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* I2C client/driver for the ST M41T80 family of i2c rtc chips.
4
* Author: Alexander Bigga <ab@mycable.de>
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* Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
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* 2006 (c) mycable GmbH
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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#include <linux/bcd.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/string.h>
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#ifdef CONFIG_RTC_DRV_M41T80_WDT
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#include <linux/ioctl.h>
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#include <linux/miscdevice.h>
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#include <linux/reboot.h>
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#include <linux/watchdog.h>
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#define M41T80_REG_SSEC 0
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#define M41T80_REG_SEC 1
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#define M41T80_REG_MIN 2
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#define M41T80_REG_HOUR 3
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#define M41T80_REG_WDAY 4
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#define M41T80_REG_DAY 5
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#define M41T80_REG_MON 6
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#define M41T80_REG_YEAR 7
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#define M41T80_REG_ALARM_MON 0xa
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#define M41T80_REG_ALARM_DAY 0xb
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#define M41T80_REG_ALARM_HOUR 0xc
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#define M41T80_REG_ALARM_MIN 0xd
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#define M41T80_REG_ALARM_SEC 0xe
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#define M41T80_REG_FLAGS 0xf
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#define M41T80_REG_SQW 0x13
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#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
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#define M41T80_ALARM_REG_SIZE \
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(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
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#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
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#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
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#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
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#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
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#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
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#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
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#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
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#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
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#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
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#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
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#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
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#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
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#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
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#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
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#define DRV_VERSION "0.05"
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static DEFINE_MUTEX(m41t80_rtc_mutex);
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static const struct i2c_device_id m41t80_id[] = {
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{ "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
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{ "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
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{ "m41t80", M41T80_FEATURE_SQ },
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{ "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
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{ "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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{ "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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{ "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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{ "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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{ "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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{ "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
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MODULE_DEVICE_TABLE(i2c, m41t80_id);
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struct rtc_device *rtc;
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static int m41t80_get_datetime(struct i2c_client *client,
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u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
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struct i2c_msg msgs[] = {
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.addr = client->addr,
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.len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
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.buf = buf + M41T80_REG_SEC,
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if (i2c_transfer(client->adapter, msgs, 2) < 0) {
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dev_err(&client->dev, "read error\n");
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tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
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tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
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tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
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tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
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tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
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tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
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/* assume 20YY not 19YY, and ignore the Century Bit */
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tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
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return rtc_valid_tm(tm);
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/* Sets the given date and time to the real time clock. */
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static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
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u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
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u8 dt_addr[1] = { M41T80_REG_SEC };
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struct i2c_msg msgs_in[] = {
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.addr = client->addr,
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.addr = client->addr,
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.len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
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.buf = buf + M41T80_REG_SEC,
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struct i2c_msg msgs[] = {
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.addr = client->addr,
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.len = 1 + M41T80_DATETIME_REG_SIZE,
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/* Read current reg values into buf[1..7] */
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if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
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dev_err(&client->dev, "read error\n");
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wbuf[0] = 0; /* offset into rtc's regs */
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/* Merge time-data and register flags into buf[0..7] */
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buf[M41T80_REG_SSEC] = 0;
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buf[M41T80_REG_SEC] =
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bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
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buf[M41T80_REG_MIN] =
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bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
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buf[M41T80_REG_HOUR] =
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bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
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buf[M41T80_REG_WDAY] =
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(tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
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buf[M41T80_REG_DAY] =
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bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
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buf[M41T80_REG_MON] =
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bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
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/* assume 20YY not 19YY */
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buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
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if (i2c_transfer(client->adapter, msgs, 1) != 1) {
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dev_err(&client->dev, "write error\n");
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#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
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static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
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struct i2c_client *client = to_i2c_client(dev);
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struct m41t80_data *clientdata = i2c_get_clientdata(client);
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if (clientdata->features & M41T80_FEATURE_BL) {
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reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
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seq_printf(seq, "battery\t\t: %s\n",
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(reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
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#define m41t80_rtc_proc NULL
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static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
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return m41t80_get_datetime(to_i2c_client(dev), tm);
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static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
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return m41t80_set_datetime(to_i2c_client(dev), tm);
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static int m41t80_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
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struct i2c_client *client = to_i2c_client(dev);
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rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
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rc |= M41T80_ALMON_AFE;
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rc &= ~M41T80_ALMON_AFE;
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if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
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static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
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struct i2c_client *client = to_i2c_client(dev);
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u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
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u8 *reg = buf - M41T80_REG_ALARM_MON;
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u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
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struct i2c_msg msgs_in[] = {
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.addr = client->addr,
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.addr = client->addr,
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.len = M41T80_ALARM_REG_SIZE,
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struct i2c_msg msgs[] = {
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.addr = client->addr,
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.len = 1 + M41T80_ALARM_REG_SIZE,
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if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
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dev_err(&client->dev, "read error\n");
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reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
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reg[M41T80_REG_ALARM_DAY] = 0;
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reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
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reg[M41T80_REG_ALARM_MIN] = 0;
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reg[M41T80_REG_ALARM_SEC] = 0;
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wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
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reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
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bin2bcd(t->time.tm_sec) : 0x80;
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reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
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bin2bcd(t->time.tm_min) : 0x80;
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reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
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bin2bcd(t->time.tm_hour) : 0x80;
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reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
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bin2bcd(t->time.tm_mday) : 0x80;
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if (t->time.tm_mon >= 0)
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reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
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reg[M41T80_REG_ALARM_DAY] |= 0x40;
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if (i2c_transfer(client->adapter, msgs, 1) != 1) {
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dev_err(&client->dev, "write error\n");
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reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
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if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
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reg[M41T80_REG_ALARM_MON]) < 0) {
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dev_err(&client->dev, "write error\n");
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static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
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struct i2c_client *client = to_i2c_client(dev);
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u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
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u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
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u8 *reg = buf - M41T80_REG_ALARM_MON;
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struct i2c_msg msgs[] = {
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.addr = client->addr,
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.addr = client->addr,
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.len = M41T80_ALARM_REG_SIZE + 1,
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if (i2c_transfer(client->adapter, msgs, 2) < 0) {
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dev_err(&client->dev, "read error\n");
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t->time.tm_hour = -1;
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t->time.tm_mday = -1;
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if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
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t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
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if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
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t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
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if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
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t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
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if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
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t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
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if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
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t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
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t->time.tm_year = -1;
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t->time.tm_wday = -1;
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t->time.tm_yday = -1;
351
t->time.tm_isdst = -1;
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t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
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t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
357
static struct rtc_class_ops m41t80_rtc_ops = {
358
.read_time = m41t80_rtc_read_time,
359
.set_time = m41t80_rtc_set_time,
361
* XXX - m41t80 alarm functionality is reported broken.
362
* until it is fixed, don't register alarm functions.
364
.read_alarm = m41t80_rtc_read_alarm,
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.set_alarm = m41t80_rtc_set_alarm,
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.proc = m41t80_rtc_proc,
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* See above comment on broken alarm
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.alarm_irq_enable = m41t80_rtc_alarm_irq_enable,
375
#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
376
static ssize_t m41t80_sysfs_show_flags(struct device *dev,
377
struct device_attribute *attr, char *buf)
379
struct i2c_client *client = to_i2c_client(dev);
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val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
385
return sprintf(buf, "%#x\n", val);
387
static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
389
static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
390
struct device_attribute *attr, char *buf)
392
struct i2c_client *client = to_i2c_client(dev);
393
struct m41t80_data *clientdata = i2c_get_clientdata(client);
396
if (!(clientdata->features & M41T80_FEATURE_SQ))
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reg_sqw = M41T80_REG_SQW;
400
if (clientdata->features & M41T80_FEATURE_SQ_ALT)
401
reg_sqw = M41T80_REG_WDAY;
402
val = i2c_smbus_read_byte_data(client, reg_sqw);
405
val = (val >> 4) & 0xf;
415
return sprintf(buf, "%d\n", val);
417
static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
418
struct device_attribute *attr,
419
const char *buf, size_t count)
421
struct i2c_client *client = to_i2c_client(dev);
422
struct m41t80_data *clientdata = i2c_get_clientdata(client);
423
int almon, sqw, reg_sqw;
424
int val = simple_strtoul(buf, NULL, 0);
426
if (!(clientdata->features & M41T80_FEATURE_SQ))
430
if (!is_power_of_2(val))
440
/* disable SQW, set SQW frequency & re-enable */
441
almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
444
reg_sqw = M41T80_REG_SQW;
445
if (clientdata->features & M41T80_FEATURE_SQ_ALT)
446
reg_sqw = M41T80_REG_WDAY;
447
sqw = i2c_smbus_read_byte_data(client, reg_sqw);
450
sqw = (sqw & 0x0f) | (val << 4);
451
if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
452
almon & ~M41T80_ALMON_SQWE) < 0 ||
453
i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
455
if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
456
almon | M41T80_ALMON_SQWE) < 0)
460
static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
461
m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
463
static struct attribute *attrs[] = {
464
&dev_attr_flags.attr,
465
&dev_attr_sqwfreq.attr,
468
static struct attribute_group attr_group = {
472
static int m41t80_sysfs_register(struct device *dev)
474
return sysfs_create_group(&dev->kobj, &attr_group);
477
static int m41t80_sysfs_register(struct device *dev)
483
#ifdef CONFIG_RTC_DRV_M41T80_WDT
485
*****************************************************************************
489
*****************************************************************************
491
static struct i2c_client *save_client;
494
#define WD_TIMO 60 /* 1..31 seconds */
496
static int wdt_margin = WD_TIMO;
497
module_param(wdt_margin, int, 0);
498
MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
500
static unsigned long wdt_is_open;
501
static int boot_flag;
506
* Reload counter one with the watchdog timeout. We don't bother reloading
507
* the cascade counter.
509
static void wdt_ping(void)
511
unsigned char i2c_data[2];
512
struct i2c_msg msgs1[1] = {
514
.addr = save_client->addr,
520
struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
522
i2c_data[0] = 0x09; /* watchdog register */
525
i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
528
* WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
530
i2c_data[1] = wdt_margin<<2 | 0x82;
533
* M41T65 has three bits for watchdog resolution. Don't set bit 7, as
534
* that would be an invalid resolution.
536
if (clientdata->features & M41T80_FEATURE_WD)
537
i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
539
i2c_transfer(save_client->adapter, msgs1, 1);
547
static void wdt_disable(void)
549
unsigned char i2c_data[2], i2c_buf[0x10];
550
struct i2c_msg msgs0[2] = {
552
.addr = save_client->addr,
558
.addr = save_client->addr,
564
struct i2c_msg msgs1[1] = {
566
.addr = save_client->addr,
574
i2c_transfer(save_client->adapter, msgs0, 2);
578
i2c_transfer(save_client->adapter, msgs1, 1);
583
* @file: file handle to the watchdog
584
* @buf: buffer to write (unused as data does not matter here
585
* @count: count of bytes
586
* @ppos: pointer to the position to write. No seeks allowed
588
* A write to a watchdog device is defined as a keepalive signal. Any
589
* write of data will do, as we we don't define content meaning.
591
static ssize_t wdt_write(struct file *file, const char __user *buf,
592
size_t count, loff_t *ppos)
601
static ssize_t wdt_read(struct file *file, char __user *buf,
602
size_t count, loff_t *ppos)
609
* @inode: inode of the device
610
* @file: file handle to the device
611
* @cmd: watchdog command
612
* @arg: argument pointer
614
* The watchdog API defines a common set of functions for all watchdogs
615
* according to their available features. We only actually usefully support
616
* querying capabilities and current status.
618
static int wdt_ioctl(struct file *file, unsigned int cmd,
622
static struct watchdog_info ident = {
623
.options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
625
.firmware_version = 1,
626
.identity = "M41T80 WTD"
630
case WDIOC_GETSUPPORT:
631
return copy_to_user((struct watchdog_info __user *)arg, &ident,
632
sizeof(ident)) ? -EFAULT : 0;
634
case WDIOC_GETSTATUS:
635
case WDIOC_GETBOOTSTATUS:
636
return put_user(boot_flag, (int __user *)arg);
637
case WDIOC_KEEPALIVE:
640
case WDIOC_SETTIMEOUT:
641
if (get_user(new_margin, (int __user *)arg))
643
/* Arbitrary, can't find the card's limits */
644
if (new_margin < 1 || new_margin > 124)
646
wdt_margin = new_margin;
649
case WDIOC_GETTIMEOUT:
650
return put_user(wdt_margin, (int __user *)arg);
652
case WDIOC_SETOPTIONS:
653
if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
656
if (rv & WDIOS_DISABLECARD) {
657
pr_info("rtc-m41t80: disable watchdog\n");
661
if (rv & WDIOS_ENABLECARD) {
662
pr_info("rtc-m41t80: enable watchdog\n");
671
static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
676
mutex_lock(&m41t80_rtc_mutex);
677
ret = wdt_ioctl(file, cmd, arg);
678
mutex_unlock(&m41t80_rtc_mutex);
685
* @inode: inode of device
686
* @file: file handle to device
689
static int wdt_open(struct inode *inode, struct file *file)
691
if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
692
mutex_lock(&m41t80_rtc_mutex);
693
if (test_and_set_bit(0, &wdt_is_open)) {
694
mutex_unlock(&m41t80_rtc_mutex);
701
mutex_unlock(&m41t80_rtc_mutex);
702
return nonseekable_open(inode, file);
709
* @inode: inode to board
710
* @file: file handle to board
713
static int wdt_release(struct inode *inode, struct file *file)
715
if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
716
clear_bit(0, &wdt_is_open);
722
* @this: our notifier block
723
* @code: the event being reported
726
* Our notifier is called on system shutdowns. We want to turn the card
727
* off at reboot otherwise the machine will reboot again during memory
728
* test or worse yet during the following fsck. This would suck, in fact
729
* trust me - if it happens it does suck.
731
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
734
if (code == SYS_DOWN || code == SYS_HALT)
735
/* Disable Watchdog */
740
static const struct file_operations wdt_fops = {
741
.owner = THIS_MODULE,
743
.unlocked_ioctl = wdt_unlocked_ioctl,
746
.release = wdt_release,
750
static struct miscdevice wdt_dev = {
751
.minor = WATCHDOG_MINOR,
757
* The WDT card needs to learn about soft shutdowns in order to
758
* turn the timebomb registers off.
760
static struct notifier_block wdt_notifier = {
761
.notifier_call = wdt_notify_sys,
763
#endif /* CONFIG_RTC_DRV_M41T80_WDT */
766
*****************************************************************************
770
*****************************************************************************
772
static int m41t80_probe(struct i2c_client *client,
773
const struct i2c_device_id *id)
776
struct rtc_device *rtc = NULL;
778
struct m41t80_data *clientdata = NULL;
780
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
781
| I2C_FUNC_SMBUS_BYTE_DATA)) {
786
dev_info(&client->dev,
787
"chip found, driver version " DRV_VERSION "\n");
789
clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
795
clientdata->features = id->driver_data;
796
i2c_set_clientdata(client, clientdata);
798
rtc = rtc_device_register(client->name, &client->dev,
799
&m41t80_rtc_ops, THIS_MODULE);
806
clientdata->rtc = rtc;
808
/* Make sure HT (Halt Update) bit is cleared */
809
rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
813
if (rc & M41T80_ALHOUR_HT) {
814
if (clientdata->features & M41T80_FEATURE_HT) {
815
m41t80_get_datetime(client, &tm);
816
dev_info(&client->dev, "HT bit was set!\n");
817
dev_info(&client->dev,
819
"%04i-%02i-%02i %02i:%02i:%02i\n",
821
tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
822
tm.tm_min, tm.tm_sec);
824
if (i2c_smbus_write_byte_data(client,
825
M41T80_REG_ALARM_HOUR,
826
rc & ~M41T80_ALHOUR_HT) < 0)
830
/* Make sure ST (stop) bit is cleared */
831
rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
835
if (rc & M41T80_SEC_ST) {
836
if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
837
rc & ~M41T80_SEC_ST) < 0)
841
rc = m41t80_sysfs_register(&client->dev);
845
#ifdef CONFIG_RTC_DRV_M41T80_WDT
846
if (clientdata->features & M41T80_FEATURE_HT) {
847
save_client = client;
848
rc = misc_register(&wdt_dev);
851
rc = register_reboot_notifier(&wdt_notifier);
853
misc_deregister(&wdt_dev);
862
dev_err(&client->dev, "Can't clear ST bit\n");
866
dev_err(&client->dev, "Can't clear HT bit\n");
871
rtc_device_unregister(rtc);
876
static int m41t80_remove(struct i2c_client *client)
878
struct m41t80_data *clientdata = i2c_get_clientdata(client);
879
struct rtc_device *rtc = clientdata->rtc;
881
#ifdef CONFIG_RTC_DRV_M41T80_WDT
882
if (clientdata->features & M41T80_FEATURE_HT) {
883
misc_deregister(&wdt_dev);
884
unregister_reboot_notifier(&wdt_notifier);
888
rtc_device_unregister(rtc);
894
static struct i2c_driver m41t80_driver = {
896
.name = "rtc-m41t80",
898
.probe = m41t80_probe,
899
.remove = m41t80_remove,
900
.id_table = m41t80_id,
903
static int __init m41t80_rtc_init(void)
905
return i2c_add_driver(&m41t80_driver);
908
static void __exit m41t80_rtc_exit(void)
910
i2c_del_driver(&m41t80_driver);
913
MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
914
MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
915
MODULE_LICENSE("GPL");
916
MODULE_VERSION(DRV_VERSION);
918
module_init(m41t80_rtc_init);
919
module_exit(m41t80_rtc_exit);