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_AF BIT(6) /* AF: Alarm Flag Bit */
60 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
61 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
62 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
63 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
65 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */
66 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
67 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
68 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
69 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
71 static DEFINE_MUTEX(m41t80_rtc_mutex
);
72 static const struct i2c_device_id m41t80_id
[] = {
73 { "m41t62", M41T80_FEATURE_SQ
| M41T80_FEATURE_SQ_ALT
},
74 { "m41t65", M41T80_FEATURE_HT
| M41T80_FEATURE_WD
},
75 { "m41t80", M41T80_FEATURE_SQ
},
76 { "m41t81", M41T80_FEATURE_HT
| M41T80_FEATURE_SQ
},
77 { "m41t81s", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
78 { "m41t82", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
79 { "m41t83", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
80 { "m41st84", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
81 { "m41st85", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
82 { "m41st87", M41T80_FEATURE_HT
| M41T80_FEATURE_BL
| M41T80_FEATURE_SQ
},
83 { "rv4162", M41T80_FEATURE_SQ
| M41T80_FEATURE_WD
| M41T80_FEATURE_SQ_ALT
},
86 MODULE_DEVICE_TABLE(i2c
, m41t80_id
);
90 struct rtc_device
*rtc
;
93 static irqreturn_t
m41t80_handle_irq(int irq
, void *dev_id
)
95 struct i2c_client
*client
= dev_id
;
96 struct m41t80_data
*m41t80
= i2c_get_clientdata(client
);
97 struct mutex
*lock
= &m41t80
->rtc
->ops_lock
;
98 unsigned long events
= 0;
103 flags_afe
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
109 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
115 if (flags
& M41T80_FLAGS_AF
) {
116 flags
&= ~M41T80_FLAGS_AF
;
117 flags_afe
&= ~M41T80_ALMON_AFE
;
122 rtc_update_irq(m41t80
->rtc
, 1, events
);
123 i2c_smbus_write_byte_data(client
, M41T80_REG_FLAGS
, flags
);
124 i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
133 static int m41t80_get_datetime(struct i2c_client
*client
,
136 unsigned char buf
[8];
139 err
= i2c_smbus_read_i2c_block_data(client
, M41T80_REG_SSEC
,
142 dev_err(&client
->dev
, "Unable to read date\n");
146 tm
->tm_sec
= bcd2bin(buf
[M41T80_REG_SEC
] & 0x7f);
147 tm
->tm_min
= bcd2bin(buf
[M41T80_REG_MIN
] & 0x7f);
148 tm
->tm_hour
= bcd2bin(buf
[M41T80_REG_HOUR
] & 0x3f);
149 tm
->tm_mday
= bcd2bin(buf
[M41T80_REG_DAY
] & 0x3f);
150 tm
->tm_wday
= buf
[M41T80_REG_WDAY
] & 0x07;
151 tm
->tm_mon
= bcd2bin(buf
[M41T80_REG_MON
] & 0x1f) - 1;
153 /* assume 20YY not 19YY, and ignore the Century Bit */
154 tm
->tm_year
= bcd2bin(buf
[M41T80_REG_YEAR
]) + 100;
155 return rtc_valid_tm(tm
);
158 /* Sets the given date and time to the real time clock. */
159 static int m41t80_set_datetime(struct i2c_client
*client
, struct rtc_time
*tm
)
161 unsigned char buf
[8];
164 if (tm
->tm_year
< 100 || tm
->tm_year
> 199)
167 buf
[M41T80_REG_SSEC
] = 0;
168 buf
[M41T80_REG_SEC
] = bin2bcd(tm
->tm_sec
);
169 buf
[M41T80_REG_MIN
] = bin2bcd(tm
->tm_min
);
170 buf
[M41T80_REG_HOUR
] = bin2bcd(tm
->tm_hour
);
171 buf
[M41T80_REG_DAY
] = bin2bcd(tm
->tm_mday
);
172 buf
[M41T80_REG_MON
] = bin2bcd(tm
->tm_mon
+ 1);
173 buf
[M41T80_REG_YEAR
] = bin2bcd(tm
->tm_year
- 100);
174 buf
[M41T80_REG_WDAY
] = tm
->tm_wday
;
176 err
= i2c_smbus_write_i2c_block_data(client
, M41T80_REG_SSEC
,
179 dev_err(&client
->dev
, "Unable to write to date registers\n");
186 static int m41t80_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
188 struct i2c_client
*client
= to_i2c_client(dev
);
189 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
192 if (clientdata
->features
& M41T80_FEATURE_BL
) {
193 reg
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
194 seq_printf(seq
, "battery\t\t: %s\n",
195 (reg
& M41T80_FLAGS_BATT_LOW
) ? "exhausted" : "ok");
200 static int m41t80_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
202 return m41t80_get_datetime(to_i2c_client(dev
), tm
);
205 static int m41t80_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
207 return m41t80_set_datetime(to_i2c_client(dev
), tm
);
210 static int m41t80_alarm_irq_enable(struct device
*dev
, unsigned int enabled
)
212 struct i2c_client
*client
= to_i2c_client(dev
);
215 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
220 flags
|= M41T80_ALMON_AFE
;
222 flags
&= ~M41T80_ALMON_AFE
;
224 retval
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
, flags
);
226 dev_info(dev
, "Unable to enable alarm IRQ %d\n", retval
);
232 static int m41t80_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
234 struct i2c_client
*client
= to_i2c_client(dev
);
238 alarmvals
[0] = bin2bcd(alrm
->time
.tm_mon
+ 1);
239 alarmvals
[1] = bin2bcd(alrm
->time
.tm_mday
);
240 alarmvals
[2] = bin2bcd(alrm
->time
.tm_hour
);
241 alarmvals
[3] = bin2bcd(alrm
->time
.tm_min
);
242 alarmvals
[4] = bin2bcd(alrm
->time
.tm_sec
);
244 /* Clear AF and AFE flags */
245 ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
248 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
249 ret
& ~(M41T80_ALMON_AFE
));
251 dev_err(dev
, "Unable to clear AFE bit\n");
255 ret
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
259 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_FLAGS
,
260 ret
& ~(M41T80_FLAGS_AF
));
262 dev_err(dev
, "Unable to clear AF bit\n");
266 /* Write the alarm */
267 err
= i2c_smbus_write_i2c_block_data(client
, M41T80_REG_ALARM_MON
,
272 /* Enable the alarm interrupt */
274 alarmvals
[0] |= M41T80_ALMON_AFE
;
275 err
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
284 static int m41t80_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
286 struct i2c_client
*client
= to_i2c_client(dev
);
290 ret
= i2c_smbus_read_i2c_block_data(client
, M41T80_REG_ALARM_MON
,
293 return ret
< 0 ? ret
: -EIO
;
295 flags
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
299 alrm
->time
.tm_sec
= bcd2bin(alarmvals
[4] & 0x7f);
300 alrm
->time
.tm_min
= bcd2bin(alarmvals
[3] & 0x7f);
301 alrm
->time
.tm_hour
= bcd2bin(alarmvals
[2] & 0x3f);
302 alrm
->time
.tm_wday
= -1;
303 alrm
->time
.tm_mday
= bcd2bin(alarmvals
[1] & 0x3f);
304 alrm
->time
.tm_mon
= bcd2bin(alarmvals
[0] & 0x3f);
305 alrm
->time
.tm_year
= -1;
307 alrm
->enabled
= !!(alarmvals
[0] & M41T80_ALMON_AFE
);
308 alrm
->pending
= (flags
& M41T80_FLAGS_AF
) && alrm
->enabled
;
313 static struct rtc_class_ops m41t80_rtc_ops
= {
314 .read_time
= m41t80_rtc_read_time
,
315 .set_time
= m41t80_rtc_set_time
,
316 .proc
= m41t80_rtc_proc
,
319 static ssize_t
flags_show(struct device
*dev
,
320 struct device_attribute
*attr
, char *buf
)
322 struct i2c_client
*client
= to_i2c_client(dev
);
325 val
= i2c_smbus_read_byte_data(client
, M41T80_REG_FLAGS
);
328 return sprintf(buf
, "%#x\n", val
);
330 static DEVICE_ATTR_RO(flags
);
332 static ssize_t
sqwfreq_show(struct device
*dev
,
333 struct device_attribute
*attr
, char *buf
)
335 struct i2c_client
*client
= to_i2c_client(dev
);
336 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
339 if (!(clientdata
->features
& M41T80_FEATURE_SQ
))
342 reg_sqw
= M41T80_REG_SQW
;
343 if (clientdata
->features
& M41T80_FEATURE_SQ_ALT
)
344 reg_sqw
= M41T80_REG_WDAY
;
345 val
= i2c_smbus_read_byte_data(client
, reg_sqw
);
348 val
= (val
>> 4) & 0xf;
358 return sprintf(buf
, "%d\n", val
);
361 static ssize_t
sqwfreq_store(struct device
*dev
,
362 struct device_attribute
*attr
,
363 const char *buf
, size_t count
)
365 struct i2c_client
*client
= to_i2c_client(dev
);
366 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
367 int almon
, sqw
, reg_sqw
, rc
;
370 rc
= kstrtoul(buf
, 0, &val
);
374 if (!(clientdata
->features
& M41T80_FEATURE_SQ
))
378 if (!is_power_of_2(val
))
388 /* disable SQW, set SQW frequency & re-enable */
389 almon
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_MON
);
392 reg_sqw
= M41T80_REG_SQW
;
393 if (clientdata
->features
& M41T80_FEATURE_SQ_ALT
)
394 reg_sqw
= M41T80_REG_WDAY
;
395 sqw
= i2c_smbus_read_byte_data(client
, reg_sqw
);
398 sqw
= (sqw
& 0x0f) | (val
<< 4);
400 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
401 almon
& ~M41T80_ALMON_SQWE
);
406 rc
= i2c_smbus_write_byte_data(client
, reg_sqw
, sqw
);
410 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_MON
,
411 almon
| M41T80_ALMON_SQWE
);
417 static DEVICE_ATTR_RW(sqwfreq
);
419 static struct attribute
*attrs
[] = {
420 &dev_attr_flags
.attr
,
421 &dev_attr_sqwfreq
.attr
,
425 static struct attribute_group attr_group
= {
429 #ifdef CONFIG_RTC_DRV_M41T80_WDT
431 *****************************************************************************
435 *****************************************************************************
437 static struct i2c_client
*save_client
;
440 #define WD_TIMO 60 /* 1..31 seconds */
442 static int wdt_margin
= WD_TIMO
;
443 module_param(wdt_margin
, int, 0);
444 MODULE_PARM_DESC(wdt_margin
, "Watchdog timeout in seconds (default 60s)");
446 static unsigned long wdt_is_open
;
447 static int boot_flag
;
452 * Reload counter one with the watchdog timeout. We don't bother reloading
453 * the cascade counter.
455 static void wdt_ping(void)
457 unsigned char i2c_data
[2];
458 struct i2c_msg msgs1
[1] = {
460 .addr
= save_client
->addr
,
466 struct m41t80_data
*clientdata
= i2c_get_clientdata(save_client
);
468 i2c_data
[0] = 0x09; /* watchdog register */
471 i2c_data
[1] = (wdt_margin
& 0xFC) | 0x83; /* resolution = 4s */
474 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
476 i2c_data
[1] = wdt_margin
<< 2 | 0x82;
479 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
480 * that would be an invalid resolution.
482 if (clientdata
->features
& M41T80_FEATURE_WD
)
483 i2c_data
[1] &= ~M41T80_WATCHDOG_RB2
;
485 i2c_transfer(save_client
->adapter
, msgs1
, 1);
493 static void wdt_disable(void)
495 unsigned char i2c_data
[2], i2c_buf
[0x10];
496 struct i2c_msg msgs0
[2] = {
498 .addr
= save_client
->addr
,
504 .addr
= save_client
->addr
,
510 struct i2c_msg msgs1
[1] = {
512 .addr
= save_client
->addr
,
520 i2c_transfer(save_client
->adapter
, msgs0
, 2);
524 i2c_transfer(save_client
->adapter
, msgs1
, 1);
529 * @file: file handle to the watchdog
530 * @buf: buffer to write (unused as data does not matter here
531 * @count: count of bytes
532 * @ppos: pointer to the position to write. No seeks allowed
534 * A write to a watchdog device is defined as a keepalive signal. Any
535 * write of data will do, as we we don't define content meaning.
537 static ssize_t
wdt_write(struct file
*file
, const char __user
*buf
,
538 size_t count
, loff_t
*ppos
)
547 static ssize_t
wdt_read(struct file
*file
, char __user
*buf
,
548 size_t count
, loff_t
*ppos
)
555 * @inode: inode of the device
556 * @file: file handle to the device
557 * @cmd: watchdog command
558 * @arg: argument pointer
560 * The watchdog API defines a common set of functions for all watchdogs
561 * according to their available features. We only actually usefully support
562 * querying capabilities and current status.
564 static int wdt_ioctl(struct file
*file
, unsigned int cmd
,
568 static struct watchdog_info ident
= {
569 .options
= WDIOF_POWERUNDER
| WDIOF_KEEPALIVEPING
|
571 .firmware_version
= 1,
572 .identity
= "M41T80 WTD"
576 case WDIOC_GETSUPPORT
:
577 return copy_to_user((struct watchdog_info __user
*)arg
, &ident
,
578 sizeof(ident
)) ? -EFAULT
: 0;
580 case WDIOC_GETSTATUS
:
581 case WDIOC_GETBOOTSTATUS
:
582 return put_user(boot_flag
, (int __user
*)arg
);
583 case WDIOC_KEEPALIVE
:
586 case WDIOC_SETTIMEOUT
:
587 if (get_user(new_margin
, (int __user
*)arg
))
589 /* Arbitrary, can't find the card's limits */
590 if (new_margin
< 1 || new_margin
> 124)
592 wdt_margin
= new_margin
;
595 case WDIOC_GETTIMEOUT
:
596 return put_user(wdt_margin
, (int __user
*)arg
);
598 case WDIOC_SETOPTIONS
:
599 if (copy_from_user(&rv
, (int __user
*)arg
, sizeof(int)))
602 if (rv
& WDIOS_DISABLECARD
) {
603 pr_info("disable watchdog\n");
607 if (rv
& WDIOS_ENABLECARD
) {
608 pr_info("enable watchdog\n");
617 static long wdt_unlocked_ioctl(struct file
*file
, unsigned int cmd
,
622 mutex_lock(&m41t80_rtc_mutex
);
623 ret
= wdt_ioctl(file
, cmd
, arg
);
624 mutex_unlock(&m41t80_rtc_mutex
);
631 * @inode: inode of device
632 * @file: file handle to device
635 static int wdt_open(struct inode
*inode
, struct file
*file
)
637 if (MINOR(inode
->i_rdev
) == WATCHDOG_MINOR
) {
638 mutex_lock(&m41t80_rtc_mutex
);
639 if (test_and_set_bit(0, &wdt_is_open
)) {
640 mutex_unlock(&m41t80_rtc_mutex
);
647 mutex_unlock(&m41t80_rtc_mutex
);
648 return nonseekable_open(inode
, file
);
655 * @inode: inode to board
656 * @file: file handle to board
659 static int wdt_release(struct inode
*inode
, struct file
*file
)
661 if (MINOR(inode
->i_rdev
) == WATCHDOG_MINOR
)
662 clear_bit(0, &wdt_is_open
);
668 * @this: our notifier block
669 * @code: the event being reported
672 * Our notifier is called on system shutdowns. We want to turn the card
673 * off at reboot otherwise the machine will reboot again during memory
674 * test or worse yet during the following fsck. This would suck, in fact
675 * trust me - if it happens it does suck.
677 static int wdt_notify_sys(struct notifier_block
*this, unsigned long code
,
680 if (code
== SYS_DOWN
|| code
== SYS_HALT
)
681 /* Disable Watchdog */
686 static const struct file_operations wdt_fops
= {
687 .owner
= THIS_MODULE
,
689 .unlocked_ioctl
= wdt_unlocked_ioctl
,
692 .release
= wdt_release
,
696 static struct miscdevice wdt_dev
= {
697 .minor
= WATCHDOG_MINOR
,
703 * The WDT card needs to learn about soft shutdowns in order to
704 * turn the timebomb registers off.
706 static struct notifier_block wdt_notifier
= {
707 .notifier_call
= wdt_notify_sys
,
709 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
712 *****************************************************************************
716 *****************************************************************************
719 static void m41t80_remove_sysfs_group(void *_dev
)
721 struct device
*dev
= _dev
;
723 sysfs_remove_group(&dev
->kobj
, &attr_group
);
726 static int m41t80_probe(struct i2c_client
*client
,
727 const struct i2c_device_id
*id
)
729 struct i2c_adapter
*adapter
= to_i2c_adapter(client
->dev
.parent
);
731 struct rtc_device
*rtc
= NULL
;
733 struct m41t80_data
*m41t80_data
= NULL
;
735 if (!i2c_check_functionality(client
->adapter
, I2C_FUNC_SMBUS_I2C_BLOCK
|
736 I2C_FUNC_SMBUS_BYTE_DATA
)) {
737 dev_err(&adapter
->dev
, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
741 m41t80_data
= devm_kzalloc(&client
->dev
, sizeof(*m41t80_data
),
746 m41t80_data
->features
= id
->driver_data
;
747 i2c_set_clientdata(client
, m41t80_data
);
749 if (client
->irq
> 0) {
750 rc
= devm_request_threaded_irq(&client
->dev
, client
->irq
,
751 NULL
, m41t80_handle_irq
,
752 IRQF_TRIGGER_LOW
| IRQF_ONESHOT
,
755 dev_warn(&client
->dev
, "unable to request IRQ, alarms disabled\n");
758 m41t80_rtc_ops
.read_alarm
= m41t80_read_alarm
;
759 m41t80_rtc_ops
.set_alarm
= m41t80_set_alarm
;
760 m41t80_rtc_ops
.alarm_irq_enable
= m41t80_alarm_irq_enable
;
761 /* Enable the wakealarm */
762 device_init_wakeup(&client
->dev
, true);
766 rtc
= devm_rtc_device_register(&client
->dev
, client
->name
,
767 &m41t80_rtc_ops
, THIS_MODULE
);
771 m41t80_data
->rtc
= rtc
;
773 /* Make sure HT (Halt Update) bit is cleared */
774 rc
= i2c_smbus_read_byte_data(client
, M41T80_REG_ALARM_HOUR
);
776 if (rc
>= 0 && rc
& M41T80_ALHOUR_HT
) {
777 if (m41t80_data
->features
& M41T80_FEATURE_HT
) {
778 m41t80_get_datetime(client
, &tm
);
779 dev_info(&client
->dev
, "HT bit was set!\n");
780 dev_info(&client
->dev
,
781 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
783 tm
.tm_mon
+ 1, tm
.tm_mday
, tm
.tm_hour
,
784 tm
.tm_min
, tm
.tm_sec
);
786 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_ALARM_HOUR
,
787 rc
& ~M41T80_ALHOUR_HT
);
791 dev_err(&client
->dev
, "Can't clear HT bit\n");
795 /* Make sure ST (stop) bit is cleared */
796 rc
= i2c_smbus_read_byte_data(client
, M41T80_REG_SEC
);
798 if (rc
>= 0 && rc
& M41T80_SEC_ST
)
799 rc
= i2c_smbus_write_byte_data(client
, M41T80_REG_SEC
,
800 rc
& ~M41T80_SEC_ST
);
802 dev_err(&client
->dev
, "Can't clear ST bit\n");
806 /* Export sysfs entries */
807 rc
= sysfs_create_group(&(&client
->dev
)->kobj
, &attr_group
);
809 dev_err(&client
->dev
, "Failed to create sysfs group: %d\n", rc
);
813 rc
= devm_add_action(&client
->dev
, m41t80_remove_sysfs_group
,
816 m41t80_remove_sysfs_group(&client
->dev
);
817 dev_err(&client
->dev
,
818 "Failed to add sysfs cleanup action: %d\n", rc
);
822 #ifdef CONFIG_RTC_DRV_M41T80_WDT
823 if (m41t80_data
->features
& M41T80_FEATURE_HT
) {
824 save_client
= client
;
825 rc
= misc_register(&wdt_dev
);
828 rc
= register_reboot_notifier(&wdt_notifier
);
830 misc_deregister(&wdt_dev
);
838 static int m41t80_remove(struct i2c_client
*client
)
840 #ifdef CONFIG_RTC_DRV_M41T80_WDT
841 struct m41t80_data
*clientdata
= i2c_get_clientdata(client
);
843 if (clientdata
->features
& M41T80_FEATURE_HT
) {
844 misc_deregister(&wdt_dev
);
845 unregister_reboot_notifier(&wdt_notifier
);
852 static struct i2c_driver m41t80_driver
= {
854 .name
= "rtc-m41t80",
856 .probe
= m41t80_probe
,
857 .remove
= m41t80_remove
,
858 .id_table
= m41t80_id
,
861 module_i2c_driver(m41t80_driver
);
863 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
864 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
865 MODULE_LICENSE("GPL");