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
rtc_time_to_tm(unsigned long time,struct rtc_time * tm)37 static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
38 {
39 rtc_time64_to_tm(time, tm);
40 }
41
rtc_tm_to_time(struct rtc_time * tm,unsigned long * time)42 static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
43 {
44 *time = rtc_tm_to_time64(tm);
45
46 return 0;
47 }
48
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>
56
57 extern struct class *rtc_class;
58
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()
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 (*alarm_irq_enable)(struct device *, unsigned int enabled);
83 int (*read_offset)(struct device *, long *offset);
84 int (*set_offset)(struct device *, long offset);
85 };
86
87 struct rtc_device;
88
89 struct rtc_timer {
90 struct timerqueue_node node;
91 ktime_t period;
92 void (*func)(struct rtc_device *rtc);
93 struct rtc_device *rtc;
94 int enabled;
95 };
96
97 /* flags */
98 #define RTC_DEV_BUSY 0
99
100 struct rtc_device {
101 struct device dev;
102 struct module *owner;
103
104 int id;
105
106 const struct rtc_class_ops *ops;
107 struct mutex ops_lock;
108
109 struct cdev char_dev;
110 unsigned long flags;
111
112 unsigned long irq_data;
113 spinlock_t irq_lock;
114 wait_queue_head_t irq_queue;
115 struct fasync_struct *async_queue;
116
117 int irq_freq;
118 int max_user_freq;
119
120 struct timerqueue_head timerqueue;
121 struct rtc_timer aie_timer;
122 struct rtc_timer uie_rtctimer;
123 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
124 int pie_enabled;
125 struct work_struct irqwork;
126 /* Some hardware can't support UIE mode */
127 int uie_unsupported;
128
129 /* Number of nsec it takes to set the RTC clock. This influences when
130 * the set ops are called. An offset:
131 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
132 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
133 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
134 */
135 long set_offset_nsec;
136
137 bool registered;
138
139 /* Old ABI support */
140 bool nvram_old_abi;
141 struct bin_attribute *nvram;
142
143 time64_t range_min;
144 timeu64_t range_max;
145 time64_t start_secs;
146 time64_t offset_secs;
147 bool set_start_time;
148
149 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
150 struct work_struct uie_task;
151 struct timer_list uie_timer;
152 /* Those fields are protected by rtc->irq_lock */
153 unsigned int oldsecs;
154 unsigned int uie_irq_active:1;
155 unsigned int stop_uie_polling:1;
156 unsigned int uie_task_active:1;
157 unsigned int uie_timer_active:1;
158 #endif
159 };
160 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
161
162 /* useful timestamps */
163 #define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */
164 #define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
165 #define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
166 #define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
167 #define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
168
169 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
170 const char *name,
171 const struct rtc_class_ops *ops,
172 struct module *owner);
173 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
174 int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
175
176 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
177 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
178 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
179 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
180 extern int rtc_read_alarm(struct rtc_device *rtc,
181 struct rtc_wkalrm *alrm);
182 extern int rtc_set_alarm(struct rtc_device *rtc,
183 struct rtc_wkalrm *alrm);
184 extern int rtc_initialize_alarm(struct rtc_device *rtc,
185 struct rtc_wkalrm *alrm);
186 extern void rtc_update_irq(struct rtc_device *rtc,
187 unsigned long num, unsigned long events);
188
189 extern struct rtc_device *rtc_class_open(const char *name);
190 extern void rtc_class_close(struct rtc_device *rtc);
191
192 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
193 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
194 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
195 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
196 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
197 unsigned int enabled);
198
199 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
200 void rtc_aie_update_irq(struct rtc_device *rtc);
201 void rtc_uie_update_irq(struct rtc_device *rtc);
202 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
203
204 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
205 struct rtc_device *rtc);
206 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
207 ktime_t expires, ktime_t period);
208 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
209 int rtc_read_offset(struct rtc_device *rtc, long *offset);
210 int rtc_set_offset(struct rtc_device *rtc, long offset);
211 void rtc_timer_do_work(struct work_struct *work);
212
is_leap_year(unsigned int year)213 static inline bool is_leap_year(unsigned int year)
214 {
215 return (!(year % 4) && (year % 100)) || !(year % 400);
216 }
217
218 /* Determine if we can call to driver to set the time. Drivers can only be
219 * called to set a second aligned time value, and the field set_offset_nsec
220 * specifies how far away from the second aligned time to call the driver.
221 *
222 * This also computes 'to_set' which is the time we are trying to set, and has
223 * a zero in tv_nsecs, such that:
224 * to_set - set_delay_nsec == now +/- FUZZ
225 *
226 */
rtc_tv_nsec_ok(s64 set_offset_nsec,struct timespec64 * to_set,const struct timespec64 * now)227 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
228 struct timespec64 *to_set,
229 const struct timespec64 *now)
230 {
231 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
232 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
233 struct timespec64 delay = {.tv_sec = 0,
234 .tv_nsec = set_offset_nsec};
235
236 *to_set = timespec64_add(*now, delay);
237
238 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
239 to_set->tv_nsec = 0;
240 return true;
241 }
242
243 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
244 to_set->tv_sec++;
245 to_set->tv_nsec = 0;
246 return true;
247 }
248 return false;
249 }
250
251 #define rtc_register_device(device) \
252 __rtc_register_device(THIS_MODULE, device)
253
254 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
255 extern int rtc_hctosys_ret;
256 #else
257 #define rtc_hctosys_ret -ENODEV
258 #endif
259
260 #ifdef CONFIG_RTC_NVMEM
261 int rtc_nvmem_register(struct rtc_device *rtc,
262 struct nvmem_config *nvmem_config);
263 void rtc_nvmem_unregister(struct rtc_device *rtc);
264 #else
rtc_nvmem_register(struct rtc_device * rtc,struct nvmem_config * nvmem_config)265 static inline int rtc_nvmem_register(struct rtc_device *rtc,
266 struct nvmem_config *nvmem_config)
267 {
268 return 0;
269 }
rtc_nvmem_unregister(struct rtc_device * rtc)270 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
271 #endif
272
273 #ifdef CONFIG_RTC_INTF_SYSFS
274 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
275 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
276 #else
277 static inline
rtc_add_group(struct rtc_device * rtc,const struct attribute_group * grp)278 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
279 {
280 return 0;
281 }
282
283 static inline
rtc_add_groups(struct rtc_device * rtc,const struct attribute_group ** grps)284 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
285 {
286 return 0;
287 }
288 #endif
289 #endif /* _LINUX_RTC_H_ */
290
