1 files changed, 382 insertions, 0 deletions
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
new file mode 100644
index 000000000..ea2a315df
--- /dev/null
+++ b/drivers/rtc/class.c
@@ -0,0 +1,382 @@
+/*
+ * RTC subsystem, base class
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * class skeleton from drivers/hwmon/hwmon.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/rtc.h>
+#include <linux/kdev_t.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "rtc-core.h"
+
+
+static DEFINE_IDA(rtc_ida);
+struct class *rtc_class;
+
+static void rtc_device_release(struct device *dev)
+{
+	struct rtc_device *rtc = to_rtc_device(dev);
+	ida_simple_remove(&rtc_ida, rtc->id);
+	kfree(rtc);
+}
+
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+/* Result of the last RTC to system clock attempt. */
+int rtc_hctosys_ret = -ENODEV;
+#endif
+
+#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
+/*
+ * On suspend(), measure the delta between one RTC and the
+ * system's wall clock; restore it on resume().
+ */
+
+static struct timespec64 old_rtc, old_system, old_delta;
+
+
+static int rtc_suspend(struct device *dev)
+{
+	struct rtc_device	*rtc = to_rtc_device(dev);
+	struct rtc_time		tm;
+	struct timespec64	delta, delta_delta;
+	int err;
+
+	if (timekeeping_rtc_skipsuspend())
+		return 0;
+
+	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
+		return 0;
+
+	/* snapshot the current RTC and system time at suspend*/
+	err = rtc_read_time(rtc, &tm);
+	if (err < 0) {
+		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
+		return 0;
+	}
+
+	getnstimeofday64(&old_system);
+	old_rtc.tv_sec = rtc_tm_to_time64(&tm);
+
+
+	/*
+	 * To avoid drift caused by repeated suspend/resumes,
+	 * which each can add ~1 second drift error,
+	 * try to compensate so the difference in system time
+	 * and rtc time stays close to constant.
+	 */
+	delta = timespec64_sub(old_system, old_rtc);
+	delta_delta = timespec64_sub(delta, old_delta);
+	if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
+		/*
+		 * if delta_delta is too large, assume time correction
+		 * has occured and set old_delta to the current delta.
+		 */
+		old_delta = delta;
+	} else {
+		/* Otherwise try to adjust old_system to compensate */
+		old_system = timespec64_sub(old_system, delta_delta);
+	}
+
+	return 0;
+}
+
+static int rtc_resume(struct device *dev)
+{
+	struct rtc_device	*rtc = to_rtc_device(dev);
+	struct rtc_time		tm;
+	struct timespec64	new_system, new_rtc;
+	struct timespec64	sleep_time;
+	int err;
+
+	if (timekeeping_rtc_skipresume())
+		return 0;
+
+	rtc_hctosys_ret = -ENODEV;
+	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
+		return 0;
+
+	/* snapshot the current rtc and system time at resume */
+	getnstimeofday64(&new_system);
+	err = rtc_read_time(rtc, &tm);
+	if (err < 0) {
+		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
+		return 0;
+	}
+
+	new_rtc.tv_sec = rtc_tm_to_time64(&tm);
+	new_rtc.tv_nsec = 0;
+
+	if (new_rtc.tv_sec < old_rtc.tv_sec) {
+		pr_debug("%s:  time travel!\n", dev_name(&rtc->dev));
+		return 0;
+	}
+
+	/* calculate the RTC time delta (sleep time)*/
+	sleep_time = timespec64_sub(new_rtc, old_rtc);
+
+	/*
+	 * Since these RTC suspend/resume handlers are not called
+	 * at the very end of suspend or the start of resume,
+	 * some run-time may pass on either sides of the sleep time
+	 * so subtract kernel run-time between rtc_suspend to rtc_resume
+	 * to keep things accurate.
+	 */
+	sleep_time = timespec64_sub(sleep_time,
+			timespec64_sub(new_system, old_system));
+
+	if (sleep_time.tv_sec >= 0)
+		timekeeping_inject_sleeptime64(&sleep_time);
+	rtc_hctosys_ret = 0;
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
+#define RTC_CLASS_DEV_PM_OPS	(&rtc_class_dev_pm_ops)
+#else
+#define RTC_CLASS_DEV_PM_OPS	NULL
+#endif
+
+
+/**
+ * rtc_device_register - register w/ RTC class
+ * @dev: the device to register
+ *
+ * rtc_device_unregister() must be called when the class device is no
+ * longer needed.
+ *
+ * Returns the pointer to the new struct class device.
+ */
+struct rtc_device *rtc_device_register(const char *name, struct device *dev,
+					const struct rtc_class_ops *ops,
+					struct module *owner)
+{
+	struct rtc_device *rtc;
+	struct rtc_wkalrm alrm;
+	int of_id = -1, id = -1, err;
+
+	if (dev->of_node)
+		of_id = of_alias_get_id(dev->of_node, "rtc");
+	else if (dev->parent && dev->parent->of_node)
+		of_id = of_alias_get_id(dev->parent->of_node, "rtc");
+
+	if (of_id >= 0) {
+		id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
+				    GFP_KERNEL);
+		if (id < 0)
+			dev_warn(dev, "/aliases ID %d not available\n",
+				    of_id);
+	}
+
+	if (id < 0) {
+		id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
+		if (id < 0) {
+			err = id;
+			goto exit;
+		}
+	}
+
+	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
+	if (rtc == NULL) {
+		err = -ENOMEM;
+		goto exit_ida;
+	}
+
+	rtc->id = id;
+	rtc->ops = ops;
+	rtc->owner = owner;
+	rtc->irq_freq = 1;
+	rtc->max_user_freq = 64;
+	rtc->dev.parent = dev;
+	rtc->dev.class = rtc_class;
+	rtc->dev.release = rtc_device_release;
+
+	mutex_init(&rtc->ops_lock);
+	spin_lock_init(&rtc->irq_lock);
+	spin_lock_init(&rtc->irq_task_lock);
+	init_waitqueue_head(&rtc->irq_queue);
+
+	/* Init timerqueue */
+	timerqueue_init_head(&rtc->timerqueue);
+	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
+	/* Init aie timer */
+	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
+	/* Init uie timer */
+	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
+	/* Init pie timer */
+	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	rtc->pie_timer.function = rtc_pie_update_irq;
+	rtc->pie_enabled = 0;
+
+	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
+	dev_set_name(&rtc->dev, "rtc%d", id);
+
+	/* 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 = device_register(&rtc->dev);
+	if (err) {
+		put_device(&rtc->dev);
+		goto exit_kfree;
+	}
+
+	rtc_dev_add_device(rtc);
+	rtc_sysfs_add_device(rtc);
+	rtc_proc_add_device(rtc);
+
+	dev_info(dev, "rtc core: registered %s as %s\n",
+			rtc->name, dev_name(&rtc->dev));
+
+	return rtc;
+
+exit_kfree:
+	kfree(rtc);
+
+exit_ida:
+	ida_simple_remove(&rtc_ida, id);
+
+exit:
+	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
+			name, err);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(rtc_device_register);
+
+
+/**
+ * rtc_device_unregister - removes the previously registered RTC class device
+ *
+ * @rtc: the RTC class device to destroy
+ */
+void rtc_device_unregister(struct rtc_device *rtc)
+{
+	if (get_device(&rtc->dev) != NULL) {
+		mutex_lock(&rtc->ops_lock);
+		/* remove innards of this RTC, then disable it, before
+		 * letting any rtc_class_open() users access it again
+		 */
+		rtc_sysfs_del_device(rtc);
+		rtc_dev_del_device(rtc);
+		rtc_proc_del_device(rtc);
+		device_unregister(&rtc->dev);
+		rtc->ops = NULL;
+		mutex_unlock(&rtc->ops_lock);
+		put_device(&rtc->dev);
+	}
+}
+EXPORT_SYMBOL_GPL(rtc_device_unregister);
+
+static void devm_rtc_device_release(struct device *dev, void *res)
+{
+	struct rtc_device *rtc = *(struct rtc_device **)res;
+
+	rtc_device_unregister(rtc);
+}
+
+static int devm_rtc_device_match(struct device *dev, void *res, void *data)
+{
+	struct rtc **r = res;
+
+	return *r == data;
+}
+
+/**
+ * devm_rtc_device_register - resource managed rtc_device_register()
+ * @dev: the device to register
+ * @name: the name of the device
+ * @ops: the rtc operations structure
+ * @owner: the module owner
+ *
+ * @return a struct rtc on success, or an ERR_PTR on error
+ *
+ * Managed rtc_device_register(). The rtc_device returned from this function
+ * are automatically freed on driver detach. See rtc_device_register()
+ * for more information.
+ */
+
+struct rtc_device *devm_rtc_device_register(struct device *dev,
+					const char *name,
+					const struct rtc_class_ops *ops,
+					struct module *owner)
+{
+	struct rtc_device **ptr, *rtc;
+
+	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	rtc = rtc_device_register(name, dev, ops, owner);
+	if (!IS_ERR(rtc)) {
+		*ptr = rtc;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return rtc;
+}
+EXPORT_SYMBOL_GPL(devm_rtc_device_register);
+
+/**
+ * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
+ * @dev: the device to unregister
+ * @rtc: the RTC class device to unregister
+ *
+ * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
+ * function will not need to be called and the resource management code will
+ * ensure that the resource is freed.
+ */
+void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
+{
+	int rc;
+
+	rc = devres_release(dev, devm_rtc_device_release,
+				devm_rtc_device_match, rtc);
+	WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
+
+static int __init rtc_init(void)
+{
+	rtc_class = class_create(THIS_MODULE, "rtc");
+	if (IS_ERR(rtc_class)) {
+		pr_err("couldn't create class\n");
+		return PTR_ERR(rtc_class);
+	}
+	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
+	rtc_dev_init();
+	rtc_sysfs_init(rtc_class);
+	return 0;
+}
+
+static void __exit rtc_exit(void)
+{
+	rtc_dev_exit();
+	class_destroy(rtc_class);
+	ida_destroy(&rtc_ida);
+}
+
+subsys_initcall(rtc_init);
+module_exit(rtc_exit);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("RTC class support");
+MODULE_LICENSE("GPL");