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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.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 __maybe_unused 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 unsigned long events = 0;
162 int flags, flags_afe;
163
164 rtc_lock(m41t80->rtc);
165
166 flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
167 if (flags_afe < 0) {
168 rtc_unlock(m41t80->rtc);
169 return IRQ_NONE;
170 }
171
172 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
173 if (flags <= 0) {
174 rtc_unlock(m41t80->rtc);
175 return IRQ_NONE;
176 }
177
178 if (flags & M41T80_FLAGS_AF) {
179 flags &= ~M41T80_FLAGS_AF;
180 flags_afe &= ~M41T80_ALMON_AFE;
181 events |= RTC_AF;
182 }
183
184 if (events) {
185 rtc_update_irq(m41t80->rtc, 1, events);
186 i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
187 i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
188 flags_afe);
189 }
190
191 rtc_unlock(m41t80->rtc);
192
193 return IRQ_HANDLED;
194}
195
196static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
197{
198 struct i2c_client *client = to_i2c_client(dev);
199 unsigned char buf[8];
200 int err, flags;
201
202 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
203 if (flags < 0)
204 return flags;
205
206 if (flags & M41T80_FLAGS_OF) {
207 dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
208 return -EINVAL;
209 }
210
211 err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
212 sizeof(buf), buf);
213 if (err < 0) {
214 dev_err(&client->dev, "Unable to read date\n");
215 return err;
216 }
217
218 tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
219 tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
220 tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
221 tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
222 tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
223 tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
224
225 /* assume 20YY not 19YY, and ignore the Century Bit */
226 tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
227 return 0;
228}
229
230static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
231{
232 struct i2c_client *client = to_i2c_client(dev);
233 struct m41t80_data *clientdata = i2c_get_clientdata(client);
234 unsigned char buf[8];
235 int err, flags;
236
237 buf[M41T80_REG_SSEC] = 0;
238 buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
239 buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
240 buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
241 buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
242 buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
243 buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
244 buf[M41T80_REG_WDAY] = tm->tm_wday;
245
246 /* If the square wave output is controlled in the weekday register */
247 if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
248 int val;
249
250 val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
251 if (val < 0)
252 return val;
253
254 buf[M41T80_REG_WDAY] |= (val & 0xf0);
255 }
256
257 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
258 sizeof(buf), buf);
259 if (err < 0) {
260 dev_err(&client->dev, "Unable to write to date registers\n");
261 return err;
262 }
263
264 /* Clear the OF bit of Flags Register */
265 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
266 if (flags < 0)
267 return flags;
268
269 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
270 flags & ~M41T80_FLAGS_OF);
271 if (err < 0) {
272 dev_err(&client->dev, "Unable to write flags register\n");
273 return err;
274 }
275
276 return err;
277}
278
279static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
280{
281 struct i2c_client *client = to_i2c_client(dev);
282 struct m41t80_data *clientdata = i2c_get_clientdata(client);
283 int reg;
284
285 if (clientdata->features & M41T80_FEATURE_BL) {
286 reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
287 if (reg < 0)
288 return reg;
289 seq_printf(seq, "battery\t\t: %s\n",
290 (reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
291 }
292 return 0;
293}
294
295static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
296{
297 struct i2c_client *client = to_i2c_client(dev);
298 int flags, retval;
299
300 flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
301 if (flags < 0)
302 return flags;
303
304 if (enabled)
305 flags |= M41T80_ALMON_AFE;
306 else
307 flags &= ~M41T80_ALMON_AFE;
308
309 retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
310 if (retval < 0) {
311 dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
312 return retval;
313 }
314 return 0;
315}
316
317static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
318{
319 struct i2c_client *client = to_i2c_client(dev);
320 u8 alarmvals[5];
321 int ret, err;
322
323 alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
324 alarmvals[1] = bin2bcd(alrm->time.tm_mday);
325 alarmvals[2] = bin2bcd(alrm->time.tm_hour);
326 alarmvals[3] = bin2bcd(alrm->time.tm_min);
327 alarmvals[4] = bin2bcd(alrm->time.tm_sec);
328
329 /* Clear AF and AFE flags */
330 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
331 if (ret < 0)
332 return ret;
333 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
334 ret & ~(M41T80_ALMON_AFE));
335 if (err < 0) {
336 dev_err(dev, "Unable to clear AFE bit\n");
337 return err;
338 }
339
340 /* Keep SQWE bit value */
341 alarmvals[0] |= (ret & M41T80_ALMON_SQWE);
342
343 ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
344 if (ret < 0)
345 return ret;
346
347 err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
348 ret & ~(M41T80_FLAGS_AF));
349 if (err < 0) {
350 dev_err(dev, "Unable to clear AF bit\n");
351 return err;
352 }
353
354 /* Write the alarm */
355 err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
356 5, alarmvals);
357 if (err)
358 return err;
359
360 /* Enable the alarm interrupt */
361 if (alrm->enabled) {
362 alarmvals[0] |= M41T80_ALMON_AFE;
363 err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
364 alarmvals[0]);
365 if (err)
366 return err;
367 }
368
369 return 0;
370}
371
372static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
373{
374 struct i2c_client *client = to_i2c_client(dev);
375 u8 alarmvals[5];
376 int flags, ret;
377
378 ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
379 5, alarmvals);
380 if (ret != 5)
381 return ret < 0 ? ret : -EIO;
382
383 flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
384 if (flags < 0)
385 return flags;
386
387 alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
388 alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
389 alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
390 alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
391 alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f) - 1;
392
393 alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
394 alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
395
396 return 0;
397}
398
399static const struct rtc_class_ops m41t80_rtc_ops = {
400 .read_time = m41t80_rtc_read_time,
401 .set_time = m41t80_rtc_set_time,
402 .proc = m41t80_rtc_proc,
403 .read_alarm = m41t80_read_alarm,
404 .set_alarm = m41t80_set_alarm,
405 .alarm_irq_enable = m41t80_alarm_irq_enable,
406};
407
408#ifdef CONFIG_PM_SLEEP
409static int m41t80_suspend(struct device *dev)
410{
411 struct i2c_client *client = to_i2c_client(dev);
412
413 if (client->irq >= 0 && device_may_wakeup(dev))
414 enable_irq_wake(client->irq);
415
416 return 0;
417}
418
419static int m41t80_resume(struct device *dev)
420{
421 struct i2c_client *client = to_i2c_client(dev);
422
423 if (client->irq >= 0 && device_may_wakeup(dev))
424 disable_irq_wake(client->irq);
425
426 return 0;
427}
428#endif
429
430static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
431
432#ifdef CONFIG_COMMON_CLK
433#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
434
435static unsigned long m41t80_decode_freq(int setting)
436{
437 return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ :
438 M41T80_SQW_MAX_FREQ >> setting;
439}
440
441static unsigned long m41t80_get_freq(struct m41t80_data *m41t80)
442{
443 struct i2c_client *client = m41t80->client;
444 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
445 M41T80_REG_WDAY : M41T80_REG_SQW;
446 int ret = i2c_smbus_read_byte_data(client, reg_sqw);
447
448 if (ret < 0)
449 return 0;
450 return m41t80_decode_freq(ret >> 4);
451}
452
453static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
454 unsigned long parent_rate)
455{
456 return sqw_to_m41t80_data(hw)->freq;
457}
458
459static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
460 unsigned long *prate)
461{
462 if (rate >= M41T80_SQW_MAX_FREQ)
463 return M41T80_SQW_MAX_FREQ;
464 if (rate >= M41T80_SQW_MAX_FREQ / 4)
465 return M41T80_SQW_MAX_FREQ / 4;
466 if (!rate)
467 return 0;
468 return 1 << ilog2(rate);
469}
470
471static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
472 unsigned long parent_rate)
473{
474 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
475 struct i2c_client *client = m41t80->client;
476 int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
477 M41T80_REG_WDAY : M41T80_REG_SQW;
478 int reg, ret, val = 0;
479
480 if (rate >= M41T80_SQW_MAX_FREQ)
481 val = 1;
482 else if (rate >= M41T80_SQW_MAX_FREQ / 4)
483 val = 2;
484 else if (rate)
485 val = 15 - ilog2(rate);
486
487 reg = i2c_smbus_read_byte_data(client, reg_sqw);
488 if (reg < 0)
489 return reg;
490
491 reg = (reg & 0x0f) | (val << 4);
492
493 ret = i2c_smbus_write_byte_data(client, reg_sqw, reg);
494 if (!ret)
495 m41t80->freq = m41t80_decode_freq(val);
496 return ret;
497}
498
499static int m41t80_sqw_control(struct clk_hw *hw, bool enable)
500{
501 struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
502 struct i2c_client *client = m41t80->client;
503 int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
504
505 if (ret < 0)
506 return ret;
507
508 if (enable)
509 ret |= M41T80_ALMON_SQWE;
510 else
511 ret &= ~M41T80_ALMON_SQWE;
512
513 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
514 if (!ret)
515 m41t80->sqwe = enable;
516 return ret;
517}
518
519static int m41t80_sqw_prepare(struct clk_hw *hw)
520{
521 return m41t80_sqw_control(hw, 1);
522}
523
524static void m41t80_sqw_unprepare(struct clk_hw *hw)
525{
526 m41t80_sqw_control(hw, 0);
527}
528
529static int m41t80_sqw_is_prepared(struct clk_hw *hw)
530{
531 return sqw_to_m41t80_data(hw)->sqwe;
532}
533
534static const struct clk_ops m41t80_sqw_ops = {
535 .prepare = m41t80_sqw_prepare,
536 .unprepare = m41t80_sqw_unprepare,
537 .is_prepared = m41t80_sqw_is_prepared,
538 .recalc_rate = m41t80_sqw_recalc_rate,
539 .round_rate = m41t80_sqw_round_rate,
540 .set_rate = m41t80_sqw_set_rate,
541};
542
543static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
544{
545 struct i2c_client *client = m41t80->client;
546 struct device_node *node = client->dev.of_node;
547 struct device_node *fixed_clock;
548 struct clk *clk;
549 struct clk_init_data init;
550 int ret;
551
552 fixed_clock = of_get_child_by_name(node, "clock");
553 if (fixed_clock) {
554 /*
555 * skip registering square wave clock when a fixed
556 * clock has been registered. The fixed clock is
557 * registered automatically when being referenced.
558 */
559 of_node_put(fixed_clock);
560 return NULL;
561 }
562
563 /* First disable the clock */
564 ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
565 if (ret < 0)
566 return ERR_PTR(ret);
567 ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
568 ret & ~(M41T80_ALMON_SQWE));
569 if (ret < 0)
570 return ERR_PTR(ret);
571
572 init.name = "m41t80-sqw";
573 init.ops = &m41t80_sqw_ops;
574 init.flags = 0;
575 init.parent_names = NULL;
576 init.num_parents = 0;
577 m41t80->sqw.init = &init;
578 m41t80->freq = m41t80_get_freq(m41t80);
579
580 /* optional override of the clockname */
581 of_property_read_string(node, "clock-output-names", &init.name);
582
583 /* register the clock */
584 clk = clk_register(&client->dev, &m41t80->sqw);
585 if (!IS_ERR(clk))
586 of_clk_add_provider(node, of_clk_src_simple_get, clk);
587
588 return clk;
589}
590#endif
591
592#ifdef CONFIG_RTC_DRV_M41T80_WDT
593/*
594 *****************************************************************************
595 *
596 * Watchdog Driver
597 *
598 *****************************************************************************
599 */
600static DEFINE_MUTEX(m41t80_rtc_mutex);
601static struct i2c_client *save_client;
602
603/* Default margin */
604#define WD_TIMO 60 /* 1..31 seconds */
605
606static int wdt_margin = WD_TIMO;
607module_param(wdt_margin, int, 0);
608MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
609
610static unsigned long wdt_is_open;
611static int boot_flag;
612
613/**
614 * wdt_ping - Reload counter one with the watchdog timeout.
615 * We don't bother reloading the cascade counter.
616 */
617static void wdt_ping(void)
618{
619 unsigned char i2c_data[2];
620 struct i2c_msg msgs1[1] = {
621 {
622 .addr = save_client->addr,
623 .flags = 0,
624 .len = 2,
625 .buf = i2c_data,
626 },
627 };
628 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
629
630 i2c_data[0] = 0x09; /* watchdog register */
631
632 if (wdt_margin > 31)
633 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
634 else
635 /*
636 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
637 */
638 i2c_data[1] = wdt_margin << 2 | 0x82;
639
640 /*
641 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
642 * that would be an invalid resolution.
643 */
644 if (clientdata->features & M41T80_FEATURE_WD)
645 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
646
647 i2c_transfer(save_client->adapter, msgs1, 1);
648}
649
650/**
651 * wdt_disable - disables watchdog.
652 */
653static void wdt_disable(void)
654{
655 unsigned char i2c_data[2], i2c_buf[0x10];
656 struct i2c_msg msgs0[2] = {
657 {
658 .addr = save_client->addr,
659 .flags = 0,
660 .len = 1,
661 .buf = i2c_data,
662 },
663 {
664 .addr = save_client->addr,
665 .flags = I2C_M_RD,
666 .len = 1,
667 .buf = i2c_buf,
668 },
669 };
670 struct i2c_msg msgs1[1] = {
671 {
672 .addr = save_client->addr,
673 .flags = 0,
674 .len = 2,
675 .buf = i2c_data,
676 },
677 };
678
679 i2c_data[0] = 0x09;
680 i2c_transfer(save_client->adapter, msgs0, 2);
681
682 i2c_data[0] = 0x09;
683 i2c_data[1] = 0x00;
684 i2c_transfer(save_client->adapter, msgs1, 1);
685}
686
687/**
688 * wdt_write - write to watchdog.
689 * @file: file handle to the watchdog
690 * @buf: buffer to write (unused as data does not matter here
691 * @count: count of bytes
692 * @ppos: pointer to the position to write. No seeks allowed
693 *
694 * A write to a watchdog device is defined as a keepalive signal. Any
695 * write of data will do, as we don't define content meaning.
696 */
697static ssize_t wdt_write(struct file *file, const char __user *buf,
698 size_t count, loff_t *ppos)
699{
700 if (count) {
701 wdt_ping();
702 return 1;
703 }
704 return 0;
705}
706
707static ssize_t wdt_read(struct file *file, char __user *buf,
708 size_t count, loff_t *ppos)
709{
710 return 0;
711}
712
713/**
714 * wdt_ioctl - ioctl handler to set watchdog.
715 * @file: file handle to the device
716 * @cmd: watchdog command
717 * @arg: argument pointer
718 *
719 * The watchdog API defines a common set of functions for all watchdogs
720 * according to their available features. We only actually usefully support
721 * querying capabilities and current status.
722 */
723static int wdt_ioctl(struct file *file, unsigned int cmd,
724 unsigned long arg)
725{
726 int new_margin, rv;
727 static struct watchdog_info ident = {
728 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
729 WDIOF_SETTIMEOUT,
730 .firmware_version = 1,
731 .identity = "M41T80 WTD"
732 };
733
734 switch (cmd) {
735 case WDIOC_GETSUPPORT:
736 return copy_to_user((struct watchdog_info __user *)arg, &ident,
737 sizeof(ident)) ? -EFAULT : 0;
738
739 case WDIOC_GETSTATUS:
740 case WDIOC_GETBOOTSTATUS:
741 return put_user(boot_flag, (int __user *)arg);
742 case WDIOC_KEEPALIVE:
743 wdt_ping();
744 return 0;
745 case WDIOC_SETTIMEOUT:
746 if (get_user(new_margin, (int __user *)arg))
747 return -EFAULT;
748 /* Arbitrary, can't find the card's limits */
749 if (new_margin < 1 || new_margin > 124)
750 return -EINVAL;
751 wdt_margin = new_margin;
752 wdt_ping();
753 fallthrough;
754 case WDIOC_GETTIMEOUT:
755 return put_user(wdt_margin, (int __user *)arg);
756
757 case WDIOC_SETOPTIONS:
758 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
759 return -EFAULT;
760
761 if (rv & WDIOS_DISABLECARD) {
762 pr_info("disable watchdog\n");
763 wdt_disable();
764 }
765
766 if (rv & WDIOS_ENABLECARD) {
767 pr_info("enable watchdog\n");
768 wdt_ping();
769 }
770
771 return -EINVAL;
772 }
773 return -ENOTTY;
774}
775
776static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
777 unsigned long arg)
778{
779 int ret;
780
781 mutex_lock(&m41t80_rtc_mutex);
782 ret = wdt_ioctl(file, cmd, arg);
783 mutex_unlock(&m41t80_rtc_mutex);
784
785 return ret;
786}
787
788/**
789 * wdt_open - open a watchdog.
790 * @inode: inode of device
791 * @file: file handle to device
792 *
793 */
794static int wdt_open(struct inode *inode, struct file *file)
795{
796 if (iminor(inode) == WATCHDOG_MINOR) {
797 mutex_lock(&m41t80_rtc_mutex);
798 if (test_and_set_bit(0, &wdt_is_open)) {
799 mutex_unlock(&m41t80_rtc_mutex);
800 return -EBUSY;
801 }
802 /*
803 * Activate
804 */
805 wdt_is_open = 1;
806 mutex_unlock(&m41t80_rtc_mutex);
807 return stream_open(inode, file);
808 }
809 return -ENODEV;
810}
811
812/**
813 * wdt_release - release a watchdog.
814 * @inode: inode to board
815 * @file: file handle to board
816 *
817 */
818static int wdt_release(struct inode *inode, struct file *file)
819{
820 if (iminor(inode) == WATCHDOG_MINOR)
821 clear_bit(0, &wdt_is_open);
822 return 0;
823}
824
825/**
826 * wdt_notify_sys - notify to watchdog.
827 * @this: our notifier block
828 * @code: the event being reported
829 * @unused: unused
830 *
831 * Our notifier is called on system shutdowns. We want to turn the card
832 * off at reboot otherwise the machine will reboot again during memory
833 * test or worse yet during the following fsck. This would suck, in fact
834 * trust me - if it happens it does suck.
835 */
836static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
837 void *unused)
838{
839 if (code == SYS_DOWN || code == SYS_HALT)
840 /* Disable Watchdog */
841 wdt_disable();
842 return NOTIFY_DONE;
843}
844
845static const struct file_operations wdt_fops = {
846 .owner = THIS_MODULE,
847 .read = wdt_read,
848 .unlocked_ioctl = wdt_unlocked_ioctl,
849 .compat_ioctl = compat_ptr_ioctl,
850 .write = wdt_write,
851 .open = wdt_open,
852 .release = wdt_release,
853};
854
855static struct miscdevice wdt_dev = {
856 .minor = WATCHDOG_MINOR,
857 .name = "watchdog",
858 .fops = &wdt_fops,
859};
860
861/*
862 * The WDT card needs to learn about soft shutdowns in order to
863 * turn the timebomb registers off.
864 */
865static struct notifier_block wdt_notifier = {
866 .notifier_call = wdt_notify_sys,
867};
868#endif /* CONFIG_RTC_DRV_M41T80_WDT */
869
870/*
871 *****************************************************************************
872 *
873 * Driver Interface
874 *
875 *****************************************************************************
876 */
877
878static int m41t80_probe(struct i2c_client *client)
879{
880 struct i2c_adapter *adapter = client->adapter;
881 int rc = 0;
882 struct rtc_time tm;
883 struct m41t80_data *m41t80_data = NULL;
884 bool wakeup_source = false;
885
886 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
887 I2C_FUNC_SMBUS_BYTE_DATA)) {
888 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
889 return -ENODEV;
890 }
891
892 m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
893 GFP_KERNEL);
894 if (!m41t80_data)
895 return -ENOMEM;
896
897 m41t80_data->client = client;
898 if (client->dev.of_node) {
899 m41t80_data->features = (unsigned long)
900 of_device_get_match_data(&client->dev);
901 } else {
902 const struct i2c_device_id *id = i2c_match_id(m41t80_id, client);
903 m41t80_data->features = id->driver_data;
904 }
905 i2c_set_clientdata(client, m41t80_data);
906
907 m41t80_data->rtc = devm_rtc_allocate_device(&client->dev);
908 if (IS_ERR(m41t80_data->rtc))
909 return PTR_ERR(m41t80_data->rtc);
910
911 wakeup_source = device_property_read_bool(&client->dev, "wakeup-source");
912 if (client->irq > 0) {
913 unsigned long irqflags = IRQF_TRIGGER_LOW;
914
915 if (dev_fwnode(&client->dev))
916 irqflags = 0;
917
918 rc = devm_request_threaded_irq(&client->dev, client->irq,
919 NULL, m41t80_handle_irq,
920 irqflags | IRQF_ONESHOT,
921 "m41t80", client);
922 if (rc) {
923 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
924 client->irq = 0;
925 wakeup_source = false;
926 }
927 }
928 if (client->irq > 0 || wakeup_source)
929 device_init_wakeup(&client->dev, true);
930 else
931 clear_bit(RTC_FEATURE_ALARM, m41t80_data->rtc->features);
932
933 m41t80_data->rtc->ops = &m41t80_rtc_ops;
934 m41t80_data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
935 m41t80_data->rtc->range_max = RTC_TIMESTAMP_END_2099;
936
937 if (client->irq <= 0)
938 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, m41t80_data->rtc->features);
939
940 /* Make sure HT (Halt Update) bit is cleared */
941 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
942
943 if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
944 if (m41t80_data->features & M41T80_FEATURE_HT) {
945 m41t80_rtc_read_time(&client->dev, &tm);
946 dev_info(&client->dev, "HT bit was set!\n");
947 dev_info(&client->dev, "Power Down at %ptR\n", &tm);
948 }
949 rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
950 rc & ~M41T80_ALHOUR_HT);
951 }
952
953 if (rc < 0) {
954 dev_err(&client->dev, "Can't clear HT bit\n");
955 return rc;
956 }
957
958 /* Make sure ST (stop) bit is cleared */
959 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
960
961 if (rc >= 0 && rc & M41T80_SEC_ST)
962 rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
963 rc & ~M41T80_SEC_ST);
964 if (rc < 0) {
965 dev_err(&client->dev, "Can't clear ST bit\n");
966 return rc;
967 }
968
969#ifdef CONFIG_RTC_DRV_M41T80_WDT
970 if (m41t80_data->features & M41T80_FEATURE_HT) {
971 save_client = client;
972 rc = misc_register(&wdt_dev);
973 if (rc)
974 return rc;
975 rc = register_reboot_notifier(&wdt_notifier);
976 if (rc) {
977 misc_deregister(&wdt_dev);
978 return rc;
979 }
980 }
981#endif
982#ifdef CONFIG_COMMON_CLK
983 if (m41t80_data->features & M41T80_FEATURE_SQ)
984 m41t80_sqw_register_clk(m41t80_data);
985#endif
986
987 rc = devm_rtc_register_device(m41t80_data->rtc);
988 if (rc)
989 return rc;
990
991 return 0;
992}
993
994static void m41t80_remove(struct i2c_client *client)
995{
996#ifdef CONFIG_RTC_DRV_M41T80_WDT
997 struct m41t80_data *clientdata = i2c_get_clientdata(client);
998
999 if (clientdata->features & M41T80_FEATURE_HT) {
1000 misc_deregister(&wdt_dev);
1001 unregister_reboot_notifier(&wdt_notifier);
1002 }
1003#endif
1004}
1005
1006static struct i2c_driver m41t80_driver = {
1007 .driver = {
1008 .name = "rtc-m41t80",
1009 .of_match_table = of_match_ptr(m41t80_of_match),
1010 .pm = &m41t80_pm,
1011 },
1012 .probe = m41t80_probe,
1013 .remove = m41t80_remove,
1014 .id_table = m41t80_id,
1015};
1016
1017module_i2c_driver(m41t80_driver);
1018
1019MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
1020MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
1021MODULE_LICENSE("GPL");
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
216/*
217 * XXX - m41t80 alarm functionality is reported broken.
218 * until it is fixed, don't register alarm functions.
219 */
220static struct rtc_class_ops m41t80_rtc_ops = {
221 .read_time = m41t80_rtc_read_time,
222 .set_time = m41t80_rtc_set_time,
223 .proc = m41t80_rtc_proc,
224};
225
226#if defined(CONFIG_RTC_INTF_SYSFS) || defined(CONFIG_RTC_INTF_SYSFS_MODULE)
227static ssize_t m41t80_sysfs_show_flags(struct device *dev,
228 struct device_attribute *attr, char *buf)
229{
230 struct i2c_client *client = to_i2c_client(dev);
231 int val;
232
233 val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
234 if (val < 0)
235 return -EIO;
236 return sprintf(buf, "%#x\n", val);
237}
238static DEVICE_ATTR(flags, S_IRUGO, m41t80_sysfs_show_flags, NULL);
239
240static ssize_t m41t80_sysfs_show_sqwfreq(struct device *dev,
241 struct device_attribute *attr, char *buf)
242{
243 struct i2c_client *client = to_i2c_client(dev);
244 struct m41t80_data *clientdata = i2c_get_clientdata(client);
245 int val, reg_sqw;
246
247 if (!(clientdata->features & M41T80_FEATURE_SQ))
248 return -EINVAL;
249
250 reg_sqw = M41T80_REG_SQW;
251 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
252 reg_sqw = M41T80_REG_WDAY;
253 val = i2c_smbus_read_byte_data(client, reg_sqw);
254 if (val < 0)
255 return -EIO;
256 val = (val >> 4) & 0xf;
257 switch (val) {
258 case 0:
259 break;
260 case 1:
261 val = 32768;
262 break;
263 default:
264 val = 32768 >> val;
265 }
266 return sprintf(buf, "%d\n", val);
267}
268static ssize_t m41t80_sysfs_set_sqwfreq(struct device *dev,
269 struct device_attribute *attr,
270 const char *buf, size_t count)
271{
272 struct i2c_client *client = to_i2c_client(dev);
273 struct m41t80_data *clientdata = i2c_get_clientdata(client);
274 int almon, sqw, reg_sqw;
275 int val = simple_strtoul(buf, NULL, 0);
276
277 if (!(clientdata->features & M41T80_FEATURE_SQ))
278 return -EINVAL;
279
280 if (val) {
281 if (!is_power_of_2(val))
282 return -EINVAL;
283 val = ilog2(val);
284 if (val == 15)
285 val = 1;
286 else if (val < 14)
287 val = 15 - val;
288 else
289 return -EINVAL;
290 }
291 /* disable SQW, set SQW frequency & re-enable */
292 almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
293 if (almon < 0)
294 return -EIO;
295 reg_sqw = M41T80_REG_SQW;
296 if (clientdata->features & M41T80_FEATURE_SQ_ALT)
297 reg_sqw = M41T80_REG_WDAY;
298 sqw = i2c_smbus_read_byte_data(client, reg_sqw);
299 if (sqw < 0)
300 return -EIO;
301 sqw = (sqw & 0x0f) | (val << 4);
302 if (i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
303 almon & ~M41T80_ALMON_SQWE) < 0 ||
304 i2c_smbus_write_byte_data(client, reg_sqw, sqw) < 0)
305 return -EIO;
306 if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
307 almon | M41T80_ALMON_SQWE) < 0)
308 return -EIO;
309 return count;
310}
311static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
312 m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);
313
314static struct attribute *attrs[] = {
315 &dev_attr_flags.attr,
316 &dev_attr_sqwfreq.attr,
317 NULL,
318};
319static struct attribute_group attr_group = {
320 .attrs = attrs,
321};
322
323static int m41t80_sysfs_register(struct device *dev)
324{
325 return sysfs_create_group(&dev->kobj, &attr_group);
326}
327#else
328static int m41t80_sysfs_register(struct device *dev)
329{
330 return 0;
331}
332#endif
333
334#ifdef CONFIG_RTC_DRV_M41T80_WDT
335/*
336 *****************************************************************************
337 *
338 * Watchdog Driver
339 *
340 *****************************************************************************
341 */
342static struct i2c_client *save_client;
343
344/* Default margin */
345#define WD_TIMO 60 /* 1..31 seconds */
346
347static int wdt_margin = WD_TIMO;
348module_param(wdt_margin, int, 0);
349MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");
350
351static unsigned long wdt_is_open;
352static int boot_flag;
353
354/**
355 * wdt_ping:
356 *
357 * Reload counter one with the watchdog timeout. We don't bother reloading
358 * the cascade counter.
359 */
360static void wdt_ping(void)
361{
362 unsigned char i2c_data[2];
363 struct i2c_msg msgs1[1] = {
364 {
365 .addr = save_client->addr,
366 .flags = 0,
367 .len = 2,
368 .buf = i2c_data,
369 },
370 };
371 struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
372
373 i2c_data[0] = 0x09; /* watchdog register */
374
375 if (wdt_margin > 31)
376 i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
377 else
378 /*
379 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
380 */
381 i2c_data[1] = wdt_margin<<2 | 0x82;
382
383 /*
384 * M41T65 has three bits for watchdog resolution. Don't set bit 7, as
385 * that would be an invalid resolution.
386 */
387 if (clientdata->features & M41T80_FEATURE_WD)
388 i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
389
390 i2c_transfer(save_client->adapter, msgs1, 1);
391}
392
393/**
394 * wdt_disable:
395 *
396 * disables watchdog.
397 */
398static void wdt_disable(void)
399{
400 unsigned char i2c_data[2], i2c_buf[0x10];
401 struct i2c_msg msgs0[2] = {
402 {
403 .addr = save_client->addr,
404 .flags = 0,
405 .len = 1,
406 .buf = i2c_data,
407 },
408 {
409 .addr = save_client->addr,
410 .flags = I2C_M_RD,
411 .len = 1,
412 .buf = i2c_buf,
413 },
414 };
415 struct i2c_msg msgs1[1] = {
416 {
417 .addr = save_client->addr,
418 .flags = 0,
419 .len = 2,
420 .buf = i2c_data,
421 },
422 };
423
424 i2c_data[0] = 0x09;
425 i2c_transfer(save_client->adapter, msgs0, 2);
426
427 i2c_data[0] = 0x09;
428 i2c_data[1] = 0x00;
429 i2c_transfer(save_client->adapter, msgs1, 1);
430}
431
432/**
433 * wdt_write:
434 * @file: file handle to the watchdog
435 * @buf: buffer to write (unused as data does not matter here
436 * @count: count of bytes
437 * @ppos: pointer to the position to write. No seeks allowed
438 *
439 * A write to a watchdog device is defined as a keepalive signal. Any
440 * write of data will do, as we we don't define content meaning.
441 */
442static ssize_t wdt_write(struct file *file, const char __user *buf,
443 size_t count, loff_t *ppos)
444{
445 if (count) {
446 wdt_ping();
447 return 1;
448 }
449 return 0;
450}
451
452static ssize_t wdt_read(struct file *file, char __user *buf,
453 size_t count, loff_t *ppos)
454{
455 return 0;
456}
457
458/**
459 * wdt_ioctl:
460 * @inode: inode of the device
461 * @file: file handle to the device
462 * @cmd: watchdog command
463 * @arg: argument pointer
464 *
465 * The watchdog API defines a common set of functions for all watchdogs
466 * according to their available features. We only actually usefully support
467 * querying capabilities and current status.
468 */
469static int wdt_ioctl(struct file *file, unsigned int cmd,
470 unsigned long arg)
471{
472 int new_margin, rv;
473 static struct watchdog_info ident = {
474 .options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
475 WDIOF_SETTIMEOUT,
476 .firmware_version = 1,
477 .identity = "M41T80 WTD"
478 };
479
480 switch (cmd) {
481 case WDIOC_GETSUPPORT:
482 return copy_to_user((struct watchdog_info __user *)arg, &ident,
483 sizeof(ident)) ? -EFAULT : 0;
484
485 case WDIOC_GETSTATUS:
486 case WDIOC_GETBOOTSTATUS:
487 return put_user(boot_flag, (int __user *)arg);
488 case WDIOC_KEEPALIVE:
489 wdt_ping();
490 return 0;
491 case WDIOC_SETTIMEOUT:
492 if (get_user(new_margin, (int __user *)arg))
493 return -EFAULT;
494 /* Arbitrary, can't find the card's limits */
495 if (new_margin < 1 || new_margin > 124)
496 return -EINVAL;
497 wdt_margin = new_margin;
498 wdt_ping();
499 /* Fall */
500 case WDIOC_GETTIMEOUT:
501 return put_user(wdt_margin, (int __user *)arg);
502
503 case WDIOC_SETOPTIONS:
504 if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
505 return -EFAULT;
506
507 if (rv & WDIOS_DISABLECARD) {
508 pr_info("rtc-m41t80: disable watchdog\n");
509 wdt_disable();
510 }
511
512 if (rv & WDIOS_ENABLECARD) {
513 pr_info("rtc-m41t80: enable watchdog\n");
514 wdt_ping();
515 }
516
517 return -EINVAL;
518 }
519 return -ENOTTY;
520}
521
522static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
523 unsigned long arg)
524{
525 int ret;
526
527 mutex_lock(&m41t80_rtc_mutex);
528 ret = wdt_ioctl(file, cmd, arg);
529 mutex_unlock(&m41t80_rtc_mutex);
530
531 return ret;
532}
533
534/**
535 * wdt_open:
536 * @inode: inode of device
537 * @file: file handle to device
538 *
539 */
540static int wdt_open(struct inode *inode, struct file *file)
541{
542 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
543 mutex_lock(&m41t80_rtc_mutex);
544 if (test_and_set_bit(0, &wdt_is_open)) {
545 mutex_unlock(&m41t80_rtc_mutex);
546 return -EBUSY;
547 }
548 /*
549 * Activate
550 */
551 wdt_is_open = 1;
552 mutex_unlock(&m41t80_rtc_mutex);
553 return nonseekable_open(inode, file);
554 }
555 return -ENODEV;
556}
557
558/**
559 * wdt_close:
560 * @inode: inode to board
561 * @file: file handle to board
562 *
563 */
564static int wdt_release(struct inode *inode, struct file *file)
565{
566 if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
567 clear_bit(0, &wdt_is_open);
568 return 0;
569}
570
571/**
572 * notify_sys:
573 * @this: our notifier block
574 * @code: the event being reported
575 * @unused: unused
576 *
577 * Our notifier is called on system shutdowns. We want to turn the card
578 * off at reboot otherwise the machine will reboot again during memory
579 * test or worse yet during the following fsck. This would suck, in fact
580 * trust me - if it happens it does suck.
581 */
582static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
583 void *unused)
584{
585 if (code == SYS_DOWN || code == SYS_HALT)
586 /* Disable Watchdog */
587 wdt_disable();
588 return NOTIFY_DONE;
589}
590
591static const struct file_operations wdt_fops = {
592 .owner = THIS_MODULE,
593 .read = wdt_read,
594 .unlocked_ioctl = wdt_unlocked_ioctl,
595 .write = wdt_write,
596 .open = wdt_open,
597 .release = wdt_release,
598 .llseek = no_llseek,
599};
600
601static struct miscdevice wdt_dev = {
602 .minor = WATCHDOG_MINOR,
603 .name = "watchdog",
604 .fops = &wdt_fops,
605};
606
607/*
608 * The WDT card needs to learn about soft shutdowns in order to
609 * turn the timebomb registers off.
610 */
611static struct notifier_block wdt_notifier = {
612 .notifier_call = wdt_notify_sys,
613};
614#endif /* CONFIG_RTC_DRV_M41T80_WDT */
615
616/*
617 *****************************************************************************
618 *
619 * Driver Interface
620 *
621 *****************************************************************************
622 */
623static int m41t80_probe(struct i2c_client *client,
624 const struct i2c_device_id *id)
625{
626 int rc = 0;
627 struct rtc_device *rtc = NULL;
628 struct rtc_time tm;
629 struct m41t80_data *clientdata = NULL;
630
631 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
632 | I2C_FUNC_SMBUS_BYTE_DATA)) {
633 rc = -ENODEV;
634 goto exit;
635 }
636
637 dev_info(&client->dev,
638 "chip found, driver version " DRV_VERSION "\n");
639
640 clientdata = devm_kzalloc(&client->dev, sizeof(*clientdata),
641 GFP_KERNEL);
642 if (!clientdata) {
643 rc = -ENOMEM;
644 goto exit;
645 }
646
647 clientdata->features = id->driver_data;
648 i2c_set_clientdata(client, clientdata);
649
650 rtc = devm_rtc_device_register(&client->dev, client->name,
651 &m41t80_rtc_ops, THIS_MODULE);
652 if (IS_ERR(rtc)) {
653 rc = PTR_ERR(rtc);
654 rtc = NULL;
655 goto exit;
656 }
657
658 clientdata->rtc = rtc;
659
660 /* Make sure HT (Halt Update) bit is cleared */
661 rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
662 if (rc < 0)
663 goto ht_err;
664
665 if (rc & M41T80_ALHOUR_HT) {
666 if (clientdata->features & M41T80_FEATURE_HT) {
667 m41t80_get_datetime(client, &tm);
668 dev_info(&client->dev, "HT bit was set!\n");
669 dev_info(&client->dev,
670 "Power Down at "
671 "%04i-%02i-%02i %02i:%02i:%02i\n",
672 tm.tm_year + 1900,
673 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
674 tm.tm_min, tm.tm_sec);
675 }
676 if (i2c_smbus_write_byte_data(client,
677 M41T80_REG_ALARM_HOUR,
678 rc & ~M41T80_ALHOUR_HT) < 0)
679 goto ht_err;
680 }
681
682 /* Make sure ST (stop) bit is cleared */
683 rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
684 if (rc < 0)
685 goto st_err;
686
687 if (rc & M41T80_SEC_ST) {
688 if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
689 rc & ~M41T80_SEC_ST) < 0)
690 goto st_err;
691 }
692
693 rc = m41t80_sysfs_register(&client->dev);
694 if (rc)
695 goto exit;
696
697#ifdef CONFIG_RTC_DRV_M41T80_WDT
698 if (clientdata->features & M41T80_FEATURE_HT) {
699 save_client = client;
700 rc = misc_register(&wdt_dev);
701 if (rc)
702 goto exit;
703 rc = register_reboot_notifier(&wdt_notifier);
704 if (rc) {
705 misc_deregister(&wdt_dev);
706 goto exit;
707 }
708 }
709#endif
710 return 0;
711
712st_err:
713 rc = -EIO;
714 dev_err(&client->dev, "Can't clear ST bit\n");
715 goto exit;
716ht_err:
717 rc = -EIO;
718 dev_err(&client->dev, "Can't clear HT bit\n");
719 goto exit;
720
721exit:
722 return rc;
723}
724
725static int m41t80_remove(struct i2c_client *client)
726{
727#ifdef CONFIG_RTC_DRV_M41T80_WDT
728 struct m41t80_data *clientdata = i2c_get_clientdata(client);
729
730 if (clientdata->features & M41T80_FEATURE_HT) {
731 misc_deregister(&wdt_dev);
732 unregister_reboot_notifier(&wdt_notifier);
733 }
734#endif
735
736 return 0;
737}
738
739static struct i2c_driver m41t80_driver = {
740 .driver = {
741 .name = "rtc-m41t80",
742 },
743 .probe = m41t80_probe,
744 .remove = m41t80_remove,
745 .id_table = m41t80_id,
746};
747
748module_i2c_driver(m41t80_driver);
749
750MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
751MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
752MODULE_LICENSE("GPL");
753MODULE_VERSION(DRV_VERSION);