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/of_device.h>
24 #include <linux/rtc.h>
25 #include <linux/slab.h>
26 #include <linux/mutex.h>
27 #include <linux/string.h>
28 #ifdef CONFIG_RTC_DRV_M41T80_WDT
30 #include <linux/ioctl.h>
31 #include <linux/miscdevice.h>
32 #include <linux/reboot.h>
33 #include <linux/watchdog.h>
36 #define M41T80_REG_SSEC 0x00
37 #define M41T80_REG_SEC 0x01
38 #define M41T80_REG_MIN 0x02
39 #define M41T80_REG_HOUR 0x03
40 #define M41T80_REG_WDAY 0x04
41 #define M41T80_REG_DAY 0x05
42 #define M41T80_REG_MON 0x06
43 #define M41T80_REG_YEAR 0x07
44 #define M41T80_REG_ALARM_MON 0x0a
45 #define M41T80_REG_ALARM_DAY 0x0b
46 #define M41T80_REG_ALARM_HOUR 0x0c
47 #define M41T80_REG_ALARM_MIN 0x0d
48 #define M41T80_REG_ALARM_SEC 0x0e
49 #define M41T80_REG_FLAGS 0x0f
50 #define M41T80_REG_SQW 0x13
52 #define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
53 #define M41T80_ALARM_REG_SIZE \
54 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
56 #define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
57 #define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
58 #define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
59 #define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
60 #define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
61 #define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
62 #define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
63 #define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
64 #define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
65 #define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
67 #define M41T80_FEATURE_HT BIT(0) /* Halt feature */
68 #define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
69 #define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
70 #define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
71 #define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
73 static DEFINE_MUTEX(m41t80_rtc_mutex);
74 static const struct i2c_device_id m41t80_id[] = {
75 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
76 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
77 { "m41t80", M41T80_FEATURE_SQ },
78 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
79 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
84 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
85 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
88 MODULE_DEVICE_TABLE(i2c, m41t80_id);
90 static const struct of_device_id m41t80_of_match[] = {
92 .compatible = "st,m41t62",
93 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT)
96 .compatible = "st,m41t65",
97 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD)
100 .compatible = "st,m41t80",
101 .data = (void *)(M41T80_FEATURE_SQ)
104 .compatible = "st,m41t81",
105 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ)
108 .compatible = "st,m41t81s",
109 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
112 .compatible = "st,m41t82",
113 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
116 .compatible = "st,m41t83",
117 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
120 .compatible = "st,m41t84",
121 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
124 .compatible = "st,m41t85",
125 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
128 .compatible = "st,m41t87",
129 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
132 .compatible = "microcrystal,rv4162",
133 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
135 /* DT compatibility only, do not use compatibles below: */
137 .compatible = "st,rv4162",
138 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
141 .compatible = "rv4162",
142 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
146 MODULE_DEVICE_TABLE(of, m41t80_of_match);
149 unsigned long features;
150 struct rtc_device *rtc;
153 static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
155 struct i2c_client *client = dev_id;
156 struct m41t80_data *m41t80 = i2c_get_clientdata(client);
157 struct mutex *lock = &m41t80->rtc->ops_lock;
158 unsigned long events = 0;
159 int flags, flags_afe;
163 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
169 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
175 if (flags & M41T80_FLAGS_AF) {
176 flags &= ~M41T80_FLAGS_AF;
177 flags_afe &= ~M41T80_ALMON_AFE;
182 rtc_update_irq(m41t80->rtc, 1, events);
183 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
184 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
193 static int m41t80_get_datetime(struct i2c_client *client,
196 unsigned char buf[8];
199 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
203 if (flags & M41T80_FLAGS_OF) {
204 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
208 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
211 dev_err(&client->dev, "Unable to read date\n");
215 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
216 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
217 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
218 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
219 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
220 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
222 /* assume 20YY not 19YY, and ignore the Century Bit */
223 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
224 return rtc_valid_tm(tm);
227 /* Sets the given date and time to the real time clock. */
228 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
230 unsigned char buf[8];
233 if (tm->tm_year < 100 || tm->tm_year > 199)
236 buf[M41T80_REG_SSEC] = 0;
237 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
238 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
239 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
240 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
241 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
242 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
243 buf[M41T80_REG_WDAY] = tm->tm_wday;
245 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
248 dev_err(&client->dev, "Unable to write to date registers\n");
252 /* Clear the OF bit of Flags Register */
253 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
257 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
258 flags & ~M41T80_FLAGS_OF)) {
259 dev_err(&client->dev, "Unable to write flags register\n");
266 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
268 struct i2c_client *client = to_i2c_client(dev);
269 struct m41t80_data *clientdata = i2c_get_clientdata(client);
272 if (clientdata->features & M41T80_FEATURE_BL) {
273 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
274 seq_printf(seq, "battery\t\t: %s\n",
275 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
280 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
282 return m41t80_get_datetime(to_i2c_client(dev), tm);
285 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
287 return m41t80_set_datetime(to_i2c_client(dev), tm);
290 static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
292 struct i2c_client *client = to_i2c_client(dev);
295 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
300 flags |= M41T80_ALMON_AFE;
302 flags &= ~M41T80_ALMON_AFE;
304 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
306 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
312 static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
314 struct i2c_client *client = to_i2c_client(dev);
318 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
319 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
320 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
321 alarmvals[3] = bin2bcd(alrm->time.tm_min);
322 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
324 /* Clear AF and AFE flags */
325 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
328 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
329 ret & ~(M41T80_ALMON_AFE));
331 dev_err(dev, "Unable to clear AFE bit\n");
335 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
339 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
340 ret & ~(M41T80_FLAGS_AF));
342 dev_err(dev, "Unable to clear AF bit\n");
346 /* Write the alarm */
347 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
352 /* Enable the alarm interrupt */
354 alarmvals[0] |= M41T80_ALMON_AFE;
355 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
364 static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
366 struct i2c_client *client = to_i2c_client(dev);
370 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
373 return ret < 0 ? ret : -EIO;
375 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
379 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
380 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
381 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
382 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
383 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f);
385 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
386 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
391 static struct rtc_class_ops m41t80_rtc_ops = {
392 .read_time = m41t80_rtc_read_time,
393 .set_time = m41t80_rtc_set_time,
394 .proc = m41t80_rtc_proc,
397 #ifdef CONFIG_PM_SLEEP
398 static int m41t80_suspend(struct device *dev)
400 struct i2c_client *client = to_i2c_client(dev);
402 if (client->irq >= 0 && device_may_wakeup(dev))
403 enable_irq_wake(client->irq);
408 static int m41t80_resume(struct device *dev)
410 struct i2c_client *client = to_i2c_client(dev);
412 if (client->irq >= 0 && device_may_wakeup(dev))
413 disable_irq_wake(client->irq);
419 static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
421 static ssize_t flags_show(struct device *dev,
422 struct device_attribute *attr, char *buf)
424 struct i2c_client *client = to_i2c_client(dev);
427 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
430 return sprintf(buf, "%#x\n", val);
432 static DEVICE_ATTR_RO(flags);
434 static ssize_t sqwfreq_show(struct device *dev,
435 struct device_attribute *attr, char *buf)
437 struct i2c_client *client = to_i2c_client(dev);
438 struct m41t80_data *clientdata = i2c_get_clientdata(client);
441 if (!(clientdata->features & M41T80_FEATURE_SQ))
444 reg_sqw = M41T80_REG_SQW;
445 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
446 reg_sqw = M41T80_REG_WDAY;
447 val = i2c_smbus_read_byte_data(client, reg_sqw);
450 val = (val >> 4) & 0xf;
460 return sprintf(buf, "%d\n", val);
463 static ssize_t sqwfreq_store(struct device *dev,
464 struct device_attribute *attr,
465 const char *buf, size_t count)
467 struct i2c_client *client = to_i2c_client(dev);
468 struct m41t80_data *clientdata = i2c_get_clientdata(client);
469 int almon, sqw, reg_sqw, rc;
472 rc = kstrtoul(buf, 0, &val);
476 if (!(clientdata->features & M41T80_FEATURE_SQ))
480 if (!is_power_of_2(val))
490 /* disable SQW, set SQW frequency & re-enable */
491 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
494 reg_sqw = M41T80_REG_SQW;
495 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
496 reg_sqw = M41T80_REG_WDAY;
497 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
500 sqw = (sqw & 0x0f) | (val << 4);
502 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
503 almon & ~M41T80_ALMON_SQWE);
508 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
512 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
513 almon | M41T80_ALMON_SQWE);
519 static DEVICE_ATTR_RW(sqwfreq);
521 static struct attribute *attrs[] = {
522 &dev_attr_flags.attr,
523 &dev_attr_sqwfreq.attr,
527 static struct attribute_group attr_group = {
531 #ifdef CONFIG_RTC_DRV_M41T80_WDT
533 *****************************************************************************
537 *****************************************************************************
539 static struct i2c_client *save_client;
542 #define WD_TIMO 60 /* 1..31 seconds */
544 static int wdt_margin = WD_TIMO;
545 module_param(wdt_margin, int, 0);
546 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
548 static unsigned long wdt_is_open;
549 static int boot_flag;
554 * Reload counter one with the watchdog timeout. We don't bother reloading
555 * the cascade counter.
557 static void wdt_ping(void)
559 unsigned char i2c_data[2];
560 struct i2c_msg msgs1[1] = {
562 .addr = save_client->addr,
568 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
570 i2c_data[0] = 0x09; /* watchdog register */
573 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
576 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
578 i2c_data[1] = wdt_margin << 2 | 0x82;
581 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
582 * that would be an invalid resolution.
584 if (clientdata->features & M41T80_FEATURE_WD)
585 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
587 i2c_transfer(save_client->adapter, msgs1, 1);
595 static void wdt_disable(void)
597 unsigned char i2c_data[2], i2c_buf[0x10];
598 struct i2c_msg msgs0[2] = {
600 .addr = save_client->addr,
606 .addr = save_client->addr,
612 struct i2c_msg msgs1[1] = {
614 .addr = save_client->addr,
622 i2c_transfer(save_client->adapter, msgs0, 2);
626 i2c_transfer(save_client->adapter, msgs1, 1);
631 * @file: file handle to the watchdog
632 * @buf: buffer to write (unused as data does not matter here
633 * @count: count of bytes
634 * @ppos: pointer to the position to write. No seeks allowed
636 * A write to a watchdog device is defined as a keepalive signal. Any
637 * write of data will do, as we we don't define content meaning.
639 static ssize_t wdt_write(struct file *file, const char __user *buf,
640 size_t count, loff_t *ppos)
649 static ssize_t wdt_read(struct file *file, char __user *buf,
650 size_t count, loff_t *ppos)
657 * @inode: inode of the device
658 * @file: file handle to the device
659 * @cmd: watchdog command
660 * @arg: argument pointer
662 * The watchdog API defines a common set of functions for all watchdogs
663 * according to their available features. We only actually usefully support
664 * querying capabilities and current status.
666 static int wdt_ioctl(struct file *file, unsigned int cmd,
670 static struct watchdog_info ident = {
671 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
673 .firmware_version = 1,
674 .identity = "M41T80 WTD"
678 case WDIOC_GETSUPPORT:
679 return copy_to_user((struct watchdog_info __user *)arg, &ident,
680 sizeof(ident)) ? -EFAULT : 0;
682 case WDIOC_GETSTATUS:
683 case WDIOC_GETBOOTSTATUS:
684 return put_user(boot_flag, (int __user *)arg);
685 case WDIOC_KEEPALIVE:
688 case WDIOC_SETTIMEOUT:
689 if (get_user(new_margin, (int __user *)arg))
691 /* Arbitrary, can't find the card's limits */
692 if (new_margin < 1 || new_margin > 124)
694 wdt_margin = new_margin;
697 case WDIOC_GETTIMEOUT:
698 return put_user(wdt_margin, (int __user *)arg);
700 case WDIOC_SETOPTIONS:
701 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
704 if (rv & WDIOS_DISABLECARD) {
705 pr_info("disable watchdog\n");
709 if (rv & WDIOS_ENABLECARD) {
710 pr_info("enable watchdog\n");
719 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
724 mutex_lock(&m41t80_rtc_mutex);
725 ret = wdt_ioctl(file, cmd, arg);
726 mutex_unlock(&m41t80_rtc_mutex);
733 * @inode: inode of device
734 * @file: file handle to device
737 static int wdt_open(struct inode *inode, struct file *file)
739 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
740 mutex_lock(&m41t80_rtc_mutex);
741 if (test_and_set_bit(0, &wdt_is_open)) {
742 mutex_unlock(&m41t80_rtc_mutex);
749 mutex_unlock(&m41t80_rtc_mutex);
750 return nonseekable_open(inode, file);
757 * @inode: inode to board
758 * @file: file handle to board
761 static int wdt_release(struct inode *inode, struct file *file)
763 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
764 clear_bit(0, &wdt_is_open);
770 * @this: our notifier block
771 * @code: the event being reported
774 * Our notifier is called on system shutdowns. We want to turn the card
775 * off at reboot otherwise the machine will reboot again during memory
776 * test or worse yet during the following fsck. This would suck, in fact
777 * trust me - if it happens it does suck.
779 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
782 if (code == SYS_DOWN || code == SYS_HALT)
783 /* Disable Watchdog */
788 static const struct file_operations wdt_fops = {
789 .owner = THIS_MODULE,
791 .unlocked_ioctl = wdt_unlocked_ioctl,
794 .release = wdt_release,
798 static struct miscdevice wdt_dev = {
799 .minor = WATCHDOG_MINOR,
805 * The WDT card needs to learn about soft shutdowns in order to
806 * turn the timebomb registers off.
808 static struct notifier_block wdt_notifier = {
809 .notifier_call = wdt_notify_sys,
811 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
814 *****************************************************************************
818 *****************************************************************************
821 static void m41t80_remove_sysfs_group(void *_dev)
823 struct device *dev = _dev;
825 sysfs_remove_group(&dev->kobj, &attr_group);
828 static int m41t80_probe(struct i2c_client *client,
829 const struct i2c_device_id *id)
831 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
833 struct rtc_device *rtc = NULL;
835 struct m41t80_data *m41t80_data = NULL;
837 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
838 I2C_FUNC_SMBUS_BYTE_DATA)) {
839 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
843 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
848 if (client->dev.of_node)
849 m41t80_data->features = (unsigned long)
850 of_device_get_match_data(&client->dev);
852 m41t80_data->features = id->driver_data;
853 i2c_set_clientdata(client, m41t80_data);
855 if (client->irq > 0) {
856 rc = devm_request_threaded_irq(&client->dev, client->irq,
857 NULL, m41t80_handle_irq,
858 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
861 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
864 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
865 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
866 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
867 /* Enable the wakealarm */
868 device_init_wakeup(&client->dev, true);
872 rtc = devm_rtc_device_register(&client->dev, client->name,
873 &m41t80_rtc_ops, THIS_MODULE);
877 m41t80_data->rtc = rtc;
879 /* Make sure HT (Halt Update) bit is cleared */
880 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
882 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
883 if (m41t80_data->features & M41T80_FEATURE_HT) {
884 m41t80_get_datetime(client, &tm);
885 dev_info(&client->dev, "HT bit was set!\n");
886 dev_info(&client->dev,
887 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
889 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
890 tm.tm_min, tm.tm_sec);
892 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
893 rc & ~M41T80_ALHOUR_HT);
897 dev_err(&client->dev, "Can't clear HT bit\n");
901 /* Make sure ST (stop) bit is cleared */
902 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
904 if (rc >= 0 && rc & M41T80_SEC_ST)
905 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
906 rc & ~M41T80_SEC_ST);
908 dev_err(&client->dev, "Can't clear ST bit\n");
912 /* Export sysfs entries */
913 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
915 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
919 rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group,
922 dev_err(&client->dev,
923 "Failed to add sysfs cleanup action: %d\n", rc);
927 #ifdef CONFIG_RTC_DRV_M41T80_WDT
928 if (m41t80_data->features & M41T80_FEATURE_HT) {
929 save_client = client;
930 rc = misc_register(&wdt_dev);
933 rc = register_reboot_notifier(&wdt_notifier);
935 misc_deregister(&wdt_dev);
943 static int m41t80_remove(struct i2c_client *client)
945 #ifdef CONFIG_RTC_DRV_M41T80_WDT
946 struct m41t80_data *clientdata = i2c_get_clientdata(client);
948 if (clientdata->features & M41T80_FEATURE_HT) {
949 misc_deregister(&wdt_dev);
950 unregister_reboot_notifier(&wdt_notifier);
957 static struct i2c_driver m41t80_driver = {
959 .name = "rtc-m41t80",
960 .of_match_table = of_match_ptr(m41t80_of_match),
963 .probe = m41t80_probe,
964 .remove = m41t80_remove,
965 .id_table = m41t80_id,
968 module_i2c_driver(m41t80_driver);
970 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
971 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
972 MODULE_LICENSE("GPL");