From: Arve Hjønnevåg <arve@android.com>
Date: Wed, 15 Oct 2008 00:38:04 +0000 (-0700)
Subject: rtc: Add android alarm driver.
X-Git-Tag: firefly_0821_release~9833^2~5^2~333
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e5642795c4c75493a255f27646d784cd70f4ef70;p=firefly-linux-kernel-4.4.55.git

rtc: Add android alarm driver.
---

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 48ca7132cc05..ae2e0c3384d4 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -109,6 +109,16 @@ config RTC_INTF_DEV_UIE_EMUL
 	  clock several times per second, please enable this option
 	  only if you know that you really need it.
 
+config RTC_INTF_ALARM
+	bool "Android alarm driver"
+	depends on RTC_CLASS
+	default y
+	help
+	  Provides non-wakeup and rtc backed wakeup alarms based on rtc or
+	  elapsed realtime, and a non-wakeup alarm on the monotonic clock.
+	  Also provides an ioctl to set the wall time which must be used
+	  for elapsed realtime to work.
+
 config RTC_DRV_TEST
 	tristate "Test driver/device"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0f207b3b5833..36ffc1cdc20f 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_RTC_HCTOSYS)	+= hctosys.o
 obj-$(CONFIG_RTC_CLASS)		+= rtc-core.o
 rtc-core-y			:= class.o interface.o
 
+rtc-core-$(CONFIG_RTC_INTF_ALARM) += alarm.o
 rtc-core-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o
 rtc-core-$(CONFIG_RTC_INTF_PROC) += rtc-proc.o
 rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
diff --git a/drivers/rtc/alarm.c b/drivers/rtc/alarm.c
new file mode 100644
index 000000000000..cd660eee3b27
--- /dev/null
+++ b/drivers/rtc/alarm.c
@@ -0,0 +1,568 @@
+/* drivers/rtc/alarm.c
+ *
+ * Copyright (C) 2007 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <asm/mach/time.h>
+#include <linux/android_alarm.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/sysdev.h>
+#include <linux/wakelock.h>
+
+#define ANDROID_ALARM_PRINT_ERRORS (1U << 0)
+#define ANDROID_ALARM_PRINT_INIT_STATUS (1U << 1)
+#define ANDROID_ALARM_PRINT_INFO (1U << 2)
+#define ANDROID_ALARM_PRINT_IO (1U << 3)
+#define ANDROID_ALARM_PRINT_INT (1U << 4)
+#define ANDROID_ALARM_PRINT_FLOW (1U << 5)
+
+#if 0
+#define ANDROID_ALARM_DPRINTF_MASK (~0)
+#define ANDROID_ALARM_DPRINTF(debug_level_mask, args...) \
+	do { \
+		if (ANDROID_ALARM_DPRINTF_MASK & debug_level_mask) { \
+			printk(args); \
+		} \
+	} while (0)
+#else
+#define ANDROID_ALARM_DPRINTF(args...)
+#endif
+
+#define ANDROID_ALARM_WAKEUP_MASK ( \
+	ANDROID_ALARM_RTC_WAKEUP_MASK | \
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK)
+
+/* support old usespace code */
+#define ANDROID_ALARM_SET_OLD               _IOW('a', 2, time_t) /* set alarm */
+#define ANDROID_ALARM_SET_AND_WAIT_OLD      _IOW('a', 3, time_t)
+
+static struct rtc_device *alarm_rtc_dev;
+static int alarm_opened;
+static DEFINE_SPINLOCK(alarm_slock);
+static DEFINE_MUTEX(alarm_setrtc_mutex);
+static struct wake_lock alarm_wake_lock;
+static struct wake_lock alarm_rtc_wake_lock;
+static DECLARE_WAIT_QUEUE_HEAD(alarm_wait_queue);
+static uint32_t alarm_pending;
+static uint32_t alarm_enabled;
+static uint32_t wait_pending;
+static struct platform_device *alarm_platform_dev;
+static struct hrtimer alarm_timer[ANDROID_ALARM_TYPE_COUNT];
+static struct timespec alarm_time[ANDROID_ALARM_TYPE_COUNT];
+static struct timespec elapsed_rtc_delta;
+
+static void alarm_start_hrtimer(enum android_alarm_type alarm_type)
+{
+	struct timespec hr_alarm_time;
+	if (!(alarm_enabled & (1U << alarm_type)))
+		return;
+	hr_alarm_time = alarm_time[alarm_type];
+	if (alarm_type == ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP ||
+	    alarm_type == ANDROID_ALARM_ELAPSED_REALTIME)
+		set_normalized_timespec(&hr_alarm_time,
+			hr_alarm_time.tv_sec + elapsed_rtc_delta.tv_sec,
+			hr_alarm_time.tv_nsec + elapsed_rtc_delta.tv_nsec);
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_FLOW,
+		"alarm start hrtimer %d at %ld.%09ld\n",
+		alarm_type, hr_alarm_time.tv_sec, hr_alarm_time.tv_nsec);
+	hrtimer_start(&alarm_timer[alarm_type],
+		      timespec_to_ktime(hr_alarm_time), HRTIMER_MODE_ABS);
+}
+
+static long alarm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int rv = 0;
+	unsigned long flags;
+	int i;
+	struct timespec new_alarm_time;
+	struct timespec new_rtc_time;
+	struct timespec tmp_time;
+	struct rtc_time rtc_new_rtc_time;
+	enum android_alarm_type alarm_type = ANDROID_ALARM_IOCTL_TO_TYPE(cmd);
+	uint32_t alarm_type_mask = 1U << alarm_type;
+
+	if (alarm_type >= ANDROID_ALARM_TYPE_COUNT)
+		return -EINVAL;
+
+	if (ANDROID_ALARM_BASE_CMD(cmd) != ANDROID_ALARM_GET_TIME(0)) {
+		if ((file->f_flags & O_ACCMODE) == O_RDONLY)
+			return -EPERM;
+		if (file->private_data == NULL &&
+		    cmd != ANDROID_ALARM_SET_RTC) {
+			spin_lock_irqsave(&alarm_slock, flags);
+			if (alarm_opened) {
+				spin_unlock_irqrestore(&alarm_slock, flags);
+				return -EBUSY;
+			}
+			alarm_opened = 1;
+			file->private_data = (void *)1;
+			spin_unlock_irqrestore(&alarm_slock, flags);
+		}
+	}
+
+	switch (ANDROID_ALARM_BASE_CMD(cmd)) {
+	case ANDROID_ALARM_CLEAR(0):
+		spin_lock_irqsave(&alarm_slock, flags);
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_IO,
+				      "alarm %d clear\n", alarm_type);
+		hrtimer_try_to_cancel(&alarm_timer[alarm_type]);
+		if (alarm_pending) {
+			alarm_pending &= ~alarm_type_mask;
+			if (!alarm_pending && !wait_pending)
+				wake_unlock(&alarm_wake_lock);
+		}
+		alarm_enabled &= ~alarm_type_mask;
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		break;
+
+	case ANDROID_ALARM_SET_OLD:
+	case ANDROID_ALARM_SET_AND_WAIT_OLD:
+		if (get_user(new_alarm_time.tv_sec, (int __user *)arg)) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		new_alarm_time.tv_nsec = 0;
+		goto from_old_alarm_set;
+
+	case ANDROID_ALARM_SET_AND_WAIT(0):
+	case ANDROID_ALARM_SET(0):
+		if (copy_from_user(&new_alarm_time, (void __user *)arg,
+		    sizeof(new_alarm_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+from_old_alarm_set:
+		spin_lock_irqsave(&alarm_slock, flags);
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_IO,
+			"alarm %d set %ld.%09ld\n", alarm_type,
+			new_alarm_time.tv_sec, new_alarm_time.tv_nsec);
+		alarm_time[alarm_type] = new_alarm_time;
+		alarm_enabled |= alarm_type_mask;
+		alarm_start_hrtimer(alarm_type);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		if (ANDROID_ALARM_BASE_CMD(cmd) != ANDROID_ALARM_SET_AND_WAIT(0)
+		    && cmd != ANDROID_ALARM_SET_AND_WAIT_OLD)
+			break;
+		/* fall though */
+	case ANDROID_ALARM_WAIT:
+		spin_lock_irqsave(&alarm_slock, flags);
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_IO, "alarm wait\n");
+		if (!alarm_pending && wait_pending) {
+			wake_unlock(&alarm_wake_lock);
+			wait_pending = 0;
+		}
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		rv = wait_event_interruptible(alarm_wait_queue, alarm_pending);
+		if (rv)
+			goto err1;
+		spin_lock_irqsave(&alarm_slock, flags);
+		rv = alarm_pending;
+		wait_pending = 1;
+		alarm_pending = 0;
+		if (rv & ANDROID_ALARM_WAKEUP_MASK)
+			wake_unlock(&alarm_rtc_wake_lock);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		break;
+	case ANDROID_ALARM_SET_RTC:
+		if (copy_from_user(&new_rtc_time, (void __user *)arg,
+		    sizeof(new_rtc_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		rtc_time_to_tm(new_rtc_time.tv_sec, &rtc_new_rtc_time);
+
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_IO,
+			"set rtc %ld %ld - rtc %02d:%02d:%02d %02d/%02d/%04d\n",
+			new_rtc_time.tv_sec, new_rtc_time.tv_nsec,
+			rtc_new_rtc_time.tm_hour, rtc_new_rtc_time.tm_min,
+			rtc_new_rtc_time.tm_sec, rtc_new_rtc_time.tm_mon + 1,
+			rtc_new_rtc_time.tm_mday,
+			rtc_new_rtc_time.tm_year + 1900);
+
+		mutex_lock(&alarm_setrtc_mutex);
+		spin_lock_irqsave(&alarm_slock, flags);
+		for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++)
+			hrtimer_try_to_cancel(&alarm_timer[i]);
+		getnstimeofday(&tmp_time);
+		elapsed_rtc_delta = timespec_sub(elapsed_rtc_delta,
+					timespec_sub(tmp_time, new_rtc_time));
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		rv = do_settimeofday(&new_rtc_time);
+		spin_lock_irqsave(&alarm_slock, flags);
+		for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++)
+			alarm_start_hrtimer(i);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		if (rv < 0) {
+			ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_ERRORS,
+					      "Failed to set time\n");
+			mutex_unlock(&alarm_setrtc_mutex);
+			goto err1;
+		}
+		rv = rtc_set_time(alarm_rtc_dev, &rtc_new_rtc_time);
+		spin_lock_irqsave(&alarm_slock, flags);
+		alarm_pending |= ANDROID_ALARM_TIME_CHANGE_MASK;
+		wake_up(&alarm_wait_queue);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		mutex_unlock(&alarm_setrtc_mutex);
+		if (rv < 0) {
+			ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_ERRORS,
+			    "Failed to set RTC, time will be lost on reboot\n");
+			goto err1;
+		}
+		break;
+	case ANDROID_ALARM_GET_TIME(0):
+		mutex_lock(&alarm_setrtc_mutex);
+		spin_lock_irqsave(&alarm_slock, flags);
+		if (alarm_type != ANDROID_ALARM_SYSTEMTIME) {
+			getnstimeofday(&tmp_time);
+			if (alarm_type >= ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP)
+				tmp_time = timespec_sub(tmp_time,
+							elapsed_rtc_delta);
+		} else
+			ktime_get_ts(&tmp_time);
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		mutex_unlock(&alarm_setrtc_mutex);
+		if (copy_to_user((void __user *)arg, &tmp_time,
+		    sizeof(tmp_time))) {
+			rv = -EFAULT;
+			goto err1;
+		}
+		break;
+
+	default:
+		rv = -EINVAL;
+		goto err1;
+	}
+err1:
+	return rv;
+}
+
+static int alarm_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	return 0;
+}
+
+static int alarm_release(struct inode *inode, struct file *file)
+{
+	int i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&alarm_slock, flags);
+	if (file->private_data != 0) {
+		for (i = 0; i < ANDROID_ALARM_TYPE_COUNT; i++) {
+			uint32_t alarm_type_mask = 1U << i;
+			if (alarm_enabled & alarm_type_mask) {
+				ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+					"alarm_release: clear alarm, "
+					"pending %d\n",
+					!!(alarm_pending & alarm_type_mask));
+				alarm_enabled &= ~alarm_type_mask;
+			}
+			spin_unlock_irqrestore(&alarm_slock, flags);
+			hrtimer_cancel(&alarm_timer[i]);
+			spin_lock_irqsave(&alarm_slock, flags);
+		}
+		if (alarm_pending | wait_pending) {
+			if (alarm_pending)
+				ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+					"alarm_release: clear pending alarms "
+					"%x\n", alarm_pending);
+			wake_unlock(&alarm_wake_lock);
+			wait_pending = 0;
+			alarm_pending = 0;
+		}
+		alarm_opened = 0;
+	}
+	spin_unlock_irqrestore(&alarm_slock, flags);
+	return 0;
+}
+
+static enum hrtimer_restart alarm_timer_triggered(struct hrtimer *timer)
+{
+	unsigned long flags;
+	enum android_alarm_type alarm_type = (timer - alarm_timer);
+	uint32_t alarm_type_mask = 1U << alarm_type;
+
+
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INT,
+			      "alarm_timer_triggered type %d\n", alarm_type);
+	spin_lock_irqsave(&alarm_slock, flags);
+	if (alarm_enabled & alarm_type_mask) {
+		wake_lock_timeout(&alarm_wake_lock, 5 * HZ);
+		alarm_enabled &= ~alarm_type_mask;
+		alarm_pending |= alarm_type_mask;
+		wake_up(&alarm_wait_queue);
+	}
+	spin_unlock_irqrestore(&alarm_slock, flags);
+	return HRTIMER_NORESTART;
+}
+
+static void alarm_triggered_func(void *p)
+{
+	struct rtc_device *rtc = alarm_rtc_dev;
+	if (!(rtc->irq_data & RTC_AF))
+		return;
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INT, "rtc alarm triggered\n");
+	wake_lock_timeout(&alarm_rtc_wake_lock, 1 * HZ);
+}
+
+int alarm_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	int                 err = 0;
+	unsigned long       flags;
+	struct rtc_wkalrm   rtc_alarm;
+	struct rtc_time     rtc_current_rtc_time;
+	unsigned long       rtc_current_time;
+	unsigned long       rtc_alarm_time;
+	struct timespec     rtc_current_timespec;
+	struct timespec     rtc_delta;
+	struct timespec     elapsed_realtime_alarm_time;
+
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_FLOW,
+			      "alarm_suspend(%p, %d)\n", pdev, state.event);
+	spin_lock_irqsave(&alarm_slock, flags);
+	if (alarm_pending && !wake_lock_active(&alarm_wake_lock)) {
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+				      "alarm pending\n");
+		err = -EBUSY;
+		goto err1;
+	}
+	if (alarm_enabled & ANDROID_ALARM_WAKEUP_MASK) {
+		spin_unlock_irqrestore(&alarm_slock, flags);
+		if (alarm_enabled & ANDROID_ALARM_RTC_WAKEUP_MASK)
+			hrtimer_cancel(&alarm_timer[ANDROID_ALARM_RTC_WAKEUP]);
+		if (alarm_enabled & ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK)
+			hrtimer_cancel(&alarm_timer[
+					ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP]);
+
+		rtc_read_time(alarm_rtc_dev, &rtc_current_rtc_time);
+		rtc_current_timespec.tv_nsec = 0;
+		rtc_tm_to_time(&rtc_current_rtc_time,
+			       &rtc_current_timespec.tv_sec);
+		save_time_delta(&rtc_delta, &rtc_current_timespec);
+		set_normalized_timespec(&elapsed_realtime_alarm_time,
+			alarm_time[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP]
+			.tv_sec + elapsed_rtc_delta.tv_sec,
+			alarm_time[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP]
+			.tv_nsec + elapsed_rtc_delta.tv_nsec);
+		if ((alarm_enabled & ANDROID_ALARM_RTC_WAKEUP_MASK) &&
+		    (!(alarm_enabled &
+		       ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK) ||
+		     timespec_compare(&alarm_time[ANDROID_ALARM_RTC_WAKEUP],
+				      &elapsed_realtime_alarm_time) < 0))
+			rtc_alarm_time = timespec_sub(
+					alarm_time[ANDROID_ALARM_RTC_WAKEUP],
+					rtc_delta).tv_sec;
+		else
+			rtc_alarm_time = timespec_sub(
+				elapsed_realtime_alarm_time, rtc_delta).tv_sec;
+		rtc_time_to_tm(rtc_alarm_time, &rtc_alarm.time);
+		rtc_alarm.enabled = 1;
+		rtc_set_alarm(alarm_rtc_dev, &rtc_alarm);
+		rtc_read_time(alarm_rtc_dev, &rtc_current_rtc_time);
+		rtc_tm_to_time(&rtc_current_rtc_time, &rtc_current_time);
+		ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+			"rtc alarm set at %ld, now %ld, rtc delta %ld.%09ld\n",
+			rtc_alarm_time, rtc_current_time,
+			rtc_delta.tv_sec, rtc_delta.tv_nsec);
+		if (rtc_current_time + 1 >= rtc_alarm_time) {
+			ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+					      "alarm about to go off\n");
+			memset(&rtc_alarm, 0, sizeof(rtc_alarm));
+			rtc_alarm.enabled = 0;
+			rtc_set_alarm(alarm_rtc_dev, &rtc_alarm);
+
+			spin_lock_irqsave(&alarm_slock, flags);
+			wake_lock_timeout(&alarm_rtc_wake_lock, 2 * HZ);
+			alarm_start_hrtimer(ANDROID_ALARM_RTC_WAKEUP);
+			alarm_start_hrtimer(
+				ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP);
+			err = -EBUSY;
+			spin_unlock_irqrestore(&alarm_slock, flags);
+		}
+	} else {
+err1:
+		spin_unlock_irqrestore(&alarm_slock, flags);
+	}
+	return err;
+}
+
+int alarm_resume(struct platform_device *pdev)
+{
+	struct rtc_wkalrm alarm;
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_FLOW,
+			      "alarm_resume(%p)\n", pdev);
+	if (alarm_enabled & ANDROID_ALARM_WAKEUP_MASK) {
+		memset(&alarm, 0, sizeof(alarm));
+		alarm.enabled = 0;
+		rtc_set_alarm(alarm_rtc_dev, &alarm);
+		alarm_start_hrtimer(ANDROID_ALARM_RTC_WAKEUP);
+		alarm_start_hrtimer(ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP);
+	}
+	return 0;
+}
+
+static struct rtc_task alarm_rtc_task = {
+	.func = alarm_triggered_func
+};
+
+static struct file_operations alarm_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = alarm_ioctl,
+	.open = alarm_open,
+	.release = alarm_release,
+};
+
+static struct miscdevice alarm_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "alarm",
+	.fops = &alarm_fops,
+};
+
+static int rtc_alarm_add_device(struct device *dev,
+				struct class_interface *class_intf)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(dev);
+
+	mutex_lock(&alarm_setrtc_mutex);
+
+	if (alarm_rtc_dev) {
+		err = -EBUSY;
+		goto err1;
+	}
+
+	err = misc_register(&alarm_device);
+	if (err)
+		goto err1;
+	alarm_platform_dev =
+		platform_device_register_simple("alarm", -1, NULL, 0);
+	if (IS_ERR(alarm_platform_dev)) {
+		err = PTR_ERR(alarm_platform_dev);
+		goto err2;
+	}
+	err = rtc_irq_register(rtc, &alarm_rtc_task);
+	if (err)
+		goto err3;
+	alarm_rtc_dev = rtc;
+	mutex_unlock(&alarm_setrtc_mutex);
+
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO, "alarm: parent %p\n",
+			      alarm_platform_dev->dev.power.pm_parent);
+	return 0;
+
+err3:
+	platform_device_unregister(alarm_platform_dev);
+err2:
+	misc_deregister(&alarm_device);
+err1:
+	mutex_unlock(&alarm_setrtc_mutex);
+	return err;
+}
+
+static void rtc_alarm_remove_device(struct device *dev,
+				    struct class_interface *class_intf)
+{
+	if (dev == &alarm_rtc_dev->dev) {
+		rtc_irq_unregister(alarm_rtc_dev, &alarm_rtc_task);
+		platform_device_unregister(alarm_platform_dev);
+		misc_deregister(&alarm_device);
+		alarm_rtc_dev = NULL;
+	}
+}
+
+static struct class_interface rtc_alarm_interface = {
+	.add_dev = &rtc_alarm_add_device,
+	.remove_dev = &rtc_alarm_remove_device,
+};
+
+static struct platform_driver alarm_driver = {
+	.suspend = alarm_suspend,
+	.resume = alarm_resume,
+	.driver = {
+		.name = "alarm"
+	}
+};
+
+static int __init alarm_late_init(void)
+{
+	unsigned long   flags;
+	struct timespec system_time;
+
+	/* this needs to run after the rtc is read at boot */
+	spin_lock_irqsave(&alarm_slock, flags);
+	/* We read the current rtc and system time so we can later calulate
+	 * elasped realtime to be (boot_systemtime + rtc - boot_rtc) ==
+	 * (rtc - (boot_rtc - boot_systemtime))
+	 */
+	getnstimeofday(&elapsed_rtc_delta);
+	ktime_get_ts(&system_time);
+	elapsed_rtc_delta = timespec_sub(elapsed_rtc_delta, system_time);
+	spin_unlock_irqrestore(&alarm_slock, flags);
+
+	ANDROID_ALARM_DPRINTF(ANDROID_ALARM_PRINT_INFO,
+		"alarm_late_init: rtc to elapsed realtime delta %ld.%09ld\n",
+		elapsed_rtc_delta.tv_sec, elapsed_rtc_delta.tv_nsec);
+	return 0;
+}
+
+static int __init alarm_init(void)
+{
+	int err;
+	int i;
+
+	for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++) {
+		hrtimer_init(&alarm_timer[i], CLOCK_REALTIME, HRTIMER_MODE_ABS);
+		alarm_timer[i].function = alarm_timer_triggered;
+	}
+	hrtimer_init(&alarm_timer[ANDROID_ALARM_SYSTEMTIME],
+		     CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	alarm_timer[ANDROID_ALARM_SYSTEMTIME].function = alarm_timer_triggered;
+	err = platform_driver_register(&alarm_driver);
+	if (err < 0)
+		goto err1;
+	wake_lock_init(&alarm_wake_lock, WAKE_LOCK_SUSPEND, "alarm");
+	wake_lock_init(&alarm_rtc_wake_lock, WAKE_LOCK_SUSPEND, "alarm_rtc");
+	rtc_alarm_interface.class = rtc_class;
+	err = class_interface_register(&rtc_alarm_interface);
+	if (err < 0)
+		goto err2;
+
+	return 0;
+
+err2:
+	wake_lock_destroy(&alarm_rtc_wake_lock);
+	wake_lock_destroy(&alarm_wake_lock);
+	platform_driver_unregister(&alarm_driver);
+err1:
+	return err;
+}
+
+static void  __exit alarm_exit(void)
+{
+	class_interface_unregister(&rtc_alarm_interface);
+	wake_lock_destroy(&alarm_rtc_wake_lock);
+	wake_lock_destroy(&alarm_wake_lock);
+	platform_driver_unregister(&alarm_driver);
+}
+
+late_initcall(alarm_late_init);
+module_init(alarm_init);
+module_exit(alarm_exit);
+
diff --git a/include/linux/android_alarm.h b/include/linux/android_alarm.h
new file mode 100644
index 000000000000..d0cafd637199
--- /dev/null
+++ b/include/linux/android_alarm.h
@@ -0,0 +1,62 @@
+/* include/linux/android_alarm.h
+ *
+ * Copyright (C) 2006-2007 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_ANDROID_ALARM_H
+#define _LINUX_ANDROID_ALARM_H
+
+#include <linux/ioctl.h>
+#include <linux/time.h>
+
+enum android_alarm_type {
+	/* return code bit numbers or set alarm arg */
+	ANDROID_ALARM_RTC_WAKEUP,
+	ANDROID_ALARM_RTC,
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP,
+	ANDROID_ALARM_ELAPSED_REALTIME,
+	ANDROID_ALARM_SYSTEMTIME,
+
+	ANDROID_ALARM_TYPE_COUNT,
+
+	/* return code bit numbers */
+	/* ANDROID_ALARM_TIME_CHANGE = 16 */
+};
+
+enum android_alarm_return_flags {
+	ANDROID_ALARM_RTC_WAKEUP_MASK = 1U << ANDROID_ALARM_RTC_WAKEUP,
+	ANDROID_ALARM_RTC_MASK = 1U << ANDROID_ALARM_RTC,
+	ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP_MASK =
+				1U << ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP,
+	ANDROID_ALARM_ELAPSED_REALTIME_MASK =
+				1U << ANDROID_ALARM_ELAPSED_REALTIME,
+	ANDROID_ALARM_SYSTEMTIME_MASK = 1U << ANDROID_ALARM_SYSTEMTIME,
+	ANDROID_ALARM_TIME_CHANGE_MASK = 1U << 16
+};
+
+/* Disable alarm */
+#define ANDROID_ALARM_CLEAR(type)           _IO('a', 0 | ((type) << 4))
+
+/* Ack last alarm and wait for next */
+#define ANDROID_ALARM_WAIT                  _IO('a', 1)
+
+#define ALARM_IOW(c, type, size)            _IOW('a', (c) | ((type) << 4), size)
+/* Set alarm */
+#define ANDROID_ALARM_SET(type)             ALARM_IOW(2, type, struct timespec)
+#define ANDROID_ALARM_SET_AND_WAIT(type)    ALARM_IOW(3, type, struct timespec)
+#define ANDROID_ALARM_GET_TIME(type)        ALARM_IOW(4, type, struct timespec)
+#define ANDROID_ALARM_SET_RTC               _IOW('a', 5, struct timespec)
+#define ANDROID_ALARM_BASE_CMD(cmd)         (cmd & ~(_IOC(0, 0, 0xf0, 0)))
+#define ANDROID_ALARM_IOCTL_TO_TYPE(cmd)    (_IOC_NR(cmd) >> 4)
+
+#endif