drivers/rtc/rtc-tps65910.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * rtc-tps65910.c -- TPS65910 Real Time Clock interface
  *
  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  * Author: Venu Byravarasu <vbyravarasu@nvidia.com>
  *
  * Based on original TI driver rtc-twl.c
  *   Copyright (C) 2007 MontaVista Software, Inc
  *   Author: Alexandre Rusev <source@mvista.com>
  */

 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/math64.h>
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
 #include <linux/mfd/tps65910.h>

 struct tps65910_rtc {
 	struct rtc_device	*rtc;
 	int irq;
 };

 /* Total number of RTC registers needed to set time*/
 #define NUM_TIME_REGS	(TPS65910_YEARS - TPS65910_SECONDS + 1)

 /* Total number of RTC registers needed to set compensation registers */
 #define NUM_COMP_REGS	(TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)

 /* Min and max values supported with 'offset' interface (swapped sign) */
 #define MIN_OFFSET	(-277761)
 #define MAX_OFFSET	(277778)

 /* Number of ticks per hour */
 #define TICKS_PER_HOUR	(32768 * 3600)

 /* Multiplier for ppb conversions */
 #define PPB_MULT	(1000000000LL)

 static int tps65910_rtc_alarm_irq_enable(struct device *dev,
 					 unsigned int enabled)
 {
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	u8 val = 0;

 	if (enabled)
 		val = TPS65910_RTC_INTERRUPTS_IT_ALARM;

 	return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
 }

 /*
  * Gets current tps65910 RTC time and date parameters.
  *
  * The RTC's time/alarm representation is not what gmtime(3) requires
  * Linux to use:
  *
  *  - Months are 1..12 vs Linux 0-11
  *  - Years are 0..99 vs Linux 1900..N (we assume 21st century)
  */
 static int tps65910_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned char rtc_data[NUM_TIME_REGS];
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	int ret;

 	/* Copy RTC counting registers to static registers or latches */
 	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 		TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
 	if (ret < 0) {
 		dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
 		return ret;
 	}

 	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
 		NUM_TIME_REGS);
 	if (ret < 0) {
 		dev_err(dev, "reading from RTC failed with err:%d\n", ret);
 		return ret;
 	}

 	tm->tm_sec = bcd2bin(rtc_data[0]);
 	tm->tm_min = bcd2bin(rtc_data[1]);
 	tm->tm_hour = bcd2bin(rtc_data[2]);
 	tm->tm_mday = bcd2bin(rtc_data[3]);
 	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
 	tm->tm_year = bcd2bin(rtc_data[5]) + 100;

 	return ret;
 }

 static int tps65910_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned char rtc_data[NUM_TIME_REGS];
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	int ret;

 	rtc_data[0] = bin2bcd(tm->tm_sec);
 	rtc_data[1] = bin2bcd(tm->tm_min);
 	rtc_data[2] = bin2bcd(tm->tm_hour);
 	rtc_data[3] = bin2bcd(tm->tm_mday);
 	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 	rtc_data[5] = bin2bcd(tm->tm_year - 100);

 	/* Stop RTC while updating the RTC time registers */
 	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 		TPS65910_RTC_CTRL_STOP_RTC, 0);
 	if (ret < 0) {
 		dev_err(dev, "RTC stop failed with err:%d\n", ret);
 		return ret;
 	}

 	/* update all the time registers in one shot */
 	ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
 		NUM_TIME_REGS);
 	if (ret < 0) {
 		dev_err(dev, "rtc_set_time error %d\n", ret);
 		return ret;
 	}

 	/* Start back RTC */
 	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 		TPS65910_RTC_CTRL_STOP_RTC, 1);
 	if (ret < 0)
 		dev_err(dev, "RTC start failed with err:%d\n", ret);

 	return ret;
 }

 /*
  * Gets current tps65910 RTC alarm time.
  */
 static int tps65910_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	unsigned char alarm_data[NUM_TIME_REGS];
 	u32 int_val;
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	int ret;

 	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
 		NUM_TIME_REGS);
 	if (ret < 0) {
 		dev_err(dev, "rtc_read_alarm error %d\n", ret);
 		return ret;
 	}

 	alm->time.tm_sec = bcd2bin(alarm_data[0]);
 	alm->time.tm_min = bcd2bin(alarm_data[1]);
 	alm->time.tm_hour = bcd2bin(alarm_data[2]);
 	alm->time.tm_mday = bcd2bin(alarm_data[3]);
 	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
 	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;

 	ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
 	if (ret < 0)
 		return ret;

 	if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
 		alm->enabled = 1;

 	return ret;
 }

 static int tps65910_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 {
 	unsigned char alarm_data[NUM_TIME_REGS];
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	int ret;

 	ret = tps65910_rtc_alarm_irq_enable(dev, 0);
 	if (ret)
 		return ret;

 	alarm_data[0] = bin2bcd(alm->time.tm_sec);
 	alarm_data[1] = bin2bcd(alm->time.tm_min);
 	alarm_data[2] = bin2bcd(alm->time.tm_hour);
 	alarm_data[3] = bin2bcd(alm->time.tm_mday);
 	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
 	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);

 	/* update all the alarm registers in one shot */
 	ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
 		alarm_data, NUM_TIME_REGS);
 	if (ret) {
 		dev_err(dev, "rtc_set_alarm error %d\n", ret);
 		return ret;
 	}

 	if (alm->enabled)
 		ret = tps65910_rtc_alarm_irq_enable(dev, 1);

 	return ret;
 }

 static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
 {
 	unsigned char comp_data[NUM_COMP_REGS];
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	s16 value;
 	int ret;

 	/*
 	 * TPS65910 uses two's complement 16 bit value for compensation for RTC
 	 * crystal inaccuracies. One time every hour when seconds counter
 	 * increments from 0 to 1 compensation value will be added to internal
 	 * RTC counter value.
 	 *
 	 * Compensation value 0x7FFF is prohibited value.
 	 *
 	 * Valid range for compensation value: [-32768 .. 32766]
 	 */
 	if ((calibration < -32768) || (calibration > 32766)) {
 		dev_err(dev, "RTC calibration value out of range: %d\n",
 			calibration);
 		return -EINVAL;
 	}

 	value = (s16)calibration;

 	comp_data[0] = (u16)value & 0xFF;
 	comp_data[1] = ((u16)value >> 8) & 0xFF;

 	/* Update all the compensation registers in one shot */
 	ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
 		comp_data, NUM_COMP_REGS);
 	if (ret < 0) {
 		dev_err(dev, "rtc_set_calibration error: %d\n", ret);
 		return ret;
 	}

 	/* Enable automatic compensation */
 	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
 		TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
 	if (ret < 0)
 		dev_err(dev, "auto_comp enable failed with error: %d\n", ret);

 	return ret;
 }

 static int tps65910_rtc_get_calibration(struct device *dev, int *calibration)
 {
 	unsigned char comp_data[NUM_COMP_REGS];
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	unsigned int ctrl;
 	u16 value;
 	int ret;

 	ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
 	if (ret < 0)
 		return ret;

 	/* If automatic compensation is not enabled report back zero */
 	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
 		*calibration = 0;
 		return 0;
 	}

 	ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
 		NUM_COMP_REGS);
 	if (ret < 0) {
 		dev_err(dev, "rtc_get_calibration error: %d\n", ret);
 		return ret;
 	}

 	value = (u16)comp_data[0] | ((u16)comp_data[1] << 8);

 	*calibration = (s16)value;

 	return 0;
 }

 static int tps65910_read_offset(struct device *dev, long *offset)
 {
 	int calibration;
 	s64 tmp;
 	int ret;

 	ret = tps65910_rtc_get_calibration(dev, &calibration);
 	if (ret < 0)
 		return ret;

 	/* Convert from RTC calibration register format to ppb format */
 	tmp = calibration * (s64)PPB_MULT;
 	if (tmp < 0)
 		tmp -= TICKS_PER_HOUR / 2LL;
 	else
 		tmp += TICKS_PER_HOUR / 2LL;
 	tmp = div_s64(tmp, TICKS_PER_HOUR);

 	/* Offset value operates in negative way, so swap sign */
 	*offset = (long)-tmp;

 	return 0;
 }

 static int tps65910_set_offset(struct device *dev, long offset)
 {
 	int calibration;
 	s64 tmp;
 	int ret;

 	/* Make sure offset value is within supported range */
 	if (offset < MIN_OFFSET || offset > MAX_OFFSET)
 		return -ERANGE;

 	/* Convert from ppb format to RTC calibration register format */
 	tmp = offset * (s64)TICKS_PER_HOUR;
 	if (tmp < 0)
 		tmp -= PPB_MULT / 2LL;
 	else
 		tmp += PPB_MULT / 2LL;
 	tmp = div_s64(tmp, PPB_MULT);

 	/* Offset value operates in negative way, so swap sign */
 	calibration = (int)-tmp;

 	ret = tps65910_rtc_set_calibration(dev, calibration);

 	return ret;
 }

 static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
 {
 	struct device *dev = rtc;
 	unsigned long events = 0;
 	struct tps65910 *tps = dev_get_drvdata(dev->parent);
 	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
 	int ret;
 	u32 rtc_reg;

 	ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 	if (ret)
 		return IRQ_NONE;

 	if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
 		events = RTC_IRQF | RTC_AF;

 	ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
 	if (ret)
 		return IRQ_NONE;

 	/* Notify RTC core on event */
 	rtc_update_irq(tps_rtc->rtc, 1, events);

 	return IRQ_HANDLED;
 }

 static const struct rtc_class_ops tps65910_rtc_ops = {
 	.read_time	= tps65910_rtc_read_time,
 	.set_time	= tps65910_rtc_set_time,
 	.read_alarm	= tps65910_rtc_read_alarm,
 	.set_alarm	= tps65910_rtc_set_alarm,
 	.alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
 	.read_offset	= tps65910_read_offset,
 	.set_offset	= tps65910_set_offset,
 };

 static int tps65910_rtc_probe(struct platform_device *pdev)
 {
 	struct tps65910 *tps65910 = NULL;
 	struct tps65910_rtc *tps_rtc = NULL;
 	int ret;
 	int irq;
 	u32 rtc_reg;

 	tps65910 = dev_get_drvdata(pdev->dev.parent);

 	tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
 			GFP_KERNEL);
 	if (!tps_rtc)
 		return -ENOMEM;

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

 	/* Clear pending interrupts */
 	ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
 	if (ret < 0)
 		return ret;

 	ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
 	if (ret < 0)
 		return ret;

 	dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");

 	/* Enable RTC digital power domain */
 	ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
 		DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
 	if (ret < 0)
 		return ret;

 	rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
 	ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
 	if (ret < 0)
 		return ret;

 	platform_set_drvdata(pdev, tps_rtc);

 	irq  = platform_get_irq(pdev, 0);
 	if (irq <= 0) {
 		dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
 			irq);
 		return -ENXIO;
 	}

 	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 		tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
 		dev_name(&pdev->dev), &pdev->dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "IRQ is not free.\n");
 		return ret;
 	}
 	tps_rtc->irq = irq;
 	device_set_wakeup_capable(&pdev->dev, 1);

 	tps_rtc->rtc->ops = &tps65910_rtc_ops;
 	tps_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 	tps_rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;

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

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int tps65910_rtc_suspend(struct device *dev)
 {
 	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		enable_irq_wake(tps_rtc->irq);
 	return 0;
 }

 static int tps65910_rtc_resume(struct device *dev)
 {
 	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		disable_irq_wake(tps_rtc->irq);
 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
 			tps65910_rtc_resume);

 static struct platform_driver tps65910_rtc_driver = {
 	.probe		= tps65910_rtc_probe,
 	.driver		= {
 		.name	= "tps65910-rtc",
 		.pm	= &tps65910_rtc_pm_ops,
 	},
 };

 module_platform_driver(tps65910_rtc_driver);
 MODULE_ALIAS("platform:rtc-tps65910");
 MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* rtc-tps65910.c -- TPS65910 Real Time Clock interface
	*
	* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
	* Author: Venu Byravarasu <vbyravarasu@nvidia.com>
	*
	* Based on original TI driver rtc-twl.c
	* Copyright (C) 2007 MontaVista Software, Inc
	* Author: Alexandre Rusev <source@mvista.com>
	*/

	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/rtc.h>
	#include <linux/bcd.h>
	#include <linux/math64.h>
	#include <linux/platform_device.h>
	#include <linux/interrupt.h>
	#include <linux/mfd/tps65910.h>

	struct tps65910_rtc {
	struct rtc_device *rtc;
	int irq;
	};

	/* Total number of RTC registers needed to set time*/
	#define NUM_TIME_REGS (TPS65910_YEARS - TPS65910_SECONDS + 1)

	/* Total number of RTC registers needed to set compensation registers */
	#define NUM_COMP_REGS (TPS65910_RTC_COMP_MSB - TPS65910_RTC_COMP_LSB + 1)

	/* Min and max values supported with 'offset' interface (swapped sign) */
	#define MIN_OFFSET (-277761)
	#define MAX_OFFSET (277778)

	/* Number of ticks per hour */
	#define TICKS_PER_HOUR (32768 * 3600)

	/* Multiplier for ppb conversions */
	#define PPB_MULT (1000000000LL)

	static int tps65910_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	u8 val = 0;

	if (enabled)
	val = TPS65910_RTC_INTERRUPTS_IT_ALARM;

	return regmap_write(tps->regmap, TPS65910_RTC_INTERRUPTS, val);
	}

	/*
	* Gets current tps65910 RTC time and date parameters.
	*
	* The RTC's time/alarm representation is not what gmtime(3) requires
	* Linux to use:
	*
	* - Months are 1..12 vs Linux 0-11
	* - Years are 0..99 vs Linux 1900..N (we assume 21st century)
	*/
	static int tps65910_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	unsigned char rtc_data[NUM_TIME_REGS];
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	int ret;

	/* Copy RTC counting registers to static registers or latches */
	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
	TPS65910_RTC_CTRL_GET_TIME, TPS65910_RTC_CTRL_GET_TIME);
	if (ret < 0) {
	dev_err(dev, "RTC CTRL reg update failed with err:%d\n", ret);
	return ret;
	}

	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, rtc_data,
	NUM_TIME_REGS);
	if (ret < 0) {
	dev_err(dev, "reading from RTC failed with err:%d\n", ret);
	return ret;
	}

	tm->tm_sec = bcd2bin(rtc_data[0]);
	tm->tm_min = bcd2bin(rtc_data[1]);
	tm->tm_hour = bcd2bin(rtc_data[2]);
	tm->tm_mday = bcd2bin(rtc_data[3]);
	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
	tm->tm_year = bcd2bin(rtc_data[5]) + 100;

	return ret;
	}

	static int tps65910_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	unsigned char rtc_data[NUM_TIME_REGS];
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	int ret;

	rtc_data[0] = bin2bcd(tm->tm_sec);
	rtc_data[1] = bin2bcd(tm->tm_min);
	rtc_data[2] = bin2bcd(tm->tm_hour);
	rtc_data[3] = bin2bcd(tm->tm_mday);
	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
	rtc_data[5] = bin2bcd(tm->tm_year - 100);

	/* Stop RTC while updating the RTC time registers */
	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
	TPS65910_RTC_CTRL_STOP_RTC, 0);
	if (ret < 0) {
	dev_err(dev, "RTC stop failed with err:%d\n", ret);
	return ret;
	}

	/* update all the time registers in one shot */
	ret = regmap_bulk_write(tps->regmap, TPS65910_SECONDS, rtc_data,
	NUM_TIME_REGS);
	if (ret < 0) {
	dev_err(dev, "rtc_set_time error %d\n", ret);
	return ret;
	}

	/* Start back RTC */
	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
	TPS65910_RTC_CTRL_STOP_RTC, 1);
	if (ret < 0)
	dev_err(dev, "RTC start failed with err:%d\n", ret);

	return ret;
	}

	/*
	* Gets current tps65910 RTC alarm time.
	*/
	static int tps65910_rtc_read_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	unsigned char alarm_data[NUM_TIME_REGS];
	u32 int_val;
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	int ret;

	ret = regmap_bulk_read(tps->regmap, TPS65910_SECONDS, alarm_data,
	NUM_TIME_REGS);
	if (ret < 0) {
	dev_err(dev, "rtc_read_alarm error %d\n", ret);
	return ret;
	}

	alm->time.tm_sec = bcd2bin(alarm_data[0]);
	alm->time.tm_min = bcd2bin(alarm_data[1]);
	alm->time.tm_hour = bcd2bin(alarm_data[2]);
	alm->time.tm_mday = bcd2bin(alarm_data[3]);
	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;

	ret = regmap_read(tps->regmap, TPS65910_RTC_INTERRUPTS, &int_val);
	if (ret < 0)
	return ret;

	if (int_val & TPS65910_RTC_INTERRUPTS_IT_ALARM)
	alm->enabled = 1;

	return ret;
	}

	static int tps65910_rtc_set_alarm(struct device dev, struct rtc_wkalrm alm)
	{
	unsigned char alarm_data[NUM_TIME_REGS];
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	int ret;

	ret = tps65910_rtc_alarm_irq_enable(dev, 0);
	if (ret)
	return ret;

	alarm_data[0] = bin2bcd(alm->time.tm_sec);
	alarm_data[1] = bin2bcd(alm->time.tm_min);
	alarm_data[2] = bin2bcd(alm->time.tm_hour);
	alarm_data[3] = bin2bcd(alm->time.tm_mday);
	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);

	/* update all the alarm registers in one shot */
	ret = regmap_bulk_write(tps->regmap, TPS65910_ALARM_SECONDS,
	alarm_data, NUM_TIME_REGS);
	if (ret) {
	dev_err(dev, "rtc_set_alarm error %d\n", ret);
	return ret;
	}

	if (alm->enabled)
	ret = tps65910_rtc_alarm_irq_enable(dev, 1);

	return ret;
	}

	static int tps65910_rtc_set_calibration(struct device *dev, int calibration)
	{
	unsigned char comp_data[NUM_COMP_REGS];
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	s16 value;
	int ret;

	/*
	* TPS65910 uses two's complement 16 bit value for compensation for RTC
	* crystal inaccuracies. One time every hour when seconds counter
	* increments from 0 to 1 compensation value will be added to internal
	* RTC counter value.
	*
	* Compensation value 0x7FFF is prohibited value.
	*
	* Valid range for compensation value: [-32768 .. 32766]
	*/
	if ((calibration < -32768) \|\| (calibration > 32766)) {
	dev_err(dev, "RTC calibration value out of range: %d\n",
	calibration);
	return -EINVAL;
	}

	value = (s16)calibration;

	comp_data[0] = (u16)value & 0xFF;
	comp_data[1] = ((u16)value >> 8) & 0xFF;

	/* Update all the compensation registers in one shot */
	ret = regmap_bulk_write(tps->regmap, TPS65910_RTC_COMP_LSB,
	comp_data, NUM_COMP_REGS);
	if (ret < 0) {
	dev_err(dev, "rtc_set_calibration error: %d\n", ret);
	return ret;
	}

	/* Enable automatic compensation */
	ret = regmap_update_bits(tps->regmap, TPS65910_RTC_CTRL,
	TPS65910_RTC_CTRL_AUTO_COMP, TPS65910_RTC_CTRL_AUTO_COMP);
	if (ret < 0)
	dev_err(dev, "auto_comp enable failed with error: %d\n", ret);

	return ret;
	}

	static int tps65910_rtc_get_calibration(struct device dev, int calibration)
	{
	unsigned char comp_data[NUM_COMP_REGS];
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	unsigned int ctrl;
	u16 value;
	int ret;

	ret = regmap_read(tps->regmap, TPS65910_RTC_CTRL, &ctrl);
	if (ret < 0)
	return ret;

	/* If automatic compensation is not enabled report back zero */
	if (!(ctrl & TPS65910_RTC_CTRL_AUTO_COMP)) {
	*calibration = 0;
	return 0;
	}

	ret = regmap_bulk_read(tps->regmap, TPS65910_RTC_COMP_LSB, comp_data,
	NUM_COMP_REGS);
	if (ret < 0) {
	dev_err(dev, "rtc_get_calibration error: %d\n", ret);
	return ret;
	}

	value = (u16)comp_data[0] \| ((u16)comp_data[1] << 8);

	*calibration = (s16)value;

	return 0;
	}

	static int tps65910_read_offset(struct device dev, long offset)
	{
	int calibration;
	s64 tmp;
	int ret;

	ret = tps65910_rtc_get_calibration(dev, &calibration);
	if (ret < 0)
	return ret;

	/* Convert from RTC calibration register format to ppb format */
	tmp = calibration * (s64)PPB_MULT;
	if (tmp < 0)
	tmp -= TICKS_PER_HOUR / 2LL;
	else
	tmp += TICKS_PER_HOUR / 2LL;
	tmp = div_s64(tmp, TICKS_PER_HOUR);

	/* Offset value operates in negative way, so swap sign */
	*offset = (long)-tmp;

	return 0;
	}

	static int tps65910_set_offset(struct device *dev, long offset)
	{
	int calibration;
	s64 tmp;
	int ret;

	/* Make sure offset value is within supported range */
	if (offset < MIN_OFFSET \|\| offset > MAX_OFFSET)
	return -ERANGE;

	/* Convert from ppb format to RTC calibration register format */
	tmp = offset * (s64)TICKS_PER_HOUR;
	if (tmp < 0)
	tmp -= PPB_MULT / 2LL;
	else
	tmp += PPB_MULT / 2LL;
	tmp = div_s64(tmp, PPB_MULT);

	/* Offset value operates in negative way, so swap sign */
	calibration = (int)-tmp;

	ret = tps65910_rtc_set_calibration(dev, calibration);

	return ret;
	}

	static irqreturn_t tps65910_rtc_interrupt(int irq, void *rtc)
	{
	struct device *dev = rtc;
	unsigned long events = 0;
	struct tps65910 *tps = dev_get_drvdata(dev->parent);
	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);
	int ret;
	u32 rtc_reg;

	ret = regmap_read(tps->regmap, TPS65910_RTC_STATUS, &rtc_reg);
	if (ret)
	return IRQ_NONE;

	if (rtc_reg & TPS65910_RTC_STATUS_ALARM)
	events = RTC_IRQF \| RTC_AF;

	ret = regmap_write(tps->regmap, TPS65910_RTC_STATUS, rtc_reg);
	if (ret)
	return IRQ_NONE;

	/* Notify RTC core on event */
	rtc_update_irq(tps_rtc->rtc, 1, events);

	return IRQ_HANDLED;
	}

	static const struct rtc_class_ops tps65910_rtc_ops = {
	.read_time = tps65910_rtc_read_time,
	.set_time = tps65910_rtc_set_time,
	.read_alarm = tps65910_rtc_read_alarm,
	.set_alarm = tps65910_rtc_set_alarm,
	.alarm_irq_enable = tps65910_rtc_alarm_irq_enable,
	.read_offset = tps65910_read_offset,
	.set_offset = tps65910_set_offset,
	};

	static int tps65910_rtc_probe(struct platform_device *pdev)
	{
	struct tps65910 *tps65910 = NULL;
	struct tps65910_rtc *tps_rtc = NULL;
	int ret;
	int irq;
	u32 rtc_reg;

	tps65910 = dev_get_drvdata(pdev->dev.parent);

	tps_rtc = devm_kzalloc(&pdev->dev, sizeof(struct tps65910_rtc),
	GFP_KERNEL);
	if (!tps_rtc)
	return -ENOMEM;

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

	/* Clear pending interrupts */
	ret = regmap_read(tps65910->regmap, TPS65910_RTC_STATUS, &rtc_reg);
	if (ret < 0)
	return ret;

	ret = regmap_write(tps65910->regmap, TPS65910_RTC_STATUS, rtc_reg);
	if (ret < 0)
	return ret;

	dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n");

	/* Enable RTC digital power domain */
	ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL,
	DEVCTRL_RTC_PWDN_MASK, 0 << DEVCTRL_RTC_PWDN_SHIFT);
	if (ret < 0)
	return ret;

	rtc_reg = TPS65910_RTC_CTRL_STOP_RTC;
	ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, rtc_reg);
	if (ret < 0)
	return ret;

	platform_set_drvdata(pdev, tps_rtc);

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
	dev_warn(&pdev->dev, "Wake up is not possible as irq = %d\n",
	irq);
	return -ENXIO;
	}

	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
	tps65910_rtc_interrupt, IRQF_TRIGGER_LOW,
	dev_name(&pdev->dev), &pdev->dev);
	if (ret < 0) {
	dev_err(&pdev->dev, "IRQ is not free.\n");
	return ret;
	}
	tps_rtc->irq = irq;
	device_set_wakeup_capable(&pdev->dev, 1);

	tps_rtc->rtc->ops = &tps65910_rtc_ops;
	tps_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
	tps_rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;

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

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int tps65910_rtc_suspend(struct device *dev)
	{
	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	enable_irq_wake(tps_rtc->irq);
	return 0;
	}

	static int tps65910_rtc_resume(struct device *dev)
	{
	struct tps65910_rtc *tps_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	disable_irq_wake(tps_rtc->irq);
	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(tps65910_rtc_pm_ops, tps65910_rtc_suspend,
	tps65910_rtc_resume);

	static struct platform_driver tps65910_rtc_driver = {
	.probe = tps65910_rtc_probe,
	.driver = {
	.name = "tps65910-rtc",
	.pm = &tps65910_rtc_pm_ops,
	},
	};

	module_platform_driver(tps65910_rtc_driver);
	MODULE_ALIAS("platform:rtc-tps65910");
	MODULE_AUTHOR("Venu Byravarasu <vbyravarasu@nvidia.com>");
	MODULE_LICENSE("GPL");