Patchwork [v3] rtc: max77686: Add driver for max77686 rtc.

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Submitter Jonghwa Lee
Date Feb. 6, 2013, 11:22 a.m.
Message ID <1360149740-19526-1-git-send-email-jonghwa3.lee@samsung.com>
Download mbox | patch
Permalink /patch/218556/
State New
Headers show

Comments

Jonghwa Lee - Feb. 6, 2013, 11:22 a.m.
This patch adds rtc driver for Maxim 77686 multifunction chip.
Max77686 has rtc module in it. and it can be used for timekeeping
clock and system alarm. It provide various operational mode those are
BCD/binary, 24/12hour, am/pm. Driver sets binary/24/ for default.
Maxim 8997 also supports SMPL(Sudden Momentary Power Loss), WTSR
(Watchdog Timeout and Software Reset).

Signed-off-by: Jonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: Myugnjoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
v3
 - Change writing delay 16ms to 14ms
 - Use devm_kzalloc & code clean with Devendra's comments.
v2
 - http://lkml.org/lkml/2012/12/20/57

 drivers/rtc/Kconfig        |   30 +++
 drivers/rtc/Makefile       |    1 +
 drivers/rtc/rtc-max77686.c |  610 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 641 insertions(+)
 create mode 100644 drivers/rtc/rtc-max77686.c

Patch

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 923a9da..fc382af 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -233,6 +233,36 @@  config RTC_DRV_MAX8998
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-max8998.
 
+config RTC_DRV_MAX77686
+	tristate "Maxim MAX77686"
+	depends on MFD_MAX77686
+	help
+	  If you say yes here you will get support for the
+	  RTC of Maxim MAX77686 PMIC.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-max77686.
+
+config MAX77686_RTC_WTSR
+	bool "MAX77686_RTC_WTSR"
+	depends on RTC_DRV_MAX77686
+	help
+	  MAX77686 rtc can supports WTSR(Watchdog Timeout and Software Reset).
+	  WTSR event would keep the PMIC on regardless of PWRHOLD signal.
+	  When PWRHOLD signal is falling, it turns on WTSR timer rather executes
+	  reset imidiately. After timer expiring, it determine to reset the PMIC
+	  depends on PWRHOLD state.
+
+config MAX77686_RTC_SMPL
+	bool "MAX77686_RTC_SMPL"
+	depends on RTC_DRV_MAX77686
+	help
+	  MAX77686 rtc can supports SMPL(Sudden Momentary Power Loss).
+	  SMPL function can be used to intiate a power up sequence after momentarily
+	  loosing contact to the battery pack. If battery goes under UVLO(Under
+	  Lock Out) it starts SMPL timer. After timer exipiring, it checks battery
+	  whether its state recovers from UVLO or not to make power supplies keep on.
+
 config RTC_DRV_RS5C372
 	tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4418ef3..97e7967 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -70,6 +70,7 @@  obj-$(CONFIG_RTC_DRV_MAX8907)	+= rtc-max8907.o
 obj-$(CONFIG_RTC_DRV_MAX8925)	+= rtc-max8925.o
 obj-$(CONFIG_RTC_DRV_MAX8998)	+= rtc-max8998.o
 obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o
+obj-$(CONFIG_RTC_DRV_MAX77686)	+= rtc-max77686.o
 obj-$(CONFIG_RTC_DRV_MC13XXX)	+= rtc-mc13xxx.o
 obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o
 obj-$(CONFIG_RTC_DRV_MPC5121)	+= rtc-mpc5121.o
diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
new file mode 100644
index 0000000..eea0e44
--- /dev/null
+++ b/drivers/rtc/rtc-max77686.c
@@ -0,0 +1,610 @@ 
+/*
+ * RTC driver for Maxim MAX77686
+ *
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ *
+ *  based on rtc-max8997.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/module.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max77686-private.h>
+#include <linux/irqdomain.h>
+#include <linux/regmap.h>
+
+/* 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)
+#define RTC_RBUDR_SHIFT			4
+#define RTC_RBUDR_MASK			(1 << RTC_RBUDR_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)
+
+#define MAX77686_RTC_UPDATE_DELAY	14
+
+enum {
+	RTC_SEC = 0,
+	RTC_MIN,
+	RTC_HOUR,
+	RTC_WEEKDAY,
+	RTC_MONTH,
+	RTC_YEAR,
+	RTC_DATE,
+	RTC_NR_TIME
+};
+
+struct max77686_rtc_info {
+	struct device		*dev;
+	struct max77686_dev	*max77686;
+	struct i2c_client	*rtc;
+	struct rtc_device	*rtc_dev;
+	struct mutex		lock;
+
+	struct regmap		*regmap;
+
+	int virq;
+	int rtc_24hr_mode;
+};
+
+enum MAX77686_RTC_OP {
+	MAX77686_RTC_WRITE,
+	MAX77686_RTC_READ,
+};
+
+static void max77686_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 = fls(data[RTC_WEEKDAY] & 0x7f) - 1;
+	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 max77686_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: MAX77686 RTC cannot handle the year %d."
+			"Assume it's 2000.\n", __func__,
+			1900 + tm->tm_year);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int max77686_rtc_update(struct max77686_rtc_info *info,
+	enum MAX77686_RTC_OP op)
+{
+	int ret;
+	unsigned int data = 0;
+
+	switch (op) {
+	case MAX77686_RTC_WRITE:
+		data = 1 << RTC_UDR_SHIFT;
+		break;
+	case MAX77686_RTC_READ:
+		data = 1 << RTC_RBUDR_SHIFT;
+		break;
+	}
+
+	ret = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_RTC_UPDATE0, data, data);
+	if (ret < 0)
+		dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
+				__func__, ret, data);
+	else {
+		/* Minimum 14ms delay required before RTC update. */
+		msleep(MAX77686_RTC_UPDATE_DELAY);
+	}
+
+	return ret;
+}
+
+static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				MAX77686_RTC_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read time reg(%d)\n",
+			__func__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
+
+	ret = rtc_valid_tm(tm);
+
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	ret = max77686_rtc_tm_to_data(tm, data);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&info->lock);
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_RTC_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
+				ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	unsigned int val;
+	int i, ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
+				__func__, __LINE__, ret);
+		goto out;
+	}
+
+	max77686_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 = regmap_read(info->max77686->regmap, MAX77686_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 max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
+{
+	u8 data[RTC_NR_TIME];
+	int ret, i;
+	struct rtc_time tm;
+
+	if (!mutex_is_locked(&info->lock))
+		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
+
+	for (i = 0; i < RTC_NR_TIME; i++)
+		data[i] &= ~ALARM_ENABLE_MASK;
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+out:
+	return ret;
+}
+
+static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
+{
+	u8 data[RTC_NR_TIME];
+	int ret;
+	struct rtc_time tm;
+
+	if (!mutex_is_locked(&info->lock))
+		dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_READ);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_read(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
+
+	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 = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+out:
+	return ret;
+}
+
+static int max77686_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	u8 data[RTC_NR_TIME];
+	int ret;
+
+	ret = max77686_rtc_tm_to_data(&alrm->time, data);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&info->lock);
+
+	ret = max77686_rtc_stop_alarm(info);
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_bulk_write(info->max77686->rtc_regmap,
+				 MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
+
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+				__func__, ret);
+		goto out;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+	if (ret < 0)
+		goto out;
+
+	if (alrm->enabled)
+		ret = max77686_rtc_start_alarm(info);
+out:
+	mutex_unlock(&info->lock);
+	return ret;
+}
+
+static int max77686_rtc_alarm_irq_enable(struct device *dev,
+					unsigned int enabled)
+{
+	struct max77686_rtc_info *info = dev_get_drvdata(dev);
+	int ret;
+
+	mutex_lock(&info->lock);
+	if (enabled)
+		ret = max77686_rtc_start_alarm(info);
+	else
+		ret = max77686_rtc_stop_alarm(info);
+	mutex_unlock(&info->lock);
+
+	return ret;
+}
+
+static irqreturn_t max77686_rtc_alarm_irq(int irq, void *data)
+{
+	struct max77686_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;
+}
+
+static const struct rtc_class_ops max77686_rtc_ops = {
+	.read_time = max77686_rtc_read_time,
+	.set_time = max77686_rtc_set_time,
+	.read_alarm = max77686_rtc_read_alarm,
+	.set_alarm = max77686_rtc_set_alarm,
+	.alarm_irq_enable = max77686_rtc_alarm_irq_enable,
+};
+
+#ifdef CONFIG_MAX77686_RTC_WTSR
+static void max77686_rtc_enable_wtsr(struct max77686_rtc_info *info,
+					bool enable)
+{
+	int ret;
+	unsigned int 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 = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_WTSR_SMPL_CNTL, mask, val);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
+				__func__, ret);
+		return;
+	}
+
+	max77686_rtc_update(info, MAX77686_RTC_WRITE);
+}
+#else
+static void max77686_rtc_enable_wtsr(struct max77686_rtc_info *info,
+					bool enable) {}
+#endif /* CONFIG_MAX77686_RTC_WTSR */
+#ifdef CONFIG_MAX77686_RTC_SMPL
+static void max77686_rtc_enable_smpl(struct max77686_rtc_info *info,
+					bool enable)
+{
+	int ret;
+	unsigned int 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 = regmap_update_bits(info->max77686->rtc_regmap,
+				 MAX77686_WTSR_SMPL_CNTL, mask, val);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
+				__func__, ret);
+		return;
+	}
+
+	max77686_rtc_update(info, MAX77686_RTC_WRITE);
+
+	val = 0;
+	regmap_read(info->max77686->rtc_regmap, MAX77686_WTSR_SMPL_CNTL, &val);
+	pr_info("%s: WTSR_SMPL(0x%02x)\n", __func__, val);
+}
+#else
+static void max77686_rtc_enable_smpl(struct max77686_rtc_info *info,
+					bool enable) {}
+#endif /* CONFIG_MAX77686_RTC_SMPL */
+
+static int max77686_rtc_init_reg(struct max77686_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 = regmap_bulk_write(info->max77686->rtc_regmap,
+				MAX77686_RTC_CONTROLM, data, 2);
+	if (ret < 0) {
+		dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
+				__func__, ret);
+		return ret;
+	}
+
+	ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
+	return ret;
+}
+
+static struct regmap_config max77686_rtc_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int max77686_rtc_probe(struct platform_device *pdev)
+{
+	struct max77686_dev *max77686 = dev_get_drvdata(pdev->dev.parent);
+	struct max77686_rtc_info *info;
+	int ret, virq;
+
+	pr_info("%s\n", __func__);
+
+	info = devm_kzalloc(&pdev->dev, sizeof(struct max77686_rtc_info),
+				GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	mutex_init(&info->lock);
+	info->dev = &pdev->dev;
+	info->max77686 = max77686;
+	info->rtc = max77686->rtc;
+	info->max77686->rtc_regmap = regmap_init_i2c(info->max77686->rtc,
+					 &max77686_rtc_regmap_config);
+	if (IS_ERR(info->max77686->rtc_regmap)) {
+		ret = PTR_ERR(info->max77686->rtc_regmap);
+		dev_err(info->max77686->dev, "Failed to allocate register map: %d\n",
+				ret);
+		return ret;
+	}
+	platform_set_drvdata(pdev, info);
+
+	ret = max77686_rtc_init_reg(info);
+
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
+		return ret;
+	}
+
+	max77686_rtc_enable_wtsr(info, true);
+	max77686_rtc_enable_smpl(info, true);
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	info->rtc_dev = rtc_device_register("max77686-rtc", &pdev->dev,
+			&max77686_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(info->rtc_dev)) {
+		pr_info("%s: fail\n", __func__);
+
+		ret = PTR_ERR(info->rtc_dev);
+		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+		return ret;
+	}
+	virq = irq_create_mapping(max77686->irq_domain, MAX77686_RTCIRQ_RTCA1);
+	if (!virq)
+		return ret;
+	info->virq = virq;
+
+	ret = request_threaded_irq(virq, NULL, max77686_rtc_alarm_irq, 0,
+			"rtc-alarm0", info);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
+			info->virq, ret);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int max77686_rtc_remove(struct platform_device *pdev)
+{
+	struct max77686_rtc_info *info = platform_get_drvdata(pdev);
+
+	if (info) {
+		free_irq(info->virq, info);
+		rtc_device_unregister(info->rtc_dev);
+	}
+
+	return 0;
+}
+
+static void max77686_rtc_shutdown(struct platform_device *pdev)
+{
+	struct max77686_rtc_info *info = platform_get_drvdata(pdev);
+
+	max77686_rtc_enable_wtsr(info, false);
+	max77686_rtc_enable_smpl(info, false);
+}
+
+static const struct platform_device_id rtc_id[] = {
+	{ "max77686-rtc", 0 },
+	{},
+};
+
+static struct platform_driver max77686_rtc_driver = {
+	.driver		= {
+		.name	= "max77686-rtc",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max77686_rtc_probe,
+	.remove		= max77686_rtc_remove,
+	.shutdown	= max77686_rtc_shutdown,
+	.id_table	= rtc_id,
+};
+
+module_platform_driver(max77686_rtc_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77686 RTC driver");
+MODULE_AUTHOR("<woong.byun@samsung.com>");
+MODULE_LICENSE("GPL");