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Commit caaff562 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Linus Torvalds
Browse files

rtc: add rtc-m41t80 driver 



This is a new-style i2c driver for ST M41T80 series RTC chip, derived from
works by Alexander Bigga <ab@mycable.de> who wrote the original
rtc-m41txx.c based on drivers/i2c/chips/m41t00.c driver.

This driver supports M41T8[0-4] and M41ST8[457].  The old m41t00 driver
supports M41T00, M41T81 and M41T85(M41ST85).  While the M41T00 chip is now
supported by rtc-ds1307 driver, this driver does not include support for
the chip.

[akpm@linux-foundation.org: remove bogus `static']
Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarAlexander Bigga <ab@mycable.de>
Acked-by: default avatarMark A. Greer <mgreer@mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5663c14b

drivers/rtc/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -212,6 +212,18 @@ config RTC_DRV_PCF8583 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-pcf8583.



config RTC_DRV_M41T80

	tristate "ST M41T80 series RTC"

	depends on RTC_CLASS && I2C

	help

	  If you say Y here you will get support for the

	  ST M41T80 RTC chips series. Currently following chips are

	  supported: M41T80, M41T81, M41T82, M41T83, M41ST84, M41ST85

	  and M41ST87.



	  This driver can also be built as a module. If so, the module

	  will be called rtc-m41t80.



comment "SPI RTC drivers"

	depends on RTC_CLASS && SPI_MASTER

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_RTC_DRV_PCF8583) += rtc-pcf8583.o 
obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o

obj-$(CONFIG_RTC_DRV_S3C)	+= rtc-s3c.o

obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o

obj-$(CONFIG_RTC_DRV_M41T80)	+= rtc-m41t80.o

obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o

obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o

obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o

drivers/rtc/rtc-m41t80.c

0 → 100644
+629 −0
Original line number Diff line number Diff line 
/*

 * I2C client/driver for the ST M41T80 family of i2c rtc chips.

 *

 * Author: Alexander Bigga <ab@mycable.de>

 *

 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>

 *

 * 2006 (c) mycable GmbH

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/i2c.h>

#include <linux/rtc.h>

#include <linux/bcd.h>



#define M41T80_REG_SSEC	0

#define M41T80_REG_SEC	1

#define M41T80_REG_MIN	2

#define M41T80_REG_HOUR	3

#define M41T80_REG_WDAY	4

#define M41T80_REG_DAY	5

#define M41T80_REG_MON	6

#define M41T80_REG_YEAR	7

#define M41T80_REG_ALARM_MON	0xa

#define M41T80_REG_ALARM_DAY	0xb

#define M41T80_REG_ALARM_HOUR	0xc

#define M41T80_REG_ALARM_MIN	0xd

#define M41T80_REG_ALARM_SEC	0xe

#define M41T80_REG_FLAGS	0xf

#define M41T80_REG_SQW	0x13



#define M41T80_DATETIME_REG_SIZE	(M41T80_REG_YEAR + 1)

#define M41T80_ALARM_REG_SIZE	\

	(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)



#define M41T80_SEC_ST		(1 << 7)	/* ST: Stop Bit */

#define M41T80_ALMON_AFE	(1 << 7)	/* AFE: AF Enable Bit */

#define M41T80_ALMON_SQWE	(1 << 6)	/* SQWE: SQW Enable Bit */

#define M41T80_ALHOUR_HT	(1 << 6)	/* HT: Halt Update Bit */

#define M41T80_FLAGS_AF		(1 << 6)	/* AF: Alarm Flag Bit */

#define M41T80_FLAGS_BATT_LOW	(1 << 4)	/* BL: Battery Low Bit */



#define M41T80_FEATURE_HT	(1 << 0)

#define M41T80_FEATURE_BL	(1 << 1)



#define DRV_VERSION "0.05"



struct m41t80_chip_info {

	const char *name;

	u8 features;

};



static const struct m41t80_chip_info m41t80_chip_info_tbl[] = {

	{

		.name		= "m41t80",

		.features	= 0,

	},

	{

		.name		= "m41t81",

		.features	= M41T80_FEATURE_HT,

	},

	{

		.name		= "m41t81s",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

	{

		.name		= "m41t82",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

	{

		.name		= "m41t83",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

	{

		.name		= "m41st84",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

	{

		.name		= "m41st85",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

	{

		.name		= "m41st87",

		.features	= M41T80_FEATURE_HT | M41T80_FEATURE_BL,

	},

};



struct m41t80_data {

	const struct m41t80_chip_info *chip;

	struct rtc_device *rtc;

};



static int m41t80_get_datetime(struct i2c_client *client,

			       struct rtc_time *tm)

{

	u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1,

			.buf	= dt_addr,

		},

		{

			.addr	= client->addr,

			.flags	= I2C_M_RD,

			.len	= M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,

			.buf	= buf + M41T80_REG_SEC,

		},

	};



	if (i2c_transfer(client->adapter, msgs, 2) < 0) {

		dev_err(&client->dev, "read error\n");

		return -EIO;

	}



	tm->tm_sec = BCD2BIN(buf[M41T80_REG_SEC] & 0x7f);

	tm->tm_min = BCD2BIN(buf[M41T80_REG_MIN] & 0x7f);

	tm->tm_hour = BCD2BIN(buf[M41T80_REG_HOUR] & 0x3f);

	tm->tm_mday = BCD2BIN(buf[M41T80_REG_DAY] & 0x3f);

	tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;

	tm->tm_mon = BCD2BIN(buf[M41T80_REG_MON] & 0x1f) - 1;



	/* assume 20YY not 19YY, and ignore the Century Bit */

	tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]) + 100;

	return 0;

}



/* Sets the given date and time to the real time clock. */

static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];

	u8 *buf = &wbuf[1];

	u8 dt_addr[1] = { M41T80_REG_SEC };

	struct i2c_msg msgs_in[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1,

			.buf	= dt_addr,

		},

		{

			.addr	= client->addr,

			.flags	= I2C_M_RD,

			.len	= M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,

			.buf	= buf + M41T80_REG_SEC,

		},

	};

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1 + M41T80_DATETIME_REG_SIZE,

			.buf	= wbuf,

		 },

	};



	/* Read current reg values into buf[1..7] */

	if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {

		dev_err(&client->dev, "read error\n");

		return -EIO;

	}



	wbuf[0] = 0; /* offset into rtc's regs */

	/* Merge time-data and register flags into buf[0..7] */

	buf[M41T80_REG_SSEC] = 0;

	buf[M41T80_REG_SEC] =

		BIN2BCD(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);

	buf[M41T80_REG_MIN] =

		BIN2BCD(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);

	buf[M41T80_REG_HOUR] =

		BIN2BCD(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;

	buf[M41T80_REG_WDAY] =

		(tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);

	buf[M41T80_REG_DAY] =

		BIN2BCD(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);

	buf[M41T80_REG_MON] =

		BIN2BCD(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);

	/* assume 20YY not 19YY */

	buf[M41T80_REG_YEAR] = BIN2BCD(tm->tm_year % 100);



	if (i2c_transfer(client->adapter, msgs, 1) != 1) {

		dev_err(&client->dev, "write error\n");

		return -EIO;

	}

	return 0;

}



#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)

static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)

{

	struct i2c_client *client = to_i2c_client(dev);

	struct m41t80_data *clientdata = i2c_get_clientdata(client);

	u8 reg;



	if (clientdata->chip->features & M41T80_FEATURE_BL) {

		reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);

		seq_printf(seq, "battery\t\t: %s\n",

			   (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");

	}

	return 0;

}

#else

#define m41t80_rtc_proc NULL

#endif



static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	return m41t80_get_datetime(to_i2c_client(dev), tm);

}



static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	return m41t80_set_datetime(to_i2c_client(dev), tm);

}



#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)

static int

m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)

{

	struct i2c_client *client = to_i2c_client(dev);

	int rc;



	switch (cmd) {

	case RTC_AIE_OFF:

	case RTC_AIE_ON:

		break;

	default:

		return -ENOIOCTLCMD;

	}



	rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);

	if (rc < 0)

		goto err;

	switch (cmd) {

	case RTC_AIE_OFF:

		rc &= ~M41T80_ALMON_AFE;

		break;

	case RTC_AIE_ON:

		rc |= M41T80_ALMON_AFE;

		break;

	}

	if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)

		goto err;

	return 0;

err:

	return -EIO;

}

#else

#define	m41t80_rtc_ioctl NULL

#endif



static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)

{

	struct i2c_client *client = to_i2c_client(dev);

	u8 wbuf[1 + M41T80_ALARM_REG_SIZE];

	u8 *buf = &wbuf[1];

	u8 *reg = buf - M41T80_REG_ALARM_MON;

	u8 dt_addr[1] = { M41T80_REG_ALARM_MON };

	struct i2c_msg msgs_in[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1,

			.buf	= dt_addr,

		},

		{

			.addr	= client->addr,

			.flags	= I2C_M_RD,

			.len	= M41T80_ALARM_REG_SIZE,

			.buf	= buf,

		},

	};

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1 + M41T80_ALARM_REG_SIZE,

			.buf	= wbuf,

		 },

	};



	if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {

		dev_err(&client->dev, "read error\n");

		return -EIO;

	}

	reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);

	reg[M41T80_REG_ALARM_DAY] = 0;

	reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);

	reg[M41T80_REG_ALARM_MIN] = 0;

	reg[M41T80_REG_ALARM_SEC] = 0;



	wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */

	reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?

		BIN2BCD(t->time.tm_sec) : 0x80;

	reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?

		BIN2BCD(t->time.tm_min) : 0x80;

	reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?

		BIN2BCD(t->time.tm_hour) : 0x80;

	reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?

		BIN2BCD(t->time.tm_mday) : 0x80;

	if (t->time.tm_mon >= 0)

		reg[M41T80_REG_ALARM_MON] |= BIN2BCD(t->time.tm_mon + 1);

	else

		reg[M41T80_REG_ALARM_DAY] |= 0x40;



	if (i2c_transfer(client->adapter, msgs, 1) != 1) {

		dev_err(&client->dev, "write error\n");

		return -EIO;

	}



	if (t->enabled) {

		reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;

		if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,

					      reg[M41T80_REG_ALARM_MON]) < 0) {

			dev_err(&client->dev, "write error\n");

			return -EIO;

		}

	}

	return 0;

}



static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)

{

	struct i2c_client *client = to_i2c_client(dev);

	u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */

	u8 dt_addr[1] = { M41T80_REG_ALARM_MON };

	u8 *reg = buf - M41T80_REG_ALARM_MON;

	struct i2c_msg msgs[] = {

		{

			.addr	= client->addr,

			.flags	= 0,

			.len	= 1,

			.buf	= dt_addr,

		},

		{

			.addr	= client->addr,

			.flags	= I2C_M_RD,

			.len	= M41T80_ALARM_REG_SIZE + 1,

			.buf	= buf,

		},

	};



	if (i2c_transfer(client->adapter, msgs, 2) < 0) {

		dev_err(&client->dev, "read error\n");

		return -EIO;

	}

	t->time.tm_sec = -1;

	t->time.tm_min = -1;

	t->time.tm_hour = -1;

	t->time.tm_mday = -1;

	t->time.tm_mon = -1;

	if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))

		t->time.tm_sec = BCD2BIN(reg[M41T80_REG_ALARM_SEC] & 0x7f);

	if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))

		t->time.tm_min = BCD2BIN(reg[M41T80_REG_ALARM_MIN] & 0x7f);

	if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))

		t->time.tm_hour = BCD2BIN(reg[M41T80_REG_ALARM_HOUR] & 0x3f);

	if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))

		t->time.tm_mday = BCD2BIN(reg[M41T80_REG_ALARM_DAY] & 0x3f);

	if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))

		t->time.tm_mon = BCD2BIN(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;

	t->time.tm_year = -1;

	t->time.tm_wday = -1;

	t->time.tm_yday = -1;

	t->time.tm_isdst = -1;

	t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);

	t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);

	return 0;

}



static struct rtc_class_ops m41t80_rtc_ops = {

	.read_time = m41t80_rtc_read_time,

	.set_time = m41t80_rtc_set_time,

	.read_alarm = m41t80_rtc_read_alarm,

	.set_alarm = m41t80_rtc_set_alarm,

	.proc = m41t80_rtc_proc,

	.ioctl = m41t80_rtc_ioctl,

};



#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)

static ssize_t m41t80_sysfs_show_flags(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	int val;



	val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);

	if (val < 0)

		return -EIO;

	return sprintf(buf, "%#x\n", val);

}

static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);



static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct i2c_client *client = to_i2c_client(dev);

	int val;



	val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);

	if (val < 0)

		return -EIO;

	val = (val >> 4) & 0xf;

	switch (val) {

	case 0:

		break;

	case 1:

		val = 32768;

		break;

	default:

		val = 32768 >> val;

	}

	return sprintf(buf, "%d\n", val);

}

static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,

				struct device_attribute *attr,

				const char *buf, size_t count)

{

	struct i2c_client *client = to_i2c_client(dev);

	int almon, sqw;

	int val = simple_strtoul(buf, NULL, 0);



	if (val) {

		if (!is_power_of_2(val))

			return -EINVAL;

		val = ilog2(val);

		if (val == 15)

			val = 1;

		else if (val < 14)

			val = 15 - val;

		else

			return -EINVAL;

	}

	/* disable SQW, set SQW frequency & re-enable */

	almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);

	if (almon < 0)

		return -EIO;

	sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);

	if (sqw < 0)

		return -EIO;

	sqw = (sqw & 0x0f) | (val << 4);

	if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,

				      almon & ~M41T80_ALMON_SQWE) < 0 ||

	    i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)

		return -EIO;

	if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,

					     almon | M41T80_ALMON_SQWE) < 0)

		return -EIO;

	return count;

}

static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,

		   m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);



static struct attribute *attrs[] = {

	&dev_attr_flags.attr,

	&dev_attr_sqwfreq.attr,

	NULL,

};

static struct attribute_group attr_group = {

	.attrs = attrs,

};



static int m41t80_sysfs_register(struct device *dev)

{

	return sysfs_create_group(&dev->kobj, &attr_group);

}

#else

static int m41t80_sysfs_register(struct device *dev)

{

	return 0;

}

#endif



/*

 *****************************************************************************

 *

 *	Driver Interface

 *

 *****************************************************************************

 */

static int m41t80_probe(struct i2c_client *client)

{

	int i, rc = 0;

	struct rtc_device *rtc = NULL;

	struct rtc_time tm;

	const struct m41t80_chip_info *chip;

	struct m41t80_data *clientdata = NULL;



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C

				     | I2C_FUNC_SMBUS_BYTE_DATA)) {

		rc = -ENODEV;

		goto exit;

	}



	dev_info(&client->dev,

		 "chip found, driver version " DRV_VERSION "\n");



	chip = NULL;

	for (i = 0; i < ARRAY_SIZE(m41t80_chip_info_tbl); i++) {

		if (!strcmp(m41t80_chip_info_tbl[i].name, client->name)) {

			chip = &m41t80_chip_info_tbl[i];

			break;

		}

	}

	if (!chip) {

		dev_err(&client->dev, "%s is not supported\n", client->name);

		rc = -ENODEV;

		goto exit;

	}



	clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);

	if (!clientdata) {

		rc = -ENOMEM;

		goto exit;

	}



	rtc = rtc_device_register(client->name, &client->dev,

				  &m41t80_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc)) {

		rc = PTR_ERR(rtc);

		rtc = NULL;

		goto exit;

	}



	clientdata->rtc = rtc;

	clientdata->chip = chip;

	i2c_set_clientdata(client, clientdata);



	/* Make sure HT (Halt Update) bit is cleared */

	rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);

	if (rc < 0)

		goto ht_err;



	if (rc & M41T80_ALHOUR_HT) {

		if (chip->features & M41T80_FEATURE_HT) {

			m41t80_get_datetime(client, &tm);

			dev_info(&client->dev, "HT bit was set!\n");

			dev_info(&client->dev,

				 "Power Down at "

				 "%04i-%02i-%02i %02i:%02i:%02i\n",

				 tm.tm_year + 1900,

				 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,

				 tm.tm_min, tm.tm_sec);

		}

		if (i2c_smbus_write_byte_data(client,

					      M41T80_REG_ALARM_HOUR,

					      rc & ~M41T80_ALHOUR_HT) < 0)

			goto ht_err;

	}



	/* Make sure ST (stop) bit is cleared */

	rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);

	if (rc < 0)

		goto st_err;



	if (rc & M41T80_SEC_ST) {

		if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,

					      rc & ~M41T80_SEC_ST) < 0)

			goto st_err;

	}



	rc = m41t80_sysfs_register(&client->dev);

	if (rc)

		goto exit;



	return 0;



st_err:

	rc = -EIO;

	dev_err(&client->dev, "Can't clear ST bit\n");

	goto exit;

ht_err:

	rc = -EIO;

	dev_err(&client->dev, "Can't clear HT bit\n");

	goto exit;



exit:

	if (rtc)

		rtc_device_unregister(rtc);

	kfree(clientdata);

	return rc;

}



static int m41t80_remove(struct i2c_client *client)

{

	struct m41t80_data *clientdata = i2c_get_clientdata(client);

	struct rtc_device *rtc = clientdata->rtc;



	if (rtc)

		rtc_device_unregister(rtc);

	kfree(clientdata);



	return 0;

}



static struct i2c_driver m41t80_driver = {

	.driver = {

		.name = "m41t80",

	},

	.probe = m41t80_probe,

	.remove = m41t80_remove,

};



static int __init m41t80_rtc_init(void)

{

	return i2c_add_driver(&m41t80_driver);

}



static void __exit m41t80_rtc_exit(void)

{

	i2c_del_driver(&m41t80_driver);

}



MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");

MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(DRV_VERSION);



module_init(m41t80_rtc_init);

module_exit(m41t80_rtc_exit);