blob: d834a63ec4b0ec9b5c035e480e969f6722a82c7c [file] [log] [blame]
Scott Woodbf4994d2007-10-16 01:28:19 -07001/*
2 * RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
3 *
4 * Based on code by Randy Vinson <rvinson@mvista.com>,
5 * which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
6 *
7 * Copyright (C) 2006-2007 Freescale Semiconductor
8 *
9 * 2005 (c) MontaVista Software, Inc. This file is licensed under
10 * the terms of the GNU General Public License version 2. This program
11 * is licensed "as is" without any warranty of any kind, whether express
12 * or implied.
13 */
14/*
15 * It would be more efficient to use i2c msgs/i2c_transfer directly but, as
16 * recommened in .../Documentation/i2c/writing-clients section
17 * "Sending and receiving", using SMBus level communication is preferred.
18 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/interrupt.h>
23#include <linux/i2c.h>
24#include <linux/rtc.h>
25#include <linux/bcd.h>
26#include <linux/workqueue.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090027#include <linux/slab.h>
Scott Woodbf4994d2007-10-16 01:28:19 -070028
29#define DS1374_REG_TOD0 0x00 /* Time of Day */
30#define DS1374_REG_TOD1 0x01
31#define DS1374_REG_TOD2 0x02
32#define DS1374_REG_TOD3 0x03
33#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
34#define DS1374_REG_WDALM1 0x05
35#define DS1374_REG_WDALM2 0x06
36#define DS1374_REG_CR 0x07 /* Control */
37#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
38#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
39#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
40#define DS1374_REG_SR 0x08 /* Status */
41#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
42#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
43#define DS1374_REG_TCR 0x09 /* Trickle Charge */
44
Jean Delvare3760f732008-04-29 23:11:40 +020045static const struct i2c_device_id ds1374_id[] = {
Jean Delvaref2eb4322008-06-05 22:46:18 -070046 { "ds1374", 0 },
Jean Delvare3760f732008-04-29 23:11:40 +020047 { }
48};
49MODULE_DEVICE_TABLE(i2c, ds1374_id);
50
Scott Woodbf4994d2007-10-16 01:28:19 -070051struct ds1374 {
52 struct i2c_client *client;
53 struct rtc_device *rtc;
54 struct work_struct work;
55
56 /* The mutex protects alarm operations, and prevents a race
57 * between the enable_irq() in the workqueue and the free_irq()
58 * in the remove function.
59 */
60 struct mutex mutex;
61 int exiting;
62};
63
64static struct i2c_driver ds1374_driver;
65
66static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
67 int reg, int nbytes)
68{
69 u8 buf[4];
70 int ret;
71 int i;
72
73 if (nbytes > 4) {
74 WARN_ON(1);
75 return -EINVAL;
76 }
77
78 ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
79
80 if (ret < 0)
81 return ret;
82 if (ret < nbytes)
83 return -EIO;
84
85 for (i = nbytes - 1, *time = 0; i >= 0; i--)
86 *time = (*time << 8) | buf[i];
87
88 return 0;
89}
90
91static int ds1374_write_rtc(struct i2c_client *client, u32 time,
92 int reg, int nbytes)
93{
94 u8 buf[4];
95 int i;
96
97 if (nbytes > 4) {
98 WARN_ON(1);
99 return -EINVAL;
100 }
101
102 for (i = 0; i < nbytes; i++) {
103 buf[i] = time & 0xff;
104 time >>= 8;
105 }
106
107 return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
108}
109
110static int ds1374_check_rtc_status(struct i2c_client *client)
111{
112 int ret = 0;
113 int control, stat;
114
115 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
116 if (stat < 0)
117 return stat;
118
119 if (stat & DS1374_REG_SR_OSF)
120 dev_warn(&client->dev,
121 "oscillator discontinuity flagged, "
122 "time unreliable\n");
123
124 stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
125
126 ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
127 if (ret < 0)
128 return ret;
129
130 /* If the alarm is pending, clear it before requesting
131 * the interrupt, so an interrupt event isn't reported
132 * before everything is initialized.
133 */
134
135 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
136 if (control < 0)
137 return control;
138
139 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
140 return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
141}
142
143static int ds1374_read_time(struct device *dev, struct rtc_time *time)
144{
145 struct i2c_client *client = to_i2c_client(dev);
146 u32 itime;
147 int ret;
148
149 ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
150 if (!ret)
151 rtc_time_to_tm(itime, time);
152
153 return ret;
154}
155
156static int ds1374_set_time(struct device *dev, struct rtc_time *time)
157{
158 struct i2c_client *client = to_i2c_client(dev);
159 unsigned long itime;
160
161 rtc_tm_to_time(time, &itime);
162 return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
163}
164
165/* The ds1374 has a decrementer for an alarm, rather than a comparator.
166 * If the time of day is changed, then the alarm will need to be
167 * reset.
168 */
169static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
170{
171 struct i2c_client *client = to_i2c_client(dev);
172 struct ds1374 *ds1374 = i2c_get_clientdata(client);
173 u32 now, cur_alarm;
174 int cr, sr;
175 int ret = 0;
176
Anton Vorontsovb42f9312008-08-20 14:09:21 -0700177 if (client->irq <= 0)
Scott Woodbf4994d2007-10-16 01:28:19 -0700178 return -EINVAL;
179
180 mutex_lock(&ds1374->mutex);
181
182 cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
183 if (ret < 0)
184 goto out;
185
186 sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
187 if (ret < 0)
188 goto out;
189
190 ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
191 if (ret)
192 goto out;
193
194 ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
195 if (ret)
196 goto out;
197
198 rtc_time_to_tm(now + cur_alarm, &alarm->time);
199 alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
200 alarm->pending = !!(sr & DS1374_REG_SR_AF);
201
202out:
203 mutex_unlock(&ds1374->mutex);
204 return ret;
205}
206
207static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
208{
209 struct i2c_client *client = to_i2c_client(dev);
210 struct ds1374 *ds1374 = i2c_get_clientdata(client);
211 struct rtc_time now;
212 unsigned long new_alarm, itime;
213 int cr;
214 int ret = 0;
215
Anton Vorontsovb42f9312008-08-20 14:09:21 -0700216 if (client->irq <= 0)
Scott Woodbf4994d2007-10-16 01:28:19 -0700217 return -EINVAL;
218
219 ret = ds1374_read_time(dev, &now);
220 if (ret < 0)
221 return ret;
222
223 rtc_tm_to_time(&alarm->time, &new_alarm);
224 rtc_tm_to_time(&now, &itime);
225
Scott Woodbf4994d2007-10-16 01:28:19 -0700226 /* This can happen due to races, in addition to dates that are
227 * truly in the past. To avoid requiring the caller to check for
228 * races, dates in the past are assumed to be in the recent past
229 * (i.e. not something that we'd rather the caller know about via
230 * an error), and the alarm is set to go off as soon as possible.
231 */
Roel Kluinfa7af8b2009-03-31 15:25:00 -0700232 if (time_before_eq(new_alarm, itime))
Scott Woodbf4994d2007-10-16 01:28:19 -0700233 new_alarm = 1;
Roel Kluinfa7af8b2009-03-31 15:25:00 -0700234 else
235 new_alarm -= itime;
Scott Woodbf4994d2007-10-16 01:28:19 -0700236
237 mutex_lock(&ds1374->mutex);
238
239 ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
240 if (ret < 0)
241 goto out;
242
243 /* Disable any existing alarm before setting the new one
244 * (or lack thereof). */
245 cr &= ~DS1374_REG_CR_WACE;
246
247 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
248 if (ret < 0)
249 goto out;
250
251 ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
252 if (ret)
253 goto out;
254
255 if (alarm->enabled) {
256 cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
257 cr &= ~DS1374_REG_CR_WDALM;
258
259 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
260 }
261
262out:
263 mutex_unlock(&ds1374->mutex);
264 return ret;
265}
266
267static irqreturn_t ds1374_irq(int irq, void *dev_id)
268{
269 struct i2c_client *client = dev_id;
270 struct ds1374 *ds1374 = i2c_get_clientdata(client);
271
272 disable_irq_nosync(irq);
273 schedule_work(&ds1374->work);
274 return IRQ_HANDLED;
275}
276
277static void ds1374_work(struct work_struct *work)
278{
279 struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
280 struct i2c_client *client = ds1374->client;
281 int stat, control;
282
283 mutex_lock(&ds1374->mutex);
284
285 stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
286 if (stat < 0)
Jiri Slaby28df30e2009-07-05 12:08:03 -0700287 goto unlock;
Scott Woodbf4994d2007-10-16 01:28:19 -0700288
289 if (stat & DS1374_REG_SR_AF) {
290 stat &= ~DS1374_REG_SR_AF;
291 i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
292
293 control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
294 if (control < 0)
295 goto out;
296
297 control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
298 i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
299
Scott Woodbf4994d2007-10-16 01:28:19 -0700300 rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
Scott Woodbf4994d2007-10-16 01:28:19 -0700301 }
302
303out:
304 if (!ds1374->exiting)
305 enable_irq(client->irq);
Jiri Slaby28df30e2009-07-05 12:08:03 -0700306unlock:
Scott Woodbf4994d2007-10-16 01:28:19 -0700307 mutex_unlock(&ds1374->mutex);
308}
309
John Stultz16380c12011-02-02 17:02:41 -0800310static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
Scott Woodbf4994d2007-10-16 01:28:19 -0700311{
312 struct i2c_client *client = to_i2c_client(dev);
313 struct ds1374 *ds1374 = i2c_get_clientdata(client);
John Stultz16380c12011-02-02 17:02:41 -0800314 int ret;
Scott Woodbf4994d2007-10-16 01:28:19 -0700315
316 mutex_lock(&ds1374->mutex);
317
John Stultz16380c12011-02-02 17:02:41 -0800318 ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
319 if (ret < 0)
320 goto out;
Scott Woodbf4994d2007-10-16 01:28:19 -0700321
John Stultz16380c12011-02-02 17:02:41 -0800322 if (enabled) {
Scott Woodbf4994d2007-10-16 01:28:19 -0700323 ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
324 ret &= ~DS1374_REG_CR_WDALM;
John Stultz16380c12011-02-02 17:02:41 -0800325 } else {
326 ret &= ~DS1374_REG_CR_WACE;
Scott Woodbf4994d2007-10-16 01:28:19 -0700327 }
John Stultz16380c12011-02-02 17:02:41 -0800328 ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
Scott Woodbf4994d2007-10-16 01:28:19 -0700329
330out:
331 mutex_unlock(&ds1374->mutex);
332 return ret;
333}
334
335static const struct rtc_class_ops ds1374_rtc_ops = {
336 .read_time = ds1374_read_time,
337 .set_time = ds1374_set_time,
338 .read_alarm = ds1374_read_alarm,
339 .set_alarm = ds1374_set_alarm,
John Stultz16380c12011-02-02 17:02:41 -0800340 .alarm_irq_enable = ds1374_alarm_irq_enable,
Scott Woodbf4994d2007-10-16 01:28:19 -0700341};
342
Jean Delvared2653e92008-04-29 23:11:39 +0200343static int ds1374_probe(struct i2c_client *client,
344 const struct i2c_device_id *id)
Scott Woodbf4994d2007-10-16 01:28:19 -0700345{
346 struct ds1374 *ds1374;
347 int ret;
348
349 ds1374 = kzalloc(sizeof(struct ds1374), GFP_KERNEL);
350 if (!ds1374)
351 return -ENOMEM;
352
353 ds1374->client = client;
354 i2c_set_clientdata(client, ds1374);
355
356 INIT_WORK(&ds1374->work, ds1374_work);
357 mutex_init(&ds1374->mutex);
358
359 ret = ds1374_check_rtc_status(client);
360 if (ret)
361 goto out_free;
362
Anton Vorontsovb42f9312008-08-20 14:09:21 -0700363 if (client->irq > 0) {
Scott Woodbf4994d2007-10-16 01:28:19 -0700364 ret = request_irq(client->irq, ds1374_irq, 0,
365 "ds1374", client);
366 if (ret) {
367 dev_err(&client->dev, "unable to request IRQ\n");
368 goto out_free;
369 }
Anton Vorontsov26b3c012009-12-17 15:27:23 -0800370
371 device_set_wakeup_capable(&client->dev, 1);
Scott Woodbf4994d2007-10-16 01:28:19 -0700372 }
373
374 ds1374->rtc = rtc_device_register(client->name, &client->dev,
375 &ds1374_rtc_ops, THIS_MODULE);
376 if (IS_ERR(ds1374->rtc)) {
377 ret = PTR_ERR(ds1374->rtc);
378 dev_err(&client->dev, "unable to register the class device\n");
379 goto out_irq;
380 }
381
382 return 0;
383
384out_irq:
Anton Vorontsovb42f9312008-08-20 14:09:21 -0700385 if (client->irq > 0)
Scott Woodbf4994d2007-10-16 01:28:19 -0700386 free_irq(client->irq, client);
387
388out_free:
Scott Woodbf4994d2007-10-16 01:28:19 -0700389 kfree(ds1374);
390 return ret;
391}
392
393static int __devexit ds1374_remove(struct i2c_client *client)
394{
395 struct ds1374 *ds1374 = i2c_get_clientdata(client);
396
Anton Vorontsovb42f9312008-08-20 14:09:21 -0700397 if (client->irq > 0) {
Scott Woodbf4994d2007-10-16 01:28:19 -0700398 mutex_lock(&ds1374->mutex);
399 ds1374->exiting = 1;
400 mutex_unlock(&ds1374->mutex);
401
402 free_irq(client->irq, client);
Tejun Heo9db89952010-12-24 16:00:17 +0100403 cancel_work_sync(&ds1374->work);
Scott Woodbf4994d2007-10-16 01:28:19 -0700404 }
405
406 rtc_device_unregister(ds1374->rtc);
Scott Woodbf4994d2007-10-16 01:28:19 -0700407 kfree(ds1374);
408 return 0;
409}
410
Marc Pignat986e36a2008-10-15 22:02:56 -0700411#ifdef CONFIG_PM
412static int ds1374_suspend(struct i2c_client *client, pm_message_t state)
413{
414 if (client->irq >= 0 && device_may_wakeup(&client->dev))
415 enable_irq_wake(client->irq);
416 return 0;
417}
418
419static int ds1374_resume(struct i2c_client *client)
420{
421 if (client->irq >= 0 && device_may_wakeup(&client->dev))
422 disable_irq_wake(client->irq);
423 return 0;
424}
425#else
426#define ds1374_suspend NULL
427#define ds1374_resume NULL
428#endif
429
Scott Woodbf4994d2007-10-16 01:28:19 -0700430static struct i2c_driver ds1374_driver = {
431 .driver = {
432 .name = "rtc-ds1374",
433 .owner = THIS_MODULE,
434 },
435 .probe = ds1374_probe,
Marc Pignat986e36a2008-10-15 22:02:56 -0700436 .suspend = ds1374_suspend,
437 .resume = ds1374_resume,
Scott Woodbf4994d2007-10-16 01:28:19 -0700438 .remove = __devexit_p(ds1374_remove),
Jean Delvare3760f732008-04-29 23:11:40 +0200439 .id_table = ds1374_id,
Scott Woodbf4994d2007-10-16 01:28:19 -0700440};
441
442static int __init ds1374_init(void)
443{
444 return i2c_add_driver(&ds1374_driver);
445}
446
447static void __exit ds1374_exit(void)
448{
449 i2c_del_driver(&ds1374_driver);
450}
451
452module_init(ds1374_init);
453module_exit(ds1374_exit);
454
455MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
456MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
457MODULE_LICENSE("GPL");