Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1086 insertions, 0 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
new file mode 100644
index 000000000..3d0fbc644
--- /dev/null
+++ b/drivers/rtc/interface.c
@@ -0,0 +1,1086 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, interface functions
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ */
+
+#include <linux/rtc.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/log2.h>
+#include <linux/workqueue.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rtc.h>
+
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
+
+static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	time64_t secs;
+
+	if (!rtc->offset_secs)
+		return;
+
+	secs = rtc_tm_to_time64(tm);
+
+	/*
+	 * Since the reading time values from RTC device are always in the RTC
+	 * original valid range, but we need to skip the overlapped region
+	 * between expanded range and original range, which is no need to add
+	 * the offset.
+	 */
+	if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
+	    (rtc->start_secs < rtc->range_min &&
+	     secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
+		return;
+
+	rtc_time64_to_tm(secs + rtc->offset_secs, tm);
+}
+
+static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	time64_t secs;
+
+	if (!rtc->offset_secs)
+		return;
+
+	secs = rtc_tm_to_time64(tm);
+
+	/*
+	 * If the setting time values are in the valid range of RTC hardware
+	 * device, then no need to subtract the offset when setting time to RTC
+	 * device. Otherwise we need to subtract the offset to make the time
+	 * values are valid for RTC hardware device.
+	 */
+	if (secs >= rtc->range_min && secs <= rtc->range_max)
+		return;
+
+	rtc_time64_to_tm(secs - rtc->offset_secs, tm);
+}
+
+static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	if (rtc->range_min != rtc->range_max) {
+		time64_t time = rtc_tm_to_time64(tm);
+		time64_t range_min = rtc->set_start_time ? rtc->start_secs :
+			rtc->range_min;
+		timeu64_t range_max = rtc->set_start_time ?
+			(rtc->start_secs + rtc->range_max - rtc->range_min) :
+			rtc->range_max;
+
+		if (time < range_min || time > range_max)
+			return -ERANGE;
+	}
+
+	return 0;
+}
+
+static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err;
+
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!rtc->ops->read_time) {
+		err = -EINVAL;
+	} else {
+		memset(tm, 0, sizeof(struct rtc_time));
+		err = rtc->ops->read_time(rtc->dev.parent, tm);
+		if (err < 0) {
+			dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
+				err);
+			return err;
+		}
+
+		rtc_add_offset(rtc, tm);
+
+		err = rtc_valid_tm(tm);
+		if (err < 0)
+			dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
+	}
+	return err;
+}
+
+int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	err = __rtc_read_time(rtc, tm);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_time(rtc_tm_to_time64(tm), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_time);
+
+int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	int err, uie;
+
+	err = rtc_valid_tm(tm);
+	if (err != 0)
+		return err;
+
+	err = rtc_valid_range(rtc, tm);
+	if (err)
+		return err;
+
+	rtc_subtract_offset(rtc, tm);
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+	uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
+#else
+	uie = rtc->uie_rtctimer.enabled;
+#endif
+	if (uie) {
+		err = rtc_update_irq_enable(rtc, 0);
+		if (err)
+			return err;
+	}
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (rtc->ops->set_time)
+		err = rtc->ops->set_time(rtc->dev.parent, tm);
+	else
+		err = -EINVAL;
+
+	pm_stay_awake(rtc->dev.parent);
+	mutex_unlock(&rtc->ops_lock);
+	/* A timer might have just expired */
+	schedule_work(&rtc->irqwork);
+
+	if (uie) {
+		err = rtc_update_irq_enable(rtc, 1);
+		if (err)
+			return err;
+	}
+
+	trace_rtc_set_time(rtc_tm_to_time64(tm), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_time);
+
+static int rtc_read_alarm_internal(struct rtc_device *rtc,
+				   struct rtc_wkalrm *alarm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
+		err = -EINVAL;
+	} else {
+		alarm->enabled = 0;
+		alarm->pending = 0;
+		alarm->time.tm_sec = -1;
+		alarm->time.tm_min = -1;
+		alarm->time.tm_hour = -1;
+		alarm->time.tm_mday = -1;
+		alarm->time.tm_mon = -1;
+		alarm->time.tm_year = -1;
+		alarm->time.tm_wday = -1;
+		alarm->time.tm_yday = -1;
+		alarm->time.tm_isdst = -1;
+		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+
+int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_time before, now;
+	int first_time = 1;
+	time64_t t_now, t_alm;
+	enum { none, day, month, year } missing = none;
+	unsigned int days;
+
+	/* The lower level RTC driver may return -1 in some fields,
+	 * creating invalid alarm->time values, for reasons like:
+	 *
+	 *   - The hardware may not be capable of filling them in;
+	 *     many alarms match only on time-of-day fields, not
+	 *     day/month/year calendar data.
+	 *
+	 *   - Some hardware uses illegal values as "wildcard" match
+	 *     values, which non-Linux firmware (like a BIOS) may try
+	 *     to set up as e.g. "alarm 15 minutes after each hour".
+	 *     Linux uses only oneshot alarms.
+	 *
+	 * When we see that here, we deal with it by using values from
+	 * a current RTC timestamp for any missing (-1) values.  The
+	 * RTC driver prevents "periodic alarm" modes.
+	 *
+	 * But this can be racey, because some fields of the RTC timestamp
+	 * may have wrapped in the interval since we read the RTC alarm,
+	 * which would lead to us inserting inconsistent values in place
+	 * of the -1 fields.
+	 *
+	 * Reading the alarm and timestamp in the reverse sequence
+	 * would have the same race condition, and not solve the issue.
+	 *
+	 * So, we must first read the RTC timestamp,
+	 * then read the RTC alarm value,
+	 * and then read a second RTC timestamp.
+	 *
+	 * If any fields of the second timestamp have changed
+	 * when compared with the first timestamp, then we know
+	 * our timestamp may be inconsistent with that used by
+	 * the low-level rtc_read_alarm_internal() function.
+	 *
+	 * So, when the two timestamps disagree, we just loop and do
+	 * the process again to get a fully consistent set of values.
+	 *
+	 * This could all instead be done in the lower level driver,
+	 * but since more than one lower level RTC implementation needs it,
+	 * then it's probably best best to do it here instead of there..
+	 */
+
+	/* Get the "before" timestamp */
+	err = rtc_read_time(rtc, &before);
+	if (err < 0)
+		return err;
+	do {
+		if (!first_time)
+			memcpy(&before, &now, sizeof(struct rtc_time));
+		first_time = 0;
+
+		/* get the RTC alarm values, which may be incomplete */
+		err = rtc_read_alarm_internal(rtc, alarm);
+		if (err)
+			return err;
+
+		/* full-function RTCs won't have such missing fields */
+		if (rtc_valid_tm(&alarm->time) == 0) {
+			rtc_add_offset(rtc, &alarm->time);
+			return 0;
+		}
+
+		/* get the "after" timestamp, to detect wrapped fields */
+		err = rtc_read_time(rtc, &now);
+		if (err < 0)
+			return err;
+
+		/* note that tm_sec is a "don't care" value here: */
+	} while (before.tm_min  != now.tm_min ||
+		 before.tm_hour != now.tm_hour ||
+		 before.tm_mon  != now.tm_mon ||
+		 before.tm_year != now.tm_year);
+
+	/* Fill in the missing alarm fields using the timestamp; we
+	 * know there's at least one since alarm->time is invalid.
+	 */
+	if (alarm->time.tm_sec == -1)
+		alarm->time.tm_sec = now.tm_sec;
+	if (alarm->time.tm_min == -1)
+		alarm->time.tm_min = now.tm_min;
+	if (alarm->time.tm_hour == -1)
+		alarm->time.tm_hour = now.tm_hour;
+
+	/* For simplicity, only support date rollover for now */
+	if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
+		alarm->time.tm_mday = now.tm_mday;
+		missing = day;
+	}
+	if ((unsigned int)alarm->time.tm_mon >= 12) {
+		alarm->time.tm_mon = now.tm_mon;
+		if (missing == none)
+			missing = month;
+	}
+	if (alarm->time.tm_year == -1) {
+		alarm->time.tm_year = now.tm_year;
+		if (missing == none)
+			missing = year;
+	}
+
+	/* Can't proceed if alarm is still invalid after replacing
+	 * missing fields.
+	 */
+	err = rtc_valid_tm(&alarm->time);
+	if (err)
+		goto done;
+
+	/* with luck, no rollover is needed */
+	t_now = rtc_tm_to_time64(&now);
+	t_alm = rtc_tm_to_time64(&alarm->time);
+	if (t_now < t_alm)
+		goto done;
+
+	switch (missing) {
+	/* 24 hour rollover ... if it's now 10am Monday, an alarm that
+	 * that will trigger at 5am will do so at 5am Tuesday, which
+	 * could also be in the next month or year.  This is a common
+	 * case, especially for PCs.
+	 */
+	case day:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
+		t_alm += 24 * 60 * 60;
+		rtc_time64_to_tm(t_alm, &alarm->time);
+		break;
+
+	/* Month rollover ... if it's the 31th, an alarm on the 3rd will
+	 * be next month.  An alarm matching on the 30th, 29th, or 28th
+	 * may end up in the month after that!  Many newer PCs support
+	 * this type of alarm.
+	 */
+	case month:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
+		do {
+			if (alarm->time.tm_mon < 11) {
+				alarm->time.tm_mon++;
+			} else {
+				alarm->time.tm_mon = 0;
+				alarm->time.tm_year++;
+			}
+			days = rtc_month_days(alarm->time.tm_mon,
+					      alarm->time.tm_year);
+		} while (days < alarm->time.tm_mday);
+		break;
+
+	/* Year rollover ... easy except for leap years! */
+	case year:
+		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
+		do {
+			alarm->time.tm_year++;
+		} while (!is_leap_year(alarm->time.tm_year + 1900) &&
+			 rtc_valid_tm(&alarm->time) != 0);
+		break;
+
+	default:
+		dev_warn(&rtc->dev, "alarm rollover not handled\n");
+	}
+
+	err = rtc_valid_tm(&alarm->time);
+
+done:
+	if (err)
+		dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
+			 &alarm->time);
+
+	return err;
+}
+
+int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+	if (!rtc->ops) {
+		err = -ENODEV;
+	} else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) {
+		err = -EINVAL;
+	} else {
+		memset(alarm, 0, sizeof(struct rtc_wkalrm));
+		alarm->enabled = rtc->aie_timer.enabled;
+		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
+	}
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_alarm);
+
+static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	struct rtc_time tm;
+	time64_t now, scheduled;
+	int err;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err)
+		return err;
+
+	scheduled = rtc_tm_to_time64(&alarm->time);
+
+	/* Make sure we're not setting alarms in the past */
+	err = __rtc_read_time(rtc, &tm);
+	if (err)
+		return err;
+	now = rtc_tm_to_time64(&tm);
+
+	if (scheduled <= now)
+		return -ETIME;
+	/*
+	 * XXX - We just checked to make sure the alarm time is not
+	 * in the past, but there is still a race window where if
+	 * the is alarm set for the next second and the second ticks
+	 * over right here, before we set the alarm.
+	 */
+
+	rtc_subtract_offset(rtc, &alarm->time);
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
+
+	trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
+	return err;
+}
+
+int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	ktime_t alarm_time;
+	int err;
+
+	if (!rtc->ops)
+		return -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
+		return -EINVAL;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err != 0)
+		return err;
+
+	err = rtc_valid_range(rtc, &alarm->time);
+	if (err)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+	if (rtc->aie_timer.enabled)
+		rtc_timer_remove(rtc, &rtc->aie_timer);
+
+	alarm_time = rtc_tm_to_ktime(alarm->time);
+	/*
+	 * Round down so we never miss a deadline, checking for past deadline is
+	 * done in __rtc_set_alarm
+	 */
+	if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
+		alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
+
+	rtc->aie_timer.node.expires = alarm_time;
+	rtc->aie_timer.period = 0;
+	if (alarm->enabled)
+		err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
+
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_alarm);
+
+/* Called once per device from rtc_device_register */
+int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_time now;
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err != 0)
+		return err;
+
+	err = rtc_read_time(rtc, &now);
+	if (err)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
+	rtc->aie_timer.period = 0;
+
+	/* Alarm has to be enabled & in the future for us to enqueue it */
+	if (alarm->enabled && (rtc_tm_to_ktime(now) <
+			 rtc->aie_timer.node.expires)) {
+		rtc->aie_timer.enabled = 1;
+		timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
+		trace_rtc_timer_enqueue(&rtc->aie_timer);
+	}
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
+
+int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+	if (rtc->aie_timer.enabled != enabled) {
+		if (enabled)
+			err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
+		else
+			rtc_timer_remove(rtc, &rtc->aie_timer);
+	}
+
+	if (err)
+		/* nothing */;
+	else if (!rtc->ops)
+		err = -ENODEV;
+	else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
+		err = -EINVAL;
+	else
+		err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
+
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_alarm_irq_enable(enabled, err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
+
+int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return err;
+
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+	if (enabled == 0 && rtc->uie_irq_active) {
+		mutex_unlock(&rtc->ops_lock);
+		return rtc_dev_update_irq_enable_emul(rtc, 0);
+	}
+#endif
+	/* make sure we're changing state */
+	if (rtc->uie_rtctimer.enabled == enabled)
+		goto out;
+
+	if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) ||
+	    !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
+		mutex_unlock(&rtc->ops_lock);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+		return rtc_dev_update_irq_enable_emul(rtc, enabled);
+#else
+		return -EINVAL;
+#endif
+	}
+
+	if (enabled) {
+		struct rtc_time tm;
+		ktime_t now, onesec;
+
+		err = __rtc_read_time(rtc, &tm);
+		if (err)
+			goto out;
+		onesec = ktime_set(1, 0);
+		now = rtc_tm_to_ktime(tm);
+		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
+		rtc->uie_rtctimer.period = ktime_set(1, 0);
+		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
+	} else {
+		rtc_timer_remove(rtc, &rtc->uie_rtctimer);
+	}
+
+out:
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
+
+/**
+ * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
+ * @rtc: pointer to the rtc device
+ * @num: number of occurence of the event
+ * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
+ *
+ * This function is called when an AIE, UIE or PIE mode interrupt
+ * has occurred (or been emulated).
+ *
+ */
+void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
+{
+	unsigned long flags;
+
+	/* mark one irq of the appropriate mode */
+	spin_lock_irqsave(&rtc->irq_lock, flags);
+	rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
+	spin_unlock_irqrestore(&rtc->irq_lock, flags);
+
+	wake_up_interruptible(&rtc->irq_queue);
+	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
+}
+
+/**
+ * rtc_aie_update_irq - AIE mode rtctimer hook
+ * @rtc: pointer to the rtc_device
+ *
+ * This functions is called when the aie_timer expires.
+ */
+void rtc_aie_update_irq(struct rtc_device *rtc)
+{
+	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
+}
+
+/**
+ * rtc_uie_update_irq - UIE mode rtctimer hook
+ * @rtc: pointer to the rtc_device
+ *
+ * This functions is called when the uie_timer expires.
+ */
+void rtc_uie_update_irq(struct rtc_device *rtc)
+{
+	rtc_handle_legacy_irq(rtc, 1,  RTC_UF);
+}
+
+/**
+ * rtc_pie_update_irq - PIE mode hrtimer hook
+ * @timer: pointer to the pie mode hrtimer
+ *
+ * This function is used to emulate PIE mode interrupts
+ * using an hrtimer. This function is called when the periodic
+ * hrtimer expires.
+ */
+enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
+{
+	struct rtc_device *rtc;
+	ktime_t period;
+	u64 count;
+
+	rtc = container_of(timer, struct rtc_device, pie_timer);
+
+	period = NSEC_PER_SEC / rtc->irq_freq;
+	count = hrtimer_forward_now(timer, period);
+
+	rtc_handle_legacy_irq(rtc, count, RTC_PF);
+
+	return HRTIMER_RESTART;
+}
+
+/**
+ * rtc_update_irq - Triggered when a RTC interrupt occurs.
+ * @rtc: the rtc device
+ * @num: how many irqs are being reported (usually one)
+ * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
+ * Context: any
+ */
+void rtc_update_irq(struct rtc_device *rtc,
+		    unsigned long num, unsigned long events)
+{
+	if (IS_ERR_OR_NULL(rtc))
+		return;
+
+	pm_stay_awake(rtc->dev.parent);
+	schedule_work(&rtc->irqwork);
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq);
+
+struct rtc_device *rtc_class_open(const char *name)
+{
+	struct device *dev;
+	struct rtc_device *rtc = NULL;
+
+	dev = class_find_device_by_name(rtc_class, name);
+	if (dev)
+		rtc = to_rtc_device(dev);
+
+	if (rtc) {
+		if (!try_module_get(rtc->owner)) {
+			put_device(dev);
+			rtc = NULL;
+		}
+	}
+
+	return rtc;
+}
+EXPORT_SYMBOL_GPL(rtc_class_open);
+
+void rtc_class_close(struct rtc_device *rtc)
+{
+	module_put(rtc->owner);
+	put_device(&rtc->dev);
+}
+EXPORT_SYMBOL_GPL(rtc_class_close);
+
+static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
+{
+	/*
+	 * We always cancel the timer here first, because otherwise
+	 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
+	 * when we manage to start the timer before the callback
+	 * returns HRTIMER_RESTART.
+	 *
+	 * We cannot use hrtimer_cancel() here as a running callback
+	 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
+	 * would spin forever.
+	 */
+	if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
+		return -1;
+
+	if (enabled) {
+		ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
+
+		hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
+	}
+	return 0;
+}
+
+/**
+ * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
+ * @rtc: the rtc device
+ * @enabled: true to enable periodic IRQs
+ * Context: any
+ *
+ * Note that rtc_irq_set_freq() should previously have been used to
+ * specify the desired frequency of periodic IRQ.
+ */
+int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
+{
+	int err = 0;
+
+	while (rtc_update_hrtimer(rtc, enabled) < 0)
+		cpu_relax();
+
+	rtc->pie_enabled = enabled;
+
+	trace_rtc_irq_set_state(enabled, err);
+	return err;
+}
+
+/**
+ * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
+ * @rtc: the rtc device
+ * @freq: positive frequency
+ * Context: any
+ *
+ * Note that rtc_irq_set_state() is used to enable or disable the
+ * periodic IRQs.
+ */
+int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
+{
+	int err = 0;
+
+	if (freq <= 0 || freq > RTC_MAX_FREQ)
+		return -EINVAL;
+
+	rtc->irq_freq = freq;
+	while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
+		cpu_relax();
+
+	trace_rtc_irq_set_freq(freq, err);
+	return err;
+}
+
+/**
+ * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
+ * @rtc: rtc device
+ * @timer: timer being added.
+ *
+ * Enqueues a timer onto the rtc devices timerqueue and sets
+ * the next alarm event appropriately.
+ *
+ * Sets the enabled bit on the added timer.
+ *
+ * Must hold ops_lock for proper serialization of timerqueue
+ */
+static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
+	struct rtc_time tm;
+	ktime_t now;
+	int err;
+
+	err = __rtc_read_time(rtc, &tm);
+	if (err)
+		return err;
+
+	timer->enabled = 1;
+	now = rtc_tm_to_ktime(tm);
+
+	/* Skip over expired timers */
+	while (next) {
+		if (next->expires >= now)
+			break;
+		next = timerqueue_iterate_next(next);
+	}
+
+	timerqueue_add(&rtc->timerqueue, &timer->node);
+	trace_rtc_timer_enqueue(timer);
+	if (!next || ktime_before(timer->node.expires, next->expires)) {
+		struct rtc_wkalrm alarm;
+
+		alarm.time = rtc_ktime_to_tm(timer->node.expires);
+		alarm.enabled = 1;
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			pm_stay_awake(rtc->dev.parent);
+			schedule_work(&rtc->irqwork);
+		} else if (err) {
+			timerqueue_del(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_dequeue(timer);
+			timer->enabled = 0;
+			return err;
+		}
+	}
+	return 0;
+}
+
+static void rtc_alarm_disable(struct rtc_device *rtc)
+{
+	if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
+		return;
+
+	rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
+	trace_rtc_alarm_irq_enable(0, 0);
+}
+
+/**
+ * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
+ * @rtc: rtc device
+ * @timer: timer being removed.
+ *
+ * Removes a timer onto the rtc devices timerqueue and sets
+ * the next alarm event appropriately.
+ *
+ * Clears the enabled bit on the removed timer.
+ *
+ * Must hold ops_lock for proper serialization of timerqueue
+ */
+static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
+
+	timerqueue_del(&rtc->timerqueue, &timer->node);
+	trace_rtc_timer_dequeue(timer);
+	timer->enabled = 0;
+	if (next == &timer->node) {
+		struct rtc_wkalrm alarm;
+		int err;
+
+		next = timerqueue_getnext(&rtc->timerqueue);
+		if (!next) {
+			rtc_alarm_disable(rtc);
+			return;
+		}
+		alarm.time = rtc_ktime_to_tm(next->expires);
+		alarm.enabled = 1;
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			pm_stay_awake(rtc->dev.parent);
+			schedule_work(&rtc->irqwork);
+		}
+	}
+}
+
+/**
+ * rtc_timer_do_work - Expires rtc timers
+ * @work: work item
+ *
+ * Expires rtc timers. Reprograms next alarm event if needed.
+ * Called via worktask.
+ *
+ * Serializes access to timerqueue via ops_lock mutex
+ */
+void rtc_timer_do_work(struct work_struct *work)
+{
+	struct rtc_timer *timer;
+	struct timerqueue_node *next;
+	ktime_t now;
+	struct rtc_time tm;
+
+	struct rtc_device *rtc =
+		container_of(work, struct rtc_device, irqwork);
+
+	mutex_lock(&rtc->ops_lock);
+again:
+	__rtc_read_time(rtc, &tm);
+	now = rtc_tm_to_ktime(tm);
+	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
+		if (next->expires > now)
+			break;
+
+		/* expire timer */
+		timer = container_of(next, struct rtc_timer, node);
+		timerqueue_del(&rtc->timerqueue, &timer->node);
+		trace_rtc_timer_dequeue(timer);
+		timer->enabled = 0;
+		if (timer->func)
+			timer->func(timer->rtc);
+
+		trace_rtc_timer_fired(timer);
+		/* Re-add/fwd periodic timers */
+		if (ktime_to_ns(timer->period)) {
+			timer->node.expires = ktime_add(timer->node.expires,
+							timer->period);
+			timer->enabled = 1;
+			timerqueue_add(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_enqueue(timer);
+		}
+	}
+
+	/* Set next alarm */
+	if (next) {
+		struct rtc_wkalrm alarm;
+		int err;
+		int retry = 3;
+
+		alarm.time = rtc_ktime_to_tm(next->expires);
+		alarm.enabled = 1;
+reprogram:
+		err = __rtc_set_alarm(rtc, &alarm);
+		if (err == -ETIME) {
+			goto again;
+		} else if (err) {
+			if (retry-- > 0)
+				goto reprogram;
+
+			timer = container_of(next, struct rtc_timer, node);
+			timerqueue_del(&rtc->timerqueue, &timer->node);
+			trace_rtc_timer_dequeue(timer);
+			timer->enabled = 0;
+			dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
+			goto again;
+		}
+	} else {
+		rtc_alarm_disable(rtc);
+	}
+
+	pm_relax(rtc->dev.parent);
+	mutex_unlock(&rtc->ops_lock);
+}
+
+/* rtc_timer_init - Initializes an rtc_timer
+ * @timer: timer to be intiialized
+ * @f: function pointer to be called when timer fires
+ * @rtc: pointer to the rtc_device
+ *
+ * Kernel interface to initializing an rtc_timer.
+ */
+void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
+		    struct rtc_device *rtc)
+{
+	timerqueue_init(&timer->node);
+	timer->enabled = 0;
+	timer->func = f;
+	timer->rtc = rtc;
+}
+
+/* rtc_timer_start - Sets an rtc_timer to fire in the future
+ * @ rtc: rtc device to be used
+ * @ timer: timer being set
+ * @ expires: time at which to expire the timer
+ * @ period: period that the timer will recur
+ *
+ * Kernel interface to set an rtc_timer
+ */
+int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
+		    ktime_t expires, ktime_t period)
+{
+	int ret = 0;
+
+	mutex_lock(&rtc->ops_lock);
+	if (timer->enabled)
+		rtc_timer_remove(rtc, timer);
+
+	timer->node.expires = expires;
+	timer->period = period;
+
+	ret = rtc_timer_enqueue(rtc, timer);
+
+	mutex_unlock(&rtc->ops_lock);
+	return ret;
+}
+
+/* rtc_timer_cancel - Stops an rtc_timer
+ * @ rtc: rtc device to be used
+ * @ timer: timer being set
+ *
+ * Kernel interface to cancel an rtc_timer
+ */
+void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
+{
+	mutex_lock(&rtc->ops_lock);
+	if (timer->enabled)
+		rtc_timer_remove(rtc, timer);
+	mutex_unlock(&rtc->ops_lock);
+}
+
+/**
+ * rtc_read_offset - Read the amount of rtc offset in parts per billion
+ * @rtc: rtc device to be used
+ * @offset: the offset in parts per billion
+ *
+ * see below for details.
+ *
+ * Kernel interface to read rtc clock offset
+ * Returns 0 on success, or a negative number on error.
+ * If read_offset() is not implemented for the rtc, return -EINVAL
+ */
+int rtc_read_offset(struct rtc_device *rtc, long *offset)
+{
+	int ret;
+
+	if (!rtc->ops)
+		return -ENODEV;
+
+	if (!rtc->ops->read_offset)
+		return -EINVAL;
+
+	mutex_lock(&rtc->ops_lock);
+	ret = rtc->ops->read_offset(rtc->dev.parent, offset);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_read_offset(*offset, ret);
+	return ret;
+}
+
+/**
+ * rtc_set_offset - Adjusts the duration of the average second
+ * @rtc: rtc device to be used
+ * @offset: the offset in parts per billion
+ *
+ * Some rtc's allow an adjustment to the average duration of a second
+ * to compensate for differences in the actual clock rate due to temperature,
+ * the crystal, capacitor, etc.
+ *
+ * The adjustment applied is as follows:
+ *   t = t0 * (1 + offset * 1e-9)
+ * where t0 is the measured length of 1 RTC second with offset = 0
+ *
+ * Kernel interface to adjust an rtc clock offset.
+ * Return 0 on success, or a negative number on error.
+ * If the rtc offset is not setable (or not implemented), return -EINVAL
+ */
+int rtc_set_offset(struct rtc_device *rtc, long offset)
+{
+	int ret;
+
+	if (!rtc->ops)
+		return -ENODEV;
+
+	if (!rtc->ops->set_offset)
+		return -EINVAL;
+
+	mutex_lock(&rtc->ops_lock);
+	ret = rtc->ops->set_offset(rtc->dev.parent, offset);
+	mutex_unlock(&rtc->ops_lock);
+
+	trace_rtc_set_offset(offset, ret);
+	return ret;
+}