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![Alexandre Belloni](/assets/img/avatar_default.png)
rtc_device_unregister is gone since commit fdcfd85433
("rtc: rework
rtc_register_device() resource management"). Remove its documentation.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210202112219.3610853-2-alexandre.belloni@bootlin.com
469 lines
12 KiB
C
469 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#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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mutex_destroy(&rtc->ops_lock);
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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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/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
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* whether it stores the most close value or the value with partial
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* seconds truncated. However, it is important that we use it to store
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* the truncated value. This is because otherwise it is necessary,
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* in an rtc sync function, to read both xtime.tv_sec and
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* xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
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* of >32bits is not possible. So storing the most close value would
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* slow down the sync API. So here we have the truncated value and
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* the best guess is to add 0.5s.
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*/
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static void rtc_hctosys(struct rtc_device *rtc)
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{
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int err;
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struct rtc_time tm;
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struct timespec64 tv64 = {
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.tv_nsec = NSEC_PER_SEC >> 1,
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};
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err = rtc_read_time(rtc, &tm);
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if (err) {
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dev_err(rtc->dev.parent,
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"hctosys: unable to read the hardware clock\n");
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goto err_read;
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}
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tv64.tv_sec = rtc_tm_to_time64(&tm);
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#if BITS_PER_LONG == 32
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if (tv64.tv_sec > INT_MAX) {
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err = -ERANGE;
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goto err_read;
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}
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#endif
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err = do_settimeofday64(&tv64);
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dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
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&tm, (long long)tv64.tv_sec);
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err_read:
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rtc_hctosys_ret = err;
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}
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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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ktime_get_real_ts64(&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 occurred 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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ktime_get_real_ts64(&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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/* Ensure the caller will set the id before releasing the device */
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static struct rtc_device *rtc_allocate_device(void)
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{
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struct rtc_device *rtc;
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rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
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if (!rtc)
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return NULL;
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device_initialize(&rtc->dev);
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/*
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* Drivers can revise this default after allocating the device.
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* The default is what most RTCs do: Increment seconds exactly one
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* second after the write happened. This adds a default transport
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* time of 5ms which is at least halfways close to reality.
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*/
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rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
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rtc->irq_freq = 1;
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rtc->max_user_freq = 64;
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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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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, rtc);
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/* Init uie timer */
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rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, 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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set_bit(RTC_FEATURE_ALARM, rtc->features);
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return rtc;
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}
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static int rtc_device_get_id(struct device *dev)
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{
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int of_id = -1, id = -1;
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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, GFP_KERNEL);
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if (id < 0)
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dev_warn(dev, "/aliases ID %d not available\n", 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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return id;
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}
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static void rtc_device_get_offset(struct rtc_device *rtc)
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{
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time64_t range_secs;
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u32 start_year;
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int ret;
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/*
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* If RTC driver did not implement the range of RTC hardware device,
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* then we can not expand the RTC range by adding or subtracting one
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* offset.
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*/
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if (rtc->range_min == rtc->range_max)
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return;
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ret = device_property_read_u32(rtc->dev.parent, "start-year",
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&start_year);
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if (!ret) {
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rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
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rtc->set_start_time = true;
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}
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/*
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* If user did not implement the start time for RTC driver, then no
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* need to expand the RTC range.
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*/
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if (!rtc->set_start_time)
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return;
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range_secs = rtc->range_max - rtc->range_min + 1;
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/*
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* If the start_secs is larger than the maximum seconds (rtc->range_max)
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* supported by RTC hardware or the maximum seconds of new expanded
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* range (start_secs + rtc->range_max - rtc->range_min) is less than
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* rtc->range_min, which means the minimum seconds (rtc->range_min) of
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* RTC hardware will be mapped to start_secs by adding one offset, so
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* the offset seconds calculation formula should be:
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* rtc->offset_secs = rtc->start_secs - rtc->range_min;
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*
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* If the start_secs is larger than the minimum seconds (rtc->range_min)
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* supported by RTC hardware, then there is one region is overlapped
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* between the original RTC hardware range and the new expanded range,
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* and this overlapped region do not need to be mapped into the new
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* expanded range due to it is valid for RTC device. So the minimum
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* seconds of RTC hardware (rtc->range_min) should be mapped to
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* rtc->range_max + 1, then the offset seconds formula should be:
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* rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
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*
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* If the start_secs is less than the minimum seconds (rtc->range_min),
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* which is similar to case 2. So the start_secs should be mapped to
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* start_secs + rtc->range_max - rtc->range_min + 1, then the
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* offset seconds formula should be:
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* rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
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*
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* Otherwise the offset seconds should be 0.
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*/
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if (rtc->start_secs > rtc->range_max ||
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rtc->start_secs + range_secs - 1 < rtc->range_min)
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rtc->offset_secs = rtc->start_secs - rtc->range_min;
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else if (rtc->start_secs > rtc->range_min)
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rtc->offset_secs = range_secs;
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else if (rtc->start_secs < rtc->range_min)
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rtc->offset_secs = -range_secs;
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else
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rtc->offset_secs = 0;
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}
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static void devm_rtc_unregister_device(void *data)
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{
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struct rtc_device *rtc = data;
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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_proc_del_device(rtc);
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cdev_device_del(&rtc->char_dev, &rtc->dev);
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rtc->ops = NULL;
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mutex_unlock(&rtc->ops_lock);
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}
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static void devm_rtc_release_device(void *res)
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{
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struct rtc_device *rtc = res;
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put_device(&rtc->dev);
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}
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struct rtc_device *devm_rtc_allocate_device(struct device *dev)
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{
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struct rtc_device *rtc;
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int id, err;
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id = rtc_device_get_id(dev);
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if (id < 0)
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return ERR_PTR(id);
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rtc = rtc_allocate_device();
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if (!rtc) {
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ida_simple_remove(&rtc_ida, id);
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return ERR_PTR(-ENOMEM);
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}
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rtc->id = id;
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rtc->dev.parent = dev;
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dev_set_name(&rtc->dev, "rtc%d", id);
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err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
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if (err)
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return ERR_PTR(err);
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return rtc;
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}
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EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
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int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
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{
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struct rtc_wkalrm alrm;
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int err;
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if (!rtc->ops) {
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dev_dbg(&rtc->dev, "no ops set\n");
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return -EINVAL;
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}
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if (!rtc->ops->set_alarm)
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clear_bit(RTC_FEATURE_ALARM, rtc->features);
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rtc->owner = owner;
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rtc_device_get_offset(rtc);
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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 = cdev_device_add(&rtc->char_dev, &rtc->dev);
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if (err)
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dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
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MAJOR(rtc->dev.devt), rtc->id);
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else
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dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
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MAJOR(rtc->dev.devt), rtc->id);
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rtc_proc_add_device(rtc);
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dev_info(rtc->dev.parent, "registered as %s\n",
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dev_name(&rtc->dev));
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#ifdef CONFIG_RTC_HCTOSYS_DEVICE
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if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
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rtc_hctosys(rtc);
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#endif
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return devm_add_action_or_reset(rtc->dev.parent,
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devm_rtc_unregister_device, rtc);
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}
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EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
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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 (unused)
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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.
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* This function is deprecated, use devm_rtc_allocate_device and
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* rtc_register_device instead
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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 *rtc;
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int err;
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rtc = devm_rtc_allocate_device(dev);
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if (IS_ERR(rtc))
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return rtc;
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rtc->ops = ops;
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err = __devm_rtc_register_device(owner, rtc);
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if (err)
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return ERR_PTR(err);
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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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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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