/*
* RTC subsystem, base class
*
* Copyright (C) 2005 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* class skeleton from drivers/hwmon/hwmon.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/of.h>
#include <linux/rtc.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include "rtc-core.h"
static DEFINE_IDA(rtc_ida);
struct class *rtc_class;
static void rtc_device_release(struct device *dev)
{
struct rtc_device *rtc = to_rtc_device(dev);
ida_simple_remove(&rtc_ida, rtc->id);
kfree(rtc);
}
#ifdef CONFIG_RTC_HCTOSYS_DEVICE
/* Result of the last RTC to system clock attempt. */
int rtc_hctosys_ret = -ENODEV;
#endif
#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
/*
* On suspend(), measure the delta between one RTC and the
* system's wall clock; restore it on resume().
*/
static struct timespec64 old_rtc, old_system, old_delta;
static int rtc_suspend(struct device *dev)
{
struct rtc_device *rtc = to_rtc_device(dev);
struct rtc_time tm;
struct timespec64 delta, delta_delta;
int err;
if (has_persistent_clock())
return 0;
if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
return 0;
/* snapshot the current RTC and system time at suspend*/
err = rtc_read_time(rtc, &tm);
if (err < 0) {
pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
return 0;
}
getnstimeofday64(&old_system);
old_rtc.tv_sec = rtc_tm_to_time64(&tm);
/*
* To avoid drift caused by repeated suspend/resumes,
* which each can add ~1 second drift error,
* try to compensate so the difference in system time
* and rtc time stays close to constant.
*/
delta = timespec64_sub(old_system, old_rtc);
delta_delta = timespec64_sub(delta, old_delta);
if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
/*
* if delta_delta is too large, assume time correction
* has occured and set old_delta to the current delta.
*/
old_delta = delta;
} else {
/* Otherwise try to adjust old_system to compensate */
old_system = timespec64_sub(old_system, delta_delta);
}
return 0;
}
static int rtc_resume(struct device *dev)
{
struct rtc_device *rtc = to_rtc_device(dev);
struct rtc_time tm;
struct timespec64 new_system, new_rtc;
struct timespec64 sleep_time;
int err;
if (has_persistent_clock())
return 0;
rtc_hctosys_ret = -ENODEV;
if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
return 0;
/* snapshot the current rtc and system time at resume */
getnstimeofday64(&new_system);
err = rtc_read_time(rtc, &tm);
if (err < 0) {
pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
return 0;
}
if (rtc_valid_tm(&tm) != 0) {
pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
return 0;
}
new_rtc.tv_sec = rtc_tm_to_time64(&tm);
new_rtc.tv_nsec = 0;
if (new_rtc.tv_sec < old_rtc.tv_sec) {
pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
return 0;
}
/* calculate the RTC time delta (sleep time)*/
sleep_time = timespec64_sub(new_rtc, old_rtc);
/*
* Since these RTC suspend/resume handlers are not called
* at the very end of suspend or the start of resume,
* some run-time may pass on either sides of the sleep time
* so subtract kernel run-time between rtc_suspend to rtc_resume
* to keep things accurate.
*/
sleep_time = timespec64_sub(sleep_time,
timespec64_sub(new_system, old_system));
if (sleep_time.tv_sec >= 0)
timekeeping_inject_sleeptime64(&sleep_time);
rtc_hctosys_ret = 0;
return 0;
}
static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
#else
#define RTC_CLASS_DEV_PM_OPS NULL
#endif
/**
* rtc_device_register - register w/ RTC class
* @dev: the device to register
*
* rtc_device_unregister() must be called when the class device is no
* longer needed.
*
* Returns the pointer to the new struct class device.
*/
struct rtc_device *rtc_device_register(const char *name, struct device *dev,
const struct rtc_class_ops *ops,
struct module *owner)
{
struct rtc_device *rtc;
struct rtc_wkalrm alrm;
int of_id = -1, id = -1, err;
if (dev->of_node)
of_id = of_alias_get_id(dev->of_node, "rtc");
else if (dev->parent && dev->parent->of_node)
of_id = of_alias_get_id(dev->parent->of_node, "rtc");
if (of_id >= 0) {
id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
GFP_KERNEL);
if (id < 0)
dev_warn(dev, "/aliases ID %d not available\n",
of_id);
}
if (id < 0) {
id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
if (id < 0) {
err = id;
goto exit;
}
}
rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
if (rtc == NULL) {
err = -ENOMEM;
goto exit_ida;
}
rtc->id = id;
rtc->ops = ops;
rtc->owner = owner;
rtc->irq_freq = 1;
rtc->max_user_freq = 64;
rtc->dev.parent = dev;
rtc->dev.class = rtc_class;
rtc->dev.release = rtc_device_release;
mutex_init(&rtc->ops_lock);
spin_lock_init(&rtc->irq_lock);
spin_lock_init(&rtc->irq_task_lock);
init_waitqueue_head(&rtc->irq_queue);
/* Init timerqueue */
timerqueue_init_head(&rtc->timerqueue);
INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
/* Init aie timer */
rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
/* Init uie timer */
rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
/* Init pie timer */
hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
rtc->pie_timer.function = rtc_pie_update_irq;
rtc->pie_enabled = 0;
/* Check to see if there is an ALARM already set in hw */
err = __rtc_read_alarm(rtc, &alrm);
if (!err && !rtc_valid_tm(&alrm.time))
rtc_initialize_alarm(rtc, &alrm);
strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
dev_set_name(&rtc->dev, "rtc%d", id);
rtc_dev_prepare(rtc);
err = device_register(&rtc->dev);
if (err) {
put_device(&rtc->dev);
goto exit_kfree;
}
rtc_dev_add_device(rtc);
rtc_sysfs_add_device(rtc);
rtc_proc_add_device(rtc);
dev_info(dev, "rtc core: registered %s as %s\n",
rtc->name, dev_name(&rtc->dev));
return rtc;
exit_kfree:
kfree(rtc);
exit_ida:
ida_simple_remove(&rtc_ida, id);
exit:
dev_err(dev, "rtc core: unable to register %s, err = %d\n",
name, err);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(rtc_device_register);
/**
* rtc_device_unregister - removes the previously registered RTC class device
*
* @rtc: the RTC class device to destroy
*/
void rtc_device_unregister(struct rtc_device *rtc)
{
if (get_device(&rtc->dev) != NULL) {
mutex_lock(&rtc->ops_lock);
/* remove innards of this RTC, then disable it, before
* letting any rtc_class_open() users access it again
*/
rtc_sysfs_del_device(rtc);
rtc_dev_del_device(rtc);
rtc_proc_del_device(rtc);
device_unregister(&rtc->dev);
rtc->ops = NULL;
mutex_unlock(&rtc->ops_lock);
put_device(&rtc->dev);
}
}
EXPORT_SYMBOL_GPL(rtc_device_unregister);
static void devm_rtc_device_release(struct device *dev, void *res)
{
struct rtc_device *rtc = *(struct rtc_device **)res;
rtc_device_unregister(rtc);
}
static int devm_rtc_device_match(struct device *dev, void *res, void *data)
{
struct rtc **r = res;
return *r == data;
}
/**
* devm_rtc_device_register - resource managed rtc_device_register()
* @dev: the device to register
* @name: the name of the device
* @ops: the rtc operations structure
* @owner: the module owner
*
* @return a struct rtc on success, or an ERR_PTR on error
*
* Managed rtc_device_register(). The rtc_device returned from this function
* are automatically freed on driver detach. See rtc_device_register()
* for more information.
*/
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 **ptr, *rtc;
ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
rtc = rtc_device_register(name, dev, ops, owner);
if (!IS_ERR(rtc)) {
*ptr = rtc;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return rtc;
}
EXPORT_SYMBOL_GPL(devm_rtc_device_register);
/**
* devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
* @dev: the device to unregister
* @rtc: the RTC class device to unregister
*
* Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
* function will not need to be called and the resource management code will
* ensure that the resource is freed.
*/
void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
{
int rc;
rc = devres_release(dev, devm_rtc_device_release,
devm_rtc_device_match, rtc);
WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
static int __init rtc_init(void)
{
rtc_class = class_create(THIS_MODULE, "rtc");
if (IS_ERR(rtc_class)) {
pr_err("couldn't create class\n");
return PTR_ERR(rtc_class);
}
rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
rtc_dev_init();
rtc_sysfs_init(rtc_class);
return 0;
}
static void __exit rtc_exit(void)
{
rtc_dev_exit();
class_destroy(rtc_class);
ida_destroy(&rtc_ida);
}
subsys_initcall(rtc_init);
module_exit(rtc_exit);
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("RTC class support");
MODULE_LICENSE("GPL");
