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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#include <linux/bcd.h>
17#include <linux/i2c.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/rtc.h>
22#include <linux/slab.h>
23#include <linux/mutex.h>
24#include <linux/string.h>
25#ifdef CONFIG_RTC_DRV_M41T80_WDT
26#include <linux/fs.h>
27#include <linux/ioctl.h>
28#include <linux/miscdevice.h>
29#include <linux/reboot.h>
30#include <linux/watchdog.h>
31#endif
32
33#define M41T80_REG_SSEC 0
34#define M41T80_REG_SEC 1
35#define M41T80_REG_MIN 2
36#define M41T80_REG_HOUR 3
37#define M41T80_REG_WDAY 4
38#define M41T80_REG_DAY 5
39#define M41T80_REG_MON 6
40#define M41T80_REG_YEAR 7
41#define M41T80_REG_ALARM_MON 0xa
42#define M41T80_REG_ALARM_DAY 0xb
43#define M41T80_REG_ALARM_HOUR 0xc
44#define M41T80_REG_ALARM_MIN 0xd
45#define M41T80_REG_ALARM_SEC 0xe
46#define M41T80_REG_FLAGS 0xf
47#define M41T80_REG_SQW 0x13
48
49#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
50#define M41T80_ALARM_REG_SIZE \
51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
52
53#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
54#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
55#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
56#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
57#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
58#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
59#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
60#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
61#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
62
63#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
64#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
65#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
66#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
67#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
68
69#define DRV_VERSION "0.05"
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 { }
84};
85MODULE_DEVICE_TABLE(i2c, m41t80_id);
86
87struct m41t80_data {
88 u8 features;
89 struct rtc_device *rtc;
90};
91
92static int m41t80_get_datetime(struct i2c_client *client,
93 struct rtc_time *tm)
94{
95 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
96 struct i2c_msg msgs[] = {
97 {
98 .addr = client->addr,
99 .flags = 0,
100 .len = 1,
101 .buf = dt_addr,
102 },
103 {
104 .addr = client->addr,
105 .flags = I2C_M_RD,
106 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
107 .buf = buf + M41T80_REG_SEC,
108 },
109 };
110
111 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
112 dev_err(&client->dev, "read error\n");
113 return -EIO;
114 }
115
116 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
117 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
118 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
119 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
120 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
121 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
122
123 /* assume 20YY not 19YY, and ignore the Century Bit */
124 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
125 return rtc_valid_tm(tm);
126}
127
128/* Sets the given date and time to the real time clock. */
129static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
130{
131 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
132 u8 *buf = &wbuf[1];
133 u8 dt_addr[1] = { M41T80_REG_SEC };
134 struct i2c_msg msgs_in[] = {
135 {
136 .addr = client->addr,
137 .flags = 0,
138 .len = 1,
139 .buf = dt_addr,
140 },
141 {
142 .addr = client->addr,
143 .flags = I2C_M_RD,
144 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
145 .buf = buf + M41T80_REG_SEC,
146 },
147 };
148 struct i2c_msg msgs[] = {
149 {
150 .addr = client->addr,
151 .flags = 0,
152 .len = 1 + M41T80_DATETIME_REG_SIZE,
153 .buf = wbuf,
154 },
155 };
156
157 /* Read current reg values into buf[1..7] */
158 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
159 dev_err(&client->dev, "read error\n");
160 return -EIO;
161 }
162
163 wbuf[0] = 0; /* offset into rtc's regs */
164 /* Merge time-data and register flags into buf[0..7] */
165 buf[M41T80_REG_SSEC] = 0;
166 buf[M41T80_REG_SEC] =
167 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
168 buf[M41T80_REG_MIN] =
169 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
170 buf[M41T80_REG_HOUR] =
171 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
172 buf[M41T80_REG_WDAY] =
173 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
174 buf[M41T80_REG_DAY] =
175 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
176 buf[M41T80_REG_MON] =
177 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
178 /* assume 20YY not 19YY */
179 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
180
181 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
182 dev_err(&client->dev, "write error\n");
183 return -EIO;
184 }
185 return 0;
186}
187
188#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
189static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
190{
191 struct i2c_client *client = to_i2c_client(dev);
192 struct m41t80_data *clientdata = i2c_get_clientdata(client);
193 u8 reg;
194
195 if (clientdata->features & M41T80_FEATURE_BL) {
196 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
197 seq_printf(seq, "battery\t\t: %s\n",
198 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
199 }
200 return 0;
201}
202#else
203#define m41t80_rtc_proc NULL
204#endif
205
206static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
207{
208 return m41t80_get_datetime(to_i2c_client(dev), tm);
209}
210
211static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
212{
213 return m41t80_set_datetime(to_i2c_client(dev), tm);
214}
215
216static int m41t80_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
217{
218 struct i2c_client *client = to_i2c_client(dev);
219 int rc;
220
221 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
222 if (rc < 0)
223 goto err;
224
225 if (enabled)
226 rc |= M41T80_ALMON_AFE;
227 else
228 rc &= ~M41T80_ALMON_AFE;
229
230 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
231 goto err;
232
233 return 0;
234err:
235 return -EIO;
236}
237
238static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
239{
240 struct i2c_client *client = to_i2c_client(dev);
241 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
242 u8 *buf = &wbuf[1];
243 u8 *reg = buf - M41T80_REG_ALARM_MON;
244 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
245 struct i2c_msg msgs_in[] = {
246 {
247 .addr = client->addr,
248 .flags = 0,
249 .len = 1,
250 .buf = dt_addr,
251 },
252 {
253 .addr = client->addr,
254 .flags = I2C_M_RD,
255 .len = M41T80_ALARM_REG_SIZE,
256 .buf = buf,
257 },
258 };
259 struct i2c_msg msgs[] = {
260 {
261 .addr = client->addr,
262 .flags = 0,
263 .len = 1 + M41T80_ALARM_REG_SIZE,
264 .buf = wbuf,
265 },
266 };
267
268 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
269 dev_err(&client->dev, "read error\n");
270 return -EIO;
271 }
272 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
273 reg[M41T80_REG_ALARM_DAY] = 0;
274 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
275 reg[M41T80_REG_ALARM_MIN] = 0;
276 reg[M41T80_REG_ALARM_SEC] = 0;
277
278 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
279 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
280 bin2bcd(t->time.tm_sec) : 0x80;
281 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
282 bin2bcd(t->time.tm_min) : 0x80;
283 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
284 bin2bcd(t->time.tm_hour) : 0x80;
285 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
286 bin2bcd(t->time.tm_mday) : 0x80;
287 if (t->time.tm_mon >= 0)
288 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
289 else
290 reg[M41T80_REG_ALARM_DAY] |= 0x40;
291
292 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
293 dev_err(&client->dev, "write error\n");
294 return -EIO;
295 }
296
297 if (t->enabled) {
298 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
299 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
300 reg[M41T80_REG_ALARM_MON]) < 0) {
301 dev_err(&client->dev, "write error\n");
302 return -EIO;
303 }
304 }
305 return 0;
306}
307
308static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
309{
310 struct i2c_client *client = to_i2c_client(dev);
311 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
312 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
313 u8 *reg = buf - M41T80_REG_ALARM_MON;
314 struct i2c_msg msgs[] = {
315 {
316 .addr = client->addr,
317 .flags = 0,
318 .len = 1,
319 .buf = dt_addr,
320 },
321 {
322 .addr = client->addr,
323 .flags = I2C_M_RD,
324 .len = M41T80_ALARM_REG_SIZE + 1,
325 .buf = buf,
326 },
327 };
328
329 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
330 dev_err(&client->dev, "read error\n");
331 return -EIO;
332 }
333 t->time.tm_sec = -1;
334 t->time.tm_min = -1;
335 t->time.tm_hour = -1;
336 t->time.tm_mday = -1;
337 t->time.tm_mon = -1;
338 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
339 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
340 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
341 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
342 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
343 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
344 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
345 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
346 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
347 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
348 t->time.tm_year = -1;
349 t->time.tm_wday = -1;
350 t->time.tm_yday = -1;
351 t->time.tm_isdst = -1;
352 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
353 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
354 return 0;
355}
356
357static struct rtc_class_ops m41t80_rtc_ops = {
358 .read_time = m41t80_rtc_read_time,
359 .set_time = m41t80_rtc_set_time,
360 .read_alarm = m41t80_rtc_read_alarm,
361 .set_alarm = m41t80_rtc_set_alarm,
362 .proc = m41t80_rtc_proc,
363 .alarm_irq_enable = m41t80_rtc_alarm_irq_enable,
364};
365
366#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
367static ssize_t m41t80_sysfs_show_flags(struct device *dev,
368 struct device_attribute *attr, char *buf)
369{
370 struct i2c_client *client = to_i2c_client(dev);
371 int val;
372
373 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
374 if (val < 0)
375 return -EIO;
376 return sprintf(buf, "%#x\n", val);
377}
378static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
379
380static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
381 struct device_attribute *attr, char *buf)
382{
383 struct i2c_client *client = to_i2c_client(dev);
384 struct m41t80_data *clientdata = i2c_get_clientdata(client);
385 int val, reg_sqw;
386
387 if (!(clientdata->features & M41T80_FEATURE_SQ))
388 return -EINVAL;
389
390 reg_sqw = M41T80_REG_SQW;
391 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
392 reg_sqw = M41T80_REG_WDAY;
393 val = i2c_smbus_read_byte_data(client, reg_sqw);
394 if (val < 0)
395 return -EIO;
396 val = (val >> 4) & 0xf;
397 switch (val) {
398 case 0:
399 break;
400 case 1:
401 val = 32768;
402 break;
403 default:
404 val = 32768 >> val;
405 }
406 return sprintf(buf, "%d\n", val);
407}
408static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
409 struct device_attribute *attr,
410 const char *buf, size_t count)
411{
412 struct i2c_client *client = to_i2c_client(dev);
413 struct m41t80_data *clientdata = i2c_get_clientdata(client);
414 int almon, sqw, reg_sqw;
415 int val = simple_strtoul(buf, NULL, 0);
416
417 if (!(clientdata->features & M41T80_FEATURE_SQ))
418 return -EINVAL;
419
420 if (val) {
421 if (!is_power_of_2(val))
422 return -EINVAL;
423 val = ilog2(val);
424 if (val == 15)
425 val = 1;
426 else if (val < 14)
427 val = 15 - val;
428 else
429 return -EINVAL;
430 }
431 /* disable SQW, set SQW frequency & re-enable */
432 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
433 if (almon < 0)
434 return -EIO;
435 reg_sqw = M41T80_REG_SQW;
436 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
437 reg_sqw = M41T80_REG_WDAY;
438 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
439 if (sqw < 0)
440 return -EIO;
441 sqw = (sqw & 0x0f) | (val << 4);
442 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
443 almon & ~M41T80_ALMON_SQWE) < 0 ||
444 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
445 return -EIO;
446 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
447 almon | M41T80_ALMON_SQWE) < 0)
448 return -EIO;
449 return count;
450}
451static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
452 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
453
454static struct attribute *attrs[] = {
455 &dev_attr_flags.attr,
456 &dev_attr_sqwfreq.attr,
457 NULL,
458};
459static struct attribute_group attr_group = {
460 .attrs = attrs,
461};
462
463static int m41t80_sysfs_register(struct device *dev)
464{
465 return sysfs_create_group(&dev->kobj, &attr_group);
466}
467#else
468static int m41t80_sysfs_register(struct device *dev)
469{
470 return 0;
471}
472#endif
473
474#ifdef CONFIG_RTC_DRV_M41T80_WDT
475/*
476 *****************************************************************************
477 *
478 * Watchdog Driver
479 *
480 *****************************************************************************
481 */
482static struct i2c_client *save_client;
483
484/* Default margin */
485#define WD_TIMO 60 /* 1..31 seconds */
486
487static int wdt_margin = WD_TIMO;
488module_param(wdt_margin, int, 0);
489MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
490
491static unsigned long wdt_is_open;
492static int boot_flag;
493
494/**
495 * wdt_ping:
496 *
497 * Reload counter one with the watchdog timeout. We don't bother reloading
498 * the cascade counter.
499 */
500static void wdt_ping(void)
501{
502 unsigned char i2c_data[2];
503 struct i2c_msg msgs1[1] = {
504 {
505 .addr = save_client->addr,
506 .flags = 0,
507 .len = 2,
508 .buf = i2c_data,
509 },
510 };
511 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
512
513 i2c_data[0] = 0x09; /* watchdog register */
514
515 if (wdt_margin > 31)
516 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
517 else
518 /*
519 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
520 */
521 i2c_data[1] = wdt_margin<<2 | 0x82;
522
523 /*
524 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
525 * that would be an invalid resolution.
526 */
527 if (clientdata->features & M41T80_FEATURE_WD)
528 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
529
530 i2c_transfer(save_client->adapter, msgs1, 1);
531}
532
533/**
534 * wdt_disable:
535 *
536 * disables watchdog.
537 */
538static void wdt_disable(void)
539{
540 unsigned char i2c_data[2], i2c_buf[0x10];
541 struct i2c_msg msgs0[2] = {
542 {
543 .addr = save_client->addr,
544 .flags = 0,
545 .len = 1,
546 .buf = i2c_data,
547 },
548 {
549 .addr = save_client->addr,
550 .flags = I2C_M_RD,
551 .len = 1,
552 .buf = i2c_buf,
553 },
554 };
555 struct i2c_msg msgs1[1] = {
556 {
557 .addr = save_client->addr,
558 .flags = 0,
559 .len = 2,
560 .buf = i2c_data,
561 },
562 };
563
564 i2c_data[0] = 0x09;
565 i2c_transfer(save_client->adapter, msgs0, 2);
566
567 i2c_data[0] = 0x09;
568 i2c_data[1] = 0x00;
569 i2c_transfer(save_client->adapter, msgs1, 1);
570}
571
572/**
573 * wdt_write:
574 * @file: file handle to the watchdog
575 * @buf: buffer to write (unused as data does not matter here
576 * @count: count of bytes
577 * @ppos: pointer to the position to write. No seeks allowed
578 *
579 * A write to a watchdog device is defined as a keepalive signal. Any
580 * write of data will do, as we we don't define content meaning.
581 */
582static ssize_t wdt_write(struct file *file, const char __user *buf,
583 size_t count, loff_t *ppos)
584{
585 if (count) {
586 wdt_ping();
587 return 1;
588 }
589 return 0;
590}
591
592static ssize_t wdt_read(struct file *file, char __user *buf,
593 size_t count, loff_t *ppos)
594{
595 return 0;
596}
597
598/**
599 * wdt_ioctl:
600 * @inode: inode of the device
601 * @file: file handle to the device
602 * @cmd: watchdog command
603 * @arg: argument pointer
604 *
605 * The watchdog API defines a common set of functions for all watchdogs
606 * according to their available features. We only actually usefully support
607 * querying capabilities and current status.
608 */
609static int wdt_ioctl(struct file *file, unsigned int cmd,
610 unsigned long arg)
611{
612 int new_margin, rv;
613 static struct watchdog_info ident = {
614 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
615 WDIOF_SETTIMEOUT,
616 .firmware_version = 1,
617 .identity = "M41T80 WTD"
618 };
619
620 switch (cmd) {
621 case WDIOC_GETSUPPORT:
622 return copy_to_user((struct watchdog_info __user *)arg, &ident,
623 sizeof(ident)) ? -EFAULT : 0;
624
625 case WDIOC_GETSTATUS:
626 case WDIOC_GETBOOTSTATUS:
627 return put_user(boot_flag, (int __user *)arg);
628 case WDIOC_KEEPALIVE:
629 wdt_ping();
630 return 0;
631 case WDIOC_SETTIMEOUT:
632 if (get_user(new_margin, (int __user *)arg))
633 return -EFAULT;
634 /* Arbitrary, can't find the card's limits */
635 if (new_margin < 1 || new_margin > 124)
636 return -EINVAL;
637 wdt_margin = new_margin;
638 wdt_ping();
639 /* Fall */
640 case WDIOC_GETTIMEOUT:
641 return put_user(wdt_margin, (int __user *)arg);
642
643 case WDIOC_SETOPTIONS:
644 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
645 return -EFAULT;
646
647 if (rv & WDIOS_DISABLECARD) {
648 pr_info("rtc-m41t80: disable watchdog\n");
649 wdt_disable();
650 }
651
652 if (rv & WDIOS_ENABLECARD) {
653 pr_info("rtc-m41t80: enable watchdog\n");
654 wdt_ping();
655 }
656
657 return -EINVAL;
658 }
659 return -ENOTTY;
660}
661
662static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
663 unsigned long arg)
664{
665 int ret;
666
667 mutex_lock(&m41t80_rtc_mutex);
668 ret = wdt_ioctl(file, cmd, arg);
669 mutex_unlock(&m41t80_rtc_mutex);
670
671 return ret;
672}
673
674/**
675 * wdt_open:
676 * @inode: inode of device
677 * @file: file handle to device
678 *
679 */
680static int wdt_open(struct inode *inode, struct file *file)
681{
682 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
683 mutex_lock(&m41t80_rtc_mutex);
684 if (test_and_set_bit(0, &wdt_is_open)) {
685 mutex_unlock(&m41t80_rtc_mutex);
686 return -EBUSY;
687 }
688 /*
689 * Activate
690 */
691 wdt_is_open = 1;
692 mutex_unlock(&m41t80_rtc_mutex);
693 return nonseekable_open(inode, file);
694 }
695 return -ENODEV;
696}
697
698/**
699 * wdt_close:
700 * @inode: inode to board
701 * @file: file handle to board
702 *
703 */
704static int wdt_release(struct inode *inode, struct file *file)
705{
706 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
707 clear_bit(0, &wdt_is_open);
708 return 0;
709}
710
711/**
712 * notify_sys:
713 * @this: our notifier block
714 * @code: the event being reported
715 * @unused: unused
716 *
717 * Our notifier is called on system shutdowns. We want to turn the card
718 * off at reboot otherwise the machine will reboot again during memory
719 * test or worse yet during the following fsck. This would suck, in fact
720 * trust me - if it happens it does suck.
721 */
722static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
723 void *unused)
724{
725 if (code == SYS_DOWN || code == SYS_HALT)
726 /* Disable Watchdog */
727 wdt_disable();
728 return NOTIFY_DONE;
729}
730
731static const struct file_operations wdt_fops = {
732 .owner = THIS_MODULE,
733 .read = wdt_read,
734 .unlocked_ioctl = wdt_unlocked_ioctl,
735 .write = wdt_write,
736 .open = wdt_open,
737 .release = wdt_release,
738 .llseek = no_llseek,
739};
740
741static struct miscdevice wdt_dev = {
742 .minor = WATCHDOG_MINOR,
743 .name = "watchdog",
744 .fops = &wdt_fops,
745};
746
747/*
748 * The WDT card needs to learn about soft shutdowns in order to
749 * turn the timebomb registers off.
750 */
751static struct notifier_block wdt_notifier = {
752 .notifier_call = wdt_notify_sys,
753};
754#endif /* CONFIG_RTC_DRV_M41T80_WDT */
755
756/*
757 *****************************************************************************
758 *
759 * Driver Interface
760 *
761 *****************************************************************************
762 */
763static int m41t80_probe(struct i2c_client *client,
764 const struct i2c_device_id *id)
765{
766 int rc = 0;
767 struct rtc_device *rtc = NULL;
768 struct rtc_time tm;
769 struct m41t80_data *clientdata = NULL;
770
771 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
772 | I2C_FUNC_SMBUS_BYTE_DATA)) {
773 rc = -ENODEV;
774 goto exit;
775 }
776
777 dev_info(&client->dev,
778 "chip found, driver version " DRV_VERSION "\n");
779
780 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
781 if (!clientdata) {
782 rc = -ENOMEM;
783 goto exit;
784 }
785
786 clientdata->features = id->driver_data;
787 i2c_set_clientdata(client, clientdata);
788
789 rtc = rtc_device_register(client->name, &client->dev,
790 &m41t80_rtc_ops, THIS_MODULE);
791 if (IS_ERR(rtc)) {
792 rc = PTR_ERR(rtc);
793 rtc = NULL;
794 goto exit;
795 }
796
797 clientdata->rtc = rtc;
798
799 /* Make sure HT (Halt Update) bit is cleared */
800 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
801 if (rc < 0)
802 goto ht_err;
803
804 if (rc & M41T80_ALHOUR_HT) {
805 if (clientdata->features & M41T80_FEATURE_HT) {
806 m41t80_get_datetime(client, &tm);
807 dev_info(&client->dev, "HT bit was set!\n");
808 dev_info(&client->dev,
809 "Power Down at "
810 "%04i-%02i-%02i %02i:%02i:%02i\n",
811 tm.tm_year + 1900,
812 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
813 tm.tm_min, tm.tm_sec);
814 }
815 if (i2c_smbus_write_byte_data(client,
816 M41T80_REG_ALARM_HOUR,
817 rc & ~M41T80_ALHOUR_HT) < 0)
818 goto ht_err;
819 }
820
821 /* Make sure ST (stop) bit is cleared */
822 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
823 if (rc < 0)
824 goto st_err;
825
826 if (rc & M41T80_SEC_ST) {
827 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
828 rc & ~M41T80_SEC_ST) < 0)
829 goto st_err;
830 }
831
832 rc = m41t80_sysfs_register(&client->dev);
833 if (rc)
834 goto exit;
835
836#ifdef CONFIG_RTC_DRV_M41T80_WDT
837 if (clientdata->features & M41T80_FEATURE_HT) {
838 save_client = client;
839 rc = misc_register(&wdt_dev);
840 if (rc)
841 goto exit;
842 rc = register_reboot_notifier(&wdt_notifier);
843 if (rc) {
844 misc_deregister(&wdt_dev);
845 goto exit;
846 }
847 }
848#endif
849 return 0;
850
851st_err:
852 rc = -EIO;
853 dev_err(&client->dev, "Can't clear ST bit\n");
854 goto exit;
855ht_err:
856 rc = -EIO;
857 dev_err(&client->dev, "Can't clear HT bit\n");
858 goto exit;
859
860exit:
861 if (rtc)
862 rtc_device_unregister(rtc);
863 kfree(clientdata);
864 return rc;
865}
866
867static int m41t80_remove(struct i2c_client *client)
868{
869 struct m41t80_data *clientdata = i2c_get_clientdata(client);
870 struct rtc_device *rtc = clientdata->rtc;
871
872#ifdef CONFIG_RTC_DRV_M41T80_WDT
873 if (clientdata->features & M41T80_FEATURE_HT) {
874 misc_deregister(&wdt_dev);
875 unregister_reboot_notifier(&wdt_notifier);
876 }
877#endif
878 if (rtc)
879 rtc_device_unregister(rtc);
880 kfree(clientdata);
881
882 return 0;
883}
884
885static struct i2c_driver m41t80_driver = {
886 .driver = {
887 .name = "rtc-m41t80",
888 },
889 .probe = m41t80_probe,
890 .remove = m41t80_remove,
891 .id_table = m41t80_id,
892};
893
894static int __init m41t80_rtc_init(void)
895{
896 return i2c_add_driver(&m41t80_driver);
897}
898
899static void __exit m41t80_rtc_exit(void)
900{
901 i2c_del_driver(&m41t80_driver);
902}
903
904MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
905MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
906MODULE_LICENSE("GPL");
907MODULE_VERSION(DRV_VERSION);
908
909module_init(m41t80_rtc_init);
910module_exit(m41t80_rtc_exit);
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 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
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 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 */
65
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 */
71
72static DEFINE_MUTEX(m41t80_rtc_mutex);
73static 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 },
85 { }
86};
87MODULE_DEVICE_TABLE(i2c, m41t80_id);
88
89struct m41t80_data {
90 u8 features;
91 struct rtc_device *rtc;
92};
93
94static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
95{
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;
101
102 mutex_lock(lock);
103
104 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
105 if (flags_afe < 0) {
106 mutex_unlock(lock);
107 return IRQ_NONE;
108 }
109
110 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
111 if (flags <= 0) {
112 mutex_unlock(lock);
113 return IRQ_NONE;
114 }
115
116 if (flags & M41T80_FLAGS_AF) {
117 flags &= ~M41T80_FLAGS_AF;
118 flags_afe &= ~M41T80_ALMON_AFE;
119 events |= RTC_AF;
120 }
121
122 if (events) {
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,
126 flags_afe);
127 }
128
129 mutex_unlock(lock);
130
131 return IRQ_HANDLED;
132}
133
134static int m41t80_get_datetime(struct i2c_client *client,
135 struct rtc_time *tm)
136{
137 unsigned char buf[8];
138 int err, flags;
139
140 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
141 if (flags < 0)
142 return flags;
143
144 if (flags & M41T80_FLAGS_OF) {
145 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
146 return -EINVAL;
147 }
148
149 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
150 sizeof(buf), buf);
151 if (err < 0) {
152 dev_err(&client->dev, "Unable to read date\n");
153 return -EIO;
154 }
155
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;
162
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);
166}
167
168/* Sets the given date and time to the real time clock. */
169static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
170{
171 unsigned char buf[8];
172 int err, flags;
173
174 if (tm->tm_year < 100 || tm->tm_year > 199)
175 return -EINVAL;
176
177 buf[M41T80_REG_SSEC] = 0;
178 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
179 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
180 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
181 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
182 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
183 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
184 buf[M41T80_REG_WDAY] = tm->tm_wday;
185
186 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
187 sizeof(buf), buf);
188 if (err < 0) {
189 dev_err(&client->dev, "Unable to write to date registers\n");
190 return err;
191 }
192
193 /* Clear the OF bit of Flags Register */
194 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
195 if (flags < 0)
196 return flags;
197
198 if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
199 flags & ~M41T80_FLAGS_OF)) {
200 dev_err(&client->dev, "Unable to write flags register\n");
201 return -EIO;
202 }
203
204 return err;
205}
206
207static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
208{
209 struct i2c_client *client = to_i2c_client(dev);
210 struct m41t80_data *clientdata = i2c_get_clientdata(client);
211 u8 reg;
212
213 if (clientdata->features & M41T80_FEATURE_BL) {
214 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
215 seq_printf(seq, "battery\t\t: %s\n",
216 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
217 }
218 return 0;
219}
220
221static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
222{
223 return m41t80_get_datetime(to_i2c_client(dev), tm);
224}
225
226static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
227{
228 return m41t80_set_datetime(to_i2c_client(dev), tm);
229}
230
231static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
232{
233 struct i2c_client *client = to_i2c_client(dev);
234 int flags, retval;
235
236 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
237 if (flags < 0)
238 return flags;
239
240 if (enabled)
241 flags |= M41T80_ALMON_AFE;
242 else
243 flags &= ~M41T80_ALMON_AFE;
244
245 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
246 if (retval < 0) {
247 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
248 return retval;
249 }
250 return 0;
251}
252
253static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
254{
255 struct i2c_client *client = to_i2c_client(dev);
256 u8 alarmvals[5];
257 int ret, err;
258
259 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
260 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
261 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
262 alarmvals[3] = bin2bcd(alrm->time.tm_min);
263 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
264
265 /* Clear AF and AFE flags */
266 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
267 if (ret < 0)
268 return ret;
269 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
270 ret & ~(M41T80_ALMON_AFE));
271 if (err < 0) {
272 dev_err(dev, "Unable to clear AFE bit\n");
273 return err;
274 }
275
276 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
277 if (ret < 0)
278 return ret;
279
280 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
281 ret & ~(M41T80_FLAGS_AF));
282 if (err < 0) {
283 dev_err(dev, "Unable to clear AF bit\n");
284 return err;
285 }
286
287 /* Write the alarm */
288 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
289 5, alarmvals);
290 if (err)
291 return err;
292
293 /* Enable the alarm interrupt */
294 if (alrm->enabled) {
295 alarmvals[0] |= M41T80_ALMON_AFE;
296 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
297 alarmvals[0]);
298 if (err)
299 return err;
300 }
301
302 return 0;
303}
304
305static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
306{
307 struct i2c_client *client = to_i2c_client(dev);
308 u8 alarmvals[5];
309 int flags, ret;
310
311 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
312 5, alarmvals);
313 if (ret != 5)
314 return ret < 0 ? ret : -EIO;
315
316 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
317 if (flags < 0)
318 return flags;
319
320 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
321 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
322 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
323 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
324 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f);
325
326 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
327 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
328
329 return 0;
330}
331
332static struct rtc_class_ops m41t80_rtc_ops = {
333 .read_time = m41t80_rtc_read_time,
334 .set_time = m41t80_rtc_set_time,
335 .proc = m41t80_rtc_proc,
336};
337
338#ifdef CONFIG_PM_SLEEP
339static int m41t80_suspend(struct device *dev)
340{
341 struct i2c_client *client = to_i2c_client(dev);
342
343 if (client->irq >= 0 && device_may_wakeup(dev))
344 enable_irq_wake(client->irq);
345
346 return 0;
347}
348
349static int m41t80_resume(struct device *dev)
350{
351 struct i2c_client *client = to_i2c_client(dev);
352
353 if (client->irq >= 0 && device_may_wakeup(dev))
354 disable_irq_wake(client->irq);
355
356 return 0;
357}
358#endif
359
360static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
361
362static ssize_t flags_show(struct device *dev,
363 struct device_attribute *attr, char *buf)
364{
365 struct i2c_client *client = to_i2c_client(dev);
366 int val;
367
368 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
369 if (val < 0)
370 return val;
371 return sprintf(buf, "%#x\n", val);
372}
373static DEVICE_ATTR_RO(flags);
374
375static ssize_t sqwfreq_show(struct device *dev,
376 struct device_attribute *attr, char *buf)
377{
378 struct i2c_client *client = to_i2c_client(dev);
379 struct m41t80_data *clientdata = i2c_get_clientdata(client);
380 int val, reg_sqw;
381
382 if (!(clientdata->features & M41T80_FEATURE_SQ))
383 return -EINVAL;
384
385 reg_sqw = M41T80_REG_SQW;
386 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
387 reg_sqw = M41T80_REG_WDAY;
388 val = i2c_smbus_read_byte_data(client, reg_sqw);
389 if (val < 0)
390 return val;
391 val = (val >> 4) & 0xf;
392 switch (val) {
393 case 0:
394 break;
395 case 1:
396 val = 32768;
397 break;
398 default:
399 val = 32768 >> val;
400 }
401 return sprintf(buf, "%d\n", val);
402}
403
404static ssize_t sqwfreq_store(struct device *dev,
405 struct device_attribute *attr,
406 const char *buf, size_t count)
407{
408 struct i2c_client *client = to_i2c_client(dev);
409 struct m41t80_data *clientdata = i2c_get_clientdata(client);
410 int almon, sqw, reg_sqw, rc;
411 unsigned long val;
412
413 rc = kstrtoul(buf, 0, &val);
414 if (rc < 0)
415 return rc;
416
417 if (!(clientdata->features & M41T80_FEATURE_SQ))
418 return -EINVAL;
419
420 if (val) {
421 if (!is_power_of_2(val))
422 return -EINVAL;
423 val = ilog2(val);
424 if (val == 15)
425 val = 1;
426 else if (val < 14)
427 val = 15 - val;
428 else
429 return -EINVAL;
430 }
431 /* disable SQW, set SQW frequency & re-enable */
432 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
433 if (almon < 0)
434 return almon;
435 reg_sqw = M41T80_REG_SQW;
436 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
437 reg_sqw = M41T80_REG_WDAY;
438 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
439 if (sqw < 0)
440 return sqw;
441 sqw = (sqw & 0x0f) | (val << 4);
442
443 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
444 almon & ~M41T80_ALMON_SQWE);
445 if (rc < 0)
446 return rc;
447
448 if (val) {
449 rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
450 if (rc < 0)
451 return rc;
452
453 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
454 almon | M41T80_ALMON_SQWE);
455 if (rc < 0)
456 return rc;
457 }
458 return count;
459}
460static DEVICE_ATTR_RW(sqwfreq);
461
462static struct attribute *attrs[] = {
463 &dev_attr_flags.attr,
464 &dev_attr_sqwfreq.attr,
465 NULL,
466};
467
468static struct attribute_group attr_group = {
469 .attrs = attrs,
470};
471
472#ifdef CONFIG_RTC_DRV_M41T80_WDT
473/*
474 *****************************************************************************
475 *
476 * Watchdog Driver
477 *
478 *****************************************************************************
479 */
480static struct i2c_client *save_client;
481
482/* Default margin */
483#define WD_TIMO 60 /* 1..31 seconds */
484
485static int wdt_margin = WD_TIMO;
486module_param(wdt_margin, int, 0);
487MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
488
489static unsigned long wdt_is_open;
490static int boot_flag;
491
492/**
493 * wdt_ping:
494 *
495 * Reload counter one with the watchdog timeout. We don't bother reloading
496 * the cascade counter.
497 */
498static void wdt_ping(void)
499{
500 unsigned char i2c_data[2];
501 struct i2c_msg msgs1[1] = {
502 {
503 .addr = save_client->addr,
504 .flags = 0,
505 .len = 2,
506 .buf = i2c_data,
507 },
508 };
509 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
510
511 i2c_data[0] = 0x09; /* watchdog register */
512
513 if (wdt_margin > 31)
514 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
515 else
516 /*
517 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
518 */
519 i2c_data[1] = wdt_margin << 2 | 0x82;
520
521 /*
522 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
523 * that would be an invalid resolution.
524 */
525 if (clientdata->features & M41T80_FEATURE_WD)
526 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
527
528 i2c_transfer(save_client->adapter, msgs1, 1);
529}
530
531/**
532 * wdt_disable:
533 *
534 * disables watchdog.
535 */
536static void wdt_disable(void)
537{
538 unsigned char i2c_data[2], i2c_buf[0x10];
539 struct i2c_msg msgs0[2] = {
540 {
541 .addr = save_client->addr,
542 .flags = 0,
543 .len = 1,
544 .buf = i2c_data,
545 },
546 {
547 .addr = save_client->addr,
548 .flags = I2C_M_RD,
549 .len = 1,
550 .buf = i2c_buf,
551 },
552 };
553 struct i2c_msg msgs1[1] = {
554 {
555 .addr = save_client->addr,
556 .flags = 0,
557 .len = 2,
558 .buf = i2c_data,
559 },
560 };
561
562 i2c_data[0] = 0x09;
563 i2c_transfer(save_client->adapter, msgs0, 2);
564
565 i2c_data[0] = 0x09;
566 i2c_data[1] = 0x00;
567 i2c_transfer(save_client->adapter, msgs1, 1);
568}
569
570/**
571 * wdt_write:
572 * @file: file handle to the watchdog
573 * @buf: buffer to write (unused as data does not matter here
574 * @count: count of bytes
575 * @ppos: pointer to the position to write. No seeks allowed
576 *
577 * A write to a watchdog device is defined as a keepalive signal. Any
578 * write of data will do, as we we don't define content meaning.
579 */
580static ssize_t wdt_write(struct file *file, const char __user *buf,
581 size_t count, loff_t *ppos)
582{
583 if (count) {
584 wdt_ping();
585 return 1;
586 }
587 return 0;
588}
589
590static ssize_t wdt_read(struct file *file, char __user *buf,
591 size_t count, loff_t *ppos)
592{
593 return 0;
594}
595
596/**
597 * wdt_ioctl:
598 * @inode: inode of the device
599 * @file: file handle to the device
600 * @cmd: watchdog command
601 * @arg: argument pointer
602 *
603 * The watchdog API defines a common set of functions for all watchdogs
604 * according to their available features. We only actually usefully support
605 * querying capabilities and current status.
606 */
607static int wdt_ioctl(struct file *file, unsigned int cmd,
608 unsigned long arg)
609{
610 int new_margin, rv;
611 static struct watchdog_info ident = {
612 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
613 WDIOF_SETTIMEOUT,
614 .firmware_version = 1,
615 .identity = "M41T80 WTD"
616 };
617
618 switch (cmd) {
619 case WDIOC_GETSUPPORT:
620 return copy_to_user((struct watchdog_info __user *)arg, &ident,
621 sizeof(ident)) ? -EFAULT : 0;
622
623 case WDIOC_GETSTATUS:
624 case WDIOC_GETBOOTSTATUS:
625 return put_user(boot_flag, (int __user *)arg);
626 case WDIOC_KEEPALIVE:
627 wdt_ping();
628 return 0;
629 case WDIOC_SETTIMEOUT:
630 if (get_user(new_margin, (int __user *)arg))
631 return -EFAULT;
632 /* Arbitrary, can't find the card's limits */
633 if (new_margin < 1 || new_margin > 124)
634 return -EINVAL;
635 wdt_margin = new_margin;
636 wdt_ping();
637 /* Fall */
638 case WDIOC_GETTIMEOUT:
639 return put_user(wdt_margin, (int __user *)arg);
640
641 case WDIOC_SETOPTIONS:
642 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
643 return -EFAULT;
644
645 if (rv & WDIOS_DISABLECARD) {
646 pr_info("disable watchdog\n");
647 wdt_disable();
648 }
649
650 if (rv & WDIOS_ENABLECARD) {
651 pr_info("enable watchdog\n");
652 wdt_ping();
653 }
654
655 return -EINVAL;
656 }
657 return -ENOTTY;
658}
659
660static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
661 unsigned long arg)
662{
663 int ret;
664
665 mutex_lock(&m41t80_rtc_mutex);
666 ret = wdt_ioctl(file, cmd, arg);
667 mutex_unlock(&m41t80_rtc_mutex);
668
669 return ret;
670}
671
672/**
673 * wdt_open:
674 * @inode: inode of device
675 * @file: file handle to device
676 *
677 */
678static int wdt_open(struct inode *inode, struct file *file)
679{
680 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
681 mutex_lock(&m41t80_rtc_mutex);
682 if (test_and_set_bit(0, &wdt_is_open)) {
683 mutex_unlock(&m41t80_rtc_mutex);
684 return -EBUSY;
685 }
686 /*
687 * Activate
688 */
689 wdt_is_open = 1;
690 mutex_unlock(&m41t80_rtc_mutex);
691 return nonseekable_open(inode, file);
692 }
693 return -ENODEV;
694}
695
696/**
697 * wdt_close:
698 * @inode: inode to board
699 * @file: file handle to board
700 *
701 */
702static int wdt_release(struct inode *inode, struct file *file)
703{
704 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
705 clear_bit(0, &wdt_is_open);
706 return 0;
707}
708
709/**
710 * notify_sys:
711 * @this: our notifier block
712 * @code: the event being reported
713 * @unused: unused
714 *
715 * Our notifier is called on system shutdowns. We want to turn the card
716 * off at reboot otherwise the machine will reboot again during memory
717 * test or worse yet during the following fsck. This would suck, in fact
718 * trust me - if it happens it does suck.
719 */
720static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
721 void *unused)
722{
723 if (code == SYS_DOWN || code == SYS_HALT)
724 /* Disable Watchdog */
725 wdt_disable();
726 return NOTIFY_DONE;
727}
728
729static const struct file_operations wdt_fops = {
730 .owner = THIS_MODULE,
731 .read = wdt_read,
732 .unlocked_ioctl = wdt_unlocked_ioctl,
733 .write = wdt_write,
734 .open = wdt_open,
735 .release = wdt_release,
736 .llseek = no_llseek,
737};
738
739static struct miscdevice wdt_dev = {
740 .minor = WATCHDOG_MINOR,
741 .name = "watchdog",
742 .fops = &wdt_fops,
743};
744
745/*
746 * The WDT card needs to learn about soft shutdowns in order to
747 * turn the timebomb registers off.
748 */
749static struct notifier_block wdt_notifier = {
750 .notifier_call = wdt_notify_sys,
751};
752#endif /* CONFIG_RTC_DRV_M41T80_WDT */
753
754/*
755 *****************************************************************************
756 *
757 * Driver Interface
758 *
759 *****************************************************************************
760 */
761
762static void m41t80_remove_sysfs_group(void *_dev)
763{
764 struct device *dev = _dev;
765
766 sysfs_remove_group(&dev->kobj, &attr_group);
767}
768
769static int m41t80_probe(struct i2c_client *client,
770 const struct i2c_device_id *id)
771{
772 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
773 int rc = 0;
774 struct rtc_device *rtc = NULL;
775 struct rtc_time tm;
776 struct m41t80_data *m41t80_data = NULL;
777
778 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
779 I2C_FUNC_SMBUS_BYTE_DATA)) {
780 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
781 return -ENODEV;
782 }
783
784 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
785 GFP_KERNEL);
786 if (!m41t80_data)
787 return -ENOMEM;
788
789 m41t80_data->features = id->driver_data;
790 i2c_set_clientdata(client, m41t80_data);
791
792 if (client->irq > 0) {
793 rc = devm_request_threaded_irq(&client->dev, client->irq,
794 NULL, m41t80_handle_irq,
795 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
796 "m41t80", client);
797 if (rc) {
798 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
799 client->irq = 0;
800 } else {
801 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
802 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
803 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
804 /* Enable the wakealarm */
805 device_init_wakeup(&client->dev, true);
806 }
807 }
808
809 rtc = devm_rtc_device_register(&client->dev, client->name,
810 &m41t80_rtc_ops, THIS_MODULE);
811 if (IS_ERR(rtc))
812 return PTR_ERR(rtc);
813
814 m41t80_data->rtc = rtc;
815
816 /* Make sure HT (Halt Update) bit is cleared */
817 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
818
819 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
820 if (m41t80_data->features & M41T80_FEATURE_HT) {
821 m41t80_get_datetime(client, &tm);
822 dev_info(&client->dev, "HT bit was set!\n");
823 dev_info(&client->dev,
824 "Power Down at %04i-%02i-%02i %02i:%02i:%02i\n",
825 tm.tm_year + 1900,
826 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
827 tm.tm_min, tm.tm_sec);
828 }
829 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
830 rc & ~M41T80_ALHOUR_HT);
831 }
832
833 if (rc < 0) {
834 dev_err(&client->dev, "Can't clear HT bit\n");
835 return rc;
836 }
837
838 /* Make sure ST (stop) bit is cleared */
839 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
840
841 if (rc >= 0 && rc & M41T80_SEC_ST)
842 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
843 rc & ~M41T80_SEC_ST);
844 if (rc < 0) {
845 dev_err(&client->dev, "Can't clear ST bit\n");
846 return rc;
847 }
848
849 /* Export sysfs entries */
850 rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
851 if (rc) {
852 dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
853 return rc;
854 }
855
856 rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group,
857 &client->dev);
858 if (rc) {
859 dev_err(&client->dev,
860 "Failed to add sysfs cleanup action: %d\n", rc);
861 return rc;
862 }
863
864#ifdef CONFIG_RTC_DRV_M41T80_WDT
865 if (m41t80_data->features & M41T80_FEATURE_HT) {
866 save_client = client;
867 rc = misc_register(&wdt_dev);
868 if (rc)
869 return rc;
870 rc = register_reboot_notifier(&wdt_notifier);
871 if (rc) {
872 misc_deregister(&wdt_dev);
873 return rc;
874 }
875 }
876#endif
877 return 0;
878}
879
880static int m41t80_remove(struct i2c_client *client)
881{
882#ifdef CONFIG_RTC_DRV_M41T80_WDT
883 struct m41t80_data *clientdata = i2c_get_clientdata(client);
884
885 if (clientdata->features & M41T80_FEATURE_HT) {
886 misc_deregister(&wdt_dev);
887 unregister_reboot_notifier(&wdt_notifier);
888 }
889#endif
890
891 return 0;
892}
893
894static struct i2c_driver m41t80_driver = {
895 .driver = {
896 .name = "rtc-m41t80",
897 .pm = &m41t80_pm,
898 },
899 .probe = m41t80_probe,
900 .remove = m41t80_remove,
901 .id_table = m41t80_id,
902};
903
904module_i2c_driver(m41t80_driver);
905
906MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
907MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
908MODULE_LICENSE("GPL");