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 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 };
  70
  71 struct rtc_device;
  72
  73 struct rtc_timer {
  74         struct timerqueue_node node;
  75         ktime_t period;
  76         void (*func)(struct rtc_device *rtc);
  77         struct rtc_device *rtc;
  78         int enabled;
  79 };
  80
  81 /* flags */
  82 #define RTC_DEV_BUSY 0
  83
  84 struct rtc_device {
  85         struct device dev;
  86         struct module *owner;
  87
  88         int id;
  89
  90         const struct rtc_class_ops *ops;
  91         struct mutex ops_lock;
  92
  93         struct cdev char_dev;
  94         unsigned long flags;
  95
  96         unsigned long irq_data;
  97         spinlock_t irq_lock;
  98         wait_queue_head_t irq_queue;
  99         struct fasync_struct *async_queue;
 100
 101         int irq_freq;
 102         int max_user_freq;
 103
 104         struct timerqueue_head timerqueue;
 105         struct rtc_timer aie_timer;
 106         struct rtc_timer uie_rtctimer;
 107         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
 108         int pie_enabled;
 109         struct work_struct irqwork;
 110         /* Some hardware can't support UIE mode */
 111         int uie_unsupported;
 112
 113         /*
 114          * This offset specifies the update timing of the RTC.
 115          *
 116          * tsched     t1 write(t2.tv_sec - 1sec))  t2 RTC increments seconds
 117          *
 118          * The offset defines how tsched is computed so that the write to
 119          * the RTC (t2.tv_sec - 1sec) is correct versus the time required
 120          * for the transport of the write and the time which the RTC needs
 121          * to increment seconds the first time after the write (t2).
 122          *
 123          * For direct accessible RTCs tsched ~= t1 because the write time
 124          * is negligible. For RTCs behind slow busses the transport time is
 125          * significant and has to be taken into account.
 126          *
 127          * The time between the write (t1) and the first increment after
 128          * the write (t2) is RTC specific. For a MC146818 RTC it's 500ms,
 129          * for many others it's exactly 1 second. Consult the datasheet.
 130          *
 131          * The value of this offset is also used to calculate the to be
 132          * written value (t2.tv_sec - 1sec) at tsched.
 133          *
 134          * The default value for this is NSEC_PER_SEC + 10 msec default
 135          * transport time. The offset can be adjusted by drivers so the
 136          * calculation for the to be written value at tsched becomes
 137          * correct:
 138          *
 139          *      newval = tsched + set_offset_nsec - NSEC_PER_SEC
 140          * and  (tsched + set_offset_nsec) % NSEC_PER_SEC == 0
 141          */
 142         unsigned long set_offset_nsec;
 143
 144         unsigned long features[BITS_TO_LONGS(RTC_FEATURE_CNT)];
 145
 146         time64_t range_min;
 147         timeu64_t range_max;
 148         time64_t start_secs;
 149         time64_t offset_secs;
 150         bool set_start_time;
 151
 152 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 153         struct work_struct uie_task;
 154         struct timer_list uie_timer;
 155         /* Those fields are protected by rtc->irq_lock */
 156         unsigned int oldsecs;
 157         unsigned int uie_irq_active:1;
 158         unsigned int stop_uie_polling:1;
 159         unsigned int uie_task_active:1;
 160         unsigned int uie_timer_active:1;
 161 #endif
 162 };
 163 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
 164
 165 #define rtc_lock(d) mutex_lock(&d->ops_lock)
 166 #define rtc_unlock(d) mutex_unlock(&d->ops_lock)
 167
 168 /* useful timestamps */
 169 #define RTC_TIMESTAMP_BEGIN_0000        -62167219200ULL /* 0000-01-01 00:00:00 */
 170 #define RTC_TIMESTAMP_BEGIN_1900        -2208988800LL /* 1900-01-01 00:00:00 */
 171 #define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
 172 #define RTC_TIMESTAMP_END_2063          2966371199LL /* 2063-12-31 23:59:59 */
 173 #define RTC_TIMESTAMP_END_2079          3471292799LL /* 2079-12-31 23:59:59 */
 174 #define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
 175 #define RTC_TIMESTAMP_END_2199          7258118399LL /* 2199-12-31 23:59:59 */
 176 #define RTC_TIMESTAMP_END_9999          253402300799LL /* 9999-12-31 23:59:59 */
 177
 178 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
 179                                         const char *name,
 180                                         const struct rtc_class_ops *ops,
 181                                         struct module *owner);
 182 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
 183 int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
 184
 185 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
 186 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
 187 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
 188 extern int rtc_read_alarm(struct rtc_device *rtc,
 189                         struct rtc_wkalrm *alrm);
 190 extern int rtc_set_alarm(struct rtc_device *rtc,
 191                                 struct rtc_wkalrm *alrm);
 192 extern int rtc_initialize_alarm(struct rtc_device *rtc,
 193                                 struct rtc_wkalrm *alrm);
 194 extern void rtc_update_irq(struct rtc_device *rtc,
 195                         unsigned long num, unsigned long events);
 196
 197 extern struct rtc_device *rtc_class_open(const char *name);
 198 extern void rtc_class_close(struct rtc_device *rtc);
 199
 200 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
 201 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
 202 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 203 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 204 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
 205                                                 unsigned int enabled);
 206
 207 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
 208 void rtc_aie_update_irq(struct rtc_device *rtc);
 209 void rtc_uie_update_irq(struct rtc_device *rtc);
 210 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
 211
 212 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
 213                     struct rtc_device *rtc);
 214 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
 215                     ktime_t expires, ktime_t period);
 216 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
 217 int rtc_read_offset(struct rtc_device *rtc, long *offset);
 218 int rtc_set_offset(struct rtc_device *rtc, long offset);
 219 void rtc_timer_do_work(struct work_struct *work);
 220
 221 static inline bool is_leap_year(unsigned int year)
 222 {
 223         return (!(year % 4) && (year % 100)) || !(year % 400);
 224 }
 225
 226 #define devm_rtc_register_device(device) \
 227         __devm_rtc_register_device(THIS_MODULE, device)
 228
 229 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
 230 extern int rtc_hctosys_ret;
 231 #else
 232 #define rtc_hctosys_ret -ENODEV
 233 #endif
 234
 235 #ifdef CONFIG_RTC_NVMEM
 236 int devm_rtc_nvmem_register(struct rtc_device *rtc,
 237                             struct nvmem_config *nvmem_config);
 238 #else
 239 static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
 240                                           struct nvmem_config *nvmem_config)
 241 {
 242         return 0;
 243 }
 244 #endif
 245
 246 #ifdef CONFIG_RTC_INTF_SYSFS
 247 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
 248 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
 249 #else
 250 static inline
 251 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
 252 {
 253         return 0;
 254 }
 255
 256 static inline
 257 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
 258 {
 259         return 0;
 260 }
 261 #endif
 262 #endif /* _LINUX_RTC_H_ */