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
  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
  45extern 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 */
  59struct 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
  71struct rtc_device;
  72
  73struct 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
  84struct 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
 178extern 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);
 182struct rtc_device *devm_rtc_allocate_device(struct device *dev);
 183int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
 184
 185extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
 186extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
 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(struct rtc_device *rtc);
 209void rtc_uie_update_irq(struct rtc_device *rtc);
 210enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
 211
 212void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
 213                    struct rtc_device *rtc);
 214int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
 215                    ktime_t expires, ktime_t period);
 216void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
 217int rtc_read_offset(struct rtc_device *rtc, long *offset);
 218int rtc_set_offset(struct rtc_device *rtc, long offset);
 219void rtc_timer_do_work(struct work_struct *work);
 220
 221static 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
 230extern int rtc_hctosys_ret;
 231#else
 232#define rtc_hctosys_ret -ENODEV
 233#endif
 234
 235#ifdef CONFIG_RTC_NVMEM
 236int devm_rtc_nvmem_register(struct rtc_device *rtc,
 237                            struct nvmem_config *nvmem_config);
 238#else
 239static 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
 247int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
 248int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
 249#else
 250static inline
 251int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
 252{
 253        return 0;
 254}
 255
 256static inline
 257int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
 258{
 259        return 0;
 260}
 261#endif
 262#endif /* _LINUX_RTC_H_ */
 263