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1/*
2 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
3 *
4 * Author: Alexander Bigga <ab@mycable.de>
5 *
6 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
7 *
8 * 2006 (c) mycable GmbH
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 *
14 */
15
16#include <linux/bcd.h>
17#include <linux/i2c.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/rtc.h>
22#include <linux/slab.h>
23#include <linux/mutex.h>
24#include <linux/string.h>
25#ifdef CONFIG_RTC_DRV_M41T80_WDT
26#include <linux/fs.h>
27#include <linux/ioctl.h>
28#include <linux/miscdevice.h>
29#include <linux/reboot.h>
30#include <linux/watchdog.h>
31#endif
32
33#define M41T80_REG_SSEC 0
34#define M41T80_REG_SEC 1
35#define M41T80_REG_MIN 2
36#define M41T80_REG_HOUR 3
37#define M41T80_REG_WDAY 4
38#define M41T80_REG_DAY 5
39#define M41T80_REG_MON 6
40#define M41T80_REG_YEAR 7
41#define M41T80_REG_ALARM_MON 0xa
42#define M41T80_REG_ALARM_DAY 0xb
43#define M41T80_REG_ALARM_HOUR 0xc
44#define M41T80_REG_ALARM_MIN 0xd
45#define M41T80_REG_ALARM_SEC 0xe
46#define M41T80_REG_FLAGS 0xf
47#define M41T80_REG_SQW 0x13
48
49#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
50#define M41T80_ALARM_REG_SIZE \
51 (M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
52
53#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
54#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
55#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
56#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
57#define M41T80_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
58#define M41T80_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
59#define M41T80_WATCHDOG_RB2 (1 << 7) /* RB: Watchdog resolution */
60#define M41T80_WATCHDOG_RB1 (1 << 1) /* RB: Watchdog resolution */
61#define M41T80_WATCHDOG_RB0 (1 << 0) /* RB: Watchdog resolution */
62
63#define M41T80_FEATURE_HT (1 << 0) /* Halt feature */
64#define M41T80_FEATURE_BL (1 << 1) /* Battery low indicator */
65#define M41T80_FEATURE_SQ (1 << 2) /* Squarewave feature */
66#define M41T80_FEATURE_WD (1 << 3) /* Extra watchdog resolution */
67#define M41T80_FEATURE_SQ_ALT (1 << 4) /* RSx bits are in reg 4 */
68
69#define DRV_VERSION "0.05"
70
71static DEFINE_MUTEX(m41t80_rtc_mutex);
72static const struct i2c_device_id m41t80_id[] = {
73 { "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
74 { "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
75 { "m41t80", M41T80_FEATURE_SQ },
76 { "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
77 { "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
78 { "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
79 { "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
80 { "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
81 { "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
82 { "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
83 { }
84};
85MODULE_DEVICE_TABLE(i2c, m41t80_id);
86
87struct m41t80_data {
88 u8 features;
89 struct rtc_device *rtc;
90};
91
92static int m41t80_get_datetime(struct i2c_client *client,
93 struct rtc_time *tm)
94{
95 u8 buf[M41T80_DATETIME_REG_SIZE], dt_addr[1] = { M41T80_REG_SEC };
96 struct i2c_msg msgs[] = {
97 {
98 .addr = client->addr,
99 .flags = 0,
100 .len = 1,
101 .buf = dt_addr,
102 },
103 {
104 .addr = client->addr,
105 .flags = I2C_M_RD,
106 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
107 .buf = buf + M41T80_REG_SEC,
108 },
109 };
110
111 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
112 dev_err(&client->dev, "read error\n");
113 return -EIO;
114 }
115
116 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
117 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
118 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
119 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
120 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
121 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
122
123 /* assume 20YY not 19YY, and ignore the Century Bit */
124 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
125 return rtc_valid_tm(tm);
126}
127
128/* Sets the given date and time to the real time clock. */
129static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
130{
131 u8 wbuf[1 + M41T80_DATETIME_REG_SIZE];
132 u8 *buf = &wbuf[1];
133 u8 dt_addr[1] = { M41T80_REG_SEC };
134 struct i2c_msg msgs_in[] = {
135 {
136 .addr = client->addr,
137 .flags = 0,
138 .len = 1,
139 .buf = dt_addr,
140 },
141 {
142 .addr = client->addr,
143 .flags = I2C_M_RD,
144 .len = M41T80_DATETIME_REG_SIZE - M41T80_REG_SEC,
145 .buf = buf + M41T80_REG_SEC,
146 },
147 };
148 struct i2c_msg msgs[] = {
149 {
150 .addr = client->addr,
151 .flags = 0,
152 .len = 1 + M41T80_DATETIME_REG_SIZE,
153 .buf = wbuf,
154 },
155 };
156
157 /* Read current reg values into buf[1..7] */
158 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
159 dev_err(&client->dev, "read error\n");
160 return -EIO;
161 }
162
163 wbuf[0] = 0; /* offset into rtc's regs */
164 /* Merge time-data and register flags into buf[0..7] */
165 buf[M41T80_REG_SSEC] = 0;
166 buf[M41T80_REG_SEC] =
167 bin2bcd(tm->tm_sec) | (buf[M41T80_REG_SEC] & ~0x7f);
168 buf[M41T80_REG_MIN] =
169 bin2bcd(tm->tm_min) | (buf[M41T80_REG_MIN] & ~0x7f);
170 buf[M41T80_REG_HOUR] =
171 bin2bcd(tm->tm_hour) | (buf[M41T80_REG_HOUR] & ~0x3f) ;
172 buf[M41T80_REG_WDAY] =
173 (tm->tm_wday & 0x07) | (buf[M41T80_REG_WDAY] & ~0x07);
174 buf[M41T80_REG_DAY] =
175 bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
176 buf[M41T80_REG_MON] =
177 bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
178 /* assume 20YY not 19YY */
179 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);
180
181 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
182 dev_err(&client->dev, "write error\n");
183 return -EIO;
184 }
185 return 0;
186}
187
188#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
189static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
190{
191 struct i2c_client *client = to_i2c_client(dev);
192 struct m41t80_data *clientdata = i2c_get_clientdata(client);
193 u8 reg;
194
195 if (clientdata->features & M41T80_FEATURE_BL) {
196 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
197 seq_printf(seq, "battery\t\t: %s\n",
198 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
199 }
200 return 0;
201}
202#else
203#define m41t80_rtc_proc NULL
204#endif
205
206static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
207{
208 return m41t80_get_datetime(to_i2c_client(dev), tm);
209}
210
211static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
212{
213 return m41t80_set_datetime(to_i2c_client(dev), tm);
214}
215
216static int m41t80_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
217{
218 struct i2c_client *client = to_i2c_client(dev);
219 int rc;
220
221 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
222 if (rc < 0)
223 goto err;
224
225 if (enabled)
226 rc |= M41T80_ALMON_AFE;
227 else
228 rc &= ~M41T80_ALMON_AFE;
229
230 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, rc) < 0)
231 goto err;
232
233 return 0;
234err:
235 return -EIO;
236}
237
238static int m41t80_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
239{
240 struct i2c_client *client = to_i2c_client(dev);
241 u8 wbuf[1 + M41T80_ALARM_REG_SIZE];
242 u8 *buf = &wbuf[1];
243 u8 *reg = buf - M41T80_REG_ALARM_MON;
244 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
245 struct i2c_msg msgs_in[] = {
246 {
247 .addr = client->addr,
248 .flags = 0,
249 .len = 1,
250 .buf = dt_addr,
251 },
252 {
253 .addr = client->addr,
254 .flags = I2C_M_RD,
255 .len = M41T80_ALARM_REG_SIZE,
256 .buf = buf,
257 },
258 };
259 struct i2c_msg msgs[] = {
260 {
261 .addr = client->addr,
262 .flags = 0,
263 .len = 1 + M41T80_ALARM_REG_SIZE,
264 .buf = wbuf,
265 },
266 };
267
268 if (i2c_transfer(client->adapter, msgs_in, 2) < 0) {
269 dev_err(&client->dev, "read error\n");
270 return -EIO;
271 }
272 reg[M41T80_REG_ALARM_MON] &= ~(0x1f | M41T80_ALMON_AFE);
273 reg[M41T80_REG_ALARM_DAY] = 0;
274 reg[M41T80_REG_ALARM_HOUR] &= ~(0x3f | 0x80);
275 reg[M41T80_REG_ALARM_MIN] = 0;
276 reg[M41T80_REG_ALARM_SEC] = 0;
277
278 wbuf[0] = M41T80_REG_ALARM_MON; /* offset into rtc's regs */
279 reg[M41T80_REG_ALARM_SEC] |= t->time.tm_sec >= 0 ?
280 bin2bcd(t->time.tm_sec) : 0x80;
281 reg[M41T80_REG_ALARM_MIN] |= t->time.tm_min >= 0 ?
282 bin2bcd(t->time.tm_min) : 0x80;
283 reg[M41T80_REG_ALARM_HOUR] |= t->time.tm_hour >= 0 ?
284 bin2bcd(t->time.tm_hour) : 0x80;
285 reg[M41T80_REG_ALARM_DAY] |= t->time.tm_mday >= 0 ?
286 bin2bcd(t->time.tm_mday) : 0x80;
287 if (t->time.tm_mon >= 0)
288 reg[M41T80_REG_ALARM_MON] |= bin2bcd(t->time.tm_mon + 1);
289 else
290 reg[M41T80_REG_ALARM_DAY] |= 0x40;
291
292 if (i2c_transfer(client->adapter, msgs, 1) != 1) {
293 dev_err(&client->dev, "write error\n");
294 return -EIO;
295 }
296
297 if (t->enabled) {
298 reg[M41T80_REG_ALARM_MON] |= M41T80_ALMON_AFE;
299 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
300 reg[M41T80_REG_ALARM_MON]) < 0) {
301 dev_err(&client->dev, "write error\n");
302 return -EIO;
303 }
304 }
305 return 0;
306}
307
308static int m41t80_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *t)
309{
310 struct i2c_client *client = to_i2c_client(dev);
311 u8 buf[M41T80_ALARM_REG_SIZE + 1]; /* all alarm regs and flags */
312 u8 dt_addr[1] = { M41T80_REG_ALARM_MON };
313 u8 *reg = buf - M41T80_REG_ALARM_MON;
314 struct i2c_msg msgs[] = {
315 {
316 .addr = client->addr,
317 .flags = 0,
318 .len = 1,
319 .buf = dt_addr,
320 },
321 {
322 .addr = client->addr,
323 .flags = I2C_M_RD,
324 .len = M41T80_ALARM_REG_SIZE + 1,
325 .buf = buf,
326 },
327 };
328
329 if (i2c_transfer(client->adapter, msgs, 2) < 0) {
330 dev_err(&client->dev, "read error\n");
331 return -EIO;
332 }
333 t->time.tm_sec = -1;
334 t->time.tm_min = -1;
335 t->time.tm_hour = -1;
336 t->time.tm_mday = -1;
337 t->time.tm_mon = -1;
338 if (!(reg[M41T80_REG_ALARM_SEC] & 0x80))
339 t->time.tm_sec = bcd2bin(reg[M41T80_REG_ALARM_SEC] & 0x7f);
340 if (!(reg[M41T80_REG_ALARM_MIN] & 0x80))
341 t->time.tm_min = bcd2bin(reg[M41T80_REG_ALARM_MIN] & 0x7f);
342 if (!(reg[M41T80_REG_ALARM_HOUR] & 0x80))
343 t->time.tm_hour = bcd2bin(reg[M41T80_REG_ALARM_HOUR] & 0x3f);
344 if (!(reg[M41T80_REG_ALARM_DAY] & 0x80))
345 t->time.tm_mday = bcd2bin(reg[M41T80_REG_ALARM_DAY] & 0x3f);
346 if (!(reg[M41T80_REG_ALARM_DAY] & 0x40))
347 t->time.tm_mon = bcd2bin(reg[M41T80_REG_ALARM_MON] & 0x1f) - 1;
348 t->time.tm_year = -1;
349 t->time.tm_wday = -1;
350 t->time.tm_yday = -1;
351 t->time.tm_isdst = -1;
352 t->enabled = !!(reg[M41T80_REG_ALARM_MON] & M41T80_ALMON_AFE);
353 t->pending = !!(reg[M41T80_REG_FLAGS] & M41T80_FLAGS_AF);
354 return 0;
355}
356
357static struct rtc_class_ops m41t80_rtc_ops = {
358 .read_time = m41t80_rtc_read_time,
359 .set_time = m41t80_rtc_set_time,
360 .read_alarm = m41t80_rtc_read_alarm,
361 .set_alarm = m41t80_rtc_set_alarm,
362 .proc = m41t80_rtc_proc,
363 .alarm_irq_enable = m41t80_rtc_alarm_irq_enable,
364};
365
366#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
367static ssize_t m41t80_sysfs_show_flags(struct device *dev,
368 struct device_attribute *attr, char *buf)
369{
370 struct i2c_client *client = to_i2c_client(dev);
371 int val;
372
373 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
374 if (val < 0)
375 return -EIO;
376 return sprintf(buf, "%#x\n", val);
377}
378static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
379
380static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
381 struct device_attribute *attr, char *buf)
382{
383 struct i2c_client *client = to_i2c_client(dev);
384 struct m41t80_data *clientdata = i2c_get_clientdata(client);
385 int val, reg_sqw;
386
387 if (!(clientdata->features & M41T80_FEATURE_SQ))
388 return -EINVAL;
389
390 reg_sqw = M41T80_REG_SQW;
391 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
392 reg_sqw = M41T80_REG_WDAY;
393 val = i2c_smbus_read_byte_data(client, reg_sqw);
394 if (val < 0)
395 return -EIO;
396 val = (val >> 4) & 0xf;
397 switch (val) {
398 case 0:
399 break;
400 case 1:
401 val = 32768;
402 break;
403 default:
404 val = 32768 >> val;
405 }
406 return sprintf(buf, "%d\n", val);
407}
408static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
409 struct device_attribute *attr,
410 const char *buf, size_t count)
411{
412 struct i2c_client *client = to_i2c_client(dev);
413 struct m41t80_data *clientdata = i2c_get_clientdata(client);
414 int almon, sqw, reg_sqw;
415 int val = simple_strtoul(buf, NULL, 0);
416
417 if (!(clientdata->features & M41T80_FEATURE_SQ))
418 return -EINVAL;
419
420 if (val) {
421 if (!is_power_of_2(val))
422 return -EINVAL;
423 val = ilog2(val);
424 if (val == 15)
425 val = 1;
426 else if (val < 14)
427 val = 15 - val;
428 else
429 return -EINVAL;
430 }
431 /* disable SQW, set SQW frequency & re-enable */
432 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
433 if (almon < 0)
434 return -EIO;
435 reg_sqw = M41T80_REG_SQW;
436 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
437 reg_sqw = M41T80_REG_WDAY;
438 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
439 if (sqw < 0)
440 return -EIO;
441 sqw = (sqw & 0x0f) | (val << 4);
442 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
443 almon & ~M41T80_ALMON_SQWE) < 0 ||
444 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
445 return -EIO;
446 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
447 almon | M41T80_ALMON_SQWE) < 0)
448 return -EIO;
449 return count;
450}
451static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
452 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
453
454static struct attribute *attrs[] = {
455 &dev_attr_flags.attr,
456 &dev_attr_sqwfreq.attr,
457 NULL,
458};
459static struct attribute_group attr_group = {
460 .attrs = attrs,
461};
462
463static int m41t80_sysfs_register(struct device *dev)
464{
465 return sysfs_create_group(&dev->kobj, &attr_group);
466}
467#else
468static int m41t80_sysfs_register(struct device *dev)
469{
470 return 0;
471}
472#endif
473
474#ifdef CONFIG_RTC_DRV_M41T80_WDT
475/*
476 *****************************************************************************
477 *
478 * Watchdog Driver
479 *
480 *****************************************************************************
481 */
482static struct i2c_client *save_client;
483
484/* Default margin */
485#define WD_TIMO 60 /* 1..31 seconds */
486
487static int wdt_margin = WD_TIMO;
488module_param(wdt_margin, int, 0);
489MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
490
491static unsigned long wdt_is_open;
492static int boot_flag;
493
494/**
495 * wdt_ping:
496 *
497 * Reload counter one with the watchdog timeout. We don't bother reloading
498 * the cascade counter.
499 */
500static void wdt_ping(void)
501{
502 unsigned char i2c_data[2];
503 struct i2c_msg msgs1[1] = {
504 {
505 .addr = save_client->addr,
506 .flags = 0,
507 .len = 2,
508 .buf = i2c_data,
509 },
510 };
511 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
512
513 i2c_data[0] = 0x09; /* watchdog register */
514
515 if (wdt_margin > 31)
516 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
517 else
518 /*
519 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
520 */
521 i2c_data[1] = wdt_margin<<2 | 0x82;
522
523 /*
524 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
525 * that would be an invalid resolution.
526 */
527 if (clientdata->features & M41T80_FEATURE_WD)
528 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
529
530 i2c_transfer(save_client->adapter, msgs1, 1);
531}
532
533/**
534 * wdt_disable:
535 *
536 * disables watchdog.
537 */
538static void wdt_disable(void)
539{
540 unsigned char i2c_data[2], i2c_buf[0x10];
541 struct i2c_msg msgs0[2] = {
542 {
543 .addr = save_client->addr,
544 .flags = 0,
545 .len = 1,
546 .buf = i2c_data,
547 },
548 {
549 .addr = save_client->addr,
550 .flags = I2C_M_RD,
551 .len = 1,
552 .buf = i2c_buf,
553 },
554 };
555 struct i2c_msg msgs1[1] = {
556 {
557 .addr = save_client->addr,
558 .flags = 0,
559 .len = 2,
560 .buf = i2c_data,
561 },
562 };
563
564 i2c_data[0] = 0x09;
565 i2c_transfer(save_client->adapter, msgs0, 2);
566
567 i2c_data[0] = 0x09;
568 i2c_data[1] = 0x00;
569 i2c_transfer(save_client->adapter, msgs1, 1);
570}
571
572/**
573 * wdt_write:
574 * @file: file handle to the watchdog
575 * @buf: buffer to write (unused as data does not matter here
576 * @count: count of bytes
577 * @ppos: pointer to the position to write. No seeks allowed
578 *
579 * A write to a watchdog device is defined as a keepalive signal. Any
580 * write of data will do, as we we don't define content meaning.
581 */
582static ssize_t wdt_write(struct file *file, const char __user *buf,
583 size_t count, loff_t *ppos)
584{
585 if (count) {
586 wdt_ping();
587 return 1;
588 }
589 return 0;
590}
591
592static ssize_t wdt_read(struct file *file, char __user *buf,
593 size_t count, loff_t *ppos)
594{
595 return 0;
596}
597
598/**
599 * wdt_ioctl:
600 * @inode: inode of the device
601 * @file: file handle to the device
602 * @cmd: watchdog command
603 * @arg: argument pointer
604 *
605 * The watchdog API defines a common set of functions for all watchdogs
606 * according to their available features. We only actually usefully support
607 * querying capabilities and current status.
608 */
609static int wdt_ioctl(struct file *file, unsigned int cmd,
610 unsigned long arg)
611{
612 int new_margin, rv;
613 static struct watchdog_info ident = {
614 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
615 WDIOF_SETTIMEOUT,
616 .firmware_version = 1,
617 .identity = "M41T80 WTD"
618 };
619
620 switch (cmd) {
621 case WDIOC_GETSUPPORT:
622 return copy_to_user((struct watchdog_info __user *)arg, &ident,
623 sizeof(ident)) ? -EFAULT : 0;
624
625 case WDIOC_GETSTATUS:
626 case WDIOC_GETBOOTSTATUS:
627 return put_user(boot_flag, (int __user *)arg);
628 case WDIOC_KEEPALIVE:
629 wdt_ping();
630 return 0;
631 case WDIOC_SETTIMEOUT:
632 if (get_user(new_margin, (int __user *)arg))
633 return -EFAULT;
634 /* Arbitrary, can't find the card's limits */
635 if (new_margin < 1 || new_margin > 124)
636 return -EINVAL;
637 wdt_margin = new_margin;
638 wdt_ping();
639 /* Fall */
640 case WDIOC_GETTIMEOUT:
641 return put_user(wdt_margin, (int __user *)arg);
642
643 case WDIOC_SETOPTIONS:
644 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
645 return -EFAULT;
646
647 if (rv & WDIOS_DISABLECARD) {
648 pr_info("rtc-m41t80: disable watchdog\n");
649 wdt_disable();
650 }
651
652 if (rv & WDIOS_ENABLECARD) {
653 pr_info("rtc-m41t80: enable watchdog\n");
654 wdt_ping();
655 }
656
657 return -EINVAL;
658 }
659 return -ENOTTY;
660}
661
662static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
663 unsigned long arg)
664{
665 int ret;
666
667 mutex_lock(&m41t80_rtc_mutex);
668 ret = wdt_ioctl(file, cmd, arg);
669 mutex_unlock(&m41t80_rtc_mutex);
670
671 return ret;
672}
673
674/**
675 * wdt_open:
676 * @inode: inode of device
677 * @file: file handle to device
678 *
679 */
680static int wdt_open(struct inode *inode, struct file *file)
681{
682 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
683 mutex_lock(&m41t80_rtc_mutex);
684 if (test_and_set_bit(0, &wdt_is_open)) {
685 mutex_unlock(&m41t80_rtc_mutex);
686 return -EBUSY;
687 }
688 /*
689 * Activate
690 */
691 wdt_is_open = 1;
692 mutex_unlock(&m41t80_rtc_mutex);
693 return nonseekable_open(inode, file);
694 }
695 return -ENODEV;
696}
697
698/**
699 * wdt_close:
700 * @inode: inode to board
701 * @file: file handle to board
702 *
703 */
704static int wdt_release(struct inode *inode, struct file *file)
705{
706 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
707 clear_bit(0, &wdt_is_open);
708 return 0;
709}
710
711/**
712 * notify_sys:
713 * @this: our notifier block
714 * @code: the event being reported
715 * @unused: unused
716 *
717 * Our notifier is called on system shutdowns. We want to turn the card
718 * off at reboot otherwise the machine will reboot again during memory
719 * test or worse yet during the following fsck. This would suck, in fact
720 * trust me - if it happens it does suck.
721 */
722static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
723 void *unused)
724{
725 if (code == SYS_DOWN || code == SYS_HALT)
726 /* Disable Watchdog */
727 wdt_disable();
728 return NOTIFY_DONE;
729}
730
731static const struct file_operations wdt_fops = {
732 .owner = THIS_MODULE,
733 .read = wdt_read,
734 .unlocked_ioctl = wdt_unlocked_ioctl,
735 .write = wdt_write,
736 .open = wdt_open,
737 .release = wdt_release,
738 .llseek = no_llseek,
739};
740
741static struct miscdevice wdt_dev = {
742 .minor = WATCHDOG_MINOR,
743 .name = "watchdog",
744 .fops = &wdt_fops,
745};
746
747/*
748 * The WDT card needs to learn about soft shutdowns in order to
749 * turn the timebomb registers off.
750 */
751static struct notifier_block wdt_notifier = {
752 .notifier_call = wdt_notify_sys,
753};
754#endif /* CONFIG_RTC_DRV_M41T80_WDT */
755
756/*
757 *****************************************************************************
758 *
759 * Driver Interface
760 *
761 *****************************************************************************
762 */
763static int m41t80_probe(struct i2c_client *client,
764 const struct i2c_device_id *id)
765{
766 int rc = 0;
767 struct rtc_device *rtc = NULL;
768 struct rtc_time tm;
769 struct m41t80_data *clientdata = NULL;
770
771 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
772 | I2C_FUNC_SMBUS_BYTE_DATA)) {
773 rc = -ENODEV;
774 goto exit;
775 }
776
777 dev_info(&client->dev,
778 "chip found, driver version " DRV_VERSION "\n");
779
780 clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
781 if (!clientdata) {
782 rc = -ENOMEM;
783 goto exit;
784 }
785
786 clientdata->features = id->driver_data;
787 i2c_set_clientdata(client, clientdata);
788
789 rtc = rtc_device_register(client->name, &client->dev,
790 &m41t80_rtc_ops, THIS_MODULE);
791 if (IS_ERR(rtc)) {
792 rc = PTR_ERR(rtc);
793 rtc = NULL;
794 goto exit;
795 }
796
797 clientdata->rtc = rtc;
798
799 /* Make sure HT (Halt Update) bit is cleared */
800 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
801 if (rc < 0)
802 goto ht_err;
803
804 if (rc & M41T80_ALHOUR_HT) {
805 if (clientdata->features & M41T80_FEATURE_HT) {
806 m41t80_get_datetime(client, &tm);
807 dev_info(&client->dev, "HT bit was set!\n");
808 dev_info(&client->dev,
809 "Power Down at "
810 "%04i-%02i-%02i %02i:%02i:%02i\n",
811 tm.tm_year + 1900,
812 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
813 tm.tm_min, tm.tm_sec);
814 }
815 if (i2c_smbus_write_byte_data(client,
816 M41T80_REG_ALARM_HOUR,
817 rc & ~M41T80_ALHOUR_HT) < 0)
818 goto ht_err;
819 }
820
821 /* Make sure ST (stop) bit is cleared */
822 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
823 if (rc < 0)
824 goto st_err;
825
826 if (rc & M41T80_SEC_ST) {
827 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
828 rc & ~M41T80_SEC_ST) < 0)
829 goto st_err;
830 }
831
832 rc = m41t80_sysfs_register(&client->dev);
833 if (rc)
834 goto exit;
835
836#ifdef CONFIG_RTC_DRV_M41T80_WDT
837 if (clientdata->features & M41T80_FEATURE_HT) {
838 save_client = client;
839 rc = misc_register(&wdt_dev);
840 if (rc)
841 goto exit;
842 rc = register_reboot_notifier(&wdt_notifier);
843 if (rc) {
844 misc_deregister(&wdt_dev);
845 goto exit;
846 }
847 }
848#endif
849 return 0;
850
851st_err:
852 rc = -EIO;
853 dev_err(&client->dev, "Can't clear ST bit\n");
854 goto exit;
855ht_err:
856 rc = -EIO;
857 dev_err(&client->dev, "Can't clear HT bit\n");
858 goto exit;
859
860exit:
861 if (rtc)
862 rtc_device_unregister(rtc);
863 kfree(clientdata);
864 return rc;
865}
866
867static int m41t80_remove(struct i2c_client *client)
868{
869 struct m41t80_data *clientdata = i2c_get_clientdata(client);
870 struct rtc_device *rtc = clientdata->rtc;
871
872#ifdef CONFIG_RTC_DRV_M41T80_WDT
873 if (clientdata->features & M41T80_FEATURE_HT) {
874 misc_deregister(&wdt_dev);
875 unregister_reboot_notifier(&wdt_notifier);
876 }
877#endif
878 if (rtc)
879 rtc_device_unregister(rtc);
880 kfree(clientdata);
881
882 return 0;
883}
884
885static struct i2c_driver m41t80_driver = {
886 .driver = {
887 .name = "rtc-m41t80",
888 },
889 .probe = m41t80_probe,
890 .remove = m41t80_remove,
891 .id_table = m41t80_id,
892};
893
894static int __init m41t80_rtc_init(void)
895{
896 return i2c_add_driver(&m41t80_driver);
897}
898
899static void __exit m41t80_rtc_exit(void)
900{
901 i2c_del_driver(&m41t80_driver);
902}
903
904MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
905MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
906MODULE_LICENSE("GPL");
907MODULE_VERSION(DRV_VERSION);
908
909module_init(m41t80_rtc_init);
910module_exit(m41t80_rtc_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * I2C client/driver for the ST M41T80 family of i2c rtc chips.
4 *
5 * Author: Alexander Bigga <ab@mycable.de>
6 *
7 * Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
8 *
9 * 2006 (c) mycable GmbH
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/bcd.h>
15#include <linux/clk-provider.h>
16#include <linux/i2c.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/of_device.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 0x00
34#define M41T80_REG_SEC 0x01
35#define M41T80_REG_MIN 0x02
36#define M41T80_REG_HOUR 0x03
37#define M41T80_REG_WDAY 0x04
38#define M41T80_REG_DAY 0x05
39#define M41T80_REG_MON 0x06
40#define M41T80_REG_YEAR 0x07
41#define M41T80_REG_ALARM_MON 0x0a
42#define M41T80_REG_ALARM_DAY 0x0b
43#define M41T80_REG_ALARM_HOUR 0x0c
44#define M41T80_REG_ALARM_MIN 0x0d
45#define M41T80_REG_ALARM_SEC 0x0e
46#define M41T80_REG_FLAGS 0x0f
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_SQW_MAX_FREQ 32768
54
55#define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
56#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
57#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
58#define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
59#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
60#define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
61#define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
62#define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
63#define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
64#define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
65
66#define M41T80_FEATURE_HT BIT(0) /* Halt feature */
67#define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
68#define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
69#define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
70#define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
71
72static 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 { "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
84 { }
85};
86MODULE_DEVICE_TABLE(i2c, m41t80_id);
87
88static const struct of_device_id m41t80_of_match[] = {
89 {
90 .compatible = "st,m41t62",
91 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT)
92 },
93 {
94 .compatible = "st,m41t65",
95 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD)
96 },
97 {
98 .compatible = "st,m41t80",
99 .data = (void *)(M41T80_FEATURE_SQ)
100 },
101 {
102 .compatible = "st,m41t81",
103 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ)
104 },
105 {
106 .compatible = "st,m41t81s",
107 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
108 },
109 {
110 .compatible = "st,m41t82",
111 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
112 },
113 {
114 .compatible = "st,m41t83",
115 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
116 },
117 {
118 .compatible = "st,m41t84",
119 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
120 },
121 {
122 .compatible = "st,m41t85",
123 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
124 },
125 {
126 .compatible = "st,m41t87",
127 .data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
128 },
129 {
130 .compatible = "microcrystal,rv4162",
131 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
132 },
133 /* DT compatibility only, do not use compatibles below: */
134 {
135 .compatible = "st,rv4162",
136 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
137 },
138 {
139 .compatible = "rv4162",
140 .data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
141 },
142 { }
143};
144MODULE_DEVICE_TABLE(of, m41t80_of_match);
145
146struct m41t80_data {
147 unsigned long features;
148 struct i2c_client *client;
149 struct rtc_device *rtc;
150#ifdef CONFIG_COMMON_CLK
151 struct clk_hw sqw;
152 unsigned long freq;
153 unsigned int sqwe;
154#endif
155};
156
157static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
158{
159 struct i2c_client *client = dev_id;
160 struct m41t80_data *m41t80 = i2c_get_clientdata(client);
161 struct mutex *lock = &m41t80->rtc->ops_lock;
162 unsigned long events = 0;
163 int flags, flags_afe;
164
165 mutex_lock(lock);
166
167 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
168 if (flags_afe < 0) {
169 mutex_unlock(lock);
170 return IRQ_NONE;
171 }
172
173 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
174 if (flags <= 0) {
175 mutex_unlock(lock);
176 return IRQ_NONE;
177 }
178
179 if (flags & M41T80_FLAGS_AF) {
180 flags &= ~M41T80_FLAGS_AF;
181 flags_afe &= ~M41T80_ALMON_AFE;
182 events |= RTC_AF;
183 }
184
185 if (events) {
186 rtc_update_irq(m41t80->rtc, 1, events);
187 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
188 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
189 flags_afe);
190 }
191
192 mutex_unlock(lock);
193
194 return IRQ_HANDLED;
195}
196
197static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
198{
199 struct i2c_client *client = to_i2c_client(dev);
200 unsigned char buf[8];
201 int err, flags;
202
203 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
204 if (flags < 0)
205 return flags;
206
207 if (flags & M41T80_FLAGS_OF) {
208 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
209 return -EINVAL;
210 }
211
212 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
213 sizeof(buf), buf);
214 if (err < 0) {
215 dev_err(&client->dev, "Unable to read date\n");
216 return err;
217 }
218
219 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
220 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
221 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
222 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
223 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
224 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
225
226 /* assume 20YY not 19YY, and ignore the Century Bit */
227 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
228 return 0;
229}
230
231static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
232{
233 struct i2c_client *client = to_i2c_client(dev);
234 struct m41t80_data *clientdata = i2c_get_clientdata(client);
235 unsigned char buf[8];
236 int err, flags;
237
238 if (tm->tm_year < 100 || tm->tm_year > 199)
239 return -EINVAL;
240
241 buf[M41T80_REG_SSEC] = 0;
242 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
243 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
244 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
245 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
246 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
247 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
248 buf[M41T80_REG_WDAY] = tm->tm_wday;
249
250 /* If the square wave output is controlled in the weekday register */
251 if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
252 int val;
253
254 val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
255 if (val < 0)
256 return val;
257
258 buf[M41T80_REG_WDAY] |= (val & 0xf0);
259 }
260
261 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
262 sizeof(buf), buf);
263 if (err < 0) {
264 dev_err(&client->dev, "Unable to write to date registers\n");
265 return err;
266 }
267
268 /* Clear the OF bit of Flags Register */
269 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
270 if (flags < 0)
271 return flags;
272
273 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
274 flags & ~M41T80_FLAGS_OF);
275 if (err < 0) {
276 dev_err(&client->dev, "Unable to write flags register\n");
277 return err;
278 }
279
280 return err;
281}
282
283static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
284{
285 struct i2c_client *client = to_i2c_client(dev);
286 struct m41t80_data *clientdata = i2c_get_clientdata(client);
287 int reg;
288
289 if (clientdata->features & M41T80_FEATURE_BL) {
290 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
291 if (reg < 0)
292 return reg;
293 seq_printf(seq, "battery\t\t: %s\n",
294 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
295 }
296 return 0;
297}
298
299static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
300{
301 struct i2c_client *client = to_i2c_client(dev);
302 int flags, retval;
303
304 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
305 if (flags < 0)
306 return flags;
307
308 if (enabled)
309 flags |= M41T80_ALMON_AFE;
310 else
311 flags &= ~M41T80_ALMON_AFE;
312
313 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
314 if (retval < 0) {
315 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
316 return retval;
317 }
318 return 0;
319}
320
321static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
322{
323 struct i2c_client *client = to_i2c_client(dev);
324 u8 alarmvals[5];
325 int ret, err;
326
327 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
328 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
329 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
330 alarmvals[3] = bin2bcd(alrm->time.tm_min);
331 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
332
333 /* Clear AF and AFE flags */
334 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
335 if (ret < 0)
336 return ret;
337 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
338 ret & ~(M41T80_ALMON_AFE));
339 if (err < 0) {
340 dev_err(dev, "Unable to clear AFE bit\n");
341 return err;
342 }
343
344 /* Keep SQWE bit value */
345 alarmvals[0] |= (ret & M41T80_ALMON_SQWE);
346
347 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
348 if (ret < 0)
349 return ret;
350
351 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
352 ret & ~(M41T80_FLAGS_AF));
353 if (err < 0) {
354 dev_err(dev, "Unable to clear AF bit\n");
355 return err;
356 }
357
358 /* Write the alarm */
359 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
360 5, alarmvals);
361 if (err)
362 return err;
363
364 /* Enable the alarm interrupt */
365 if (alrm->enabled) {
366 alarmvals[0] |= M41T80_ALMON_AFE;
367 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
368 alarmvals[0]);
369 if (err)
370 return err;
371 }
372
373 return 0;
374}
375
376static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
377{
378 struct i2c_client *client = to_i2c_client(dev);
379 u8 alarmvals[5];
380 int flags, ret;
381
382 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
383 5, alarmvals);
384 if (ret != 5)
385 return ret < 0 ? ret : -EIO;
386
387 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
388 if (flags < 0)
389 return flags;
390
391 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
392 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
393 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
394 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
395 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1;
396
397 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
398 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
399
400 return 0;
401}
402
403static struct rtc_class_ops m41t80_rtc_ops = {
404 .read_time = m41t80_rtc_read_time,
405 .set_time = m41t80_rtc_set_time,
406 .proc = m41t80_rtc_proc,
407};
408
409#ifdef CONFIG_PM_SLEEP
410static int m41t80_suspend(struct device *dev)
411{
412 struct i2c_client *client = to_i2c_client(dev);
413
414 if (client->irq >= 0 && device_may_wakeup(dev))
415 enable_irq_wake(client->irq);
416
417 return 0;
418}
419
420static int m41t80_resume(struct device *dev)
421{
422 struct i2c_client *client = to_i2c_client(dev);
423
424 if (client->irq >= 0 && device_may_wakeup(dev))
425 disable_irq_wake(client->irq);
426
427 return 0;
428}
429#endif
430
431static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
432
433#ifdef CONFIG_COMMON_CLK
434#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
435
436static unsigned long m41t80_decode_freq(int setting)
437{
438 return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ :
439 M41T80_SQW_MAX_FREQ >> setting;
440}
441
442static unsigned long m41t80_get_freq(struct m41t80_data *m41t80)
443{
444 struct i2c_client *client = m41t80->client;
445 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
446 M41T80_REG_WDAY : M41T80_REG_SQW;
447 int ret = i2c_smbus_read_byte_data(client, reg_sqw);
448
449 if (ret < 0)
450 return 0;
451 return m41t80_decode_freq(ret >> 4);
452}
453
454static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
455 unsigned long parent_rate)
456{
457 return sqw_to_m41t80_data(hw)->freq;
458}
459
460static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
461 unsigned long *prate)
462{
463 if (rate >= M41T80_SQW_MAX_FREQ)
464 return M41T80_SQW_MAX_FREQ;
465 if (rate >= M41T80_SQW_MAX_FREQ / 4)
466 return M41T80_SQW_MAX_FREQ / 4;
467 if (!rate)
468 return 0;
469 return 1 << ilog2(rate);
470}
471
472static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
473 unsigned long parent_rate)
474{
475 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
476 struct i2c_client *client = m41t80->client;
477 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
478 M41T80_REG_WDAY : M41T80_REG_SQW;
479 int reg, ret, val = 0;
480
481 if (rate >= M41T80_SQW_MAX_FREQ)
482 val = 1;
483 else if (rate >= M41T80_SQW_MAX_FREQ / 4)
484 val = 2;
485 else if (rate)
486 val = 15 - ilog2(rate);
487
488 reg = i2c_smbus_read_byte_data(client, reg_sqw);
489 if (reg < 0)
490 return reg;
491
492 reg = (reg & 0x0f) | (val << 4);
493
494 ret = i2c_smbus_write_byte_data(client, reg_sqw, reg);
495 if (!ret)
496 m41t80->freq = m41t80_decode_freq(val);
497 return ret;
498}
499
500static int m41t80_sqw_control(struct clk_hw *hw, bool enable)
501{
502 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
503 struct i2c_client *client = m41t80->client;
504 int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
505
506 if (ret < 0)
507 return ret;
508
509 if (enable)
510 ret |= M41T80_ALMON_SQWE;
511 else
512 ret &= ~M41T80_ALMON_SQWE;
513
514 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
515 if (!ret)
516 m41t80->sqwe = enable;
517 return ret;
518}
519
520static int m41t80_sqw_prepare(struct clk_hw *hw)
521{
522 return m41t80_sqw_control(hw, 1);
523}
524
525static void m41t80_sqw_unprepare(struct clk_hw *hw)
526{
527 m41t80_sqw_control(hw, 0);
528}
529
530static int m41t80_sqw_is_prepared(struct clk_hw *hw)
531{
532 return sqw_to_m41t80_data(hw)->sqwe;
533}
534
535static const struct clk_ops m41t80_sqw_ops = {
536 .prepare = m41t80_sqw_prepare,
537 .unprepare = m41t80_sqw_unprepare,
538 .is_prepared = m41t80_sqw_is_prepared,
539 .recalc_rate = m41t80_sqw_recalc_rate,
540 .round_rate = m41t80_sqw_round_rate,
541 .set_rate = m41t80_sqw_set_rate,
542};
543
544static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
545{
546 struct i2c_client *client = m41t80->client;
547 struct device_node *node = client->dev.of_node;
548 struct clk *clk;
549 struct clk_init_data init;
550 int ret;
551
552 /* First disable the clock */
553 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
554 if (ret < 0)
555 return ERR_PTR(ret);
556 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
557 ret & ~(M41T80_ALMON_SQWE));
558 if (ret < 0)
559 return ERR_PTR(ret);
560
561 init.name = "m41t80-sqw";
562 init.ops = &m41t80_sqw_ops;
563 init.flags = 0;
564 init.parent_names = NULL;
565 init.num_parents = 0;
566 m41t80->sqw.init = &init;
567 m41t80->freq = m41t80_get_freq(m41t80);
568
569 /* optional override of the clockname */
570 of_property_read_string(node, "clock-output-names", &init.name);
571
572 /* register the clock */
573 clk = clk_register(&client->dev, &m41t80->sqw);
574 if (!IS_ERR(clk))
575 of_clk_add_provider(node, of_clk_src_simple_get, clk);
576
577 return clk;
578}
579#endif
580
581#ifdef CONFIG_RTC_DRV_M41T80_WDT
582/*
583 *****************************************************************************
584 *
585 * Watchdog Driver
586 *
587 *****************************************************************************
588 */
589static DEFINE_MUTEX(m41t80_rtc_mutex);
590static struct i2c_client *save_client;
591
592/* Default margin */
593#define WD_TIMO 60 /* 1..31 seconds */
594
595static int wdt_margin = WD_TIMO;
596module_param(wdt_margin, int, 0);
597MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
598
599static unsigned long wdt_is_open;
600static int boot_flag;
601
602/**
603 * wdt_ping:
604 *
605 * Reload counter one with the watchdog timeout. We don't bother reloading
606 * the cascade counter.
607 */
608static void wdt_ping(void)
609{
610 unsigned char i2c_data[2];
611 struct i2c_msg msgs1[1] = {
612 {
613 .addr = save_client->addr,
614 .flags = 0,
615 .len = 2,
616 .buf = i2c_data,
617 },
618 };
619 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
620
621 i2c_data[0] = 0x09; /* watchdog register */
622
623 if (wdt_margin > 31)
624 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
625 else
626 /*
627 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
628 */
629 i2c_data[1] = wdt_margin << 2 | 0x82;
630
631 /*
632 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
633 * that would be an invalid resolution.
634 */
635 if (clientdata->features & M41T80_FEATURE_WD)
636 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
637
638 i2c_transfer(save_client->adapter, msgs1, 1);
639}
640
641/**
642 * wdt_disable:
643 *
644 * disables watchdog.
645 */
646static void wdt_disable(void)
647{
648 unsigned char i2c_data[2], i2c_buf[0x10];
649 struct i2c_msg msgs0[2] = {
650 {
651 .addr = save_client->addr,
652 .flags = 0,
653 .len = 1,
654 .buf = i2c_data,
655 },
656 {
657 .addr = save_client->addr,
658 .flags = I2C_M_RD,
659 .len = 1,
660 .buf = i2c_buf,
661 },
662 };
663 struct i2c_msg msgs1[1] = {
664 {
665 .addr = save_client->addr,
666 .flags = 0,
667 .len = 2,
668 .buf = i2c_data,
669 },
670 };
671
672 i2c_data[0] = 0x09;
673 i2c_transfer(save_client->adapter, msgs0, 2);
674
675 i2c_data[0] = 0x09;
676 i2c_data[1] = 0x00;
677 i2c_transfer(save_client->adapter, msgs1, 1);
678}
679
680/**
681 * wdt_write:
682 * @file: file handle to the watchdog
683 * @buf: buffer to write (unused as data does not matter here
684 * @count: count of bytes
685 * @ppos: pointer to the position to write. No seeks allowed
686 *
687 * A write to a watchdog device is defined as a keepalive signal. Any
688 * write of data will do, as we we don't define content meaning.
689 */
690static ssize_t wdt_write(struct file *file, const char __user *buf,
691 size_t count, loff_t *ppos)
692{
693 if (count) {
694 wdt_ping();
695 return 1;
696 }
697 return 0;
698}
699
700static ssize_t wdt_read(struct file *file, char __user *buf,
701 size_t count, loff_t *ppos)
702{
703 return 0;
704}
705
706/**
707 * wdt_ioctl:
708 * @inode: inode of the device
709 * @file: file handle to the device
710 * @cmd: watchdog command
711 * @arg: argument pointer
712 *
713 * The watchdog API defines a common set of functions for all watchdogs
714 * according to their available features. We only actually usefully support
715 * querying capabilities and current status.
716 */
717static int wdt_ioctl(struct file *file, unsigned int cmd,
718 unsigned long arg)
719{
720 int new_margin, rv;
721 static struct watchdog_info ident = {
722 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
723 WDIOF_SETTIMEOUT,
724 .firmware_version = 1,
725 .identity = "M41T80 WTD"
726 };
727
728 switch (cmd) {
729 case WDIOC_GETSUPPORT:
730 return copy_to_user((struct watchdog_info __user *)arg, &ident,
731 sizeof(ident)) ? -EFAULT : 0;
732
733 case WDIOC_GETSTATUS:
734 case WDIOC_GETBOOTSTATUS:
735 return put_user(boot_flag, (int __user *)arg);
736 case WDIOC_KEEPALIVE:
737 wdt_ping();
738 return 0;
739 case WDIOC_SETTIMEOUT:
740 if (get_user(new_margin, (int __user *)arg))
741 return -EFAULT;
742 /* Arbitrary, can't find the card's limits */
743 if (new_margin < 1 || new_margin > 124)
744 return -EINVAL;
745 wdt_margin = new_margin;
746 wdt_ping();
747 /* Fall through */
748 case WDIOC_GETTIMEOUT:
749 return put_user(wdt_margin, (int __user *)arg);
750
751 case WDIOC_SETOPTIONS:
752 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
753 return -EFAULT;
754
755 if (rv & WDIOS_DISABLECARD) {
756 pr_info("disable watchdog\n");
757 wdt_disable();
758 }
759
760 if (rv & WDIOS_ENABLECARD) {
761 pr_info("enable watchdog\n");
762 wdt_ping();
763 }
764
765 return -EINVAL;
766 }
767 return -ENOTTY;
768}
769
770static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
771 unsigned long arg)
772{
773 int ret;
774
775 mutex_lock(&m41t80_rtc_mutex);
776 ret = wdt_ioctl(file, cmd, arg);
777 mutex_unlock(&m41t80_rtc_mutex);
778
779 return ret;
780}
781
782/**
783 * wdt_open:
784 * @inode: inode of device
785 * @file: file handle to device
786 *
787 */
788static int wdt_open(struct inode *inode, struct file *file)
789{
790 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
791 mutex_lock(&m41t80_rtc_mutex);
792 if (test_and_set_bit(0, &wdt_is_open)) {
793 mutex_unlock(&m41t80_rtc_mutex);
794 return -EBUSY;
795 }
796 /*
797 * Activate
798 */
799 wdt_is_open = 1;
800 mutex_unlock(&m41t80_rtc_mutex);
801 return stream_open(inode, file);
802 }
803 return -ENODEV;
804}
805
806/**
807 * wdt_close:
808 * @inode: inode to board
809 * @file: file handle to board
810 *
811 */
812static int wdt_release(struct inode *inode, struct file *file)
813{
814 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
815 clear_bit(0, &wdt_is_open);
816 return 0;
817}
818
819/**
820 * notify_sys:
821 * @this: our notifier block
822 * @code: the event being reported
823 * @unused: unused
824 *
825 * Our notifier is called on system shutdowns. We want to turn the card
826 * off at reboot otherwise the machine will reboot again during memory
827 * test or worse yet during the following fsck. This would suck, in fact
828 * trust me - if it happens it does suck.
829 */
830static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
831 void *unused)
832{
833 if (code == SYS_DOWN || code == SYS_HALT)
834 /* Disable Watchdog */
835 wdt_disable();
836 return NOTIFY_DONE;
837}
838
839static const struct file_operations wdt_fops = {
840 .owner = THIS_MODULE,
841 .read = wdt_read,
842 .unlocked_ioctl = wdt_unlocked_ioctl,
843 .write = wdt_write,
844 .open = wdt_open,
845 .release = wdt_release,
846 .llseek = no_llseek,
847};
848
849static struct miscdevice wdt_dev = {
850 .minor = WATCHDOG_MINOR,
851 .name = "watchdog",
852 .fops = &wdt_fops,
853};
854
855/*
856 * The WDT card needs to learn about soft shutdowns in order to
857 * turn the timebomb registers off.
858 */
859static struct notifier_block wdt_notifier = {
860 .notifier_call = wdt_notify_sys,
861};
862#endif /* CONFIG_RTC_DRV_M41T80_WDT */
863
864/*
865 *****************************************************************************
866 *
867 * Driver Interface
868 *
869 *****************************************************************************
870 */
871
872static int m41t80_probe(struct i2c_client *client,
873 const struct i2c_device_id *id)
874{
875 struct i2c_adapter *adapter = client->adapter;
876 int rc = 0;
877 struct rtc_time tm;
878 struct m41t80_data *m41t80_data = NULL;
879 bool wakeup_source = false;
880
881 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
882 I2C_FUNC_SMBUS_BYTE_DATA)) {
883 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
884 return -ENODEV;
885 }
886
887 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
888 GFP_KERNEL);
889 if (!m41t80_data)
890 return -ENOMEM;
891
892 m41t80_data->client = client;
893 if (client->dev.of_node)
894 m41t80_data->features = (unsigned long)
895 of_device_get_match_data(&client->dev);
896 else
897 m41t80_data->features = id->driver_data;
898 i2c_set_clientdata(client, m41t80_data);
899
900 m41t80_data->rtc = devm_rtc_allocate_device(&client->dev);
901 if (IS_ERR(m41t80_data->rtc))
902 return PTR_ERR(m41t80_data->rtc);
903
904#ifdef CONFIG_OF
905 wakeup_source = of_property_read_bool(client->dev.of_node,
906 "wakeup-source");
907#endif
908 if (client->irq > 0) {
909 rc = devm_request_threaded_irq(&client->dev, client->irq,
910 NULL, m41t80_handle_irq,
911 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
912 "m41t80", client);
913 if (rc) {
914 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
915 client->irq = 0;
916 wakeup_source = false;
917 }
918 }
919 if (client->irq > 0 || wakeup_source) {
920 m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
921 m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
922 m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
923 /* Enable the wakealarm */
924 device_init_wakeup(&client->dev, true);
925 }
926
927 m41t80_data->rtc->ops = &m41t80_rtc_ops;
928
929 if (client->irq <= 0) {
930 /* We cannot support UIE mode if we do not have an IRQ line */
931 m41t80_data->rtc->uie_unsupported = 1;
932 }
933
934 /* Make sure HT (Halt Update) bit is cleared */
935 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
936
937 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
938 if (m41t80_data->features & M41T80_FEATURE_HT) {
939 m41t80_rtc_read_time(&client->dev, &tm);
940 dev_info(&client->dev, "HT bit was set!\n");
941 dev_info(&client->dev, "Power Down at %ptR\n", &tm);
942 }
943 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
944 rc & ~M41T80_ALHOUR_HT);
945 }
946
947 if (rc < 0) {
948 dev_err(&client->dev, "Can't clear HT bit\n");
949 return rc;
950 }
951
952 /* Make sure ST (stop) bit is cleared */
953 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
954
955 if (rc >= 0 && rc & M41T80_SEC_ST)
956 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
957 rc & ~M41T80_SEC_ST);
958 if (rc < 0) {
959 dev_err(&client->dev, "Can't clear ST bit\n");
960 return rc;
961 }
962
963#ifdef CONFIG_RTC_DRV_M41T80_WDT
964 if (m41t80_data->features & M41T80_FEATURE_HT) {
965 save_client = client;
966 rc = misc_register(&wdt_dev);
967 if (rc)
968 return rc;
969 rc = register_reboot_notifier(&wdt_notifier);
970 if (rc) {
971 misc_deregister(&wdt_dev);
972 return rc;
973 }
974 }
975#endif
976#ifdef CONFIG_COMMON_CLK
977 if (m41t80_data->features & M41T80_FEATURE_SQ)
978 m41t80_sqw_register_clk(m41t80_data);
979#endif
980
981 rc = rtc_register_device(m41t80_data->rtc);
982 if (rc)
983 return rc;
984
985 return 0;
986}
987
988static int m41t80_remove(struct i2c_client *client)
989{
990#ifdef CONFIG_RTC_DRV_M41T80_WDT
991 struct m41t80_data *clientdata = i2c_get_clientdata(client);
992
993 if (clientdata->features & M41T80_FEATURE_HT) {
994 misc_deregister(&wdt_dev);
995 unregister_reboot_notifier(&wdt_notifier);
996 }
997#endif
998
999 return 0;
1000}
1001
1002static struct i2c_driver m41t80_driver = {
1003 .driver = {
1004 .name = "rtc-m41t80",
1005 .of_match_table = of_match_ptr(m41t80_of_match),
1006 .pm = &m41t80_pm,
1007 },
1008 .probe = m41t80_probe,
1009 .remove = m41t80_remove,
1010 .id_table = m41t80_id,
1011};
1012
1013module_i2c_driver(m41t80_driver);
1014
1015MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
1016MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
1017MODULE_LICENSE("GPL");