diff --git a/upstream/linux-5.10/drivers/rtc/class.c b/upstream/linux-5.10/drivers/rtc/class.c
new file mode 100755
index 0000000..625effe
--- /dev/null
+++ b/upstream/linux-5.10/drivers/rtc/class.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC subsystem, base class
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * class skeleton from drivers/hwmon/hwmon.c
+ */
+
+#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);
+	struct timerqueue_head *head = &rtc->timerqueue;
+	struct timerqueue_node *node;
+
+	mutex_lock(&rtc->ops_lock);
+	while ((node = timerqueue_getnext(head)))
+		timerqueue_del(head, node);
+	mutex_unlock(&rtc->ops_lock);
+
+	cancel_work_sync(&rtc->irqwork);
+
+	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;
+
+/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+ * whether it stores the most close value or the value with partial
+ * seconds truncated. However, it is important that we use it to store
+ * the truncated value. This is because otherwise it is necessary,
+ * in an rtc sync function, to read both xtime.tv_sec and
+ * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+ * of >32bits is not possible. So storing the most close value would
+ * slow down the sync API. So here we have the truncated value and
+ * the best guess is to add 0.5s.
+ */
+
+static void rtc_hctosys(struct rtc_device *rtc)
+{
+	int err;
+	struct rtc_time tm;
+	struct timespec64 tv64 = {
+		.tv_nsec = NSEC_PER_SEC >> 1,
+	};
+
+	err = rtc_read_time(rtc, &tm);
+	if (err) {
+		dev_err(rtc->dev.parent,
+			"hctosys: unable to read the hardware clock\n");
+		goto err_read;
+	}
+
+	tv64.tv_sec = rtc_tm_to_time64(&tm);
+
+#if BITS_PER_LONG == 32
+	if (tv64.tv_sec > INT_MAX) {
+		err = -ERANGE;
+		goto err_read;
+	}
+#endif
+
+	err = do_settimeofday64(&tv64);
+
+	dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
+		 &tm, (long long)tv64.tv_sec);
+
+err_read:
+	rtc_hctosys_ret = err;
+}
+#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;
+	}
+
+	ktime_get_real_ts64(&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 occurred 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 */
+	ktime_get_real_ts64(&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
+
+/* Ensure the caller will set the id before releasing the device */
+static struct rtc_device *rtc_allocate_device(void)
+{
+	struct rtc_device *rtc;
+
+	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return NULL;
+
+	device_initialize(&rtc->dev);
+
+	/* Drivers can revise this default after allocating the device. */
+	rtc->set_offset_nsec =  NSEC_PER_SEC / 2;
+
+	rtc->irq_freq = 1;
+	rtc->max_user_freq = 64;
+	rtc->dev.class = rtc_class;
+	rtc->dev.groups = rtc_get_dev_attribute_groups();
+	rtc->dev.release = rtc_device_release;
+
+	mutex_init(&rtc->ops_lock);
+	spin_lock_init(&rtc->irq_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, rtc);
+	/* Init uie timer */
+	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, 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;
+
+	return rtc;
+}
+
+static int rtc_device_get_id(struct device *dev)
+{
+	int of_id = -1, id = -1;
+
+	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);
+
+	return id;
+}
+
+static void rtc_device_get_offset(struct rtc_device *rtc)
+{
+	time64_t range_secs;
+	u32 start_year;
+	int ret;
+
+	/*
+	 * If RTC driver did not implement the range of RTC hardware device,
+	 * then we can not expand the RTC range by adding or subtracting one
+	 * offset.
+	 */
+	if (rtc->range_min == rtc->range_max)
+		return;
+
+	ret = device_property_read_u32(rtc->dev.parent, "start-year",
+				       &start_year);
+	if (!ret) {
+		rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
+		rtc->set_start_time = true;
+	}
+
+	/*
+	 * If user did not implement the start time for RTC driver, then no
+	 * need to expand the RTC range.
+	 */
+	if (!rtc->set_start_time)
+		return;
+
+	range_secs = rtc->range_max - rtc->range_min + 1;
+
+	/*
+	 * If the start_secs is larger than the maximum seconds (rtc->range_max)
+	 * supported by RTC hardware or the maximum seconds of new expanded
+	 * range (start_secs + rtc->range_max - rtc->range_min) is less than
+	 * rtc->range_min, which means the minimum seconds (rtc->range_min) of
+	 * RTC hardware will be mapped to start_secs by adding one offset, so
+	 * the offset seconds calculation formula should be:
+	 * rtc->offset_secs = rtc->start_secs - rtc->range_min;
+	 *
+	 * If the start_secs is larger than the minimum seconds (rtc->range_min)
+	 * supported by RTC hardware, then there is one region is overlapped
+	 * between the original RTC hardware range and the new expanded range,
+	 * and this overlapped region do not need to be mapped into the new
+	 * expanded range due to it is valid for RTC device. So the minimum
+	 * seconds of RTC hardware (rtc->range_min) should be mapped to
+	 * rtc->range_max + 1, then the offset seconds formula should be:
+	 * rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
+	 *
+	 * If the start_secs is less than the minimum seconds (rtc->range_min),
+	 * which is similar to case 2. So the start_secs should be mapped to
+	 * start_secs + rtc->range_max - rtc->range_min + 1, then the
+	 * offset seconds formula should be:
+	 * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
+	 *
+	 * Otherwise the offset seconds should be 0.
+	 */
+	if (rtc->start_secs > rtc->range_max ||
+	    rtc->start_secs + range_secs - 1 < rtc->range_min)
+		rtc->offset_secs = rtc->start_secs - rtc->range_min;
+	else if (rtc->start_secs > rtc->range_min)
+		rtc->offset_secs = range_secs;
+	else if (rtc->start_secs < rtc->range_min)
+		rtc->offset_secs = -range_secs;
+	else
+		rtc->offset_secs = 0;
+}
+
+/**
+ * rtc_device_unregister - removes the previously registered RTC class device
+ *
+ * @rtc: the RTC class device to destroy
+ */
+static void rtc_device_unregister(struct rtc_device *rtc)
+{
+	mutex_lock(&rtc->ops_lock);
+	/*
+	 * Remove innards of this RTC, then disable it, before
+	 * letting any rtc_class_open() users access it again
+	 */
+	rtc_proc_del_device(rtc);
+	cdev_device_del(&rtc->char_dev, &rtc->dev);
+	rtc->ops = NULL;
+	mutex_unlock(&rtc->ops_lock);
+	put_device(&rtc->dev);
+}
+
+static void devm_rtc_release_device(struct device *dev, void *res)
+{
+	struct rtc_device *rtc = *(struct rtc_device **)res;
+
+	rtc_nvmem_unregister(rtc);
+
+	if (rtc->registered)
+		rtc_device_unregister(rtc);
+	else
+		put_device(&rtc->dev);
+}
+
+struct rtc_device *devm_rtc_allocate_device(struct device *dev)
+{
+	struct rtc_device **ptr, *rtc;
+	int id, err;
+
+	id = rtc_device_get_id(dev);
+	if (id < 0)
+		return ERR_PTR(id);
+
+	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr) {
+		err = -ENOMEM;
+		goto exit_ida;
+	}
+
+	rtc = rtc_allocate_device();
+	if (!rtc) {
+		err = -ENOMEM;
+		goto exit_devres;
+	}
+
+	*ptr = rtc;
+	devres_add(dev, ptr);
+
+	rtc->id = id;
+	rtc->dev.parent = dev;
+	dev_set_name(&rtc->dev, "rtc%d", id);
+
+	return rtc;
+
+exit_devres:
+	devres_free(ptr);
+exit_ida:
+	ida_simple_remove(&rtc_ida, id);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
+
+int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
+{
+	struct rtc_wkalrm alrm;
+	int err;
+
+	if (!rtc->ops) {
+		dev_dbg(&rtc->dev, "no ops set\n");
+		return -EINVAL;
+	}
+
+	rtc->owner = owner;
+	rtc_device_get_offset(rtc);
+
+	/* 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);
+
+	rtc_dev_prepare(rtc);
+
+	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
+	if (err)
+		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
+			 MAJOR(rtc->dev.devt), rtc->id);
+	else
+		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
+			MAJOR(rtc->dev.devt), rtc->id);
+
+	rtc_proc_add_device(rtc);
+
+	rtc->registered = true;
+	dev_info(rtc->dev.parent, "registered as %s\n",
+		 dev_name(&rtc->dev));
+
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+	if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE))
+		rtc_hctosys(rtc);
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__rtc_register_device);
+
+/**
+ * devm_rtc_device_register - resource managed rtc_device_register()
+ * @dev: the device to register
+ * @name: the name of the device (unused)
+ * @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.
+ * This function is deprecated, use devm_rtc_allocate_device and
+ * rtc_register_device instead
+ */
+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 *rtc;
+	int err;
+
+	rtc = devm_rtc_allocate_device(dev);
+	if (IS_ERR(rtc))
+		return rtc;
+
+	rtc->ops = ops;
+
+	err = __rtc_register_device(owner, rtc);
+	if (err)
+		return ERR_PTR(err);
+
+	return rtc;
+}
+EXPORT_SYMBOL_GPL(devm_rtc_device_register);
+
+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();
+	return 0;
+}
+subsys_initcall(rtc_init);