xref: /linux/include/linux/rtc.h (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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  */
rtc_tm_sub(struct rtc_time * lhs,struct rtc_time * rhs)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 
is_leap_year(unsigned int year)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  */
rtc_bound_alarmtime(struct rtc_device * rtc,ktime_t requested)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
devm_rtc_nvmem_register(struct rtc_device * rtc,struct nvmem_config * nvmem_config)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
rtc_add_group(struct rtc_device * rtc,const struct attribute_group * grp)270 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
271 {
272 	return 0;
273 }
274 
275 static inline
rtc_add_groups(struct rtc_device * rtc,const struct attribute_group ** grps)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