drivers/rtc/rtc-cros-ec.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // RTC driver for ChromeOS Embedded Controller.
 //
 // Copyright (C) 2017 Google, Inc.
 // Author: Stephen Barber <smbarber@chromium.org>

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
 #include <linux/rtc.h>
 #include <linux/slab.h>

 #define DRV_NAME	"cros-ec-rtc"

 #define SECS_PER_DAY	(24 * 60 * 60)

 /**
  * struct cros_ec_rtc - Driver data for EC RTC
  *
  * @cros_ec: Pointer to EC device
  * @rtc: Pointer to RTC device
  * @notifier: Notifier info for responding to EC events
  * @saved_alarm: Alarm to restore when interrupts are reenabled
  */
 struct cros_ec_rtc {
 	struct cros_ec_device *cros_ec;
 	struct rtc_device *rtc;
 	struct notifier_block notifier;
 	u32 saved_alarm;
 };

 static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
 			   u32 *response)
 {
 	int ret;
 	struct {
 		struct cros_ec_command msg;
 		struct ec_response_rtc data;
 	} __packed msg;

 	memset(&msg, 0, sizeof(msg));
 	msg.msg.command = command;
 	msg.msg.insize = sizeof(msg.data);

 	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
 	if (ret < 0)
 		return ret;

 	*response = msg.data.time;

 	return 0;
 }

 static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
 			   u32 param)
 {
 	int ret;
 	struct {
 		struct cros_ec_command msg;
 		struct ec_response_rtc data;
 	} __packed msg;

 	memset(&msg, 0, sizeof(msg));
 	msg.msg.command = command;
 	msg.msg.outsize = sizeof(msg.data);
 	msg.data.time = param;

 	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
 	if (ret < 0)
 		return ret;
 	return 0;
 }

 /* Read the current time from the EC. */
 static int cros_ec_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
 	int ret;
 	u32 time;

 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
 	if (ret) {
 		dev_err(dev, "error getting time: %d\n", ret);
 		return ret;
 	}

 	rtc_time64_to_tm(time, tm);

 	return 0;
 }

 /* Set the current EC time. */
 static int cros_ec_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
 	int ret;
 	time64_t time = rtc_tm_to_time64(tm);

 	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
 	if (ret < 0) {
 		dev_err(dev, "error setting time: %d\n", ret);
 		return ret;
 	}

 	return 0;
 }

 /* Read alarm time from RTC. */
 static int cros_ec_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
 	int ret;
 	u32 current_time, alarm_offset;

 	/*
 	 * The EC host command for getting the alarm is relative (i.e. 5
 	 * seconds from now) whereas rtc_wkalrm is absolute. Get the current
 	 * RTC time first so we can calculate the relative time.
 	 */
 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
 	if (ret < 0) {
 		dev_err(dev, "error getting time: %d\n", ret);
 		return ret;
 	}

 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
 	if (ret < 0) {
 		dev_err(dev, "error getting alarm: %d\n", ret);
 		return ret;
 	}

 	rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);

 	return 0;
 }

 /* Set the EC's RTC alarm. */
 static int cros_ec_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
 	int ret;
 	time64_t alarm_time;
 	u32 current_time, alarm_offset;

 	/*
 	 * The EC host command for setting the alarm is relative
 	 * (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
 	 * Get the current RTC time first so we can calculate the
 	 * relative time.
 	 */
 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
 	if (ret < 0) {
 		dev_err(dev, "error getting time: %d\n", ret);
 		return ret;
 	}

 	alarm_time = rtc_tm_to_time64(&alrm->time);

 	if (alarm_time < 0 || alarm_time > U32_MAX)
 		return -EINVAL;

 	if (!alrm->enabled) {
 		/*
 		 * If the alarm is being disabled, send an alarm
 		 * clear command.
 		 */
 		alarm_offset = EC_RTC_ALARM_CLEAR;
 		cros_ec_rtc->saved_alarm = (u32)alarm_time;
 	} else {
 		/* Don't set an alarm in the past. */
 		if ((u32)alarm_time <= current_time)
 			return -ETIME;

 		alarm_offset = (u32)alarm_time - current_time;
 	}

 	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
 	if (ret < 0) {
 		dev_err(dev, "error setting alarm in %u seconds: %d\n",
 			alarm_offset, ret);
 		/*
 		 * The EC code returns -EINVAL if the alarm time is too
 		 * far in the future. Convert it to the expected error code.
 		 */
 		if (ret == -EINVAL)
 			ret = -ERANGE;
 		return ret;
 	}

 	return 0;
 }

 static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
 					unsigned int enabled)
 {
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
 	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
 	int ret;
 	u32 current_time, alarm_offset, alarm_value;

 	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
 	if (ret < 0) {
 		dev_err(dev, "error getting time: %d\n", ret);
 		return ret;
 	}

 	if (enabled) {
 		/* Restore saved alarm if it's still in the future. */
 		if (cros_ec_rtc->saved_alarm < current_time)
 			alarm_offset = EC_RTC_ALARM_CLEAR;
 		else
 			alarm_offset = cros_ec_rtc->saved_alarm - current_time;

 		ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
 				      alarm_offset);
 		if (ret < 0) {
 			dev_err(dev, "error restoring alarm: %d\n", ret);
 			return ret;
 		}
 	} else {
 		/* Disable alarm, saving the old alarm value. */
 		ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
 				      &alarm_offset);
 		if (ret < 0) {
 			dev_err(dev, "error saving alarm: %d\n", ret);
 			return ret;
 		}

 		alarm_value = current_time + alarm_offset;

 		/*
 		 * If the current EC alarm is already past, we don't want
 		 * to set an alarm when we go through the alarm irq enable
 		 * path.
 		 */
 		if (alarm_value < current_time)
 			cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
 		else
 			cros_ec_rtc->saved_alarm = alarm_value;

 		alarm_offset = EC_RTC_ALARM_CLEAR;
 		ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
 				      alarm_offset);
 		if (ret < 0) {
 			dev_err(dev, "error disabling alarm: %d\n", ret);
 			return ret;
 		}
 	}

 	return 0;
 }

 static int cros_ec_rtc_event(struct notifier_block *nb,
 			     unsigned long queued_during_suspend,
 			     void *_notify)
 {
 	struct cros_ec_rtc *cros_ec_rtc;
 	struct rtc_device *rtc;
 	struct cros_ec_device *cros_ec;
 	u32 host_event;

 	cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
 	rtc = cros_ec_rtc->rtc;
 	cros_ec = cros_ec_rtc->cros_ec;

 	host_event = cros_ec_get_host_event(cros_ec);
 	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
 		rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
 		return NOTIFY_OK;
 	} else {
 		return NOTIFY_DONE;
 	}
 }

 static const struct rtc_class_ops cros_ec_rtc_ops = {
 	.read_time = cros_ec_rtc_read_time,
 	.set_time = cros_ec_rtc_set_time,
 	.read_alarm = cros_ec_rtc_read_alarm,
 	.set_alarm = cros_ec_rtc_set_alarm,
 	.alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
 };

 #ifdef CONFIG_PM_SLEEP
 static int cros_ec_rtc_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);

 	if (device_may_wakeup(dev))
 		return enable_irq_wake(cros_ec_rtc->cros_ec->irq);

 	return 0;
 }

 static int cros_ec_rtc_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);

 	if (device_may_wakeup(dev))
 		return disable_irq_wake(cros_ec_rtc->cros_ec->irq);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
 			 cros_ec_rtc_resume);

 static int cros_ec_rtc_probe(struct platform_device *pdev)
 {
 	struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
 	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
 	struct cros_ec_rtc *cros_ec_rtc;
 	struct rtc_time tm;
 	int ret;

 	cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
 				   GFP_KERNEL);
 	if (!cros_ec_rtc)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, cros_ec_rtc);
 	cros_ec_rtc->cros_ec = cros_ec;

 	/* Get initial time */
 	ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to read RTC time\n");
 		return ret;
 	}

 	ret = device_init_wakeup(&pdev->dev, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to initialize wakeup\n");
 		return ret;
 	}

 	cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(cros_ec_rtc->rtc))
 		return PTR_ERR(cros_ec_rtc->rtc);

 	cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops;
 	cros_ec_rtc->rtc->range_max = U32_MAX;

 	/*
 	 * The RTC on some older Chromebooks can only handle alarms less than
 	 * 24 hours in the future. The only way to find out is to try to set an
 	 * alarm further in the future. If that fails, assume that the RTC
 	 * connected to the EC can only handle less than 24 hours of alarm
 	 * window.
 	 */
 	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, SECS_PER_DAY * 2);
 	if (ret == -EINVAL)
 		cros_ec_rtc->rtc->alarm_offset_max = SECS_PER_DAY - 1;

 	(void)cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
 			      EC_RTC_ALARM_CLEAR);

 	ret = devm_rtc_register_device(cros_ec_rtc->rtc);
 	if (ret)
 		return ret;

 	/* Get RTC events from the EC. */
 	cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
 	ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
 					       &cros_ec_rtc->notifier);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register notifier\n");
 		return ret;
 	}

 	return 0;
 }

 static void cros_ec_rtc_remove(struct platform_device *pdev)
 {
 	struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
 	struct device *dev = &pdev->dev;
 	int ret;

 	ret = blocking_notifier_chain_unregister(
 				&cros_ec_rtc->cros_ec->event_notifier,
 				&cros_ec_rtc->notifier);
 	if (ret)
 		dev_err(dev, "failed to unregister notifier\n");
 }

 static struct platform_driver cros_ec_rtc_driver = {
 	.probe = cros_ec_rtc_probe,
 	.remove_new = cros_ec_rtc_remove,
 	.driver = {
 		.name = DRV_NAME,
 		.pm = &cros_ec_rtc_pm_ops,
 	},
 };

 module_platform_driver(cros_ec_rtc_driver);

 MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
 MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:" DRV_NAME);
	// SPDX-License-Identifier: GPL-2.0
	// RTC driver for ChromeOS Embedded Controller.
	//
	// Copyright (C) 2017 Google, Inc.
	// Author: Stephen Barber <smbarber@chromium.org>

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_data/cros_ec_commands.h>
	#include <linux/platform_data/cros_ec_proto.h>
	#include <linux/platform_device.h>
	#include <linux/rtc.h>
	#include <linux/slab.h>

	#define DRV_NAME "cros-ec-rtc"

	#define SECS_PER_DAY (24 * 60 * 60)

	/**
	* struct cros_ec_rtc - Driver data for EC RTC
	*
	* @cros_ec: Pointer to EC device
	* @rtc: Pointer to RTC device
	* @notifier: Notifier info for responding to EC events
	* @saved_alarm: Alarm to restore when interrupts are reenabled
	*/
	struct cros_ec_rtc {
	struct cros_ec_device *cros_ec;
	struct rtc_device *rtc;
	struct notifier_block notifier;
	u32 saved_alarm;
	};

	static int cros_ec_rtc_get(struct cros_ec_device *cros_ec, u32 command,
	u32 *response)
	{
	int ret;
	struct {
	struct cros_ec_command msg;
	struct ec_response_rtc data;
	} __packed msg;

	memset(&msg, 0, sizeof(msg));
	msg.msg.command = command;
	msg.msg.insize = sizeof(msg.data);

	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
	if (ret < 0)
	return ret;

	*response = msg.data.time;

	return 0;
	}

	static int cros_ec_rtc_set(struct cros_ec_device *cros_ec, u32 command,
	u32 param)
	{
	int ret;
	struct {
	struct cros_ec_command msg;
	struct ec_response_rtc data;
	} __packed msg;

	memset(&msg, 0, sizeof(msg));
	msg.msg.command = command;
	msg.msg.outsize = sizeof(msg.data);
	msg.data.time = param;

	ret = cros_ec_cmd_xfer_status(cros_ec, &msg.msg);
	if (ret < 0)
	return ret;
	return 0;
	}

	/* Read the current time from the EC. */
	static int cros_ec_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
	int ret;
	u32 time;

	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &time);
	if (ret) {
	dev_err(dev, "error getting time: %d\n", ret);
	return ret;
	}

	rtc_time64_to_tm(time, tm);

	return 0;
	}

	/* Set the current EC time. */
	static int cros_ec_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
	int ret;
	time64_t time = rtc_tm_to_time64(tm);

	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_VALUE, (u32)time);
	if (ret < 0) {
	dev_err(dev, "error setting time: %d\n", ret);
	return ret;
	}

	return 0;
	}

	/* Read alarm time from RTC. */
	static int cros_ec_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
	int ret;
	u32 current_time, alarm_offset;

	/*
	* The EC host command for getting the alarm is relative (i.e. 5
	* seconds from now) whereas rtc_wkalrm is absolute. Get the current
	* RTC time first so we can calculate the relative time.
	*/
	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
	if (ret < 0) {
	dev_err(dev, "error getting time: %d\n", ret);
	return ret;
	}

	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM, &alarm_offset);
	if (ret < 0) {
	dev_err(dev, "error getting alarm: %d\n", ret);
	return ret;
	}

	rtc_time64_to_tm(current_time + alarm_offset, &alrm->time);

	return 0;
	}

	/* Set the EC's RTC alarm. */
	static int cros_ec_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
	int ret;
	time64_t alarm_time;
	u32 current_time, alarm_offset;

	/*
	* The EC host command for setting the alarm is relative
	* (i.e. 5 seconds from now) whereas rtc_wkalrm is absolute.
	* Get the current RTC time first so we can calculate the
	* relative time.
	*/
	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
	if (ret < 0) {
	dev_err(dev, "error getting time: %d\n", ret);
	return ret;
	}

	alarm_time = rtc_tm_to_time64(&alrm->time);

	if (alarm_time < 0 \|\| alarm_time > U32_MAX)
	return -EINVAL;

	if (!alrm->enabled) {
	/*
	* If the alarm is being disabled, send an alarm
	* clear command.
	*/
	alarm_offset = EC_RTC_ALARM_CLEAR;
	cros_ec_rtc->saved_alarm = (u32)alarm_time;
	} else {
	/* Don't set an alarm in the past. */
	if ((u32)alarm_time <= current_time)
	return -ETIME;

	alarm_offset = (u32)alarm_time - current_time;
	}

	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, alarm_offset);
	if (ret < 0) {
	dev_err(dev, "error setting alarm in %u seconds: %d\n",
	alarm_offset, ret);
	/*
	* The EC code returns -EINVAL if the alarm time is too
	* far in the future. Convert it to the expected error code.
	*/
	if (ret == -EINVAL)
	ret = -ERANGE;
	return ret;
	}

	return 0;
	}

	static int cros_ec_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(dev);
	struct cros_ec_device *cros_ec = cros_ec_rtc->cros_ec;
	int ret;
	u32 current_time, alarm_offset, alarm_value;

	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_VALUE, &current_time);
	if (ret < 0) {
	dev_err(dev, "error getting time: %d\n", ret);
	return ret;
	}

	if (enabled) {
	/* Restore saved alarm if it's still in the future. */
	if (cros_ec_rtc->saved_alarm < current_time)
	alarm_offset = EC_RTC_ALARM_CLEAR;
	else
	alarm_offset = cros_ec_rtc->saved_alarm - current_time;

	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
	alarm_offset);
	if (ret < 0) {
	dev_err(dev, "error restoring alarm: %d\n", ret);
	return ret;
	}
	} else {
	/* Disable alarm, saving the old alarm value. */
	ret = cros_ec_rtc_get(cros_ec, EC_CMD_RTC_GET_ALARM,
	&alarm_offset);
	if (ret < 0) {
	dev_err(dev, "error saving alarm: %d\n", ret);
	return ret;
	}

	alarm_value = current_time + alarm_offset;

	/*
	* If the current EC alarm is already past, we don't want
	* to set an alarm when we go through the alarm irq enable
	* path.
	*/
	if (alarm_value < current_time)
	cros_ec_rtc->saved_alarm = EC_RTC_ALARM_CLEAR;
	else
	cros_ec_rtc->saved_alarm = alarm_value;

	alarm_offset = EC_RTC_ALARM_CLEAR;
	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
	alarm_offset);
	if (ret < 0) {
	dev_err(dev, "error disabling alarm: %d\n", ret);
	return ret;
	}
	}

	return 0;
	}

	static int cros_ec_rtc_event(struct notifier_block *nb,
	unsigned long queued_during_suspend,
	void *_notify)
	{
	struct cros_ec_rtc *cros_ec_rtc;
	struct rtc_device *rtc;
	struct cros_ec_device *cros_ec;
	u32 host_event;

	cros_ec_rtc = container_of(nb, struct cros_ec_rtc, notifier);
	rtc = cros_ec_rtc->rtc;
	cros_ec = cros_ec_rtc->cros_ec;

	host_event = cros_ec_get_host_event(cros_ec);
	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC)) {
	rtc_update_irq(rtc, 1, RTC_IRQF \| RTC_AF);
	return NOTIFY_OK;
	} else {
	return NOTIFY_DONE;
	}
	}

	static const struct rtc_class_ops cros_ec_rtc_ops = {
	.read_time = cros_ec_rtc_read_time,
	.set_time = cros_ec_rtc_set_time,
	.read_alarm = cros_ec_rtc_read_alarm,
	.set_alarm = cros_ec_rtc_set_alarm,
	.alarm_irq_enable = cros_ec_rtc_alarm_irq_enable,
	};

	#ifdef CONFIG_PM_SLEEP
	static int cros_ec_rtc_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);

	if (device_may_wakeup(dev))
	return enable_irq_wake(cros_ec_rtc->cros_ec->irq);

	return 0;
	}

	static int cros_ec_rtc_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct cros_ec_rtc *cros_ec_rtc = dev_get_drvdata(&pdev->dev);

	if (device_may_wakeup(dev))
	return disable_irq_wake(cros_ec_rtc->cros_ec->irq);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(cros_ec_rtc_pm_ops, cros_ec_rtc_suspend,
	cros_ec_rtc_resume);

	static int cros_ec_rtc_probe(struct platform_device *pdev)
	{
	struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
	struct cros_ec_rtc *cros_ec_rtc;
	struct rtc_time tm;
	int ret;

	cros_ec_rtc = devm_kzalloc(&pdev->dev, sizeof(*cros_ec_rtc),
	GFP_KERNEL);
	if (!cros_ec_rtc)
	return -ENOMEM;

	platform_set_drvdata(pdev, cros_ec_rtc);
	cros_ec_rtc->cros_ec = cros_ec;

	/* Get initial time */
	ret = cros_ec_rtc_read_time(&pdev->dev, &tm);
	if (ret) {
	dev_err(&pdev->dev, "failed to read RTC time\n");
	return ret;
	}

	ret = device_init_wakeup(&pdev->dev, 1);
	if (ret) {
	dev_err(&pdev->dev, "failed to initialize wakeup\n");
	return ret;
	}

	cros_ec_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(cros_ec_rtc->rtc))
	return PTR_ERR(cros_ec_rtc->rtc);

	cros_ec_rtc->rtc->ops = &cros_ec_rtc_ops;
	cros_ec_rtc->rtc->range_max = U32_MAX;

	/*
	* The RTC on some older Chromebooks can only handle alarms less than
	* 24 hours in the future. The only way to find out is to try to set an
	* alarm further in the future. If that fails, assume that the RTC
	* connected to the EC can only handle less than 24 hours of alarm
	* window.
	*/
	ret = cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM, SECS_PER_DAY * 2);
	if (ret == -EINVAL)
	cros_ec_rtc->rtc->alarm_offset_max = SECS_PER_DAY - 1;

	(void)cros_ec_rtc_set(cros_ec, EC_CMD_RTC_SET_ALARM,
	EC_RTC_ALARM_CLEAR);

	ret = devm_rtc_register_device(cros_ec_rtc->rtc);
	if (ret)
	return ret;

	/* Get RTC events from the EC. */
	cros_ec_rtc->notifier.notifier_call = cros_ec_rtc_event;
	ret = blocking_notifier_chain_register(&cros_ec->event_notifier,
	&cros_ec_rtc->notifier);
	if (ret) {
	dev_err(&pdev->dev, "failed to register notifier\n");
	return ret;
	}

	return 0;
	}

	static void cros_ec_rtc_remove(struct platform_device *pdev)
	{
	struct cros_ec_rtc *cros_ec_rtc = platform_get_drvdata(pdev);
	struct device *dev = &pdev->dev;
	int ret;

	ret = blocking_notifier_chain_unregister(
	&cros_ec_rtc->cros_ec->event_notifier,
	&cros_ec_rtc->notifier);
	if (ret)
	dev_err(dev, "failed to unregister notifier\n");
	}

	static struct platform_driver cros_ec_rtc_driver = {
	.probe = cros_ec_rtc_probe,
	.remove_new = cros_ec_rtc_remove,
	.driver = {
	.name = DRV_NAME,
	.pm = &cros_ec_rtc_pm_ops,
	},
	};

	module_platform_driver(cros_ec_rtc_driver);

	MODULE_DESCRIPTION("RTC driver for Chrome OS ECs");
	MODULE_AUTHOR("Stephen Barber <smbarber@chromium.org>");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:" DRV_NAME);