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linux-next/include/linux/rtc.h
Alexandre Belloni 0d20e9fb12 rtc: add BSM parameter
BSM or Backup Switch Mode is a common feature on RTCs, allowing to select
how the RTC will decide when to switch from its primary power supply to the
backup power supply. It is necessary to be able to set it from userspace as
there are uses cases where it has to be done dynamically.

Supported values are:
  RTC_BSM_DISABLED: disabled
  RTC_BSM_DIRECT: switching will happen as soon as Vbackup > Vdd
  RTC_BSM_LEVEL: switching will happen around a threshold, usually with an
  hysteresis
  RTC_BSM_STANDBY: switching will not happen until Vdd > Vbackup, this is
  useful to ensure the RTC doesn't draw any power until the device is first
  powered on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211018151933.76865-6-alexandre.belloni@bootlin.com
2021-10-18 17:20:50 +02:00

266 lines
8.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Generic RTC interface.
* This version contains the part of the user interface to the Real Time Clock
* service. It is used with both the legacy mc146818 and also EFI
* Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
* from <linux/mc146818rtc.h> to this file for 2.4 kernels.
*
* Copyright (C) 1999 Hewlett-Packard Co.
* Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
*/
#ifndef _LINUX_RTC_H_
#define _LINUX_RTC_H_
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/nvmem-provider.h>
#include <uapi/linux/rtc.h>
extern int rtc_month_days(unsigned int month, unsigned int year);
extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
extern int rtc_valid_tm(struct rtc_time *tm);
extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
ktime_t rtc_tm_to_ktime(struct rtc_time tm);
struct rtc_time rtc_ktime_to_tm(ktime_t kt);
/*
* rtc_tm_sub - Return the difference in seconds.
*/
static inline time64_t rtc_tm_sub(struct rtc_time *lhs, struct rtc_time *rhs)
{
return rtc_tm_to_time64(lhs) - rtc_tm_to_time64(rhs);
}
#include <linux/device.h>
#include <linux/seq_file.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/timerqueue.h>
#include <linux/workqueue.h>
extern struct class *rtc_class;
/*
* For these RTC methods the device parameter is the physical device
* on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
* was passed to rtc_device_register(). Its driver_data normally holds
* device state, including the rtc_device pointer for the RTC.
*
* Most of these methods are called with rtc_device.ops_lock held,
* through the rtc_*(struct rtc_device *, ...) calls.
*
* The (current) exceptions are mostly filesystem hooks:
* - the proc() hook for procfs
*/
struct rtc_class_ops {
int (*ioctl)(struct device *, unsigned int, unsigned long);
int (*read_time)(struct device *, struct rtc_time *);
int (*set_time)(struct device *, struct rtc_time *);
int (*read_alarm)(struct device *, struct rtc_wkalrm *);
int (*set_alarm)(struct device *, struct rtc_wkalrm *);
int (*proc)(struct device *, struct seq_file *);
int (*alarm_irq_enable)(struct device *, unsigned int enabled);
int (*read_offset)(struct device *, long *offset);
int (*set_offset)(struct device *, long offset);
int (*param_get)(struct device *, struct rtc_param *param);
int (*param_set)(struct device *, struct rtc_param *param);
};
struct rtc_device;
struct rtc_timer {
struct timerqueue_node node;
ktime_t period;
void (*func)(struct rtc_device *rtc);
struct rtc_device *rtc;
int enabled;
};
/* flags */
#define RTC_DEV_BUSY 0
#define RTC_NO_CDEV 1
struct rtc_device {
struct device dev;
struct module *owner;
int id;
const struct rtc_class_ops *ops;
struct mutex ops_lock;
struct cdev char_dev;
unsigned long flags;
unsigned long irq_data;
spinlock_t irq_lock;
wait_queue_head_t irq_queue;
struct fasync_struct *async_queue;
int irq_freq;
int max_user_freq;
struct timerqueue_head timerqueue;
struct rtc_timer aie_timer;
struct rtc_timer uie_rtctimer;
struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
int pie_enabled;
struct work_struct irqwork;
/* Some hardware can't support UIE mode */
int uie_unsupported;
/*
* This offset specifies the update timing of the RTC.
*
* tsched t1 write(t2.tv_sec - 1sec)) t2 RTC increments seconds
*
* The offset defines how tsched is computed so that the write to
* the RTC (t2.tv_sec - 1sec) is correct versus the time required
* for the transport of the write and the time which the RTC needs
* to increment seconds the first time after the write (t2).
*
* For direct accessible RTCs tsched ~= t1 because the write time
* is negligible. For RTCs behind slow busses the transport time is
* significant and has to be taken into account.
*
* The time between the write (t1) and the first increment after
* the write (t2) is RTC specific. For a MC146818 RTC it's 500ms,
* for many others it's exactly 1 second. Consult the datasheet.
*
* The value of this offset is also used to calculate the to be
* written value (t2.tv_sec - 1sec) at tsched.
*
* The default value for this is NSEC_PER_SEC + 10 msec default
* transport time. The offset can be adjusted by drivers so the
* calculation for the to be written value at tsched becomes
* correct:
*
* newval = tsched + set_offset_nsec - NSEC_PER_SEC
* and (tsched + set_offset_nsec) % NSEC_PER_SEC == 0
*/
unsigned long set_offset_nsec;
unsigned long features[BITS_TO_LONGS(RTC_FEATURE_CNT)];
time64_t range_min;
timeu64_t range_max;
time64_t start_secs;
time64_t offset_secs;
bool set_start_time;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
/* Those fields are protected by rtc->irq_lock */
unsigned int oldsecs;
unsigned int uie_irq_active:1;
unsigned int stop_uie_polling:1;
unsigned int uie_task_active:1;
unsigned int uie_timer_active:1;
#endif
};
#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
#define rtc_lock(d) mutex_lock(&d->ops_lock)
#define rtc_unlock(d) mutex_unlock(&d->ops_lock)
/* useful timestamps */
#define RTC_TIMESTAMP_BEGIN_0000 -62167219200ULL /* 0000-01-01 00:00:00 */
#define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */
#define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
#define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
#define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */
#define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
#define RTC_TIMESTAMP_END_2199 7258118399LL /* 2199-12-31 23:59:59 */
#define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
extern struct rtc_device *devm_rtc_device_register(struct device *dev,
const char *name,
const struct rtc_class_ops *ops,
struct module *owner);
struct rtc_device *devm_rtc_allocate_device(struct device *dev);
int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc);
extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
extern int rtc_read_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_set_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_initialize_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern void rtc_update_irq(struct rtc_device *rtc,
unsigned long num, unsigned long events);
extern struct rtc_device *rtc_class_open(const char *name);
extern void rtc_class_close(struct rtc_device *rtc);
extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
unsigned int enabled);
void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
void rtc_aie_update_irq(struct rtc_device *rtc);
void rtc_uie_update_irq(struct rtc_device *rtc);
enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
struct rtc_device *rtc);
int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
ktime_t expires, ktime_t period);
void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
int rtc_read_offset(struct rtc_device *rtc, long *offset);
int rtc_set_offset(struct rtc_device *rtc, long offset);
void rtc_timer_do_work(struct work_struct *work);
static inline bool is_leap_year(unsigned int year)
{
return (!(year % 4) && (year % 100)) || !(year % 400);
}
#define devm_rtc_register_device(device) \
__devm_rtc_register_device(THIS_MODULE, device)
#ifdef CONFIG_RTC_HCTOSYS_DEVICE
extern int rtc_hctosys_ret;
#else
#define rtc_hctosys_ret -ENODEV
#endif
#ifdef CONFIG_RTC_NVMEM
int devm_rtc_nvmem_register(struct rtc_device *rtc,
struct nvmem_config *nvmem_config);
#else
static inline int devm_rtc_nvmem_register(struct rtc_device *rtc,
struct nvmem_config *nvmem_config)
{
return 0;
}
#endif
#ifdef CONFIG_RTC_INTF_SYSFS
int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
#else
static inline
int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
{
return 0;
}
static inline
int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
{
return 0;
}
#endif
#endif /* _LINUX_RTC_H_ */