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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 /* Number of nsec it takes to set the RTC clock. This influences when
114 * the set ops are called. An offset:
115 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
116 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
117 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
118 */
119 long set_offset_nsec;
120
121 bool registered;
122
123 /* Old ABI support */
124 bool nvram_old_abi;
125 struct bin_attribute *nvram;
126
127 time64_t range_min;
128 timeu64_t range_max;
129 time64_t start_secs;
130 time64_t offset_secs;
131 bool set_start_time;
132
133#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
134 struct work_struct uie_task;
135 struct timer_list uie_timer;
136 /* Those fields are protected by rtc->irq_lock */
137 unsigned int oldsecs;
138 unsigned int uie_irq_active:1;
139 unsigned int stop_uie_polling:1;
140 unsigned int uie_task_active:1;
141 unsigned int uie_timer_active:1;
142#endif
143};
144#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
145
146#define rtc_lock(d) mutex_lock(&d->ops_lock)
147#define rtc_unlock(d) mutex_unlock(&d->ops_lock)
148
149/* useful timestamps */
150#define RTC_TIMESTAMP_BEGIN_0000 -62167219200ULL /* 0000-01-01 00:00:00 */
151#define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */
152#define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
153#define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
154#define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */
155#define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
156#define RTC_TIMESTAMP_END_2199 7258118399LL /* 2199-12-31 23:59:59 */
157#define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
158
159extern struct rtc_device *devm_rtc_device_register(struct device *dev,
160 const char *name,
161 const struct rtc_class_ops *ops,
162 struct module *owner);
163struct rtc_device *devm_rtc_allocate_device(struct device *dev);
164int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
165
166extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
167extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
168extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
169int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
170extern int rtc_read_alarm(struct rtc_device *rtc,
171 struct rtc_wkalrm *alrm);
172extern int rtc_set_alarm(struct rtc_device *rtc,
173 struct rtc_wkalrm *alrm);
174extern int rtc_initialize_alarm(struct rtc_device *rtc,
175 struct rtc_wkalrm *alrm);
176extern void rtc_update_irq(struct rtc_device *rtc,
177 unsigned long num, unsigned long events);
178
179extern struct rtc_device *rtc_class_open(const char *name);
180extern void rtc_class_close(struct rtc_device *rtc);
181
182extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
183extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
184extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
185extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
186extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
187 unsigned int enabled);
188
189void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
190void rtc_aie_update_irq(struct rtc_device *rtc);
191void rtc_uie_update_irq(struct rtc_device *rtc);
192enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
193
194void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
195 struct rtc_device *rtc);
196int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
197 ktime_t expires, ktime_t period);
198void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
199int rtc_read_offset(struct rtc_device *rtc, long *offset);
200int rtc_set_offset(struct rtc_device *rtc, long offset);
201void rtc_timer_do_work(struct work_struct *work);
202
203static inline bool is_leap_year(unsigned int year)
204{
205 return (!(year % 4) && (year % 100)) || !(year % 400);
206}
207
208/* Determine if we can call to driver to set the time. Drivers can only be
209 * called to set a second aligned time value, and the field set_offset_nsec
210 * specifies how far away from the second aligned time to call the driver.
211 *
212 * This also computes 'to_set' which is the time we are trying to set, and has
213 * a zero in tv_nsecs, such that:
214 * to_set - set_delay_nsec == now +/- FUZZ
215 *
216 */
217static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
218 struct timespec64 *to_set,
219 const struct timespec64 *now)
220{
221 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
222 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
223 struct timespec64 delay = {.tv_sec = 0,
224 .tv_nsec = set_offset_nsec};
225
226 *to_set = timespec64_add(*now, delay);
227
228 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
229 to_set->tv_nsec = 0;
230 return true;
231 }
232
233 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
234 to_set->tv_sec++;
235 to_set->tv_nsec = 0;
236 return true;
237 }
238 return false;
239}
240
241#define rtc_register_device(device) \
242 __rtc_register_device(THIS_MODULE, device)
243
244#ifdef CONFIG_RTC_HCTOSYS_DEVICE
245extern int rtc_hctosys_ret;
246#else
247#define rtc_hctosys_ret -ENODEV
248#endif
249
250#ifdef CONFIG_RTC_NVMEM
251int rtc_nvmem_register(struct rtc_device *rtc,
252 struct nvmem_config *nvmem_config);
253void rtc_nvmem_unregister(struct rtc_device *rtc);
254#else
255static inline int rtc_nvmem_register(struct rtc_device *rtc,
256 struct nvmem_config *nvmem_config)
257{
258 return 0;
259}
260static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
261#endif
262
263#ifdef CONFIG_RTC_INTF_SYSFS
264int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
265int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
266#else
267static inline
268int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
269{
270 return 0;
271}
272
273static inline
274int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
275{
276 return 0;
277}
278#endif
279#endif /* _LINUX_RTC_H_ */