LXR linux/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
  21extern int rtc_month_days(unsigned int month, unsigned int year);
  22extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
  23extern int rtc_valid_tm(struct rtc_time *tm);
  24extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
  25extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
  26ktime_t rtc_tm_to_ktime(struct rtc_time tm);
  27struct rtc_time rtc_ktime_to_tm(ktime_t kt);
  28
  29/*
  30 * rtc_tm_sub - Return the difference in seconds.
  31 */
  32static 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
  37static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
  38{
  39        rtc_time64_to_tm(time, tm);
  40}
  41
  42static 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
  57extern 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(), read_callback()
  71 *
  72 * REVISIT those periodic irq calls *do* have ops_lock when they're
  73 * issued through ioctl() ...
  74 */
  75struct 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 (*set_mmss64)(struct device *, time64_t secs);
  83        int (*set_mmss)(struct device *, unsigned long secs);
  84        int (*read_callback)(struct device *, int data);
  85        int (*alarm_irq_enable)(struct device *, unsigned int enabled);
  86        int (*read_offset)(struct device *, long *offset);
  87        int (*set_offset)(struct device *, long offset);
  88};
  89
  90struct rtc_timer {
  91        struct timerqueue_node node;
  92        ktime_t period;
  93        void (*func)(void *private_data);
  94        void *private_data;
  95        int enabled;
  96};
  97
  98
  99/* flags */
 100#define RTC_DEV_BUSY 0
 101
 102struct rtc_device {
 103        struct device dev;
 104        struct module *owner;
 105
 106        int id;
 107
 108        const struct rtc_class_ops *ops;
 109        struct mutex ops_lock;
 110
 111        struct cdev char_dev;
 112        unsigned long flags;
 113
 114        unsigned long irq_data;
 115        spinlock_t irq_lock;
 116        wait_queue_head_t irq_queue;
 117        struct fasync_struct *async_queue;
 118
 119        int irq_freq;
 120        int max_user_freq;
 121
 122        struct timerqueue_head timerqueue;
 123        struct rtc_timer aie_timer;
 124        struct rtc_timer uie_rtctimer;
 125        struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
 126        int pie_enabled;
 127        struct work_struct irqwork;
 128        /* Some hardware can't support UIE mode */
 129        int uie_unsupported;
 130
 131        /* Number of nsec it takes to set the RTC clock. This influences when
 132         * the set ops are called. An offset:
 133         *   - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
 134         *   - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
 135         *   - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
 136         */
 137        long set_offset_nsec;
 138
 139        bool registered;
 140
 141        struct nvmem_device *nvmem;
 142        /* Old ABI support */
 143        bool nvram_old_abi;
 144        struct bin_attribute *nvram;
 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/* useful timestamps */
 166#define RTC_TIMESTAMP_BEGIN_1900        -2208989361LL /* 1900-01-01 00:00:00 */
 167#define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
 168#define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
 169
 170extern struct rtc_device *rtc_device_register(const char *name,
 171                                        struct device *dev,
 172                                        const struct rtc_class_ops *ops,
 173                                        struct module *owner);
 174extern struct rtc_device *devm_rtc_device_register(struct device *dev,
 175                                        const char *name,
 176                                        const struct rtc_class_ops *ops,
 177                                        struct module *owner);
 178struct rtc_device *devm_rtc_allocate_device(struct device *dev);
 179int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
 180extern void rtc_device_unregister(struct rtc_device *rtc);
 181extern void devm_rtc_device_unregister(struct device *dev,
 182                                        struct rtc_device *rtc);
 183
 184extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
 185extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
 186extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
 187int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
 188extern int rtc_read_alarm(struct rtc_device *rtc,
 189                        struct rtc_wkalrm *alrm);
 190extern int rtc_set_alarm(struct rtc_device *rtc,
 191                                struct rtc_wkalrm *alrm);
 192extern int rtc_initialize_alarm(struct rtc_device *rtc,
 193                                struct rtc_wkalrm *alrm);
 194extern void rtc_update_irq(struct rtc_device *rtc,
 195                        unsigned long num, unsigned long events);
 196
 197extern struct rtc_device *rtc_class_open(const char *name);
 198extern void rtc_class_close(struct rtc_device *rtc);
 199
 200extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
 201extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
 202extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 203extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
 204extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
 205                                                unsigned int enabled);
 206
 207void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
 208void rtc_aie_update_irq(void *private);
 209void rtc_uie_update_irq(void *private);
 210enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
 211
 212void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
 213int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
 214                    ktime_t expires, ktime_t period);
 215void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
 216int rtc_read_offset(struct rtc_device *rtc, long *offset);
 217int rtc_set_offset(struct rtc_device *rtc, long offset);
 218void rtc_timer_do_work(struct work_struct *work);
 219
 220static inline bool is_leap_year(unsigned int year)
 221{
 222        return (!(year % 4) && (year % 100)) || !(year % 400);
 223}
 224
 225/* Determine if we can call to driver to set the time. Drivers can only be
 226 * called to set a second aligned time value, and the field set_offset_nsec
 227 * specifies how far away from the second aligned time to call the driver.
 228 *
 229 * This also computes 'to_set' which is the time we are trying to set, and has
 230 * a zero in tv_nsecs, such that:
 231 *    to_set - set_delay_nsec == now +/- FUZZ
 232 *
 233 */
 234static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
 235                                  struct timespec64 *to_set,
 236                                  const struct timespec64 *now)
 237{
 238        /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
 239        const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
 240        struct timespec64 delay = {.tv_sec = 0,
 241                                   .tv_nsec = set_offset_nsec};
 242
 243        *to_set = timespec64_add(*now, delay);
 244
 245        if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
 246                to_set->tv_nsec = 0;
 247                return true;
 248        }
 249
 250        if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
 251                to_set->tv_sec++;
 252                to_set->tv_nsec = 0;
 253                return true;
 254        }
 255        return false;
 256}
 257
 258#define rtc_register_device(device) \
 259        __rtc_register_device(THIS_MODULE, device)
 260
 261#ifdef CONFIG_RTC_HCTOSYS_DEVICE
 262extern int rtc_hctosys_ret;
 263#else
 264#define rtc_hctosys_ret -ENODEV
 265#endif
 266
 267#ifdef CONFIG_RTC_NVMEM
 268int rtc_nvmem_register(struct rtc_device *rtc,
 269                       struct nvmem_config *nvmem_config);
 270void rtc_nvmem_unregister(struct rtc_device *rtc);
 271#else
 272static inline int rtc_nvmem_register(struct rtc_device *rtc,
 273                                     struct nvmem_config *nvmem_config)
 274{
 275        return 0;
 276}
 277static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
 278#endif
 279
 280#endif /* _LINUX_RTC_H_ */
 281