Initial import

1 files changed, 822 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
new file mode 100644
index 000000000..76cbad7a9
--- /dev/null
+++ b/drivers/rtc/rtc-s3c.c
@@ -0,0 +1,822 @@
+/* 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/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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/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;
+
+	struct s3c_rtc_data *data;
+
+	int irq_alarm;
+	int irq_tick;
+
+	spinlock_t pie_lock;
+	spinlock_t alarm_clk_lock;
+
+	int ticnt_save, 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 void s3c_rtc_enable_clk(struct s3c_rtc *info)
+{
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
+	clk_enable(info->rtc_clk);
+	if (info->data->needs_src_clk)
+		clk_enable(info->rtc_src_clk);
+	spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
+}
+
+static void s3c_rtc_disable_clk(struct s3c_rtc *info)
+{
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
+	if (info->data->needs_src_clk)
+		clk_disable(info->rtc_src_clk);
+	clk_disable(info->rtc_clk);
+	spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
+}
+
+/* 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 int tmp;
+
+	dev_dbg(info->dev, "%s: aie=%d\n", __func__, enabled);
+
+	s3c_rtc_enable_clk(info);
+
+	tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
+
+	if (enabled)
+		tmp |= S3C2410_RTCALM_ALMEN;
+
+	writeb(tmp, info->base + S3C2410_RTCALM);
+
+	s3c_rtc_disable_clk(info);
+
+	return 0;
+}
+
+/* Set RTC frequency */
+static int s3c_rtc_setfreq(struct s3c_rtc *info, int freq)
+{
+	if (!is_power_of_2(freq))
+		return -EINVAL;
+
+	spin_lock_irq(&info->pie_lock);
+
+	if (info->data->set_freq)
+		info->data->set_freq(info, freq);
+
+	spin_unlock_irq(&info->pie_lock);
+
+	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;
+
+	s3c_rtc_enable_clk(info);
+
+ 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;
+
+	dev_dbg(dev, "read time %04d.%02d.%02d %02d:%02d:%02d\n",
+		 1900 + rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
+		 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);
+
+	rtc_tm->tm_mon -= 1;
+
+	return rtc_valid_tm(rtc_tm);
+}
+
+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;
+
+	dev_dbg(dev, "set time %04d.%02d.%02d %02d:%02d:%02d\n",
+		 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
+		 tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	/* we get around y2k by simply not supporting it */
+
+	if (year < 0 || year >= 100) {
+		dev_err(dev, "rtc only supports 100 years\n");
+		return -EINVAL;
+	}
+
+	s3c_rtc_enable_clk(info);
+
+	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;
+
+	s3c_rtc_enable_clk(info);
+
+	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, %04d.%02d.%02d %02d:%02d:%02d\n",
+		 alm_en,
+		 1900 + alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
+		 alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);
+
+	/* decode the alarm enable field */
+	if (alm_en & S3C2410_RTCALM_SECEN)
+		alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
+	else
+		alm_tm->tm_sec = -1;
+
+	if (alm_en & S3C2410_RTCALM_MINEN)
+		alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
+	else
+		alm_tm->tm_min = -1;
+
+	if (alm_en & S3C2410_RTCALM_HOUREN)
+		alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
+	else
+		alm_tm->tm_hour = -1;
+
+	if (alm_en & S3C2410_RTCALM_DAYEN)
+		alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
+	else
+		alm_tm->tm_mday = -1;
+
+	if (alm_en & S3C2410_RTCALM_MONEN) {
+		alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
+		alm_tm->tm_mon -= 1;
+	} else {
+		alm_tm->tm_mon = -1;
+	}
+
+	if (alm_en & S3C2410_RTCALM_YEAREN)
+		alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
+	else
+		alm_tm->tm_year = -1;
+
+	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;
+
+	dev_dbg(dev, "s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
+		 alrm->enabled,
+		 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
+		 tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	s3c_rtc_enable_clk(info);
+
+	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);
+	}
+
+	dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);
+
+	writeb(alrm_en, info->base + S3C2410_RTCALM);
+
+	s3c_rtc_disable_clk(info);
+
+	s3c_rtc_setaie(dev, alrm->enabled);
+
+	return 0;
+}
+
+static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	struct s3c_rtc *info = dev_get_drvdata(dev);
+
+	s3c_rtc_enable_clk(info);
+
+	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\n");
+
+		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\n");
+
+		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\n");
+
+		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);
+
+	clk_unprepare(info->rtc_clk);
+	info->rtc_clk = NULL;
+
+	return 0;
+}
+
+static const struct of_device_id s3c_rtc_dt_match[];
+
+static struct s3c_rtc_data *s3c_rtc_get_data(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+
+	match = of_match_node(s3c_rtc_dt_match, pdev->dev.of_node);
+	return (struct s3c_rtc_data *)match->data;
+}
+
+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\n");
+		return info->irq_tick;
+	}
+
+	info->dev = &pdev->dev;
+	info->data = s3c_rtc_get_data(pdev);
+	if (!info->data) {
+		dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
+		return -EINVAL;
+	}
+	spin_lock_init(&info->pie_lock);
+	spin_lock_init(&info->alarm_clk_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\n");
+		return info->irq_alarm;
+	}
+
+	dev_dbg(&pdev->dev, "s3c2410_rtc: tick irq %d, alarm irq %d\n",
+		 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)) {
+		dev_err(&pdev->dev, "failed to find rtc clock\n");
+		return PTR_ERR(info->rtc_clk);
+	}
+	clk_prepare_enable(info->rtc_clk);
+
+	if (info->data->needs_src_clk) {
+		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
+		if (IS_ERR(info->rtc_src_clk)) {
+			dev_err(&pdev->dev,
+				"failed to find rtc source clock\n");
+			return PTR_ERR(info->rtc_src_clk);
+		}
+		clk_prepare_enable(info->rtc_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\n",
+		 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\n");
+	}
+
+	/* 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\n");
+		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\n", 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\n", 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);
+	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);
+
+	s3c_rtc_enable_clk(info);
+
+	/* 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\n");
+	}
+
+	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\n", 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\n", 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 struct s3c_rtc_data const exynos3250_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 = (void *)&s3c2410_rtc_data,
+	}, {
+		.compatible = "samsung,s3c2416-rtc",
+		.data = (void *)&s3c2416_rtc_data,
+	}, {
+		.compatible = "samsung,s3c2443-rtc",
+		.data = (void *)&s3c2443_rtc_data,
+	}, {
+		.compatible = "samsung,s3c6410-rtc",
+		.data = (void *)&s3c6410_rtc_data,
+	}, {
+		.compatible = "samsung,exynos3250-rtc",
+		.data = (void *)&exynos3250_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");