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