drivers/rtc/rtc-rk808.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * RTC driver for Rockchip RK808
  *
  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
  *
  * Author: Chris Zhong <zyw@rock-chips.com>
  * Author: Zhang Qing <zhangqing@rock-chips.com>
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/mfd/rk808.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>

 /* RTC_CTRL_REG bitfields */
 #define BIT_RTC_CTRL_REG_STOP_RTC_M		BIT(0)

 /* RK808 has a shadowed register for saving a "frozen" RTC time.
  * When user setting "GET_TIME" to 1, the time will save in this shadowed
  * register. If set "READSEL" to 1, user read rtc time register, actually
  * get the time of that moment. If we need the real time, clr this bit.
  */
 #define BIT_RTC_CTRL_REG_RTC_GET_TIME		BIT(6)
 #define BIT_RTC_CTRL_REG_RTC_READSEL_M		BIT(7)
 #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M	BIT(3)
 #define RTC_STATUS_MASK		0xFE

 #define SECONDS_REG_MSK		0x7F
 #define MINUTES_REG_MAK		0x7F
 #define HOURS_REG_MSK		0x3F
 #define DAYS_REG_MSK		0x3F
 #define MONTHS_REG_MSK		0x1F
 #define YEARS_REG_MSK		0xFF
 #define WEEKS_REG_MSK		0x7

 /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */

 #define NUM_TIME_REGS	(RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
 #define NUM_ALARM_REGS	(RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)

 struct rk808_rtc {
 	struct rk808 *rk808;
 	struct rtc_device *rtc;
 	int irq;
 };

 /*
  * The Rockchip calendar used by the RK808 counts November with 31 days. We use
  * these translation functions to convert its dates to/from the Gregorian
  * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
  * as the day when both calendars were in sync, and treat all other dates
  * relative to that.
  * NOTE: Other system software (e.g. firmware) that reads the same hardware must
  * implement this exact same conversion algorithm, with the same anchor date.
  */
 static time64_t nov2dec_transitions(struct rtc_time *tm)
 {
 	return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
 }

 static void rockchip_to_gregorian(struct rtc_time *tm)
 {
 	/* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
 	time64_t time = rtc_tm_to_time64(tm);
 	rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
 }

 static void gregorian_to_rockchip(struct rtc_time *tm)
 {
 	time64_t extra_days = nov2dec_transitions(tm);
 	time64_t time = rtc_tm_to_time64(tm);
 	rtc_time64_to_tm(time - extra_days * 86400, tm);

 	/* Compensate if we went back over Nov 31st (will work up to 2381) */
 	if (nov2dec_transitions(tm) < extra_days) {
 		if (tm->tm_mon + 1 == 11)
 			tm->tm_mday++;	/* This may result in 31! */
 		else
 			rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
 	}
 }

 /* Read current time and date in RTC */
 static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	u8 rtc_data[NUM_TIME_REGS];
 	int ret;

 	/* Force an update of the shadowed registers right now */
 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 				 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 				 BIT_RTC_CTRL_REG_RTC_GET_TIME);
 	if (ret) {
 		dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 		return ret;
 	}

 	/*
 	 * After we set the GET_TIME bit, the rtc time can't be read
 	 * immediately. So we should wait up to 31.25 us, about one cycle of
 	 * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
 	 * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
 	 */
 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 				 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 				 0);
 	if (ret) {
 		dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 		return ret;
 	}

 	ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
 			       rtc_data, NUM_TIME_REGS);
 	if (ret) {
 		dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
 		return ret;
 	}

 	tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
 	tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
 	tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
 	tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
 	tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
 	tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
 	tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
 	rockchip_to_gregorian(tm);
 	dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);

 	return ret;
 }

 /* Set current time and date in RTC */
 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	u8 rtc_data[NUM_TIME_REGS];
 	int ret;

 	dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 	gregorian_to_rockchip(tm);
 	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);
 	rtc_data[6] = bin2bcd(tm->tm_wday);

 	/* Stop RTC while updating the RTC registers */
 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 				 BIT_RTC_CTRL_REG_STOP_RTC_M,
 				 BIT_RTC_CTRL_REG_STOP_RTC_M);
 	if (ret) {
 		dev_err(dev, "Failed to update RTC control: %d\n", ret);
 		return ret;
 	}

 	ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
 				rtc_data, NUM_TIME_REGS);
 	if (ret) {
 		dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 		return ret;
 	}
 	/* Start RTC again */
 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 				 BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 	if (ret) {
 		dev_err(dev, "Failed to update RTC control: %d\n", ret);
 		return ret;
 	}
 	return 0;
 }

 /* Read alarm time and date in RTC */
 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	u8 alrm_data[NUM_ALARM_REGS];
 	uint32_t int_reg;
 	int ret;

 	ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
 			       alrm_data, NUM_ALARM_REGS);

 	alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 	alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 	alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 	alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 	alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 	alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 	rockchip_to_gregorian(&alrm->time);

 	ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
 	if (ret) {
 		dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 		return ret;
 	}

 	dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
 		&alrm->time, alrm->time.tm_wday, &alrm->time);

 	alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;

 	return 0;
 }

 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
 {
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	int ret;

 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
 				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);

 	return ret;
 }

 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
 {
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	int ret;

 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
 				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
 				 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);

 	return ret;
 }

 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	u8 alrm_data[NUM_ALARM_REGS];
 	int ret;

 	ret = rk808_rtc_stop_alarm(rk808_rtc);
 	if (ret) {
 		dev_err(dev, "Failed to stop alarm: %d\n", ret);
 		return ret;
 	}
 	dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
 		&alrm->time, alrm->time.tm_wday, &alrm->time);

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

 	ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
 				alrm_data, NUM_ALARM_REGS);
 	if (ret) {
 		dev_err(dev, "Failed to bulk write: %d\n", ret);
 		return ret;
 	}
 	if (alrm->enabled) {
 		ret = rk808_rtc_start_alarm(rk808_rtc);
 		if (ret) {
 			dev_err(dev, "Failed to start alarm: %d\n", ret);
 			return ret;
 		}
 	}
 	return 0;
 }

 static int rk808_rtc_alarm_irq_enable(struct device *dev,
 				      unsigned int enabled)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

 	if (enabled)
 		return rk808_rtc_start_alarm(rk808_rtc);

 	return rk808_rtc_stop_alarm(rk808_rtc);
 }

 /*
  * We will just handle setting the frequency and make use the framework for
  * reading the periodic interupts.
  *
  * @freq: Current periodic IRQ freq:
  * bit 0: every second
  * bit 1: every minute
  * bit 2: every hour
  * bit 3: every day
  */
 static irqreturn_t rk808_alarm_irq(int irq, void *data)
 {
 	struct rk808_rtc *rk808_rtc = data;
 	struct rk808 *rk808 = rk808_rtc->rk808;
 	struct i2c_client *client = rk808->i2c;
 	int ret;

 	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 			   RTC_STATUS_MASK);
 	if (ret) {
 		dev_err(&client->dev,
 			"%s:Failed to update RTC status: %d\n", __func__, ret);
 		return ret;
 	}

 	rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 	dev_dbg(&client->dev,
 		 "%s:irq=%d\n", __func__, irq);
 	return IRQ_HANDLED;
 }

 static const struct rtc_class_ops rk808_rtc_ops = {
 	.read_time = rk808_rtc_readtime,
 	.set_time = rk808_rtc_set_time,
 	.read_alarm = rk808_rtc_readalarm,
 	.set_alarm = rk808_rtc_setalarm,
 	.alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 };

 #ifdef CONFIG_PM_SLEEP
 /* Turn off the alarm if it should not be a wake source. */
 static int rk808_rtc_suspend(struct device *dev)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		enable_irq_wake(rk808_rtc->irq);

 	return 0;
 }

 /* Enable the alarm if it should be enabled (in case it was disabled to
  * prevent use as a wake source).
  */
 static int rk808_rtc_resume(struct device *dev)
 {
 	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

 	if (device_may_wakeup(dev))
 		disable_irq_wake(rk808_rtc->irq);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 	rk808_rtc_suspend, rk808_rtc_resume);

 static int rk808_rtc_probe(struct platform_device *pdev)
 {
 	struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 	struct rk808_rtc *rk808_rtc;
 	int ret;

 	rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 	if (rk808_rtc == NULL)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, rk808_rtc);
 	rk808_rtc->rk808 = rk808;

 	/* start rtc running by default, and use shadowed timer. */
 	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 				 BIT_RTC_CTRL_REG_STOP_RTC_M |
 				 BIT_RTC_CTRL_REG_RTC_READSEL_M,
 				 BIT_RTC_CTRL_REG_RTC_READSEL_M);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Failed to update RTC control: %d\n", ret);
 		return ret;
 	}

 	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 			   RTC_STATUS_MASK);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Failed to write RTC status: %d\n", ret);
 		return ret;
 	}

 	device_init_wakeup(&pdev->dev, 1);

 	rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rk808_rtc->rtc))
 		return PTR_ERR(rk808_rtc->rtc);

 	rk808_rtc->rtc->ops = &rk808_rtc_ops;

 	rk808_rtc->irq = platform_get_irq(pdev, 0);
 	if (rk808_rtc->irq < 0) {
 		if (rk808_rtc->irq != -EPROBE_DEFER)
 			dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
 				rk808_rtc->irq);
 		return rk808_rtc->irq;
 	}

 	/* request alarm irq of rk808 */
 	ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 					rk808_alarm_irq, 0,
 					"RTC alarm", rk808_rtc);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 			rk808_rtc->irq, ret);
 		return ret;
 	}

 	return rtc_register_device(rk808_rtc->rtc);
 }

 static struct platform_driver rk808_rtc_driver = {
 	.probe = rk808_rtc_probe,
 	.driver = {
 		.name = "rk808-rtc",
 		.pm = &rk808_rtc_pm_ops,
 	},
 };

 module_platform_driver(rk808_rtc_driver);

 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:rk808-rtc");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* RTC driver for Rockchip RK808
	*
	* Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
	*
	* Author: Chris Zhong <zyw@rock-chips.com>
	* Author: Zhang Qing <zhangqing@rock-chips.com>
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/rtc.h>
	#include <linux/bcd.h>
	#include <linux/mfd/rk808.h>
	#include <linux/platform_device.h>
	#include <linux/i2c.h>

	/* RTC_CTRL_REG bitfields */
	#define BIT_RTC_CTRL_REG_STOP_RTC_M BIT(0)

	/* RK808 has a shadowed register for saving a "frozen" RTC time.
	* When user setting "GET_TIME" to 1, the time will save in this shadowed
	* register. If set "READSEL" to 1, user read rtc time register, actually
	* get the time of that moment. If we need the real time, clr this bit.
	*/
	#define BIT_RTC_CTRL_REG_RTC_GET_TIME BIT(6)
	#define BIT_RTC_CTRL_REG_RTC_READSEL_M BIT(7)
	#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M BIT(3)
	#define RTC_STATUS_MASK 0xFE

	#define SECONDS_REG_MSK 0x7F
	#define MINUTES_REG_MAK 0x7F
	#define HOURS_REG_MSK 0x3F
	#define DAYS_REG_MSK 0x3F
	#define MONTHS_REG_MSK 0x1F
	#define YEARS_REG_MSK 0xFF
	#define WEEKS_REG_MSK 0x7

	/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */

	#define NUM_TIME_REGS (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
	#define NUM_ALARM_REGS (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)

	struct rk808_rtc {
	struct rk808 *rk808;
	struct rtc_device *rtc;
	int irq;
	};

	/*
	* The Rockchip calendar used by the RK808 counts November with 31 days. We use
	* these translation functions to convert its dates to/from the Gregorian
	* calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
	* as the day when both calendars were in sync, and treat all other dates
	* relative to that.
	* NOTE: Other system software (e.g. firmware) that reads the same hardware must
	* implement this exact same conversion algorithm, with the same anchor date.
	*/
	static time64_t nov2dec_transitions(struct rtc_time *tm)
	{
	return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
	}

	static void rockchip_to_gregorian(struct rtc_time *tm)
	{
	/* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
	time64_t time = rtc_tm_to_time64(tm);
	rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
	}

	static void gregorian_to_rockchip(struct rtc_time *tm)
	{
	time64_t extra_days = nov2dec_transitions(tm);
	time64_t time = rtc_tm_to_time64(tm);
	rtc_time64_to_tm(time - extra_days * 86400, tm);

	/* Compensate if we went back over Nov 31st (will work up to 2381) */
	if (nov2dec_transitions(tm) < extra_days) {
	if (tm->tm_mon + 1 == 11)
	tm->tm_mday++; /* This may result in 31! */
	else
	rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
	}
	}

	/* Read current time and date in RTC */
	static int rk808_rtc_readtime(struct device dev, struct rtc_time tm)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
	struct rk808 *rk808 = rk808_rtc->rk808;
	u8 rtc_data[NUM_TIME_REGS];
	int ret;

	/* Force an update of the shadowed registers right now */
	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
	BIT_RTC_CTRL_REG_RTC_GET_TIME,
	BIT_RTC_CTRL_REG_RTC_GET_TIME);
	if (ret) {
	dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
	return ret;
	}

	/*
	* After we set the GET_TIME bit, the rtc time can't be read
	* immediately. So we should wait up to 31.25 us, about one cycle of
	* 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
	* certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
	*/
	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
	BIT_RTC_CTRL_REG_RTC_GET_TIME,
	0);
	if (ret) {
	dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
	return ret;
	}

	ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
	rtc_data, NUM_TIME_REGS);
	if (ret) {
	dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
	return ret;
	}

	tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
	tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
	tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
	tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
	tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
	tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
	tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
	rockchip_to_gregorian(tm);
	dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);

	return ret;
	}

	/* Set current time and date in RTC */
	static int rk808_rtc_set_time(struct device dev, struct rtc_time tm)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
	struct rk808 *rk808 = rk808_rtc->rk808;
	u8 rtc_data[NUM_TIME_REGS];
	int ret;

	dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
	gregorian_to_rockchip(tm);
	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);
	rtc_data[6] = bin2bcd(tm->tm_wday);

	/* Stop RTC while updating the RTC registers */
	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
	BIT_RTC_CTRL_REG_STOP_RTC_M,
	BIT_RTC_CTRL_REG_STOP_RTC_M);
	if (ret) {
	dev_err(dev, "Failed to update RTC control: %d\n", ret);
	return ret;
	}

	ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
	rtc_data, NUM_TIME_REGS);
	if (ret) {
	dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
	return ret;
	}
	/* Start RTC again */
	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
	BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
	if (ret) {
	dev_err(dev, "Failed to update RTC control: %d\n", ret);
	return ret;
	}
	return 0;
	}

	/* Read alarm time and date in RTC */
	static int rk808_rtc_readalarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
	struct rk808 *rk808 = rk808_rtc->rk808;
	u8 alrm_data[NUM_ALARM_REGS];
	uint32_t int_reg;
	int ret;

	ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
	alrm_data, NUM_ALARM_REGS);

	alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
	alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
	alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
	alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
	alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
	alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
	rockchip_to_gregorian(&alrm->time);

	ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
	if (ret) {
	dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
	return ret;
	}

	dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
	&alrm->time, alrm->time.tm_wday, &alrm->time);

	alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;

	return 0;
	}

	static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
	{
	struct rk808 *rk808 = rk808_rtc->rk808;
	int ret;

	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
	BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);

	return ret;
	}

	static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
	{
	struct rk808 *rk808 = rk808_rtc->rk808;
	int ret;

	ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
	BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
	BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);

	return ret;
	}

	static int rk808_rtc_setalarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
	struct rk808 *rk808 = rk808_rtc->rk808;
	u8 alrm_data[NUM_ALARM_REGS];
	int ret;

	ret = rk808_rtc_stop_alarm(rk808_rtc);
	if (ret) {
	dev_err(dev, "Failed to stop alarm: %d\n", ret);
	return ret;
	}
	dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
	&alrm->time, alrm->time.tm_wday, &alrm->time);

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

	ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
	alrm_data, NUM_ALARM_REGS);
	if (ret) {
	dev_err(dev, "Failed to bulk write: %d\n", ret);
	return ret;
	}
	if (alrm->enabled) {
	ret = rk808_rtc_start_alarm(rk808_rtc);
	if (ret) {
	dev_err(dev, "Failed to start alarm: %d\n", ret);
	return ret;
	}
	}
	return 0;
	}

	static int rk808_rtc_alarm_irq_enable(struct device *dev,
	unsigned int enabled)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

	if (enabled)
	return rk808_rtc_start_alarm(rk808_rtc);

	return rk808_rtc_stop_alarm(rk808_rtc);
	}

	/*
	* We will just handle setting the frequency and make use the framework for
	* reading the periodic interupts.
	*
	* @freq: Current periodic IRQ freq:
	* bit 0: every second
	* bit 1: every minute
	* bit 2: every hour
	* bit 3: every day
	*/
	static irqreturn_t rk808_alarm_irq(int irq, void *data)
	{
	struct rk808_rtc *rk808_rtc = data;
	struct rk808 *rk808 = rk808_rtc->rk808;
	struct i2c_client *client = rk808->i2c;
	int ret;

	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
	RTC_STATUS_MASK);
	if (ret) {
	dev_err(&client->dev,
	"%s:Failed to update RTC status: %d\n", __func__, ret);
	return ret;
	}

	rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF \| RTC_AF);
	dev_dbg(&client->dev,
	"%s:irq=%d\n", __func__, irq);
	return IRQ_HANDLED;
	}

	static const struct rtc_class_ops rk808_rtc_ops = {
	.read_time = rk808_rtc_readtime,
	.set_time = rk808_rtc_set_time,
	.read_alarm = rk808_rtc_readalarm,
	.set_alarm = rk808_rtc_setalarm,
	.alarm_irq_enable = rk808_rtc_alarm_irq_enable,
	};

	#ifdef CONFIG_PM_SLEEP
	/* Turn off the alarm if it should not be a wake source. */
	static int rk808_rtc_suspend(struct device *dev)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	enable_irq_wake(rk808_rtc->irq);

	return 0;
	}

	/* Enable the alarm if it should be enabled (in case it was disabled to
	* prevent use as a wake source).
	*/
	static int rk808_rtc_resume(struct device *dev)
	{
	struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
	disable_irq_wake(rk808_rtc->irq);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
	rk808_rtc_suspend, rk808_rtc_resume);

	static int rk808_rtc_probe(struct platform_device *pdev)
	{
	struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
	struct rk808_rtc *rk808_rtc;
	int ret;

	rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
	if (rk808_rtc == NULL)
	return -ENOMEM;

	platform_set_drvdata(pdev, rk808_rtc);
	rk808_rtc->rk808 = rk808;

	/* start rtc running by default, and use shadowed timer. */
	ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
	BIT_RTC_CTRL_REG_STOP_RTC_M \|
	BIT_RTC_CTRL_REG_RTC_READSEL_M,
	BIT_RTC_CTRL_REG_RTC_READSEL_M);
	if (ret) {
	dev_err(&pdev->dev,
	"Failed to update RTC control: %d\n", ret);
	return ret;
	}

	ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
	RTC_STATUS_MASK);
	if (ret) {
	dev_err(&pdev->dev,
	"Failed to write RTC status: %d\n", ret);
	return ret;
	}

	device_init_wakeup(&pdev->dev, 1);

	rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rk808_rtc->rtc))
	return PTR_ERR(rk808_rtc->rtc);

	rk808_rtc->rtc->ops = &rk808_rtc_ops;

	rk808_rtc->irq = platform_get_irq(pdev, 0);
	if (rk808_rtc->irq < 0) {
	if (rk808_rtc->irq != -EPROBE_DEFER)
	dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
	rk808_rtc->irq);
	return rk808_rtc->irq;
	}

	/* request alarm irq of rk808 */
	ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
	rk808_alarm_irq, 0,
	"RTC alarm", rk808_rtc);
	if (ret) {
	dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
	rk808_rtc->irq, ret);
	return ret;
	}

	return rtc_register_device(rk808_rtc->rtc);
	}

	static struct platform_driver rk808_rtc_driver = {
	.probe = rk808_rtc_probe,
	.driver = {
	.name = "rk808-rtc",
	.pm = &rk808_rtc_pm_ops,
	},
	};

	module_platform_driver(rk808_rtc_driver);

	MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
	MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
	MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:rk808-rtc");