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zfcp: Report scatter gather limit for DIX protection information
[linux-2.6/next.git] / drivers / rtc / rtc-m41t80.c
blob66377f3e28b851eaa908c6057a9646a639e9c229
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/smp_lock.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 const struct i2c_device_id m41t80_id[] = {
72 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
73 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
74 { "m41t80", M41T80_FEATURE_SQ },
75 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
76 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
77 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { }
83 };
84 MODULE_DEVICE_TABLE(i2c, m41t80_id);
85
86 struct m41t80_data {
87 u8 features;
88 struct rtc_device *rtc;
89 };
90
91 static int m41t80_get_datetime(struct i2c_client *client,
92 struct rtc_time *tm)
93 {
94 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
95 struct i2c_msg msgs[] = {
96 {
97 .addr = client->addr,
98 .flags = 0,
99 .len = 1,
100 .buf = dt_addr,
101 },
102 {
103 .addr = client->addr,
104 .flags = I2C_M_RD,
105 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
106 .buf = buf + M41T80_REG_SEC,
107 },
108 };
109
110 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
111 dev_err(&client->dev, "read error\n");
112 return -EIO;
113 }
114
115 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
116 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
117 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
118 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
119 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
120 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
121
122 /* assume 20YY not 19YY, and ignore the Century Bit */
123 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
124 return rtc_valid_tm(tm);
125 }
126
127 /* Sets the given date and time to the real time clock. */
128 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
129 {
130 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
131 u8 *buf = &wbuf[1];
132 u8 dt_addr[1] = { M41T80_REG_SEC };
133 struct i2c_msg msgs_in[] = {
134 {
135 .addr = client->addr,
136 .flags = 0,
137 .len = 1,
138 .buf = dt_addr,
139 },
140 {
141 .addr = client->addr,
142 .flags = I2C_M_RD,
143 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
144 .buf = buf + M41T80_REG_SEC,
145 },
146 };
147 struct i2c_msg msgs[] = {
148 {
149 .addr = client->addr,
150 .flags = 0,
151 .len = 1 + M41T80_DATETIME_REG_SIZE,
152 .buf = wbuf,
153 },
154 };
155
156 /* Read current reg values into buf[1..7] */
157 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
158 dev_err(&client->dev, "read error\n");
159 return -EIO;
160 }
161
162 wbuf[0] = 0; /* offset into rtc's regs */
163 /* Merge time-data and register flags into buf[0..7] */
164 buf[M41T80_REG_SSEC] = 0;
165 buf[M41T80_REG_SEC] =
166 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
167 buf[M41T80_REG_MIN] =
168 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
169 buf[M41T80_REG_HOUR] =
170 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
171 buf[M41T80_REG_WDAY] =
172 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
173 buf[M41T80_REG_DAY] =
174 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
175 buf[M41T80_REG_MON] =
176 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
177 /* assume 20YY not 19YY */
178 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
179
180 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
181 dev_err(&client->dev, "write error\n");
182 return -EIO;
183 }
184 return 0;
185 }
186
187 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
188 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
189 {
190 struct i2c_client *client = to_i2c_client(dev);
191 struct m41t80_data *clientdata = i2c_get_clientdata(client);
192 u8 reg;
193
194 if (clientdata->features & M41T80_FEATURE_BL) {
195 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
196 seq_printf(seq, "battery\t\t: %s\n",
197 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
198 }
199 return 0;
200 }
201 #else
202 #define m41t80_rtc_proc NULL
203 #endif
204
205 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
206 {
207 return m41t80_get_datetime(to_i2c_client(dev), tm);
208 }
209
210 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
211 {
212 return m41t80_set_datetime(to_i2c_client(dev), tm);
213 }
214
215 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
216 static int
217 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
218 {
219 struct i2c_client *client = to_i2c_client(dev);
220 int rc;
221
222 switch (cmd) {
223 case RTC_AIE_OFF:
224 case RTC_AIE_ON:
225 break;
226 default:
227 return -ENOIOCTLCMD;
228 }
229
230 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
231 if (rc < 0)
232 goto err;
233 switch (cmd) {
234 case RTC_AIE_OFF:
235 rc &= ~M41T80_ALMON_AFE;
236 break;
237 case RTC_AIE_ON:
238 rc |= M41T80_ALMON_AFE;
239 break;
240 }
241 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
242 goto err;
243 return 0;
244 err:
245 return -EIO;
246 }
247 #else
248 #define m41t80_rtc_ioctl NULL
249 #endif
250
251 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
252 {
253 struct i2c_client *client = to_i2c_client(dev);
254 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
255 u8 *buf = &wbuf[1];
256 u8 *reg = buf - M41T80_REG_ALARM_MON;
257 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
258 struct i2c_msg msgs_in[] = {
259 {
260 .addr = client->addr,
261 .flags = 0,
262 .len = 1,
263 .buf = dt_addr,
264 },
265 {
266 .addr = client->addr,
267 .flags = I2C_M_RD,
268 .len = M41T80_ALARM_REG_SIZE,
269 .buf = buf,
270 },
271 };
272 struct i2c_msg msgs[] = {
273 {
274 .addr = client->addr,
275 .flags = 0,
276 .len = 1 + M41T80_ALARM_REG_SIZE,
277 .buf = wbuf,
278 },
279 };
280
281 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
282 dev_err(&client->dev, "read error\n");
283 return -EIO;
284 }
285 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
286 reg[M41T80_REG_ALARM_DAY] = 0;
287 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
288 reg[M41T80_REG_ALARM_MIN] = 0;
289 reg[M41T80_REG_ALARM_SEC] = 0;
290
291 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
292 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
293 bin2bcd(t->time.tm_sec) : 0x80;
294 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
295 bin2bcd(t->time.tm_min) : 0x80;
296 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
297 bin2bcd(t->time.tm_hour) : 0x80;
298 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
299 bin2bcd(t->time.tm_mday) : 0x80;
300 if (t->time.tm_mon >= 0)
301 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
302 else
303 reg[M41T80_REG_ALARM_DAY] |= 0x40;
304
305 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
306 dev_err(&client->dev, "write error\n");
307 return -EIO;
308 }
309
310 if (t->enabled) {
311 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
312 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
313 reg[M41T80_REG_ALARM_MON]) < 0) {
314 dev_err(&client->dev, "write error\n");
315 return -EIO;
316 }
317 }
318 return 0;
319 }
320
321 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
322 {
323 struct i2c_client *client = to_i2c_client(dev);
324 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
325 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
326 u8 *reg = buf - M41T80_REG_ALARM_MON;
327 struct i2c_msg msgs[] = {
328 {
329 .addr = client->addr,
330 .flags = 0,
331 .len = 1,
332 .buf = dt_addr,
333 },
334 {
335 .addr = client->addr,
336 .flags = I2C_M_RD,
337 .len = M41T80_ALARM_REG_SIZE + 1,
338 .buf = buf,
339 },
340 };
341
342 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
343 dev_err(&client->dev, "read error\n");
344 return -EIO;
345 }
346 t->time.tm_sec = -1;
347 t->time.tm_min = -1;
348 t->time.tm_hour = -1;
349 t->time.tm_mday = -1;
350 t->time.tm_mon = -1;
351 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
352 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
353 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
354 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
355 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
356 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
357 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
358 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
359 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
360 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
361 t->time.tm_year = -1;
362 t->time.tm_wday = -1;
363 t->time.tm_yday = -1;
364 t->time.tm_isdst = -1;
365 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
366 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
367 return rtc_valid_tm(t);
368 }
369
370 static struct rtc_class_ops m41t80_rtc_ops = {
371 .read_time = m41t80_rtc_read_time,
372 .set_time = m41t80_rtc_set_time,
373 .read_alarm = m41t80_rtc_read_alarm,
374 .set_alarm = m41t80_rtc_set_alarm,
375 .proc = m41t80_rtc_proc,
376 .ioctl = m41t80_rtc_ioctl,
377 };
378
379 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
380 static ssize_t m41t80_sysfs_show_flags(struct device *dev,
381 struct device_attribute *attr, char *buf)
382 {
383 struct i2c_client *client = to_i2c_client(dev);
384 int val;
385
386 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
387 if (val < 0)
388 return -EIO;
389 return sprintf(buf, "%#x\n", val);
390 }
391 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
392
393 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
394 struct device_attribute *attr, char *buf)
395 {
396 struct i2c_client *client = to_i2c_client(dev);
397 struct m41t80_data *clientdata = i2c_get_clientdata(client);
398 int val, reg_sqw;
399
400 if (!(clientdata->features & M41T80_FEATURE_SQ))
401 return -EINVAL;
402
403 reg_sqw = M41T80_REG_SQW;
404 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
405 reg_sqw = M41T80_REG_WDAY;
406 val = i2c_smbus_read_byte_data(client, reg_sqw);
407 if (val < 0)
408 return -EIO;
409 val = (val >> 4) & 0xf;
410 switch (val) {
411 case 0:
412 break;
413 case 1:
414 val = 32768;
415 break;
416 default:
417 val = 32768 >> val;
418 }
419 return sprintf(buf, "%d\n", val);
420 }
421 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
422 struct device_attribute *attr,
423 const char *buf, size_t count)
424 {
425 struct i2c_client *client = to_i2c_client(dev);
426 struct m41t80_data *clientdata = i2c_get_clientdata(client);
427 int almon, sqw, reg_sqw;
428 int val = simple_strtoul(buf, NULL, 0);
429
430 if (!(clientdata->features & M41T80_FEATURE_SQ))
431 return -EINVAL;
432
433 if (val) {
434 if (!is_power_of_2(val))
435 return -EINVAL;
436 val = ilog2(val);
437 if (val == 15)
438 val = 1;
439 else if (val < 14)
440 val = 15 - val;
441 else
442 return -EINVAL;
443 }
444 /* disable SQW, set SQW frequency & re-enable */
445 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
446 if (almon < 0)
447 return -EIO;
448 reg_sqw = M41T80_REG_SQW;
449 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
450 reg_sqw = M41T80_REG_WDAY;
451 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
452 if (sqw < 0)
453 return -EIO;
454 sqw = (sqw & 0x0f) | (val << 4);
455 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
456 almon & ~M41T80_ALMON_SQWE) < 0 ||
457 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
458 return -EIO;
459 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
460 almon | M41T80_ALMON_SQWE) < 0)
461 return -EIO;
462 return count;
463 }
464 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
465 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
466
467 static struct attribute *attrs[] = {
468 &dev_attr_flags.attr,
469 &dev_attr_sqwfreq.attr,
470 NULL,
471 };
472 static struct attribute_group attr_group = {
473 .attrs = attrs,
474 };
475
476 static int m41t80_sysfs_register(struct device *dev)
477 {
478 return sysfs_create_group(&dev->kobj, &attr_group);
479 }
480 #else
481 static int m41t80_sysfs_register(struct device *dev)
482 {
483 return 0;
484 }
485 #endif
486
487 #ifdef CONFIG_RTC_DRV_M41T80_WDT
488 /*
489 *****************************************************************************
490 *
491 * Watchdog Driver
492 *
493 *****************************************************************************
494 */
495 static struct i2c_client *save_client;
496
497 /* Default margin */
498 #define WD_TIMO 60 /* 1..31 seconds */
499
500 static int wdt_margin = WD_TIMO;
501 module_param(wdt_margin, int, 0);
502 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
503
504 static unsigned long wdt_is_open;
505 static int boot_flag;
506
507 /**
508 * wdt_ping:
509 *
510 * Reload counter one with the watchdog timeout. We don't bother reloading
511 * the cascade counter.
512 */
513 static void wdt_ping(void)
514 {
515 unsigned char i2c_data[2];
516 struct i2c_msg msgs1[1] = {
517 {
518 .addr = save_client->addr,
519 .flags = 0,
520 .len = 2,
521 .buf = i2c_data,
522 },
523 };
524 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
525
526 i2c_data[0] = 0x09; /* watchdog register */
527
528 if (wdt_margin > 31)
529 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
530 else
531 /*
532 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
533 */
534 i2c_data[1] = wdt_margin<<2 | 0x82;
535
536 /*
537 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
538 * that would be an invalid resolution.
539 */
540 if (clientdata->features & M41T80_FEATURE_WD)
541 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
542
543 i2c_transfer(save_client->adapter, msgs1, 1);
544 }
545
546 /**
547 * wdt_disable:
548 *
549 * disables watchdog.
550 */
551 static void wdt_disable(void)
552 {
553 unsigned char i2c_data[2], i2c_buf[0x10];
554 struct i2c_msg msgs0[2] = {
555 {
556 .addr = save_client->addr,
557 .flags = 0,
558 .len = 1,
559 .buf = i2c_data,
560 },
561 {
562 .addr = save_client->addr,
563 .flags = I2C_M_RD,
564 .len = 1,
565 .buf = i2c_buf,
566 },
567 };
568 struct i2c_msg msgs1[1] = {
569 {
570 .addr = save_client->addr,
571 .flags = 0,
572 .len = 2,
573 .buf = i2c_data,
574 },
575 };
576
577 i2c_data[0] = 0x09;
578 i2c_transfer(save_client->adapter, msgs0, 2);
579
580 i2c_data[0] = 0x09;
581 i2c_data[1] = 0x00;
582 i2c_transfer(save_client->adapter, msgs1, 1);
583 }
584
585 /**
586 * wdt_write:
587 * @file: file handle to the watchdog
588 * @buf: buffer to write (unused as data does not matter here
589 * @count: count of bytes
590 * @ppos: pointer to the position to write. No seeks allowed
591 *
592 * A write to a watchdog device is defined as a keepalive signal. Any
593 * write of data will do, as we we don't define content meaning.
594 */
595 static ssize_t wdt_write(struct file *file, const char __user *buf,
596 size_t count, loff_t *ppos)
597 {
598 if (count) {
599 wdt_ping();
600 return 1;
601 }
602 return 0;
603 }
604
605 static ssize_t wdt_read(struct file *file, char __user *buf,
606 size_t count, loff_t *ppos)
607 {
608 return 0;
609 }
610
611 /**
612 * wdt_ioctl:
613 * @inode: inode of the device
614 * @file: file handle to the device
615 * @cmd: watchdog command
616 * @arg: argument pointer
617 *
618 * The watchdog API defines a common set of functions for all watchdogs
619 * according to their available features. We only actually usefully support
620 * querying capabilities and current status.
621 */
622 static int wdt_ioctl(struct file *file, unsigned int cmd,
623 unsigned long arg)
624 {
625 int new_margin, rv;
626 static struct watchdog_info ident = {
627 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
628 WDIOF_SETTIMEOUT,
629 .firmware_version = 1,
630 .identity = "M41T80 WTD"
631 };
632
633 switch (cmd) {
634 case WDIOC_GETSUPPORT:
635 return copy_to_user((struct watchdog_info __user *)arg, &ident,
636 sizeof(ident)) ? -EFAULT : 0;
637
638 case WDIOC_GETSTATUS:
639 case WDIOC_GETBOOTSTATUS:
640 return put_user(boot_flag, (int __user *)arg);
641 case WDIOC_KEEPALIVE:
642 wdt_ping();
643 return 0;
644 case WDIOC_SETTIMEOUT:
645 if (get_user(new_margin, (int __user *)arg))
646 return -EFAULT;
647 /* Arbitrary, can't find the card's limits */
648 if (new_margin < 1 || new_margin > 124)
649 return -EINVAL;
650 wdt_margin = new_margin;
651 wdt_ping();
652 /* Fall */
653 case WDIOC_GETTIMEOUT:
654 return put_user(wdt_margin, (int __user *)arg);
655
656 case WDIOC_SETOPTIONS:
657 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
658 return -EFAULT;
659
660 if (rv & WDIOS_DISABLECARD) {
661 pr_info("rtc-m41t80: disable watchdog\n");
662 wdt_disable();
663 }
664
665 if (rv & WDIOS_ENABLECARD) {
666 pr_info("rtc-m41t80: enable watchdog\n");
667 wdt_ping();
668 }
669
670 return -EINVAL;
671 }
672 return -ENOTTY;
673 }
674
675 static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
676 unsigned long arg)
677 {
678 int ret;
679
680 lock_kernel();
681 ret = wdt_ioctl(file, cmd, arg);
682 unlock_kernel();
683
684 return ret;
685 }
686
687 /**
688 * wdt_open:
689 * @inode: inode of device
690 * @file: file handle to device
691 *
692 */
693 static int wdt_open(struct inode *inode, struct file *file)
694 {
695 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
696 lock_kernel();
697 if (test_and_set_bit(0, &wdt_is_open)) {
698 unlock_kernel();
699 return -EBUSY;
700 }
701 /*
702 * Activate
703 */
704 wdt_is_open = 1;
705 unlock_kernel();
706 return nonseekable_open(inode, file);
707 }
708 return -ENODEV;
709 }
710
711 /**
712 * wdt_close:
713 * @inode: inode to board
714 * @file: file handle to board
715 *
716 */
717 static int wdt_release(struct inode *inode, struct file *file)
718 {
719 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
720 clear_bit(0, &wdt_is_open);
721 return 0;
722 }
723
724 /**
725 * notify_sys:
726 * @this: our notifier block
727 * @code: the event being reported
728 * @unused: unused
729 *
730 * Our notifier is called on system shutdowns. We want to turn the card
731 * off at reboot otherwise the machine will reboot again during memory
732 * test or worse yet during the following fsck. This would suck, in fact
733 * trust me - if it happens it does suck.
734 */
735 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
736 void *unused)
737 {
738 if (code == SYS_DOWN || code == SYS_HALT)
739 /* Disable Watchdog */
740 wdt_disable();
741 return NOTIFY_DONE;
742 }
743
744 static const struct file_operations wdt_fops = {
745 .owner = THIS_MODULE,
746 .read = wdt_read,
747 .unlocked_ioctl = wdt_unlocked_ioctl,
748 .write = wdt_write,
749 .open = wdt_open,
750 .release = wdt_release,
751 };
752
753 static struct miscdevice wdt_dev = {
754 .minor = WATCHDOG_MINOR,
755 .name = "watchdog",
756 .fops = &wdt_fops,
757 };
758
759 /*
760 * The WDT card needs to learn about soft shutdowns in order to
761 * turn the timebomb registers off.
762 */
763 static struct notifier_block wdt_notifier = {
764 .notifier_call = wdt_notify_sys,
765 };
766 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
767
768 /*
769 *****************************************************************************
770 *
771 * Driver Interface
772 *
773 *****************************************************************************
774 */
775 static int m41t80_probe(struct i2c_client *client,
776 const struct i2c_device_id *id)
777 {
778 int rc = 0;
779 struct rtc_device *rtc = NULL;
780 struct rtc_time tm;
781 struct m41t80_data *clientdata = NULL;
782
783 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
784 | I2C_FUNC_SMBUS_BYTE_DATA)) {
785 rc = -ENODEV;
786 goto exit;
787 }
788
789 dev_info(&client->dev,
790 "chip found, driver version " DRV_VERSION "\n");
791
792 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
793 if (!clientdata) {
794 rc = -ENOMEM;
795 goto exit;
796 }
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 clientdata->features = id->driver_data;
808 i2c_set_clientdata(client, clientdata);
809
810 /* Make sure HT (Halt Update) bit is cleared */
811 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
812 if (rc < 0)
813 goto ht_err;
814
815 if (rc & M41T80_ALHOUR_HT) {
816 if (clientdata->features & M41T80_FEATURE_HT) {
817 m41t80_get_datetime(client, &tm);
818 dev_info(&client->dev, "HT bit was set!\n");
819 dev_info(&client->dev,
820 "Power Down at "
821 "%04i-%02i-%02i %02i:%02i:%02i\n",
822 tm.tm_year + 1900,
823 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
824 tm.tm_min, tm.tm_sec);
825 }
826 if (i2c_smbus_write_byte_data(client,
827 M41T80_REG_ALARM_HOUR,
828 rc & ~M41T80_ALHOUR_HT) < 0)
829 goto ht_err;
830 }
831
832 /* Make sure ST (stop) bit is cleared */
833 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
834 if (rc < 0)
835 goto st_err;
836
837 if (rc & M41T80_SEC_ST) {
838 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
839 rc & ~M41T80_SEC_ST) < 0)
840 goto st_err;
841 }
842
843 rc = m41t80_sysfs_register(&client->dev);
844 if (rc)
845 goto exit;
846
847 #ifdef CONFIG_RTC_DRV_M41T80_WDT
848 if (clientdata->features & M41T80_FEATURE_HT) {
849 save_client = client;
850 rc = misc_register(&wdt_dev);
851 if (rc)
852 goto exit;
853 rc = register_reboot_notifier(&wdt_notifier);
854 if (rc) {
855 misc_deregister(&wdt_dev);
856 goto exit;
857 }
858 }
859 #endif
860 return 0;
861
862 st_err:
863 rc = -EIO;
864 dev_err(&client->dev, "Can't clear ST bit\n");
865 goto exit;
866 ht_err:
867 rc = -EIO;
868 dev_err(&client->dev, "Can't clear HT bit\n");
869 goto exit;
870
871 exit:
872 if (rtc)
873 rtc_device_unregister(rtc);
874 kfree(clientdata);
875 return rc;
876 }
877
878 static int m41t80_remove(struct i2c_client *client)
879 {
880 struct m41t80_data *clientdata = i2c_get_clientdata(client);
881 struct rtc_device *rtc = clientdata->rtc;
882
883 #ifdef CONFIG_RTC_DRV_M41T80_WDT
884 if (clientdata->features & M41T80_FEATURE_HT) {
885 misc_deregister(&wdt_dev);
886 unregister_reboot_notifier(&wdt_notifier);
887 }
888 #endif
889 if (rtc)
890 rtc_device_unregister(rtc);
891 kfree(clientdata);
892
893 return 0;
894 }
895
896 static struct i2c_driver m41t80_driver = {
897 .driver = {
898 .name = "rtc-m41t80",
899 },
900 .probe = m41t80_probe,
901 .remove = m41t80_remove,
902 .id_table = m41t80_id,
903 };
904
905 static int __init m41t80_rtc_init(void)
906 {
907 return i2c_add_driver(&m41t80_driver);
908 }
909
910 static void __exit m41t80_rtc_exit(void)
911 {
912 i2c_del_driver(&m41t80_driver);
913 }
914
915 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
916 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
917 MODULE_LICENSE("GPL");
918 MODULE_VERSION(DRV_VERSION);
919
920 module_init(m41t80_rtc_init);
921 module_exit(m41t80_rtc_exit);
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