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 static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
  38 {
  39         rtc_time64_to_tm(time, tm);
  40 }
  41
  42 static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
  43 {
  44         *time = rtc_tm_to_time64(tm);
  45
  46         return 0;
  47 }
  48
  49 #include <linux/device.h>
  50 #include <linux/seq_file.h>
  51 #include <linux/cdev.h>
  52 #include <linux/poll.h>
  53 #include <linux/mutex.h>
  54 #include <linux/timerqueue.h>
  55 #include <linux/workqueue.h>
  56
  57 extern struct class *rtc_class;
  58
  59 /*
  60  * For these RTC methods the device parameter is the physical device
  61  * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
  62  * was passed to rtc_device_register().  Its driver_data normally holds
  63  * device state, including the rtc_device pointer for the RTC.
  64  *
  65  * Most of these methods are called with rtc_device.ops_lock held,
  66  * through the rtc_*(struct rtc_device *, ...) calls.
  67  *
  68  * The (current) exceptions are mostly filesystem hooks:
  69  *   - the proc() hook for procfs
  70  *   - non-ioctl() chardev hooks:  open(), release()
  71  *
  72  * REVISIT those periodic irq calls *do* have ops_lock when they're
  73  * issued through ioctl() ...
  74  */
  75 struct rtc_class_ops {
  76         int (*ioctl)(struct device *, unsigned int, unsigned long);
  77         int (*read_time)(struct device *, struct rtc_time *);
  78         int (*set_time)(struct device *, struct rtc_time *);
  79         int (*read_alarm)(struct device *, struct rtc_wkalrm *);
  80         int (*set_alarm)(struct device *, struct rtc_wkalrm *);
  81         int (*proc)(struct device *, struct seq_file *);
  82         int (*alarm_irq_enable)(struct device *, unsigned int enabled);
  83         int (*read_offset)(struct device *, long *offset);
  84         int (*set_offset)(struct device *, long offset);
  85 };
  86
  87 struct rtc_device;
  88
  89 struct rtc_timer {
  90         struct timerqueue_node node;
  91         ktime_t period;
  92         void (*func)(struct rtc_device *rtc);
  93         struct rtc_device *rtc;
  94         int enabled;
  95 };
  96
  97 /* flags */
  98 #define RTC_DEV_BUSY 0
  99
 100 struct rtc_device {
 101         struct device dev;
 102         struct module *owner;
 103
 104         int id;
 105
 106         const struct rtc_class_ops *ops;
 107         struct mutex ops_lock;
 108
 109         struct cdev char_dev;
 110         unsigned long flags;
 111
 112         unsigned long irq_data;
 113         spinlock_t irq_lock;
 114         wait_queue_head_t irq_queue;
 115         struct fasync_struct *async_queue;
 116
 117         int irq_freq;
 118         int max_user_freq;
 119
 120         struct timerqueue_head timerqueue;
 121         struct rtc_timer aie_timer;
 122         struct rtc_timer uie_rtctimer;
 123         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
 124         int pie_enabled;
 125         struct work_struct irqwork;
 126         /* Some hardware can't support UIE mode */
 127         int uie_unsupported;
 128
 129         /* Number of nsec it takes to set the RTC clock. This influences when
 130          * the set ops are called. An offset:
 131          *   - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
 132          *   - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
 133          *   - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
 134          */
 135         long set_offset_nsec;
 136
 137         bool registered;
 138
 139         /* Old ABI support */
 140         bool nvram_old_abi;
 141         struct bin_attribute *nvram;
 142
 143         time64_t range_min;
 144         timeu64_t range_max;
 145         time64_t start_secs;
 146         time64_t offset_secs;
 147         bool set_start_time;
 148
 149 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 150         struct work_struct uie_task;
 151         struct timer_list uie_timer;
 152         /* Those fields are protected by rtc->irq_lock */
 153         unsigned int oldsecs;
 154         unsigned int uie_irq_active:1;
 155         unsigned int stop_uie_polling:1;
 156         unsigned int uie_task_active:1;
 157         unsigned int uie_timer_active:1;
 158 #endif
 159 };
 160 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
 161
 162 /* useful timestamps */
 163 #define RTC_TIMESTAMP_BEGIN_1900        -2208988800LL /* 1900-01-01 00:00:00 */
 164 #define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
 165 #define RTC_TIMESTAMP_END_2063          2966371199LL /* 2063-12-31 23:59:59 */
 166 #define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
 167 #define RTC_TIMESTAMP_END_9999          253402300799LL /* 9999-12-31 23:59:59 */
 168
 169 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
 170                                         const char *name,
 171                                         const struct rtc_class_ops *ops,
 172                                         struct module *owner);
 173 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
 174 int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
 175
 176 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
 177 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
 178 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
 179 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
 180 extern int rtc_read_alarm(struct rtc_device *rtc,
 181                         struct rtc_wkalrm *alrm);
 182 extern int rtc_set_alarm(struct rtc_device *rtc,
 183                                 struct rtc_wkalrm *alrm);
 184 extern int rtc_initialize_alarm(struct rtc_device *rtc,
 185                                 struct rtc_wkalrm *alrm);
 186 extern void rtc_update_irq(struct rtc_device *rtc,
 187                         unsigned long num, unsigned long events);
 188
 189 extern struct rtc_device *rtc_class_open(const char *name);
 190 extern void rtc_class_close(struct rtc_device *rtc);
 191
 192 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
 193 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
 194 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 195 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 196 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
 197                                                 unsigned int enabled);
 198
 199 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
 200 void rtc_aie_update_irq(struct rtc_device *rtc);
 201 void rtc_uie_update_irq(struct rtc_device *rtc);
 202 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
 203
 204 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
 205                     struct rtc_device *rtc);
 206 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
 207                     ktime_t expires, ktime_t period);
 208 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
 209 int rtc_read_offset(struct rtc_device *rtc, long *offset);
 210 int rtc_set_offset(struct rtc_device *rtc, long offset);
 211 void rtc_timer_do_work(struct work_struct *work);
 212
 213 static inline bool is_leap_year(unsigned int year)
 214 {
 215         return (!(year % 4) && (year % 100)) || !(year % 400);
 216 }
 217
 218 /* Determine if we can call to driver to set the time. Drivers can only be
 219  * called to set a second aligned time value, and the field set_offset_nsec
 220  * specifies how far away from the second aligned time to call the driver.
 221  *
 222  * This also computes 'to_set' which is the time we are trying to set, and has
 223  * a zero in tv_nsecs, such that:
 224  *    to_set - set_delay_nsec == now +/- FUZZ
 225  *
 226  */
 227 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
 228                                   struct timespec64 *to_set,
 229                                   const struct timespec64 *now)
 230 {
 231         /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
 232         const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
 233         struct timespec64 delay = {.tv_sec = 0,
 234                                    .tv_nsec = set_offset_nsec};
 235
 236         *to_set = timespec64_add(*now, delay);
 237
 238         if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
 239                 to_set->tv_nsec = 0;
 240                 return true;
 241         }
 242
 243         if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
 244                 to_set->tv_sec++;
 245                 to_set->tv_nsec = 0;
 246                 return true;
 247         }
 248         return false;
 249 }
 250
 251 #define rtc_register_device(device) \
 252         __rtc_register_device(THIS_MODULE, device)
 253
 254 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
 255 extern int rtc_hctosys_ret;
 256 #else
 257 #define rtc_hctosys_ret -ENODEV
 258 #endif
 259
 260 #ifdef CONFIG_RTC_NVMEM
 261 int rtc_nvmem_register(struct rtc_device *rtc,
 262                        struct nvmem_config *nvmem_config);
 263 void rtc_nvmem_unregister(struct rtc_device *rtc);
 264 #else
 265 static inline int rtc_nvmem_register(struct rtc_device *rtc,
 266                                      struct nvmem_config *nvmem_config)
 267 {
 268         return 0;
 269 }
 270 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
 271 #endif
 272
 273 #ifdef CONFIG_RTC_INTF_SYSFS
 274 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
 275 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
 276 #else
 277 static inline
 278 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
 279 {
 280         return 0;
 281 }
 282
 283 static inline
 284 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
 285 {
 286         return 0;
 287 }
 288 #endif
 289 #endif /* _LINUX_RTC_H_ */