src/kernel/linux/v4.14/drivers/rtc/rtc-mt6397.c - T103 - Gitiles

 /*
 * Copyright (c) 2014-2015 MediaTek Inc.
 * Author: Tianping.Fang <tianping.fang@mediatek.com>
 *
 * 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.
 *
 * 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 <linux/delay.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
 #include <linux/irqdomain.h>
 #include <linux/platform_device.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/io.h>
 #include <linux/mfd/mt6397/core.h>

 #define RTC_BBPU		0x0000
 #define RTC_BBPU_CBUSY		BIT(6)

 #define RTC_WRTGR		0x003a

 #define RTC_IRQ_STA		0x0002
 #define RTC_IRQ_STA_AL		BIT(0)
 #define RTC_IRQ_STA_LP		BIT(3)

 #define RTC_IRQ_EN		0x0004
 #define RTC_IRQ_EN_AL		BIT(0)
 #define RTC_IRQ_EN_ONESHOT	BIT(2)
 #define RTC_IRQ_EN_LP		BIT(3)
 #define RTC_IRQ_EN_ONESHOT_AL	(RTC_IRQ_EN_ONESHOT | RTC_IRQ_EN_AL)

 #define RTC_AL_MASK		0x0008
 #define RTC_AL_MASK_DOW		BIT(4)

 #define RTC_TC_SEC		0x000a
 /* Min, Hour, Dom... register offset to RTC_TC_SEC */
 #define RTC_OFFSET_SEC		0
 #define RTC_OFFSET_MIN		1
 #define RTC_OFFSET_HOUR		2
 #define RTC_OFFSET_DOM		3
 #define RTC_OFFSET_DOW		4
 #define RTC_OFFSET_MTH		5
 #define RTC_OFFSET_YEAR		6
 #define RTC_OFFSET_COUNT	7

 #define RTC_AL_SEC		0x0018

 #define RTC_AL_SEC_MASK		0x003f
 #define RTC_AL_MIN_MASK		0x003f
 #define RTC_AL_HOU_MASK		0x001f
 #define RTC_AL_DOM_MASK		0x001f
 #define RTC_AL_DOW_MASK		0x0007
 #define RTC_AL_MTH_MASK		0x000f
 #define RTC_AL_YEA_MASK		0x007f

 #define RTC_PDN2		0x002e
 #define RTC_PDN2_PWRON_ALARM	BIT(4)

 #define RTC_MIN_YEAR		1968
 #define RTC_BASE_YEAR		1900
 #define RTC_NUM_YEARS		128
 #define RTC_MIN_YEAR_OFFSET	(RTC_MIN_YEAR - RTC_BASE_YEAR)

 struct mt6397_rtc {
 	struct device		*dev;
 	struct rtc_device	*rtc_dev;
 	struct mutex		lock;
 	struct regmap		*regmap;
 	int			irq;
 	u32			addr_base;
 	u32			wrtgr_offset;
 };

 static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
 {
 	unsigned long timeout = jiffies + HZ;
 	int ret;
 	u32 data;

 	ret = regmap_write(rtc->regmap,
 			   rtc->addr_base + RTC_WRTGR + rtc->wrtgr_offset, 1);
 	if (ret < 0)
 		return ret;

 	while (1) {
 		ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_BBPU,
 				  &data);
 		if (ret < 0)
 			break;
 		if (!(data & RTC_BBPU_CBUSY))
 			break;
 		if (time_after(jiffies, timeout)) {
 			ret = -ETIMEDOUT;
 			break;
 		}
 		cpu_relax();
 	}

 	return ret;
 }

 static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
 {
 	struct mt6397_rtc *rtc = data;
 	u32 irqsta, irqen;
 	int ret;

 	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_STA, &irqsta);
 	if ((ret >= 0) && (irqsta & RTC_IRQ_STA_AL)) {
 		rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
 		irqen = irqsta & ~RTC_IRQ_EN_AL;
 		mutex_lock(&rtc->lock);
 		if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
 				 irqen) == 0)
 			mtk_rtc_write_trigger(rtc);
 		mutex_unlock(&rtc->lock);

 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 static int __mtk_rtc_read_time(struct mt6397_rtc *rtc,
 			       struct rtc_time *tm, int *sec)
 {
 	int ret;
 	u16 data[RTC_OFFSET_COUNT];

 	mutex_lock(&rtc->lock);
 	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
 			       data, RTC_OFFSET_COUNT);
 	if (ret < 0)
 		goto exit;

 	tm->tm_sec = data[RTC_OFFSET_SEC];
 	tm->tm_min = data[RTC_OFFSET_MIN];
 	tm->tm_hour = data[RTC_OFFSET_HOUR];
 	tm->tm_mday = data[RTC_OFFSET_DOM];
 	tm->tm_mon = data[RTC_OFFSET_MTH];
 	tm->tm_year = data[RTC_OFFSET_YEAR];

 	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, sec);
 exit:
 	mutex_unlock(&rtc->lock);
 	return ret;
 }

 static int mtk_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	time64_t time;
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 	int days, sec, ret;

 	do {
 		ret = __mtk_rtc_read_time(rtc, tm, &sec);
 		if (ret < 0)
 			goto exit;
 	} while (sec < tm->tm_sec);

 	/* HW register use 7 bits to store year data, minus
 	 * RTC_MIN_YEAR_OFFSET before write year data to register, and plus
 	 * RTC_MIN_YEAR_OFFSET back after read year from register
 	 */
 	tm->tm_year += RTC_MIN_YEAR_OFFSET;

 	/* HW register start mon from one, but tm_mon start from zero. */
 	tm->tm_mon--;
 	time = rtc_tm_to_time64(tm);

 	/* rtc_tm_to_time64 covert Gregorian date to seconds since
 	 * 01-01-1970 00:00:00, and this date is Thursday.
 	 */
 	days = div_s64(time, 86400);
 	tm->tm_wday = (days + 4) % 7;

 exit:
 	return ret;
 }

 static int mtk_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 	int ret;
 	u16 data[RTC_OFFSET_COUNT];

 	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
 	tm->tm_mon++;

 	data[RTC_OFFSET_SEC] = tm->tm_sec;
 	data[RTC_OFFSET_MIN] = tm->tm_min;
 	data[RTC_OFFSET_HOUR] = tm->tm_hour;
 	data[RTC_OFFSET_DOM] = tm->tm_mday;
 	data[RTC_OFFSET_MTH] = tm->tm_mon;
 	data[RTC_OFFSET_YEAR] = tm->tm_year;

 	mutex_lock(&rtc->lock);
 	ret = regmap_bulk_write(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
 				data, RTC_OFFSET_COUNT);
 	if (ret < 0)
 		goto exit;

 	/* Time register write to hardware after call trigger function */
 	ret = mtk_rtc_write_trigger(rtc);

 exit:
 	mutex_unlock(&rtc->lock);
 	return ret;
 }

 static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	struct rtc_time *tm = &alm->time;
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 	u32 irqen, pdn2;
 	int ret;
 	u16 data[RTC_OFFSET_COUNT];

 	mutex_lock(&rtc->lock);
 	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, &irqen);
 	if (ret < 0)
 		goto err_exit;
 	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_PDN2, &pdn2);
 	if (ret < 0)
 		goto err_exit;

 	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
 			       data, RTC_OFFSET_COUNT);
 	if (ret < 0)
 		goto err_exit;

 	alm->enabled = !!(irqen & RTC_IRQ_EN_AL);
 	alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
 	mutex_unlock(&rtc->lock);

 	tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK;
 	tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK;
 	tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK;
 	tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK;
 	tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK;
 	tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK;

 	tm->tm_year += RTC_MIN_YEAR_OFFSET;
 	tm->tm_mon--;

 	return 0;
 err_exit:
 	mutex_unlock(&rtc->lock);
 	return ret;
 }

 static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	struct rtc_time *tm = &alm->time;
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
 	int ret;
 	u16 data[RTC_OFFSET_COUNT];

 	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
 	tm->tm_mon++;

 	mutex_lock(&rtc->lock);
 	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
 			       data, RTC_OFFSET_COUNT);
 	if (ret < 0)
 		goto exit;

 	data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) |
 				(tm->tm_sec & RTC_AL_SEC_MASK));
 	data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) |
 				(tm->tm_min & RTC_AL_MIN_MASK));
 	data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) |
 				(tm->tm_hour & RTC_AL_HOU_MASK));
 	data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) |
 				(tm->tm_mday & RTC_AL_DOM_MASK));
 	data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) |
 				(tm->tm_mon & RTC_AL_MTH_MASK));
 	data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) |
 				(tm->tm_year & RTC_AL_YEA_MASK));

 	if (alm->enabled) {
 		ret = regmap_bulk_write(rtc->regmap,
 					rtc->addr_base + RTC_AL_SEC,
 					data, RTC_OFFSET_COUNT);
 		if (ret < 0)
 			goto exit;
 		ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_AL_MASK,
 				   RTC_AL_MASK_DOW);
 		if (ret < 0)
 			goto exit;
 		ret = regmap_update_bits(rtc->regmap,
 					 rtc->addr_base + RTC_IRQ_EN,
 					 RTC_IRQ_EN_ONESHOT_AL,
 					 RTC_IRQ_EN_ONESHOT_AL);
 		if (ret < 0)
 			goto exit;
 	} else {
 		ret = regmap_update_bits(rtc->regmap,
 					 rtc->addr_base + RTC_IRQ_EN,
 					 RTC_IRQ_EN_ONESHOT_AL, 0);
 		if (ret < 0)
 			goto exit;
 	}

 	/* All alarm time register write to hardware after calling
 	 * mtk_rtc_write_trigger. This can avoid race condition if alarm
 	 * occur happen during writing alarm time register.
 	 */
 	ret = mtk_rtc_write_trigger(rtc);
 exit:
 	mutex_unlock(&rtc->lock);
 	return ret;
 }

 static const struct rtc_class_ops mtk_rtc_ops = {
 	.read_time  = mtk_rtc_read_time,
 	.set_time   = mtk_rtc_set_time,
 	.read_alarm = mtk_rtc_read_alarm,
 	.set_alarm  = mtk_rtc_set_alarm,
 };

 static int mtk_rtc_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
 	struct mt6397_rtc *rtc;
 	int ret;

 	rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	rtc->addr_base = res->start;

 	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
 	if (res) {
 		rtc->wrtgr_offset = res->start;
 		dev_info(&pdev->dev, "register offset:%d\n", rtc->wrtgr_offset);
 	} else {
 		rtc->wrtgr_offset = 2;
 		dev_err(&pdev->dev, "Failed to get register offset\n");
 	}

 	rtc->irq = platform_get_irq(pdev, 0);
 	if (rtc->irq < 0)
 		return rtc->irq;

 	rtc->regmap = mt6397_chip->regmap;
 	rtc->dev = &pdev->dev;
 	mutex_init(&rtc->lock);

 	platform_set_drvdata(pdev, rtc);

 	rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev);
 	if (IS_ERR(rtc->rtc_dev))
 		return PTR_ERR(rtc->rtc_dev);

 	ret = request_threaded_irq(rtc->irq, NULL,
 				   mtk_rtc_irq_handler_thread,
 				   IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
 				   "mt6397-rtc", rtc);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 			rtc->irq, ret);
 		goto out_dispose_irq;
 	}

 	device_init_wakeup(&pdev->dev, 1);

 	rtc->rtc_dev->ops = &mtk_rtc_ops;

 	ret = rtc_register_device(rtc->rtc_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "register rtc device failed\n");
 		goto out_free_irq;
 	}

 	return 0;

 out_free_irq:
 	free_irq(rtc->irq, rtc->rtc_dev);
 out_dispose_irq:
 	irq_dispose_mapping(rtc->irq);
 	return ret;
 }

 static int mtk_rtc_remove(struct platform_device *pdev)
 {
 	struct mt6397_rtc *rtc = platform_get_drvdata(pdev);

 	free_irq(rtc->irq, rtc->rtc_dev);
 	irq_dispose_mapping(rtc->irq);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int mt6397_rtc_suspend(struct device *dev)
 {
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		enable_irq_wake(rtc->irq);

 	return 0;
 }

 static int mt6397_rtc_resume(struct device *dev)
 {
 	struct mt6397_rtc *rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		disable_irq_wake(rtc->irq);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(mt6397_pm_ops, mt6397_rtc_suspend,
 			mt6397_rtc_resume);

 static const struct of_device_id mt6397_rtc_of_match[] = {
 	{ .compatible = "mediatek,mt6358-rtc", },
 	{ .compatible = "mediatek,mt6397-rtc", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, mt6397_rtc_of_match);

 static struct platform_driver mtk_rtc_driver = {
 	.driver = {
 		.name = "mt6397-rtc",
 		.of_match_table = mt6397_rtc_of_match,
 		.pm = &mt6397_pm_ops,
 	},
 	.probe	= mtk_rtc_probe,
 	.remove = mtk_rtc_remove,
 };

 module_platform_driver(mtk_rtc_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Tianping Fang <tianping.fang@mediatek.com>");
 MODULE_DESCRIPTION("RTC Driver for MediaTek MT6397 PMIC");
	/*
	* Copyright (c) 2014-2015 MediaTek Inc.
	* Author: Tianping.Fang <tianping.fang@mediatek.com>
	*
	* 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.
	*
	* 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 <linux/delay.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/regmap.h>
	#include <linux/rtc.h>
	#include <linux/irqdomain.h>
	#include <linux/platform_device.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/io.h>
	#include <linux/mfd/mt6397/core.h>

	#define RTC_BBPU 0x0000
	#define RTC_BBPU_CBUSY BIT(6)

	#define RTC_WRTGR 0x003a

	#define RTC_IRQ_STA 0x0002
	#define RTC_IRQ_STA_AL BIT(0)
	#define RTC_IRQ_STA_LP BIT(3)

	#define RTC_IRQ_EN 0x0004
	#define RTC_IRQ_EN_AL BIT(0)
	#define RTC_IRQ_EN_ONESHOT BIT(2)
	#define RTC_IRQ_EN_LP BIT(3)
	#define RTC_IRQ_EN_ONESHOT_AL (RTC_IRQ_EN_ONESHOT \| RTC_IRQ_EN_AL)

	#define RTC_AL_MASK 0x0008
	#define RTC_AL_MASK_DOW BIT(4)

	#define RTC_TC_SEC 0x000a
	/* Min, Hour, Dom... register offset to RTC_TC_SEC */
	#define RTC_OFFSET_SEC 0
	#define RTC_OFFSET_MIN 1
	#define RTC_OFFSET_HOUR 2
	#define RTC_OFFSET_DOM 3
	#define RTC_OFFSET_DOW 4
	#define RTC_OFFSET_MTH 5
	#define RTC_OFFSET_YEAR 6
	#define RTC_OFFSET_COUNT 7

	#define RTC_AL_SEC 0x0018

	#define RTC_AL_SEC_MASK 0x003f
	#define RTC_AL_MIN_MASK 0x003f
	#define RTC_AL_HOU_MASK 0x001f
	#define RTC_AL_DOM_MASK 0x001f
	#define RTC_AL_DOW_MASK 0x0007
	#define RTC_AL_MTH_MASK 0x000f
	#define RTC_AL_YEA_MASK 0x007f

	#define RTC_PDN2 0x002e
	#define RTC_PDN2_PWRON_ALARM BIT(4)

	#define RTC_MIN_YEAR 1968
	#define RTC_BASE_YEAR 1900
	#define RTC_NUM_YEARS 128
	#define RTC_MIN_YEAR_OFFSET (RTC_MIN_YEAR - RTC_BASE_YEAR)

	struct mt6397_rtc {
	struct device *dev;
	struct rtc_device *rtc_dev;
	struct mutex lock;
	struct regmap *regmap;
	int irq;
	u32 addr_base;
	u32 wrtgr_offset;
	};

	static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
	{
	unsigned long timeout = jiffies + HZ;
	int ret;
	u32 data;

	ret = regmap_write(rtc->regmap,
	rtc->addr_base + RTC_WRTGR + rtc->wrtgr_offset, 1);
	if (ret < 0)
	return ret;

	while (1) {
	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_BBPU,
	&data);
	if (ret < 0)
	break;
	if (!(data & RTC_BBPU_CBUSY))
	break;
	if (time_after(jiffies, timeout)) {
	ret = -ETIMEDOUT;
	break;
	}
	cpu_relax();
	}

	return ret;
	}

	static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
	{
	struct mt6397_rtc *rtc = data;
	u32 irqsta, irqen;
	int ret;

	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_STA, &irqsta);
	if ((ret >= 0) && (irqsta & RTC_IRQ_STA_AL)) {
	rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF \| RTC_AF);
	irqen = irqsta & ~RTC_IRQ_EN_AL;
	mutex_lock(&rtc->lock);
	if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
	irqen) == 0)
	mtk_rtc_write_trigger(rtc);
	mutex_unlock(&rtc->lock);

	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	static int __mtk_rtc_read_time(struct mt6397_rtc *rtc,
	struct rtc_time tm, int sec)
	{
	int ret;
	u16 data[RTC_OFFSET_COUNT];

	mutex_lock(&rtc->lock);
	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
	data, RTC_OFFSET_COUNT);
	if (ret < 0)
	goto exit;

	tm->tm_sec = data[RTC_OFFSET_SEC];
	tm->tm_min = data[RTC_OFFSET_MIN];
	tm->tm_hour = data[RTC_OFFSET_HOUR];
	tm->tm_mday = data[RTC_OFFSET_DOM];
	tm->tm_mon = data[RTC_OFFSET_MTH];
	tm->tm_year = data[RTC_OFFSET_YEAR];

	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_TC_SEC, sec);
	exit:
	mutex_unlock(&rtc->lock);
	return ret;
	}

	static int mtk_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	time64_t time;
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
	int days, sec, ret;

	do {
	ret = __mtk_rtc_read_time(rtc, tm, &sec);
	if (ret < 0)
	goto exit;
	} while (sec < tm->tm_sec);

	/* HW register use 7 bits to store year data, minus
	* RTC_MIN_YEAR_OFFSET before write year data to register, and plus
	* RTC_MIN_YEAR_OFFSET back after read year from register
	*/
	tm->tm_year += RTC_MIN_YEAR_OFFSET;

	/* HW register start mon from one, but tm_mon start from zero. */
	tm->tm_mon--;
	time = rtc_tm_to_time64(tm);

	/* rtc_tm_to_time64 covert Gregorian date to seconds since
	* 01-01-1970 00:00:00, and this date is Thursday.
	*/
	days = div_s64(time, 86400);
	tm->tm_wday = (days + 4) % 7;

	exit:
	return ret;
	}

	static int mtk_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
	int ret;
	u16 data[RTC_OFFSET_COUNT];

	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
	tm->tm_mon++;

	data[RTC_OFFSET_SEC] = tm->tm_sec;
	data[RTC_OFFSET_MIN] = tm->tm_min;
	data[RTC_OFFSET_HOUR] = tm->tm_hour;
	data[RTC_OFFSET_DOM] = tm->tm_mday;
	data[RTC_OFFSET_MTH] = tm->tm_mon;
	data[RTC_OFFSET_YEAR] = tm->tm_year;

	mutex_lock(&rtc->lock);
	ret = regmap_bulk_write(rtc->regmap, rtc->addr_base + RTC_TC_SEC,
	data, RTC_OFFSET_COUNT);
	if (ret < 0)
	goto exit;

	/* Time register write to hardware after call trigger function */
	ret = mtk_rtc_write_trigger(rtc);

	exit:
	mutex_unlock(&rtc->lock);
	return ret;
	}

	static int mtk_rtc_read_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	struct rtc_time *tm = &alm->time;
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
	u32 irqen, pdn2;
	int ret;
	u16 data[RTC_OFFSET_COUNT];

	mutex_lock(&rtc->lock);
	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_IRQ_EN, &irqen);
	if (ret < 0)
	goto err_exit;
	ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_PDN2, &pdn2);
	if (ret < 0)
	goto err_exit;

	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
	data, RTC_OFFSET_COUNT);
	if (ret < 0)
	goto err_exit;

	alm->enabled = !!(irqen & RTC_IRQ_EN_AL);
	alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
	mutex_unlock(&rtc->lock);

	tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK;
	tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK;
	tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK;
	tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK;
	tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK;
	tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK;

	tm->tm_year += RTC_MIN_YEAR_OFFSET;
	tm->tm_mon--;

	return 0;
	err_exit:
	mutex_unlock(&rtc->lock);
	return ret;
	}

	static int mtk_rtc_set_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	struct rtc_time *tm = &alm->time;
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);
	int ret;
	u16 data[RTC_OFFSET_COUNT];

	tm->tm_year -= RTC_MIN_YEAR_OFFSET;
	tm->tm_mon++;

	mutex_lock(&rtc->lock);
	ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
	data, RTC_OFFSET_COUNT);
	if (ret < 0)
	goto exit;

	data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) \|
	(tm->tm_sec & RTC_AL_SEC_MASK));
	data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) \|
	(tm->tm_min & RTC_AL_MIN_MASK));
	data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) \|
	(tm->tm_hour & RTC_AL_HOU_MASK));
	data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) \|
	(tm->tm_mday & RTC_AL_DOM_MASK));
	data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) \|
	(tm->tm_mon & RTC_AL_MTH_MASK));
	data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) \|
	(tm->tm_year & RTC_AL_YEA_MASK));

	if (alm->enabled) {
	ret = regmap_bulk_write(rtc->regmap,
	rtc->addr_base + RTC_AL_SEC,
	data, RTC_OFFSET_COUNT);
	if (ret < 0)
	goto exit;
	ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_AL_MASK,
	RTC_AL_MASK_DOW);
	if (ret < 0)
	goto exit;
	ret = regmap_update_bits(rtc->regmap,
	rtc->addr_base + RTC_IRQ_EN,
	RTC_IRQ_EN_ONESHOT_AL,
	RTC_IRQ_EN_ONESHOT_AL);
	if (ret < 0)
	goto exit;
	} else {
	ret = regmap_update_bits(rtc->regmap,
	rtc->addr_base + RTC_IRQ_EN,
	RTC_IRQ_EN_ONESHOT_AL, 0);
	if (ret < 0)
	goto exit;
	}

	/* All alarm time register write to hardware after calling
	* mtk_rtc_write_trigger. This can avoid race condition if alarm
	* occur happen during writing alarm time register.
	*/
	ret = mtk_rtc_write_trigger(rtc);
	exit:
	mutex_unlock(&rtc->lock);
	return ret;
	}

	static const struct rtc_class_ops mtk_rtc_ops = {
	.read_time = mtk_rtc_read_time,
	.set_time = mtk_rtc_set_time,
	.read_alarm = mtk_rtc_read_alarm,
	.set_alarm = mtk_rtc_set_alarm,
	};

	static int mtk_rtc_probe(struct platform_device *pdev)
	{
	struct resource *res;
	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
	struct mt6397_rtc *rtc;
	int ret;

	rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL);
	if (!rtc)
	return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	rtc->addr_base = res->start;

	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
	if (res) {
	rtc->wrtgr_offset = res->start;
	dev_info(&pdev->dev, "register offset:%d\n", rtc->wrtgr_offset);
	} else {
	rtc->wrtgr_offset = 2;
	dev_err(&pdev->dev, "Failed to get register offset\n");
	}

	rtc->irq = platform_get_irq(pdev, 0);
	if (rtc->irq < 0)
	return rtc->irq;

	rtc->regmap = mt6397_chip->regmap;
	rtc->dev = &pdev->dev;
	mutex_init(&rtc->lock);

	platform_set_drvdata(pdev, rtc);

	rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev);
	if (IS_ERR(rtc->rtc_dev))
	return PTR_ERR(rtc->rtc_dev);

	ret = request_threaded_irq(rtc->irq, NULL,
	mtk_rtc_irq_handler_thread,
	IRQF_ONESHOT \| IRQF_TRIGGER_HIGH,
	"mt6397-rtc", rtc);
	if (ret) {
	dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
	rtc->irq, ret);
	goto out_dispose_irq;
	}

	device_init_wakeup(&pdev->dev, 1);

	rtc->rtc_dev->ops = &mtk_rtc_ops;

	ret = rtc_register_device(rtc->rtc_dev);
	if (ret) {
	dev_err(&pdev->dev, "register rtc device failed\n");
	goto out_free_irq;
	}

	return 0;

	out_free_irq:
	free_irq(rtc->irq, rtc->rtc_dev);
	out_dispose_irq:
	irq_dispose_mapping(rtc->irq);
	return ret;
	}

	static int mtk_rtc_remove(struct platform_device *pdev)
	{
	struct mt6397_rtc *rtc = platform_get_drvdata(pdev);

	free_irq(rtc->irq, rtc->rtc_dev);
	irq_dispose_mapping(rtc->irq);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int mt6397_rtc_suspend(struct device *dev)
	{
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	enable_irq_wake(rtc->irq);

	return 0;
	}

	static int mt6397_rtc_resume(struct device *dev)
	{
	struct mt6397_rtc *rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	disable_irq_wake(rtc->irq);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(mt6397_pm_ops, mt6397_rtc_suspend,
	mt6397_rtc_resume);

	static const struct of_device_id mt6397_rtc_of_match[] = {
	{ .compatible = "mediatek,mt6358-rtc", },
	{ .compatible = "mediatek,mt6397-rtc", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, mt6397_rtc_of_match);

	static struct platform_driver mtk_rtc_driver = {
	.driver = {
	.name = "mt6397-rtc",
	.of_match_table = mt6397_rtc_of_match,
	.pm = &mt6397_pm_ops,
	},
	.probe = mtk_rtc_probe,
	.remove = mtk_rtc_remove,
	};

	module_platform_driver(mtk_rtc_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Tianping Fang <tianping.fang@mediatek.com>");
	MODULE_DESCRIPTION("RTC Driver for MediaTek MT6397 PMIC");