drivers/rtc/rtc-at91rm9200.c - kernel/msm-4.9 - Gitiles

 /*
  *	Real Time Clock interface for Linux on Atmel AT91RM9200
  *
  *	Copyright (C) 2002 Rick Bronson
  *
  *	Converted to RTC class model by Andrew Victor
  *
  *	Ported to Linux 2.6 by Steven Scholz
  *	Based on s3c2410-rtc.c Simtec Electronics
  *
  *	Based on sa1100-rtc.c by Nils Faerber
  *	Based on rtc.c by Paul Gortmaker
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
  *	as published by the Free Software Foundation; either version
  *	2 of the License, or (at your option) any later version.
  *
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/time.h>
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/interrupt.h>
 #include <linux/ioctl.h>
 #include <linux/completion.h>

 #include <asm/uaccess.h>

 #include <mach/at91_rtc.h>


 #define AT91_RTC_EPOCH		1900UL	/* just like arch/arm/common/rtctime.c */

 static DECLARE_COMPLETION(at91_rtc_updated);
 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;

 /*
  * Decode time/date into rtc_time structure
  */
 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 				struct rtc_time *tm)
 {
 	unsigned int time, date;

 	/* must read twice in case it changes */
 	do {
 		time = at91_sys_read(timereg);
 		date = at91_sys_read(calreg);
 	} while ((time != at91_sys_read(timereg)) ||
 			(date != at91_sys_read(calreg)));

 	tm->tm_sec  = BCD2BIN((time & AT91_RTC_SEC) >> 0);
 	tm->tm_min  = BCD2BIN((time & AT91_RTC_MIN) >> 8);
 	tm->tm_hour = BCD2BIN((time & AT91_RTC_HOUR) >> 16);

 	/*
 	 * The Calendar Alarm register does not have a field for
 	 * the year - so these will return an invalid value.  When an
 	 * alarm is set, at91_alarm_year wille store the current year.
 	 */
 	tm->tm_year  = BCD2BIN(date & AT91_RTC_CENT) * 100;	/* century */
 	tm->tm_year += BCD2BIN((date & AT91_RTC_YEAR) >> 8);	/* year */

 	tm->tm_wday = BCD2BIN((date & AT91_RTC_DAY) >> 21) - 1;	/* day of the week [0-6], Sunday=0 */
 	tm->tm_mon  = BCD2BIN((date & AT91_RTC_MONTH) >> 16) - 1;
 	tm->tm_mday = BCD2BIN((date & AT91_RTC_DATE) >> 24);
 }

 /*
  * Read current time and date in RTC
  */
 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 {
 	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 	tm->tm_year = tm->tm_year - 1900;

 	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 		tm->tm_hour, tm->tm_min, tm->tm_sec);

 	return 0;
 }

 /*
  * Set current time and date in RTC
  */
 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 {
 	unsigned long cr;

 	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 		tm->tm_hour, tm->tm_min, tm->tm_sec);

 	/* Stop Time/Calendar from counting */
 	cr = at91_sys_read(AT91_RTC_CR);
 	at91_sys_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);

 	at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
 	wait_for_completion(&at91_rtc_updated);	/* wait for ACKUPD interrupt */
 	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);

 	at91_sys_write(AT91_RTC_TIMR,
 			  BIN2BCD(tm->tm_sec) << 0
 			| BIN2BCD(tm->tm_min) << 8
 			| BIN2BCD(tm->tm_hour) << 16);

 	at91_sys_write(AT91_RTC_CALR,
 			  BIN2BCD((tm->tm_year + 1900) / 100)	/* century */
 			| BIN2BCD(tm->tm_year % 100) << 8	/* year */
 			| BIN2BCD(tm->tm_mon + 1) << 16		/* tm_mon starts at zero */
 			| BIN2BCD(tm->tm_wday + 1) << 21	/* day of the week [0-6], Sunday=0 */
 			| BIN2BCD(tm->tm_mday) << 24);

 	/* Restart Time/Calendar */
 	cr = at91_sys_read(AT91_RTC_CR);
 	at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));

 	return 0;
 }

 /*
  * Read alarm time and date in RTC
  */
 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rtc_time *tm = &alrm->time;

 	at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 	tm->tm_year = at91_alarm_year - 1900;

 	alrm->enabled = (at91_sys_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
 			? 1 : 0;

 	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 		tm->tm_hour, tm->tm_min, tm->tm_sec);

 	return 0;
 }

 /*
  * Set alarm time and date in RTC
  */
 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct rtc_time tm;

 	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);

 	at91_alarm_year = tm.tm_year;

 	tm.tm_hour = alrm->time.tm_hour;
 	tm.tm_min = alrm->time.tm_min;
 	tm.tm_sec = alrm->time.tm_sec;

 	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 	at91_sys_write(AT91_RTC_TIMALR,
 		  BIN2BCD(tm.tm_sec) << 0
 		| BIN2BCD(tm.tm_min) << 8
 		| BIN2BCD(tm.tm_hour) << 16
 		| AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 	at91_sys_write(AT91_RTC_CALALR,
 		  BIN2BCD(tm.tm_mon + 1) << 16		/* tm_mon starts at zero */
 		| BIN2BCD(tm.tm_mday) << 24
 		| AT91_RTC_DATEEN | AT91_RTC_MTHEN);

 	if (alrm->enabled) {
 		at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 		at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 	}

 	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 		at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 		tm.tm_min, tm.tm_sec);

 	return 0;
 }

 /*
  * Handle commands from user-space
  */
 static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
 			unsigned long arg)
 {
 	int ret = 0;

 	pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);

 	/* important:  scrub old status before enabling IRQs */
 	switch (cmd) {
 	case RTC_AIE_OFF:	/* alarm off */
 		at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 		break;
 	case RTC_AIE_ON:	/* alarm on */
 		at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 		at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 		break;
 	case RTC_UIE_OFF:	/* update off */
 		at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
 		break;
 	case RTC_UIE_ON:	/* update on */
 		at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 		at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
 		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
 	}

 	return ret;
 }

 /*
  * Provide additional RTC information in /proc/driver/rtc
  */
 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 {
 	unsigned long imr = at91_sys_read(AT91_RTC_IMR);

 	seq_printf(seq, "update_IRQ\t: %s\n",
 			(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 	seq_printf(seq, "periodic_IRQ\t: %s\n",
 			(imr & AT91_RTC_SECEV) ? "yes" : "no");

 	return 0;
 }

 /*
  * IRQ handler for the RTC
  */
 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 {
 	struct platform_device *pdev = dev_id;
 	struct rtc_device *rtc = platform_get_drvdata(pdev);
 	unsigned int rtsr;
 	unsigned long events = 0;

 	rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
 	if (rtsr) {		/* this interrupt is shared!  Is it ours? */
 		if (rtsr & AT91_RTC_ALARM)
 			events |= (RTC_AF | RTC_IRQF);
 		if (rtsr & AT91_RTC_SECEV)
 			events |= (RTC_UF | RTC_IRQF);
 		if (rtsr & AT91_RTC_ACKUPD)
 			complete(&at91_rtc_updated);

 		at91_sys_write(AT91_RTC_SCCR, rtsr);	/* clear status reg */

 		rtc_update_irq(rtc, 1, events);

 		pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
 			events >> 8, events & 0x000000FF);

 		return IRQ_HANDLED;
 	}
 	return IRQ_NONE;		/* not handled */
 }

 static const struct rtc_class_ops at91_rtc_ops = {
 	.ioctl		= at91_rtc_ioctl,
 	.read_time	= at91_rtc_readtime,
 	.set_time	= at91_rtc_settime,
 	.read_alarm	= at91_rtc_readalarm,
 	.set_alarm	= at91_rtc_setalarm,
 	.proc		= at91_rtc_proc,
 };

 /*
  * Initialize and install RTC driver
  */
 static int __init at91_rtc_probe(struct platform_device *pdev)
 {
 	struct rtc_device *rtc;
 	int ret;

 	at91_sys_write(AT91_RTC_CR, 0);
 	at91_sys_write(AT91_RTC_MR, 0);		/* 24 hour mode */

 	/* Disable all interrupts */
 	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
 					AT91_RTC_CALEV);

 	ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
 				IRQF_DISABLED | IRQF_SHARED,
 				"at91_rtc", pdev);
 	if (ret) {
 		printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
 				AT91_ID_SYS);
 		return ret;
 	}

 	/* cpu init code should really have flagged this device as
 	 * being wake-capable; if it didn't, do that here.
 	 */
 	if (!device_can_wakeup(&pdev->dev))
 		device_init_wakeup(&pdev->dev, 1);

 	rtc = rtc_device_register(pdev->name, &pdev->dev,
 				&at91_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc)) {
 		free_irq(AT91_ID_SYS, pdev);
 		return PTR_ERR(rtc);
 	}
 	platform_set_drvdata(pdev, rtc);

 	printk(KERN_INFO "AT91 Real Time Clock driver.\n");
 	return 0;
 }

 /*
  * Disable and remove the RTC driver
  */
 static int __exit at91_rtc_remove(struct platform_device *pdev)
 {
 	struct rtc_device *rtc = platform_get_drvdata(pdev);

 	/* Disable all interrupts */
 	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 					AT91_RTC_SECEV | AT91_RTC_TIMEV |
 					AT91_RTC_CALEV);
 	free_irq(AT91_ID_SYS, pdev);

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

 	return 0;
 }

 #ifdef CONFIG_PM

 /* AT91RM9200 RTC Power management control */

 static u32 at91_rtc_imr;

 static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	/* this IRQ is shared with DBGU and other hardware which isn't
 	 * necessarily doing PM like we are...
 	 */
 	at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
 			& (AT91_RTC_ALARM|AT91_RTC_SECEV);
 	if (at91_rtc_imr) {
 		if (device_may_wakeup(&pdev->dev))
 			enable_irq_wake(AT91_ID_SYS);
 		else
 			at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
 	}
 	return 0;
 }

 static int at91_rtc_resume(struct platform_device *pdev)
 {
 	if (at91_rtc_imr) {
 		if (device_may_wakeup(&pdev->dev))
 			disable_irq_wake(AT91_ID_SYS);
 		else
 			at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
 	}
 	return 0;
 }
 #else
 #define at91_rtc_suspend NULL
 #define at91_rtc_resume  NULL
 #endif

 static struct platform_driver at91_rtc_driver = {
 	.remove		= __exit_p(at91_rtc_remove),
 	.suspend	= at91_rtc_suspend,
 	.resume		= at91_rtc_resume,
 	.driver		= {
 		.name	= "at91_rtc",
 		.owner	= THIS_MODULE,
 	},
 };

 static int __init at91_rtc_init(void)
 {
 	return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
 }

 static void __exit at91_rtc_exit(void)
 {
 	platform_driver_unregister(&at91_rtc_driver);
 }

 module_init(at91_rtc_init);
 module_exit(at91_rtc_exit);

 MODULE_AUTHOR("Rick Bronson");
 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:at91_rtc");
	/*
	* Real Time Clock interface for Linux on Atmel AT91RM9200
	*
	* Copyright (C) 2002 Rick Bronson
	*
	* Converted to RTC class model by Andrew Victor
	*
	* Ported to Linux 2.6 by Steven Scholz
	* Based on s3c2410-rtc.c Simtec Electronics
	*
	* Based on sa1100-rtc.c by Nils Faerber
	* Based on rtc.c by Paul Gortmaker
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/platform_device.h>
	#include <linux/time.h>
	#include <linux/rtc.h>
	#include <linux/bcd.h>
	#include <linux/interrupt.h>
	#include <linux/ioctl.h>
	#include <linux/completion.h>

	#include <asm/uaccess.h>

	#include <mach/at91_rtc.h>


	#define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */

	static DECLARE_COMPLETION(at91_rtc_updated);
	static unsigned int at91_alarm_year = AT91_RTC_EPOCH;

	/*
	* Decode time/date into rtc_time structure
	*/
	static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
	struct rtc_time *tm)
	{
	unsigned int time, date;

	/* must read twice in case it changes */
	do {
	time = at91_sys_read(timereg);
	date = at91_sys_read(calreg);
	} while ((time != at91_sys_read(timereg)) \|\|
	(date != at91_sys_read(calreg)));

	tm->tm_sec = BCD2BIN((time & AT91_RTC_SEC) >> 0);
	tm->tm_min = BCD2BIN((time & AT91_RTC_MIN) >> 8);
	tm->tm_hour = BCD2BIN((time & AT91_RTC_HOUR) >> 16);

	/*
	* The Calendar Alarm register does not have a field for
	* the year - so these will return an invalid value. When an
	* alarm is set, at91_alarm_year wille store the current year.
	*/
	tm->tm_year = BCD2BIN(date & AT91_RTC_CENT) * 100; /* century */
	tm->tm_year += BCD2BIN((date & AT91_RTC_YEAR) >> 8); /* year */

	tm->tm_wday = BCD2BIN((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
	tm->tm_mon = BCD2BIN((date & AT91_RTC_MONTH) >> 16) - 1;
	tm->tm_mday = BCD2BIN((date & AT91_RTC_DATE) >> 24);
	}

	/*
	* Read current time and date in RTC
	*/
	static int at91_rtc_readtime(struct device dev, struct rtc_time tm)
	{
	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
	tm->tm_year = tm->tm_year - 1900;

	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
	1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);

	return 0;
	}

	/*
	* Set current time and date in RTC
	*/
	static int at91_rtc_settime(struct device dev, struct rtc_time tm)
	{
	unsigned long cr;

	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
	1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);

	/* Stop Time/Calendar from counting */
	cr = at91_sys_read(AT91_RTC_CR);
	at91_sys_write(AT91_RTC_CR, cr \| AT91_RTC_UPDCAL \| AT91_RTC_UPDTIM);

	at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
	wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);

	at91_sys_write(AT91_RTC_TIMR,
	BIN2BCD(tm->tm_sec) << 0
	\| BIN2BCD(tm->tm_min) << 8
	\| BIN2BCD(tm->tm_hour) << 16);

	at91_sys_write(AT91_RTC_CALR,
	BIN2BCD((tm->tm_year + 1900) / 100) /* century */
	\| BIN2BCD(tm->tm_year % 100) << 8 /* year */
	\| BIN2BCD(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
	\| BIN2BCD(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
	\| BIN2BCD(tm->tm_mday) << 24);

	/* Restart Time/Calendar */
	cr = at91_sys_read(AT91_RTC_CR);
	at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL \| AT91_RTC_UPDTIM));

	return 0;
	}

	/*
	* Read alarm time and date in RTC
	*/
	static int at91_rtc_readalarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rtc_time *tm = &alrm->time;

	at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
	tm->tm_year = at91_alarm_year - 1900;

	alrm->enabled = (at91_sys_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
	? 1 : 0;

	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
	1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
	tm->tm_hour, tm->tm_min, tm->tm_sec);

	return 0;
	}

	/*
	* Set alarm time and date in RTC
	*/
	static int at91_rtc_setalarm(struct device dev, struct rtc_wkalrm alrm)
	{
	struct rtc_time tm;

	at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);

	at91_alarm_year = tm.tm_year;

	tm.tm_hour = alrm->time.tm_hour;
	tm.tm_min = alrm->time.tm_min;
	tm.tm_sec = alrm->time.tm_sec;

	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
	at91_sys_write(AT91_RTC_TIMALR,
	BIN2BCD(tm.tm_sec) << 0
	\| BIN2BCD(tm.tm_min) << 8
	\| BIN2BCD(tm.tm_hour) << 16
	\| AT91_RTC_HOUREN \| AT91_RTC_MINEN \| AT91_RTC_SECEN);
	at91_sys_write(AT91_RTC_CALALR,
	BIN2BCD(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
	\| BIN2BCD(tm.tm_mday) << 24
	\| AT91_RTC_DATEEN \| AT91_RTC_MTHEN);

	if (alrm->enabled) {
	at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
	at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
	}

	pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
	at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
	tm.tm_min, tm.tm_sec);

	return 0;
	}

	/*
	* Handle commands from user-space
	*/
	static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
	unsigned long arg)
	{
	int ret = 0;

	pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);

	/* important: scrub old status before enabling IRQs */
	switch (cmd) {
	case RTC_AIE_OFF: /* alarm off */
	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
	break;
	case RTC_AIE_ON: /* alarm on */
	at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
	at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
	break;
	case RTC_UIE_OFF: /* update off */
	at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
	break;
	case RTC_UIE_ON: /* update on */
	at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
	at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
	break;
	default:
	ret = -ENOIOCTLCMD;
	break;
	}

	return ret;
	}

	/*
	* Provide additional RTC information in /proc/driver/rtc
	*/
	static int at91_rtc_proc(struct device dev, struct seq_file seq)
	{
	unsigned long imr = at91_sys_read(AT91_RTC_IMR);

	seq_printf(seq, "update_IRQ\t: %s\n",
	(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
	seq_printf(seq, "periodic_IRQ\t: %s\n",
	(imr & AT91_RTC_SECEV) ? "yes" : "no");

	return 0;
	}

	/*
	* IRQ handler for the RTC
	*/
	static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
	{
	struct platform_device *pdev = dev_id;
	struct rtc_device *rtc = platform_get_drvdata(pdev);
	unsigned int rtsr;
	unsigned long events = 0;

	rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
	if (rtsr) { /* this interrupt is shared! Is it ours? */
	if (rtsr & AT91_RTC_ALARM)
	events \|= (RTC_AF \| RTC_IRQF);
	if (rtsr & AT91_RTC_SECEV)
	events \|= (RTC_UF \| RTC_IRQF);
	if (rtsr & AT91_RTC_ACKUPD)
	complete(&at91_rtc_updated);

	at91_sys_write(AT91_RTC_SCCR, rtsr); /* clear status reg */

	rtc_update_irq(rtc, 1, events);

	pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
	events >> 8, events & 0x000000FF);

	return IRQ_HANDLED;
	}
	return IRQ_NONE; /* not handled */
	}

	static const struct rtc_class_ops at91_rtc_ops = {
	.ioctl = at91_rtc_ioctl,
	.read_time = at91_rtc_readtime,
	.set_time = at91_rtc_settime,
	.read_alarm = at91_rtc_readalarm,
	.set_alarm = at91_rtc_setalarm,
	.proc = at91_rtc_proc,
	};

	/*
	* Initialize and install RTC driver
	*/
	static int __init at91_rtc_probe(struct platform_device *pdev)
	{
	struct rtc_device *rtc;
	int ret;

	at91_sys_write(AT91_RTC_CR, 0);
	at91_sys_write(AT91_RTC_MR, 0); /* 24 hour mode */

	/* Disable all interrupts */
	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD \| AT91_RTC_ALARM \|
	AT91_RTC_SECEV \| AT91_RTC_TIMEV \|
	AT91_RTC_CALEV);

	ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
	IRQF_DISABLED \| IRQF_SHARED,
	"at91_rtc", pdev);
	if (ret) {
	printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
	AT91_ID_SYS);
	return ret;
	}

	/* cpu init code should really have flagged this device as
	* being wake-capable; if it didn't, do that here.
	*/
	if (!device_can_wakeup(&pdev->dev))
	device_init_wakeup(&pdev->dev, 1);

	rtc = rtc_device_register(pdev->name, &pdev->dev,
	&at91_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc)) {
	free_irq(AT91_ID_SYS, pdev);
	return PTR_ERR(rtc);
	}
	platform_set_drvdata(pdev, rtc);

	printk(KERN_INFO "AT91 Real Time Clock driver.\n");
	return 0;
	}

	/*
	* Disable and remove the RTC driver
	*/
	static int __exit at91_rtc_remove(struct platform_device *pdev)
	{
	struct rtc_device *rtc = platform_get_drvdata(pdev);

	/* Disable all interrupts */
	at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD \| AT91_RTC_ALARM \|
	AT91_RTC_SECEV \| AT91_RTC_TIMEV \|
	AT91_RTC_CALEV);
	free_irq(AT91_ID_SYS, pdev);

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

	return 0;
	}

	#ifdef CONFIG_PM

	/* AT91RM9200 RTC Power management control */

	static u32 at91_rtc_imr;

	static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state)
	{
	/* this IRQ is shared with DBGU and other hardware which isn't
	* necessarily doing PM like we are...
	*/
	at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
	& (AT91_RTC_ALARM\|AT91_RTC_SECEV);
	if (at91_rtc_imr) {
	if (device_may_wakeup(&pdev->dev))
	enable_irq_wake(AT91_ID_SYS);
	else
	at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
	}
	return 0;
	}

	static int at91_rtc_resume(struct platform_device *pdev)
	{
	if (at91_rtc_imr) {
	if (device_may_wakeup(&pdev->dev))
	disable_irq_wake(AT91_ID_SYS);
	else
	at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
	}
	return 0;
	}
	#else
	#define at91_rtc_suspend NULL
	#define at91_rtc_resume NULL
	#endif

	static struct platform_driver at91_rtc_driver = {
	.remove = __exit_p(at91_rtc_remove),
	.suspend = at91_rtc_suspend,
	.resume = at91_rtc_resume,
	.driver = {
	.name = "at91_rtc",
	.owner = THIS_MODULE,
	},
	};

	static int __init at91_rtc_init(void)
	{
	return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
	}

	static void __exit at91_rtc_exit(void)
	{
	platform_driver_unregister(&at91_rtc_driver);
	}

	module_init(at91_rtc_init);
	module_exit(at91_rtc_exit);

	MODULE_AUTHOR("Rick Bronson");
	MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:at91_rtc");