drivers/rtc/rtc-s3c.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /* 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 <mach/hardware.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/irq.h>
 #include <plat/regs-rtc.h>

 enum s3c_cpu_type {
 	TYPE_S3C2410,
 	TYPE_S3C64XX,
 };

 /* I have yet to find an S3C implementation with more than one
  * of these rtc blocks in */

 static struct resource *s3c_rtc_mem;

 static struct clk *rtc_clk;
 static void __iomem *s3c_rtc_base;
 static int s3c_rtc_alarmno = NO_IRQ;
 static int s3c_rtc_tickno  = NO_IRQ;
 static bool wake_en;
 static enum s3c_cpu_type s3c_rtc_cpu_type;

 static DEFINE_SPINLOCK(s3c_rtc_pie_lock);

 /* IRQ Handlers */

 static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
 {
 	struct rtc_device *rdev = id;

 	rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);

 	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 		writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);

 	return IRQ_HANDLED;
 }

 static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
 {
 	struct rtc_device *rdev = id;

 	rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);

 	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 		writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);

 	return IRQ_HANDLED;
 }

 /* Update control registers */
 static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 {
 	unsigned int tmp;

 	pr_debug("%s: aie=%d\n", __func__, enabled);

 	tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;

 	if (enabled)
 		tmp |= S3C2410_RTCALM_ALMEN;

 	writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);

 	return 0;
 }

 static int s3c_rtc_setfreq(struct device *dev, int freq)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
 	unsigned int tmp = 0;

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

 	spin_lock_irq(&s3c_rtc_pie_lock);

 	if (s3c_rtc_cpu_type == TYPE_S3C2410) {
 		tmp = readb(s3c_rtc_base + S3C2410_TICNT);
 		tmp &= S3C2410_TICNT_ENABLE;
 	}

 	tmp |= (rtc_dev->max_user_freq / freq)-1;

 	writel(tmp, s3c_rtc_base + S3C2410_TICNT);
 	spin_unlock_irq(&s3c_rtc_pie_lock);

 	return 0;
 }

 /* Time read/write */

 static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 {
 	unsigned int have_retried = 0;
 	void __iomem *base = s3c_rtc_base;

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

 	/* the only way to work out wether 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;
 	}

 	pr_debug("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_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);

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

 	return rtc_valid_tm(rtc_tm);
 }

 static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
 {
 	void __iomem *base = s3c_rtc_base;
 	int year = tm->tm_year - 100;

 	pr_debug("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;
 	}

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

 	return 0;
 }

 static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rtc_time *alm_tm = &alrm->time;
 	void __iomem *base = s3c_rtc_base;
 	unsigned int alm_en;

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

 	alm_en = readb(base + S3C2410_RTCALM);

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

 	pr_debug("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 rtc_time *tm = &alrm->time;
 	void __iomem *base = s3c_rtc_base;
 	unsigned int alrm_en;

 	pr_debug("s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
 		 alrm->enabled,
 		 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 		 tm->tm_hour, tm->tm_min, tm->tm_sec);


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

 	if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
 		alrm_en |= S3C2410_RTCALM_SECEN;
 		writeb(bin2bcd(tm->tm_sec), base + S3C2410_ALMSEC);
 	}

 	if (tm->tm_min < 60 && tm->tm_min >= 0) {
 		alrm_en |= S3C2410_RTCALM_MINEN;
 		writeb(bin2bcd(tm->tm_min), base + S3C2410_ALMMIN);
 	}

 	if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
 		alrm_en |= S3C2410_RTCALM_HOUREN;
 		writeb(bin2bcd(tm->tm_hour), base + S3C2410_ALMHOUR);
 	}

 	pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);

 	writeb(alrm_en, base + S3C2410_RTCALM);

 	s3c_rtc_setaie(dev, alrm->enabled);

 	return 0;
 }

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

 	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
 		ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);
 		ticnt &= S3C64XX_RTCCON_TICEN;
 	} else {
 		ticnt = readb(s3c_rtc_base + S3C2410_TICNT);
 		ticnt &= S3C2410_TICNT_ENABLE;
 	}

 	seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt  ? "yes" : "no");
 	return 0;
 }

 static int s3c_rtc_open(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
 	int ret;

 	ret = request_irq(s3c_rtc_alarmno, s3c_rtc_alarmirq,
 			  IRQF_DISABLED,  "s3c2410-rtc alarm", rtc_dev);

 	if (ret) {
 		dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);
 		return ret;
 	}

 	ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,
 			  IRQF_DISABLED,  "s3c2410-rtc tick", rtc_dev);

 	if (ret) {
 		dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);
 		goto tick_err;
 	}

 	return ret;

  tick_err:
 	free_irq(s3c_rtc_alarmno, rtc_dev);
 	return ret;
 }

 static void s3c_rtc_release(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);

 	/* do not clear AIE here, it may be needed for wake */

 	free_irq(s3c_rtc_alarmno, rtc_dev);
 	free_irq(s3c_rtc_tickno, rtc_dev);
 }

 static const struct rtc_class_ops s3c_rtcops = {
 	.open		= s3c_rtc_open,
 	.release	= s3c_rtc_release,
 	.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 s3c_rtc_enable(struct platform_device *pdev, int en)
 {
 	void __iomem *base = s3c_rtc_base;
 	unsigned int tmp;

 	if (s3c_rtc_base == NULL)
 		return;

 	if (!en) {
 		tmp = readw(base + S3C2410_RTCCON);
 		if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 			tmp &= ~S3C64XX_RTCCON_TICEN;
 		tmp &= ~S3C2410_RTCCON_RTCEN;
 		writew(tmp, base + S3C2410_RTCCON);

 		if (s3c_rtc_cpu_type == TYPE_S3C2410) {
 			tmp = readb(base + S3C2410_TICNT);
 			tmp &= ~S3C2410_TICNT_ENABLE;
 			writeb(tmp, base + S3C2410_TICNT);
 		}
 	} else {
 		/* re-enable the device, and check it is ok */

 		if ((readw(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0) {
 			dev_info(&pdev->dev, "rtc disabled, re-enabling\n");

 			tmp = readw(base + S3C2410_RTCCON);
 			writew(tmp | S3C2410_RTCCON_RTCEN,
 				base + S3C2410_RTCCON);
 		}

 		if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)) {
 			dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");

 			tmp = readw(base + S3C2410_RTCCON);
 			writew(tmp & ~S3C2410_RTCCON_CNTSEL,
 				base + S3C2410_RTCCON);
 		}

 		if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)) {
 			dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");

 			tmp = readw(base + S3C2410_RTCCON);
 			writew(tmp & ~S3C2410_RTCCON_CLKRST,
 				base + S3C2410_RTCCON);
 		}
 	}
 }

 static int __devexit s3c_rtc_remove(struct platform_device *dev)
 {
 	struct rtc_device *rtc = platform_get_drvdata(dev);

 	platform_set_drvdata(dev, NULL);
 	rtc_device_unregister(rtc);

 	s3c_rtc_setaie(&dev->dev, 0);

 	clk_disable(rtc_clk);
 	clk_put(rtc_clk);
 	rtc_clk = NULL;

 	iounmap(s3c_rtc_base);
 	release_resource(s3c_rtc_mem);
 	kfree(s3c_rtc_mem);

 	return 0;
 }

 static int __devinit s3c_rtc_probe(struct platform_device *pdev)
 {
 	struct rtc_device *rtc;
 	struct rtc_time rtc_tm;
 	struct resource *res;
 	int ret;

 	pr_debug("%s: probe=%p\n", __func__, pdev);

 	/* find the IRQs */

 	s3c_rtc_tickno = platform_get_irq(pdev, 1);
 	if (s3c_rtc_tickno < 0) {
 		dev_err(&pdev->dev, "no irq for rtc tick\n");
 		return -ENOENT;
 	}

 	s3c_rtc_alarmno = platform_get_irq(pdev, 0);
 	if (s3c_rtc_alarmno < 0) {
 		dev_err(&pdev->dev, "no irq for alarm\n");
 		return -ENOENT;
 	}

 	pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
 		 s3c_rtc_tickno, s3c_rtc_alarmno);

 	/* get the memory region */

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res == NULL) {
 		dev_err(&pdev->dev, "failed to get memory region resource\n");
 		return -ENOENT;
 	}

 	s3c_rtc_mem = request_mem_region(res->start, resource_size(res),
 					 pdev->name);

 	if (s3c_rtc_mem == NULL) {
 		dev_err(&pdev->dev, "failed to reserve memory region\n");
 		ret = -ENOENT;
 		goto err_nores;
 	}

 	s3c_rtc_base = ioremap(res->start, resource_size(res));
 	if (s3c_rtc_base == NULL) {
 		dev_err(&pdev->dev, "failed ioremap()\n");
 		ret = -EINVAL;
 		goto err_nomap;
 	}

 	rtc_clk = clk_get(&pdev->dev, "rtc");
 	if (IS_ERR(rtc_clk)) {
 		dev_err(&pdev->dev, "failed to find rtc clock source\n");
 		ret = PTR_ERR(rtc_clk);
 		rtc_clk = NULL;
 		goto err_clk;
 	}

 	clk_enable(rtc_clk);

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

 	s3c_rtc_enable(pdev, 1);

 	pr_debug("s3c2410_rtc: RTCCON=%02x\n",
 		 readw(s3c_rtc_base + S3C2410_RTCCON));

 	device_init_wakeup(&pdev->dev, 1);

 	/* register RTC and exit */

 	rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,
 				  THIS_MODULE);

 	if (IS_ERR(rtc)) {
 		dev_err(&pdev->dev, "cannot attach rtc\n");
 		ret = PTR_ERR(rtc);
 		goto err_nortc;
 	}

 	s3c_rtc_cpu_type = platform_get_device_id(pdev)->driver_data;

 	/* Check RTC Time */

 	s3c_rtc_gettime(NULL, &rtc_tm);

 	if (rtc_valid_tm(&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(NULL, &rtc_tm);

 		dev_warn(&pdev->dev, "warning: invalid RTC value so initializing it\n");
 	}

 	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
 		rtc->max_user_freq = 32768;
 	else
 		rtc->max_user_freq = 128;

 	platform_set_drvdata(pdev, rtc);

 	s3c_rtc_setfreq(&pdev->dev, 1);

 	return 0;

  err_nortc:
 	s3c_rtc_enable(pdev, 0);
 	clk_disable(rtc_clk);
 	clk_put(rtc_clk);

  err_clk:
 	iounmap(s3c_rtc_base);

  err_nomap:
 	release_resource(s3c_rtc_mem);

  err_nores:
 	return ret;
 }

 #ifdef CONFIG_PM

 /* RTC Power management control */

 static int ticnt_save, ticnt_en_save;

 static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	/* save TICNT for anyone using periodic interrupts */
 	ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
 		ticnt_en_save = readw(s3c_rtc_base + S3C2410_RTCCON);
 		ticnt_en_save &= S3C64XX_RTCCON_TICEN;
 	}
 	s3c_rtc_enable(pdev, 0);

 	if (device_may_wakeup(&pdev->dev) && !wake_en) {
 		if (enable_irq_wake(s3c_rtc_alarmno) == 0)
 			wake_en = true;
 		else
 			dev_err(&pdev->dev, "enable_irq_wake failed\n");
 	}

 	return 0;
 }

 static int s3c_rtc_resume(struct platform_device *pdev)
 {
 	unsigned int tmp;

 	s3c_rtc_enable(pdev, 1);
 	writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
 	if (s3c_rtc_cpu_type == TYPE_S3C64XX && ticnt_en_save) {
 		tmp = readw(s3c_rtc_base + S3C2410_RTCCON);
 		writew(tmp | ticnt_en_save, s3c_rtc_base + S3C2410_RTCCON);
 	}

 	if (device_may_wakeup(&pdev->dev) && wake_en) {
 		disable_irq_wake(s3c_rtc_alarmno);
 		wake_en = false;
 	}

 	return 0;
 }
 #else
 #define s3c_rtc_suspend NULL
 #define s3c_rtc_resume  NULL
 #endif

 static struct platform_device_id s3c_rtc_driver_ids[] = {
 	{
 		.name		= "s3c2410-rtc",
 		.driver_data	= TYPE_S3C2410,
 	}, {
 		.name		= "s3c64xx-rtc",
 		.driver_data	= TYPE_S3C64XX,
 	},
 	{ }
 };

 MODULE_DEVICE_TABLE(platform, s3c_rtc_driver_ids);

 static struct platform_driver s3c_rtc_driver = {
 	.probe		= s3c_rtc_probe,
 	.remove		= __devexit_p(s3c_rtc_remove),
 	.suspend	= s3c_rtc_suspend,
 	.resume		= s3c_rtc_resume,
 	.id_table	= s3c_rtc_driver_ids,
 	.driver		= {
 		.name	= "s3c-rtc",
 		.owner	= THIS_MODULE,
 	},
 };

 static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";

 static int __init s3c_rtc_init(void)
 {
 	printk(banner);
 	return platform_driver_register(&s3c_rtc_driver);
 }

 static void __exit s3c_rtc_exit(void)
 {
 	platform_driver_unregister(&s3c_rtc_driver);
 }

 module_init(s3c_rtc_init);
 module_exit(s3c_rtc_exit);

 MODULE_DESCRIPTION("Samsung S3C RTC Driver");
 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:s3c2410-rtc");
	/* 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 <mach/hardware.h>
	#include <asm/uaccess.h>
	#include <asm/io.h>
	#include <asm/irq.h>
	#include <plat/regs-rtc.h>

	enum s3c_cpu_type {
	TYPE_S3C2410,
	TYPE_S3C64XX,
	};

	/* I have yet to find an S3C implementation with more than one
	* of these rtc blocks in */

	static struct resource *s3c_rtc_mem;

	static struct clk *rtc_clk;
	static void __iomem *s3c_rtc_base;
	static int s3c_rtc_alarmno = NO_IRQ;
	static int s3c_rtc_tickno = NO_IRQ;
	static bool wake_en;
	static enum s3c_cpu_type s3c_rtc_cpu_type;

	static DEFINE_SPINLOCK(s3c_rtc_pie_lock);

	/* IRQ Handlers */

	static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
	{
	struct rtc_device *rdev = id;

	rtc_update_irq(rdev, 1, RTC_AF \| RTC_IRQF);

	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
	writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);

	return IRQ_HANDLED;
	}

	static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
	{
	struct rtc_device *rdev = id;

	rtc_update_irq(rdev, 1, RTC_PF \| RTC_IRQF);

	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
	writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);

	return IRQ_HANDLED;
	}

	/* Update control registers */
	static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
	{
	unsigned int tmp;

	pr_debug("%s: aie=%d\n", __func__, enabled);

	tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;

	if (enabled)
	tmp \|= S3C2410_RTCALM_ALMEN;

	writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);

	return 0;
	}

	static int s3c_rtc_setfreq(struct device *dev, int freq)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
	unsigned int tmp = 0;

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

	spin_lock_irq(&s3c_rtc_pie_lock);

	if (s3c_rtc_cpu_type == TYPE_S3C2410) {
	tmp = readb(s3c_rtc_base + S3C2410_TICNT);
	tmp &= S3C2410_TICNT_ENABLE;
	}

	tmp \|= (rtc_dev->max_user_freq / freq)-1;

	writel(tmp, s3c_rtc_base + S3C2410_TICNT);
	spin_unlock_irq(&s3c_rtc_pie_lock);

	return 0;
	}

	/* Time read/write */

	static int s3c_rtc_gettime(struct device dev, struct rtc_time rtc_tm)
	{
	unsigned int have_retried = 0;
	void __iomem *base = s3c_rtc_base;

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

	/* the only way to work out wether 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;
	}

	pr_debug("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_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);

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

	return rtc_valid_tm(rtc_tm);
	}

	static int s3c_rtc_settime(struct device dev, struct rtc_time tm)
	{
	void __iomem *base = s3c_rtc_base;
	int year = tm->tm_year - 100;

	pr_debug("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;
	}

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

	return 0;
	}

	static int s3c_rtc_getalarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rtc_time *alm_tm = &alrm->time;
	void __iomem *base = s3c_rtc_base;
	unsigned int alm_en;

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

	alm_en = readb(base + S3C2410_RTCALM);

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

	pr_debug("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 rtc_time *tm = &alrm->time;
	void __iomem *base = s3c_rtc_base;
	unsigned int alrm_en;

	pr_debug("s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
	alrm->enabled,
	1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);


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

	if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
	alrm_en \|= S3C2410_RTCALM_SECEN;
	writeb(bin2bcd(tm->tm_sec), base + S3C2410_ALMSEC);
	}

	if (tm->tm_min < 60 && tm->tm_min >= 0) {
	alrm_en \|= S3C2410_RTCALM_MINEN;
	writeb(bin2bcd(tm->tm_min), base + S3C2410_ALMMIN);
	}

	if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
	alrm_en \|= S3C2410_RTCALM_HOUREN;
	writeb(bin2bcd(tm->tm_hour), base + S3C2410_ALMHOUR);
	}

	pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);

	writeb(alrm_en, base + S3C2410_RTCALM);

	s3c_rtc_setaie(dev, alrm->enabled);

	return 0;
	}

	static int s3c_rtc_proc(struct device dev, struct seq_file seq)
	{
	unsigned int ticnt;

	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
	ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);
	ticnt &= S3C64XX_RTCCON_TICEN;
	} else {
	ticnt = readb(s3c_rtc_base + S3C2410_TICNT);
	ticnt &= S3C2410_TICNT_ENABLE;
	}

	seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt ? "yes" : "no");
	return 0;
	}

	static int s3c_rtc_open(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
	int ret;

	ret = request_irq(s3c_rtc_alarmno, s3c_rtc_alarmirq,
	IRQF_DISABLED, "s3c2410-rtc alarm", rtc_dev);

	if (ret) {
	dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);
	return ret;
	}

	ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,
	IRQF_DISABLED, "s3c2410-rtc tick", rtc_dev);

	if (ret) {
	dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);
	goto tick_err;
	}

	return ret;

	tick_err:
	free_irq(s3c_rtc_alarmno, rtc_dev);
	return ret;
	}

	static void s3c_rtc_release(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_device *rtc_dev = platform_get_drvdata(pdev);

	/* do not clear AIE here, it may be needed for wake */

	free_irq(s3c_rtc_alarmno, rtc_dev);
	free_irq(s3c_rtc_tickno, rtc_dev);
	}

	static const struct rtc_class_ops s3c_rtcops = {
	.open = s3c_rtc_open,
	.release = s3c_rtc_release,
	.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 s3c_rtc_enable(struct platform_device *pdev, int en)
	{
	void __iomem *base = s3c_rtc_base;
	unsigned int tmp;

	if (s3c_rtc_base == NULL)
	return;

	if (!en) {
	tmp = readw(base + S3C2410_RTCCON);
	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
	tmp &= ~S3C64XX_RTCCON_TICEN;
	tmp &= ~S3C2410_RTCCON_RTCEN;
	writew(tmp, base + S3C2410_RTCCON);

	if (s3c_rtc_cpu_type == TYPE_S3C2410) {
	tmp = readb(base + S3C2410_TICNT);
	tmp &= ~S3C2410_TICNT_ENABLE;
	writeb(tmp, base + S3C2410_TICNT);
	}
	} else {
	/* re-enable the device, and check it is ok */

	if ((readw(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0) {
	dev_info(&pdev->dev, "rtc disabled, re-enabling\n");

	tmp = readw(base + S3C2410_RTCCON);
	writew(tmp \| S3C2410_RTCCON_RTCEN,
	base + S3C2410_RTCCON);
	}

	if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)) {
	dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");

	tmp = readw(base + S3C2410_RTCCON);
	writew(tmp & ~S3C2410_RTCCON_CNTSEL,
	base + S3C2410_RTCCON);
	}

	if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)) {
	dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");

	tmp = readw(base + S3C2410_RTCCON);
	writew(tmp & ~S3C2410_RTCCON_CLKRST,
	base + S3C2410_RTCCON);
	}
	}
	}

	static int __devexit s3c_rtc_remove(struct platform_device *dev)
	{
	struct rtc_device *rtc = platform_get_drvdata(dev);

	platform_set_drvdata(dev, NULL);
	rtc_device_unregister(rtc);

	s3c_rtc_setaie(&dev->dev, 0);

	clk_disable(rtc_clk);
	clk_put(rtc_clk);
	rtc_clk = NULL;

	iounmap(s3c_rtc_base);
	release_resource(s3c_rtc_mem);
	kfree(s3c_rtc_mem);

	return 0;
	}

	static int __devinit s3c_rtc_probe(struct platform_device *pdev)
	{
	struct rtc_device *rtc;
	struct rtc_time rtc_tm;
	struct resource *res;
	int ret;

	pr_debug("%s: probe=%p\n", __func__, pdev);

	/* find the IRQs */

	s3c_rtc_tickno = platform_get_irq(pdev, 1);
	if (s3c_rtc_tickno < 0) {
	dev_err(&pdev->dev, "no irq for rtc tick\n");
	return -ENOENT;
	}

	s3c_rtc_alarmno = platform_get_irq(pdev, 0);
	if (s3c_rtc_alarmno < 0) {
	dev_err(&pdev->dev, "no irq for alarm\n");
	return -ENOENT;
	}

	pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",
	s3c_rtc_tickno, s3c_rtc_alarmno);

	/* get the memory region */

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
	dev_err(&pdev->dev, "failed to get memory region resource\n");
	return -ENOENT;
	}

	s3c_rtc_mem = request_mem_region(res->start, resource_size(res),
	pdev->name);

	if (s3c_rtc_mem == NULL) {
	dev_err(&pdev->dev, "failed to reserve memory region\n");
	ret = -ENOENT;
	goto err_nores;
	}

	s3c_rtc_base = ioremap(res->start, resource_size(res));
	if (s3c_rtc_base == NULL) {
	dev_err(&pdev->dev, "failed ioremap()\n");
	ret = -EINVAL;
	goto err_nomap;
	}

	rtc_clk = clk_get(&pdev->dev, "rtc");
	if (IS_ERR(rtc_clk)) {
	dev_err(&pdev->dev, "failed to find rtc clock source\n");
	ret = PTR_ERR(rtc_clk);
	rtc_clk = NULL;
	goto err_clk;
	}

	clk_enable(rtc_clk);

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

	s3c_rtc_enable(pdev, 1);

	pr_debug("s3c2410_rtc: RTCCON=%02x\n",
	readw(s3c_rtc_base + S3C2410_RTCCON));

	device_init_wakeup(&pdev->dev, 1);

	/* register RTC and exit */

	rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,
	THIS_MODULE);

	if (IS_ERR(rtc)) {
	dev_err(&pdev->dev, "cannot attach rtc\n");
	ret = PTR_ERR(rtc);
	goto err_nortc;
	}

	s3c_rtc_cpu_type = platform_get_device_id(pdev)->driver_data;

	/* Check RTC Time */

	s3c_rtc_gettime(NULL, &rtc_tm);

	if (rtc_valid_tm(&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(NULL, &rtc_tm);

	dev_warn(&pdev->dev, "warning: invalid RTC value so initializing it\n");
	}

	if (s3c_rtc_cpu_type == TYPE_S3C64XX)
	rtc->max_user_freq = 32768;
	else
	rtc->max_user_freq = 128;

	platform_set_drvdata(pdev, rtc);

	s3c_rtc_setfreq(&pdev->dev, 1);

	return 0;

	err_nortc:
	s3c_rtc_enable(pdev, 0);
	clk_disable(rtc_clk);
	clk_put(rtc_clk);

	err_clk:
	iounmap(s3c_rtc_base);

	err_nomap:
	release_resource(s3c_rtc_mem);

	err_nores:
	return ret;
	}

	#ifdef CONFIG_PM

	/* RTC Power management control */

	static int ticnt_save, ticnt_en_save;

	static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
	{
	/* save TICNT for anyone using periodic interrupts */
	ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);
	if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
	ticnt_en_save = readw(s3c_rtc_base + S3C2410_RTCCON);
	ticnt_en_save &= S3C64XX_RTCCON_TICEN;
	}
	s3c_rtc_enable(pdev, 0);

	if (device_may_wakeup(&pdev->dev) && !wake_en) {
	if (enable_irq_wake(s3c_rtc_alarmno) == 0)
	wake_en = true;
	else
	dev_err(&pdev->dev, "enable_irq_wake failed\n");
	}

	return 0;
	}

	static int s3c_rtc_resume(struct platform_device *pdev)
	{
	unsigned int tmp;

	s3c_rtc_enable(pdev, 1);
	writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
	if (s3c_rtc_cpu_type == TYPE_S3C64XX && ticnt_en_save) {
	tmp = readw(s3c_rtc_base + S3C2410_RTCCON);
	writew(tmp \| ticnt_en_save, s3c_rtc_base + S3C2410_RTCCON);
	}

	if (device_may_wakeup(&pdev->dev) && wake_en) {
	disable_irq_wake(s3c_rtc_alarmno);
	wake_en = false;
	}

	return 0;
	}
	#else
	#define s3c_rtc_suspend NULL
	#define s3c_rtc_resume NULL
	#endif

	static struct platform_device_id s3c_rtc_driver_ids[] = {
	{
	.name = "s3c2410-rtc",
	.driver_data = TYPE_S3C2410,
	}, {
	.name = "s3c64xx-rtc",
	.driver_data = TYPE_S3C64XX,
	},
	{ }
	};

	MODULE_DEVICE_TABLE(platform, s3c_rtc_driver_ids);

	static struct platform_driver s3c_rtc_driver = {
	.probe = s3c_rtc_probe,
	.remove = __devexit_p(s3c_rtc_remove),
	.suspend = s3c_rtc_suspend,
	.resume = s3c_rtc_resume,
	.id_table = s3c_rtc_driver_ids,
	.driver = {
	.name = "s3c-rtc",
	.owner = THIS_MODULE,
	},
	};

	static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";

	static int __init s3c_rtc_init(void)
	{
	printk(banner);
	return platform_driver_register(&s3c_rtc_driver);
	}

	static void __exit s3c_rtc_exit(void)
	{
	platform_driver_unregister(&s3c_rtc_driver);
	}

	module_init(s3c_rtc_init);
	module_exit(s3c_rtc_exit);

	MODULE_DESCRIPTION("Samsung S3C RTC Driver");
	MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:s3c2410-rtc");