/*
 * RTC driver for Maxim MAX8997
 *
 * Copyright (C) 2010 Samsung Electronics Co.Ltd
 *
 *  based on rtc-max8998.c
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/mfd/max8997-private.h>
#if defined(CONFIG_RTC_ALARM_BOOT)
#include <linux/io.h>
#include <linux/reboot.h>
#include <mach/regs-clock.h>
#endif

#define MAX8997_RTC_CONTROLM		0x02
#define MAX8997_RTC_CONTROL		0x03
#define MAX8997_RTC_UPDATE1		0x04
#define MAX8997_RTC_UPDATE2		0x05
#define MAX8997_WTSR_SMPL_CNTL		0x06
#define MAX8997_RTC_SEC			0x10
#define MAX8997_RTC_MIN			0x11
#define MAX8997_RTC_HOUR		0x12
#define MAX8997_RTC_WEEKDAY		0x13
#define MAX8997_RTC_MONTH		0x14
#define MAX8997_RTC_YEAR		0x15
#define MAX8997_RTC_DATE		0x16
#define MAX8997_ALARM1_SEC		0x17
#define MAX8997_ALARM1_MIN		0x18
#define MAX8997_ALARM1_HOUR		0x19
#define MAX8997_ALARM1_WEEKDAY		0x1a
#define MAX8997_ALARM1_MONTH		0x1b
#define MAX8997_ALARM1_YEAR		0x1c
#define MAX8997_ALARM1_DATE		0x1d
#define MAX8997_ALARM2_SEC		0x1e
#define MAX8997_ALARM2_MIN		0x1f
#define MAX8997_ALARM2_HOUR		0x20
#define MAX8997_ALARM2_WEEKDAY		0x21
#define MAX8997_ALARM2_MONTH		0x22
#define MAX8997_ALARM2_YEAR		0x23
#define MAX8997_ALARM2_DATE		0x24

/* RTC Control Register */
#define BCD_EN_SHIFT			0
#define BCD_EN_MASK			(1 << BCD_EN_SHIFT)
#define MODEL24_SHIFT			1
#define MODEL24_MASK			(1 << MODEL24_SHIFT)
/* RTC Update Register1 */
#define RTC_UDR_SHIFT			0
#define RTC_UDR_MASK			(1 << RTC_UDR_SHIFT)
/* WTSR and SMPL Register */
#define WTSRT_SHIFT			0
#define SMPLT_SHIFT			2
#define WTSR_EN_SHIFT			6
#define SMPL_EN_SHIFT			7
#define WTSRT_MASK			(3 << WTSRT_SHIFT)
#define SMPLT_MASK			(3 << SMPLT_SHIFT)
#define WTSR_EN_MASK			(1 << WTSR_EN_SHIFT)
#define SMPL_EN_MASK			(1 << SMPL_EN_SHIFT)
/* RTC Hour register */
#define HOUR_PM_SHIFT			6
#define HOUR_PM_MASK			(1 << HOUR_PM_SHIFT)
/* RTC Alarm Enable */
#define ALARM_ENABLE_SHIFT		7
#define ALARM_ENABLE_MASK		(1 << ALARM_ENABLE_SHIFT)

enum {
	RTC_SEC = 0,
	RTC_MIN,
	RTC_HOUR,
	RTC_WEEKDAY,
	RTC_MONTH,
	RTC_YEAR,
	RTC_DATE,
	RTC_NR_TIME
};

struct max8997_rtc_info {
	struct device		*dev;
	struct max8997_dev	*max8997;
	struct i2c_client	*rtc;
	struct rtc_device	*rtc_dev;
	struct mutex		lock;
	int irq;
#if defined(CONFIG_RTC_ALARM_BOOT)
	int irq2;
#endif
	int rtc_24hr_mode;
};

static inline int max8997_rtc_calculate_wday(u8 shifted)
{
	int counter = -1;
	while (shifted) {
		shifted >>= 1;
		counter++;
	}
	return counter;
}

static void max8997_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
				   int rtc_24hr_mode)
{
	tm->tm_sec = data[RTC_SEC] & 0x7f;
	tm->tm_min = data[RTC_MIN] & 0x7f;
	if (rtc_24hr_mode)
		tm->tm_hour = data[RTC_HOUR] & 0x1f;
	else {
		tm->tm_hour = data[RTC_HOUR] & 0x0f;
		if (data[RTC_HOUR] & HOUR_PM_MASK)
			tm->tm_hour += 12;
	}

	tm->tm_wday = max8997_rtc_calculate_wday(data[RTC_WEEKDAY] & 0x7f);
	tm->tm_mday = data[RTC_DATE] & 0x1f;
	tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
	tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
	tm->tm_yday = 0;
	tm->tm_isdst = 0;
}

static int max8997_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
{
	data[RTC_SEC] = tm->tm_sec;
	data[RTC_MIN] = tm->tm_min;
	data[RTC_HOUR] = tm->tm_hour;
	data[RTC_WEEKDAY] = 1 << tm->tm_wday;
	data[RTC_DATE] = tm->tm_mday;
	data[RTC_MONTH] = tm->tm_mon + 1;
	data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0 ;

	if (tm->tm_year < 100) {
		pr_warn("%s: MAX8997 RTC cannot handle the year %d."
			"Assume it's 2000.\n", __func__, 1900 + tm->tm_year);
		return -EINVAL;
	}
	return 0;
}

static inline int max8997_rtc_set_update_reg(struct max8997_rtc_info *info)
{
	int ret;
	u8 data = 1 << RTC_UDR_SHIFT;

	ret = max8997_write_reg(info->rtc, MAX8997_RTC_UPDATE1, data);
	if (ret < 0)
		dev_err(info->dev, "%s: fail to write update reg(%d)\n",
				__func__, ret);
	else {
		/* Minimum 16ms delay required before RTC update.
		 * Otherwise, we may read and update based on out-of-date
		 * value */
		msleep(20);
	}

	return ret;
}

static int max8997_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int ret;

	mutex_lock(&info->lock);
	ret = max8997_bulk_read(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
	mutex_unlock(&info->lock);

	if (ret < 0) {
		dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
				ret);
		return ret;
	}

	max8997_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);

	return rtc_valid_tm(tm);
}

static int max8997_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int ret;

	ret = max8997_rtc_tm_to_data(tm, data);
	if (ret < 0)
		return ret;

	mutex_lock(&info->lock);

	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
				ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
out:
	mutex_unlock(&info->lock);
	return ret;
}

static int max8997_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	u8 val;
	int i, ret;

	mutex_lock(&info->lock);

	ret = max8997_bulk_read(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
			data);
	if (ret < 0) {
		dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
				__func__, __LINE__, ret);
		goto out;
	}

	max8997_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);

	alrm->enabled = 0;
	for (i = 0; i < RTC_NR_TIME; i++) {
		if (data[i] & ALARM_ENABLE_MASK) {
			alrm->enabled = 1;
			break;
		}
	}

	alrm->pending = 0;
	ret = max8997_read_reg(info->max8997->i2c, MAX8997_REG_STATUS1, &val);
	if (ret < 0) {
		dev_err(info->dev, "%s:%d fail to read status1 reg(%d)\n",
				__func__, __LINE__, ret);
		goto out;
	}

	if (val & (1 << 4)) /* RTCA1 */
		alrm->pending = 1;

out:
	mutex_unlock(&info->lock);
	return 0;
}

static int max8997_rtc_stop_alarm(struct max8997_rtc_info *info)
{
	u8 data[RTC_NR_TIME];
	int ret, i;

	if (!mutex_is_locked(&info->lock))
		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);

	ret = max8997_bulk_read(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
				data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
				__func__, ret);
		goto out;
	}

	for (i = 0; i < RTC_NR_TIME; i++)
		data[i] &= ~ALARM_ENABLE_MASK;

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
				 data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
				__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
out:
	return ret;
}

#if defined(CONFIG_RTC_ALARM_BOOT)
static int max8997_rtc_stop_alarm_boot(struct max8997_rtc_info *info)
{
	u8 data[RTC_NR_TIME];
	int ret, i;

	if (!mutex_is_locked(&info->lock))
		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);

	ret = max8997_bulk_read(info->rtc, MAX8997_ALARM2_SEC, RTC_NR_TIME,
				data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
			__func__, ret);
		goto out;
	}

	for (i = 0; i < RTC_NR_TIME; i++)
		data[i] &= ~ALARM_ENABLE_MASK;

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM2_SEC, RTC_NR_TIME,
				 data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
			__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
out:
	return ret;
}
#endif

static int max8997_rtc_start_alarm(struct max8997_rtc_info *info)
{
	u8 data[RTC_NR_TIME];
	int ret;

	if (!mutex_is_locked(&info->lock))
		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);

	ret = max8997_bulk_read(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
				data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
				__func__, ret);
		goto out;
	}

	data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
	if (data[RTC_MONTH] & 0xf)
		data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
	if (data[RTC_YEAR] & 0x7f)
		data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
	if (data[RTC_DATE] & 0x1f)
		data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
				 data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
				__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
out:
	return ret;
}

#if defined(CONFIG_RTC_ALARM_BOOT)
static int max8997_rtc_start_alarm_boot(struct max8997_rtc_info *info)
{
	u8 data[RTC_NR_TIME];
	int ret;

	if (!mutex_is_locked(&info->lock))
		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);

	ret = max8997_bulk_read(info->rtc, MAX8997_ALARM2_SEC, RTC_NR_TIME,
				data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
			__func__, ret);
		goto out;
	}

	data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
	data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
	if (data[RTC_MONTH] & 0xf)
		data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
	if (data[RTC_YEAR] & 0x7f)
		data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
	if (data[RTC_DATE] & 0x1f)
		data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM2_SEC, RTC_NR_TIME,
				 data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
			__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
out:
	return ret;
}
#endif

static int max8997_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int ret;

	ret = max8997_rtc_tm_to_data(&alrm->time, data);
	if (ret < 0)
		return ret;

	dev_info(info->dev, "%s: %d-%02d-%02d %02d:%02d:%02d\n", __func__,
			data[RTC_YEAR] + 2000, data[RTC_MONTH], data[RTC_DATE],
			data[RTC_HOUR], data[RTC_MIN], data[RTC_SEC]);

	mutex_lock(&info->lock);

	ret = max8997_rtc_stop_alarm(info);
	if (ret < 0)
		goto out;

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM1_SEC, RTC_NR_TIME,
				data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
				__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
	if (ret < 0)
		goto out;

	if (alrm->enabled)
		ret = max8997_rtc_start_alarm(info);
out:
	mutex_unlock(&info->lock);
	return ret;
}

#if defined(CONFIG_RTC_ALARM_BOOT)
static int max8997_rtc_set_alarm_boot(struct device *dev,
				      struct rtc_wkalrm *alrm)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	u8 data[RTC_NR_TIME];
	int ret = 0;

	data[RTC_SEC] = alrm->time.tm_sec;
	data[RTC_MIN] = alrm->time.tm_min;
	data[RTC_HOUR] = alrm->time.tm_hour;
	data[RTC_WEEKDAY] = 1 << alrm->time.tm_wday;
	data[RTC_DATE] = alrm->time.tm_mday;
	data[RTC_MONTH] = alrm->time.tm_mon + 1;
	data[RTC_YEAR] =
	    alrm->time.tm_year > 100 ? (alrm->time.tm_year - 100) : 0;

	mutex_lock(&info->lock);

	ret = max8997_rtc_stop_alarm_boot(info);
	if (ret < 0)
		goto out;

	ret = max8997_bulk_write(info->rtc, MAX8997_ALARM2_SEC, RTC_NR_TIME,
				 data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
			__func__, ret);
		goto out;
	}

	ret = max8997_rtc_set_update_reg(info);
	if (ret < 0)
		goto out;

	if (alrm->enabled)
		ret = max8997_rtc_start_alarm_boot(info);

out:
	mutex_unlock(&info->lock);

	return ret;
}
#endif

static int max8997_rtc_alarm_irq_enable(struct device *dev,
					unsigned int enabled)
{
	struct max8997_rtc_info *info = dev_get_drvdata(dev);
	int ret;

	mutex_lock(&info->lock);
	if (enabled)
		ret = max8997_rtc_start_alarm(info);
	else
		ret = max8997_rtc_stop_alarm(info);
	mutex_unlock(&info->lock);

	return ret;
}

static irqreturn_t max8997_rtc_alarm_irq(int irq, void *data)
{
	struct max8997_rtc_info *info = data;

	dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);

	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);

	return IRQ_HANDLED;
}

#if defined(CONFIG_RTC_ALARM_BOOT)
static irqreturn_t max8997_rtc_alarm2_irq(int irq, void *data)
{
	struct max8997_rtc_info *info = data;
	int ret;
	u8 val;

	dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);

	if (__raw_readl(S5P_INFORM2)) {
		ret = max8997_read_reg(info->max8997->i2c,
				       MAX8997_REG_STATUS1, &val);
		if (ret < 0) {
			dev_err(info->dev,
				"%s:%d fail to read status1 reg(%d)\n",
				__func__, __LINE__, ret);
		}
		if (val & 0x20)
			machine_restart(NULL);
	}

	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);

	return IRQ_HANDLED;
}
#endif

static const struct rtc_class_ops max8997_rtc_ops = {
	.read_time = max8997_rtc_read_time,
	.set_time = max8997_rtc_set_time,
	.read_alarm = max8997_rtc_read_alarm,
	.set_alarm = max8997_rtc_set_alarm,
#if defined(CONFIG_RTC_ALARM_BOOT)
	.set_alarm_boot = max8997_rtc_set_alarm_boot,
#endif
	.alarm_irq_enable = max8997_rtc_alarm_irq_enable,
};

static void max8997_rtc_enable_wtsr(struct max8997_rtc_info *info, bool enable)
{
	int ret;
	u8 val, mask;

	if (enable)
		val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
	else
		val = 0;

	mask = WTSR_EN_MASK | WTSRT_MASK;

	dev_info(info->dev, "%s: %s WTSR\n", __func__,
			enable ? "enable" : "disable");

	ret = max8997_update_reg(info->rtc, MAX8997_WTSR_SMPL_CNTL, val, mask);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
				__func__, ret);
		return;
	}

	max8997_rtc_set_update_reg(info);
}

static void max8997_rtc_enable_smpl(struct max8997_rtc_info *info, bool enable)
{
	int ret;
	u8 val, mask;

	if (enable)
		val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
	else
		val = 0;

	mask = SMPL_EN_MASK | SMPLT_MASK;

	dev_info(info->dev, "%s: %s SMPL\n", __func__,
			enable ? "enable" : "disable");

	ret = max8997_update_reg(info->rtc, MAX8997_WTSR_SMPL_CNTL, val, mask);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
				__func__, ret);
		return;
	}

	max8997_rtc_set_update_reg(info);

	val = 0;
	max8997_read_reg(info->rtc, MAX8997_WTSR_SMPL_CNTL, &val);
	pr_info("%s: WTSR_SMPL(0x%02x)\n", __func__, val);
}

static int max8997_rtc_init_reg(struct max8997_rtc_info *info)
{
	u8 data[2];
	int ret;

	/* Set RTC control register : Binary mode, 24hour mdoe */
	data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
	data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);

	info->rtc_24hr_mode = 1;

	ret = max8997_bulk_write(info->rtc, MAX8997_RTC_CONTROLM, 2, data);
	if (ret < 0) {
		dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
				__func__, ret);
		return ret;
	}

	ret = max8997_rtc_set_update_reg(info);
	return ret;
}

static int __devinit max8997_rtc_probe(struct platform_device *pdev)
{
	struct max8997_dev *max8997 = dev_get_drvdata(pdev->dev.parent);
	struct max8997_rtc_info *info;
	int ret;

	info = kzalloc(sizeof(struct max8997_rtc_info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	mutex_init(&info->lock);
	info->dev = &pdev->dev;
	info->max8997 = max8997;
	info->rtc = max8997->rtc;
	info->irq = max8997->irq_base + MAX8997_IRQ_RTCA1;
#if defined(CONFIG_RTC_ALARM_BOOT)
	info->irq2 = max8997->irq_base + MAX8997_IRQ_RTCA2;
#endif

	platform_set_drvdata(pdev, info);

	ret = max8997_rtc_init_reg(info);

	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
		goto err_rtc;
	}

	max8997_rtc_enable_wtsr(info, true);
	max8997_rtc_enable_smpl(info, true);

	device_init_wakeup(&pdev->dev, 1);

	info->rtc_dev = rtc_device_register("max8997-rtc", &pdev->dev,
			&max8997_rtc_ops, THIS_MODULE);

	if (IS_ERR(info->rtc_dev)) {
		ret = PTR_ERR(info->rtc_dev);
		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
		if (ret == 0)
			ret = -EINVAL;
		goto err_rtc;
	}

	ret = request_threaded_irq(info->irq, NULL, max8997_rtc_alarm_irq, 0,
			"rtc-alarm0", info);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
			info->irq, ret);
		goto err_rtc;
	}

#if defined(CONFIG_RTC_ALARM_BOOT)
	ret = request_threaded_irq(info->irq2, NULL, max8997_rtc_alarm2_irq, 0,
			"rtc-alarm0", info);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to request alarm2 IRQ: %d: %d\n",
			info->irq2, ret);
		goto err_rtc;
	}
#endif

	goto out;
err_rtc:
	kfree(info);
	return ret;
out:
	return ret;
}

static int __devexit max8997_rtc_remove(struct platform_device *pdev)
{
	struct max8997_rtc_info *info = platform_get_drvdata(pdev);

	if (info) {
		free_irq(info->irq, info);
#if defined(CONFIG_RTC_ALARM_BOOT)
		free_irq(info->irq2, info);
#endif
		rtc_device_unregister(info->rtc_dev);
		kfree(info);
	}

	return 0;
}

static void max8997_rtc_shutdown(struct platform_device *pdev)
{
	struct max8997_rtc_info *info = platform_get_drvdata(pdev);
	int i;
	u8 val = 0;

	for (i = 0; i < 3; i++) {
		max8997_rtc_enable_wtsr(info, false);
		max8997_read_reg(info->rtc, MAX8997_WTSR_SMPL_CNTL, &val);
		pr_info("%s: WTSR_SMPL reg(0x%02x)\n", __func__, val);
		if (val & WTSR_EN_MASK)
			pr_emerg("%s: fail to disable WTSR\n", __func__);
		else {
			pr_info("%s: success to disable WTSR\n", __func__);
			break;
		}
	}
}

static const struct platform_device_id rtc_id[] = {
	{ "max8997-rtc", 0 },
	{},
};

static struct platform_driver max8997_rtc_driver = {
	.driver		= {
		.name	= "max8997-rtc",
		.owner	= THIS_MODULE,
	},
	.probe		= max8997_rtc_probe,
	.remove		= __devexit_p(max8997_rtc_remove),
	.shutdown	= max8997_rtc_shutdown,
	.id_table	= rtc_id,
};

static int __init max8997_rtc_init(void)
{
	return platform_driver_register(&max8997_rtc_driver);
}
module_init(max8997_rtc_init);

static void __exit max8997_rtc_exit(void)
{
	platform_driver_unregister(&max8997_rtc_driver);
}
module_exit(max8997_rtc_exit);

MODULE_DESCRIPTION("Maxim MAX8997 RTC driver");
MODULE_AUTHOR("<ms925.kim@samsung.com>");
MODULE_LICENSE("GPL");