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 #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
45 extern 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 */
59 struct 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
73 struct rtc_device;
74
75 struct 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
87 struct 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_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
174 #define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
175 #define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */
176 #define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
177 #define RTC_TIMESTAMP_END_2199 7258118399LL /* 2199-12-31 23:59:59 */
178 #define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
179
180 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
181 const char *name,
182 const struct rtc_class_ops *ops,
183 struct module *owner);
184 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
185 int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
186
187 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
188 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
189 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
190 extern int rtc_read_alarm(struct rtc_device *rtc,
191 struct rtc_wkalrm *alrm);
192 extern int rtc_set_alarm(struct rtc_device *rtc,
193 struct rtc_wkalrm *alrm);
194 extern int rtc_initialize_alarm(struct rtc_device *rtc,
195 struct rtc_wkalrm *alrm);
196 extern void rtc_update_irq(struct rtc_device *rtc,
197 unsigned long num, unsigned long events);
198
199 extern struct rtc_device *rtc_class_open(const char *name);
200 extern void rtc_class_close(struct rtc_device *rtc);
201
202 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
203 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
204 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
205 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
206 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
207 unsigned int enabled);
208
209 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
210 void rtc_aie_update_irq(struct rtc_device *rtc);
211 void rtc_uie_update_irq(struct rtc_device *rtc);
212 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
213
214 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
215 struct rtc_device *rtc);
216 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
217 ktime_t expires, ktime_t period);
218 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
219 int rtc_read_offset(struct rtc_device *rtc, long *offset);
220 int rtc_set_offset(struct rtc_device *rtc, long offset);
221 void rtc_timer_do_work(struct work_struct *work);
222
223 static inline bool is_leap_year(unsigned int year)
224 {
225 return (!(year % 4) && (year % 100)) || !(year % 400);
226 }
227
228 /**
229 * rtc_bound_alarmtime() - Return alarm time bound by rtc limit
230 * @rtc: Pointer to rtc device structure
231 * @requested: Requested alarm timeout
232 *
233 * Return: Alarm timeout bound by maximum alarm time supported by rtc.
234 */
235 static inline ktime_t rtc_bound_alarmtime(struct rtc_device *rtc,
236 ktime_t requested)
237 {
238 if (rtc->alarm_offset_max &&
239 rtc->alarm_offset_max * MSEC_PER_SEC < ktime_to_ms(requested))
240 return ms_to_ktime(rtc->alarm_offset_max * MSEC_PER_SEC);
241
242 return requested;
243 }
244
245 #define devm_rtc_register_device(device) \
246 __devm_rtc_register_device(THIS_MODULE, device)
247
248 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
249 extern int rtc_hctosys_ret;
250 #else
251 #define rtc_hctosys_ret -ENODEV
252 #endif
253
254 #ifdef CONFIG_RTC_NVMEM
255 int devm_rtc_nvmem_register(struct rtc_device *rtc,
256 struct nvmem_config *nvmem_config);
257 #else
258 static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
259 struct nvmem_config *nvmem_config)
260 {
261 return 0;
262 }
263 #endif
264
265 #ifdef CONFIG_RTC_INTF_SYSFS
266 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
267 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
268 #else
269 static inline
270 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
271 {
272 return 0;
273 }
274
275 static inline
276 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
277 {
278 return 0;
279 }
280 #endif
281 #endif /* _LINUX_RTC_H_ */
282
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.