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_
16 #include <linux/types.h>
17 #include <linux/interrupt.h>
18 #include <linux/nvmem-provider.h>
19 #include <uapi/linux/rtc.h>
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);
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 }
37 static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
38 {
39 rtc_time64_to_tm(time, tm);
40 }
42 static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
43 {
44 *time = rtc_tm_to_time64(tm);
46 return 0;
47 }
49 #include <linux/device.h>
50 #include <linux/seq_file.h>
51 #include <linux/cdev.h>
52 #include <linux/poll.h>
53 #include <linux/mutex.h>
54 #include <linux/timerqueue.h>
55 #include <linux/workqueue.h>
57 extern struct class *rtc_class;
59 /*
60 * For these RTC methods the device parameter is the physical device
61 * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
62 * was passed to rtc_device_register(). Its driver_data normally holds
63 * device state, including the rtc_device pointer for the RTC.
64 *
65 * Most of these methods are called with rtc_device.ops_lock held,
66 * through the rtc_*(struct rtc_device *, ...) calls.
67 *
68 * The (current) exceptions are mostly filesystem hooks:
69 * - the proc() hook for procfs
70 * - non-ioctl() chardev hooks: open(), release(), read_callback()
71 *
72 * REVISIT those periodic irq calls *do* have ops_lock when they're
73 * issued through ioctl() ...
74 */
75 struct rtc_class_ops {
76 int (*ioctl)(struct device *, unsigned int, unsigned long);
77 int (*read_time)(struct device *, struct rtc_time *);
78 int (*set_time)(struct device *, struct rtc_time *);
79 int (*read_alarm)(struct device *, struct rtc_wkalrm *);
80 int (*set_alarm)(struct device *, struct rtc_wkalrm *);
81 int (*proc)(struct device *, struct seq_file *);
82 int (*set_mmss64)(struct device *, time64_t secs);
83 int (*set_mmss)(struct device *, unsigned long secs);
84 int (*read_callback)(struct device *, int data);
85 int (*alarm_irq_enable)(struct device *, unsigned int enabled);
86 int (*read_offset)(struct device *, long *offset);
87 int (*set_offset)(struct device *, long offset);
88 int (*power_off_program)(struct device *dev);
89 };
91 struct rtc_timer {
92 struct timerqueue_node node;
93 ktime_t period;
94 void (*func)(void *private_data);
95 void *private_data;
96 int enabled;
97 };
100 /* flags */
101 #define RTC_DEV_BUSY 0
103 struct rtc_device {
104 struct device dev;
105 struct module *owner;
107 int id;
109 const struct rtc_class_ops *ops;
110 struct mutex ops_lock;
112 struct cdev char_dev;
113 unsigned long flags;
115 unsigned long irq_data;
116 spinlock_t irq_lock;
117 wait_queue_head_t irq_queue;
118 struct fasync_struct *async_queue;
120 int irq_freq;
121 int max_user_freq;
123 struct timerqueue_head timerqueue;
124 struct rtc_timer aie_timer;
125 struct rtc_timer uie_rtctimer;
126 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
127 int pie_enabled;
128 struct work_struct irqwork;
129 /* Some hardware can't support UIE mode */
130 int uie_unsupported;
132 /* Number of nsec it takes to set the RTC clock. This influences when
133 * the set ops are called. An offset:
134 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
135 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
136 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
137 */
138 long set_offset_nsec;
140 bool registered;
142 struct nvmem_device *nvmem;
143 /* Old ABI support */
144 bool nvram_old_abi;
145 struct bin_attribute *nvram;
147 time64_t range_min;
148 timeu64_t range_max;
149 time64_t start_secs;
150 time64_t offset_secs;
151 bool set_start_time;
153 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
154 struct work_struct uie_task;
155 struct timer_list uie_timer;
156 /* Those fields are protected by rtc->irq_lock */
157 unsigned int oldsecs;
158 unsigned int uie_irq_active:1;
159 unsigned int stop_uie_polling:1;
160 unsigned int uie_task_active:1;
161 unsigned int uie_timer_active:1;
162 #endif
163 };
164 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
166 /* useful timestamps */
167 #define RTC_TIMESTAMP_BEGIN_1900 -2208989361LL /* 1900-01-01 00:00:00 */
168 #define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
169 #define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
171 extern struct rtc_device *rtc_device_register(const char *name,
172 struct device *dev,
173 const struct rtc_class_ops *ops,
174 struct module *owner);
175 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
176 const char *name,
177 const struct rtc_class_ops *ops,
178 struct module *owner);
179 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
180 int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
181 extern void rtc_device_unregister(struct rtc_device *rtc);
182 extern void devm_rtc_device_unregister(struct device *dev,
183 struct rtc_device *rtc);
185 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
186 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
187 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
188 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
189 extern int rtc_read_alarm(struct rtc_device *rtc,
190 struct rtc_wkalrm *alrm);
191 extern int rtc_set_alarm(struct rtc_device *rtc,
192 struct rtc_wkalrm *alrm);
193 extern int rtc_initialize_alarm(struct rtc_device *rtc,
194 struct rtc_wkalrm *alrm);
195 extern void rtc_update_irq(struct rtc_device *rtc,
196 unsigned long num, unsigned long events);
198 extern struct rtc_device *rtc_class_open(const char *name);
199 extern void rtc_class_close(struct rtc_device *rtc);
201 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
202 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
203 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
204 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
205 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
206 unsigned int enabled);
208 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
209 void rtc_aie_update_irq(void *private);
210 void rtc_uie_update_irq(void *private);
211 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
213 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
214 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
215 ktime_t expires, ktime_t period);
216 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
217 int rtc_read_offset(struct rtc_device *rtc, long *offset);
218 int rtc_set_offset(struct rtc_device *rtc, long offset);
219 void rtc_timer_do_work(struct work_struct *work);
220 int rtc_power_off_program(struct rtc_device *rtc);
222 static inline bool is_leap_year(unsigned int year)
223 {
224 return (!(year % 4) && (year % 100)) || !(year % 400);
225 }
227 /* Determine if we can call to driver to set the time. Drivers can only be
228 * called to set a second aligned time value, and the field set_offset_nsec
229 * specifies how far away from the second aligned time to call the driver.
230 *
231 * This also computes 'to_set' which is the time we are trying to set, and has
232 * a zero in tv_nsecs, such that:
233 * to_set - set_delay_nsec == now +/- FUZZ
234 *
235 */
236 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
237 struct timespec64 *to_set,
238 const struct timespec64 *now)
239 {
240 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
241 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
242 struct timespec64 delay = {.tv_sec = 0,
243 .tv_nsec = set_offset_nsec};
245 *to_set = timespec64_add(*now, delay);
247 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
248 to_set->tv_nsec = 0;
249 return true;
250 }
252 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
253 to_set->tv_sec++;
254 to_set->tv_nsec = 0;
255 return true;
256 }
257 return false;
258 }
260 #define rtc_register_device(device) \
261 __rtc_register_device(THIS_MODULE, device)
263 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
264 extern int rtc_hctosys_ret;
265 #else
266 #define rtc_hctosys_ret -ENODEV
267 #endif
269 #ifdef CONFIG_RTC_NVMEM
270 int rtc_nvmem_register(struct rtc_device *rtc,
271 struct nvmem_config *nvmem_config);
272 void rtc_nvmem_unregister(struct rtc_device *rtc);
273 #else
274 static inline int rtc_nvmem_register(struct rtc_device *rtc,
275 struct nvmem_config *nvmem_config)
276 {
277 return 0;
278 }
279 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
280 #endif
282 #endif /* _LINUX_RTC_H_ */