drivers/rtc/rtc-rc5t619.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * drivers/rtc/rtc-rc5t619.c
  *
  * Real time clock driver for RICOH RC5T619 power management chip.
  *
  * Copyright (C) 2019 Andreas Kemnade
  */

 #include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mfd/rn5t618.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/bcd.h>
 #include <linux/rtc.h>
 #include <linux/slab.h>
 #include <linux/irqdomain.h>

 struct rc5t619_rtc {
 	int			irq;
 	struct rtc_device	*rtc;
 	struct rn5t618 *rn5t618;
 };

 #define CTRL1_ALARM_ENABLED 0x40
 #define CTRL1_24HR 0x20
 #define CTRL1_PERIODIC_MASK 0xf

 #define CTRL2_PON 0x10
 #define CTRL2_ALARM_STATUS 0x80
 #define CTRL2_CTFG 0x4
 #define CTRL2_CTC 0x1

 #define MONTH_CENTFLAG 0x80
 #define HOUR_PMFLAG 0x20
 #define MDAY_DAL_EXT 0x80

 static uint8_t rtc5t619_12hour_bcd2bin(uint8_t hour)
 {
 	if (hour & HOUR_PMFLAG) {
 		hour = bcd2bin(hour & ~HOUR_PMFLAG);
 		return hour == 12 ? 12 : 12 + hour;
 	}

 	hour = bcd2bin(hour);
 	return hour == 12 ? 0 : hour;
 }

 static uint8_t rtc5t619_12hour_bin2bcd(uint8_t hour)
 {
 	if (!hour)
 		return 0x12;

 	if (hour < 12)
 		return bin2bcd(hour);

 	if (hour == 12)
 		return 0x12 | HOUR_PMFLAG;

 	return bin2bcd(hour - 12) | HOUR_PMFLAG;
 }

 static int rc5t619_rtc_periodic_disable(struct device *dev)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	int err;

 	/* disable function */
 	err = regmap_update_bits(rtc->rn5t618->regmap,
 				 RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
 	if (err < 0)
 		return err;

 	/* clear alarm flag and CTFG */
 	err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
 				 CTRL2_ALARM_STATUS | CTRL2_CTFG | CTRL2_CTC,
 				 0);
 	if (err < 0)
 		return err;

 	return 0;
 }

 /* things to be done once after power on */
 static int rc5t619_rtc_pon_setup(struct device *dev)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	int err;
 	unsigned int reg_data;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
 	if (err < 0)
 		return err;

 	/* clear VDET PON */
 	reg_data &= ~(CTRL2_PON | CTRL2_CTC | 0x4a);	/* 0101-1011 */
 	reg_data |= 0x20;	/* 0010-0000 */
 	err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, reg_data);
 	if (err < 0)
 		return err;

 	/* clearing RTC Adjust register */
 	err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, 0);
 	if (err)
 		return err;

 	return regmap_update_bits(rtc->rn5t618->regmap,
 					RN5T618_RTC_CTRL1,
 					CTRL1_24HR, CTRL1_24HR);
 }

 static int rc5t619_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	u8 buff[7];
 	int err;
 	int cent_flag;
 	unsigned int ctrl1;
 	unsigned int ctrl2;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 	if (err < 0)
 		return err;

 	if (ctrl2 & CTRL2_PON)
 		return -EINVAL;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 	if (err < 0)
 		return err;

 	err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 			       buff, sizeof(buff));
 	if (err < 0)
 		return err;

 	if (buff[5] & MONTH_CENTFLAG)
 		cent_flag = 1;
 	else
 		cent_flag = 0;

 	tm->tm_sec  = bcd2bin(buff[0]);
 	tm->tm_min  = bcd2bin(buff[1]);

 	if (ctrl1 & CTRL1_24HR)
 		tm->tm_hour = bcd2bin(buff[2]);
 	else
 		tm->tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);

 	tm->tm_wday = bcd2bin(buff[3]);
 	tm->tm_mday = bcd2bin(buff[4]);
 	tm->tm_mon  = bcd2bin(buff[5] & 0x1f) - 1; /* back to system 0-11 */
 	tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;

 	return 0;
 }

 static int rc5t619_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	u8 buff[7];
 	int err;
 	int cent_flag;
 	unsigned int ctrl1;
 	unsigned int ctrl2;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 	if (err < 0)
 		return err;

 	if (ctrl2 & CTRL2_PON)
 		rc5t619_rtc_pon_setup(dev);

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 	if (err < 0)
 		return err;

 	if (tm->tm_year >= 100)
 		cent_flag = 1;
 	else
 		cent_flag = 0;

 	buff[0] = bin2bcd(tm->tm_sec);
 	buff[1] = bin2bcd(tm->tm_min);

 	if (ctrl1 & CTRL1_24HR)
 		buff[2] = bin2bcd(tm->tm_hour);
 	else
 		buff[2] = rtc5t619_12hour_bin2bcd(tm->tm_hour);

 	buff[3] = bin2bcd(tm->tm_wday);
 	buff[4] = bin2bcd(tm->tm_mday);
 	buff[5] = bin2bcd(tm->tm_mon + 1);	/* system set 0-11 */
 	buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);

 	if (cent_flag)
 		buff[5] |= MONTH_CENTFLAG;

 	err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 				buff, sizeof(buff));
 	if (err < 0) {
 		dev_err(dev, "failed to program new time: %d\n", err);
 		return err;
 	}

 	return 0;
 }

 /* 0-disable, 1-enable */
 static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

 	return regmap_update_bits(rtc->rn5t618->regmap,
 			RN5T618_RTC_CTRL1,
 			CTRL1_ALARM_ENABLED,
 			enabled ? CTRL1_ALARM_ENABLED : 0);
 }

 static int rc5t619_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	u8 buff[6];
 	unsigned int buff_cent;
 	int err;
 	int cent_flag;
 	unsigned int ctrl1;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 	if (err)
 		return err;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
 	if (err < 0) {
 		dev_err(dev, "failed to read time: %d\n", err);
 		return err;
 	}

 	if (buff_cent & MONTH_CENTFLAG)
 		cent_flag = 1;
 	else
 		cent_flag = 0;

 	err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 			       buff, sizeof(buff));
 	if (err)
 		return err;

 	buff[3] = buff[3] & 0x3f;

 	alrm->time.tm_sec  = bcd2bin(buff[0]);
 	alrm->time.tm_min  = bcd2bin(buff[1]);

 	if (ctrl1 & CTRL1_24HR)
 		alrm->time.tm_hour = bcd2bin(buff[2]);
 	else
 		alrm->time.tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);

 	alrm->time.tm_mday = bcd2bin(buff[3]);
 	alrm->time.tm_mon  = bcd2bin(buff[4]) - 1;
 	alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
 	alrm->enabled = !!(ctrl1 & CTRL1_ALARM_ENABLED);
 	dev_dbg(dev, "read alarm: %ptR\n", &alrm->time);

 	return 0;
 }

 static int rc5t619_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 	u8 buff[6];
 	int err;
 	int cent_flag;
 	unsigned int ctrl1;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 	if (err)
 		return err;

 	err = rc5t619_rtc_alarm_enable(dev, 0);
 	if (err < 0)
 		return err;

 	if (rtc->irq == -1)
 		return -EINVAL;

 	if (alrm->enabled == 0)
 		return 0;

 	if (alrm->time.tm_year >= 100)
 		cent_flag = 1;
 	else
 		cent_flag = 0;

 	alrm->time.tm_mon += 1;
 	buff[0] = bin2bcd(alrm->time.tm_sec);
 	buff[1] = bin2bcd(alrm->time.tm_min);

 	if (ctrl1 & CTRL1_24HR)
 		buff[2] = bin2bcd(alrm->time.tm_hour);
 	else
 		buff[2] = rtc5t619_12hour_bin2bcd(alrm->time.tm_hour);

 	buff[3] = bin2bcd(alrm->time.tm_mday);
 	buff[4] = bin2bcd(alrm->time.tm_mon);
 	buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
 	buff[3] |= MDAY_DAL_EXT;

 	err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 				buff, sizeof(buff));
 	if (err < 0)
 		return err;

 	return rc5t619_rtc_alarm_enable(dev, alrm->enabled);
 }

 static const struct rtc_class_ops rc5t619_rtc_ops = {
 	.read_time	= rc5t619_rtc_read_time,
 	.set_time	= rc5t619_rtc_set_time,
 	.set_alarm	= rc5t619_rtc_set_alarm,
 	.read_alarm	= rc5t619_rtc_read_alarm,
 	.alarm_irq_enable = rc5t619_rtc_alarm_enable,
 };

 static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
 {
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

 	/* clear alarm-D status bits.*/
 	return regmap_update_bits(rtc->rn5t618->regmap,
 				RN5T618_RTC_CTRL2,
 				CTRL2_ALARM_STATUS | CTRL2_CTC, 0);
 }

 static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
 {
 	struct device *dev = data;
 	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

 	rc5t619_rtc_alarm_flag_clr(dev);

 	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 	return IRQ_HANDLED;
 }

 static int rc5t619_rtc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 	struct rc5t619_rtc *rtc;
 	unsigned int ctrl2;
 	int err;

 	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;

 	rtc->rn5t618 = rn5t618;

 	dev_set_drvdata(dev, rtc);
 	rtc->irq = -1;

 	if (rn5t618->irq_data)
 		rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 					       RN5T618_IRQ_RTC);

 	if (rtc->irq  < 0)
 		rtc->irq = -1;

 	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 	if (err < 0)
 		return err;

 	/* disable rtc periodic function */
 	err = rc5t619_rtc_periodic_disable(&pdev->dev);
 	if (err)
 		return err;

 	if (ctrl2 & CTRL2_PON) {
 		err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
 		if (err)
 			return err;
 	}

 	rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc->rtc)) {
 		err = PTR_ERR(rtc->rtc);
 		dev_err(dev, "RTC device register: err %d\n", err);
 		return err;
 	}

 	rtc->rtc->ops = &rc5t619_rtc_ops;
 	rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 	rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;

 	/* set interrupt and enable it */
 	if (rtc->irq != -1) {
 		err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 						rc5t619_rtc_irq,
 						IRQF_ONESHOT,
 						"rtc-rc5t619",
 						&pdev->dev);
 		if (err < 0) {
 			dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
 			rtc->irq = -1;

 			err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 			if (err)
 				return err;

 		} else {
 			/* enable wake */
 			device_init_wakeup(&pdev->dev, 1);
 			enable_irq_wake(rtc->irq);
 		}
 	} else {
 		/* system don't want to using alarm interrupt, so close it */
 		err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 		if (err)
 			return err;

 		dev_warn(&pdev->dev, "rc5t619 interrupt is disabled\n");
 	}

 	return devm_rtc_register_device(rtc->rtc);
 }

 static struct platform_driver rc5t619_rtc_driver = {
 	.driver	= {
 		.name	= "rc5t619-rtc",
 	},
 	.probe	= rc5t619_rtc_probe,
 };

 module_platform_driver(rc5t619_rtc_driver);
 MODULE_ALIAS("platform:rc5t619-rtc");
 MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* drivers/rtc/rtc-rc5t619.c
	*
	* Real time clock driver for RICOH RC5T619 power management chip.
	*
	* Copyright (C) 2019 Andreas Kemnade
	*/

	#include <linux/kernel.h>
	#include <linux/device.h>
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/mfd/rn5t618.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/bcd.h>
	#include <linux/rtc.h>
	#include <linux/slab.h>
	#include <linux/irqdomain.h>

	struct rc5t619_rtc {
	int irq;
	struct rtc_device *rtc;
	struct rn5t618 *rn5t618;
	};

	#define CTRL1_ALARM_ENABLED 0x40
	#define CTRL1_24HR 0x20
	#define CTRL1_PERIODIC_MASK 0xf

	#define CTRL2_PON 0x10
	#define CTRL2_ALARM_STATUS 0x80
	#define CTRL2_CTFG 0x4
	#define CTRL2_CTC 0x1

	#define MONTH_CENTFLAG 0x80
	#define HOUR_PMFLAG 0x20
	#define MDAY_DAL_EXT 0x80

	static uint8_t rtc5t619_12hour_bcd2bin(uint8_t hour)
	{
	if (hour & HOUR_PMFLAG) {
	hour = bcd2bin(hour & ~HOUR_PMFLAG);
	return hour == 12 ? 12 : 12 + hour;
	}

	hour = bcd2bin(hour);
	return hour == 12 ? 0 : hour;
	}

	static uint8_t rtc5t619_12hour_bin2bcd(uint8_t hour)
	{
	if (!hour)
	return 0x12;

	if (hour < 12)
	return bin2bcd(hour);

	if (hour == 12)
	return 0x12 \| HOUR_PMFLAG;

	return bin2bcd(hour - 12) \| HOUR_PMFLAG;
	}

	static int rc5t619_rtc_periodic_disable(struct device *dev)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	int err;

	/* disable function */
	err = regmap_update_bits(rtc->rn5t618->regmap,
	RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
	if (err < 0)
	return err;

	/* clear alarm flag and CTFG */
	err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
	CTRL2_ALARM_STATUS \| CTRL2_CTFG \| CTRL2_CTC,
	0);
	if (err < 0)
	return err;

	return 0;
	}

	/* things to be done once after power on */
	static int rc5t619_rtc_pon_setup(struct device *dev)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	int err;
	unsigned int reg_data;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
	if (err < 0)
	return err;

	/* clear VDET PON */
	reg_data &= ~(CTRL2_PON \| CTRL2_CTC \| 0x4a); /* 0101-1011 */
	reg_data \|= 0x20; /* 0010-0000 */
	err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, reg_data);
	if (err < 0)
	return err;

	/* clearing RTC Adjust register */
	err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, 0);
	if (err)
	return err;

	return regmap_update_bits(rtc->rn5t618->regmap,
	RN5T618_RTC_CTRL1,
	CTRL1_24HR, CTRL1_24HR);
	}

	static int rc5t619_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	u8 buff[7];
	int err;
	int cent_flag;
	unsigned int ctrl1;
	unsigned int ctrl2;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
	if (err < 0)
	return err;

	if (ctrl2 & CTRL2_PON)
	return -EINVAL;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
	if (err < 0)
	return err;

	err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
	buff, sizeof(buff));
	if (err < 0)
	return err;

	if (buff[5] & MONTH_CENTFLAG)
	cent_flag = 1;
	else
	cent_flag = 0;

	tm->tm_sec = bcd2bin(buff[0]);
	tm->tm_min = bcd2bin(buff[1]);

	if (ctrl1 & CTRL1_24HR)
	tm->tm_hour = bcd2bin(buff[2]);
	else
	tm->tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);

	tm->tm_wday = bcd2bin(buff[3]);
	tm->tm_mday = bcd2bin(buff[4]);
	tm->tm_mon = bcd2bin(buff[5] & 0x1f) - 1; /* back to system 0-11 */
	tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;

	return 0;
	}

	static int rc5t619_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	u8 buff[7];
	int err;
	int cent_flag;
	unsigned int ctrl1;
	unsigned int ctrl2;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
	if (err < 0)
	return err;

	if (ctrl2 & CTRL2_PON)
	rc5t619_rtc_pon_setup(dev);

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
	if (err < 0)
	return err;

	if (tm->tm_year >= 100)
	cent_flag = 1;
	else
	cent_flag = 0;

	buff[0] = bin2bcd(tm->tm_sec);
	buff[1] = bin2bcd(tm->tm_min);

	if (ctrl1 & CTRL1_24HR)
	buff[2] = bin2bcd(tm->tm_hour);
	else
	buff[2] = rtc5t619_12hour_bin2bcd(tm->tm_hour);

	buff[3] = bin2bcd(tm->tm_wday);
	buff[4] = bin2bcd(tm->tm_mday);
	buff[5] = bin2bcd(tm->tm_mon + 1); /* system set 0-11 */
	buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);

	if (cent_flag)
	buff[5] \|= MONTH_CENTFLAG;

	err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
	buff, sizeof(buff));
	if (err < 0) {
	dev_err(dev, "failed to program new time: %d\n", err);
	return err;
	}

	return 0;
	}

	/* 0-disable, 1-enable */
	static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

	return regmap_update_bits(rtc->rn5t618->regmap,
	RN5T618_RTC_CTRL1,
	CTRL1_ALARM_ENABLED,
	enabled ? CTRL1_ALARM_ENABLED : 0);
	}

	static int rc5t619_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	u8 buff[6];
	unsigned int buff_cent;
	int err;
	int cent_flag;
	unsigned int ctrl1;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
	if (err)
	return err;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
	if (err < 0) {
	dev_err(dev, "failed to read time: %d\n", err);
	return err;
	}

	if (buff_cent & MONTH_CENTFLAG)
	cent_flag = 1;
	else
	cent_flag = 0;

	err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
	buff, sizeof(buff));
	if (err)
	return err;

	buff[3] = buff[3] & 0x3f;

	alrm->time.tm_sec = bcd2bin(buff[0]);
	alrm->time.tm_min = bcd2bin(buff[1]);

	if (ctrl1 & CTRL1_24HR)
	alrm->time.tm_hour = bcd2bin(buff[2]);
	else
	alrm->time.tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);

	alrm->time.tm_mday = bcd2bin(buff[3]);
	alrm->time.tm_mon = bcd2bin(buff[4]) - 1;
	alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
	alrm->enabled = !!(ctrl1 & CTRL1_ALARM_ENABLED);
	dev_dbg(dev, "read alarm: %ptR\n", &alrm->time);

	return 0;
	}

	static int rc5t619_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
	u8 buff[6];
	int err;
	int cent_flag;
	unsigned int ctrl1;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
	if (err)
	return err;

	err = rc5t619_rtc_alarm_enable(dev, 0);
	if (err < 0)
	return err;

	if (rtc->irq == -1)
	return -EINVAL;

	if (alrm->enabled == 0)
	return 0;

	if (alrm->time.tm_year >= 100)
	cent_flag = 1;
	else
	cent_flag = 0;

	alrm->time.tm_mon += 1;
	buff[0] = bin2bcd(alrm->time.tm_sec);
	buff[1] = bin2bcd(alrm->time.tm_min);

	if (ctrl1 & CTRL1_24HR)
	buff[2] = bin2bcd(alrm->time.tm_hour);
	else
	buff[2] = rtc5t619_12hour_bin2bcd(alrm->time.tm_hour);

	buff[3] = bin2bcd(alrm->time.tm_mday);
	buff[4] = bin2bcd(alrm->time.tm_mon);
	buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
	buff[3] \|= MDAY_DAL_EXT;

	err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
	buff, sizeof(buff));
	if (err < 0)
	return err;

	return rc5t619_rtc_alarm_enable(dev, alrm->enabled);
	}

	static const struct rtc_class_ops rc5t619_rtc_ops = {
	.read_time = rc5t619_rtc_read_time,
	.set_time = rc5t619_rtc_set_time,
	.set_alarm = rc5t619_rtc_set_alarm,
	.read_alarm = rc5t619_rtc_read_alarm,
	.alarm_irq_enable = rc5t619_rtc_alarm_enable,
	};

	static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
	{
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

	/* clear alarm-D status bits.*/
	return regmap_update_bits(rtc->rn5t618->regmap,
	RN5T618_RTC_CTRL2,
	CTRL2_ALARM_STATUS \| CTRL2_CTC, 0);
	}

	static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
	{
	struct device *dev = data;
	struct rc5t619_rtc *rtc = dev_get_drvdata(dev);

	rc5t619_rtc_alarm_flag_clr(dev);

	rtc_update_irq(rtc->rtc, 1, RTC_IRQF \| RTC_AF);
	return IRQ_HANDLED;
	}

	static int rc5t619_rtc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
	struct rc5t619_rtc *rtc;
	unsigned int ctrl2;
	int err;

	rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
	if (!rtc)
	return -ENOMEM;

	rtc->rn5t618 = rn5t618;

	dev_set_drvdata(dev, rtc);
	rtc->irq = -1;

	if (rn5t618->irq_data)
	rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
	RN5T618_IRQ_RTC);

	if (rtc->irq < 0)
	rtc->irq = -1;

	err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
	if (err < 0)
	return err;

	/* disable rtc periodic function */
	err = rc5t619_rtc_periodic_disable(&pdev->dev);
	if (err)
	return err;

	if (ctrl2 & CTRL2_PON) {
	err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
	if (err)
	return err;
	}

	rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc->rtc)) {
	err = PTR_ERR(rtc->rtc);
	dev_err(dev, "RTC device register: err %d\n", err);
	return err;
	}

	rtc->rtc->ops = &rc5t619_rtc_ops;
	rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
	rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;

	/* set interrupt and enable it */
	if (rtc->irq != -1) {
	err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
	rc5t619_rtc_irq,
	IRQF_ONESHOT,
	"rtc-rc5t619",
	&pdev->dev);
	if (err < 0) {
	dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
	rtc->irq = -1;

	err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
	if (err)
	return err;

	} else {
	/* enable wake */
	device_init_wakeup(&pdev->dev, 1);
	enable_irq_wake(rtc->irq);
	}
	} else {
	/* system don't want to using alarm interrupt, so close it */
	err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
	if (err)
	return err;

	dev_warn(&pdev->dev, "rc5t619 interrupt is disabled\n");
	}

	return devm_rtc_register_device(rtc->rtc);
	}

	static struct platform_driver rc5t619_rtc_driver = {
	.driver = {
	.name = "rc5t619-rtc",
	},
	.probe = rc5t619_rtc_probe,
	};

	module_platform_driver(rc5t619_rtc_driver);
	MODULE_ALIAS("platform:rc5t619-rtc");
	MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
	MODULE_LICENSE("GPL");