Commit | Line | Data |
---|---|---|
bf4994d7 SW |
1 | /* |
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> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
bf4994d7 SW |
28 | |
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 | ||
3760f736 | 45 | static const struct i2c_device_id ds1374_id[] = { |
f2eb4327 | 46 | { "ds1374", 0 }, |
3760f736 JD |
47 | { } |
48 | }; | |
49 | MODULE_DEVICE_TABLE(i2c, ds1374_id); | |
50 | ||
bf4994d7 SW |
51 | struct 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 | ||
64 | static struct i2c_driver ds1374_driver; | |
65 | ||
66 | static 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 | ||
91 | static 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 | ||
110 | static 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 | ||
143 | static 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 | ||
156 | static 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 | */ | |
169 | static 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 | ||
b42f9317 | 177 | if (client->irq <= 0) |
bf4994d7 SW |
178 | 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 | ||
202 | out: | |
203 | mutex_unlock(&ds1374->mutex); | |
204 | return ret; | |
205 | } | |
206 | ||
207 | static 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 | ||
b42f9317 | 216 | if (client->irq <= 0) |
bf4994d7 SW |
217 | 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 | ||
bf4994d7 SW |
226 | /* 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 | */ | |
fa7af8b1 | 232 | if (time_before_eq(new_alarm, itime)) |
bf4994d7 | 233 | new_alarm = 1; |
fa7af8b1 RK |
234 | else |
235 | new_alarm -= itime; | |
bf4994d7 SW |
236 | |
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 | ||
262 | out: | |
263 | mutex_unlock(&ds1374->mutex); | |
264 | return ret; | |
265 | } | |
266 | ||
267 | static 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 | ||
277 | static 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) | |
28df30e6 | 287 | goto unlock; |
bf4994d7 SW |
288 | |
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 | ||
bf4994d7 | 300 | rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF); |
bf4994d7 SW |
301 | } |
302 | ||
303 | out: | |
304 | if (!ds1374->exiting) | |
305 | enable_irq(client->irq); | |
28df30e6 | 306 | unlock: |
bf4994d7 SW |
307 | mutex_unlock(&ds1374->mutex); |
308 | } | |
309 | ||
310 | static int ds1374_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) | |
311 | { | |
312 | struct i2c_client *client = to_i2c_client(dev); | |
313 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
314 | int ret = -ENOIOCTLCMD; | |
315 | ||
316 | mutex_lock(&ds1374->mutex); | |
317 | ||
318 | switch (cmd) { | |
319 | case RTC_AIE_OFF: | |
320 | ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
321 | if (ret < 0) | |
322 | goto out; | |
323 | ||
324 | ret &= ~DS1374_REG_CR_WACE; | |
325 | ||
326 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); | |
327 | if (ret < 0) | |
328 | goto out; | |
329 | ||
330 | break; | |
331 | ||
332 | case RTC_AIE_ON: | |
333 | ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
334 | if (ret < 0) | |
335 | goto out; | |
336 | ||
337 | ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE; | |
338 | ret &= ~DS1374_REG_CR_WDALM; | |
339 | ||
340 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); | |
341 | if (ret < 0) | |
342 | goto out; | |
343 | ||
344 | break; | |
345 | } | |
346 | ||
347 | out: | |
348 | mutex_unlock(&ds1374->mutex); | |
349 | return ret; | |
350 | } | |
351 | ||
352 | static const struct rtc_class_ops ds1374_rtc_ops = { | |
353 | .read_time = ds1374_read_time, | |
354 | .set_time = ds1374_set_time, | |
355 | .read_alarm = ds1374_read_alarm, | |
356 | .set_alarm = ds1374_set_alarm, | |
357 | .ioctl = ds1374_ioctl, | |
358 | }; | |
359 | ||
d2653e92 JD |
360 | static int ds1374_probe(struct i2c_client *client, |
361 | const struct i2c_device_id *id) | |
bf4994d7 SW |
362 | { |
363 | struct ds1374 *ds1374; | |
364 | int ret; | |
365 | ||
366 | ds1374 = kzalloc(sizeof(struct ds1374), GFP_KERNEL); | |
367 | if (!ds1374) | |
368 | return -ENOMEM; | |
369 | ||
370 | ds1374->client = client; | |
371 | i2c_set_clientdata(client, ds1374); | |
372 | ||
373 | INIT_WORK(&ds1374->work, ds1374_work); | |
374 | mutex_init(&ds1374->mutex); | |
375 | ||
376 | ret = ds1374_check_rtc_status(client); | |
377 | if (ret) | |
378 | goto out_free; | |
379 | ||
b42f9317 | 380 | if (client->irq > 0) { |
bf4994d7 SW |
381 | ret = request_irq(client->irq, ds1374_irq, 0, |
382 | "ds1374", client); | |
383 | if (ret) { | |
384 | dev_err(&client->dev, "unable to request IRQ\n"); | |
385 | goto out_free; | |
386 | } | |
26b3c01f AV |
387 | |
388 | device_set_wakeup_capable(&client->dev, 1); | |
bf4994d7 SW |
389 | } |
390 | ||
391 | ds1374->rtc = rtc_device_register(client->name, &client->dev, | |
392 | &ds1374_rtc_ops, THIS_MODULE); | |
393 | if (IS_ERR(ds1374->rtc)) { | |
394 | ret = PTR_ERR(ds1374->rtc); | |
395 | dev_err(&client->dev, "unable to register the class device\n"); | |
396 | goto out_irq; | |
397 | } | |
398 | ||
399 | return 0; | |
400 | ||
401 | out_irq: | |
b42f9317 | 402 | if (client->irq > 0) |
bf4994d7 SW |
403 | free_irq(client->irq, client); |
404 | ||
405 | out_free: | |
406 | i2c_set_clientdata(client, NULL); | |
407 | kfree(ds1374); | |
408 | return ret; | |
409 | } | |
410 | ||
411 | static int __devexit ds1374_remove(struct i2c_client *client) | |
412 | { | |
413 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
414 | ||
b42f9317 | 415 | if (client->irq > 0) { |
bf4994d7 SW |
416 | mutex_lock(&ds1374->mutex); |
417 | ds1374->exiting = 1; | |
418 | mutex_unlock(&ds1374->mutex); | |
419 | ||
420 | free_irq(client->irq, client); | |
421 | flush_scheduled_work(); | |
422 | } | |
423 | ||
424 | rtc_device_unregister(ds1374->rtc); | |
425 | i2c_set_clientdata(client, NULL); | |
426 | kfree(ds1374); | |
427 | return 0; | |
428 | } | |
429 | ||
986e36a5 MP |
430 | #ifdef CONFIG_PM |
431 | static int ds1374_suspend(struct i2c_client *client, pm_message_t state) | |
432 | { | |
433 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) | |
434 | enable_irq_wake(client->irq); | |
435 | return 0; | |
436 | } | |
437 | ||
438 | static int ds1374_resume(struct i2c_client *client) | |
439 | { | |
440 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) | |
441 | disable_irq_wake(client->irq); | |
442 | return 0; | |
443 | } | |
444 | #else | |
445 | #define ds1374_suspend NULL | |
446 | #define ds1374_resume NULL | |
447 | #endif | |
448 | ||
bf4994d7 SW |
449 | static struct i2c_driver ds1374_driver = { |
450 | .driver = { | |
451 | .name = "rtc-ds1374", | |
452 | .owner = THIS_MODULE, | |
453 | }, | |
454 | .probe = ds1374_probe, | |
986e36a5 MP |
455 | .suspend = ds1374_suspend, |
456 | .resume = ds1374_resume, | |
bf4994d7 | 457 | .remove = __devexit_p(ds1374_remove), |
3760f736 | 458 | .id_table = ds1374_id, |
bf4994d7 SW |
459 | }; |
460 | ||
461 | static int __init ds1374_init(void) | |
462 | { | |
463 | return i2c_add_driver(&ds1374_driver); | |
464 | } | |
465 | ||
466 | static void __exit ds1374_exit(void) | |
467 | { | |
468 | i2c_del_driver(&ds1374_driver); | |
469 | } | |
470 | ||
471 | module_init(ds1374_init); | |
472 | module_exit(ds1374_exit); | |
473 | ||
474 | MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>"); | |
475 | MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver"); | |
476 | MODULE_LICENSE("GPL"); |