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1/*
2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
3 *
4 * Author: Alexander Bigga <ab@mycable.de>
5 *
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
7 *
8 * 2006 (c) mycable GmbH
9 *
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.
13 *
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
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
28#include <linux/fs.h>
29#include <linux/ioctl.h>
30#include <linux/miscdevice.h>
31#include <linux/reboot.h>
32#include <linux/watchdog.h>
33#endif
34
35#define M41T80_REG_SSEC 0
36#define M41T80_REG_SEC 1
37#define M41T80_REG_MIN 2
38#define M41T80_REG_HOUR 3
39#define M41T80_REG_WDAY 4
40#define M41T80_REG_DAY 5
41#define M41T80_REG_MON 6
42#define M41T80_REG_YEAR 7
43#define M41T80_REG_ALARM_MON 0xa
44#define M41T80_REG_ALARM_DAY 0xb
45#define M41T80_REG_ALARM_HOUR 0xc
46#define M41T80_REG_ALARM_MIN 0xd
47#define M41T80_REG_ALARM_SEC 0xe
48#define M41T80_REG_FLAGS 0xf
49#define M41T80_REG_SQW 0x13
50
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)
54
55#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
56#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
57#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
58#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
59#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
60#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
61#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
62#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
63#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
64
65#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
66#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
67#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
68#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
69#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
70
71static DEFINE_MUTEX(m41t80_rtc_mutex);
72static 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 },
84 { }
85};
86MODULE_DEVICE_TABLE(i2c, m41t80_id);
87
88struct m41t80_data {
89 u8 features;
90 struct rtc_device *rtc;
91};
92
93static int m41t80_get_datetime(struct i2c_client *client,
94 struct rtc_time *tm)
95{
96 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
97 struct i2c_msg msgs[] = {
98 {
99 .addr = client->addr,
100 .flags = 0,
101 .len = 1,
102 .buf = dt_addr,
103 },
104 {
105 .addr = client->addr,
106 .flags = I2C_M_RD,
107 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
108 .buf = buf + M41T80_REG_SEC,
109 },
110 };
111
112 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
113 dev_err(&client->dev, "read error\n");
114 return -EIO;
115 }
116
117 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
118 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
119 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
120 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
121 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
122 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
123
124 /* assume 20YY not 19YY, and ignore the Century Bit */
125 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
126 return rtc_valid_tm(tm);
127}
128
129/* Sets the given date and time to the real time clock. */
130static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
131{
132 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
133 u8 *buf = &wbuf[1];
134 u8 dt_addr[1] = { M41T80_REG_SEC };
135 struct i2c_msg msgs_in[] = {
136 {
137 .addr = client->addr,
138 .flags = 0,
139 .len = 1,
140 .buf = dt_addr,
141 },
142 {
143 .addr = client->addr,
144 .flags = I2C_M_RD,
145 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
146 .buf = buf + M41T80_REG_SEC,
147 },
148 };
149 struct i2c_msg msgs[] = {
150 {
151 .addr = client->addr,
152 .flags = 0,
153 .len = 1 + M41T80_DATETIME_REG_SIZE,
154 .buf = wbuf,
155 },
156 };
157
158 /* Read current reg values into buf[1..7] */
159 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
160 dev_err(&client->dev, "read error\n");
161 return -EIO;
162 }
163
164 wbuf[0] = 0; /* offset into rtc's regs */
165 /* Merge time-data and register flags into buf[0..7] */
166 buf[M41T80_REG_SSEC] = 0;
167 buf[M41T80_REG_SEC] =
168 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
169 buf[M41T80_REG_MIN] =
170 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
171 buf[M41T80_REG_HOUR] =
172 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f);
173 buf[M41T80_REG_WDAY] =
174 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
175 buf[M41T80_REG_DAY] =
176 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
177 buf[M41T80_REG_MON] =
178 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
179
180 /* assume 20YY not 19YY */
181 if (tm->tm_year < 100 || tm->tm_year > 199) {
182 dev_err(&client->dev, "Year must be between 2000 and 2099. It's %d.\n",
183 tm->tm_year + 1900);
184 return -EINVAL;
185 }
186 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
187
188 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
189 dev_err(&client->dev, "write error\n");
190 return -EIO;
191 }
192 return 0;
193}
194
195#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
196static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
197{
198 struct i2c_client *client = to_i2c_client(dev);
199 struct m41t80_data *clientdata = i2c_get_clientdata(client);
200 u8 reg;
201
202 if (clientdata->features & M41T80_FEATURE_BL) {
203 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
204 seq_printf(seq, "battery\t\t: %s\n",
205 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
206 }
207 return 0;
208}
209#else
210#define m41t80_rtc_proc NULL
211#endif
212
213static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
214{
215 return m41t80_get_datetime(to_i2c_client(dev), tm);
216}
217
218static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
219{
220 return m41t80_set_datetime(to_i2c_client(dev), tm);
221}
222
223/*
224 * XXX - m41t80 alarm functionality is reported broken.
225 * until it is fixed, don't register alarm functions.
226 */
227static struct rtc_class_ops m41t80_rtc_ops = {
228 .read_time = m41t80_rtc_read_time,
229 .set_time = m41t80_rtc_set_time,
230 .proc = m41t80_rtc_proc,
231};
232
233#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
234static ssize_t m41t80_sysfs_show_flags(struct device *dev,
235 struct device_attribute *attr, char *buf)
236{
237 struct i2c_client *client = to_i2c_client(dev);
238 int val;
239
240 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
241 if (val < 0)
242 return val;
243 return sprintf(buf, "%#x\n", val);
244}
245static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
246
247static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
248 struct device_attribute *attr, char *buf)
249{
250 struct i2c_client *client = to_i2c_client(dev);
251 struct m41t80_data *clientdata = i2c_get_clientdata(client);
252 int val, reg_sqw;
253
254 if (!(clientdata->features & M41T80_FEATURE_SQ))
255 return -EINVAL;
256
257 reg_sqw = M41T80_REG_SQW;
258 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
259 reg_sqw = M41T80_REG_WDAY;
260 val = i2c_smbus_read_byte_data(client, reg_sqw);
261 if (val < 0)
262 return val;
263 val = (val >> 4) & 0xf;
264 switch (val) {
265 case 0:
266 break;
267 case 1:
268 val = 32768;
269 break;
270 default:
271 val = 32768 >> val;
272 }
273 return sprintf(buf, "%d\n", val);
274}
275static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
276 struct device_attribute *attr,
277 const char *buf, size_t count)
278{
279 struct i2c_client *client = to_i2c_client(dev);
280 struct m41t80_data *clientdata = i2c_get_clientdata(client);
281 int almon, sqw, reg_sqw, rc;
282 int val = simple_strtoul(buf, NULL, 0);
283
284 if (!(clientdata->features & M41T80_FEATURE_SQ))
285 return -EINVAL;
286
287 if (val) {
288 if (!is_power_of_2(val))
289 return -EINVAL;
290 val = ilog2(val);
291 if (val == 15)
292 val = 1;
293 else if (val < 14)
294 val = 15 - val;
295 else
296 return -EINVAL;
297 }
298 /* disable SQW, set SQW frequency & re-enable */
299 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
300 if (almon < 0)
301 return almon;
302 reg_sqw = M41T80_REG_SQW;
303 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
304 reg_sqw = M41T80_REG_WDAY;
305 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
306 if (sqw < 0)
307 return sqw;
308 sqw = (sqw & 0x0f) | (val << 4);
309
310 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
311 almon & ~M41T80_ALMON_SQWE);
312 if (rc < 0)
313 return rc;
314
315 if (val) {
316 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
317 if (rc < 0)
318 return rc;
319
320 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
321 almon | M41T80_ALMON_SQWE);
322 if (rc <0)
323 return rc;
324 }
325 return count;
326}
327static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
328 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
329
330static struct attribute *attrs[] = {
331 &dev_attr_flags.attr,
332 &dev_attr_sqwfreq.attr,
333 NULL,
334};
335static struct attribute_group attr_group = {
336 .attrs = attrs,
337};
338
339static int m41t80_sysfs_register(struct device *dev)
340{
341 return sysfs_create_group(&dev->kobj, &attr_group);
342}
343#else
344static int m41t80_sysfs_register(struct device *dev)
345{
346 return 0;
347}
348#endif
349
350#ifdef CONFIG_RTC_DRV_M41T80_WDT
351/*
352 *****************************************************************************
353 *
354 * Watchdog Driver
355 *
356 *****************************************************************************
357 */
358static struct i2c_client *save_client;
359
360/* Default margin */
361#define WD_TIMO 60 /* 1..31 seconds */
362
363static int wdt_margin = WD_TIMO;
364module_param(wdt_margin, int, 0);
365MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
366
367static unsigned long wdt_is_open;
368static int boot_flag;
369
370/**
371 * wdt_ping:
372 *
373 * Reload counter one with the watchdog timeout. We don't bother reloading
374 * the cascade counter.
375 */
376static void wdt_ping(void)
377{
378 unsigned char i2c_data[2];
379 struct i2c_msg msgs1[1] = {
380 {
381 .addr = save_client->addr,
382 .flags = 0,
383 .len = 2,
384 .buf = i2c_data,
385 },
386 };
387 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
388
389 i2c_data[0] = 0x09; /* watchdog register */
390
391 if (wdt_margin > 31)
392 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
393 else
394 /*
395 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
396 */
397 i2c_data[1] = wdt_margin<<2 | 0x82;
398
399 /*
400 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
401 * that would be an invalid resolution.
402 */
403 if (clientdata->features & M41T80_FEATURE_WD)
404 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
405
406 i2c_transfer(save_client->adapter, msgs1, 1);
407}
408
409/**
410 * wdt_disable:
411 *
412 * disables watchdog.
413 */
414static void wdt_disable(void)
415{
416 unsigned char i2c_data[2], i2c_buf[0x10];
417 struct i2c_msg msgs0[2] = {
418 {
419 .addr = save_client->addr,
420 .flags = 0,
421 .len = 1,
422 .buf = i2c_data,
423 },
424 {
425 .addr = save_client->addr,
426 .flags = I2C_M_RD,
427 .len = 1,
428 .buf = i2c_buf,
429 },
430 };
431 struct i2c_msg msgs1[1] = {
432 {
433 .addr = save_client->addr,
434 .flags = 0,
435 .len = 2,
436 .buf = i2c_data,
437 },
438 };
439
440 i2c_data[0] = 0x09;
441 i2c_transfer(save_client->adapter, msgs0, 2);
442
443 i2c_data[0] = 0x09;
444 i2c_data[1] = 0x00;
445 i2c_transfer(save_client->adapter, msgs1, 1);
446}
447
448/**
449 * wdt_write:
450 * @file: file handle to the watchdog
451 * @buf: buffer to write (unused as data does not matter here
452 * @count: count of bytes
453 * @ppos: pointer to the position to write. No seeks allowed
454 *
455 * A write to a watchdog device is defined as a keepalive signal. Any
456 * write of data will do, as we we don't define content meaning.
457 */
458static ssize_t wdt_write(struct file *file, const char __user *buf,
459 size_t count, loff_t *ppos)
460{
461 if (count) {
462 wdt_ping();
463 return 1;
464 }
465 return 0;
466}
467
468static ssize_t wdt_read(struct file *file, char __user *buf,
469 size_t count, loff_t *ppos)
470{
471 return 0;
472}
473
474/**
475 * wdt_ioctl:
476 * @inode: inode of the device
477 * @file: file handle to the device
478 * @cmd: watchdog command
479 * @arg: argument pointer
480 *
481 * The watchdog API defines a common set of functions for all watchdogs
482 * according to their available features. We only actually usefully support
483 * querying capabilities and current status.
484 */
485static int wdt_ioctl(struct file *file, unsigned int cmd,
486 unsigned long arg)
487{
488 int new_margin, rv;
489 static struct watchdog_info ident = {
490 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
491 WDIOF_SETTIMEOUT,
492 .firmware_version = 1,
493 .identity = "M41T80 WTD"
494 };
495
496 switch (cmd) {
497 case WDIOC_GETSUPPORT:
498 return copy_to_user((struct watchdog_info __user *)arg, &ident,
499 sizeof(ident)) ? -EFAULT : 0;
500
501 case WDIOC_GETSTATUS:
502 case WDIOC_GETBOOTSTATUS:
503 return put_user(boot_flag, (int __user *)arg);
504 case WDIOC_KEEPALIVE:
505 wdt_ping();
506 return 0;
507 case WDIOC_SETTIMEOUT:
508 if (get_user(new_margin, (int __user *)arg))
509 return -EFAULT;
510 /* Arbitrary, can't find the card's limits */
511 if (new_margin < 1 || new_margin > 124)
512 return -EINVAL;
513 wdt_margin = new_margin;
514 wdt_ping();
515 /* Fall */
516 case WDIOC_GETTIMEOUT:
517 return put_user(wdt_margin, (int __user *)arg);
518
519 case WDIOC_SETOPTIONS:
520 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
521 return -EFAULT;
522
523 if (rv & WDIOS_DISABLECARD) {
524 pr_info("disable watchdog\n");
525 wdt_disable();
526 }
527
528 if (rv & WDIOS_ENABLECARD) {
529 pr_info("enable watchdog\n");
530 wdt_ping();
531 }
532
533 return -EINVAL;
534 }
535 return -ENOTTY;
536}
537
538static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
539 unsigned long arg)
540{
541 int ret;
542
543 mutex_lock(&m41t80_rtc_mutex);
544 ret = wdt_ioctl(file, cmd, arg);
545 mutex_unlock(&m41t80_rtc_mutex);
546
547 return ret;
548}
549
550/**
551 * wdt_open:
552 * @inode: inode of device
553 * @file: file handle to device
554 *
555 */
556static int wdt_open(struct inode *inode, struct file *file)
557{
558 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
559 mutex_lock(&m41t80_rtc_mutex);
560 if (test_and_set_bit(0, &wdt_is_open)) {
561 mutex_unlock(&m41t80_rtc_mutex);
562 return -EBUSY;
563 }
564 /*
565 * Activate
566 */
567 wdt_is_open = 1;
568 mutex_unlock(&m41t80_rtc_mutex);
569 return nonseekable_open(inode, file);
570 }
571 return -ENODEV;
572}
573
574/**
575 * wdt_close:
576 * @inode: inode to board
577 * @file: file handle to board
578 *
579 */
580static int wdt_release(struct inode *inode, struct file *file)
581{
582 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
583 clear_bit(0, &wdt_is_open);
584 return 0;
585}
586
587/**
588 * notify_sys:
589 * @this: our notifier block
590 * @code: the event being reported
591 * @unused: unused
592 *
593 * Our notifier is called on system shutdowns. We want to turn the card
594 * off at reboot otherwise the machine will reboot again during memory
595 * test or worse yet during the following fsck. This would suck, in fact
596 * trust me - if it happens it does suck.
597 */
598static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
599 void *unused)
600{
601 if (code == SYS_DOWN || code == SYS_HALT)
602 /* Disable Watchdog */
603 wdt_disable();
604 return NOTIFY_DONE;
605}
606
607static const struct file_operations wdt_fops = {
608 .owner = THIS_MODULE,
609 .read = wdt_read,
610 .unlocked_ioctl = wdt_unlocked_ioctl,
611 .write = wdt_write,
612 .open = wdt_open,
613 .release = wdt_release,
614 .llseek = no_llseek,
615};
616
617static struct miscdevice wdt_dev = {
618 .minor = WATCHDOG_MINOR,
619 .name = "watchdog",
620 .fops = &wdt_fops,
621};
622
623/*
624 * The WDT card needs to learn about soft shutdowns in order to
625 * turn the timebomb registers off.
626 */
627static struct notifier_block wdt_notifier = {
628 .notifier_call = wdt_notify_sys,
629};
630#endif /* CONFIG_RTC_DRV_M41T80_WDT */
631
632/*
633 *****************************************************************************
634 *
635 * Driver Interface
636 *
637 *****************************************************************************
638 */
639static int m41t80_probe(struct i2c_client *client,
640 const struct i2c_device_id *id)
641{
642 int rc = 0;
643 struct rtc_device *rtc = NULL;
644 struct rtc_time tm;
645 struct m41t80_data *clientdata = NULL;
646
647 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
648 | I2C_FUNC_SMBUS_BYTE_DATA))
649 return -ENODEV;
650
651 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
652 GFP_KERNEL);
653 if (!clientdata)
654 return -ENOMEM;
655
656 clientdata->features = id->driver_data;
657 i2c_set_clientdata(client, clientdata);
658
659 rtc = devm_rtc_device_register(&client->dev, client->name,
660 &m41t80_rtc_ops, THIS_MODULE);
661 if (IS_ERR(rtc))
662 return PTR_ERR(rtc);
663
664 clientdata->rtc = rtc;
665
666 /* Make sure HT (Halt Update) bit is cleared */
667 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
668
669 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
670 if (clientdata->features & M41T80_FEATURE_HT) {
671 m41t80_get_datetime(client, &tm);
672 dev_info(&client->dev, "HT bit was set!\n");
673 dev_info(&client->dev,
674 "Power Down at "
675 "%04i-%02i-%02i %02i:%02i:%02i\n",
676 tm.tm_year + 1900,
677 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
678 tm.tm_min, tm.tm_sec);
679 }
680 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
681 rc & ~M41T80_ALHOUR_HT);
682 }
683
684 if (rc < 0) {
685 dev_err(&client->dev, "Can't clear HT bit\n");
686 return rc;
687 }
688
689 /* Make sure ST (stop) bit is cleared */
690 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
691
692 if (rc >= 0 && rc & M41T80_SEC_ST)
693 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
694 rc & ~M41T80_SEC_ST);
695 if (rc < 0) {
696 dev_err(&client->dev, "Can't clear ST bit\n");
697 return rc;
698 }
699
700 rc = m41t80_sysfs_register(&client->dev);
701 if (rc)
702 return rc;
703
704#ifdef CONFIG_RTC_DRV_M41T80_WDT
705 if (clientdata->features & M41T80_FEATURE_HT) {
706 save_client = client;
707 rc = misc_register(&wdt_dev);
708 if (rc)
709 return rc;
710 rc = register_reboot_notifier(&wdt_notifier);
711 if (rc) {
712 misc_deregister(&wdt_dev);
713 return rc;
714 }
715 }
716#endif
717 return 0;
718}
719
720static int m41t80_remove(struct i2c_client *client)
721{
722#ifdef CONFIG_RTC_DRV_M41T80_WDT
723 struct m41t80_data *clientdata = i2c_get_clientdata(client);
724
725 if (clientdata->features & M41T80_FEATURE_HT) {
726 misc_deregister(&wdt_dev);
727 unregister_reboot_notifier(&wdt_notifier);
728 }
729#endif
730
731 return 0;
732}
733
734static struct i2c_driver m41t80_driver = {
735 .driver = {
736 .name = "rtc-m41t80",
737 },
738 .probe = m41t80_probe,
739 .remove = m41t80_remove,
740 .id_table = m41t80_id,
741};
742
743module_i2c_driver(m41t80_driver);
744
745MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
746MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
747MODULE_LICENSE("GPL");
1/*
2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
3 *
4 * Author: Alexander Bigga <ab@mycable.de>
5 *
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
7 *
8 * 2006 (c) mycable GmbH
9 *
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.
13 *
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/bcd.h>
19#include <linux/clk-provider.h>
20#include <linux/i2c.h>
21#include <linux/init.h>
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/of_device.h>
25#include <linux/rtc.h>
26#include <linux/slab.h>
27#include <linux/mutex.h>
28#include <linux/string.h>
29#ifdef CONFIG_RTC_DRV_M41T80_WDT
30#include <linux/fs.h>
31#include <linux/ioctl.h>
32#include <linux/miscdevice.h>
33#include <linux/reboot.h>
34#include <linux/watchdog.h>
35#endif
36
37#define M41T80_REG_SSEC 0x00
38#define M41T80_REG_SEC 0x01
39#define M41T80_REG_MIN 0x02
40#define M41T80_REG_HOUR 0x03
41#define M41T80_REG_WDAY 0x04
42#define M41T80_REG_DAY 0x05
43#define M41T80_REG_MON 0x06
44#define M41T80_REG_YEAR 0x07
45#define M41T80_REG_ALARM_MON 0x0a
46#define M41T80_REG_ALARM_DAY 0x0b
47#define M41T80_REG_ALARM_HOUR 0x0c
48#define M41T80_REG_ALARM_MIN 0x0d
49#define M41T80_REG_ALARM_SEC 0x0e
50#define M41T80_REG_FLAGS 0x0f
51#define M41T80_REG_SQW 0x13
52
53#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
54#define M41T80_ALARM_REG_SIZE \
55 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
56
57#define M41T80_SQW_MAX_FREQ 32768
58
59#define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
60#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
61#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
62#define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
63#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
64#define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
65#define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
66#define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
67#define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
68#define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
69
70#define M41T80_FEATURE_HT BIT(0) /* Halt feature */
71#define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
72#define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
73#define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
74#define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
75
76static const struct i2c_device_id m41t80_id[] = {
77 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
78 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
79 { "m41t80", M41T80_FEATURE_SQ },
80 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
81 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
84 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
85 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
86 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
87 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
88 { }
89};
90MODULE_DEVICE_TABLE(i2c, m41t80_id);
91
92static const struct of_device_id m41t80_of_match[] = {
93 {
94 .compatible = "st,m41t62",
95 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT)
96 },
97 {
98 .compatible = "st,m41t65",
99 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD)
100 },
101 {
102 .compatible = "st,m41t80",
103 .data = (void *)(M41T80_FEATURE_SQ)
104 },
105 {
106 .compatible = "st,m41t81",
107 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ)
108 },
109 {
110 .compatible = "st,m41t81s",
111 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
112 },
113 {
114 .compatible = "st,m41t82",
115 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
116 },
117 {
118 .compatible = "st,m41t83",
119 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
120 },
121 {
122 .compatible = "st,m41t84",
123 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
124 },
125 {
126 .compatible = "st,m41t85",
127 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
128 },
129 {
130 .compatible = "st,m41t87",
131 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
132 },
133 {
134 .compatible = "microcrystal,rv4162",
135 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
136 },
137 /* DT compatibility only, do not use compatibles below: */
138 {
139 .compatible = "st,rv4162",
140 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
141 },
142 {
143 .compatible = "rv4162",
144 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
145 },
146 { }
147};
148MODULE_DEVICE_TABLE(of, m41t80_of_match);
149
150struct m41t80_data {
151 unsigned long features;
152 struct i2c_client *client;
153 struct rtc_device *rtc;
154#ifdef CONFIG_COMMON_CLK
155 struct clk_hw sqw;
156 unsigned long freq;
157 unsigned int sqwe;
158#endif
159};
160
161static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
162{
163 struct i2c_client *client = dev_id;
164 struct m41t80_data *m41t80 = i2c_get_clientdata(client);
165 struct mutex *lock = &m41t80->rtc->ops_lock;
166 unsigned long events = 0;
167 int flags, flags_afe;
168
169 mutex_lock(lock);
170
171 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
172 if (flags_afe < 0) {
173 mutex_unlock(lock);
174 return IRQ_NONE;
175 }
176
177 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
178 if (flags <= 0) {
179 mutex_unlock(lock);
180 return IRQ_NONE;
181 }
182
183 if (flags & M41T80_FLAGS_AF) {
184 flags &= ~M41T80_FLAGS_AF;
185 flags_afe &= ~M41T80_ALMON_AFE;
186 events |= RTC_AF;
187 }
188
189 if (events) {
190 rtc_update_irq(m41t80->rtc, 1, events);
191 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
192 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
193 flags_afe);
194 }
195
196 mutex_unlock(lock);
197
198 return IRQ_HANDLED;
199}
200
201static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
202{
203 struct i2c_client *client = to_i2c_client(dev);
204 unsigned char buf[8];
205 int err, flags;
206
207 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
208 if (flags < 0)
209 return flags;
210
211 if (flags & M41T80_FLAGS_OF) {
212 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
213 return -EINVAL;
214 }
215
216 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
217 sizeof(buf), buf);
218 if (err < 0) {
219 dev_err(&client->dev, "Unable to read date\n");
220 return -EIO;
221 }
222
223 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
224 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
225 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
226 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
227 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
228 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
229
230 /* assume 20YY not 19YY, and ignore the Century Bit */
231 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
232 return 0;
233}
234
235static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
236{
237 struct i2c_client *client = to_i2c_client(dev);
238 struct m41t80_data *clientdata = i2c_get_clientdata(client);
239 unsigned char buf[8];
240 int err, flags;
241
242 if (tm->tm_year < 100 || tm->tm_year > 199)
243 return -EINVAL;
244
245 buf[M41T80_REG_SSEC] = 0;
246 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
247 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
248 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
249 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
250 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
251 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
252 buf[M41T80_REG_WDAY] = tm->tm_wday;
253
254 /* If the square wave output is controlled in the weekday register */
255 if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
256 int val;
257
258 val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
259 if (val < 0)
260 return val;
261
262 buf[M41T80_REG_WDAY] |= (val & 0xf0);
263 }
264
265 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
266 sizeof(buf), buf);
267 if (err < 0) {
268 dev_err(&client->dev, "Unable to write to date registers\n");
269 return err;
270 }
271
272 /* Clear the OF bit of Flags Register */
273 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
274 if (flags < 0)
275 return flags;
276
277 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
278 flags & ~M41T80_FLAGS_OF)) {
279 dev_err(&client->dev, "Unable to write flags register\n");
280 return -EIO;
281 }
282
283 return err;
284}
285
286static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
287{
288 struct i2c_client *client = to_i2c_client(dev);
289 struct m41t80_data *clientdata = i2c_get_clientdata(client);
290 u8 reg;
291
292 if (clientdata->features & M41T80_FEATURE_BL) {
293 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
294 seq_printf(seq, "battery\t\t: %s\n",
295 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
296 }
297 return 0;
298}
299
300static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
301{
302 struct i2c_client *client = to_i2c_client(dev);
303 int flags, retval;
304
305 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
306 if (flags < 0)
307 return flags;
308
309 if (enabled)
310 flags |= M41T80_ALMON_AFE;
311 else
312 flags &= ~M41T80_ALMON_AFE;
313
314 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
315 if (retval < 0) {
316 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
317 return retval;
318 }
319 return 0;
320}
321
322static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
323{
324 struct i2c_client *client = to_i2c_client(dev);
325 u8 alarmvals[5];
326 int ret, err;
327
328 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
329 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
330 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
331 alarmvals[3] = bin2bcd(alrm->time.tm_min);
332 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
333
334 /* Clear AF and AFE flags */
335 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
336 if (ret < 0)
337 return ret;
338 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
339 ret & ~(M41T80_ALMON_AFE));
340 if (err < 0) {
341 dev_err(dev, "Unable to clear AFE bit\n");
342 return err;
343 }
344
345 /* Keep SQWE bit value */
346 alarmvals[0] |= (ret & M41T80_ALMON_SQWE);
347
348 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
349 if (ret < 0)
350 return ret;
351
352 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
353 ret & ~(M41T80_FLAGS_AF));
354 if (err < 0) {
355 dev_err(dev, "Unable to clear AF bit\n");
356 return err;
357 }
358
359 /* Write the alarm */
360 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
361 5, alarmvals);
362 if (err)
363 return err;
364
365 /* Enable the alarm interrupt */
366 if (alrm->enabled) {
367 alarmvals[0] |= M41T80_ALMON_AFE;
368 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
369 alarmvals[0]);
370 if (err)
371 return err;
372 }
373
374 return 0;
375}
376
377static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
378{
379 struct i2c_client *client = to_i2c_client(dev);
380 u8 alarmvals[5];
381 int flags, ret;
382
383 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
384 5, alarmvals);
385 if (ret != 5)
386 return ret < 0 ? ret : -EIO;
387
388 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
389 if (flags < 0)
390 return flags;
391
392 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
393 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
394 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
395 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
396 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f);
397
398 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
399 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
400
401 return 0;
402}
403
404static struct rtc_class_ops m41t80_rtc_ops = {
405 .read_time = m41t80_rtc_read_time,
406 .set_time = m41t80_rtc_set_time,
407 .proc = m41t80_rtc_proc,
408};
409
410#ifdef CONFIG_PM_SLEEP
411static int m41t80_suspend(struct device *dev)
412{
413 struct i2c_client *client = to_i2c_client(dev);
414
415 if (client->irq >= 0 && device_may_wakeup(dev))
416 enable_irq_wake(client->irq);
417
418 return 0;
419}
420
421static int m41t80_resume(struct device *dev)
422{
423 struct i2c_client *client = to_i2c_client(dev);
424
425 if (client->irq >= 0 && device_may_wakeup(dev))
426 disable_irq_wake(client->irq);
427
428 return 0;
429}
430#endif
431
432static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
433
434#ifdef CONFIG_COMMON_CLK
435#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
436
437static unsigned long m41t80_decode_freq(int setting)
438{
439 return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ :
440 M41T80_SQW_MAX_FREQ >> setting;
441}
442
443static unsigned long m41t80_get_freq(struct m41t80_data *m41t80)
444{
445 struct i2c_client *client = m41t80->client;
446 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
447 M41T80_REG_WDAY : M41T80_REG_SQW;
448 int ret = i2c_smbus_read_byte_data(client, reg_sqw);
449
450 if (ret < 0)
451 return 0;
452 return m41t80_decode_freq(ret >> 4);
453}
454
455static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
456 unsigned long parent_rate)
457{
458 return sqw_to_m41t80_data(hw)->freq;
459}
460
461static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
462 unsigned long *prate)
463{
464 if (rate >= M41T80_SQW_MAX_FREQ)
465 return M41T80_SQW_MAX_FREQ;
466 if (rate >= M41T80_SQW_MAX_FREQ / 4)
467 return M41T80_SQW_MAX_FREQ / 4;
468 if (!rate)
469 return 0;
470 return 1 << ilog2(rate);
471}
472
473static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
474 unsigned long parent_rate)
475{
476 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
477 struct i2c_client *client = m41t80->client;
478 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
479 M41T80_REG_WDAY : M41T80_REG_SQW;
480 int reg, ret, val = 0;
481
482 if (rate >= M41T80_SQW_MAX_FREQ)
483 val = 1;
484 else if (rate >= M41T80_SQW_MAX_FREQ / 4)
485 val = 2;
486 else if (rate)
487 val = 15 - ilog2(rate);
488
489 reg = i2c_smbus_read_byte_data(client, reg_sqw);
490 if (reg < 0)
491 return reg;
492
493 reg = (reg & 0x0f) | (val << 4);
494
495 ret = i2c_smbus_write_byte_data(client, reg_sqw, reg);
496 if (!ret)
497 m41t80->freq = m41t80_decode_freq(val);
498 return ret;
499}
500
501static int m41t80_sqw_control(struct clk_hw *hw, bool enable)
502{
503 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
504 struct i2c_client *client = m41t80->client;
505 int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
506
507 if (ret < 0)
508 return ret;
509
510 if (enable)
511 ret |= M41T80_ALMON_SQWE;
512 else
513 ret &= ~M41T80_ALMON_SQWE;
514
515 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
516 if (!ret)
517 m41t80->sqwe = enable;
518 return ret;
519}
520
521static int m41t80_sqw_prepare(struct clk_hw *hw)
522{
523 return m41t80_sqw_control(hw, 1);
524}
525
526static void m41t80_sqw_unprepare(struct clk_hw *hw)
527{
528 m41t80_sqw_control(hw, 0);
529}
530
531static int m41t80_sqw_is_prepared(struct clk_hw *hw)
532{
533 return sqw_to_m41t80_data(hw)->sqwe;
534}
535
536static const struct clk_ops m41t80_sqw_ops = {
537 .prepare = m41t80_sqw_prepare,
538 .unprepare = m41t80_sqw_unprepare,
539 .is_prepared = m41t80_sqw_is_prepared,
540 .recalc_rate = m41t80_sqw_recalc_rate,
541 .round_rate = m41t80_sqw_round_rate,
542 .set_rate = m41t80_sqw_set_rate,
543};
544
545static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
546{
547 struct i2c_client *client = m41t80->client;
548 struct device_node *node = client->dev.of_node;
549 struct clk *clk;
550 struct clk_init_data init;
551 int ret;
552
553 /* First disable the clock */
554 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
555 if (ret < 0)
556 return ERR_PTR(ret);
557 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
558 ret & ~(M41T80_ALMON_SQWE));
559 if (ret < 0)
560 return ERR_PTR(ret);
561
562 init.name = "m41t80-sqw";
563 init.ops = &m41t80_sqw_ops;
564 init.flags = 0;
565 init.parent_names = NULL;
566 init.num_parents = 0;
567 m41t80->sqw.init = &init;
568 m41t80->freq = m41t80_get_freq(m41t80);
569
570 /* optional override of the clockname */
571 of_property_read_string(node, "clock-output-names", &init.name);
572
573 /* register the clock */
574 clk = clk_register(&client->dev, &m41t80->sqw);
575 if (!IS_ERR(clk))
576 of_clk_add_provider(node, of_clk_src_simple_get, clk);
577
578 return clk;
579}
580#endif
581
582#ifdef CONFIG_RTC_DRV_M41T80_WDT
583/*
584 *****************************************************************************
585 *
586 * Watchdog Driver
587 *
588 *****************************************************************************
589 */
590static DEFINE_MUTEX(m41t80_rtc_mutex);
591static struct i2c_client *save_client;
592
593/* Default margin */
594#define WD_TIMO 60 /* 1..31 seconds */
595
596static int wdt_margin = WD_TIMO;
597module_param(wdt_margin, int, 0);
598MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
599
600static unsigned long wdt_is_open;
601static int boot_flag;
602
603/**
604 * wdt_ping:
605 *
606 * Reload counter one with the watchdog timeout. We don't bother reloading
607 * the cascade counter.
608 */
609static void wdt_ping(void)
610{
611 unsigned char i2c_data[2];
612 struct i2c_msg msgs1[1] = {
613 {
614 .addr = save_client->addr,
615 .flags = 0,
616 .len = 2,
617 .buf = i2c_data,
618 },
619 };
620 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
621
622 i2c_data[0] = 0x09; /* watchdog register */
623
624 if (wdt_margin > 31)
625 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
626 else
627 /*
628 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
629 */
630 i2c_data[1] = wdt_margin << 2 | 0x82;
631
632 /*
633 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
634 * that would be an invalid resolution.
635 */
636 if (clientdata->features & M41T80_FEATURE_WD)
637 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
638
639 i2c_transfer(save_client->adapter, msgs1, 1);
640}
641
642/**
643 * wdt_disable:
644 *
645 * disables watchdog.
646 */
647static void wdt_disable(void)
648{
649 unsigned char i2c_data[2], i2c_buf[0x10];
650 struct i2c_msg msgs0[2] = {
651 {
652 .addr = save_client->addr,
653 .flags = 0,
654 .len = 1,
655 .buf = i2c_data,
656 },
657 {
658 .addr = save_client->addr,
659 .flags = I2C_M_RD,
660 .len = 1,
661 .buf = i2c_buf,
662 },
663 };
664 struct i2c_msg msgs1[1] = {
665 {
666 .addr = save_client->addr,
667 .flags = 0,
668 .len = 2,
669 .buf = i2c_data,
670 },
671 };
672
673 i2c_data[0] = 0x09;
674 i2c_transfer(save_client->adapter, msgs0, 2);
675
676 i2c_data[0] = 0x09;
677 i2c_data[1] = 0x00;
678 i2c_transfer(save_client->adapter, msgs1, 1);
679}
680
681/**
682 * wdt_write:
683 * @file: file handle to the watchdog
684 * @buf: buffer to write (unused as data does not matter here
685 * @count: count of bytes
686 * @ppos: pointer to the position to write. No seeks allowed
687 *
688 * A write to a watchdog device is defined as a keepalive signal. Any
689 * write of data will do, as we we don't define content meaning.
690 */
691static ssize_t wdt_write(struct file *file, const char __user *buf,
692 size_t count, loff_t *ppos)
693{
694 if (count) {
695 wdt_ping();
696 return 1;
697 }
698 return 0;
699}
700
701static ssize_t wdt_read(struct file *file, char __user *buf,
702 size_t count, loff_t *ppos)
703{
704 return 0;
705}
706
707/**
708 * wdt_ioctl:
709 * @inode: inode of the device
710 * @file: file handle to the device
711 * @cmd: watchdog command
712 * @arg: argument pointer
713 *
714 * The watchdog API defines a common set of functions for all watchdogs
715 * according to their available features. We only actually usefully support
716 * querying capabilities and current status.
717 */
718static int wdt_ioctl(struct file *file, unsigned int cmd,
719 unsigned long arg)
720{
721 int new_margin, rv;
722 static struct watchdog_info ident = {
723 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
724 WDIOF_SETTIMEOUT,
725 .firmware_version = 1,
726 .identity = "M41T80 WTD"
727 };
728
729 switch (cmd) {
730 case WDIOC_GETSUPPORT:
731 return copy_to_user((struct watchdog_info __user *)arg, &ident,
732 sizeof(ident)) ? -EFAULT : 0;
733
734 case WDIOC_GETSTATUS:
735 case WDIOC_GETBOOTSTATUS:
736 return put_user(boot_flag, (int __user *)arg);
737 case WDIOC_KEEPALIVE:
738 wdt_ping();
739 return 0;
740 case WDIOC_SETTIMEOUT:
741 if (get_user(new_margin, (int __user *)arg))
742 return -EFAULT;
743 /* Arbitrary, can't find the card's limits */
744 if (new_margin < 1 || new_margin > 124)
745 return -EINVAL;
746 wdt_margin = new_margin;
747 wdt_ping();
748 /* Fall */
749 case WDIOC_GETTIMEOUT:
750 return put_user(wdt_margin, (int __user *)arg);
751
752 case WDIOC_SETOPTIONS:
753 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
754 return -EFAULT;
755
756 if (rv & WDIOS_DISABLECARD) {
757 pr_info("disable watchdog\n");
758 wdt_disable();
759 }
760
761 if (rv & WDIOS_ENABLECARD) {
762 pr_info("enable watchdog\n");
763 wdt_ping();
764 }
765
766 return -EINVAL;
767 }
768 return -ENOTTY;
769}
770
771static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
772 unsigned long arg)
773{
774 int ret;
775
776 mutex_lock(&m41t80_rtc_mutex);
777 ret = wdt_ioctl(file, cmd, arg);
778 mutex_unlock(&m41t80_rtc_mutex);
779
780 return ret;
781}
782
783/**
784 * wdt_open:
785 * @inode: inode of device
786 * @file: file handle to device
787 *
788 */
789static int wdt_open(struct inode *inode, struct file *file)
790{
791 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
792 mutex_lock(&m41t80_rtc_mutex);
793 if (test_and_set_bit(0, &wdt_is_open)) {
794 mutex_unlock(&m41t80_rtc_mutex);
795 return -EBUSY;
796 }
797 /*
798 * Activate
799 */
800 wdt_is_open = 1;
801 mutex_unlock(&m41t80_rtc_mutex);
802 return nonseekable_open(inode, file);
803 }
804 return -ENODEV;
805}
806
807/**
808 * wdt_close:
809 * @inode: inode to board
810 * @file: file handle to board
811 *
812 */
813static int wdt_release(struct inode *inode, struct file *file)
814{
815 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
816 clear_bit(0, &wdt_is_open);
817 return 0;
818}
819
820/**
821 * notify_sys:
822 * @this: our notifier block
823 * @code: the event being reported
824 * @unused: unused
825 *
826 * Our notifier is called on system shutdowns. We want to turn the card
827 * off at reboot otherwise the machine will reboot again during memory
828 * test or worse yet during the following fsck. This would suck, in fact
829 * trust me - if it happens it does suck.
830 */
831static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
832 void *unused)
833{
834 if (code == SYS_DOWN || code == SYS_HALT)
835 /* Disable Watchdog */
836 wdt_disable();
837 return NOTIFY_DONE;
838}
839
840static const struct file_operations wdt_fops = {
841 .owner = THIS_MODULE,
842 .read = wdt_read,
843 .unlocked_ioctl = wdt_unlocked_ioctl,
844 .write = wdt_write,
845 .open = wdt_open,
846 .release = wdt_release,
847 .llseek = no_llseek,
848};
849
850static struct miscdevice wdt_dev = {
851 .minor = WATCHDOG_MINOR,
852 .name = "watchdog",
853 .fops = &wdt_fops,
854};
855
856/*
857 * The WDT card needs to learn about soft shutdowns in order to
858 * turn the timebomb registers off.
859 */
860static struct notifier_block wdt_notifier = {
861 .notifier_call = wdt_notify_sys,
862};
863#endif /* CONFIG_RTC_DRV_M41T80_WDT */
864
865/*
866 *****************************************************************************
867 *
868 * Driver Interface
869 *
870 *****************************************************************************
871 */
872
873static int m41t80_probe(struct i2c_client *client,
874 const struct i2c_device_id *id)
875{
876 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
877 int rc = 0;
878 struct rtc_time tm;
879 struct m41t80_data *m41t80_data = NULL;
880 bool wakeup_source = false;
881
882 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
883 I2C_FUNC_SMBUS_BYTE_DATA)) {
884 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
885 return -ENODEV;
886 }
887
888 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
889 GFP_KERNEL);
890 if (!m41t80_data)
891 return -ENOMEM;
892
893 m41t80_data->client = client;
894 if (client->dev.of_node)
895 m41t80_data->features = (unsigned long)
896 of_device_get_match_data(&client->dev);
897 else
898 m41t80_data->features = id->driver_data;
899 i2c_set_clientdata(client, m41t80_data);
900
901 m41t80_data->rtc = devm_rtc_allocate_device(&client->dev);
902 if (IS_ERR(m41t80_data->rtc))
903 return PTR_ERR(m41t80_data->rtc);
904
905#ifdef CONFIG_OF
906 wakeup_source = of_property_read_bool(client->dev.of_node,
907 "wakeup-source");
908#endif
909 if (client->irq > 0) {
910 rc = devm_request_threaded_irq(&client->dev, client->irq,
911 NULL, m41t80_handle_irq,
912 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
913 "m41t80", client);
914 if (rc) {
915 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
916 client->irq = 0;
917 wakeup_source = false;
918 }
919 }
920 if (client->irq > 0 || wakeup_source) {
921 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
922 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
923 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
924 /* Enable the wakealarm */
925 device_init_wakeup(&client->dev, true);
926 }
927
928 m41t80_data->rtc->ops = &m41t80_rtc_ops;
929
930 if (client->irq <= 0) {
931 /* We cannot support UIE mode if we do not have an IRQ line */
932 m41t80_data->rtc->uie_unsupported = 1;
933 }
934
935 /* Make sure HT (Halt Update) bit is cleared */
936 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
937
938 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
939 if (m41t80_data->features & M41T80_FEATURE_HT) {
940 m41t80_rtc_read_time(&client->dev, &tm);
941 dev_info(&client->dev, "HT bit was set!\n");
942 dev_info(&client->dev,
943 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
944 tm.tm_year + 1900,
945 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
946 tm.tm_min, tm.tm_sec);
947 }
948 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
949 rc & ~M41T80_ALHOUR_HT);
950 }
951
952 if (rc < 0) {
953 dev_err(&client->dev, "Can't clear HT bit\n");
954 return rc;
955 }
956
957 /* Make sure ST (stop) bit is cleared */
958 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
959
960 if (rc >= 0 && rc & M41T80_SEC_ST)
961 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
962 rc & ~M41T80_SEC_ST);
963 if (rc < 0) {
964 dev_err(&client->dev, "Can't clear ST bit\n");
965 return rc;
966 }
967
968#ifdef CONFIG_RTC_DRV_M41T80_WDT
969 if (m41t80_data->features & M41T80_FEATURE_HT) {
970 save_client = client;
971 rc = misc_register(&wdt_dev);
972 if (rc)
973 return rc;
974 rc = register_reboot_notifier(&wdt_notifier);
975 if (rc) {
976 misc_deregister(&wdt_dev);
977 return rc;
978 }
979 }
980#endif
981#ifdef CONFIG_COMMON_CLK
982 if (m41t80_data->features & M41T80_FEATURE_SQ)
983 m41t80_sqw_register_clk(m41t80_data);
984#endif
985
986 rc = rtc_register_device(m41t80_data->rtc);
987 if (rc)
988 return rc;
989
990 return 0;
991}
992
993static int m41t80_remove(struct i2c_client *client)
994{
995#ifdef CONFIG_RTC_DRV_M41T80_WDT
996 struct m41t80_data *clientdata = i2c_get_clientdata(client);
997
998 if (clientdata->features & M41T80_FEATURE_HT) {
999 misc_deregister(&wdt_dev);
1000 unregister_reboot_notifier(&wdt_notifier);
1001 }
1002#endif
1003
1004 return 0;
1005}
1006
1007static struct i2c_driver m41t80_driver = {
1008 .driver = {
1009 .name = "rtc-m41t80",
1010 .of_match_table = of_match_ptr(m41t80_of_match),
1011 .pm = &m41t80_pm,
1012 },
1013 .probe = m41t80_probe,
1014 .remove = m41t80_remove,
1015 .id_table = m41t80_id,
1016};
1017
1018module_i2c_driver(m41t80_driver);
1019
1020MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
1021MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
1022MODULE_LICENSE("GPL");