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mm: add rss counters consistency check
[linux-2.6.git] / drivers / rtc / rtc-m41t80.c
blob64aedd8cc095810e4134ceb727538a24b2af6232
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
71 static DEFINE_MUTEX(m41t80_rtc_mutex);
72 static const struct i2c_device_id m41t80_id[] = {
73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
75 { "m41t80", M41T80_FEATURE_SQ },
76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { }
84 };
85 MODULE_DEVICE_TABLE(i2c, m41t80_id);
86
87 struct m41t80_data {
88 u8 features;
89 struct rtc_device *rtc;
90 };
91
92 static 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. */
129 static 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)
189 static 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
206 static 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
211 static 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
216 static 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;
234 err:
235 return -EIO;
236 }
237
238 static 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
308 static 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
357 static struct rtc_class_ops m41t80_rtc_ops = {
358 .read_time = m41t80_rtc_read_time,
359 .set_time = m41t80_rtc_set_time,
360 /*
361 * XXX - m41t80 alarm functionality is reported broken.
362 * until it is fixed, don't register alarm functions.
363 *
364 .read_alarm = m41t80_rtc_read_alarm,
365 .set_alarm = m41t80_rtc_set_alarm,
366 */
367 .proc = m41t80_rtc_proc,
368 /*
369 * See above comment on broken alarm
370 *
371 .alarm_irq_enable = m41t80_rtc_alarm_irq_enable,
372 */
373 };
374
375 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
376 static ssize_t m41t80_sysfs_show_flags(struct device *dev,
377 struct device_attribute *attr, char *buf)
378 {
379 struct i2c_client *client = to_i2c_client(dev);
380 int val;
381
382 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
383 if (val < 0)
384 return -EIO;
385 return sprintf(buf, "%#x\n", val);
386 }
387 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
388
389 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
390 struct device_attribute *attr, char *buf)
391 {
392 struct i2c_client *client = to_i2c_client(dev);
393 struct m41t80_data *clientdata = i2c_get_clientdata(client);
394 int val, reg_sqw;
395
396 if (!(clientdata->features & M41T80_FEATURE_SQ))
397 return -EINVAL;
398
399 reg_sqw = M41T80_REG_SQW;
400 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
401 reg_sqw = M41T80_REG_WDAY;
402 val = i2c_smbus_read_byte_data(client, reg_sqw);
403 if (val < 0)
404 return -EIO;
405 val = (val >> 4) & 0xf;
406 switch (val) {
407 case 0:
408 break;
409 case 1:
410 val = 32768;
411 break;
412 default:
413 val = 32768 >> val;
414 }
415 return sprintf(buf, "%d\n", val);
416 }
417 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
418 struct device_attribute *attr,
419 const char *buf, size_t count)
420 {
421 struct i2c_client *client = to_i2c_client(dev);
422 struct m41t80_data *clientdata = i2c_get_clientdata(client);
423 int almon, sqw, reg_sqw;
424 int val = simple_strtoul(buf, NULL, 0);
425
426 if (!(clientdata->features & M41T80_FEATURE_SQ))
427 return -EINVAL;
428
429 if (val) {
430 if (!is_power_of_2(val))
431 return -EINVAL;
432 val = ilog2(val);
433 if (val == 15)
434 val = 1;
435 else if (val < 14)
436 val = 15 - val;
437 else
438 return -EINVAL;
439 }
440 /* disable SQW, set SQW frequency & re-enable */
441 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
442 if (almon < 0)
443 return -EIO;
444 reg_sqw = M41T80_REG_SQW;
445 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
446 reg_sqw = M41T80_REG_WDAY;
447 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
448 if (sqw < 0)
449 return -EIO;
450 sqw = (sqw & 0x0f) | (val << 4);
451 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
452 almon & ~M41T80_ALMON_SQWE) < 0 ||
453 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
454 return -EIO;
455 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
456 almon | M41T80_ALMON_SQWE) < 0)
457 return -EIO;
458 return count;
459 }
460 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
461 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
462
463 static struct attribute *attrs[] = {
464 &dev_attr_flags.attr,
465 &dev_attr_sqwfreq.attr,
466 NULL,
467 };
468 static struct attribute_group attr_group = {
469 .attrs = attrs,
470 };
471
472 static int m41t80_sysfs_register(struct device *dev)
473 {
474 return sysfs_create_group(&dev->kobj, &attr_group);
475 }
476 #else
477 static int m41t80_sysfs_register(struct device *dev)
478 {
479 return 0;
480 }
481 #endif
482
483 #ifdef CONFIG_RTC_DRV_M41T80_WDT
484 /*
485 *****************************************************************************
486 *
487 * Watchdog Driver
488 *
489 *****************************************************************************
490 */
491 static struct i2c_client *save_client;
492
493 /* Default margin */
494 #define WD_TIMO 60 /* 1..31 seconds */
495
496 static int wdt_margin = WD_TIMO;
497 module_param(wdt_margin, int, 0);
498 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
499
500 static unsigned long wdt_is_open;
501 static int boot_flag;
502
503 /**
504 * wdt_ping:
505 *
506 * Reload counter one with the watchdog timeout. We don't bother reloading
507 * the cascade counter.
508 */
509 static void wdt_ping(void)
510 {
511 unsigned char i2c_data[2];
512 struct i2c_msg msgs1[1] = {
513 {
514 .addr = save_client->addr,
515 .flags = 0,
516 .len = 2,
517 .buf = i2c_data,
518 },
519 };
520 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
521
522 i2c_data[0] = 0x09; /* watchdog register */
523
524 if (wdt_margin > 31)
525 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
526 else
527 /*
528 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
529 */
530 i2c_data[1] = wdt_margin<<2 | 0x82;
531
532 /*
533 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
534 * that would be an invalid resolution.
535 */
536 if (clientdata->features & M41T80_FEATURE_WD)
537 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
538
539 i2c_transfer(save_client->adapter, msgs1, 1);
540 }
541
542 /**
543 * wdt_disable:
544 *
545 * disables watchdog.
546 */
547 static void wdt_disable(void)
548 {
549 unsigned char i2c_data[2], i2c_buf[0x10];
550 struct i2c_msg msgs0[2] = {
551 {
552 .addr = save_client->addr,
553 .flags = 0,
554 .len = 1,
555 .buf = i2c_data,
556 },
557 {
558 .addr = save_client->addr,
559 .flags = I2C_M_RD,
560 .len = 1,
561 .buf = i2c_buf,
562 },
563 };
564 struct i2c_msg msgs1[1] = {
565 {
566 .addr = save_client->addr,
567 .flags = 0,
568 .len = 2,
569 .buf = i2c_data,
570 },
571 };
572
573 i2c_data[0] = 0x09;
574 i2c_transfer(save_client->adapter, msgs0, 2);
575
576 i2c_data[0] = 0x09;
577 i2c_data[1] = 0x00;
578 i2c_transfer(save_client->adapter, msgs1, 1);
579 }
580
581 /**
582 * wdt_write:
583 * @file: file handle to the watchdog
584 * @buf: buffer to write (unused as data does not matter here
585 * @count: count of bytes
586 * @ppos: pointer to the position to write. No seeks allowed
587 *
588 * A write to a watchdog device is defined as a keepalive signal. Any
589 * write of data will do, as we we don't define content meaning.
590 */
591 static ssize_t wdt_write(struct file *file, const char __user *buf,
592 size_t count, loff_t *ppos)
593 {
594 if (count) {
595 wdt_ping();
596 return 1;
597 }
598 return 0;
599 }
600
601 static ssize_t wdt_read(struct file *file, char __user *buf,
602 size_t count, loff_t *ppos)
603 {
604 return 0;
605 }
606
607 /**
608 * wdt_ioctl:
609 * @inode: inode of the device
610 * @file: file handle to the device
611 * @cmd: watchdog command
612 * @arg: argument pointer
613 *
614 * The watchdog API defines a common set of functions for all watchdogs
615 * according to their available features. We only actually usefully support
616 * querying capabilities and current status.
617 */
618 static int wdt_ioctl(struct file *file, unsigned int cmd,
619 unsigned long arg)
620 {
621 int new_margin, rv;
622 static struct watchdog_info ident = {
623 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
624 WDIOF_SETTIMEOUT,
625 .firmware_version = 1,
626 .identity = "M41T80 WTD"
627 };
628
629 switch (cmd) {
630 case WDIOC_GETSUPPORT:
631 return copy_to_user((struct watchdog_info __user *)arg, &ident,
632 sizeof(ident)) ? -EFAULT : 0;
633
634 case WDIOC_GETSTATUS:
635 case WDIOC_GETBOOTSTATUS:
636 return put_user(boot_flag, (int __user *)arg);
637 case WDIOC_KEEPALIVE:
638 wdt_ping();
639 return 0;
640 case WDIOC_SETTIMEOUT:
641 if (get_user(new_margin, (int __user *)arg))
642 return -EFAULT;
643 /* Arbitrary, can't find the card's limits */
644 if (new_margin < 1 || new_margin > 124)
645 return -EINVAL;
646 wdt_margin = new_margin;
647 wdt_ping();
648 /* Fall */
649 case WDIOC_GETTIMEOUT:
650 return put_user(wdt_margin, (int __user *)arg);
651
652 case WDIOC_SETOPTIONS:
653 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
654 return -EFAULT;
655
656 if (rv & WDIOS_DISABLECARD) {
657 pr_info("rtc-m41t80: disable watchdog\n");
658 wdt_disable();
659 }
660
661 if (rv & WDIOS_ENABLECARD) {
662 pr_info("rtc-m41t80: enable watchdog\n");
663 wdt_ping();
664 }
665
666 return -EINVAL;
667 }
668 return -ENOTTY;
669 }
670
671 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
672 unsigned long arg)
673 {
674 int ret;
675
676 mutex_lock(&m41t80_rtc_mutex);
677 ret = wdt_ioctl(file, cmd, arg);
678 mutex_unlock(&m41t80_rtc_mutex);
679
680 return ret;
681 }
682
683 /**
684 * wdt_open:
685 * @inode: inode of device
686 * @file: file handle to device
687 *
688 */
689 static int wdt_open(struct inode *inode, struct file *file)
690 {
691 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
692 mutex_lock(&m41t80_rtc_mutex);
693 if (test_and_set_bit(0, &wdt_is_open)) {
694 mutex_unlock(&m41t80_rtc_mutex);
695 return -EBUSY;
696 }
697 /*
698 * Activate
699 */
700 wdt_is_open = 1;
701 mutex_unlock(&m41t80_rtc_mutex);
702 return nonseekable_open(inode, file);
703 }
704 return -ENODEV;
705 }
706
707 /**
708 * wdt_close:
709 * @inode: inode to board
710 * @file: file handle to board
711 *
712 */
713 static int wdt_release(struct inode *inode, struct file *file)
714 {
715 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
716 clear_bit(0, &wdt_is_open);
717 return 0;
718 }
719
720 /**
721 * notify_sys:
722 * @this: our notifier block
723 * @code: the event being reported
724 * @unused: unused
725 *
726 * Our notifier is called on system shutdowns. We want to turn the card
727 * off at reboot otherwise the machine will reboot again during memory
728 * test or worse yet during the following fsck. This would suck, in fact
729 * trust me - if it happens it does suck.
730 */
731 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
732 void *unused)
733 {
734 if (code == SYS_DOWN || code == SYS_HALT)
735 /* Disable Watchdog */
736 wdt_disable();
737 return NOTIFY_DONE;
738 }
739
740 static const struct file_operations wdt_fops = {
741 .owner = THIS_MODULE,
742 .read = wdt_read,
743 .unlocked_ioctl = wdt_unlocked_ioctl,
744 .write = wdt_write,
745 .open = wdt_open,
746 .release = wdt_release,
747 .llseek = no_llseek,
748 };
749
750 static struct miscdevice wdt_dev = {
751 .minor = WATCHDOG_MINOR,
752 .name = "watchdog",
753 .fops = &wdt_fops,
754 };
755
756 /*
757 * The WDT card needs to learn about soft shutdowns in order to
758 * turn the timebomb registers off.
759 */
760 static struct notifier_block wdt_notifier = {
761 .notifier_call = wdt_notify_sys,
762 };
763 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
764
765 /*
766 *****************************************************************************
767 *
768 * Driver Interface
769 *
770 *****************************************************************************
771 */
772 static int m41t80_probe(struct i2c_client *client,
773 const struct i2c_device_id *id)
774 {
775 int rc = 0;
776 struct rtc_device *rtc = NULL;
777 struct rtc_time tm;
778 struct m41t80_data *clientdata = NULL;
779
780 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
781 | I2C_FUNC_SMBUS_BYTE_DATA)) {
782 rc = -ENODEV;
783 goto exit;
784 }
785
786 dev_info(&client->dev,
787 "chip found, driver version " DRV_VERSION "\n");
788
789 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
790 if (!clientdata) {
791 rc = -ENOMEM;
792 goto exit;
793 }
794
795 clientdata->features = id->driver_data;
796 i2c_set_clientdata(client, clientdata);
797
798 rtc = rtc_device_register(client->name, &client->dev,
799 &m41t80_rtc_ops, THIS_MODULE);
800 if (IS_ERR(rtc)) {
801 rc = PTR_ERR(rtc);
802 rtc = NULL;
803 goto exit;
804 }
805
806 clientdata->rtc = rtc;
807
808 /* Make sure HT (Halt Update) bit is cleared */
809 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
810 if (rc < 0)
811 goto ht_err;
812
813 if (rc & M41T80_ALHOUR_HT) {
814 if (clientdata->features & M41T80_FEATURE_HT) {
815 m41t80_get_datetime(client, &tm);
816 dev_info(&client->dev, "HT bit was set!\n");
817 dev_info(&client->dev,
818 "Power Down at "
819 "%04i-%02i-%02i %02i:%02i:%02i\n",
820 tm.tm_year + 1900,
821 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
822 tm.tm_min, tm.tm_sec);
823 }
824 if (i2c_smbus_write_byte_data(client,
825 M41T80_REG_ALARM_HOUR,
826 rc & ~M41T80_ALHOUR_HT) < 0)
827 goto ht_err;
828 }
829
830 /* Make sure ST (stop) bit is cleared */
831 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
832 if (rc < 0)
833 goto st_err;
834
835 if (rc & M41T80_SEC_ST) {
836 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
837 rc & ~M41T80_SEC_ST) < 0)
838 goto st_err;
839 }
840
841 rc = m41t80_sysfs_register(&client->dev);
842 if (rc)
843 goto exit;
844
845 #ifdef CONFIG_RTC_DRV_M41T80_WDT
846 if (clientdata->features & M41T80_FEATURE_HT) {
847 save_client = client;
848 rc = misc_register(&wdt_dev);
849 if (rc)
850 goto exit;
851 rc = register_reboot_notifier(&wdt_notifier);
852 if (rc) {
853 misc_deregister(&wdt_dev);
854 goto exit;
855 }
856 }
857 #endif
858 return 0;
859
860 st_err:
861 rc = -EIO;
862 dev_err(&client->dev, "Can't clear ST bit\n");
863 goto exit;
864 ht_err:
865 rc = -EIO;
866 dev_err(&client->dev, "Can't clear HT bit\n");
867 goto exit;
868
869 exit:
870 if (rtc)
871 rtc_device_unregister(rtc);
872 kfree(clientdata);
873 return rc;
874 }
875
876 static int m41t80_remove(struct i2c_client *client)
877 {
878 struct m41t80_data *clientdata = i2c_get_clientdata(client);
879 struct rtc_device *rtc = clientdata->rtc;
880
881 #ifdef CONFIG_RTC_DRV_M41T80_WDT
882 if (clientdata->features & M41T80_FEATURE_HT) {
883 misc_deregister(&wdt_dev);
884 unregister_reboot_notifier(&wdt_notifier);
885 }
886 #endif
887 if (rtc)
888 rtc_device_unregister(rtc);
889 kfree(clientdata);
890
891 return 0;
892 }
893
894 static struct i2c_driver m41t80_driver = {
895 .driver = {
896 .name = "rtc-m41t80",
897 },
898 .probe = m41t80_probe,
899 .remove = m41t80_remove,
900 .id_table = m41t80_id,
901 };
902
903 static int __init m41t80_rtc_init(void)
904 {
905 return i2c_add_driver(&m41t80_driver);
906 }
907
908 static void __exit m41t80_rtc_exit(void)
909 {
910 i2c_del_driver(&m41t80_driver);
911 }
912
913 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
914 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
915 MODULE_LICENSE("GPL");
916 MODULE_VERSION(DRV_VERSION);
917
918 module_init(m41t80_rtc_init);
919 module_exit(m41t80_rtc_exit);
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