Add linux-next specific files for 20110831
[linux-2.6/next.git] / drivers / rtc / rtc-ds3232.c
blob27b7bf672ac624249b2a64abda0464af5d74f2cc
1 /*
2 * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
4 * Copyright (C) 2009-2011 Freescale Semiconductor.
5 * Author: Jack Lan <jack.lan@freescale.com>
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.
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.
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>
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
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
50 struct ds3232 {
51 struct i2c_client *client;
52 struct rtc_device *rtc;
53 struct work_struct work;
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.
59 struct mutex mutex;
60 int exiting;
63 static struct i2c_driver ds3232_driver;
65 static int ds3232_check_rtc_status(struct i2c_client *client)
67 int ret = 0;
68 int control, stat;
70 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
71 if (stat < 0)
72 return stat;
74 if (stat & DS3232_REG_SR_OSF)
75 dev_warn(&client->dev,
76 "oscillator discontinuity flagged, "
77 "time unreliable\n");
79 stat &= ~(DS3232_REG_SR_OSF | DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
81 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
82 if (ret < 0)
83 return ret;
85 /* If the alarm is pending, clear it before requesting
86 * the interrupt, so an interrupt event isn't reported
87 * before everything is initialized.
90 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
91 if (control < 0)
92 return control;
94 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
95 control |= DS3232_REG_CR_INTCN;
97 return i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
100 static int ds3232_read_time(struct device *dev, struct rtc_time *time)
102 struct i2c_client *client = to_i2c_client(dev);
103 int ret;
104 u8 buf[7];
105 unsigned int year, month, day, hour, minute, second;
106 unsigned int week, twelve_hr, am_pm;
107 unsigned int century, add_century = 0;
109 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_SECONDS, 7, buf);
111 if (ret < 0)
112 return ret;
113 if (ret < 7)
114 return -EIO;
116 second = buf[0];
117 minute = buf[1];
118 hour = buf[2];
119 week = buf[3];
120 day = buf[4];
121 month = buf[5];
122 year = buf[6];
124 /* Extract additional information for AM/PM and century */
126 twelve_hr = hour & 0x40;
127 am_pm = hour & 0x20;
128 century = month & 0x80;
130 /* Write to rtc_time structure */
132 time->tm_sec = bcd2bin(second);
133 time->tm_min = bcd2bin(minute);
134 if (twelve_hr) {
135 /* Convert to 24 hr */
136 if (am_pm)
137 time->tm_hour = bcd2bin(hour & 0x1F) + 12;
138 else
139 time->tm_hour = bcd2bin(hour & 0x1F);
140 } else {
141 time->tm_hour = bcd2bin(hour);
144 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
145 time->tm_wday = bcd2bin(week) - 1;
146 time->tm_mday = bcd2bin(day);
147 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
148 time->tm_mon = bcd2bin(month & 0x7F) - 1;
149 if (century)
150 add_century = 100;
152 time->tm_year = bcd2bin(year) + add_century;
154 return rtc_valid_tm(time);
157 static int ds3232_set_time(struct device *dev, struct rtc_time *time)
159 struct i2c_client *client = to_i2c_client(dev);
160 u8 buf[7];
162 /* Extract time from rtc_time and load into ds3232*/
164 buf[0] = bin2bcd(time->tm_sec);
165 buf[1] = bin2bcd(time->tm_min);
166 buf[2] = bin2bcd(time->tm_hour);
167 /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
168 buf[3] = bin2bcd(time->tm_wday + 1);
169 buf[4] = bin2bcd(time->tm_mday); /* Date */
170 /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
171 buf[5] = bin2bcd(time->tm_mon + 1);
172 if (time->tm_year >= 100) {
173 buf[5] |= 0x80;
174 buf[6] = bin2bcd(time->tm_year - 100);
175 } else {
176 buf[6] = bin2bcd(time->tm_year);
179 return i2c_smbus_write_i2c_block_data(client,
180 DS3232_REG_SECONDS, 7, buf);
184 * DS3232 has two alarm, we only use alarm1
185 * According to linux specification, only support one-shot alarm
186 * no periodic alarm mode
188 static int ds3232_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
190 struct i2c_client *client = to_i2c_client(dev);
191 struct ds3232 *ds3232 = i2c_get_clientdata(client);
192 int control, stat;
193 int ret;
194 u8 buf[4];
196 mutex_lock(&ds3232->mutex);
198 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
199 if (ret < 0)
200 goto out;
201 stat = ret;
202 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
203 if (ret < 0)
204 goto out;
205 control = ret;
206 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
207 if (ret < 0)
208 goto out;
210 alarm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
211 alarm->time.tm_min = bcd2bin(buf[1] & 0x7F);
212 alarm->time.tm_hour = bcd2bin(buf[2] & 0x7F);
213 alarm->time.tm_mday = bcd2bin(buf[3] & 0x7F);
215 alarm->time.tm_mon = -1;
216 alarm->time.tm_year = -1;
217 alarm->time.tm_wday = -1;
218 alarm->time.tm_yday = -1;
219 alarm->time.tm_isdst = -1;
221 alarm->enabled = !!(control & DS3232_REG_CR_A1IE);
222 alarm->pending = !!(stat & DS3232_REG_SR_A1F);
224 ret = 0;
225 out:
226 mutex_unlock(&ds3232->mutex);
227 return ret;
231 * linux rtc-module does not support wday alarm
232 * and only 24h time mode supported indeed
234 static int ds3232_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
236 struct i2c_client *client = to_i2c_client(dev);
237 struct ds3232 *ds3232 = i2c_get_clientdata(client);
238 int control, stat;
239 int ret;
240 u8 buf[4];
242 if (client->irq <= 0)
243 return -EINVAL;
245 mutex_lock(&ds3232->mutex);
247 buf[0] = bin2bcd(alarm->time.tm_sec);
248 buf[1] = bin2bcd(alarm->time.tm_min);
249 buf[2] = bin2bcd(alarm->time.tm_hour);
250 buf[3] = bin2bcd(alarm->time.tm_mday);
252 /* clear alarm interrupt enable bit */
253 ret = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
254 if (ret < 0)
255 goto out;
256 control = ret;
257 control &= ~(DS3232_REG_CR_A1IE | DS3232_REG_CR_A2IE);
258 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
259 if (ret < 0)
260 goto out;
262 /* clear any pending alarm flag */
263 ret = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
264 if (ret < 0)
265 goto out;
266 stat = ret;
267 stat &= ~(DS3232_REG_SR_A1F | DS3232_REG_SR_A2F);
268 ret = i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
269 if (ret < 0)
270 goto out;
272 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
274 if (alarm->enabled) {
275 control |= DS3232_REG_CR_A1IE;
276 ret = i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
278 out:
279 mutex_unlock(&ds3232->mutex);
280 return ret;
283 static void ds3232_update_alarm(struct i2c_client *client)
285 struct ds3232 *ds3232 = i2c_get_clientdata(client);
286 int control;
287 int ret;
288 u8 buf[4];
290 mutex_lock(&ds3232->mutex);
292 ret = i2c_smbus_read_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
293 if (ret < 0)
294 goto unlock;
296 buf[0] = bcd2bin(buf[0]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
297 0x80 : buf[0];
298 buf[1] = bcd2bin(buf[1]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
299 0x80 : buf[1];
300 buf[2] = bcd2bin(buf[2]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
301 0x80 : buf[2];
302 buf[3] = bcd2bin(buf[3]) < 0 || (ds3232->rtc->irq_data & RTC_UF) ?
303 0x80 : buf[3];
305 ret = i2c_smbus_write_i2c_block_data(client, DS3232_REG_ALARM1, 4, buf);
306 if (ret < 0)
307 goto unlock;
309 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
310 if (control < 0)
311 goto unlock;
313 if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF))
314 /* enable alarm1 interrupt */
315 control |= DS3232_REG_CR_A1IE;
316 else
317 /* disable alarm1 interrupt */
318 control &= ~(DS3232_REG_CR_A1IE);
319 i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
321 unlock:
322 mutex_unlock(&ds3232->mutex);
325 static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
327 struct i2c_client *client = to_i2c_client(dev);
328 struct ds3232 *ds3232 = i2c_get_clientdata(client);
330 if (client->irq <= 0)
331 return -EINVAL;
333 if (enabled)
334 ds3232->rtc->irq_data |= RTC_AF;
335 else
336 ds3232->rtc->irq_data &= ~RTC_AF;
338 ds3232_update_alarm(client);
339 return 0;
342 static irqreturn_t ds3232_irq(int irq, void *dev_id)
344 struct i2c_client *client = dev_id;
345 struct ds3232 *ds3232 = i2c_get_clientdata(client);
347 disable_irq_nosync(irq);
348 schedule_work(&ds3232->work);
349 return IRQ_HANDLED;
352 static void ds3232_work(struct work_struct *work)
354 struct ds3232 *ds3232 = container_of(work, struct ds3232, work);
355 struct i2c_client *client = ds3232->client;
356 int stat, control;
358 mutex_lock(&ds3232->mutex);
360 stat = i2c_smbus_read_byte_data(client, DS3232_REG_SR);
361 if (stat < 0)
362 goto unlock;
364 if (stat & DS3232_REG_SR_A1F) {
365 control = i2c_smbus_read_byte_data(client, DS3232_REG_CR);
366 if (control < 0)
367 goto out;
368 /* disable alarm1 interrupt */
369 control &= ~(DS3232_REG_CR_A1IE);
370 i2c_smbus_write_byte_data(client, DS3232_REG_CR, control);
372 /* clear the alarm pend flag */
373 stat &= ~DS3232_REG_SR_A1F;
374 i2c_smbus_write_byte_data(client, DS3232_REG_SR, stat);
376 rtc_update_irq(ds3232->rtc, 1, RTC_AF | RTC_IRQF);
379 out:
380 if (!ds3232->exiting)
381 enable_irq(client->irq);
382 unlock:
383 mutex_unlock(&ds3232->mutex);
386 static const struct rtc_class_ops ds3232_rtc_ops = {
387 .read_time = ds3232_read_time,
388 .set_time = ds3232_set_time,
389 .read_alarm = ds3232_read_alarm,
390 .set_alarm = ds3232_set_alarm,
391 .alarm_irq_enable = ds3232_alarm_irq_enable,
394 static int __devinit ds3232_probe(struct i2c_client *client,
395 const struct i2c_device_id *id)
397 struct ds3232 *ds3232;
398 int ret;
400 ds3232 = kzalloc(sizeof(struct ds3232), GFP_KERNEL);
401 if (!ds3232)
402 return -ENOMEM;
404 ds3232->client = client;
405 i2c_set_clientdata(client, ds3232);
407 INIT_WORK(&ds3232->work, ds3232_work);
408 mutex_init(&ds3232->mutex);
410 ret = ds3232_check_rtc_status(client);
411 if (ret)
412 goto out_free;
414 ds3232->rtc = rtc_device_register(client->name, &client->dev,
415 &ds3232_rtc_ops, THIS_MODULE);
416 if (IS_ERR(ds3232->rtc)) {
417 ret = PTR_ERR(ds3232->rtc);
418 dev_err(&client->dev, "unable to register the class device\n");
419 goto out_irq;
422 if (client->irq >= 0) {
423 ret = request_irq(client->irq, ds3232_irq, 0,
424 "ds3232", client);
425 if (ret) {
426 dev_err(&client->dev, "unable to request IRQ\n");
427 goto out_free;
431 return 0;
433 out_irq:
434 if (client->irq >= 0)
435 free_irq(client->irq, client);
437 out_free:
438 kfree(ds3232);
439 return ret;
442 static int __devexit ds3232_remove(struct i2c_client *client)
444 struct ds3232 *ds3232 = i2c_get_clientdata(client);
446 if (client->irq >= 0) {
447 mutex_lock(&ds3232->mutex);
448 ds3232->exiting = 1;
449 mutex_unlock(&ds3232->mutex);
451 free_irq(client->irq, client);
452 cancel_work_sync(&ds3232->work);
455 rtc_device_unregister(ds3232->rtc);
456 kfree(ds3232);
457 return 0;
460 static const struct i2c_device_id ds3232_id[] = {
461 { "ds3232", 0 },
464 MODULE_DEVICE_TABLE(i2c, ds3232_id);
466 static struct i2c_driver ds3232_driver = {
467 .driver = {
468 .name = "rtc-ds3232",
469 .owner = THIS_MODULE,
471 .probe = ds3232_probe,
472 .remove = __devexit_p(ds3232_remove),
473 .id_table = ds3232_id,
476 static int __init ds3232_init(void)
478 return i2c_add_driver(&ds3232_driver);
481 static void __exit ds3232_exit(void)
483 i2c_del_driver(&ds3232_driver);
486 module_init(ds3232_init);
487 module_exit(ds3232_exit);
489 MODULE_AUTHOR("Srikanth Srinivasan <srikanth.srinivasan@freescale.com>");
490 MODULE_DESCRIPTION("Maxim/Dallas DS3232 RTC Driver");
491 MODULE_LICENSE("GPL");