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mm: smaps: export mlock information
[linux-2.6/next.git] / drivers / rtc / rtc-m41t80.c
blob5a8daa358066a5564f61276fb9e5bccf0a3bf640
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 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
217 static int
218 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
219 {
220 struct i2c_client *client = to_i2c_client(dev);
221 int rc;
222
223 switch (cmd) {
224 case RTC_AIE_OFF:
225 case RTC_AIE_ON:
226 break;
227 default:
228 return -ENOIOCTLCMD;
229 }
230
231 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
232 if (rc < 0)
233 goto err;
234 switch (cmd) {
235 case RTC_AIE_OFF:
236 rc &= ~M41T80_ALMON_AFE;
237 break;
238 case RTC_AIE_ON:
239 rc |= M41T80_ALMON_AFE;
240 break;
241 }
242 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
243 goto err;
244 return 0;
245 err:
246 return -EIO;
247 }
248 #else
249 #define m41t80_rtc_ioctl NULL
250 #endif
251
252 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
253 {
254 struct i2c_client *client = to_i2c_client(dev);
255 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
256 u8 *buf = &wbuf[1];
257 u8 *reg = buf - M41T80_REG_ALARM_MON;
258 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
259 struct i2c_msg msgs_in[] = {
260 {
261 .addr = client->addr,
262 .flags = 0,
263 .len = 1,
264 .buf = dt_addr,
265 },
266 {
267 .addr = client->addr,
268 .flags = I2C_M_RD,
269 .len = M41T80_ALARM_REG_SIZE,
270 .buf = buf,
271 },
272 };
273 struct i2c_msg msgs[] = {
274 {
275 .addr = client->addr,
276 .flags = 0,
277 .len = 1 + M41T80_ALARM_REG_SIZE,
278 .buf = wbuf,
279 },
280 };
281
282 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
283 dev_err(&client->dev, "read error\n");
284 return -EIO;
285 }
286 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
287 reg[M41T80_REG_ALARM_DAY] = 0;
288 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
289 reg[M41T80_REG_ALARM_MIN] = 0;
290 reg[M41T80_REG_ALARM_SEC] = 0;
291
292 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
293 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
294 bin2bcd(t->time.tm_sec) : 0x80;
295 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
296 bin2bcd(t->time.tm_min) : 0x80;
297 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
298 bin2bcd(t->time.tm_hour) : 0x80;
299 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
300 bin2bcd(t->time.tm_mday) : 0x80;
301 if (t->time.tm_mon >= 0)
302 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
303 else
304 reg[M41T80_REG_ALARM_DAY] |= 0x40;
305
306 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
307 dev_err(&client->dev, "write error\n");
308 return -EIO;
309 }
310
311 if (t->enabled) {
312 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
313 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
314 reg[M41T80_REG_ALARM_MON]) < 0) {
315 dev_err(&client->dev, "write error\n");
316 return -EIO;
317 }
318 }
319 return 0;
320 }
321
322 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
323 {
324 struct i2c_client *client = to_i2c_client(dev);
325 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
326 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
327 u8 *reg = buf - M41T80_REG_ALARM_MON;
328 struct i2c_msg msgs[] = {
329 {
330 .addr = client->addr,
331 .flags = 0,
332 .len = 1,
333 .buf = dt_addr,
334 },
335 {
336 .addr = client->addr,
337 .flags = I2C_M_RD,
338 .len = M41T80_ALARM_REG_SIZE + 1,
339 .buf = buf,
340 },
341 };
342
343 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
344 dev_err(&client->dev, "read error\n");
345 return -EIO;
346 }
347 t->time.tm_sec = -1;
348 t->time.tm_min = -1;
349 t->time.tm_hour = -1;
350 t->time.tm_mday = -1;
351 t->time.tm_mon = -1;
352 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
353 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
354 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
355 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
356 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
357 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
358 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
359 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
360 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
361 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
362 t->time.tm_year = -1;
363 t->time.tm_wday = -1;
364 t->time.tm_yday = -1;
365 t->time.tm_isdst = -1;
366 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
367 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
368 return 0;
369 }
370
371 static struct rtc_class_ops m41t80_rtc_ops = {
372 .read_time = m41t80_rtc_read_time,
373 .set_time = m41t80_rtc_set_time,
374 .read_alarm = m41t80_rtc_read_alarm,
375 .set_alarm = m41t80_rtc_set_alarm,
376 .proc = m41t80_rtc_proc,
377 .ioctl = m41t80_rtc_ioctl,
378 };
379
380 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
381 static ssize_t m41t80_sysfs_show_flags(struct device *dev,
382 struct device_attribute *attr, char *buf)
383 {
384 struct i2c_client *client = to_i2c_client(dev);
385 int val;
386
387 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
388 if (val < 0)
389 return -EIO;
390 return sprintf(buf, "%#x\n", val);
391 }
392 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
393
394 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
395 struct device_attribute *attr, char *buf)
396 {
397 struct i2c_client *client = to_i2c_client(dev);
398 struct m41t80_data *clientdata = i2c_get_clientdata(client);
399 int val, reg_sqw;
400
401 if (!(clientdata->features & M41T80_FEATURE_SQ))
402 return -EINVAL;
403
404 reg_sqw = M41T80_REG_SQW;
405 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
406 reg_sqw = M41T80_REG_WDAY;
407 val = i2c_smbus_read_byte_data(client, reg_sqw);
408 if (val < 0)
409 return -EIO;
410 val = (val >> 4) & 0xf;
411 switch (val) {
412 case 0:
413 break;
414 case 1:
415 val = 32768;
416 break;
417 default:
418 val = 32768 >> val;
419 }
420 return sprintf(buf, "%d\n", val);
421 }
422 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
423 struct device_attribute *attr,
424 const char *buf, size_t count)
425 {
426 struct i2c_client *client = to_i2c_client(dev);
427 struct m41t80_data *clientdata = i2c_get_clientdata(client);
428 int almon, sqw, reg_sqw;
429 int val = simple_strtoul(buf, NULL, 0);
430
431 if (!(clientdata->features & M41T80_FEATURE_SQ))
432 return -EINVAL;
433
434 if (val) {
435 if (!is_power_of_2(val))
436 return -EINVAL;
437 val = ilog2(val);
438 if (val == 15)
439 val = 1;
440 else if (val < 14)
441 val = 15 - val;
442 else
443 return -EINVAL;
444 }
445 /* disable SQW, set SQW frequency & re-enable */
446 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
447 if (almon < 0)
448 return -EIO;
449 reg_sqw = M41T80_REG_SQW;
450 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
451 reg_sqw = M41T80_REG_WDAY;
452 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
453 if (sqw < 0)
454 return -EIO;
455 sqw = (sqw & 0x0f) | (val << 4);
456 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
457 almon & ~M41T80_ALMON_SQWE) < 0 ||
458 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
459 return -EIO;
460 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
461 almon | M41T80_ALMON_SQWE) < 0)
462 return -EIO;
463 return count;
464 }
465 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
466 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
467
468 static struct attribute *attrs[] = {
469 &dev_attr_flags.attr,
470 &dev_attr_sqwfreq.attr,
471 NULL,
472 };
473 static struct attribute_group attr_group = {
474 .attrs = attrs,
475 };
476
477 static int m41t80_sysfs_register(struct device *dev)
478 {
479 return sysfs_create_group(&dev->kobj, &attr_group);
480 }
481 #else
482 static int m41t80_sysfs_register(struct device *dev)
483 {
484 return 0;
485 }
486 #endif
487
488 #ifdef CONFIG_RTC_DRV_M41T80_WDT
489 /*
490 *****************************************************************************
491 *
492 * Watchdog Driver
493 *
494 *****************************************************************************
495 */
496 static struct i2c_client *save_client;
497
498 /* Default margin */
499 #define WD_TIMO 60 /* 1..31 seconds */
500
501 static int wdt_margin = WD_TIMO;
502 module_param(wdt_margin, int, 0);
503 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
504
505 static unsigned long wdt_is_open;
506 static int boot_flag;
507
508 /**
509 * wdt_ping:
510 *
511 * Reload counter one with the watchdog timeout. We don't bother reloading
512 * the cascade counter.
513 */
514 static void wdt_ping(void)
515 {
516 unsigned char i2c_data[2];
517 struct i2c_msg msgs1[1] = {
518 {
519 .addr = save_client->addr,
520 .flags = 0,
521 .len = 2,
522 .buf = i2c_data,
523 },
524 };
525 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
526
527 i2c_data[0] = 0x09; /* watchdog register */
528
529 if (wdt_margin > 31)
530 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
531 else
532 /*
533 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
534 */
535 i2c_data[1] = wdt_margin<<2 | 0x82;
536
537 /*
538 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
539 * that would be an invalid resolution.
540 */
541 if (clientdata->features & M41T80_FEATURE_WD)
542 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
543
544 i2c_transfer(save_client->adapter, msgs1, 1);
545 }
546
547 /**
548 * wdt_disable:
549 *
550 * disables watchdog.
551 */
552 static void wdt_disable(void)
553 {
554 unsigned char i2c_data[2], i2c_buf[0x10];
555 struct i2c_msg msgs0[2] = {
556 {
557 .addr = save_client->addr,
558 .flags = 0,
559 .len = 1,
560 .buf = i2c_data,
561 },
562 {
563 .addr = save_client->addr,
564 .flags = I2C_M_RD,
565 .len = 1,
566 .buf = i2c_buf,
567 },
568 };
569 struct i2c_msg msgs1[1] = {
570 {
571 .addr = save_client->addr,
572 .flags = 0,
573 .len = 2,
574 .buf = i2c_data,
575 },
576 };
577
578 i2c_data[0] = 0x09;
579 i2c_transfer(save_client->adapter, msgs0, 2);
580
581 i2c_data[0] = 0x09;
582 i2c_data[1] = 0x00;
583 i2c_transfer(save_client->adapter, msgs1, 1);
584 }
585
586 /**
587 * wdt_write:
588 * @file: file handle to the watchdog
589 * @buf: buffer to write (unused as data does not matter here
590 * @count: count of bytes
591 * @ppos: pointer to the position to write. No seeks allowed
592 *
593 * A write to a watchdog device is defined as a keepalive signal. Any
594 * write of data will do, as we we don't define content meaning.
595 */
596 static ssize_t wdt_write(struct file *file, const char __user *buf,
597 size_t count, loff_t *ppos)
598 {
599 if (count) {
600 wdt_ping();
601 return 1;
602 }
603 return 0;
604 }
605
606 static ssize_t wdt_read(struct file *file, char __user *buf,
607 size_t count, loff_t *ppos)
608 {
609 return 0;
610 }
611
612 /**
613 * wdt_ioctl:
614 * @inode: inode of the device
615 * @file: file handle to the device
616 * @cmd: watchdog command
617 * @arg: argument pointer
618 *
619 * The watchdog API defines a common set of functions for all watchdogs
620 * according to their available features. We only actually usefully support
621 * querying capabilities and current status.
622 */
623 static int wdt_ioctl(struct file *file, unsigned int cmd,
624 unsigned long arg)
625 {
626 int new_margin, rv;
627 static struct watchdog_info ident = {
628 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
629 WDIOF_SETTIMEOUT,
630 .firmware_version = 1,
631 .identity = "M41T80 WTD"
632 };
633
634 switch (cmd) {
635 case WDIOC_GETSUPPORT:
636 return copy_to_user((struct watchdog_info __user *)arg, &ident,
637 sizeof(ident)) ? -EFAULT : 0;
638
639 case WDIOC_GETSTATUS:
640 case WDIOC_GETBOOTSTATUS:
641 return put_user(boot_flag, (int __user *)arg);
642 case WDIOC_KEEPALIVE:
643 wdt_ping();
644 return 0;
645 case WDIOC_SETTIMEOUT:
646 if (get_user(new_margin, (int __user *)arg))
647 return -EFAULT;
648 /* Arbitrary, can't find the card's limits */
649 if (new_margin < 1 || new_margin > 124)
650 return -EINVAL;
651 wdt_margin = new_margin;
652 wdt_ping();
653 /* Fall */
654 case WDIOC_GETTIMEOUT:
655 return put_user(wdt_margin, (int __user *)arg);
656
657 case WDIOC_SETOPTIONS:
658 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
659 return -EFAULT;
660
661 if (rv & WDIOS_DISABLECARD) {
662 pr_info("rtc-m41t80: disable watchdog\n");
663 wdt_disable();
664 }
665
666 if (rv & WDIOS_ENABLECARD) {
667 pr_info("rtc-m41t80: enable watchdog\n");
668 wdt_ping();
669 }
670
671 return -EINVAL;
672 }
673 return -ENOTTY;
674 }
675
676 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
677 unsigned long arg)
678 {
679 int ret;
680
681 mutex_lock(&m41t80_rtc_mutex);
682 ret = wdt_ioctl(file, cmd, arg);
683 mutex_unlock(&m41t80_rtc_mutex);
684
685 return ret;
686 }
687
688 /**
689 * wdt_open:
690 * @inode: inode of device
691 * @file: file handle to device
692 *
693 */
694 static int wdt_open(struct inode *inode, struct file *file)
695 {
696 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
697 mutex_lock(&m41t80_rtc_mutex);
698 if (test_and_set_bit(0, &wdt_is_open)) {
699 mutex_unlock(&m41t80_rtc_mutex);
700 return -EBUSY;
701 }
702 /*
703 * Activate
704 */
705 wdt_is_open = 1;
706 mutex_unlock(&m41t80_rtc_mutex);
707 return nonseekable_open(inode, file);
708 }
709 return -ENODEV;
710 }
711
712 /**
713 * wdt_close:
714 * @inode: inode to board
715 * @file: file handle to board
716 *
717 */
718 static int wdt_release(struct inode *inode, struct file *file)
719 {
720 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
721 clear_bit(0, &wdt_is_open);
722 return 0;
723 }
724
725 /**
726 * notify_sys:
727 * @this: our notifier block
728 * @code: the event being reported
729 * @unused: unused
730 *
731 * Our notifier is called on system shutdowns. We want to turn the card
732 * off at reboot otherwise the machine will reboot again during memory
733 * test or worse yet during the following fsck. This would suck, in fact
734 * trust me - if it happens it does suck.
735 */
736 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
737 void *unused)
738 {
739 if (code == SYS_DOWN || code == SYS_HALT)
740 /* Disable Watchdog */
741 wdt_disable();
742 return NOTIFY_DONE;
743 }
744
745 static const struct file_operations wdt_fops = {
746 .owner = THIS_MODULE,
747 .read = wdt_read,
748 .unlocked_ioctl = wdt_unlocked_ioctl,
749 .write = wdt_write,
750 .open = wdt_open,
751 .release = wdt_release,
752 .llseek = no_llseek,
753 };
754
755 static struct miscdevice wdt_dev = {
756 .minor = WATCHDOG_MINOR,
757 .name = "watchdog",
758 .fops = &wdt_fops,
759 };
760
761 /*
762 * The WDT card needs to learn about soft shutdowns in order to
763 * turn the timebomb registers off.
764 */
765 static struct notifier_block wdt_notifier = {
766 .notifier_call = wdt_notify_sys,
767 };
768 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
769
770 /*
771 *****************************************************************************
772 *
773 * Driver Interface
774 *
775 *****************************************************************************
776 */
777 static int m41t80_probe(struct i2c_client *client,
778 const struct i2c_device_id *id)
779 {
780 int rc = 0;
781 struct rtc_device *rtc = NULL;
782 struct rtc_time tm;
783 struct m41t80_data *clientdata = NULL;
784
785 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
786 | I2C_FUNC_SMBUS_BYTE_DATA)) {
787 rc = -ENODEV;
788 goto exit;
789 }
790
791 dev_info(&client->dev,
792 "chip found, driver version " DRV_VERSION "\n");
793
794 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
795 if (!clientdata) {
796 rc = -ENOMEM;
797 goto exit;
798 }
799
800 rtc = rtc_device_register(client->name, &client->dev,
801 &m41t80_rtc_ops, THIS_MODULE);
802 if (IS_ERR(rtc)) {
803 rc = PTR_ERR(rtc);
804 rtc = NULL;
805 goto exit;
806 }
807
808 clientdata->rtc = rtc;
809 clientdata->features = id->driver_data;
810 i2c_set_clientdata(client, clientdata);
811
812 /* Make sure HT (Halt Update) bit is cleared */
813 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
814 if (rc < 0)
815 goto ht_err;
816
817 if (rc & M41T80_ALHOUR_HT) {
818 if (clientdata->features & M41T80_FEATURE_HT) {
819 m41t80_get_datetime(client, &tm);
820 dev_info(&client->dev, "HT bit was set!\n");
821 dev_info(&client->dev,
822 "Power Down at "
823 "%04i-%02i-%02i %02i:%02i:%02i\n",
824 tm.tm_year + 1900,
825 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
826 tm.tm_min, tm.tm_sec);
827 }
828 if (i2c_smbus_write_byte_data(client,
829 M41T80_REG_ALARM_HOUR,
830 rc & ~M41T80_ALHOUR_HT) < 0)
831 goto ht_err;
832 }
833
834 /* Make sure ST (stop) bit is cleared */
835 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
836 if (rc < 0)
837 goto st_err;
838
839 if (rc & M41T80_SEC_ST) {
840 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
841 rc & ~M41T80_SEC_ST) < 0)
842 goto st_err;
843 }
844
845 rc = m41t80_sysfs_register(&client->dev);
846 if (rc)
847 goto exit;
848
849 #ifdef CONFIG_RTC_DRV_M41T80_WDT
850 if (clientdata->features & M41T80_FEATURE_HT) {
851 save_client = client;
852 rc = misc_register(&wdt_dev);
853 if (rc)
854 goto exit;
855 rc = register_reboot_notifier(&wdt_notifier);
856 if (rc) {
857 misc_deregister(&wdt_dev);
858 goto exit;
859 }
860 }
861 #endif
862 return 0;
863
864 st_err:
865 rc = -EIO;
866 dev_err(&client->dev, "Can't clear ST bit\n");
867 goto exit;
868 ht_err:
869 rc = -EIO;
870 dev_err(&client->dev, "Can't clear HT bit\n");
871 goto exit;
872
873 exit:
874 if (rtc)
875 rtc_device_unregister(rtc);
876 kfree(clientdata);
877 return rc;
878 }
879
880 static int m41t80_remove(struct i2c_client *client)
881 {
882 struct m41t80_data *clientdata = i2c_get_clientdata(client);
883 struct rtc_device *rtc = clientdata->rtc;
884
885 #ifdef CONFIG_RTC_DRV_M41T80_WDT
886 if (clientdata->features & M41T80_FEATURE_HT) {
887 misc_deregister(&wdt_dev);
888 unregister_reboot_notifier(&wdt_notifier);
889 }
890 #endif
891 if (rtc)
892 rtc_device_unregister(rtc);
893 kfree(clientdata);
894
895 return 0;
896 }
897
898 static struct i2c_driver m41t80_driver = {
899 .driver = {
900 .name = "rtc-m41t80",
901 },
902 .probe = m41t80_probe,
903 .remove = m41t80_remove,
904 .id_table = m41t80_id,
905 };
906
907 static int __init m41t80_rtc_init(void)
908 {
909 return i2c_add_driver(&m41t80_driver);
910 }
911
912 static void __exit m41t80_rtc_exit(void)
913 {
914 i2c_del_driver(&m41t80_driver);
915 }
916
917 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
918 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
919 MODULE_LICENSE("GPL");
920 MODULE_VERSION(DRV_VERSION);
921
922 module_init(m41t80_rtc_init);
923 module_exit(m41t80_rtc_exit);
linux-next