arch/cris/arch-v10/drivers/pcf8563.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * PCF8563 RTC
  *
  * From Phillips' datasheet:
  *
  * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
  * consumption. A programmable clock output, interrupt output and voltage
  * low detector are also provided. All address and data are transferred
  * serially via two-line bidirectional I2C-bus. Maximum bus speed is
  * 400 kbits/s. The built-in word address register is incremented
  * automatically after each written or read byte.
  *
  * Copyright (c) 2002-2007, Axis Communications AB
  * All rights reserved.
  *
  * Author: Tobias Anderberg <tobiasa@axis.com>.
  *
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/ioctl.h>
 #include <linux/delay.h>
 #include <linux/bcd.h>
 #include <linux/mutex.h>

 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <asm/io.h>
 #include <asm/rtc.h>

 #include "i2c.h"

 #define PCF8563_MAJOR 121	/* Local major number. */
 #define DEVICE_NAME "rtc"	/* Name which is registered in /proc/devices. */
 #define PCF8563_NAME "PCF8563"
 #define DRIVER_VERSION "$Revision: 1.24 $"

 /* I2C bus slave registers. */
 #define RTC_I2C_READ		0xa3
 #define RTC_I2C_WRITE		0xa2

 /* Two simple wrapper macros, saves a few keystrokes. */
 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)

 static DEFINE_MUTEX(pcf8563_mutex);
 static DEFINE_MUTEX(rtc_lock); /* Protect state etc */

 static const unsigned char days_in_month[] =
 	{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

 static long pcf8563_unlocked_ioctl(struct file *, unsigned int, unsigned long);

 /* Cache VL bit value read at driver init since writing the RTC_SECOND
  * register clears the VL status.
  */
 static int voltage_low;

 static const struct file_operations pcf8563_fops = {
 	.owner = THIS_MODULE,
 	.unlocked_ioctl = pcf8563_unlocked_ioctl,
 	.llseek		= noop_llseek,
 };

 unsigned char
 pcf8563_readreg(int reg)
 {
 	unsigned char res = rtc_read(reg);

 	/* The PCF8563 does not return 0 for unimplemented bits. */
 	switch (reg) {
 	case RTC_SECONDS:
 	case RTC_MINUTES:
 		res &= 0x7F;
 		break;
 	case RTC_HOURS:
 	case RTC_DAY_OF_MONTH:
 		res &= 0x3F;
 		break;
 	case RTC_WEEKDAY:
 		res &= 0x07;
 		break;
 	case RTC_MONTH:
 		res &= 0x1F;
 		break;
 	case RTC_CONTROL1:
 		res &= 0xA8;
 		break;
 	case RTC_CONTROL2:
 		res &= 0x1F;
 		break;
 	case RTC_CLOCKOUT_FREQ:
 	case RTC_TIMER_CONTROL:
 		res &= 0x83;
 		break;
 	}
 	return res;
 }

 void
 pcf8563_writereg(int reg, unsigned char val)
 {
 	rtc_write(reg, val);
 }

 void
 get_rtc_time(struct rtc_time *tm)
 {
 	tm->tm_sec  = rtc_read(RTC_SECONDS);
 	tm->tm_min  = rtc_read(RTC_MINUTES);
 	tm->tm_hour = rtc_read(RTC_HOURS);
 	tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 	tm->tm_wday = rtc_read(RTC_WEEKDAY);
 	tm->tm_mon  = rtc_read(RTC_MONTH);
 	tm->tm_year = rtc_read(RTC_YEAR);

 	if (tm->tm_sec & 0x80) {
 		printk(KERN_ERR "%s: RTC Voltage Low - reliable date/time "
 		       "information is no longer guaranteed!\n", PCF8563_NAME);
 	}

 	tm->tm_year  = bcd2bin(tm->tm_year) +
 		       ((tm->tm_mon & 0x80) ? 100 : 0);
 	tm->tm_sec  &= 0x7F;
 	tm->tm_min  &= 0x7F;
 	tm->tm_hour &= 0x3F;
 	tm->tm_mday &= 0x3F;
 	tm->tm_wday &= 0x07; /* Not coded in BCD. */
 	tm->tm_mon  &= 0x1F;

 	tm->tm_sec = bcd2bin(tm->tm_sec);
 	tm->tm_min = bcd2bin(tm->tm_min);
 	tm->tm_hour = bcd2bin(tm->tm_hour);
 	tm->tm_mday = bcd2bin(tm->tm_mday);
 	tm->tm_mon = bcd2bin(tm->tm_mon);
 	tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 }

 int __init
 pcf8563_init(void)
 {
 	static int res;
 	static int first = 1;

 	if (!first)
 		return res;
 	first = 0;

 	/* Initiate the i2c protocol. */
 	res = i2c_init();
 	if (res < 0) {
 		printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
 		return res;
 	}

 	/*
 	 * First of all we need to reset the chip. This is done by
 	 * clearing control1, control2 and clk freq and resetting
 	 * all alarms.
 	 */
 	if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 		goto err;

 	if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 		goto err;

 	if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 		goto err;

 	if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 		goto err;

 	/* Reset the alarms. */
 	if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 		goto err;

 	if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 		goto err;

 	if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 		goto err;

 	if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 		goto err;

 	/* Check for low voltage, and warn about it. */
 	if (rtc_read(RTC_SECONDS) & 0x80) {
 		voltage_low = 1;
 		printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 		       "date/time information is no longer guaranteed!\n",
 		       PCF8563_NAME);
 	}

 	return res;

 err:
 	printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 	res = -1;
 	return res;
 }

 void __exit
 pcf8563_exit(void)
 {
 	unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
 }

 /*
  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
  * POSIX says so!
  */
 static int pcf8563_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	/* Some sanity checks. */
 	if (_IOC_TYPE(cmd) != RTC_MAGIC)
 		return -ENOTTY;

 	if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 		return -ENOTTY;

 	switch (cmd) {
 	case RTC_RD_TIME:
 	{
 		struct rtc_time tm;

 		mutex_lock(&rtc_lock);
 		memset(&tm, 0, sizeof tm);
 		get_rtc_time(&tm);

 		if (copy_to_user((struct rtc_time *) arg, &tm,
 				 sizeof tm)) {
 			mutex_unlock(&rtc_lock);
 			return -EFAULT;
 		}

 		mutex_unlock(&rtc_lock);

 		return 0;
 	}
 	case RTC_SET_TIME:
 	{
 		int leap;
 		int year;
 		int century;
 		struct rtc_time tm;

 		memset(&tm, 0, sizeof tm);
 		if (!capable(CAP_SYS_TIME))
 			return -EPERM;

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

 		/* Convert from struct tm to struct rtc_time. */
 		tm.tm_year += 1900;
 		tm.tm_mon += 1;

 		/*
 		 * Check if tm.tm_year is a leap year. A year is a leap
 		 * year if it is divisible by 4 but not 100, except
 		 * that years divisible by 400 _are_ leap years.
 		 */
 		year = tm.tm_year;
 		leap = (tm.tm_mon == 2) &&
 			((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);

 		/* Perform some sanity checks. */
 		if ((tm.tm_year < 1970) ||
 		    (tm.tm_mon > 12) ||
 		    (tm.tm_mday == 0) ||
 		    (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 		    (tm.tm_wday >= 7) ||
 		    (tm.tm_hour >= 24) ||
 		    (tm.tm_min >= 60) ||
 		    (tm.tm_sec >= 60))
 			return -EINVAL;

 		century = (tm.tm_year >= 2000) ? 0x80 : 0;
 		tm.tm_year = tm.tm_year % 100;

 		tm.tm_year = bin2bcd(tm.tm_year);
 		tm.tm_mon = bin2bcd(tm.tm_mon);
 		tm.tm_mday = bin2bcd(tm.tm_mday);
 		tm.tm_hour = bin2bcd(tm.tm_hour);
 		tm.tm_min = bin2bcd(tm.tm_min);
 		tm.tm_sec = bin2bcd(tm.tm_sec);
 		tm.tm_mon |= century;

 		mutex_lock(&rtc_lock);

 		rtc_write(RTC_YEAR, tm.tm_year);
 		rtc_write(RTC_MONTH, tm.tm_mon);
 		rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
 		rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 		rtc_write(RTC_HOURS, tm.tm_hour);
 		rtc_write(RTC_MINUTES, tm.tm_min);
 		rtc_write(RTC_SECONDS, tm.tm_sec);

 		mutex_unlock(&rtc_lock);

 		return 0;
 	}
 	case RTC_VL_READ:
 		if (voltage_low) {
 			printk(KERN_ERR "%s: RTC Voltage Low - "
 			       "reliable date/time information is no "
 			       "longer guaranteed!\n", PCF8563_NAME);
 		}

 		if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
 			return -EFAULT;
 		return 0;

 	case RTC_VL_CLR:
 	{
 		/* Clear the VL bit in the seconds register in case
 		 * the time has not been set already (which would
 		 * have cleared it). This does not really matter
 		 * because of the cached voltage_low value but do it
 		 * anyway for consistency. */

 		int ret = rtc_read(RTC_SECONDS);

 		rtc_write(RTC_SECONDS, (ret & 0x7F));

 		/* Clear the cached value. */
 		voltage_low = 0;

 		return 0;
 	}
 	default:
 		return -ENOTTY;
 	}

 	return 0;
 }

 static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	int ret;

 	mutex_lock(&pcf8563_mutex);
 	ret = pcf8563_ioctl(filp, cmd, arg);
 	mutex_unlock(&pcf8563_mutex);

 	return ret;
 }

 static int __init pcf8563_register(void)
 {
 	if (pcf8563_init() < 0) {
 		printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
 		       "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 		return -1;
 	}

 	if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 		printk(KERN_INFO "%s: Unable to get major number %d for RTC device.\n",
 		       PCF8563_NAME, PCF8563_MAJOR);
 		return -1;
 	}

 	printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
 	       DRIVER_VERSION);

 	/* Check for low voltage, and warn about it. */
 	if (voltage_low) {
 		printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 		       "information is no longer guaranteed!\n", PCF8563_NAME);
 	}

 	return 0;
 }

 module_init(pcf8563_register);
 module_exit(pcf8563_exit);
	/*
	* PCF8563 RTC
	*
	* From Phillips' datasheet:
	*
	* The PCF8563 is a CMOS real-time clock/calendar optimized for low power
	* consumption. A programmable clock output, interrupt output and voltage
	* low detector are also provided. All address and data are transferred
	* serially via two-line bidirectional I2C-bus. Maximum bus speed is
	* 400 kbits/s. The built-in word address register is incremented
	* automatically after each written or read byte.
	*
	* Copyright (c) 2002-2007, Axis Communications AB
	* All rights reserved.
	*
	* Author: Tobias Anderberg <tobiasa@axis.com>.
	*
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/sched.h>
	#include <linux/init.h>
	#include <linux/fs.h>
	#include <linux/ioctl.h>
	#include <linux/delay.h>
	#include <linux/bcd.h>
	#include <linux/mutex.h>

	#include <asm/uaccess.h>
	#include <asm/system.h>
	#include <asm/io.h>
	#include <asm/rtc.h>

	#include "i2c.h"

	#define PCF8563_MAJOR 121 /* Local major number. */
	#define DEVICE_NAME "rtc" /* Name which is registered in /proc/devices. */
	#define PCF8563_NAME "PCF8563"
	#define DRIVER_VERSION "$Revision: 1.24 $"

	/* I2C bus slave registers. */
	#define RTC_I2C_READ 0xa3
	#define RTC_I2C_WRITE 0xa2

	/* Two simple wrapper macros, saves a few keystrokes. */
	#define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
	#define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)

	static DEFINE_MUTEX(pcf8563_mutex);
	static DEFINE_MUTEX(rtc_lock); /* Protect state etc */

	static const unsigned char days_in_month[] =
	{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

	static long pcf8563_unlocked_ioctl(struct file *, unsigned int, unsigned long);

	/* Cache VL bit value read at driver init since writing the RTC_SECOND
	* register clears the VL status.
	*/
	static int voltage_low;

	static const struct file_operations pcf8563_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = pcf8563_unlocked_ioctl,
	.llseek = noop_llseek,
	};

	unsigned char
	pcf8563_readreg(int reg)
	{
	unsigned char res = rtc_read(reg);

	/* The PCF8563 does not return 0 for unimplemented bits. */
	switch (reg) {
	case RTC_SECONDS:
	case RTC_MINUTES:
	res &= 0x7F;
	break;
	case RTC_HOURS:
	case RTC_DAY_OF_MONTH:
	res &= 0x3F;
	break;
	case RTC_WEEKDAY:
	res &= 0x07;
	break;
	case RTC_MONTH:
	res &= 0x1F;
	break;
	case RTC_CONTROL1:
	res &= 0xA8;
	break;
	case RTC_CONTROL2:
	res &= 0x1F;
	break;
	case RTC_CLOCKOUT_FREQ:
	case RTC_TIMER_CONTROL:
	res &= 0x83;
	break;
	}
	return res;
	}

	void
	pcf8563_writereg(int reg, unsigned char val)
	{
	rtc_write(reg, val);
	}

	void
	get_rtc_time(struct rtc_time *tm)
	{
	tm->tm_sec = rtc_read(RTC_SECONDS);
	tm->tm_min = rtc_read(RTC_MINUTES);
	tm->tm_hour = rtc_read(RTC_HOURS);
	tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
	tm->tm_wday = rtc_read(RTC_WEEKDAY);
	tm->tm_mon = rtc_read(RTC_MONTH);
	tm->tm_year = rtc_read(RTC_YEAR);

	if (tm->tm_sec & 0x80) {
	printk(KERN_ERR "%s: RTC Voltage Low - reliable date/time "
	"information is no longer guaranteed!\n", PCF8563_NAME);
	}

	tm->tm_year = bcd2bin(tm->tm_year) +
	((tm->tm_mon & 0x80) ? 100 : 0);
	tm->tm_sec &= 0x7F;
	tm->tm_min &= 0x7F;
	tm->tm_hour &= 0x3F;
	tm->tm_mday &= 0x3F;
	tm->tm_wday &= 0x07; /* Not coded in BCD. */
	tm->tm_mon &= 0x1F;

	tm->tm_sec = bcd2bin(tm->tm_sec);
	tm->tm_min = bcd2bin(tm->tm_min);
	tm->tm_hour = bcd2bin(tm->tm_hour);
	tm->tm_mday = bcd2bin(tm->tm_mday);
	tm->tm_mon = bcd2bin(tm->tm_mon);
	tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
	}

	int __init
	pcf8563_init(void)
	{
	static int res;
	static int first = 1;

	if (!first)
	return res;
	first = 0;

	/* Initiate the i2c protocol. */
	res = i2c_init();
	if (res < 0) {
	printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
	return res;
	}

	/*
	* First of all we need to reset the chip. This is done by
	* clearing control1, control2 and clk freq and resetting
	* all alarms.
	*/
	if (rtc_write(RTC_CONTROL1, 0x00) < 0)
	goto err;

	if (rtc_write(RTC_CONTROL2, 0x00) < 0)
	goto err;

	if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
	goto err;

	if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
	goto err;

	/* Reset the alarms. */
	if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
	goto err;

	if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
	goto err;

	if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
	goto err;

	if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
	goto err;

	/* Check for low voltage, and warn about it. */
	if (rtc_read(RTC_SECONDS) & 0x80) {
	voltage_low = 1;
	printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
	"date/time information is no longer guaranteed!\n",
	PCF8563_NAME);
	}

	return res;

	err:
	printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
	res = -1;
	return res;
	}

	void __exit
	pcf8563_exit(void)
	{
	unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
	}

	/*
	* ioctl calls for this driver. Why return -ENOTTY upon error? Because
	* POSIX says so!
	*/
	static int pcf8563_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	{
	/* Some sanity checks. */
	if (_IOC_TYPE(cmd) != RTC_MAGIC)
	return -ENOTTY;

	if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
	return -ENOTTY;

	switch (cmd) {
	case RTC_RD_TIME:
	{
	struct rtc_time tm;

	mutex_lock(&rtc_lock);
	memset(&tm, 0, sizeof tm);
	get_rtc_time(&tm);

	if (copy_to_user((struct rtc_time *) arg, &tm,
	sizeof tm)) {
	mutex_unlock(&rtc_lock);
	return -EFAULT;
	}

	mutex_unlock(&rtc_lock);

	return 0;
	}
	case RTC_SET_TIME:
	{
	int leap;
	int year;
	int century;
	struct rtc_time tm;

	memset(&tm, 0, sizeof tm);
	if (!capable(CAP_SYS_TIME))
	return -EPERM;

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

	/* Convert from struct tm to struct rtc_time. */
	tm.tm_year += 1900;
	tm.tm_mon += 1;

	/*
	* Check if tm.tm_year is a leap year. A year is a leap
	* year if it is divisible by 4 but not 100, except
	* that years divisible by 400 _are_ leap years.
	*/
	year = tm.tm_year;
	leap = (tm.tm_mon == 2) &&
	((year % 4 == 0 && year % 100 != 0) \|\| year % 400 == 0);

	/* Perform some sanity checks. */
	if ((tm.tm_year < 1970) \|\|
	(tm.tm_mon > 12) \|\|
	(tm.tm_mday == 0) \|\|
	(tm.tm_mday > days_in_month[tm.tm_mon] + leap) \|\|
	(tm.tm_wday >= 7) \|\|
	(tm.tm_hour >= 24) \|\|
	(tm.tm_min >= 60) \|\|
	(tm.tm_sec >= 60))
	return -EINVAL;

	century = (tm.tm_year >= 2000) ? 0x80 : 0;
	tm.tm_year = tm.tm_year % 100;

	tm.tm_year = bin2bcd(tm.tm_year);
	tm.tm_mon = bin2bcd(tm.tm_mon);
	tm.tm_mday = bin2bcd(tm.tm_mday);
	tm.tm_hour = bin2bcd(tm.tm_hour);
	tm.tm_min = bin2bcd(tm.tm_min);
	tm.tm_sec = bin2bcd(tm.tm_sec);
	tm.tm_mon \|= century;

	mutex_lock(&rtc_lock);

	rtc_write(RTC_YEAR, tm.tm_year);
	rtc_write(RTC_MONTH, tm.tm_mon);
	rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
	rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
	rtc_write(RTC_HOURS, tm.tm_hour);
	rtc_write(RTC_MINUTES, tm.tm_min);
	rtc_write(RTC_SECONDS, tm.tm_sec);

	mutex_unlock(&rtc_lock);

	return 0;
	}
	case RTC_VL_READ:
	if (voltage_low) {
	printk(KERN_ERR "%s: RTC Voltage Low - "
	"reliable date/time information is no "
	"longer guaranteed!\n", PCF8563_NAME);
	}

	if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
	return -EFAULT;
	return 0;

	case RTC_VL_CLR:
	{
	/* Clear the VL bit in the seconds register in case
	* the time has not been set already (which would
	* have cleared it). This does not really matter
	* because of the cached voltage_low value but do it
	* anyway for consistency. */

	int ret = rtc_read(RTC_SECONDS);

	rtc_write(RTC_SECONDS, (ret & 0x7F));

	/* Clear the cached value. */
	voltage_low = 0;

	return 0;
	}
	default:
	return -ENOTTY;
	}

	return 0;
	}

	static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
	{
	int ret;

	mutex_lock(&pcf8563_mutex);
	ret = pcf8563_ioctl(filp, cmd, arg);
	mutex_unlock(&pcf8563_mutex);

	return ret;
	}

	static int __init pcf8563_register(void)
	{
	if (pcf8563_init() < 0) {
	printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
	"Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
	return -1;
	}

	if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
	printk(KERN_INFO "%s: Unable to get major number %d for RTC device.\n",
	PCF8563_NAME, PCF8563_MAJOR);
	return -1;
	}

	printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
	DRIVER_VERSION);

	/* Check for low voltage, and warn about it. */
	if (voltage_low) {
	printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
	"information is no longer guaranteed!\n", PCF8563_NAME);
	}

	return 0;
	}

	module_init(pcf8563_register);
	module_exit(pcf8563_exit);