2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
4 * Author: Alexander Bigga <ab@mycable.de>
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
8 * 2006 (c) mycable GmbH
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/bcd.h>
19 #include <linux/i2c.h>
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/rtc.h>
24 #include <linux/slab.h>
25 #include <linux/mutex.h>
26 #include <linux/string.h>
27 #ifdef CONFIG_RTC_DRV_M41T80_WDT
29 #include <linux/ioctl.h>
30 #include <linux/miscdevice.h>
31 #include <linux/reboot.h>
32 #include <linux/watchdog.h>
35 #define M41T80_REG_SSEC 0x00
36 #define M41T80_REG_SEC 0x01
37 #define M41T80_REG_MIN 0x02
38 #define M41T80_REG_HOUR 0x03
39 #define M41T80_REG_WDAY 0x04
40 #define M41T80_REG_DAY 0x05
41 #define M41T80_REG_MON 0x06
42 #define M41T80_REG_YEAR 0x07
43 #define M41T80_REG_ALARM_MON 0x0a
44 #define M41T80_REG_ALARM_DAY 0x0b
45 #define M41T80_REG_ALARM_HOUR 0x0c
46 #define M41T80_REG_ALARM_MIN 0x0d
47 #define M41T80_REG_ALARM_SEC 0x0e
48 #define M41T80_REG_FLAGS 0x0f
49 #define M41T80_REG_SQW 0x13
51 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
52 #define M41T80_ALARM_REG_SIZE \
53 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
55 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
56 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
57 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
58 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
59 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
60 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
61 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
62 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
63 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
64 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
66 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */
67 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
68 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
69 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
70 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
72 static DEFINE_MUTEX(m41t80_rtc_mutex);
73 static const struct i2c_device_id m41t80_id[] = {
74 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
75 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
76 { "m41t80", M41T80_FEATURE_SQ },
77 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
78 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
84 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
87 MODULE_DEVICE_TABLE(i2c, m41t80_id);
91 struct rtc_device *rtc;
94 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
96 struct i2c_client *client = dev_id;
97 struct m41t80_data *m41t80 = i2c_get_clientdata(client);
98 struct mutex *lock = &m41t80->rtc->ops_lock;
99 unsigned long events = 0;
100 int flags, flags_afe;
104 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
110 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
116 if (flags & M41T80_FLAGS_AF) {
117 flags &= ~M41T80_FLAGS_AF;
118 flags_afe &= ~M41T80_ALMON_AFE;
123 rtc_update_irq(m41t80->rtc, 1, events);
124 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
125 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
134 static int m41t80_get_datetime(struct i2c_client *client,
137 unsigned char buf[8];
140 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
144 if (flags & M41T80_FLAGS_OF) {
145 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
149 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
152 dev_err(&client->dev, "Unable to read date\n");
156 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
157 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
158 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
159 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
160 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
161 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
163 /* assume 20YY not 19YY, and ignore the Century Bit */
164 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
165 return rtc_valid_tm(tm);
168 /* Sets the given date and time to the real time clock. */
169 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
171 struct m41t80_data *clientdata = i2c_get_clientdata(client);
172 unsigned char buf[8];
175 if (tm->tm_year < 100 || tm->tm_year > 199)
178 buf[M41T80_REG_SSEC] = 0;
179 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
180 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
181 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
182 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
183 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
184 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
185 buf[M41T80_REG_WDAY] = tm->tm_wday;
187 /* If the square wave output is controlled in the weekday register */
188 if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
191 val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
195 buf[M41T80_REG_WDAY] |= (val & 0xf0);
198 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
201 dev_err(&client->dev, "Unable to write to date registers\n");
205 /* Clear the OF bit of Flags Register */
206 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
210 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
211 flags & ~M41T80_FLAGS_OF)) {
212 dev_err(&client->dev, "Unable to write flags register\n");
219 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
221 struct i2c_client *client = to_i2c_client(dev);
222 struct m41t80_data *clientdata = i2c_get_clientdata(client);
225 if (clientdata->features & M41T80_FEATURE_BL) {
226 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
227 seq_printf(seq, "battery\t\t: %s\n",
228 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
233 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
235 return m41t80_get_datetime(to_i2c_client(dev), tm);
238 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
240 return m41t80_set_datetime(to_i2c_client(dev), tm);
243 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
245 struct i2c_client *client = to_i2c_client(dev);
248 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
253 flags |= M41T80_ALMON_AFE;
255 flags &= ~M41T80_ALMON_AFE;
257 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
259 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
265 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
267 struct i2c_client *client = to_i2c_client(dev);
271 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
272 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
273 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
274 alarmvals[3] = bin2bcd(alrm->time.tm_min);
275 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
277 /* Clear AF and AFE flags */
278 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
281 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
282 ret & ~(M41T80_ALMON_AFE));
284 dev_err(dev, "Unable to clear AFE bit\n");
288 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
292 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
293 ret & ~(M41T80_FLAGS_AF));
295 dev_err(dev, "Unable to clear AF bit\n");
299 /* Write the alarm */
300 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
305 /* Enable the alarm interrupt */
307 alarmvals[0] |= M41T80_ALMON_AFE;
308 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
317 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
319 struct i2c_client *client = to_i2c_client(dev);
323 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
326 return ret < 0 ? ret : -EIO;
328 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
332 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
333 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
334 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
335 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
336 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1;
338 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
339 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
344 static struct rtc_class_ops m41t80_rtc_ops = {
345 .read_time = m41t80_rtc_read_time,
346 .set_time = m41t80_rtc_set_time,
347 .proc = m41t80_rtc_proc,
350 #ifdef CONFIG_PM_SLEEP
351 static int m41t80_suspend(struct device *dev)
353 struct i2c_client *client = to_i2c_client(dev);
355 if (client->irq >= 0 && device_may_wakeup(dev))
356 enable_irq_wake(client->irq);
361 static int m41t80_resume(struct device *dev)
363 struct i2c_client *client = to_i2c_client(dev);
365 if (client->irq >= 0 && device_may_wakeup(dev))
366 disable_irq_wake(client->irq);
372 static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
374 static ssize_t flags_show(struct device *dev,
375 struct device_attribute *attr, char *buf)
377 struct i2c_client *client = to_i2c_client(dev);
380 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
383 return sprintf(buf, "%#x\n", val);
385 static DEVICE_ATTR_RO(flags);
387 static ssize_t sqwfreq_show(struct device *dev,
388 struct device_attribute *attr, char *buf)
390 struct i2c_client *client = to_i2c_client(dev);
391 struct m41t80_data *clientdata = i2c_get_clientdata(client);
394 if (!(clientdata->features & M41T80_FEATURE_SQ))
397 reg_sqw = M41T80_REG_SQW;
398 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
399 reg_sqw = M41T80_REG_WDAY;
400 val = i2c_smbus_read_byte_data(client, reg_sqw);
403 val = (val >> 4) & 0xf;
413 return sprintf(buf, "%d\n", val);
416 static ssize_t sqwfreq_store(struct device *dev,
417 struct device_attribute *attr,
418 const char *buf, size_t count)
420 struct i2c_client *client = to_i2c_client(dev);
421 struct m41t80_data *clientdata = i2c_get_clientdata(client);
422 int almon, sqw, reg_sqw, rc;
425 rc = kstrtoul(buf, 0, &val);
429 if (!(clientdata->features & M41T80_FEATURE_SQ))
433 if (!is_power_of_2(val))
443 /* disable SQW, set SQW frequency & re-enable */
444 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
447 reg_sqw = M41T80_REG_SQW;
448 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
449 reg_sqw = M41T80_REG_WDAY;
450 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
453 sqw = (sqw & 0x0f) | (val << 4);
455 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
456 almon & ~M41T80_ALMON_SQWE);
461 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
465 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
466 almon | M41T80_ALMON_SQWE);
472 static DEVICE_ATTR_RW(sqwfreq);
474 static struct attribute *attrs[] = {
475 &dev_attr_flags.attr,
476 &dev_attr_sqwfreq.attr,
480 static struct attribute_group attr_group = {
484 #ifdef CONFIG_RTC_DRV_M41T80_WDT
486 *****************************************************************************
490 *****************************************************************************
492 static struct i2c_client *save_client;
495 #define WD_TIMO 60 /* 1..31 seconds */
497 static int wdt_margin = WD_TIMO;
498 module_param(wdt_margin, int, 0);
499 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
501 static unsigned long wdt_is_open;
502 static int boot_flag;
507 * Reload counter one with the watchdog timeout. We don't bother reloading
508 * the cascade counter.
510 static void wdt_ping(void)
512 unsigned char i2c_data[2];
513 struct i2c_msg msgs1[1] = {
515 .addr = save_client->addr,
521 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
523 i2c_data[0] = 0x09; /* watchdog register */
526 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
529 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
531 i2c_data[1] = wdt_margin << 2 | 0x82;
534 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
535 * that would be an invalid resolution.
537 if (clientdata->features & M41T80_FEATURE_WD)
538 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
540 i2c_transfer(save_client->adapter, msgs1, 1);
548 static void wdt_disable(void)
550 unsigned char i2c_data[2], i2c_buf[0x10];
551 struct i2c_msg msgs0[2] = {
553 .addr = save_client->addr,
559 .addr = save_client->addr,
565 struct i2c_msg msgs1[1] = {
567 .addr = save_client->addr,
575 i2c_transfer(save_client->adapter, msgs0, 2);
579 i2c_transfer(save_client->adapter, msgs1, 1);
584 * @file: file handle to the watchdog
585 * @buf: buffer to write (unused as data does not matter here
586 * @count: count of bytes
587 * @ppos: pointer to the position to write. No seeks allowed
589 * A write to a watchdog device is defined as a keepalive signal. Any
590 * write of data will do, as we we don't define content meaning.
592 static ssize_t wdt_write(struct file *file, const char __user *buf,
593 size_t count, loff_t *ppos)
602 static ssize_t wdt_read(struct file *file, char __user *buf,
603 size_t count, loff_t *ppos)
610 * @inode: inode of the device
611 * @file: file handle to the device
612 * @cmd: watchdog command
613 * @arg: argument pointer
615 * The watchdog API defines a common set of functions for all watchdogs
616 * according to their available features. We only actually usefully support
617 * querying capabilities and current status.
619 static int wdt_ioctl(struct file *file, unsigned int cmd,
623 static struct watchdog_info ident = {
624 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
626 .firmware_version = 1,
627 .identity = "M41T80 WTD"
631 case WDIOC_GETSUPPORT:
632 return copy_to_user((struct watchdog_info __user *)arg, &ident,
633 sizeof(ident)) ? -EFAULT : 0;
635 case WDIOC_GETSTATUS:
636 case WDIOC_GETBOOTSTATUS:
637 return put_user(boot_flag, (int __user *)arg);
638 case WDIOC_KEEPALIVE:
641 case WDIOC_SETTIMEOUT:
642 if (get_user(new_margin, (int __user *)arg))
644 /* Arbitrary, can't find the card's limits */
645 if (new_margin < 1 || new_margin > 124)
647 wdt_margin = new_margin;
650 case WDIOC_GETTIMEOUT:
651 return put_user(wdt_margin, (int __user *)arg);
653 case WDIOC_SETOPTIONS:
654 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
657 if (rv & WDIOS_DISABLECARD) {
658 pr_info("disable watchdog\n");
662 if (rv & WDIOS_ENABLECARD) {
663 pr_info("enable watchdog\n");
672 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
677 mutex_lock(&m41t80_rtc_mutex);
678 ret = wdt_ioctl(file, cmd, arg);
679 mutex_unlock(&m41t80_rtc_mutex);
686 * @inode: inode of device
687 * @file: file handle to device
690 static int wdt_open(struct inode *inode, struct file *file)
692 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
693 mutex_lock(&m41t80_rtc_mutex);
694 if (test_and_set_bit(0, &wdt_is_open)) {
695 mutex_unlock(&m41t80_rtc_mutex);
702 mutex_unlock(&m41t80_rtc_mutex);
703 return nonseekable_open(inode, file);
710 * @inode: inode to board
711 * @file: file handle to board
714 static int wdt_release(struct inode *inode, struct file *file)
716 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
717 clear_bit(0, &wdt_is_open);
723 * @this: our notifier block
724 * @code: the event being reported
727 * Our notifier is called on system shutdowns. We want to turn the card
728 * off at reboot otherwise the machine will reboot again during memory
729 * test or worse yet during the following fsck. This would suck, in fact
730 * trust me - if it happens it does suck.
732 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
735 if (code == SYS_DOWN || code == SYS_HALT)
736 /* Disable Watchdog */
741 static const struct file_operations wdt_fops = {
742 .owner = THIS_MODULE,
744 .unlocked_ioctl = wdt_unlocked_ioctl,
747 .release = wdt_release,
751 static struct miscdevice wdt_dev = {
752 .minor = WATCHDOG_MINOR,
758 * The WDT card needs to learn about soft shutdowns in order to
759 * turn the timebomb registers off.
761 static struct notifier_block wdt_notifier = {
762 .notifier_call = wdt_notify_sys,
764 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
767 *****************************************************************************
771 *****************************************************************************
774 static void m41t80_remove_sysfs_group(void *_dev)
776 struct device *dev = _dev;
778 sysfs_remove_group(&dev->kobj, &attr_group);
781 static int m41t80_probe(struct i2c_client *client,
782 const struct i2c_device_id *id)
784 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
786 struct rtc_device *rtc = NULL;
788 struct m41t80_data *m41t80_data = NULL;
790 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
791 I2C_FUNC_SMBUS_BYTE_DATA)) {
792 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
796 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
801 m41t80_data->features = id->driver_data;
802 i2c_set_clientdata(client, m41t80_data);
804 if (client->irq > 0) {
805 rc = devm_request_threaded_irq(&client->dev, client->irq,
806 NULL, m41t80_handle_irq,
807 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
810 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
813 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
814 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
815 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
816 /* Enable the wakealarm */
817 device_init_wakeup(&client->dev, true);
821 rtc = devm_rtc_device_register(&client->dev, client->name,
822 &m41t80_rtc_ops, THIS_MODULE);
826 m41t80_data->rtc = rtc;
828 /* Make sure HT (Halt Update) bit is cleared */
829 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
831 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
832 if (m41t80_data->features & M41T80_FEATURE_HT) {
833 m41t80_get_datetime(client, &tm);
834 dev_info(&client->dev, "HT bit was set!\n");
835 dev_info(&client->dev,
836 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
838 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
839 tm.tm_min, tm.tm_sec);
841 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
842 rc & ~M41T80_ALHOUR_HT);
846 dev_err(&client->dev, "Can't clear HT bit\n");
850 /* Make sure ST (stop) bit is cleared */
851 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
853 if (rc >= 0 && rc & M41T80_SEC_ST)
854 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
855 rc & ~M41T80_SEC_ST);
857 dev_err(&client->dev, "Can't clear ST bit\n");
861 /* Export sysfs entries */
862 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
864 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
868 rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group,
871 dev_err(&client->dev,
872 "Failed to add sysfs cleanup action: %d\n", rc);
876 #ifdef CONFIG_RTC_DRV_M41T80_WDT
877 if (m41t80_data->features & M41T80_FEATURE_HT) {
878 save_client = client;
879 rc = misc_register(&wdt_dev);
882 rc = register_reboot_notifier(&wdt_notifier);
884 misc_deregister(&wdt_dev);
892 static int m41t80_remove(struct i2c_client *client)
894 #ifdef CONFIG_RTC_DRV_M41T80_WDT
895 struct m41t80_data *clientdata = i2c_get_clientdata(client);
897 if (clientdata->features & M41T80_FEATURE_HT) {
898 misc_deregister(&wdt_dev);
899 unregister_reboot_notifier(&wdt_notifier);
906 static struct i2c_driver m41t80_driver = {
908 .name = "rtc-m41t80",
911 .probe = m41t80_probe,
912 .remove = m41t80_remove,
913 .id_table = m41t80_id,
916 module_i2c_driver(m41t80_driver);
918 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
919 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
920 MODULE_LICENSE("GPL");