rtc.h

  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 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 */
 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	int (*param_get)(struct device *, struct rtc_param *param);
 70	int (*param_set)(struct device *, struct rtc_param *param);
 71};
 72
 73struct rtc_device;
 74
 75struct 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
 87struct 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_EPOCH_GPS		315964800LL /* 1980-01-06 00:00:00 */
174#define RTC_TIMESTAMP_BEGIN_2000	946684800LL /* 2000-01-01 00:00:00 */
175#define RTC_TIMESTAMP_END_2063		2966371199LL /* 2063-12-31 23:59:59 */
176#define RTC_TIMESTAMP_END_2079		3471292799LL /* 2079-12-31 23:59:59 */
177#define RTC_TIMESTAMP_END_2099		4102444799LL /* 2099-12-31 23:59:59 */
178#define RTC_TIMESTAMP_END_2199		7258118399LL /* 2199-12-31 23:59:59 */
179#define RTC_TIMESTAMP_END_9999		253402300799LL /* 9999-12-31 23:59:59 */
180
181extern struct rtc_device *devm_rtc_device_register(struct device *dev,
182					const char *name,
183					const struct rtc_class_ops *ops,
184					struct module *owner);
185struct rtc_device *devm_rtc_allocate_device(struct device *dev);
186int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
187
188extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
189extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
190int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
191extern int rtc_read_alarm(struct rtc_device *rtc,
192			struct rtc_wkalrm *alrm);
193extern int rtc_set_alarm(struct rtc_device *rtc,
194				struct rtc_wkalrm *alrm);
195extern int rtc_initialize_alarm(struct rtc_device *rtc,
196				struct rtc_wkalrm *alrm);
197extern void rtc_update_irq(struct rtc_device *rtc,
198			unsigned long num, unsigned long events);
199
200extern struct rtc_device *rtc_class_open(const char *name);
201extern void rtc_class_close(struct rtc_device *rtc);
202
203extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
204extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
205extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
206extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
207extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
208						unsigned int enabled);
209
210void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
211void rtc_aie_update_irq(struct rtc_device *rtc);
212void rtc_uie_update_irq(struct rtc_device *rtc);
213enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
214
215void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
216		    struct rtc_device *rtc);
217int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
218		    ktime_t expires, ktime_t period);
219void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
220int rtc_read_offset(struct rtc_device *rtc, long *offset);
221int rtc_set_offset(struct rtc_device *rtc, long offset);
222void rtc_timer_do_work(struct work_struct *work);
223
224static inline bool is_leap_year(unsigned int year)
225{
226	return (!(year % 4) && (year % 100)) || !(year % 400);
227}
228
229/**
230 * rtc_bound_alarmtime() - Return alarm time bound by rtc limit
231 * @rtc: Pointer to rtc device structure
232 * @requested: Requested alarm timeout
233 *
234 * Return: Alarm timeout bound by maximum alarm time supported by rtc.
235 */
236static inline ktime_t rtc_bound_alarmtime(struct rtc_device *rtc,
237					  ktime_t requested)
238{
239	if (rtc->alarm_offset_max &&
240	    rtc->alarm_offset_max * MSEC_PER_SEC < ktime_to_ms(requested))
241		return ms_to_ktime(rtc->alarm_offset_max * MSEC_PER_SEC);
242
243	return requested;
244}
245
246#define devm_rtc_register_device(device) \
247	__devm_rtc_register_device(THIS_MODULE, device)
248
249#ifdef CONFIG_RTC_HCTOSYS_DEVICE
250extern int rtc_hctosys_ret;
251#else
252#define rtc_hctosys_ret -ENODEV
253#endif
254
255#ifdef CONFIG_RTC_NVMEM
256int devm_rtc_nvmem_register(struct rtc_device *rtc,
257			    struct nvmem_config *nvmem_config);
258#else
259static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
260					  struct nvmem_config *nvmem_config)
261{
262	return 0;
263}
264#endif
265
266#ifdef CONFIG_RTC_INTF_SYSFS
267int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
268int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
269#else
270static inline
271int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
272{
273	return 0;
274}
275
276static inline
277int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
278{
279	return 0;
280}
281#endif
282#endif /* _LINUX_RTC_H_ */