drivers/char/vr41xx_rtc.c - kernel/msm-4.9 - Gitiles

 /*
  *  Driver for NEC VR4100 series  Real Time Clock unit.
  *
  *  Copyright (C) 2003-2005  Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
  *
  *  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.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 #include <linux/platform_device.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
 #include <linux/mc146818rtc.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/poll.h>
 #include <linux/rtc.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>

 #include <asm/div64.h>
 #include <asm/io.h>
 #include <asm/time.h>
 #include <asm/uaccess.h>
 #include <asm/vr41xx/vr41xx.h>

 MODULE_AUTHOR("Yoichi Yuasa <yuasa@hh.iij4u.or.jp>");
 MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
 MODULE_LICENSE("GPL");

 #define RTC1_TYPE1_START	0x0b0000c0UL
 #define RTC1_TYPE1_END		0x0b0000dfUL
 #define RTC2_TYPE1_START	0x0b0001c0UL
 #define RTC2_TYPE1_END		0x0b0001dfUL

 #define RTC1_TYPE2_START	0x0f000100UL
 #define RTC1_TYPE2_END		0x0f00011fUL
 #define RTC2_TYPE2_START	0x0f000120UL
 #define RTC2_TYPE2_END		0x0f00013fUL

 #define RTC1_SIZE		0x20
 #define RTC2_SIZE		0x20

 /* RTC 1 registers */
 #define ETIMELREG		0x00
 #define ETIMEMREG		0x02
 #define ETIMEHREG		0x04
 /* RFU */
 #define ECMPLREG		0x08
 #define ECMPMREG		0x0a
 #define ECMPHREG		0x0c
 /* RFU */
 #define RTCL1LREG		0x10
 #define RTCL1HREG		0x12
 #define RTCL1CNTLREG		0x14
 #define RTCL1CNTHREG		0x16
 #define RTCL2LREG		0x18
 #define RTCL2HREG		0x1a
 #define RTCL2CNTLREG		0x1c
 #define RTCL2CNTHREG		0x1e

 /* RTC 2 registers */
 #define TCLKLREG		0x00
 #define TCLKHREG		0x02
 #define TCLKCNTLREG		0x04
 #define TCLKCNTHREG		0x06
 /* RFU */
 #define RTCINTREG		0x1e
  #define TCLOCK_INT		0x08
  #define RTCLONG2_INT		0x04
  #define RTCLONG1_INT		0x02
  #define ELAPSEDTIME_INT	0x01

 #define RTC_FREQUENCY		32768
 #define MAX_PERIODIC_RATE	6553
 #define MAX_USER_PERIODIC_RATE	64

 static void __iomem *rtc1_base;
 static void __iomem *rtc2_base;

 #define rtc1_read(offset)		readw(rtc1_base + (offset))
 #define rtc1_write(offset, value)	writew((value), rtc1_base + (offset))

 #define rtc2_read(offset)		readw(rtc2_base + (offset))
 #define rtc2_write(offset, value)	writew((value), rtc2_base + (offset))

 static unsigned long epoch = 1970;	/* Jan 1 1970 00:00:00 */

 static spinlock_t rtc_task_lock;
 static wait_queue_head_t rtc_wait;
 static unsigned long rtc_irq_data;
 static struct fasync_struct *rtc_async_queue;
 static rtc_task_t *rtc_callback;
 static char rtc_name[] = "RTC";
 static unsigned long periodic_frequency;
 static unsigned long periodic_count;

 typedef enum {
 	RTC_RELEASE,
 	RTC_OPEN,
 } rtc_status_t;

 static rtc_status_t rtc_status;

 typedef enum {
 	FUNCTION_RTC_IOCTL,
 	FUNCTION_RTC_CONTROL,
 } rtc_callfrom_t;

 struct resource rtc_resource[2] = {
 	{	.name	= rtc_name,
 		.flags	= IORESOURCE_MEM,	},
 	{	.name	= rtc_name,
 		.flags	= IORESOURCE_MEM,	},
 };

 #define RTC_NUM_RESOURCES	sizeof(rtc_resource) / sizeof(struct resource)

 static inline unsigned long read_elapsed_second(void)
 {
 	unsigned long first_low, first_mid, first_high;
 	unsigned long second_low, second_mid, second_high;

 	do {
 		first_low = rtc1_read(ETIMELREG);
 		first_mid = rtc1_read(ETIMEMREG);
 		first_high = rtc1_read(ETIMEHREG);
 		second_low = rtc1_read(ETIMELREG);
 		second_mid = rtc1_read(ETIMEMREG);
 		second_high = rtc1_read(ETIMEHREG);
 	} while (first_low != second_low || first_mid != second_mid ||
 	         first_high != second_high);

 	return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
 }

 static inline void write_elapsed_second(unsigned long sec)
 {
 	spin_lock_irq(&rtc_lock);

 	rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
 	rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
 	rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));

 	spin_unlock_irq(&rtc_lock);
 }

 static void set_alarm(struct rtc_time *time)
 {
 	unsigned long alarm_sec;

 	alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 	                   time->tm_hour, time->tm_min, time->tm_sec);

 	spin_lock_irq(&rtc_lock);

 	rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
 	rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
 	rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));

 	spin_unlock_irq(&rtc_lock);
 }

 static void read_alarm(struct rtc_time *time)
 {
 	unsigned long low, mid, high;

 	spin_lock_irq(&rtc_lock);

 	low = rtc1_read(ECMPLREG);
 	mid = rtc1_read(ECMPMREG);
 	high = rtc1_read(ECMPHREG);

 	spin_unlock_irq(&rtc_lock);

 	to_tm((high << 17) | (mid << 1) | (low >> 15), time);
 	time->tm_year -= 1900;
 }

 static void read_time(struct rtc_time *time)
 {
 	unsigned long epoch_sec, elapsed_sec;

 	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 	elapsed_sec = read_elapsed_second();

 	to_tm(epoch_sec + elapsed_sec, time);
 	time->tm_year -= 1900;
 }

 static void set_time(struct rtc_time *time)
 {
 	unsigned long epoch_sec, current_sec;

 	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 	current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 	                     time->tm_hour, time->tm_min, time->tm_sec);

 	write_elapsed_second(current_sec - epoch_sec);
 }

 static ssize_t rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	DECLARE_WAITQUEUE(wait, current);
 	unsigned long irq_data;
 	int retval = 0;

 	if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
 		return -EINVAL;

 	add_wait_queue(&rtc_wait, &wait);

 	do {
 		__set_current_state(TASK_INTERRUPTIBLE);

 		spin_lock_irq(&rtc_lock);
 		irq_data = rtc_irq_data;
 		rtc_irq_data = 0;
 		spin_unlock_irq(&rtc_lock);

 		if (irq_data != 0)
 			break;

 		if (file->f_flags & O_NONBLOCK) {
 			retval = -EAGAIN;
 			break;
 		}

 		if (signal_pending(current)) {
 			retval = -ERESTARTSYS;
 			break;
 		}
 	} while (1);

 	if (retval == 0) {
 		if (count == sizeof(unsigned int)) {
 			retval = put_user(irq_data, (unsigned int __user *)buf);
 			if (retval == 0)
 				retval = sizeof(unsigned int);
 		} else {
 			retval = put_user(irq_data, (unsigned long __user *)buf);
 			if (retval == 0)
 				retval = sizeof(unsigned long);
 		}

 	}

 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&rtc_wait, &wait);

 	return retval;
 }

 static unsigned int rtc_poll(struct file *file, struct poll_table_struct *table)
 {
 	poll_wait(file, &rtc_wait, table);

 	if (rtc_irq_data != 0)
 		return POLLIN | POLLRDNORM;

 	return 0;
 }

 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, rtc_callfrom_t from)
 {
 	struct rtc_time time;
 	unsigned long count;

 	switch (cmd) {
 	case RTC_AIE_ON:
 		enable_irq(ELAPSEDTIME_IRQ);
 		break;
 	case RTC_AIE_OFF:
 		disable_irq(ELAPSEDTIME_IRQ);
 		break;
 	case RTC_PIE_ON:
 		enable_irq(RTCLONG1_IRQ);
 		break;
 	case RTC_PIE_OFF:
 		disable_irq(RTCLONG1_IRQ);
 		break;
 	case RTC_ALM_SET:
 		if (copy_from_user(&time, (struct rtc_time __user *)arg,
 		                   sizeof(struct rtc_time)))
 			return -EFAULT;

 		set_alarm(&time);
 		break;
 	case RTC_ALM_READ:
 		memset(&time, 0, sizeof(struct rtc_time));
 		read_alarm(&time);
 		break;
 	case RTC_RD_TIME:
 		memset(&time, 0, sizeof(struct rtc_time));
 		read_time(&time);
 		if (copy_to_user((void __user *)arg, &time, sizeof(struct rtc_time)))
 			return -EFAULT;
 		break;
 	case RTC_SET_TIME:
 		if (capable(CAP_SYS_TIME) == 0)
 			return -EACCES;

 		if (copy_from_user(&time, (struct rtc_time __user *)arg,
 		                   sizeof(struct rtc_time)))
 			return -EFAULT;

 		set_time(&time);
 		break;
 	case RTC_IRQP_READ:
 		return put_user(periodic_frequency, (unsigned long __user *)arg);
 		break;
 	case RTC_IRQP_SET:
 		if (arg > MAX_PERIODIC_RATE)
 			return -EINVAL;

 		if (from == FUNCTION_RTC_IOCTL && arg > MAX_USER_PERIODIC_RATE &&
 		    capable(CAP_SYS_RESOURCE) == 0)
 			return -EACCES;

 		periodic_frequency = arg;

 		count = RTC_FREQUENCY;
 		do_div(count, arg);

 		periodic_count = count;

 		spin_lock_irq(&rtc_lock);

 		rtc1_write(RTCL1LREG, count);
 		rtc1_write(RTCL1HREG, count >> 16);

 		spin_unlock_irq(&rtc_lock);
 		break;
 	case RTC_EPOCH_READ:
 		return put_user(epoch, (unsigned long __user *)arg);
 	case RTC_EPOCH_SET:
 		/* Doesn't support before 1900 */
 		if (arg < 1900)
 			return -EINVAL;

 		if (capable(CAP_SYS_TIME) == 0)
 			return -EACCES;

 		epoch = arg;
 		break;
 	default:
 		return -EINVAL;
 	}

 	return 0;
 }

 static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
                      unsigned long arg)
 {
 	return rtc_do_ioctl(cmd, arg, FUNCTION_RTC_IOCTL);
 }

 static int rtc_open(struct inode *inode, struct file *file)
 {
 	spin_lock_irq(&rtc_lock);

 	if (rtc_status == RTC_OPEN) {
 		spin_unlock_irq(&rtc_lock);
 		return -EBUSY;
 	}

 	rtc_status = RTC_OPEN;
 	rtc_irq_data = 0;

 	spin_unlock_irq(&rtc_lock);

 	return 0;
 }

 static int rtc_release(struct inode *inode, struct file *file)
 {
 	if (file->f_flags & FASYNC)
 		(void)fasync_helper(-1, file, 0, &rtc_async_queue);

 	spin_lock_irq(&rtc_lock);

 	rtc1_write(ECMPLREG, 0);
 	rtc1_write(ECMPMREG, 0);
 	rtc1_write(ECMPHREG, 0);
 	rtc1_write(RTCL1LREG, 0);
 	rtc1_write(RTCL1HREG, 0);

 	rtc_status = RTC_RELEASE;

 	spin_unlock_irq(&rtc_lock);

 	disable_irq(ELAPSEDTIME_IRQ);
 	disable_irq(RTCLONG1_IRQ);

 	return 0;
 }

 static int rtc_fasync(int fd, struct file *file, int on)
 {
 	return fasync_helper(fd, file, on, &rtc_async_queue);
 }

 static struct file_operations rtc_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.read		= rtc_read,
 	.poll		= rtc_poll,
 	.ioctl		= rtc_ioctl,
 	.open		= rtc_open,
 	.release	= rtc_release,
 	.fasync		= rtc_fasync,
 };

 static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
 	spin_lock(&rtc_lock);
 	rtc2_write(RTCINTREG, ELAPSEDTIME_INT);

 	rtc_irq_data += 0x100;
 	rtc_irq_data &= ~0xff;
 	rtc_irq_data |= RTC_AF;
 	spin_unlock(&rtc_lock);

 	spin_lock(&rtc_lock);
 	if (rtc_callback)
 		rtc_callback->func(rtc_callback->private_data);
 	spin_unlock(&rtc_lock);

 	wake_up_interruptible(&rtc_wait);

 	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

 	return IRQ_HANDLED;
 }

 static irqreturn_t rtclong1_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
 	unsigned long count = periodic_count;

 	spin_lock(&rtc_lock);
 	rtc2_write(RTCINTREG, RTCLONG1_INT);

 	rtc1_write(RTCL1LREG, count);
 	rtc1_write(RTCL1HREG, count >> 16);

 	rtc_irq_data += 0x100;
 	rtc_irq_data &= ~0xff;
 	rtc_irq_data |= RTC_PF;
 	spin_unlock(&rtc_lock);

 	spin_lock(&rtc_task_lock);
 	if (rtc_callback)
 		rtc_callback->func(rtc_callback->private_data);
 	spin_unlock(&rtc_task_lock);

 	wake_up_interruptible(&rtc_wait);

 	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

 	return IRQ_HANDLED;
 }

 int rtc_register(rtc_task_t *task)
 {
 	if (task == NULL || task->func == NULL)
 		return -EINVAL;

 	spin_lock_irq(&rtc_lock);
 	if (rtc_status == RTC_OPEN) {
 		spin_unlock_irq(&rtc_lock);
 		return -EBUSY;
 	}

 	spin_lock(&rtc_task_lock);
 	if (rtc_callback != NULL) {
 		spin_unlock(&rtc_task_lock);
 		spin_unlock_irq(&rtc_task_lock);
 		return -EBUSY;
 	}

 	rtc_callback = task;
 	spin_unlock(&rtc_task_lock);

 	rtc_status = RTC_OPEN;

 	spin_unlock_irq(&rtc_lock);

 	return 0;
 }

 EXPORT_SYMBOL_GPL(rtc_register);

 int rtc_unregister(rtc_task_t *task)
 {
 	spin_lock_irq(&rtc_task_lock);
 	if (task == NULL || rtc_callback != task) {
 		spin_unlock_irq(&rtc_task_lock);
 		return -ENXIO;
 	}

 	spin_lock(&rtc_lock);

 	rtc1_write(ECMPLREG, 0);
 	rtc1_write(ECMPMREG, 0);
 	rtc1_write(ECMPHREG, 0);
 	rtc1_write(RTCL1LREG, 0);
 	rtc1_write(RTCL1HREG, 0);

 	rtc_status = RTC_RELEASE;

 	spin_unlock(&rtc_lock);

 	rtc_callback = NULL;

 	spin_unlock_irq(&rtc_task_lock);

 	disable_irq(ELAPSEDTIME_IRQ);
 	disable_irq(RTCLONG1_IRQ);

 	return 0;
 }

 EXPORT_SYMBOL_GPL(rtc_unregister);

 int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
 {
 	int retval = 0;

 	spin_lock_irq(&rtc_task_lock);

 	if (rtc_callback != task)
 		retval = -ENXIO;
 	else
 		rtc_do_ioctl(cmd, arg, FUNCTION_RTC_CONTROL);

 	spin_unlock_irq(&rtc_task_lock);

 	return retval;
 }

 EXPORT_SYMBOL_GPL(rtc_control);

 static struct miscdevice rtc_miscdevice = {
 	.minor	= RTC_MINOR,
 	.name	= rtc_name,
 	.fops	= &rtc_fops,
 };

 static int rtc_probe(struct device *dev)
 {
 	struct platform_device *pdev;
 	unsigned int irq;
 	int retval;

 	pdev = to_platform_device(dev);
 	if (pdev->num_resources != 2)
 		return -EBUSY;

 	rtc1_base = ioremap(pdev->resource[0].start, RTC1_SIZE);
 	if (rtc1_base == NULL)
 		return -EBUSY;

 	rtc2_base = ioremap(pdev->resource[1].start, RTC2_SIZE);
 	if (rtc2_base == NULL) {
 		iounmap(rtc1_base);
 		rtc1_base = NULL;
 		return -EBUSY;
 	}

 	retval = misc_register(&rtc_miscdevice);
 	if (retval < 0) {
 		iounmap(rtc1_base);
 		iounmap(rtc2_base);
 		rtc1_base = NULL;
 		rtc2_base = NULL;
 		return retval;
 	}

 	spin_lock_irq(&rtc_lock);

 	rtc1_write(ECMPLREG, 0);
 	rtc1_write(ECMPMREG, 0);
 	rtc1_write(ECMPHREG, 0);
 	rtc1_write(RTCL1LREG, 0);
 	rtc1_write(RTCL1HREG, 0);

 	rtc_status = RTC_RELEASE;
 	rtc_irq_data = 0;

 	spin_unlock_irq(&rtc_lock);

 	init_waitqueue_head(&rtc_wait);

 	irq = ELAPSEDTIME_IRQ;
 	retval = request_irq(irq, elapsedtime_interrupt, SA_INTERRUPT,
 	                     "elapsed_time", NULL);
 	if (retval == 0) {
 		irq = RTCLONG1_IRQ;
 		retval = request_irq(irq, rtclong1_interrupt, SA_INTERRUPT,
 		                     "rtclong1", NULL);
 	}

 	if (retval < 0) {
 		printk(KERN_ERR "rtc: IRQ%d is busy\n", irq);
 		if (irq == RTCLONG1_IRQ)
 			free_irq(ELAPSEDTIME_IRQ, NULL);
 		iounmap(rtc1_base);
 		iounmap(rtc2_base);
 		rtc1_base = NULL;
 		rtc2_base = NULL;
 		return retval;
 	}

 	disable_irq(ELAPSEDTIME_IRQ);
 	disable_irq(RTCLONG1_IRQ);

 	spin_lock_init(&rtc_task_lock);

 	printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");

 	return 0;
 }

 static int rtc_remove(struct device *dev)
 {
 	int retval;

 	retval = misc_deregister(&rtc_miscdevice);
 	if (retval < 0)
 		return retval;

 	free_irq(ELAPSEDTIME_IRQ, NULL);
 	free_irq(RTCLONG1_IRQ, NULL);
 	if (rtc1_base != NULL)
 		iounmap(rtc1_base);
 	if (rtc2_base != NULL)
 		iounmap(rtc2_base);

 	return 0;
 }

 static struct platform_device *rtc_platform_device;

 static struct device_driver rtc_device_driver = {
 	.name		= rtc_name,
 	.bus		= &platform_bus_type,
 	.probe		= rtc_probe,
 	.remove		= rtc_remove,
 };

 static int __devinit vr41xx_rtc_init(void)
 {
 	int retval;

 	switch (current_cpu_data.cputype) {
 	case CPU_VR4111:
 	case CPU_VR4121:
 		rtc_resource[0].start = RTC1_TYPE1_START;
 		rtc_resource[0].end = RTC1_TYPE1_END;
 		rtc_resource[1].start = RTC2_TYPE1_START;
 		rtc_resource[1].end = RTC2_TYPE1_END;
 		break;
 	case CPU_VR4122:
 	case CPU_VR4131:
 	case CPU_VR4133:
 		rtc_resource[0].start = RTC1_TYPE2_START;
 		rtc_resource[0].end = RTC1_TYPE2_END;
 		rtc_resource[1].start = RTC2_TYPE2_START;
 		rtc_resource[1].end = RTC2_TYPE2_END;
 		break;
 	default:
 		return -ENODEV;
 		break;
 	}

 	rtc_platform_device = platform_device_register_simple("RTC", -1, rtc_resource, RTC_NUM_RESOURCES);
 	if (IS_ERR(rtc_platform_device))
 		return PTR_ERR(rtc_platform_device);

 	retval = driver_register(&rtc_device_driver);
 	if (retval < 0)
 		platform_device_unregister(rtc_platform_device);

 	return retval;
 }

 static void __devexit vr41xx_rtc_exit(void)
 {
 	driver_unregister(&rtc_device_driver);

 	platform_device_unregister(rtc_platform_device);
 }

 module_init(vr41xx_rtc_init);
 module_exit(vr41xx_rtc_exit);
	/*
	* Driver for NEC VR4100 series Real Time Clock unit.
	*
	* Copyright (C) 2003-2005 Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
	*
	* 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.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/
	#include <linux/platform_device.h>
	#include <linux/fs.h>
	#include <linux/init.h>
	#include <linux/ioport.h>
	#include <linux/irq.h>
	#include <linux/mc146818rtc.h>
	#include <linux/miscdevice.h>
	#include <linux/module.h>
	#include <linux/poll.h>
	#include <linux/rtc.h>
	#include <linux/spinlock.h>
	#include <linux/types.h>
	#include <linux/wait.h>

	#include <asm/div64.h>
	#include <asm/io.h>
	#include <asm/time.h>
	#include <asm/uaccess.h>
	#include <asm/vr41xx/vr41xx.h>

	MODULE_AUTHOR("Yoichi Yuasa <yuasa@hh.iij4u.or.jp>");
	MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
	MODULE_LICENSE("GPL");

	#define RTC1_TYPE1_START 0x0b0000c0UL
	#define RTC1_TYPE1_END 0x0b0000dfUL
	#define RTC2_TYPE1_START 0x0b0001c0UL
	#define RTC2_TYPE1_END 0x0b0001dfUL

	#define RTC1_TYPE2_START 0x0f000100UL
	#define RTC1_TYPE2_END 0x0f00011fUL
	#define RTC2_TYPE2_START 0x0f000120UL
	#define RTC2_TYPE2_END 0x0f00013fUL

	#define RTC1_SIZE 0x20
	#define RTC2_SIZE 0x20

	/* RTC 1 registers */
	#define ETIMELREG 0x00
	#define ETIMEMREG 0x02
	#define ETIMEHREG 0x04
	/* RFU */
	#define ECMPLREG 0x08
	#define ECMPMREG 0x0a
	#define ECMPHREG 0x0c
	/* RFU */
	#define RTCL1LREG 0x10
	#define RTCL1HREG 0x12
	#define RTCL1CNTLREG 0x14
	#define RTCL1CNTHREG 0x16
	#define RTCL2LREG 0x18
	#define RTCL2HREG 0x1a
	#define RTCL2CNTLREG 0x1c
	#define RTCL2CNTHREG 0x1e

	/* RTC 2 registers */
	#define TCLKLREG 0x00
	#define TCLKHREG 0x02
	#define TCLKCNTLREG 0x04
	#define TCLKCNTHREG 0x06
	/* RFU */
	#define RTCINTREG 0x1e
	#define TCLOCK_INT 0x08
	#define RTCLONG2_INT 0x04
	#define RTCLONG1_INT 0x02
	#define ELAPSEDTIME_INT 0x01

	#define RTC_FREQUENCY 32768
	#define MAX_PERIODIC_RATE 6553
	#define MAX_USER_PERIODIC_RATE 64

	static void __iomem *rtc1_base;
	static void __iomem *rtc2_base;

	#define rtc1_read(offset) readw(rtc1_base + (offset))
	#define rtc1_write(offset, value) writew((value), rtc1_base + (offset))

	#define rtc2_read(offset) readw(rtc2_base + (offset))
	#define rtc2_write(offset, value) writew((value), rtc2_base + (offset))

	static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */

	static spinlock_t rtc_task_lock;
	static wait_queue_head_t rtc_wait;
	static unsigned long rtc_irq_data;
	static struct fasync_struct *rtc_async_queue;
	static rtc_task_t *rtc_callback;
	static char rtc_name[] = "RTC";
	static unsigned long periodic_frequency;
	static unsigned long periodic_count;

	typedef enum {
	RTC_RELEASE,
	RTC_OPEN,
	} rtc_status_t;

	static rtc_status_t rtc_status;

	typedef enum {
	FUNCTION_RTC_IOCTL,
	FUNCTION_RTC_CONTROL,
	} rtc_callfrom_t;

	struct resource rtc_resource[2] = {
	{ .name = rtc_name,
	.flags = IORESOURCE_MEM, },
	{ .name = rtc_name,
	.flags = IORESOURCE_MEM, },
	};

	#define RTC_NUM_RESOURCES sizeof(rtc_resource) / sizeof(struct resource)

	static inline unsigned long read_elapsed_second(void)
	{
	unsigned long first_low, first_mid, first_high;
	unsigned long second_low, second_mid, second_high;

	do {
	first_low = rtc1_read(ETIMELREG);
	first_mid = rtc1_read(ETIMEMREG);
	first_high = rtc1_read(ETIMEHREG);
	second_low = rtc1_read(ETIMELREG);
	second_mid = rtc1_read(ETIMEMREG);
	second_high = rtc1_read(ETIMEHREG);
	} while (first_low != second_low \|\| first_mid != second_mid \|\|
	first_high != second_high);

	return (first_high << 17) \| (first_mid << 1) \| (first_low >> 15);
	}

	static inline void write_elapsed_second(unsigned long sec)
	{
	spin_lock_irq(&rtc_lock);

	rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
	rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
	rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));

	spin_unlock_irq(&rtc_lock);
	}

	static void set_alarm(struct rtc_time *time)
	{
	unsigned long alarm_sec;

	alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
	time->tm_hour, time->tm_min, time->tm_sec);

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
	rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
	rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));

	spin_unlock_irq(&rtc_lock);
	}

	static void read_alarm(struct rtc_time *time)
	{
	unsigned long low, mid, high;

	spin_lock_irq(&rtc_lock);

	low = rtc1_read(ECMPLREG);
	mid = rtc1_read(ECMPMREG);
	high = rtc1_read(ECMPHREG);

	spin_unlock_irq(&rtc_lock);

	to_tm((high << 17) \| (mid << 1) \| (low >> 15), time);
	time->tm_year -= 1900;
	}

	static void read_time(struct rtc_time *time)
	{
	unsigned long epoch_sec, elapsed_sec;

	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
	elapsed_sec = read_elapsed_second();

	to_tm(epoch_sec + elapsed_sec, time);
	time->tm_year -= 1900;
	}

	static void set_time(struct rtc_time *time)
	{
	unsigned long epoch_sec, current_sec;

	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
	current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
	time->tm_hour, time->tm_min, time->tm_sec);

	write_elapsed_second(current_sec - epoch_sec);
	}

	static ssize_t rtc_read(struct file file, char __user buf, size_t count, loff_t *ppos)
	{
	DECLARE_WAITQUEUE(wait, current);
	unsigned long irq_data;
	int retval = 0;

	if (count != sizeof(unsigned int) && count != sizeof(unsigned long))
	return -EINVAL;

	add_wait_queue(&rtc_wait, &wait);

	do {
	__set_current_state(TASK_INTERRUPTIBLE);

	spin_lock_irq(&rtc_lock);
	irq_data = rtc_irq_data;
	rtc_irq_data = 0;
	spin_unlock_irq(&rtc_lock);

	if (irq_data != 0)
	break;

	if (file->f_flags & O_NONBLOCK) {
	retval = -EAGAIN;
	break;
	}

	if (signal_pending(current)) {
	retval = -ERESTARTSYS;
	break;
	}
	} while (1);

	if (retval == 0) {
	if (count == sizeof(unsigned int)) {
	retval = put_user(irq_data, (unsigned int __user *)buf);
	if (retval == 0)
	retval = sizeof(unsigned int);
	} else {
	retval = put_user(irq_data, (unsigned long __user *)buf);
	if (retval == 0)
	retval = sizeof(unsigned long);
	}

	}

	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&rtc_wait, &wait);

	return retval;
	}

	static unsigned int rtc_poll(struct file file, struct poll_table_struct table)
	{
	poll_wait(file, &rtc_wait, table);

	if (rtc_irq_data != 0)
	return POLLIN \| POLLRDNORM;

	return 0;
	}

	static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, rtc_callfrom_t from)
	{
	struct rtc_time time;
	unsigned long count;

	switch (cmd) {
	case RTC_AIE_ON:
	enable_irq(ELAPSEDTIME_IRQ);
	break;
	case RTC_AIE_OFF:
	disable_irq(ELAPSEDTIME_IRQ);
	break;
	case RTC_PIE_ON:
	enable_irq(RTCLONG1_IRQ);
	break;
	case RTC_PIE_OFF:
	disable_irq(RTCLONG1_IRQ);
	break;
	case RTC_ALM_SET:
	if (copy_from_user(&time, (struct rtc_time __user *)arg,
	sizeof(struct rtc_time)))
	return -EFAULT;

	set_alarm(&time);
	break;
	case RTC_ALM_READ:
	memset(&time, 0, sizeof(struct rtc_time));
	read_alarm(&time);
	break;
	case RTC_RD_TIME:
	memset(&time, 0, sizeof(struct rtc_time));
	read_time(&time);
	if (copy_to_user((void __user *)arg, &time, sizeof(struct rtc_time)))
	return -EFAULT;
	break;
	case RTC_SET_TIME:
	if (capable(CAP_SYS_TIME) == 0)
	return -EACCES;

	if (copy_from_user(&time, (struct rtc_time __user *)arg,
	sizeof(struct rtc_time)))
	return -EFAULT;

	set_time(&time);
	break;
	case RTC_IRQP_READ:
	return put_user(periodic_frequency, (unsigned long __user *)arg);
	break;
	case RTC_IRQP_SET:
	if (arg > MAX_PERIODIC_RATE)
	return -EINVAL;

	if (from == FUNCTION_RTC_IOCTL && arg > MAX_USER_PERIODIC_RATE &&
	capable(CAP_SYS_RESOURCE) == 0)
	return -EACCES;

	periodic_frequency = arg;

	count = RTC_FREQUENCY;
	do_div(count, arg);

	periodic_count = count;

	spin_lock_irq(&rtc_lock);

	rtc1_write(RTCL1LREG, count);
	rtc1_write(RTCL1HREG, count >> 16);

	spin_unlock_irq(&rtc_lock);
	break;
	case RTC_EPOCH_READ:
	return put_user(epoch, (unsigned long __user *)arg);
	case RTC_EPOCH_SET:
	/* Doesn't support before 1900 */
	if (arg < 1900)
	return -EINVAL;

	if (capable(CAP_SYS_TIME) == 0)
	return -EACCES;

	epoch = arg;
	break;
	default:
	return -EINVAL;
	}

	return 0;
	}

	static int rtc_ioctl(struct inode inode, struct file file, unsigned int cmd,
	unsigned long arg)
	{
	return rtc_do_ioctl(cmd, arg, FUNCTION_RTC_IOCTL);
	}

	static int rtc_open(struct inode inode, struct file file)
	{
	spin_lock_irq(&rtc_lock);

	if (rtc_status == RTC_OPEN) {
	spin_unlock_irq(&rtc_lock);
	return -EBUSY;
	}

	rtc_status = RTC_OPEN;
	rtc_irq_data = 0;

	spin_unlock_irq(&rtc_lock);

	return 0;
	}

	static int rtc_release(struct inode inode, struct file file)
	{
	if (file->f_flags & FASYNC)
	(void)fasync_helper(-1, file, 0, &rtc_async_queue);

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;

	spin_unlock_irq(&rtc_lock);

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	return 0;
	}

	static int rtc_fasync(int fd, struct file *file, int on)
	{
	return fasync_helper(fd, file, on, &rtc_async_queue);
	}

	static struct file_operations rtc_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.read = rtc_read,
	.poll = rtc_poll,
	.ioctl = rtc_ioctl,
	.open = rtc_open,
	.release = rtc_release,
	.fasync = rtc_fasync,
	};

	static irqreturn_t elapsedtime_interrupt(int irq, void dev_id, struct pt_regs regs)
	{
	spin_lock(&rtc_lock);
	rtc2_write(RTCINTREG, ELAPSEDTIME_INT);

	rtc_irq_data += 0x100;
	rtc_irq_data &= ~0xff;
	rtc_irq_data \|= RTC_AF;
	spin_unlock(&rtc_lock);

	spin_lock(&rtc_lock);
	if (rtc_callback)
	rtc_callback->func(rtc_callback->private_data);
	spin_unlock(&rtc_lock);

	wake_up_interruptible(&rtc_wait);

	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

	return IRQ_HANDLED;
	}

	static irqreturn_t rtclong1_interrupt(int irq, void dev_id, struct pt_regs regs)
	{
	unsigned long count = periodic_count;

	spin_lock(&rtc_lock);
	rtc2_write(RTCINTREG, RTCLONG1_INT);

	rtc1_write(RTCL1LREG, count);
	rtc1_write(RTCL1HREG, count >> 16);

	rtc_irq_data += 0x100;
	rtc_irq_data &= ~0xff;
	rtc_irq_data \|= RTC_PF;
	spin_unlock(&rtc_lock);

	spin_lock(&rtc_task_lock);
	if (rtc_callback)
	rtc_callback->func(rtc_callback->private_data);
	spin_unlock(&rtc_task_lock);

	wake_up_interruptible(&rtc_wait);

	kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);

	return IRQ_HANDLED;
	}

	int rtc_register(rtc_task_t *task)
	{
	if (task == NULL \|\| task->func == NULL)
	return -EINVAL;

	spin_lock_irq(&rtc_lock);
	if (rtc_status == RTC_OPEN) {
	spin_unlock_irq(&rtc_lock);
	return -EBUSY;
	}

	spin_lock(&rtc_task_lock);
	if (rtc_callback != NULL) {
	spin_unlock(&rtc_task_lock);
	spin_unlock_irq(&rtc_task_lock);
	return -EBUSY;
	}

	rtc_callback = task;
	spin_unlock(&rtc_task_lock);

	rtc_status = RTC_OPEN;

	spin_unlock_irq(&rtc_lock);

	return 0;
	}

	EXPORT_SYMBOL_GPL(rtc_register);

	int rtc_unregister(rtc_task_t *task)
	{
	spin_lock_irq(&rtc_task_lock);
	if (task == NULL \|\| rtc_callback != task) {
	spin_unlock_irq(&rtc_task_lock);
	return -ENXIO;
	}

	spin_lock(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;

	spin_unlock(&rtc_lock);

	rtc_callback = NULL;

	spin_unlock_irq(&rtc_task_lock);

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	return 0;
	}

	EXPORT_SYMBOL_GPL(rtc_unregister);

	int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
	{
	int retval = 0;

	spin_lock_irq(&rtc_task_lock);

	if (rtc_callback != task)
	retval = -ENXIO;
	else
	rtc_do_ioctl(cmd, arg, FUNCTION_RTC_CONTROL);

	spin_unlock_irq(&rtc_task_lock);

	return retval;
	}

	EXPORT_SYMBOL_GPL(rtc_control);

	static struct miscdevice rtc_miscdevice = {
	.minor = RTC_MINOR,
	.name = rtc_name,
	.fops = &rtc_fops,
	};

	static int rtc_probe(struct device *dev)
	{
	struct platform_device *pdev;
	unsigned int irq;
	int retval;

	pdev = to_platform_device(dev);
	if (pdev->num_resources != 2)
	return -EBUSY;

	rtc1_base = ioremap(pdev->resource[0].start, RTC1_SIZE);
	if (rtc1_base == NULL)
	return -EBUSY;

	rtc2_base = ioremap(pdev->resource[1].start, RTC2_SIZE);
	if (rtc2_base == NULL) {
	iounmap(rtc1_base);
	rtc1_base = NULL;
	return -EBUSY;
	}

	retval = misc_register(&rtc_miscdevice);
	if (retval < 0) {
	iounmap(rtc1_base);
	iounmap(rtc2_base);
	rtc1_base = NULL;
	rtc2_base = NULL;
	return retval;
	}

	spin_lock_irq(&rtc_lock);

	rtc1_write(ECMPLREG, 0);
	rtc1_write(ECMPMREG, 0);
	rtc1_write(ECMPHREG, 0);
	rtc1_write(RTCL1LREG, 0);
	rtc1_write(RTCL1HREG, 0);

	rtc_status = RTC_RELEASE;
	rtc_irq_data = 0;

	spin_unlock_irq(&rtc_lock);

	init_waitqueue_head(&rtc_wait);

	irq = ELAPSEDTIME_IRQ;
	retval = request_irq(irq, elapsedtime_interrupt, SA_INTERRUPT,
	"elapsed_time", NULL);
	if (retval == 0) {
	irq = RTCLONG1_IRQ;
	retval = request_irq(irq, rtclong1_interrupt, SA_INTERRUPT,
	"rtclong1", NULL);
	}

	if (retval < 0) {
	printk(KERN_ERR "rtc: IRQ%d is busy\n", irq);
	if (irq == RTCLONG1_IRQ)
	free_irq(ELAPSEDTIME_IRQ, NULL);
	iounmap(rtc1_base);
	iounmap(rtc2_base);
	rtc1_base = NULL;
	rtc2_base = NULL;
	return retval;
	}

	disable_irq(ELAPSEDTIME_IRQ);
	disable_irq(RTCLONG1_IRQ);

	spin_lock_init(&rtc_task_lock);

	printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");

	return 0;
	}

	static int rtc_remove(struct device *dev)
	{
	int retval;

	retval = misc_deregister(&rtc_miscdevice);
	if (retval < 0)
	return retval;

	free_irq(ELAPSEDTIME_IRQ, NULL);
	free_irq(RTCLONG1_IRQ, NULL);
	if (rtc1_base != NULL)
	iounmap(rtc1_base);
	if (rtc2_base != NULL)
	iounmap(rtc2_base);

	return 0;
	}

	static struct platform_device *rtc_platform_device;

	static struct device_driver rtc_device_driver = {
	.name = rtc_name,
	.bus = &platform_bus_type,
	.probe = rtc_probe,
	.remove = rtc_remove,
	};

	static int __devinit vr41xx_rtc_init(void)
	{
	int retval;

	switch (current_cpu_data.cputype) {
	case CPU_VR4111:
	case CPU_VR4121:
	rtc_resource[0].start = RTC1_TYPE1_START;
	rtc_resource[0].end = RTC1_TYPE1_END;
	rtc_resource[1].start = RTC2_TYPE1_START;
	rtc_resource[1].end = RTC2_TYPE1_END;
	break;
	case CPU_VR4122:
	case CPU_VR4131:
	case CPU_VR4133:
	rtc_resource[0].start = RTC1_TYPE2_START;
	rtc_resource[0].end = RTC1_TYPE2_END;
	rtc_resource[1].start = RTC2_TYPE2_START;
	rtc_resource[1].end = RTC2_TYPE2_END;
	break;
	default:
	return -ENODEV;
	break;
	}

	rtc_platform_device = platform_device_register_simple("RTC", -1, rtc_resource, RTC_NUM_RESOURCES);
	if (IS_ERR(rtc_platform_device))
	return PTR_ERR(rtc_platform_device);

	retval = driver_register(&rtc_device_driver);
	if (retval < 0)
	platform_device_unregister(rtc_platform_device);

	return retval;
	}

	static void __devexit vr41xx_rtc_exit(void)
	{
	driver_unregister(&rtc_device_driver);

	platform_device_unregister(rtc_platform_device);
	}

	module_init(vr41xx_rtc_init);
	module_exit(vr41xx_rtc_exit);