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(tm: lhs) - rtc_tm_to_time64(tm: 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 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 */
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 int (*param_get)(struct device *, struct rtc_param *param);
70 int (*param_set)(struct device *, struct rtc_param *param);
71};
72
73struct rtc_device;
74
75struct 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
87struct 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_EPOCH_GPS 315964800LL /* 1980-01-06 00:00:00 */
174#define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
175#define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
176#define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */
177#define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
178#define RTC_TIMESTAMP_END_2199 7258118399LL /* 2199-12-31 23:59:59 */
179#define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
180
181extern struct rtc_device *devm_rtc_device_register(struct device *dev,
182 const char *name,
183 const struct rtc_class_ops *ops,
184 struct module *owner);
185struct rtc_device *devm_rtc_allocate_device(struct device *dev);
186int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
187
188extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
189extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
190int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
191extern int rtc_read_alarm(struct rtc_device *rtc,
192 struct rtc_wkalrm *alrm);
193extern int rtc_set_alarm(struct rtc_device *rtc,
194 struct rtc_wkalrm *alrm);
195extern int rtc_initialize_alarm(struct rtc_device *rtc,
196 struct rtc_wkalrm *alrm);
197extern void rtc_update_irq(struct rtc_device *rtc,
198 unsigned long num, unsigned long events);
199
200extern struct rtc_device *rtc_class_open(const char *name);
201extern void rtc_class_close(struct rtc_device *rtc);
202
203extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
204extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
205extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
206extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
207extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
208 unsigned int enabled);
209
210void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
211void rtc_aie_update_irq(struct rtc_device *rtc);
212void rtc_uie_update_irq(struct rtc_device *rtc);
213enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
214
215void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
216 struct rtc_device *rtc);
217int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
218 ktime_t expires, ktime_t period);
219void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
220int rtc_read_offset(struct rtc_device *rtc, long *offset);
221int rtc_set_offset(struct rtc_device *rtc, long offset);
222void rtc_timer_do_work(struct work_struct *work);
223
224static inline bool is_leap_year(unsigned int year)
225{
226 return (!(year % 4) && (year % 100)) || !(year % 400);
227}
228
229/**
230 * rtc_bound_alarmtime() - Return alarm time bound by rtc limit
231 * @rtc: Pointer to rtc device structure
232 * @requested: Requested alarm timeout
233 *
234 * Return: Alarm timeout bound by maximum alarm time supported by rtc.
235 */
236static inline ktime_t rtc_bound_alarmtime(struct rtc_device *rtc,
237 ktime_t requested)
238{
239 if (rtc->alarm_offset_max &&
240 rtc->alarm_offset_max * MSEC_PER_SEC < ktime_to_ms(kt: requested))
241 return ms_to_ktime(ms: rtc->alarm_offset_max * MSEC_PER_SEC);
242
243 return requested;
244}
245
246#define devm_rtc_register_device(device) \
247 __devm_rtc_register_device(THIS_MODULE, device)
248
249#ifdef CONFIG_RTC_HCTOSYS_DEVICE
250extern int rtc_hctosys_ret;
251#else
252#define rtc_hctosys_ret -ENODEV
253#endif
254
255#ifdef CONFIG_RTC_NVMEM
256int devm_rtc_nvmem_register(struct rtc_device *rtc,
257 struct nvmem_config *nvmem_config);
258#else
259static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
260 struct nvmem_config *nvmem_config)
261{
262 return 0;
263}
264#endif
265
266#ifdef CONFIG_RTC_INTF_SYSFS
267int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
268int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
269#else
270static inline
271int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
272{
273 return 0;
274}
275
276static inline
277int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
278{
279 return 0;
280}
281#endif
282#endif /* _LINUX_RTC_H_ */
283