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Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6/mini2440.git] / drivers / rtc / rtc-m41t80.c
blob893f7dece239522afcca4579d2524dba58f645a0
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
68 #define DRV_VERSION "0.05"
69
70 static const struct i2c_device_id m41t80_id[] = {
71 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
72 { "m41t80", M41T80_FEATURE_SQ },
73 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
74 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
75 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
76 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
77 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { }
81 };
82 MODULE_DEVICE_TABLE(i2c, m41t80_id);
83
84 struct m41t80_data {
85 u8 features;
86 struct rtc_device *rtc;
87 };
88
89 static int m41t80_get_datetime(struct i2c_client *client,
90 struct rtc_time *tm)
91 {
92 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
93 struct i2c_msg msgs[] = {
94 {
95 .addr = client->addr,
96 .flags = 0,
97 .len = 1,
98 .buf = dt_addr,
99 },
100 {
101 .addr = client->addr,
102 .flags = I2C_M_RD,
103 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
104 .buf = buf + M41T80_REG_SEC,
105 },
106 };
107
108 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
109 dev_err(&client->dev, "read error\n");
110 return -EIO;
111 }
112
113 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
114 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
115 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
116 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
117 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
118 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
119
120 /* assume 20YY not 19YY, and ignore the Century Bit */
121 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
122 return 0;
123 }
124
125 /* Sets the given date and time to the real time clock. */
126 static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
127 {
128 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
129 u8 *buf = &wbuf[1];
130 u8 dt_addr[1] = { M41T80_REG_SEC };
131 struct i2c_msg msgs_in[] = {
132 {
133 .addr = client->addr,
134 .flags = 0,
135 .len = 1,
136 .buf = dt_addr,
137 },
138 {
139 .addr = client->addr,
140 .flags = I2C_M_RD,
141 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
142 .buf = buf + M41T80_REG_SEC,
143 },
144 };
145 struct i2c_msg msgs[] = {
146 {
147 .addr = client->addr,
148 .flags = 0,
149 .len = 1 + M41T80_DATETIME_REG_SIZE,
150 .buf = wbuf,
151 },
152 };
153
154 /* Read current reg values into buf[1..7] */
155 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
156 dev_err(&client->dev, "read error\n");
157 return -EIO;
158 }
159
160 wbuf[0] = 0; /* offset into rtc's regs */
161 /* Merge time-data and register flags into buf[0..7] */
162 buf[M41T80_REG_SSEC] = 0;
163 buf[M41T80_REG_SEC] =
164 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
165 buf[M41T80_REG_MIN] =
166 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
167 buf[M41T80_REG_HOUR] =
168 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
169 buf[M41T80_REG_WDAY] =
170 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
171 buf[M41T80_REG_DAY] =
172 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
173 buf[M41T80_REG_MON] =
174 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
175 /* assume 20YY not 19YY */
176 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
177
178 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
179 dev_err(&client->dev, "write error\n");
180 return -EIO;
181 }
182 return 0;
183 }
184
185 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
186 static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
187 {
188 struct i2c_client *client = to_i2c_client(dev);
189 struct m41t80_data *clientdata = i2c_get_clientdata(client);
190 u8 reg;
191
192 if (clientdata->features & M41T80_FEATURE_BL) {
193 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
194 seq_printf(seq, "battery\t\t: %s\n",
195 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
196 }
197 return 0;
198 }
199 #else
200 #define m41t80_rtc_proc NULL
201 #endif
202
203 static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
204 {
205 return m41t80_get_datetime(to_i2c_client(dev), tm);
206 }
207
208 static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
209 {
210 return m41t80_set_datetime(to_i2c_client(dev), tm);
211 }
212
213 #if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
214 static int
215 m41t80_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
216 {
217 struct i2c_client *client = to_i2c_client(dev);
218 int rc;
219
220 switch (cmd) {
221 case RTC_AIE_OFF:
222 case RTC_AIE_ON:
223 break;
224 default:
225 return -ENOIOCTLCMD;
226 }
227
228 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
229 if (rc < 0)
230 goto err;
231 switch (cmd) {
232 case RTC_AIE_OFF:
233 rc &= ~M41T80_ALMON_AFE;
234 break;
235 case RTC_AIE_ON:
236 rc |= M41T80_ALMON_AFE;
237 break;
238 }
239 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
240 goto err;
241 return 0;
242 err:
243 return -EIO;
244 }
245 #else
246 #define m41t80_rtc_ioctl NULL
247 #endif
248
249 static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
250 {
251 struct i2c_client *client = to_i2c_client(dev);
252 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
253 u8 *buf = &wbuf[1];
254 u8 *reg = buf - M41T80_REG_ALARM_MON;
255 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
256 struct i2c_msg msgs_in[] = {
257 {
258 .addr = client->addr,
259 .flags = 0,
260 .len = 1,
261 .buf = dt_addr,
262 },
263 {
264 .addr = client->addr,
265 .flags = I2C_M_RD,
266 .len = M41T80_ALARM_REG_SIZE,
267 .buf = buf,
268 },
269 };
270 struct i2c_msg msgs[] = {
271 {
272 .addr = client->addr,
273 .flags = 0,
274 .len = 1 + M41T80_ALARM_REG_SIZE,
275 .buf = wbuf,
276 },
277 };
278
279 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
280 dev_err(&client->dev, "read error\n");
281 return -EIO;
282 }
283 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
284 reg[M41T80_REG_ALARM_DAY] = 0;
285 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
286 reg[M41T80_REG_ALARM_MIN] = 0;
287 reg[M41T80_REG_ALARM_SEC] = 0;
288
289 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
290 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
291 bin2bcd(t->time.tm_sec) : 0x80;
292 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
293 bin2bcd(t->time.tm_min) : 0x80;
294 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
295 bin2bcd(t->time.tm_hour) : 0x80;
296 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
297 bin2bcd(t->time.tm_mday) : 0x80;
298 if (t->time.tm_mon >= 0)
299 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
300 else
301 reg[M41T80_REG_ALARM_DAY] |= 0x40;
302
303 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
304 dev_err(&client->dev, "write error\n");
305 return -EIO;
306 }
307
308 if (t->enabled) {
309 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
310 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
311 reg[M41T80_REG_ALARM_MON]) < 0) {
312 dev_err(&client->dev, "write error\n");
313 return -EIO;
314 }
315 }
316 return 0;
317 }
318
319 static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
320 {
321 struct i2c_client *client = to_i2c_client(dev);
322 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
323 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
324 u8 *reg = buf - M41T80_REG_ALARM_MON;
325 struct i2c_msg msgs[] = {
326 {
327 .addr = client->addr,
328 .flags = 0,
329 .len = 1,
330 .buf = dt_addr,
331 },
332 {
333 .addr = client->addr,
334 .flags = I2C_M_RD,
335 .len = M41T80_ALARM_REG_SIZE + 1,
336 .buf = buf,
337 },
338 };
339
340 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
341 dev_err(&client->dev, "read error\n");
342 return -EIO;
343 }
344 t->time.tm_sec = -1;
345 t->time.tm_min = -1;
346 t->time.tm_hour = -1;
347 t->time.tm_mday = -1;
348 t->time.tm_mon = -1;
349 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
350 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
351 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
352 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
353 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
354 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
355 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
356 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
357 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
358 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
359 t->time.tm_year = -1;
360 t->time.tm_wday = -1;
361 t->time.tm_yday = -1;
362 t->time.tm_isdst = -1;
363 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
364 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
365 return 0;
366 }
367
368 static struct rtc_class_ops m41t80_rtc_ops = {
369 .read_time = m41t80_rtc_read_time,
370 .set_time = m41t80_rtc_set_time,
371 .read_alarm = m41t80_rtc_read_alarm,
372 .set_alarm = m41t80_rtc_set_alarm,
373 .proc = m41t80_rtc_proc,
374 .ioctl = m41t80_rtc_ioctl,
375 };
376
377 #if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
378 static ssize_t m41t80_sysfs_show_flags(struct device *dev,
379 struct device_attribute *attr, char *buf)
380 {
381 struct i2c_client *client = to_i2c_client(dev);
382 int val;
383
384 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
385 if (val < 0)
386 return -EIO;
387 return sprintf(buf, "%#x\n", val);
388 }
389 static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
390
391 static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
392 struct device_attribute *attr, char *buf)
393 {
394 struct i2c_client *client = to_i2c_client(dev);
395 struct m41t80_data *clientdata = i2c_get_clientdata(client);
396 int val;
397
398 if (!(clientdata->features & M41T80_FEATURE_SQ))
399 return -EINVAL;
400
401 val = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
402 if (val < 0)
403 return -EIO;
404 val = (val >> 4) & 0xf;
405 switch (val) {
406 case 0:
407 break;
408 case 1:
409 val = 32768;
410 break;
411 default:
412 val = 32768 >> val;
413 }
414 return sprintf(buf, "%d\n", val);
415 }
416 static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
417 struct device_attribute *attr,
418 const char *buf, size_t count)
419 {
420 struct i2c_client *client = to_i2c_client(dev);
421 struct m41t80_data *clientdata = i2c_get_clientdata(client);
422 int almon, sqw;
423 int val = simple_strtoul(buf, NULL, 0);
424
425 if (!(clientdata->features & M41T80_FEATURE_SQ))
426 return -EINVAL;
427
428 if (val) {
429 if (!is_power_of_2(val))
430 return -EINVAL;
431 val = ilog2(val);
432 if (val == 15)
433 val = 1;
434 else if (val < 14)
435 val = 15 - val;
436 else
437 return -EINVAL;
438 }
439 /* disable SQW, set SQW frequency & re-enable */
440 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
441 if (almon < 0)
442 return -EIO;
443 sqw = i2c_smbus_read_byte_data(client, M41T80_REG_SQW);
444 if (sqw < 0)
445 return -EIO;
446 sqw = (sqw & 0x0f) | (val << 4);
447 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
448 almon & ~M41T80_ALMON_SQWE) < 0 ||
449 i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)
450 return -EIO;
451 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
452 almon | M41T80_ALMON_SQWE) < 0)
453 return -EIO;
454 return count;
455 }
456 static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
457 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
458
459 static struct attribute *attrs[] = {
460 &dev_attr_flags.attr,
461 &dev_attr_sqwfreq.attr,
462 NULL,
463 };
464 static struct attribute_group attr_group = {
465 .attrs = attrs,
466 };
467
468 static int m41t80_sysfs_register(struct device *dev)
469 {
470 return sysfs_create_group(&dev->kobj, &attr_group);
471 }
472 #else
473 static int m41t80_sysfs_register(struct device *dev)
474 {
475 return 0;
476 }
477 #endif
478
479 #ifdef CONFIG_RTC_DRV_M41T80_WDT
480 /*
481 *****************************************************************************
482 *
483 * Watchdog Driver
484 *
485 *****************************************************************************
486 */
487 static struct i2c_client *save_client;
488
489 /* Default margin */
490 #define WD_TIMO 60 /* 1..31 seconds */
491
492 static int wdt_margin = WD_TIMO;
493 module_param(wdt_margin, int, 0);
494 MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
495
496 static unsigned long wdt_is_open;
497 static int boot_flag;
498
499 /**
500 * wdt_ping:
501 *
502 * Reload counter one with the watchdog timeout. We don't bother reloading
503 * the cascade counter.
504 */
505 static void wdt_ping(void)
506 {
507 unsigned char i2c_data[2];
508 struct i2c_msg msgs1[1] = {
509 {
510 .addr = save_client->addr,
511 .flags = 0,
512 .len = 2,
513 .buf = i2c_data,
514 },
515 };
516 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
517
518 i2c_data[0] = 0x09; /* watchdog register */
519
520 if (wdt_margin > 31)
521 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
522 else
523 /*
524 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
525 */
526 i2c_data[1] = wdt_margin<<2 | 0x82;
527
528 /*
529 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
530 * that would be an invalid resolution.
531 */
532 if (clientdata->features & M41T80_FEATURE_WD)
533 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
534
535 i2c_transfer(save_client->adapter, msgs1, 1);
536 }
537
538 /**
539 * wdt_disable:
540 *
541 * disables watchdog.
542 */
543 static void wdt_disable(void)
544 {
545 unsigned char i2c_data[2], i2c_buf[0x10];
546 struct i2c_msg msgs0[2] = {
547 {
548 .addr = save_client->addr,
549 .flags = 0,
550 .len = 1,
551 .buf = i2c_data,
552 },
553 {
554 .addr = save_client->addr,
555 .flags = I2C_M_RD,
556 .len = 1,
557 .buf = i2c_buf,
558 },
559 };
560 struct i2c_msg msgs1[1] = {
561 {
562 .addr = save_client->addr,
563 .flags = 0,
564 .len = 2,
565 .buf = i2c_data,
566 },
567 };
568
569 i2c_data[0] = 0x09;
570 i2c_transfer(save_client->adapter, msgs0, 2);
571
572 i2c_data[0] = 0x09;
573 i2c_data[1] = 0x00;
574 i2c_transfer(save_client->adapter, msgs1, 1);
575 }
576
577 /**
578 * wdt_write:
579 * @file: file handle to the watchdog
580 * @buf: buffer to write (unused as data does not matter here
581 * @count: count of bytes
582 * @ppos: pointer to the position to write. No seeks allowed
583 *
584 * A write to a watchdog device is defined as a keepalive signal. Any
585 * write of data will do, as we we don't define content meaning.
586 */
587 static ssize_t wdt_write(struct file *file, const char __user *buf,
588 size_t count, loff_t *ppos)
589 {
590 /* Can't seek (pwrite) on this device
591 if (ppos != &file->f_pos)
592 return -ESPIPE;
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 inode *inode, 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 /**
672 * wdt_open:
673 * @inode: inode of device
674 * @file: file handle to device
675 *
676 */
677 static int wdt_open(struct inode *inode, struct file *file)
678 {
679 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
680 lock_kernel();
681 if (test_and_set_bit(0, &wdt_is_open)) {
682 unlock_kernel();
683 return -EBUSY;
684 }
685 /*
686 * Activate
687 */
688 wdt_is_open = 1;
689 unlock_kernel();
690 return 0;
691 }
692 return -ENODEV;
693 }
694
695 /**
696 * wdt_close:
697 * @inode: inode to board
698 * @file: file handle to board
699 *
700 */
701 static int wdt_release(struct inode *inode, struct file *file)
702 {
703 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
704 clear_bit(0, &wdt_is_open);
705 return 0;
706 }
707
708 /**
709 * notify_sys:
710 * @this: our notifier block
711 * @code: the event being reported
712 * @unused: unused
713 *
714 * Our notifier is called on system shutdowns. We want to turn the card
715 * off at reboot otherwise the machine will reboot again during memory
716 * test or worse yet during the following fsck. This would suck, in fact
717 * trust me - if it happens it does suck.
718 */
719 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
720 void *unused)
721 {
722 if (code == SYS_DOWN || code == SYS_HALT)
723 /* Disable Watchdog */
724 wdt_disable();
725 return NOTIFY_DONE;
726 }
727
728 static const struct file_operations wdt_fops = {
729 .owner = THIS_MODULE,
730 .read = wdt_read,
731 .ioctl = wdt_ioctl,
732 .write = wdt_write,
733 .open = wdt_open,
734 .release = wdt_release,
735 };
736
737 static struct miscdevice wdt_dev = {
738 .minor = WATCHDOG_MINOR,
739 .name = "watchdog",
740 .fops = &wdt_fops,
741 };
742
743 /*
744 * The WDT card needs to learn about soft shutdowns in order to
745 * turn the timebomb registers off.
746 */
747 static struct notifier_block wdt_notifier = {
748 .notifier_call = wdt_notify_sys,
749 };
750 #endif /* CONFIG_RTC_DRV_M41T80_WDT */
751
752 /*
753 *****************************************************************************
754 *
755 * Driver Interface
756 *
757 *****************************************************************************
758 */
759 static int m41t80_probe(struct i2c_client *client,
760 const struct i2c_device_id *id)
761 {
762 int rc = 0;
763 struct rtc_device *rtc = NULL;
764 struct rtc_time tm;
765 struct m41t80_data *clientdata = NULL;
766
767 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
768 | I2C_FUNC_SMBUS_BYTE_DATA)) {
769 rc = -ENODEV;
770 goto exit;
771 }
772
773 dev_info(&client->dev,
774 "chip found, driver version " DRV_VERSION "\n");
775
776 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
777 if (!clientdata) {
778 rc = -ENOMEM;
779 goto exit;
780 }
781
782 rtc = rtc_device_register(client->name, &client->dev,
783 &m41t80_rtc_ops, THIS_MODULE);
784 if (IS_ERR(rtc)) {
785 rc = PTR_ERR(rtc);
786 rtc = NULL;
787 goto exit;
788 }
789
790 clientdata->rtc = rtc;
791 clientdata->features = id->driver_data;
792 i2c_set_clientdata(client, clientdata);
793
794 /* Make sure HT (Halt Update) bit is cleared */
795 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
796 if (rc < 0)
797 goto ht_err;
798
799 if (rc & M41T80_ALHOUR_HT) {
800 if (clientdata->features & M41T80_FEATURE_HT) {
801 m41t80_get_datetime(client, &tm);
802 dev_info(&client->dev, "HT bit was set!\n");
803 dev_info(&client->dev,
804 "Power Down at "
805 "%04i-%02i-%02i %02i:%02i:%02i\n",
806 tm.tm_year + 1900,
807 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
808 tm.tm_min, tm.tm_sec);
809 }
810 if (i2c_smbus_write_byte_data(client,
811 M41T80_REG_ALARM_HOUR,
812 rc & ~M41T80_ALHOUR_HT) < 0)
813 goto ht_err;
814 }
815
816 /* Make sure ST (stop) bit is cleared */
817 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
818 if (rc < 0)
819 goto st_err;
820
821 if (rc & M41T80_SEC_ST) {
822 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
823 rc & ~M41T80_SEC_ST) < 0)
824 goto st_err;
825 }
826
827 rc = m41t80_sysfs_register(&client->dev);
828 if (rc)
829 goto exit;
830
831 #ifdef CONFIG_RTC_DRV_M41T80_WDT
832 if (clientdata->features & M41T80_FEATURE_HT) {
833 save_client = client;
834 rc = misc_register(&wdt_dev);
835 if (rc)
836 goto exit;
837 rc = register_reboot_notifier(&wdt_notifier);
838 if (rc) {
839 misc_deregister(&wdt_dev);
840 goto exit;
841 }
842 }
843 #endif
844 return 0;
845
846 st_err:
847 rc = -EIO;
848 dev_err(&client->dev, "Can't clear ST bit\n");
849 goto exit;
850 ht_err:
851 rc = -EIO;
852 dev_err(&client->dev, "Can't clear HT bit\n");
853 goto exit;
854
855 exit:
856 if (rtc)
857 rtc_device_unregister(rtc);
858 kfree(clientdata);
859 return rc;
860 }
861
862 static int m41t80_remove(struct i2c_client *client)
863 {
864 struct m41t80_data *clientdata = i2c_get_clientdata(client);
865 struct rtc_device *rtc = clientdata->rtc;
866
867 #ifdef CONFIG_RTC_DRV_M41T80_WDT
868 if (clientdata->features & M41T80_FEATURE_HT) {
869 misc_deregister(&wdt_dev);
870 unregister_reboot_notifier(&wdt_notifier);
871 }
872 #endif
873 if (rtc)
874 rtc_device_unregister(rtc);
875 kfree(clientdata);
876
877 return 0;
878 }
879
880 static struct i2c_driver m41t80_driver = {
881 .driver = {
882 .name = "rtc-m41t80",
883 },
884 .probe = m41t80_probe,
885 .remove = m41t80_remove,
886 .id_table = m41t80_id,
887 };
888
889 static int __init m41t80_rtc_init(void)
890 {
891 return i2c_add_driver(&m41t80_driver);
892 }
893
894 static void __exit m41t80_rtc_exit(void)
895 {
896 i2c_del_driver(&m41t80_driver);
897 }
898
899 MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
900 MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
901 MODULE_LICENSE("GPL");
902 MODULE_VERSION(DRV_VERSION);
903
904 module_init(m41t80_rtc_init);
905 module_exit(m41t80_rtc_exit);
Support for the Chinese Samsung S3C2440 based development boards