| /* |
| * 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 (timekeeping_rtc_skipsuspend()) |
| 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 (timekeeping_rtc_skipresume()) |
| 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; |
| } |
| |
| 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"); |