nsec - NSEC_PER_SEC
 141          * and  (tsched + set_offset_nsec) % NSEC_PER_SEC == 0
 142          */
 143         unsigned long set_offset_nsec;
 144
 145         unsigned long features[BITS_TO_LONGS(RTC_FEATURE_CNT)];
 146
 147         time64_t range_min;
 148         timeu64_t range_max;
 149         timeu64_t alarm_offset_max;
 150         time64_t start_secs;
 151         time64_t offset_secs;
 152         bool set_start_time;
 153
 154 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 155         struct work_struct uie_task;
 156         struct timer_list uie_timer;
 157         /* Those fields are protected by rtc->irq_lock */
 158         unsigned int oldsecs;
 159         unsigned int uie_irq_active:1;
 160         unsigned int stop_uie_polling:1;
 161         unsigned int uie_task_active:1;
 162         unsigned int uie_timer_active:1;
 163 #endif
 164 };
 165 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
 166
 167 #define rtc_lock(d) mutex_lock(&d->ops_lock)
 168 #define rtc_unlock(d) mutex_unlock(&d->ops_lock)
 169
 170 /* useful timestamps */
 171 #define RTC_TIMESTAMP_BEGIN_0000        -62167219200ULL /* 0000-01-01 00:00:00 */
 172 #define RTC_TIMESTAMP_BEGIN_1900        -2208988800LL /* 1900-01-01 00:00:00 */
 173 #define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
 174 #define RTC_TIMESTAMP_END_2063          2966371199LL /* 2063-12-31 23:59:59 */
 175 #define RTC_TIMESTAMP_END_2079          3471292799LL /* 2079-12-31 23:59:59 */
 176 #define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
 177 #define RTC_TIMESTAMP_END_2199          7258118399LL /* 2199-12-31 23:59:59 */
 178 #define RTC_TIMESTAMP_END_9999          253402300799LL /* 9999-12-31 23:59:59 */
 179
 180 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
 181                                         const char *name,
 182                                         const struct rtc_class_ops *ops,
 183                                         struct module *owner);
 184 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
 185 int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
 186
 187 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
 188 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
 189 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
 190 extern int rtc_read_alarm(struct rtc_device *rtc,
 191                         struct rtc_wkalrm *alrm);
 192 extern int rtc_set_alarm(struct rtc_device *rtc,
 193                                 struct rtc_wkalrm *alrm);
 194 extern int rtc_initialize_alarm(struct rtc_device *rtc,
 195                                 struct rtc_wkalrm *alrm);
 196 extern void rtc_update_irq(struct rtc_device *rtc,
 197                         unsigned long num, unsigned long events);
 198
 199 extern struct rtc_device *rtc_class_open(const char *name);
 200 extern void rtc_class_close(struct rtc_device *rtc);
 201
 202 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
 203 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
 204 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 205 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 206 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
 207                                                 unsigned int enabled);
 208
 209 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
 210 void rtc_aie_update_irq(struct rtc_device *rtc);
 211 void rtc_uie_update_irq(struct rtc_device *rtc);
 212 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
 213
 214 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
 215                     struct rtc_device *rtc);
 216 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
 217                     ktime_t expires, ktime_t period);
 218 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
 219 int rtc_read_offset(struct rtc_device *rtc, long *offset);
 220 int rtc_set_offset(struct rtc_device *rtc, long offset);
 221 void rtc_timer_do_work(struct work_struct *work);
 222
 223 static inline bool is_leap_year(unsigned int year)
 224 {
 225         return (!(year % 4) && (year % 100)) || !(year % 400);
 226 }
 227
 228 /**
 229  * rtc_bound_alarmtime() - Return alarm time bound by rtc limit
 230  * @rtc: Pointer to rtc device structure
 231  * @requested: Requested alarm timeout
 232  *
 233  * Return: Alarm timeout bound by maximum alarm time supported by rtc.
 234  */
 235 static inline ktime_t rtc_bound_alarmtime(struct rtc_device *rtc,
 236                                           ktime_t requested)
 237 {
 238         if (rtc->alarm_offset_max &&
 239             rtc->alarm_offset_max * MSEC_PER_SEC < ktime_to_ms(requested))
 240                 return ms_to_ktime(rtc->alarm_offset_max * MSEC_PER_SEC);
 241
 242         return requested;
 243 }
 244
 245 #define devm_rtc_register_device(device) \
 246         __devm_rtc_register_device(THIS_MODULE, device)
 247
 248 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
 249 extern int rtc_hctosys_ret;
 250 #else
 251 #define rtc_hctosys_ret -ENODEV
 252 #endif
 253
 254 #ifdef CONFIG_RTC_NVMEM
 255 int devm_rtc_nvmem_register(struct rtc_device *rtc,
 256                             struct nvmem_config *nvmem_config);
 257 #else
 258 static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
 259                                           struct nvmem_config *nvmem_config)
 260 {
 261         return 0;
 262 }
 263 #endif
 264
 265 #ifdef CONFIG_RTC_INTF_SYSFS
 266 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
 267 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
 268 #else
 269 static inline
 270 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
 271 {
 272         return 0;
 273 }
 274
 275 static inline
 276 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
 277 {
 278         return 0;
 279 }
 280 #endif
 281 #endif /* _LINUX_RTC_H_ */