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c03675f0 RZ |
1 | /* |
2 | * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C | |
3 | * | |
a2d6d2fa | 4 | * Copyright (C) 2009-2011 Freescale Semiconductor. |
f46418c5 | 5 | * Author: Jack Lan <jack.lan@freescale.com> |
c03675f0 RZ |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License as published by the | |
9 | * Free Software Foundation; either version 2 of the License, or (at your | |
10 | * option) any later version. | |
11 | */ | |
12 | /* | |
13 | * It would be more efficient to use i2c msgs/i2c_transfer directly but, as | |
14 | * recommened in .../Documentation/i2c/writing-clients section | |
15 | * "Sending and receiving", using SMBus level communication is preferred. | |
16 | */ | |
17 | ||
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/i2c.h> | |
22 | #include <linux/rtc.h> | |
23 | #include <linux/bcd.h> | |
24 | #include <linux/workqueue.h> | |
25 | #include <linux/slab.h> | |
26 | ||
27 | #define DS3232_REG_SECONDS 0x00 | |
28 | #define DS3232_REG_MINUTES 0x01 | |
29 | #define DS3232_REG_HOURS 0x02 | |
30 | #define DS3232_REG_AMPM 0x02 | |
31 | #define DS3232_REG_DAY 0x03 | |
32 | #define DS3232_REG_DATE 0x04 | |
33 | #define DS3232_REG_MONTH 0x05 | |
34 | #define DS3232_REG_CENTURY 0x05 | |
35 | #define DS3232_REG_YEAR 0x06 | |
36 | #define DS3232_REG_ALARM1 0x07 /* Alarm 1 BASE */ | |
37 | #define DS3232_REG_ALARM2 0x0B /* Alarm 2 BASE */ | |
38 | #define DS3232_REG_CR 0x0E /* Control register */ | |
39 | # define DS3232_REG_CR_nEOSC 0x80 | |
40 | # define DS3232_REG_CR_INTCN 0x04 | |
41 | # define DS3232_REG_CR_A2IE 0x02 | |
42 | # define DS3232_REG_CR_A1IE 0x01 | |
43 | ||
44 | #define DS3232_REG_SR 0x0F /* control/status register */ | |
45 | # define DS3232_REG_SR_OSF 0x80 | |
46 | # define DS3232_REG_SR_BSY 0x04 | |
47 | # define DS3232_REG_SR_A2F 0x02 | |
48 | # define DS3232_REG_SR_A1F 0x01 | |
49 | ||
50 | struct ds3232 { | |
51 | struct i2c_client *client; | |
52 | struct rtc_device *rtc; | |
53 | struct work_struct work; | |
54 | ||
55 | /* The mutex protects alarm operations, and prevents a race | |
56 | * between the enable_irq() in the workqueue and the free_irq() | |
57 | * in the remove function. | |
58 | */ | |
59 | struct mutex mutex; | |
c93a3ae2 | 60 | bool suspended; |
c03675f0 RZ |
61 | int exiting; |
62 | }; | |
63 | ||
64 | static struct i2c_driver ds3232_driver; | |
65 | ||
66 | static int ds3232_check_rtc_status(struct i2c_client *client) | |
67 | { | |
68 | int ret = 0; | |
69 | int control, stat; | |
70 | ||
71 | stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); | |
72 | if (stat < 0) | |
73 | return stat; | |
74 | ||
75 | if (stat & DS3232_REG_SR_OSF) | |
76 | dev_warn(&client->dev, | |
77 | "oscillator discontinuity flagged, " | |
78 | "time unreliable\n"); | |
79 | ||
80 | stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); | |
81 | ||
82 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); | |
83 | if (ret < 0) | |
84 | return ret; | |
85 | ||
86 | /* If the alarm is pending, clear it before requesting | |
87 | * the interrupt, so an interrupt event isn't reported | |
88 | * before everything is initialized. | |
89 | */ | |
90 | ||
91 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); | |
92 | if (control < 0) | |
93 | return control; | |
94 | ||
95 | control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); | |
96 | control |= DS3232_REG_CR_INTCN; | |
97 | ||
98 | return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); | |
99 | } | |
100 | ||
101 | static int ds3232_read_time(struct device *dev, struct rtc_time *time) | |
102 | { | |
103 | struct i2c_client *client = to_i2c_client(dev); | |
104 | int ret; | |
105 | u8 buf[7]; | |
106 | unsigned int year, month, day, hour, minute, second; | |
107 | unsigned int week, twelve_hr, am_pm; | |
108 | unsigned int century, add_century = 0; | |
109 | ||
110 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf); | |
111 | ||
112 | if (ret < 0) | |
113 | return ret; | |
114 | if (ret < 7) | |
115 | return -EIO; | |
116 | ||
117 | second = buf[0]; | |
118 | minute = buf[1]; | |
119 | hour = buf[2]; | |
120 | week = buf[3]; | |
121 | day = buf[4]; | |
122 | month = buf[5]; | |
123 | year = buf[6]; | |
124 | ||
125 | /* Extract additional information for AM/PM and century */ | |
126 | ||
127 | twelve_hr = hour & 0x40; | |
128 | am_pm = hour & 0x20; | |
129 | century = month & 0x80; | |
130 | ||
131 | /* Write to rtc_time structure */ | |
132 | ||
133 | time->tm_sec = bcd2bin(second); | |
134 | time->tm_min = bcd2bin(minute); | |
135 | if (twelve_hr) { | |
136 | /* Convert to 24 hr */ | |
137 | if (am_pm) | |
138 | time->tm_hour = bcd2bin(hour & 0x1F) + 12; | |
139 | else | |
140 | time->tm_hour = bcd2bin(hour & 0x1F); | |
141 | } else { | |
142 | time->tm_hour = bcd2bin(hour); | |
143 | } | |
144 | ||
a2d6d2fa LX |
145 | /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ |
146 | time->tm_wday = bcd2bin(week) - 1; | |
c03675f0 | 147 | time->tm_mday = bcd2bin(day); |
a2d6d2fa LX |
148 | /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ |
149 | time->tm_mon = bcd2bin(month & 0x7F) - 1; | |
c03675f0 RZ |
150 | if (century) |
151 | add_century = 100; | |
152 | ||
153 | time->tm_year = bcd2bin(year) + add_century; | |
154 | ||
155 | return rtc_valid_tm(time); | |
156 | } | |
157 | ||
158 | static int ds3232_set_time(struct device *dev, struct rtc_time *time) | |
159 | { | |
160 | struct i2c_client *client = to_i2c_client(dev); | |
161 | u8 buf[7]; | |
162 | ||
163 | /* Extract time from rtc_time and load into ds3232*/ | |
164 | ||
165 | buf[0] = bin2bcd(time->tm_sec); | |
166 | buf[1] = bin2bcd(time->tm_min); | |
167 | buf[2] = bin2bcd(time->tm_hour); | |
a2d6d2fa LX |
168 | /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */ |
169 | buf[3] = bin2bcd(time->tm_wday + 1); | |
c03675f0 | 170 | buf[4] = bin2bcd(time->tm_mday); /* Date */ |
a2d6d2fa LX |
171 | /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */ |
172 | buf[5] = bin2bcd(time->tm_mon + 1); | |
c03675f0 RZ |
173 | if (time->tm_year >= 100) { |
174 | buf[5] |= 0x80; | |
175 | buf[6] = bin2bcd(time->tm_year - 100); | |
176 | } else { | |
177 | buf[6] = bin2bcd(time->tm_year); | |
178 | } | |
179 | ||
180 | return i2c_smbus_write_i2c_block_data(client, | |
181 | DS3232_REG_SECONDS, 7, buf); | |
182 | } | |
183 | ||
f46418c5 LCB |
184 | /* |
185 | * DS3232 has two alarm, we only use alarm1 | |
186 | * According to linux specification, only support one-shot alarm | |
187 | * no periodic alarm mode | |
188 | */ | |
189 | static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
190 | { | |
191 | struct i2c_client *client = to_i2c_client(dev); | |
192 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
193 | int control, stat; | |
194 | int ret; | |
195 | u8 buf[4]; | |
196 | ||
197 | mutex_lock(&ds3232->mutex); | |
198 | ||
199 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); | |
200 | if (ret < 0) | |
201 | goto out; | |
202 | stat = ret; | |
203 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); | |
204 | if (ret < 0) | |
205 | goto out; | |
206 | control = ret; | |
207 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); | |
208 | if (ret < 0) | |
209 | goto out; | |
210 | ||
211 | alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F); | |
212 | alarm->time.tm_min = bcd2bin(buf[1] & 0x7F); | |
213 | alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F); | |
214 | alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F); | |
215 | ||
216 | alarm->time.tm_mon = -1; | |
217 | alarm->time.tm_year = -1; | |
218 | alarm->time.tm_wday = -1; | |
219 | alarm->time.tm_yday = -1; | |
220 | alarm->time.tm_isdst = -1; | |
221 | ||
222 | alarm->enabled = !!(control & DS3232_REG_CR_A1IE); | |
223 | alarm->pending = !!(stat & DS3232_REG_SR_A1F); | |
224 | ||
225 | ret = 0; | |
226 | out: | |
227 | mutex_unlock(&ds3232->mutex); | |
228 | return ret; | |
229 | } | |
230 | ||
231 | /* | |
232 | * linux rtc-module does not support wday alarm | |
233 | * and only 24h time mode supported indeed | |
234 | */ | |
235 | static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
236 | { | |
237 | struct i2c_client *client = to_i2c_client(dev); | |
238 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
239 | int control, stat; | |
240 | int ret; | |
241 | u8 buf[4]; | |
242 | ||
243 | if (client->irq <= 0) | |
244 | return -EINVAL; | |
245 | ||
246 | mutex_lock(&ds3232->mutex); | |
247 | ||
248 | buf[0] = bin2bcd(alarm->time.tm_sec); | |
249 | buf[1] = bin2bcd(alarm->time.tm_min); | |
250 | buf[2] = bin2bcd(alarm->time.tm_hour); | |
251 | buf[3] = bin2bcd(alarm->time.tm_mday); | |
252 | ||
253 | /* clear alarm interrupt enable bit */ | |
254 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR); | |
255 | if (ret < 0) | |
256 | goto out; | |
257 | control = ret; | |
258 | control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE); | |
259 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); | |
260 | if (ret < 0) | |
261 | goto out; | |
262 | ||
263 | /* clear any pending alarm flag */ | |
264 | ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR); | |
265 | if (ret < 0) | |
266 | goto out; | |
267 | stat = ret; | |
268 | stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F); | |
269 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); | |
270 | if (ret < 0) | |
271 | goto out; | |
272 | ||
273 | ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); | |
274 | ||
275 | if (alarm->enabled) { | |
276 | control |= DS3232_REG_CR_A1IE; | |
277 | ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); | |
278 | } | |
279 | out: | |
280 | mutex_unlock(&ds3232->mutex); | |
281 | return ret; | |
282 | } | |
283 | ||
284 | static void ds3232_update_alarm(struct i2c_client *client) | |
285 | { | |
286 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
287 | int control; | |
288 | int ret; | |
289 | u8 buf[4]; | |
290 | ||
291 | mutex_lock(&ds3232->mutex); | |
292 | ||
293 | ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); | |
294 | if (ret < 0) | |
295 | goto unlock; | |
296 | ||
297 | buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? | |
298 | 0x80 : buf[0]; | |
299 | buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? | |
300 | 0x80 : buf[1]; | |
301 | buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? | |
302 | 0x80 : buf[2]; | |
303 | buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ? | |
304 | 0x80 : buf[3]; | |
305 | ||
306 | ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf); | |
307 | if (ret < 0) | |
308 | goto unlock; | |
309 | ||
310 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); | |
311 | if (control < 0) | |
312 | goto unlock; | |
313 | ||
314 | if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF)) | |
315 | /* enable alarm1 interrupt */ | |
316 | control |= DS3232_REG_CR_A1IE; | |
317 | else | |
318 | /* disable alarm1 interrupt */ | |
319 | control &= ~(DS3232_REG_CR_A1IE); | |
320 | i2c_smbus_write_byte_data(client, DS3232_REG_CR, control); | |
321 | ||
322 | unlock: | |
323 | mutex_unlock(&ds3232->mutex); | |
324 | } | |
325 | ||
326 | static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled) | |
327 | { | |
328 | struct i2c_client *client = to_i2c_client(dev); | |
329 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
330 | ||
331 | if (client->irq <= 0) | |
332 | return -EINVAL; | |
333 | ||
334 | if (enabled) | |
335 | ds3232->rtc->irq_data |= RTC_AF; | |
336 | else | |
337 | ds3232->rtc->irq_data &= ~RTC_AF; | |
338 | ||
339 | ds3232_update_alarm(client); | |
340 | return 0; | |
341 | } | |
342 | ||
c03675f0 RZ |
343 | static irqreturn_t ds3232_irq(int irq, void *dev_id) |
344 | { | |
345 | struct i2c_client *client = dev_id; | |
346 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
347 | ||
348 | disable_irq_nosync(irq); | |
c93a3ae2 WD |
349 | |
350 | /* | |
351 | * If rtc as a wakeup source, can't schedule the work | |
352 | * at system resume flow, because at this time the i2c bus | |
353 | * has not been resumed. | |
354 | */ | |
355 | if (!ds3232->suspended) | |
356 | schedule_work(&ds3232->work); | |
357 | ||
c03675f0 RZ |
358 | return IRQ_HANDLED; |
359 | } | |
360 | ||
361 | static void ds3232_work(struct work_struct *work) | |
362 | { | |
363 | struct ds3232 *ds3232 = container_of(work, struct ds3232, work); | |
364 | struct i2c_client *client = ds3232->client; | |
365 | int stat, control; | |
366 | ||
367 | mutex_lock(&ds3232->mutex); | |
368 | ||
369 | stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR); | |
370 | if (stat < 0) | |
371 | goto unlock; | |
372 | ||
373 | if (stat & DS3232_REG_SR_A1F) { | |
374 | control = i2c_smbus_read_byte_data(client, DS3232_REG_CR); | |
c93a3ae2 WD |
375 | if (control < 0) { |
376 | pr_warn("Read DS3232 Control Register error." | |
377 | "Disable IRQ%d.\n", client->irq); | |
378 | } else { | |
379 | /* disable alarm1 interrupt */ | |
380 | control &= ~(DS3232_REG_CR_A1IE); | |
381 | i2c_smbus_write_byte_data(client, DS3232_REG_CR, | |
382 | control); | |
383 | ||
384 | /* clear the alarm pend flag */ | |
385 | stat &= ~DS3232_REG_SR_A1F; | |
386 | i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat); | |
387 | ||
388 | rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF); | |
389 | ||
390 | if (!ds3232->exiting) | |
391 | enable_irq(client->irq); | |
392 | } | |
c03675f0 RZ |
393 | } |
394 | ||
c03675f0 RZ |
395 | unlock: |
396 | mutex_unlock(&ds3232->mutex); | |
397 | } | |
398 | ||
399 | static const struct rtc_class_ops ds3232_rtc_ops = { | |
400 | .read_time = ds3232_read_time, | |
401 | .set_time = ds3232_set_time, | |
f46418c5 LCB |
402 | .read_alarm = ds3232_read_alarm, |
403 | .set_alarm = ds3232_set_alarm, | |
404 | .alarm_irq_enable = ds3232_alarm_irq_enable, | |
c03675f0 RZ |
405 | }; |
406 | ||
5a167f45 GKH |
407 | static int ds3232_probe(struct i2c_client *client, |
408 | const struct i2c_device_id *id) | |
c03675f0 RZ |
409 | { |
410 | struct ds3232 *ds3232; | |
411 | int ret; | |
412 | ||
66714612 | 413 | ds3232 = devm_kzalloc(&client->dev, sizeof(struct ds3232), GFP_KERNEL); |
c03675f0 RZ |
414 | if (!ds3232) |
415 | return -ENOMEM; | |
416 | ||
417 | ds3232->client = client; | |
418 | i2c_set_clientdata(client, ds3232); | |
419 | ||
420 | INIT_WORK(&ds3232->work, ds3232_work); | |
421 | mutex_init(&ds3232->mutex); | |
422 | ||
423 | ret = ds3232_check_rtc_status(client); | |
424 | if (ret) | |
66714612 | 425 | return ret; |
c03675f0 | 426 | |
c93a3ae2 | 427 | if (client->irq > 0) { |
a8a15eb1 BB |
428 | ret = devm_request_irq(&client->dev, client->irq, ds3232_irq, |
429 | IRQF_SHARED, "ds3232", client); | |
c03675f0 RZ |
430 | if (ret) { |
431 | dev_err(&client->dev, "unable to request IRQ\n"); | |
c03675f0 | 432 | } |
c93a3ae2 | 433 | device_init_wakeup(&client->dev, 1); |
c03675f0 | 434 | } |
c93a3ae2 WD |
435 | ds3232->rtc = devm_rtc_device_register(&client->dev, client->name, |
436 | &ds3232_rtc_ops, THIS_MODULE); | |
437 | return PTR_ERR_OR_ZERO(ds3232->rtc); | |
c03675f0 RZ |
438 | } |
439 | ||
5a167f45 | 440 | static int ds3232_remove(struct i2c_client *client) |
c03675f0 RZ |
441 | { |
442 | struct ds3232 *ds3232 = i2c_get_clientdata(client); | |
443 | ||
444 | if (client->irq >= 0) { | |
445 | mutex_lock(&ds3232->mutex); | |
446 | ds3232->exiting = 1; | |
447 | mutex_unlock(&ds3232->mutex); | |
448 | ||
66714612 | 449 | devm_free_irq(&client->dev, client->irq, client); |
9db8995b | 450 | cancel_work_sync(&ds3232->work); |
c03675f0 RZ |
451 | } |
452 | ||
c03675f0 RZ |
453 | return 0; |
454 | } | |
455 | ||
c93a3ae2 WD |
456 | #ifdef CONFIG_PM_SLEEP |
457 | static int ds3232_suspend(struct device *dev) | |
458 | { | |
459 | struct ds3232 *ds3232 = dev_get_drvdata(dev); | |
460 | struct i2c_client *client = to_i2c_client(dev); | |
461 | ||
462 | if (device_can_wakeup(dev)) { | |
463 | ds3232->suspended = true; | |
464 | irq_set_irq_wake(client->irq, 1); | |
465 | } | |
466 | ||
467 | return 0; | |
468 | } | |
469 | ||
470 | static int ds3232_resume(struct device *dev) | |
471 | { | |
472 | struct ds3232 *ds3232 = dev_get_drvdata(dev); | |
473 | struct i2c_client *client = to_i2c_client(dev); | |
474 | ||
475 | if (ds3232->suspended) { | |
476 | ds3232->suspended = false; | |
477 | ||
478 | /* Clear the hardware alarm pend flag */ | |
479 | schedule_work(&ds3232->work); | |
480 | ||
481 | irq_set_irq_wake(client->irq, 0); | |
482 | } | |
483 | ||
484 | return 0; | |
485 | } | |
486 | #endif | |
487 | ||
488 | static const struct dev_pm_ops ds3232_pm_ops = { | |
489 | SET_SYSTEM_SLEEP_PM_OPS(ds3232_suspend, ds3232_resume) | |
490 | }; | |
491 | ||
c03675f0 RZ |
492 | static const struct i2c_device_id ds3232_id[] = { |
493 | { "ds3232", 0 }, | |
494 | { } | |
495 | }; | |
496 | MODULE_DEVICE_TABLE(i2c, ds3232_id); | |
497 | ||
498 | static struct i2c_driver ds3232_driver = { | |
499 | .driver = { | |
500 | .name = "rtc-ds3232", | |
501 | .owner = THIS_MODULE, | |
c93a3ae2 | 502 | .pm = &ds3232_pm_ops, |
c03675f0 RZ |
503 | }, |
504 | .probe = ds3232_probe, | |
5a167f45 | 505 | .remove = ds3232_remove, |
c03675f0 RZ |
506 | .id_table = ds3232_id, |
507 | }; | |
508 | ||
0abc9201 | 509 | module_i2c_driver(ds3232_driver); |
c03675f0 RZ |
510 | |
511 | MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>"); | |
512 | MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver"); | |
513 | MODULE_LICENSE("GPL"); |