drivers/rtc/rtc-mxc.c - kernel/skids - Git at Google

 /*
  * Copyright 2004-2008 Freescale Semiconductor, Inc. All Rights Reserved.
  *
  * The code contained herein is licensed under the GNU General Public
  * License. You may obtain a copy of the GNU General Public License
  * Version 2 or later at the following locations:
  *
  * http://www.opensource.org/licenses/gpl-license.html
  * http://www.gnu.org/copyleft/gpl.html
  */

 #include <linux/io.h>
 #include <linux/rtc.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>

 #include <mach/hardware.h>

 #define RTC_INPUT_CLK_32768HZ	(0x00 << 5)
 #define RTC_INPUT_CLK_32000HZ	(0x01 << 5)
 #define RTC_INPUT_CLK_38400HZ	(0x02 << 5)

 #define RTC_SW_BIT      (1 << 0)
 #define RTC_ALM_BIT     (1 << 2)
 #define RTC_1HZ_BIT     (1 << 4)
 #define RTC_2HZ_BIT     (1 << 7)
 #define RTC_SAM0_BIT    (1 << 8)
 #define RTC_SAM1_BIT    (1 << 9)
 #define RTC_SAM2_BIT    (1 << 10)
 #define RTC_SAM3_BIT    (1 << 11)
 #define RTC_SAM4_BIT    (1 << 12)
 #define RTC_SAM5_BIT    (1 << 13)
 #define RTC_SAM6_BIT    (1 << 14)
 #define RTC_SAM7_BIT    (1 << 15)
 #define PIT_ALL_ON      (RTC_2HZ_BIT | RTC_SAM0_BIT | RTC_SAM1_BIT | \
 			 RTC_SAM2_BIT | RTC_SAM3_BIT | RTC_SAM4_BIT | \
 			 RTC_SAM5_BIT | RTC_SAM6_BIT | RTC_SAM7_BIT)

 #define RTC_ENABLE_BIT  (1 << 7)

 #define MAX_PIE_NUM     9
 #define MAX_PIE_FREQ    512
 static const u32 PIE_BIT_DEF[MAX_PIE_NUM][2] = {
 	{ 2,		RTC_2HZ_BIT },
 	{ 4,		RTC_SAM0_BIT },
 	{ 8,		RTC_SAM1_BIT },
 	{ 16,		RTC_SAM2_BIT },
 	{ 32,		RTC_SAM3_BIT },
 	{ 64,		RTC_SAM4_BIT },
 	{ 128,		RTC_SAM5_BIT },
 	{ 256,		RTC_SAM6_BIT },
 	{ MAX_PIE_FREQ,	RTC_SAM7_BIT },
 };

 /* Those are the bits from a classic RTC we want to mimic */
 #define RTC_IRQF	0x80	/* any of the following 3 is active */
 #define RTC_PF		0x40	/* Periodic interrupt */
 #define RTC_AF		0x20	/* Alarm interrupt */
 #define RTC_UF		0x10	/* Update interrupt for 1Hz RTC */

 #define MXC_RTC_TIME	0
 #define MXC_RTC_ALARM	1

 #define RTC_HOURMIN	0x00	/*  32bit rtc hour/min counter reg */
 #define RTC_SECOND	0x04	/*  32bit rtc seconds counter reg */
 #define RTC_ALRM_HM	0x08	/*  32bit rtc alarm hour/min reg */
 #define RTC_ALRM_SEC	0x0C	/*  32bit rtc alarm seconds reg */
 #define RTC_RTCCTL	0x10	/*  32bit rtc control reg */
 #define RTC_RTCISR	0x14	/*  32bit rtc interrupt status reg */
 #define RTC_RTCIENR	0x18	/*  32bit rtc interrupt enable reg */
 #define RTC_STPWCH	0x1C	/*  32bit rtc stopwatch min reg */
 #define RTC_DAYR	0x20	/*  32bit rtc days counter reg */
 #define RTC_DAYALARM	0x24	/*  32bit rtc day alarm reg */
 #define RTC_TEST1	0x28	/*  32bit rtc test reg 1 */
 #define RTC_TEST2	0x2C	/*  32bit rtc test reg 2 */
 #define RTC_TEST3	0x30	/*  32bit rtc test reg 3 */

 struct rtc_plat_data {
 	struct rtc_device *rtc;
 	void __iomem *ioaddr;
 	int irq;
 	struct clk *clk;
 	unsigned int irqen;
 	int alrm_sec;
 	int alrm_min;
 	int alrm_hour;
 	int alrm_mday;
 	struct timespec mxc_rtc_delta;
 	struct rtc_time g_rtc_alarm;
 };

 /*
  * This function is used to obtain the RTC time or the alarm value in
  * second.
  */
 static u32 get_alarm_or_time(struct device *dev, int time_alarm)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;
 	u32 day = 0, hr = 0, min = 0, sec = 0, hr_min = 0;

 	switch (time_alarm) {
 	case MXC_RTC_TIME:
 		day = readw(ioaddr + RTC_DAYR);
 		hr_min = readw(ioaddr + RTC_HOURMIN);
 		sec = readw(ioaddr + RTC_SECOND);
 		break;
 	case MXC_RTC_ALARM:
 		day = readw(ioaddr + RTC_DAYALARM);
 		hr_min = readw(ioaddr + RTC_ALRM_HM) & 0xffff;
 		sec = readw(ioaddr + RTC_ALRM_SEC);
 		break;
 	}

 	hr = hr_min >> 8;
 	min = hr_min & 0xff;

 	return (((day * 24 + hr) * 60) + min) * 60 + sec;
 }

 /*
  * This function sets the RTC alarm value or the time value.
  */
 static void set_alarm_or_time(struct device *dev, int time_alarm, u32 time)
 {
 	u32 day, hr, min, sec, temp;
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;

 	day = time / 86400;
 	time -= day * 86400;

 	/* time is within a day now */
 	hr = time / 3600;
 	time -= hr * 3600;

 	/* time is within an hour now */
 	min = time / 60;
 	sec = time - min * 60;

 	temp = (hr << 8) + min;

 	switch (time_alarm) {
 	case MXC_RTC_TIME:
 		writew(day, ioaddr + RTC_DAYR);
 		writew(sec, ioaddr + RTC_SECOND);
 		writew(temp, ioaddr + RTC_HOURMIN);
 		break;
 	case MXC_RTC_ALARM:
 		writew(day, ioaddr + RTC_DAYALARM);
 		writew(sec, ioaddr + RTC_ALRM_SEC);
 		writew(temp, ioaddr + RTC_ALRM_HM);
 		break;
 	}
 }

 /*
  * This function updates the RTC alarm registers and then clears all the
  * interrupt status bits.
  */
 static int rtc_update_alarm(struct device *dev, struct rtc_time *alrm)
 {
 	struct rtc_time alarm_tm, now_tm;
 	unsigned long now, time;
 	int ret;
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;

 	now = get_alarm_or_time(dev, MXC_RTC_TIME);
 	rtc_time_to_tm(now, &now_tm);
 	alarm_tm.tm_year = now_tm.tm_year;
 	alarm_tm.tm_mon = now_tm.tm_mon;
 	alarm_tm.tm_mday = now_tm.tm_mday;
 	alarm_tm.tm_hour = alrm->tm_hour;
 	alarm_tm.tm_min = alrm->tm_min;
 	alarm_tm.tm_sec = alrm->tm_sec;
 	rtc_tm_to_time(&now_tm, &now);
 	rtc_tm_to_time(&alarm_tm, &time);

 	if (time < now) {
 		time += 60 * 60 * 24;
 		rtc_time_to_tm(time, &alarm_tm);
 	}

 	ret = rtc_tm_to_time(&alarm_tm, &time);

 	/* clear all the interrupt status bits */
 	writew(readw(ioaddr + RTC_RTCISR), ioaddr + RTC_RTCISR);
 	set_alarm_or_time(dev, MXC_RTC_ALARM, time);

 	return ret;
 }

 /* This function is the RTC interrupt service routine. */
 static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
 {
 	struct platform_device *pdev = dev_id;
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;
 	u32 status;
 	u32 events = 0;

 	spin_lock_irq(&pdata->rtc->irq_lock);
 	status = readw(ioaddr + RTC_RTCISR) & readw(ioaddr + RTC_RTCIENR);
 	/* clear interrupt sources */
 	writew(status, ioaddr + RTC_RTCISR);

 	/* clear alarm interrupt if it has occurred */
 	if (status & RTC_ALM_BIT)
 		status &= ~RTC_ALM_BIT;

 	/* update irq data & counter */
 	if (status & RTC_ALM_BIT)
 		events |= (RTC_AF | RTC_IRQF);

 	if (status & RTC_1HZ_BIT)
 		events |= (RTC_UF | RTC_IRQF);

 	if (status & PIT_ALL_ON)
 		events |= (RTC_PF | RTC_IRQF);

 	if ((status & RTC_ALM_BIT) && rtc_valid_tm(&pdata->g_rtc_alarm))
 		rtc_update_alarm(&pdev->dev, &pdata->g_rtc_alarm);

 	rtc_update_irq(pdata->rtc, 1, events);
 	spin_unlock_irq(&pdata->rtc->irq_lock);

 	return IRQ_HANDLED;
 }

 /*
  * Clear all interrupts and release the IRQ
  */
 static void mxc_rtc_release(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;

 	spin_lock_irq(&pdata->rtc->irq_lock);

 	/* Disable all rtc interrupts */
 	writew(0, ioaddr + RTC_RTCIENR);

 	/* Clear all interrupt status */
 	writew(0xffffffff, ioaddr + RTC_RTCISR);

 	spin_unlock_irq(&pdata->rtc->irq_lock);
 }

 static void mxc_rtc_irq_enable(struct device *dev, unsigned int bit,
 				unsigned int enabled)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;
 	u32 reg;

 	spin_lock_irq(&pdata->rtc->irq_lock);
 	reg = readw(ioaddr + RTC_RTCIENR);

 	if (enabled)
 		reg |= bit;
 	else
 		reg &= ~bit;

 	writew(reg, ioaddr + RTC_RTCIENR);
 	spin_unlock_irq(&pdata->rtc->irq_lock);
 }

 static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, enabled);
 	return 0;
 }

 static int mxc_rtc_update_irq_enable(struct device *dev, unsigned int enabled)
 {
 	mxc_rtc_irq_enable(dev, RTC_1HZ_BIT, enabled);
 	return 0;
 }

 /*
  * This function reads the current RTC time into tm in Gregorian date.
  */
 static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	u32 val;

 	/* Avoid roll-over from reading the different registers */
 	do {
 		val = get_alarm_or_time(dev, MXC_RTC_TIME);
 	} while (val != get_alarm_or_time(dev, MXC_RTC_TIME));

 	rtc_time_to_tm(val, tm);

 	return 0;
 }

 /*
  * This function sets the internal RTC time based on tm in Gregorian date.
  */
 static int mxc_rtc_set_mmss(struct device *dev, unsigned long time)
 {
 	/* Avoid roll-over from reading the different registers */
 	do {
 		set_alarm_or_time(dev, MXC_RTC_TIME, time);
 	} while (time != get_alarm_or_time(dev, MXC_RTC_TIME));

 	return 0;
 }

 /*
  * This function reads the current alarm value into the passed in 'alrm'
  * argument. It updates the alrm's pending field value based on the whether
  * an alarm interrupt occurs or not.
  */
 static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	void __iomem *ioaddr = pdata->ioaddr;

 	rtc_time_to_tm(get_alarm_or_time(dev, MXC_RTC_ALARM), &alrm->time);
 	alrm->pending = ((readw(ioaddr + RTC_RTCISR) & RTC_ALM_BIT)) ? 1 : 0;

 	return 0;
 }

 /*
  * This function sets the RTC alarm based on passed in alrm.
  */
 static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 	int ret;

 	if (rtc_valid_tm(&alrm->time)) {
 		if (alrm->time.tm_sec > 59 ||
 		    alrm->time.tm_hour > 23 ||
 		    alrm->time.tm_min > 59)
 			return -EINVAL;

 		ret = rtc_update_alarm(dev, &alrm->time);
 	} else {
 		ret = rtc_valid_tm(&alrm->time);
 		if (ret)
 			return ret;

 		ret = rtc_update_alarm(dev, &alrm->time);
 	}

 	if (ret)
 		return ret;

 	memcpy(&pdata->g_rtc_alarm, &alrm->time, sizeof(struct rtc_time));
 	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, alrm->enabled);

 	return 0;
 }

 /* RTC layer */
 static struct rtc_class_ops mxc_rtc_ops = {
 	.release		= mxc_rtc_release,
 	.read_time		= mxc_rtc_read_time,
 	.set_mmss		= mxc_rtc_set_mmss,
 	.read_alarm		= mxc_rtc_read_alarm,
 	.set_alarm		= mxc_rtc_set_alarm,
 	.alarm_irq_enable	= mxc_rtc_alarm_irq_enable,
 	.update_irq_enable	= mxc_rtc_update_irq_enable,
 };

 static int __init mxc_rtc_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct rtc_device *rtc;
 	struct rtc_plat_data *pdata = NULL;
 	u32 reg;
 	unsigned long rate;
 	int ret;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;

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

 	if (!devm_request_mem_region(&pdev->dev, res->start,
 				     resource_size(res), pdev->name))
 		return -EBUSY;

 	pdata->ioaddr = devm_ioremap(&pdev->dev, res->start,
 				     resource_size(res));

 	pdata->clk = clk_get(&pdev->dev, "rtc");
 	if (IS_ERR(pdata->clk)) {
 		dev_err(&pdev->dev, "unable to get clock!\n");
 		ret = PTR_ERR(pdata->clk);
 		goto exit_free_pdata;
 	}

 	clk_enable(pdata->clk);
 	rate = clk_get_rate(pdata->clk);

 	if (rate == 32768)
 		reg = RTC_INPUT_CLK_32768HZ;
 	else if (rate == 32000)
 		reg = RTC_INPUT_CLK_32000HZ;
 	else if (rate == 38400)
 		reg = RTC_INPUT_CLK_38400HZ;
 	else {
 		dev_err(&pdev->dev, "rtc clock is not valid (%lu)\n", rate);
 		ret = -EINVAL;
 		goto exit_put_clk;
 	}

 	reg |= RTC_ENABLE_BIT;
 	writew(reg, (pdata->ioaddr + RTC_RTCCTL));
 	if (((readw(pdata->ioaddr + RTC_RTCCTL)) & RTC_ENABLE_BIT) == 0) {
 		dev_err(&pdev->dev, "hardware module can't be enabled!\n");
 		ret = -EIO;
 		goto exit_put_clk;
 	}

 	rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
 				  THIS_MODULE);
 	if (IS_ERR(rtc)) {
 		ret = PTR_ERR(rtc);
 		goto exit_put_clk;
 	}

 	pdata->rtc = rtc;
 	platform_set_drvdata(pdev, pdata);

 	/* Configure and enable the RTC */
 	pdata->irq = platform_get_irq(pdev, 0);

 	if (pdata->irq >= 0 &&
 	    devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt,
 			     IRQF_SHARED, pdev->name, pdev) < 0) {
 		dev_warn(&pdev->dev, "interrupt not available.\n");
 		pdata->irq = -1;
 	}

 	return 0;

 exit_put_clk:
 	clk_disable(pdata->clk);
 	clk_put(pdata->clk);

 exit_free_pdata:

 	return ret;
 }

 static int __exit mxc_rtc_remove(struct platform_device *pdev)
 {
 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

 	rtc_device_unregister(pdata->rtc);

 	clk_disable(pdata->clk);
 	clk_put(pdata->clk);
 	platform_set_drvdata(pdev, NULL);

 	return 0;
 }

 static struct platform_driver mxc_rtc_driver = {
 	.driver = {
 		   .name	= "mxc_rtc",
 		   .owner	= THIS_MODULE,
 	},
 	.remove		= __exit_p(mxc_rtc_remove),
 };

 static int __init mxc_rtc_init(void)
 {
 	return platform_driver_probe(&mxc_rtc_driver, mxc_rtc_probe);
 }

 static void __exit mxc_rtc_exit(void)
 {
 	platform_driver_unregister(&mxc_rtc_driver);
 }

 module_init(mxc_rtc_init);
 module_exit(mxc_rtc_exit);

 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 MODULE_DESCRIPTION("RTC driver for Freescale MXC");
 MODULE_LICENSE("GPL");
	/*
	* Copyright 2004-2008 Freescale Semiconductor, Inc. All Rights Reserved.
	*
	* The code contained herein is licensed under the GNU General Public
	* License. You may obtain a copy of the GNU General Public License
	* Version 2 or later at the following locations:
	*
	* http://www.opensource.org/licenses/gpl-license.html
	* http://www.gnu.org/copyleft/gpl.html
	*/

	#include <linux/io.h>
	#include <linux/rtc.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/clk.h>

	#include <mach/hardware.h>

	#define RTC_INPUT_CLK_32768HZ (0x00 << 5)
	#define RTC_INPUT_CLK_32000HZ (0x01 << 5)
	#define RTC_INPUT_CLK_38400HZ (0x02 << 5)

	#define RTC_SW_BIT (1 << 0)
	#define RTC_ALM_BIT (1 << 2)
	#define RTC_1HZ_BIT (1 << 4)
	#define RTC_2HZ_BIT (1 << 7)
	#define RTC_SAM0_BIT (1 << 8)
	#define RTC_SAM1_BIT (1 << 9)
	#define RTC_SAM2_BIT (1 << 10)
	#define RTC_SAM3_BIT (1 << 11)
	#define RTC_SAM4_BIT (1 << 12)
	#define RTC_SAM5_BIT (1 << 13)
	#define RTC_SAM6_BIT (1 << 14)
	#define RTC_SAM7_BIT (1 << 15)
	#define PIT_ALL_ON (RTC_2HZ_BIT \| RTC_SAM0_BIT \| RTC_SAM1_BIT \| \
	RTC_SAM2_BIT \| RTC_SAM3_BIT \| RTC_SAM4_BIT \| \
	RTC_SAM5_BIT \| RTC_SAM6_BIT \| RTC_SAM7_BIT)

	#define RTC_ENABLE_BIT (1 << 7)

	#define MAX_PIE_NUM 9
	#define MAX_PIE_FREQ 512
	static const u32 PIE_BIT_DEF[MAX_PIE_NUM][2] = {
	{ 2, RTC_2HZ_BIT },
	{ 4, RTC_SAM0_BIT },
	{ 8, RTC_SAM1_BIT },
	{ 16, RTC_SAM2_BIT },
	{ 32, RTC_SAM3_BIT },
	{ 64, RTC_SAM4_BIT },
	{ 128, RTC_SAM5_BIT },
	{ 256, RTC_SAM6_BIT },
	{ MAX_PIE_FREQ, RTC_SAM7_BIT },
	};

	/* Those are the bits from a classic RTC we want to mimic */
	#define RTC_IRQF 0x80 /* any of the following 3 is active */
	#define RTC_PF 0x40 /* Periodic interrupt */
	#define RTC_AF 0x20 /* Alarm interrupt */
	#define RTC_UF 0x10 /* Update interrupt for 1Hz RTC */

	#define MXC_RTC_TIME 0
	#define MXC_RTC_ALARM 1

	#define RTC_HOURMIN 0x00 /* 32bit rtc hour/min counter reg */
	#define RTC_SECOND 0x04 /* 32bit rtc seconds counter reg */
	#define RTC_ALRM_HM 0x08 /* 32bit rtc alarm hour/min reg */
	#define RTC_ALRM_SEC 0x0C /* 32bit rtc alarm seconds reg */
	#define RTC_RTCCTL 0x10 /* 32bit rtc control reg */
	#define RTC_RTCISR 0x14 /* 32bit rtc interrupt status reg */
	#define RTC_RTCIENR 0x18 /* 32bit rtc interrupt enable reg */
	#define RTC_STPWCH 0x1C /* 32bit rtc stopwatch min reg */
	#define RTC_DAYR 0x20 /* 32bit rtc days counter reg */
	#define RTC_DAYALARM 0x24 /* 32bit rtc day alarm reg */
	#define RTC_TEST1 0x28 /* 32bit rtc test reg 1 */
	#define RTC_TEST2 0x2C /* 32bit rtc test reg 2 */
	#define RTC_TEST3 0x30 /* 32bit rtc test reg 3 */

	struct rtc_plat_data {
	struct rtc_device *rtc;
	void __iomem *ioaddr;
	int irq;
	struct clk *clk;
	unsigned int irqen;
	int alrm_sec;
	int alrm_min;
	int alrm_hour;
	int alrm_mday;
	struct timespec mxc_rtc_delta;
	struct rtc_time g_rtc_alarm;
	};

	/*
	* This function is used to obtain the RTC time or the alarm value in
	* second.
	*/
	static u32 get_alarm_or_time(struct device *dev, int time_alarm)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 day = 0, hr = 0, min = 0, sec = 0, hr_min = 0;

	switch (time_alarm) {
	case MXC_RTC_TIME:
	day = readw(ioaddr + RTC_DAYR);
	hr_min = readw(ioaddr + RTC_HOURMIN);
	sec = readw(ioaddr + RTC_SECOND);
	break;
	case MXC_RTC_ALARM:
	day = readw(ioaddr + RTC_DAYALARM);
	hr_min = readw(ioaddr + RTC_ALRM_HM) & 0xffff;
	sec = readw(ioaddr + RTC_ALRM_SEC);
	break;
	}

	hr = hr_min >> 8;
	min = hr_min & 0xff;

	return (((day * 24 + hr) * 60) + min) * 60 + sec;
	}

	/*
	* This function sets the RTC alarm value or the time value.
	*/
	static void set_alarm_or_time(struct device *dev, int time_alarm, u32 time)
	{
	u32 day, hr, min, sec, temp;
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	day = time / 86400;
	time -= day * 86400;

	/* time is within a day now */
	hr = time / 3600;
	time -= hr * 3600;

	/* time is within an hour now */
	min = time / 60;
	sec = time - min * 60;

	temp = (hr << 8) + min;

	switch (time_alarm) {
	case MXC_RTC_TIME:
	writew(day, ioaddr + RTC_DAYR);
	writew(sec, ioaddr + RTC_SECOND);
	writew(temp, ioaddr + RTC_HOURMIN);
	break;
	case MXC_RTC_ALARM:
	writew(day, ioaddr + RTC_DAYALARM);
	writew(sec, ioaddr + RTC_ALRM_SEC);
	writew(temp, ioaddr + RTC_ALRM_HM);
	break;
	}
	}

	/*
	* This function updates the RTC alarm registers and then clears all the
	* interrupt status bits.
	*/
	static int rtc_update_alarm(struct device dev, struct rtc_time alrm)
	{
	struct rtc_time alarm_tm, now_tm;
	unsigned long now, time;
	int ret;
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	now = get_alarm_or_time(dev, MXC_RTC_TIME);
	rtc_time_to_tm(now, &now_tm);
	alarm_tm.tm_year = now_tm.tm_year;
	alarm_tm.tm_mon = now_tm.tm_mon;
	alarm_tm.tm_mday = now_tm.tm_mday;
	alarm_tm.tm_hour = alrm->tm_hour;
	alarm_tm.tm_min = alrm->tm_min;
	alarm_tm.tm_sec = alrm->tm_sec;
	rtc_tm_to_time(&now_tm, &now);
	rtc_tm_to_time(&alarm_tm, &time);

	if (time < now) {
	time += 60 * 60 * 24;
	rtc_time_to_tm(time, &alarm_tm);
	}

	ret = rtc_tm_to_time(&alarm_tm, &time);

	/* clear all the interrupt status bits */
	writew(readw(ioaddr + RTC_RTCISR), ioaddr + RTC_RTCISR);
	set_alarm_or_time(dev, MXC_RTC_ALARM, time);

	return ret;
	}

	/* This function is the RTC interrupt service routine. */
	static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
	{
	struct platform_device *pdev = dev_id;
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 status;
	u32 events = 0;

	spin_lock_irq(&pdata->rtc->irq_lock);
	status = readw(ioaddr + RTC_RTCISR) & readw(ioaddr + RTC_RTCIENR);
	/* clear interrupt sources */
	writew(status, ioaddr + RTC_RTCISR);

	/* clear alarm interrupt if it has occurred */
	if (status & RTC_ALM_BIT)
	status &= ~RTC_ALM_BIT;

	/* update irq data & counter */
	if (status & RTC_ALM_BIT)
	events \|= (RTC_AF \| RTC_IRQF);

	if (status & RTC_1HZ_BIT)
	events \|= (RTC_UF \| RTC_IRQF);

	if (status & PIT_ALL_ON)
	events \|= (RTC_PF \| RTC_IRQF);

	if ((status & RTC_ALM_BIT) && rtc_valid_tm(&pdata->g_rtc_alarm))
	rtc_update_alarm(&pdev->dev, &pdata->g_rtc_alarm);

	rtc_update_irq(pdata->rtc, 1, events);
	spin_unlock_irq(&pdata->rtc->irq_lock);

	return IRQ_HANDLED;
	}

	/*
	* Clear all interrupts and release the IRQ
	*/
	static void mxc_rtc_release(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	spin_lock_irq(&pdata->rtc->irq_lock);

	/* Disable all rtc interrupts */
	writew(0, ioaddr + RTC_RTCIENR);

	/* Clear all interrupt status */
	writew(0xffffffff, ioaddr + RTC_RTCISR);

	spin_unlock_irq(&pdata->rtc->irq_lock);
	}

	static void mxc_rtc_irq_enable(struct device *dev, unsigned int bit,
	unsigned int enabled)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 reg;

	spin_lock_irq(&pdata->rtc->irq_lock);
	reg = readw(ioaddr + RTC_RTCIENR);

	if (enabled)
	reg \|= bit;
	else
	reg &= ~bit;

	writew(reg, ioaddr + RTC_RTCIENR);
	spin_unlock_irq(&pdata->rtc->irq_lock);
	}

	static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
	{
	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, enabled);
	return 0;
	}

	static int mxc_rtc_update_irq_enable(struct device *dev, unsigned int enabled)
	{
	mxc_rtc_irq_enable(dev, RTC_1HZ_BIT, enabled);
	return 0;
	}

	/*
	* This function reads the current RTC time into tm in Gregorian date.
	*/
	static int mxc_rtc_read_time(struct device dev, struct rtc_time tm)
	{
	u32 val;

	/* Avoid roll-over from reading the different registers */
	do {
	val = get_alarm_or_time(dev, MXC_RTC_TIME);
	} while (val != get_alarm_or_time(dev, MXC_RTC_TIME));

	rtc_time_to_tm(val, tm);

	return 0;
	}

	/*
	* This function sets the internal RTC time based on tm in Gregorian date.
	*/
	static int mxc_rtc_set_mmss(struct device *dev, unsigned long time)
	{
	/* Avoid roll-over from reading the different registers */
	do {
	set_alarm_or_time(dev, MXC_RTC_TIME, time);
	} while (time != get_alarm_or_time(dev, MXC_RTC_TIME));

	return 0;
	}

	/*
	* This function reads the current alarm value into the passed in 'alrm'
	* argument. It updates the alrm's pending field value based on the whether
	* an alarm interrupt occurs or not.
	*/
	static int mxc_rtc_read_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	rtc_time_to_tm(get_alarm_or_time(dev, MXC_RTC_ALARM), &alrm->time);
	alrm->pending = ((readw(ioaddr + RTC_RTCISR) & RTC_ALM_BIT)) ? 1 : 0;

	return 0;
	}

	/*
	* This function sets the RTC alarm based on passed in alrm.
	*/
	static int mxc_rtc_set_alarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	int ret;

	if (rtc_valid_tm(&alrm->time)) {
	if (alrm->time.tm_sec > 59 \|\|
	alrm->time.tm_hour > 23 \|\|
	alrm->time.tm_min > 59)
	return -EINVAL;

	ret = rtc_update_alarm(dev, &alrm->time);
	} else {
	ret = rtc_valid_tm(&alrm->time);
	if (ret)
	return ret;

	ret = rtc_update_alarm(dev, &alrm->time);
	}

	if (ret)
	return ret;

	memcpy(&pdata->g_rtc_alarm, &alrm->time, sizeof(struct rtc_time));
	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, alrm->enabled);

	return 0;
	}

	/* RTC layer */
	static struct rtc_class_ops mxc_rtc_ops = {
	.release = mxc_rtc_release,
	.read_time = mxc_rtc_read_time,
	.set_mmss = mxc_rtc_set_mmss,
	.read_alarm = mxc_rtc_read_alarm,
	.set_alarm = mxc_rtc_set_alarm,
	.alarm_irq_enable = mxc_rtc_alarm_irq_enable,
	.update_irq_enable = mxc_rtc_update_irq_enable,
	};

	static int __init mxc_rtc_probe(struct platform_device *pdev)
	{
	struct resource *res;
	struct rtc_device *rtc;
	struct rtc_plat_data *pdata = NULL;
	u32 reg;
	unsigned long rate;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENODEV;

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

	if (!devm_request_mem_region(&pdev->dev, res->start,
	resource_size(res), pdev->name))
	return -EBUSY;

	pdata->ioaddr = devm_ioremap(&pdev->dev, res->start,
	resource_size(res));

	pdata->clk = clk_get(&pdev->dev, "rtc");
	if (IS_ERR(pdata->clk)) {
	dev_err(&pdev->dev, "unable to get clock!\n");
	ret = PTR_ERR(pdata->clk);
	goto exit_free_pdata;
	}

	clk_enable(pdata->clk);
	rate = clk_get_rate(pdata->clk);

	if (rate == 32768)
	reg = RTC_INPUT_CLK_32768HZ;
	else if (rate == 32000)
	reg = RTC_INPUT_CLK_32000HZ;
	else if (rate == 38400)
	reg = RTC_INPUT_CLK_38400HZ;
	else {
	dev_err(&pdev->dev, "rtc clock is not valid (%lu)\n", rate);
	ret = -EINVAL;
	goto exit_put_clk;
	}

	reg \|= RTC_ENABLE_BIT;
	writew(reg, (pdata->ioaddr + RTC_RTCCTL));
	if (((readw(pdata->ioaddr + RTC_RTCCTL)) & RTC_ENABLE_BIT) == 0) {
	dev_err(&pdev->dev, "hardware module can't be enabled!\n");
	ret = -EIO;
	goto exit_put_clk;
	}

	rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
	THIS_MODULE);
	if (IS_ERR(rtc)) {
	ret = PTR_ERR(rtc);
	goto exit_put_clk;
	}

	pdata->rtc = rtc;
	platform_set_drvdata(pdev, pdata);

	/* Configure and enable the RTC */
	pdata->irq = platform_get_irq(pdev, 0);

	if (pdata->irq >= 0 &&
	devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt,
	IRQF_SHARED, pdev->name, pdev) < 0) {
	dev_warn(&pdev->dev, "interrupt not available.\n");
	pdata->irq = -1;
	}

	return 0;

	exit_put_clk:
	clk_disable(pdata->clk);
	clk_put(pdata->clk);

	exit_free_pdata:

	return ret;
	}

	static int __exit mxc_rtc_remove(struct platform_device *pdev)
	{
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	rtc_device_unregister(pdata->rtc);

	clk_disable(pdata->clk);
	clk_put(pdata->clk);
	platform_set_drvdata(pdev, NULL);

	return 0;
	}

	static struct platform_driver mxc_rtc_driver = {
	.driver = {
	.name = "mxc_rtc",
	.owner = THIS_MODULE,
	},
	.remove = __exit_p(mxc_rtc_remove),
	};

	static int __init mxc_rtc_init(void)
	{
	return platform_driver_probe(&mxc_rtc_driver, mxc_rtc_probe);
	}

	static void __exit mxc_rtc_exit(void)
	{
	platform_driver_unregister(&mxc_rtc_driver);
	}

	module_init(mxc_rtc_init);
	module_exit(mxc_rtc_exit);

	MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
	MODULE_DESCRIPTION("RTC driver for Freescale MXC");
	MODULE_LICENSE("GPL");