// SPDX-License-Identifier: GPL-2.0-only

  /* drivers/rtc/rtc-s3c.c
   *

   * Copyright (c) 2010 Samsung Electronics Co., Ltd.
   *		http://www.samsung.com/
   *

   * Copyright (c) 2004,2006 Simtec Electronics
   *	Ben Dooks, <ben@simtec.co.uk>
   *	http://armlinux.simtec.co.uk/
   *

   * S3C2410/S3C2440/S3C24XX Internal RTC Driver
  */
  
  #include <linux/module.h>
  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/interrupt.h>
  #include <linux/rtc.h>
  #include <linux/bcd.h>
  #include <linux/clk.h>

  #include <linux/log2.h>

  #include <linux/slab.h>

  #include <linux/of.h>

  #include <linux/of_device.h>

  #include <linux/uaccess.h>
  #include <linux/io.h>

  #include <asm/irq.h>

  #include "rtc-s3c.h"

  struct s3c_rtc {
  	struct device *dev;
  	struct rtc_device *rtc;
  
  	void __iomem *base;
  	struct clk *rtc_clk;

  	struct clk *rtc_src_clk;

  	bool alarm_enabled;

  	const struct s3c_rtc_data *data;

  	int irq_alarm;
  	int irq_tick;

  	spinlock_t pie_lock;

  	spinlock_t alarm_lock;

  	int ticnt_save;
  	int ticnt_en_save;

  	bool wake_en;
  };

  struct s3c_rtc_data {
  	int max_user_freq;

  	bool needs_src_clk;

  
  	void (*irq_handler) (struct s3c_rtc *info, int mask);
  	void (*set_freq) (struct s3c_rtc *info, int freq);
  	void (*enable_tick) (struct s3c_rtc *info, struct seq_file *seq);
  	void (*select_tick_clk) (struct s3c_rtc *info);
  	void (*save_tick_cnt) (struct s3c_rtc *info);
  	void (*restore_tick_cnt) (struct s3c_rtc *info);
  	void (*enable) (struct s3c_rtc *info);
  	void (*disable) (struct s3c_rtc *info);
  };

  static int s3c_rtc_enable_clk(struct s3c_rtc *info)

  {

  	int ret;

  	ret = clk_enable(info->rtc_clk);
  	if (ret)
  		return ret;

  	if (info->data->needs_src_clk) {
  		ret = clk_enable(info->rtc_src_clk);
  		if (ret) {
  			clk_disable(info->rtc_clk);
  			return ret;

  		}

  	}

  	return 0;

  }
  
  static void s3c_rtc_disable_clk(struct s3c_rtc *info)
  {

  	if (info->data->needs_src_clk)
  		clk_disable(info->rtc_src_clk);
  	clk_disable(info->rtc_clk);

  }

  /* IRQ Handlers */

  static irqreturn_t s3c_rtc_tickirq(int irq, void *id)

  {

  	struct s3c_rtc *info = (struct s3c_rtc *)id;

  	if (info->data->irq_handler)
  		info->data->irq_handler(info, S3C2410_INTP_TIC);

  	return IRQ_HANDLED;
  }

  static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)

  {

  	struct s3c_rtc *info = (struct s3c_rtc *)id;

  	if (info->data->irq_handler)
  		info->data->irq_handler(info, S3C2410_INTP_ALM);

  	return IRQ_HANDLED;
  }
  
  /* Update control registers */

  static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)

  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	unsigned long flags;

  	unsigned int tmp;

  	int ret;

  	dev_dbg(info->dev, "%s: aie=%d
  ", __func__, enabled);

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;

  	if (enabled)

  		tmp |= S3C2410_RTCALM_ALMEN;

  	writeb(tmp, info->base + S3C2410_RTCALM);

  	spin_lock_irqsave(&info->alarm_lock, flags);

  	if (info->alarm_enabled && !enabled)

  		s3c_rtc_disable_clk(info);

  	else if (!info->alarm_enabled && enabled)
  		ret = s3c_rtc_enable_clk(info);

  	info->alarm_enabled = enabled;
  	spin_unlock_irqrestore(&info->alarm_lock, flags);
  
  	s3c_rtc_disable_clk(info);
  
  	return ret;

  }

  /* Set RTC frequency */

  static int s3c_rtc_setfreq(struct s3c_rtc *info, int freq)

  {

  	int ret;

  	if (!is_power_of_2(freq))
  		return -EINVAL;

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	spin_lock_irq(&info->pie_lock);

  	if (info->data->set_freq)
  		info->data->set_freq(info, freq);

  	spin_unlock_irq(&info->pie_lock);

  	s3c_rtc_disable_clk(info);

  
  	return 0;

  }
  
  /* Time read/write */

  static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	unsigned int have_retried = 0;

  	int ret;

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  retry_get_time:

  	rtc_tm->tm_min  = readb(info->base + S3C2410_RTCMIN);
  	rtc_tm->tm_hour = readb(info->base + S3C2410_RTCHOUR);
  	rtc_tm->tm_mday = readb(info->base + S3C2410_RTCDATE);
  	rtc_tm->tm_mon  = readb(info->base + S3C2410_RTCMON);
  	rtc_tm->tm_year = readb(info->base + S3C2410_RTCYEAR);
  	rtc_tm->tm_sec  = readb(info->base + S3C2410_RTCSEC);

  	/* the only way to work out whether the system was mid-update

  	 * when we read it is to check the second counter, and if it
  	 * is zero, then we re-try the entire read
  	 */
  
  	if (rtc_tm->tm_sec == 0 && !have_retried) {
  		have_retried = 1;
  		goto retry_get_time;
  	}

  	rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
  	rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
  	rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
  	rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
  	rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
  	rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);

  	s3c_rtc_disable_clk(info);

  	rtc_tm->tm_year += 100;
  	rtc_tm->tm_mon -= 1;

  	dev_dbg(dev, "read time %ptR
  ", rtc_tm);

  	return 0;

  }
  
  static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	int year = tm->tm_year - 100;

  	int ret;

  	dev_dbg(dev, "set time %ptR
  ", tm);

  
  	/* we get around y2k by simply not supporting it */

  	if (year < 0 || year >= 100) {

  		dev_err(dev, "rtc only supports 100 years
  ");

  		return -EINVAL;

  	}

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  
  	writeb(bin2bcd(tm->tm_sec),  info->base + S3C2410_RTCSEC);
  	writeb(bin2bcd(tm->tm_min),  info->base + S3C2410_RTCMIN);
  	writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_RTCHOUR);
  	writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_RTCDATE);
  	writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_RTCMON);
  	writeb(bin2bcd(year), info->base + S3C2410_RTCYEAR);

  	s3c_rtc_disable_clk(info);

  
  	return 0;
  }
  
  static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	struct rtc_time *alm_tm = &alrm->time;
  	unsigned int alm_en;

  	int ret;

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	alm_tm->tm_sec  = readb(info->base + S3C2410_ALMSEC);
  	alm_tm->tm_min  = readb(info->base + S3C2410_ALMMIN);
  	alm_tm->tm_hour = readb(info->base + S3C2410_ALMHOUR);
  	alm_tm->tm_mon  = readb(info->base + S3C2410_ALMMON);
  	alm_tm->tm_mday = readb(info->base + S3C2410_ALMDATE);
  	alm_tm->tm_year = readb(info->base + S3C2410_ALMYEAR);

  	alm_en = readb(info->base + S3C2410_RTCALM);

  	s3c_rtc_disable_clk(info);

  	alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;

  	dev_dbg(dev, "read alarm %d, %ptR
  ", alm_en, alm_tm);

  	/* decode the alarm enable field */

  	if (alm_en & S3C2410_RTCALM_SECEN)

  		alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);

  
  	if (alm_en & S3C2410_RTCALM_MINEN)

  		alm_tm->tm_min = bcd2bin(alm_tm->tm_min);

  
  	if (alm_en & S3C2410_RTCALM_HOUREN)

  		alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);

  
  	if (alm_en & S3C2410_RTCALM_DAYEN)

  		alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);

  
  	if (alm_en & S3C2410_RTCALM_MONEN) {

  		alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);

  		alm_tm->tm_mon -= 1;

  	}
  
  	if (alm_en & S3C2410_RTCALM_YEAREN)

  		alm_tm->tm_year = bcd2bin(alm_tm->tm_year);

  
  	return 0;
  }
  
  static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	struct rtc_time *tm = &alrm->time;
  	unsigned int alrm_en;

  	int ret;

  	dev_dbg(dev, "s3c_rtc_setalarm: %d, %ptR
  ", alrm->enabled, tm);

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
  	writeb(0x00, info->base + S3C2410_RTCALM);

  
  	if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
  		alrm_en |= S3C2410_RTCALM_SECEN;

  		writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_ALMSEC);

  	}
  
  	if (tm->tm_min < 60 && tm->tm_min >= 0) {
  		alrm_en |= S3C2410_RTCALM_MINEN;

  		writeb(bin2bcd(tm->tm_min), info->base + S3C2410_ALMMIN);

  	}
  
  	if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
  		alrm_en |= S3C2410_RTCALM_HOUREN;

  		writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_ALMHOUR);

  	}

  	if (tm->tm_mon < 12 && tm->tm_mon >= 0) {
  		alrm_en |= S3C2410_RTCALM_MONEN;
  		writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_ALMMON);
  	}
  
  	if (tm->tm_mday <= 31 && tm->tm_mday >= 1) {
  		alrm_en |= S3C2410_RTCALM_DAYEN;
  		writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_ALMDATE);
  	}

  	dev_dbg(dev, "setting S3C2410_RTCALM to %08x
  ", alrm_en);

  	writeb(alrm_en, info->base + S3C2410_RTCALM);

  	s3c_rtc_setaie(dev, alrm->enabled);

  	s3c_rtc_disable_clk(info);

  	return 0;
  }

  static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	int ret;

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	if (info->data->enable_tick)
  		info->data->enable_tick(info, seq);

  	s3c_rtc_disable_clk(info);

  	return 0;
  }

  static const struct rtc_class_ops s3c_rtcops = {

  	.read_time	= s3c_rtc_gettime,
  	.set_time	= s3c_rtc_settime,
  	.read_alarm	= s3c_rtc_getalarm,
  	.set_alarm	= s3c_rtc_setalarm,

  	.proc		= s3c_rtc_proc,
  	.alarm_irq_enable = s3c_rtc_setaie,

  };

  static void s3c24xx_rtc_enable(struct s3c_rtc *info)

  {

  	unsigned int con, tmp;

  	con = readw(info->base + S3C2410_RTCCON);

  	/* re-enable the device, and check it is ok */
  	if ((con & S3C2410_RTCCON_RTCEN) == 0) {
  		dev_info(info->dev, "rtc disabled, re-enabling
  ");

  		tmp = readw(info->base + S3C2410_RTCCON);

  		writew(tmp | S3C2410_RTCCON_RTCEN, info->base + S3C2410_RTCCON);

  	}

  	if (con & S3C2410_RTCCON_CNTSEL) {
  		dev_info(info->dev, "removing RTCCON_CNTSEL
  ");

  		tmp = readw(info->base + S3C2410_RTCCON);
  		writew(tmp & ~S3C2410_RTCCON_CNTSEL,

  		       info->base + S3C2410_RTCCON);

  	}

  	if (con & S3C2410_RTCCON_CLKRST) {
  		dev_info(info->dev, "removing RTCCON_CLKRST
  ");

  		tmp = readw(info->base + S3C2410_RTCCON);
  		writew(tmp & ~S3C2410_RTCCON_CLKRST,

  		       info->base + S3C2410_RTCCON);

  	}

  }
  
  static void s3c24xx_rtc_disable(struct s3c_rtc *info)
  {
  	unsigned int con;

  	con = readw(info->base + S3C2410_RTCCON);
  	con &= ~S3C2410_RTCCON_RTCEN;
  	writew(con, info->base + S3C2410_RTCCON);
  
  	con = readb(info->base + S3C2410_TICNT);
  	con &= ~S3C2410_TICNT_ENABLE;
  	writeb(con, info->base + S3C2410_TICNT);

  }
  
  static void s3c6410_rtc_disable(struct s3c_rtc *info)
  {
  	unsigned int con;

  	con = readw(info->base + S3C2410_RTCCON);
  	con &= ~S3C64XX_RTCCON_TICEN;
  	con &= ~S3C2410_RTCCON_RTCEN;
  	writew(con, info->base + S3C2410_RTCCON);

  }

  static int s3c_rtc_remove(struct platform_device *pdev)

  {

  	struct s3c_rtc *info = platform_get_drvdata(pdev);
  
  	s3c_rtc_setaie(info->dev, 0);

  	if (info->data->needs_src_clk)
  		clk_unprepare(info->rtc_src_clk);

  	clk_unprepare(info->rtc_clk);

  	return 0;
  }

  static int s3c_rtc_probe(struct platform_device *pdev)

  {

  	struct s3c_rtc *info = NULL;

  	struct rtc_time rtc_tm;

  	struct resource *res;
  	int ret;

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

  
  	/* find the IRQs */

  	info->irq_tick = platform_get_irq(pdev, 1);
  	if (info->irq_tick < 0) {

  		dev_err(&pdev->dev, "no irq for rtc tick
  ");

  		return info->irq_tick;

  	}

  	info->dev = &pdev->dev;

  	info->data = of_device_get_match_data(&pdev->dev);

  	if (!info->data) {
  		dev_err(&pdev->dev, "failed getting s3c_rtc_data
  ");
  		return -EINVAL;
  	}

  	spin_lock_init(&info->pie_lock);

  	spin_lock_init(&info->alarm_lock);

  
  	platform_set_drvdata(pdev, info);
  
  	info->irq_alarm = platform_get_irq(pdev, 0);
  	if (info->irq_alarm < 0) {

  		dev_err(&pdev->dev, "no irq for alarm
  ");

  		return info->irq_alarm;

  	}

  	dev_dbg(&pdev->dev, "s3c2410_rtc: tick irq %d, alarm irq %d
  ",

  		info->irq_tick, info->irq_alarm);

  
  	/* get the memory region */

  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

  	info->base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(info->base))
  		return PTR_ERR(info->base);

  	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
  	if (IS_ERR(info->rtc_clk)) {

  		ret = PTR_ERR(info->rtc_clk);
  		if (ret != -EPROBE_DEFER)
  			dev_err(&pdev->dev, "failed to find rtc clock
  ");
  		else
  			dev_dbg(&pdev->dev, "probe deferred due to missing rtc clk
  ");
  		return ret;

  	}

  	ret = clk_prepare_enable(info->rtc_clk);
  	if (ret)
  		return ret;

  	if (info->data->needs_src_clk) {
  		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
  		if (IS_ERR(info->rtc_src_clk)) {

  			ret = PTR_ERR(info->rtc_src_clk);
  			if (ret != -EPROBE_DEFER)
  				dev_err(&pdev->dev,
  					"failed to find rtc source clock
  ");
  			else
  				dev_dbg(&pdev->dev,
  					"probe deferred due to missing rtc src clk
  ");

  			goto err_src_clk;

  		}

  		ret = clk_prepare_enable(info->rtc_src_clk);
  		if (ret)
  			goto err_src_clk;

  	}

  	/* check to see if everything is setup correctly */

  	if (info->data->enable)
  		info->data->enable(info);

  	dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x
  ",

  		readw(info->base + S3C2410_RTCCON));

  	device_init_wakeup(&pdev->dev, 1);

  	/* Check RTC Time */

  	if (s3c_rtc_gettime(&pdev->dev, &rtc_tm)) {

  		rtc_tm.tm_year	= 100;
  		rtc_tm.tm_mon	= 0;
  		rtc_tm.tm_mday	= 1;
  		rtc_tm.tm_hour	= 0;
  		rtc_tm.tm_min	= 0;
  		rtc_tm.tm_sec	= 0;
  
  		s3c_rtc_settime(&pdev->dev, &rtc_tm);
  
  		dev_warn(&pdev->dev, "warning: invalid RTC value so initializing it
  ");
  	}

  	/* register RTC and exit */

  	info->rtc = devm_rtc_device_register(&pdev->dev, "s3c", &s3c_rtcops,

  					     THIS_MODULE);

  	if (IS_ERR(info->rtc)) {

  		dev_err(&pdev->dev, "cannot attach rtc
  ");

  		ret = PTR_ERR(info->rtc);

  		goto err_nortc;
  	}

  	ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,

  			       0, "s3c2410-rtc alarm", info);

  	if (ret) {
  		dev_err(&pdev->dev, "IRQ%d error %d
  ", info->irq_alarm, ret);
  		goto err_nortc;
  	}

  	ret = devm_request_irq(&pdev->dev, info->irq_tick, s3c_rtc_tickirq,

  			       0, "s3c2410-rtc tick", info);

  	if (ret) {
  		dev_err(&pdev->dev, "IRQ%d error %d
  ", info->irq_tick, ret);
  		goto err_nortc;
  	}

  	if (info->data->select_tick_clk)
  		info->data->select_tick_clk(info);

  	s3c_rtc_setfreq(info, 1);

  	s3c_rtc_disable_clk(info);

  	return 0;

  err_nortc:

  	if (info->data->disable)
  		info->data->disable(info);

  
  	if (info->data->needs_src_clk)
  		clk_disable_unprepare(info->rtc_src_clk);

  err_src_clk:

  	clk_disable_unprepare(info->rtc_clk);

  	return ret;
  }

  #ifdef CONFIG_PM_SLEEP

  static int s3c_rtc_suspend(struct device *dev)

  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	int ret;

  	ret = s3c_rtc_enable_clk(info);
  	if (ret)
  		return ret;

  	/* save TICNT for anyone using periodic interrupts */

  	if (info->data->save_tick_cnt)
  		info->data->save_tick_cnt(info);
  
  	if (info->data->disable)
  		info->data->disable(info);

  	if (device_may_wakeup(dev) && !info->wake_en) {
  		if (enable_irq_wake(info->irq_alarm) == 0)
  			info->wake_en = true;

  		else

  			dev_err(dev, "enable_irq_wake failed
  ");

  	}

  	return 0;
  }

  static int s3c_rtc_resume(struct device *dev)

  {

  	struct s3c_rtc *info = dev_get_drvdata(dev);

  	if (info->data->enable)
  		info->data->enable(info);
  
  	if (info->data->restore_tick_cnt)
  		info->data->restore_tick_cnt(info);

  	s3c_rtc_disable_clk(info);

  	if (device_may_wakeup(dev) && info->wake_en) {
  		disable_irq_wake(info->irq_alarm);
  		info->wake_en = false;

  	}

  	return 0;
  }

  #endif

  static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);

  static void s3c24xx_rtc_irq(struct s3c_rtc *info, int mask)
  {

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

  }
  
  static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
  {

  	rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
  	writeb(mask, info->base + S3C2410_INTP);

  }
  
  static void s3c2410_rtc_setfreq(struct s3c_rtc *info, int freq)
  {
  	unsigned int tmp = 0;
  	int val;
  
  	tmp = readb(info->base + S3C2410_TICNT);
  	tmp &= S3C2410_TICNT_ENABLE;
  
  	val = (info->rtc->max_user_freq / freq) - 1;
  	tmp |= val;
  
  	writel(tmp, info->base + S3C2410_TICNT);
  }
  
  static void s3c2416_rtc_setfreq(struct s3c_rtc *info, int freq)
  {
  	unsigned int tmp = 0;
  	int val;
  
  	tmp = readb(info->base + S3C2410_TICNT);
  	tmp &= S3C2410_TICNT_ENABLE;
  
  	val = (info->rtc->max_user_freq / freq) - 1;
  
  	tmp |= S3C2443_TICNT_PART(val);
  	writel(S3C2443_TICNT1_PART(val), info->base + S3C2443_TICNT1);
  
  	writel(S3C2416_TICNT2_PART(val), info->base + S3C2416_TICNT2);
  
  	writel(tmp, info->base + S3C2410_TICNT);
  }
  
  static void s3c2443_rtc_setfreq(struct s3c_rtc *info, int freq)
  {
  	unsigned int tmp = 0;
  	int val;
  
  	tmp = readb(info->base + S3C2410_TICNT);
  	tmp &= S3C2410_TICNT_ENABLE;
  
  	val = (info->rtc->max_user_freq / freq) - 1;
  
  	tmp |= S3C2443_TICNT_PART(val);
  	writel(S3C2443_TICNT1_PART(val), info->base + S3C2443_TICNT1);
  
  	writel(tmp, info->base + S3C2410_TICNT);
  }
  
  static void s3c6410_rtc_setfreq(struct s3c_rtc *info, int freq)
  {
  	int val;
  
  	val = (info->rtc->max_user_freq / freq) - 1;
  	writel(val, info->base + S3C2410_TICNT);
  }
  
  static void s3c24xx_rtc_enable_tick(struct s3c_rtc *info, struct seq_file *seq)
  {
  	unsigned int ticnt;
  
  	ticnt = readb(info->base + S3C2410_TICNT);
  	ticnt &= S3C2410_TICNT_ENABLE;
  
  	seq_printf(seq, "periodic_IRQ\t: %s
  ", ticnt  ? "yes" : "no");
  }
  
  static void s3c2416_rtc_select_tick_clk(struct s3c_rtc *info)
  {
  	unsigned int con;
  
  	con = readw(info->base + S3C2410_RTCCON);
  	con |= S3C2443_RTCCON_TICSEL;
  	writew(con, info->base + S3C2410_RTCCON);
  }
  
  static void s3c6410_rtc_enable_tick(struct s3c_rtc *info, struct seq_file *seq)
  {
  	unsigned int ticnt;
  
  	ticnt = readw(info->base + S3C2410_RTCCON);
  	ticnt &= S3C64XX_RTCCON_TICEN;
  
  	seq_printf(seq, "periodic_IRQ\t: %s
  ", ticnt  ? "yes" : "no");
  }
  
  static void s3c24xx_rtc_save_tick_cnt(struct s3c_rtc *info)
  {
  	info->ticnt_save = readb(info->base + S3C2410_TICNT);
  }
  
  static void s3c24xx_rtc_restore_tick_cnt(struct s3c_rtc *info)
  {
  	writeb(info->ticnt_save, info->base + S3C2410_TICNT);
  }
  
  static void s3c6410_rtc_save_tick_cnt(struct s3c_rtc *info)
  {
  	info->ticnt_en_save = readw(info->base + S3C2410_RTCCON);
  	info->ticnt_en_save &= S3C64XX_RTCCON_TICEN;
  	info->ticnt_save = readl(info->base + S3C2410_TICNT);
  }
  
  static void s3c6410_rtc_restore_tick_cnt(struct s3c_rtc *info)
  {
  	unsigned int con;
  
  	writel(info->ticnt_save, info->base + S3C2410_TICNT);
  	if (info->ticnt_en_save) {
  		con = readw(info->base + S3C2410_RTCCON);

  		writew(con | info->ticnt_en_save, info->base + S3C2410_RTCCON);

  	}
  }
  
  static struct s3c_rtc_data const s3c2410_rtc_data = {
  	.max_user_freq		= 128,
  	.irq_handler		= s3c24xx_rtc_irq,
  	.set_freq		= s3c2410_rtc_setfreq,
  	.enable_tick		= s3c24xx_rtc_enable_tick,
  	.save_tick_cnt		= s3c24xx_rtc_save_tick_cnt,
  	.restore_tick_cnt	= s3c24xx_rtc_restore_tick_cnt,
  	.enable			= s3c24xx_rtc_enable,
  	.disable		= s3c24xx_rtc_disable,
  };
  
  static struct s3c_rtc_data const s3c2416_rtc_data = {
  	.max_user_freq		= 32768,
  	.irq_handler		= s3c24xx_rtc_irq,
  	.set_freq		= s3c2416_rtc_setfreq,
  	.enable_tick		= s3c24xx_rtc_enable_tick,
  	.select_tick_clk	= s3c2416_rtc_select_tick_clk,
  	.save_tick_cnt		= s3c24xx_rtc_save_tick_cnt,
  	.restore_tick_cnt	= s3c24xx_rtc_restore_tick_cnt,
  	.enable			= s3c24xx_rtc_enable,
  	.disable		= s3c24xx_rtc_disable,
  };
  
  static struct s3c_rtc_data const s3c2443_rtc_data = {
  	.max_user_freq		= 32768,
  	.irq_handler		= s3c24xx_rtc_irq,
  	.set_freq		= s3c2443_rtc_setfreq,
  	.enable_tick		= s3c24xx_rtc_enable_tick,
  	.select_tick_clk	= s3c2416_rtc_select_tick_clk,
  	.save_tick_cnt		= s3c24xx_rtc_save_tick_cnt,
  	.restore_tick_cnt	= s3c24xx_rtc_restore_tick_cnt,
  	.enable			= s3c24xx_rtc_enable,
  	.disable		= s3c24xx_rtc_disable,
  };
  
  static struct s3c_rtc_data const s3c6410_rtc_data = {
  	.max_user_freq		= 32768,

  	.needs_src_clk		= true,

  	.irq_handler		= s3c6410_rtc_irq,
  	.set_freq		= s3c6410_rtc_setfreq,
  	.enable_tick		= s3c6410_rtc_enable_tick,
  	.save_tick_cnt		= s3c6410_rtc_save_tick_cnt,
  	.restore_tick_cnt	= s3c6410_rtc_restore_tick_cnt,
  	.enable			= s3c24xx_rtc_enable,
  	.disable		= s3c6410_rtc_disable,

  };

  static const struct of_device_id s3c_rtc_dt_match[] = {

  	{

  		.compatible = "samsung,s3c2410-rtc",

  		.data = &s3c2410_rtc_data,

  	}, {

  		.compatible = "samsung,s3c2416-rtc",

  		.data = &s3c2416_rtc_data,

  	}, {

  		.compatible = "samsung,s3c2443-rtc",

  		.data = &s3c2443_rtc_data,

  	}, {

  		.compatible = "samsung,s3c6410-rtc",

  		.data = &s3c6410_rtc_data,

  	}, {
  		.compatible = "samsung,exynos3250-rtc",

  		.data = &s3c6410_rtc_data,

  	},

  	{ /* sentinel */ },

  };
  MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);

  
  static struct platform_driver s3c_rtc_driver = {

  	.probe		= s3c_rtc_probe,

  	.remove		= s3c_rtc_remove,

  	.driver		= {

  		.name	= "s3c-rtc",

  		.pm	= &s3c_rtc_pm_ops,

  		.of_match_table	= of_match_ptr(s3c_rtc_dt_match),

  	},
  };

  module_platform_driver(s3c_rtc_driver);

  
  MODULE_DESCRIPTION("Samsung S3C RTC Driver");
  MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:s3c2410-rtc");