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> | |
27 | ||
28 | #define DS1374_REG_TOD0 0x00 /* Time of Day */ | |
29 | #define DS1374_REG_TOD1 0x01 | |
30 | #define DS1374_REG_TOD2 0x02 | |
31 | #define DS1374_REG_TOD3 0x03 | |
32 | #define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */ | |
33 | #define DS1374_REG_WDALM1 0x05 | |
34 | #define DS1374_REG_WDALM2 0x06 | |
35 | #define DS1374_REG_CR 0x07 /* Control */ | |
36 | #define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */ | |
37 | #define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */ | |
38 | #define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */ | |
39 | #define DS1374_REG_SR 0x08 /* Status */ | |
40 | #define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */ | |
41 | #define DS1374_REG_SR_AF 0x01 /* Alarm Flag */ | |
42 | #define DS1374_REG_TCR 0x09 /* Trickle Charge */ | |
43 | ||
3760f736 | 44 | static const struct i2c_device_id ds1374_id[] = { |
f2eb4327 | 45 | { "ds1374", 0 }, |
3760f736 JD |
46 | { } |
47 | }; | |
48 | MODULE_DEVICE_TABLE(i2c, ds1374_id); | |
49 | ||
bf4994d7 SW |
50 | struct ds1374 { |
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; | |
60 | int exiting; | |
61 | }; | |
62 | ||
63 | static struct i2c_driver ds1374_driver; | |
64 | ||
65 | static int ds1374_read_rtc(struct i2c_client *client, u32 *time, | |
66 | int reg, int nbytes) | |
67 | { | |
68 | u8 buf[4]; | |
69 | int ret; | |
70 | int i; | |
71 | ||
72 | if (nbytes > 4) { | |
73 | WARN_ON(1); | |
74 | return -EINVAL; | |
75 | } | |
76 | ||
77 | ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf); | |
78 | ||
79 | if (ret < 0) | |
80 | return ret; | |
81 | if (ret < nbytes) | |
82 | return -EIO; | |
83 | ||
84 | for (i = nbytes - 1, *time = 0; i >= 0; i--) | |
85 | *time = (*time << 8) | buf[i]; | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static int ds1374_write_rtc(struct i2c_client *client, u32 time, | |
91 | int reg, int nbytes) | |
92 | { | |
93 | u8 buf[4]; | |
94 | int i; | |
95 | ||
96 | if (nbytes > 4) { | |
97 | WARN_ON(1); | |
98 | return -EINVAL; | |
99 | } | |
100 | ||
101 | for (i = 0; i < nbytes; i++) { | |
102 | buf[i] = time & 0xff; | |
103 | time >>= 8; | |
104 | } | |
105 | ||
106 | return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf); | |
107 | } | |
108 | ||
109 | static int ds1374_check_rtc_status(struct i2c_client *client) | |
110 | { | |
111 | int ret = 0; | |
112 | int control, stat; | |
113 | ||
114 | stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR); | |
115 | if (stat < 0) | |
116 | return stat; | |
117 | ||
118 | if (stat & DS1374_REG_SR_OSF) | |
119 | dev_warn(&client->dev, | |
120 | "oscillator discontinuity flagged, " | |
121 | "time unreliable\n"); | |
122 | ||
123 | stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF); | |
124 | ||
125 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat); | |
126 | if (ret < 0) | |
127 | return ret; | |
128 | ||
129 | /* If the alarm is pending, clear it before requesting | |
130 | * the interrupt, so an interrupt event isn't reported | |
131 | * before everything is initialized. | |
132 | */ | |
133 | ||
134 | control = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
135 | if (control < 0) | |
136 | return control; | |
137 | ||
138 | control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE); | |
139 | return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control); | |
140 | } | |
141 | ||
142 | static int ds1374_read_time(struct device *dev, struct rtc_time *time) | |
143 | { | |
144 | struct i2c_client *client = to_i2c_client(dev); | |
145 | u32 itime; | |
146 | int ret; | |
147 | ||
148 | ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4); | |
149 | if (!ret) | |
150 | rtc_time_to_tm(itime, time); | |
151 | ||
152 | return ret; | |
153 | } | |
154 | ||
155 | static int ds1374_set_time(struct device *dev, struct rtc_time *time) | |
156 | { | |
157 | struct i2c_client *client = to_i2c_client(dev); | |
158 | unsigned long itime; | |
159 | ||
160 | rtc_tm_to_time(time, &itime); | |
161 | return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4); | |
162 | } | |
163 | ||
164 | /* The ds1374 has a decrementer for an alarm, rather than a comparator. | |
165 | * If the time of day is changed, then the alarm will need to be | |
166 | * reset. | |
167 | */ | |
168 | static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
169 | { | |
170 | struct i2c_client *client = to_i2c_client(dev); | |
171 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
172 | u32 now, cur_alarm; | |
173 | int cr, sr; | |
174 | int ret = 0; | |
175 | ||
b42f9317 | 176 | if (client->irq <= 0) |
bf4994d7 SW |
177 | return -EINVAL; |
178 | ||
179 | mutex_lock(&ds1374->mutex); | |
180 | ||
181 | cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
182 | if (ret < 0) | |
183 | goto out; | |
184 | ||
185 | sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR); | |
186 | if (ret < 0) | |
187 | goto out; | |
188 | ||
189 | ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4); | |
190 | if (ret) | |
191 | goto out; | |
192 | ||
193 | ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3); | |
194 | if (ret) | |
195 | goto out; | |
196 | ||
197 | rtc_time_to_tm(now + cur_alarm, &alarm->time); | |
198 | alarm->enabled = !!(cr & DS1374_REG_CR_WACE); | |
199 | alarm->pending = !!(sr & DS1374_REG_SR_AF); | |
200 | ||
201 | out: | |
202 | mutex_unlock(&ds1374->mutex); | |
203 | return ret; | |
204 | } | |
205 | ||
206 | static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
207 | { | |
208 | struct i2c_client *client = to_i2c_client(dev); | |
209 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
210 | struct rtc_time now; | |
211 | unsigned long new_alarm, itime; | |
212 | int cr; | |
213 | int ret = 0; | |
214 | ||
b42f9317 | 215 | if (client->irq <= 0) |
bf4994d7 SW |
216 | return -EINVAL; |
217 | ||
218 | ret = ds1374_read_time(dev, &now); | |
219 | if (ret < 0) | |
220 | return ret; | |
221 | ||
222 | rtc_tm_to_time(&alarm->time, &new_alarm); | |
223 | rtc_tm_to_time(&now, &itime); | |
224 | ||
bf4994d7 SW |
225 | /* This can happen due to races, in addition to dates that are |
226 | * truly in the past. To avoid requiring the caller to check for | |
227 | * races, dates in the past are assumed to be in the recent past | |
228 | * (i.e. not something that we'd rather the caller know about via | |
229 | * an error), and the alarm is set to go off as soon as possible. | |
230 | */ | |
fa7af8b1 | 231 | if (time_before_eq(new_alarm, itime)) |
bf4994d7 | 232 | new_alarm = 1; |
fa7af8b1 RK |
233 | else |
234 | new_alarm -= itime; | |
bf4994d7 SW |
235 | |
236 | mutex_lock(&ds1374->mutex); | |
237 | ||
238 | ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
239 | if (ret < 0) | |
240 | goto out; | |
241 | ||
242 | /* Disable any existing alarm before setting the new one | |
243 | * (or lack thereof). */ | |
244 | cr &= ~DS1374_REG_CR_WACE; | |
245 | ||
246 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr); | |
247 | if (ret < 0) | |
248 | goto out; | |
249 | ||
250 | ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3); | |
251 | if (ret) | |
252 | goto out; | |
253 | ||
254 | if (alarm->enabled) { | |
255 | cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE; | |
256 | cr &= ~DS1374_REG_CR_WDALM; | |
257 | ||
258 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr); | |
259 | } | |
260 | ||
261 | out: | |
262 | mutex_unlock(&ds1374->mutex); | |
263 | return ret; | |
264 | } | |
265 | ||
266 | static irqreturn_t ds1374_irq(int irq, void *dev_id) | |
267 | { | |
268 | struct i2c_client *client = dev_id; | |
269 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
270 | ||
271 | disable_irq_nosync(irq); | |
272 | schedule_work(&ds1374->work); | |
273 | return IRQ_HANDLED; | |
274 | } | |
275 | ||
276 | static void ds1374_work(struct work_struct *work) | |
277 | { | |
278 | struct ds1374 *ds1374 = container_of(work, struct ds1374, work); | |
279 | struct i2c_client *client = ds1374->client; | |
280 | int stat, control; | |
281 | ||
282 | mutex_lock(&ds1374->mutex); | |
283 | ||
284 | stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR); | |
285 | if (stat < 0) | |
28df30e6 | 286 | goto unlock; |
bf4994d7 SW |
287 | |
288 | if (stat & DS1374_REG_SR_AF) { | |
289 | stat &= ~DS1374_REG_SR_AF; | |
290 | i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat); | |
291 | ||
292 | control = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
293 | if (control < 0) | |
294 | goto out; | |
295 | ||
296 | control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE); | |
297 | i2c_smbus_write_byte_data(client, DS1374_REG_CR, control); | |
298 | ||
bf4994d7 | 299 | rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF); |
bf4994d7 SW |
300 | } |
301 | ||
302 | out: | |
303 | if (!ds1374->exiting) | |
304 | enable_irq(client->irq); | |
28df30e6 | 305 | unlock: |
bf4994d7 SW |
306 | mutex_unlock(&ds1374->mutex); |
307 | } | |
308 | ||
309 | static int ds1374_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) | |
310 | { | |
311 | struct i2c_client *client = to_i2c_client(dev); | |
312 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
313 | int ret = -ENOIOCTLCMD; | |
314 | ||
315 | mutex_lock(&ds1374->mutex); | |
316 | ||
317 | switch (cmd) { | |
318 | case RTC_AIE_OFF: | |
319 | ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
320 | if (ret < 0) | |
321 | goto out; | |
322 | ||
323 | ret &= ~DS1374_REG_CR_WACE; | |
324 | ||
325 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); | |
326 | if (ret < 0) | |
327 | goto out; | |
328 | ||
329 | break; | |
330 | ||
331 | case RTC_AIE_ON: | |
332 | ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); | |
333 | if (ret < 0) | |
334 | goto out; | |
335 | ||
336 | ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE; | |
337 | ret &= ~DS1374_REG_CR_WDALM; | |
338 | ||
339 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); | |
340 | if (ret < 0) | |
341 | goto out; | |
342 | ||
343 | break; | |
344 | } | |
345 | ||
346 | out: | |
347 | mutex_unlock(&ds1374->mutex); | |
348 | return ret; | |
349 | } | |
350 | ||
351 | static const struct rtc_class_ops ds1374_rtc_ops = { | |
352 | .read_time = ds1374_read_time, | |
353 | .set_time = ds1374_set_time, | |
354 | .read_alarm = ds1374_read_alarm, | |
355 | .set_alarm = ds1374_set_alarm, | |
356 | .ioctl = ds1374_ioctl, | |
357 | }; | |
358 | ||
d2653e92 JD |
359 | static int ds1374_probe(struct i2c_client *client, |
360 | const struct i2c_device_id *id) | |
bf4994d7 SW |
361 | { |
362 | struct ds1374 *ds1374; | |
363 | int ret; | |
364 | ||
365 | ds1374 = kzalloc(sizeof(struct ds1374), GFP_KERNEL); | |
366 | if (!ds1374) | |
367 | return -ENOMEM; | |
368 | ||
369 | ds1374->client = client; | |
370 | i2c_set_clientdata(client, ds1374); | |
371 | ||
372 | INIT_WORK(&ds1374->work, ds1374_work); | |
373 | mutex_init(&ds1374->mutex); | |
374 | ||
375 | ret = ds1374_check_rtc_status(client); | |
376 | if (ret) | |
377 | goto out_free; | |
378 | ||
b42f9317 | 379 | if (client->irq > 0) { |
bf4994d7 SW |
380 | ret = request_irq(client->irq, ds1374_irq, 0, |
381 | "ds1374", client); | |
382 | if (ret) { | |
383 | dev_err(&client->dev, "unable to request IRQ\n"); | |
384 | goto out_free; | |
385 | } | |
386 | } | |
387 | ||
388 | ds1374->rtc = rtc_device_register(client->name, &client->dev, | |
389 | &ds1374_rtc_ops, THIS_MODULE); | |
390 | if (IS_ERR(ds1374->rtc)) { | |
391 | ret = PTR_ERR(ds1374->rtc); | |
392 | dev_err(&client->dev, "unable to register the class device\n"); | |
393 | goto out_irq; | |
394 | } | |
395 | ||
396 | return 0; | |
397 | ||
398 | out_irq: | |
b42f9317 | 399 | if (client->irq > 0) |
bf4994d7 SW |
400 | free_irq(client->irq, client); |
401 | ||
402 | out_free: | |
403 | i2c_set_clientdata(client, NULL); | |
404 | kfree(ds1374); | |
405 | return ret; | |
406 | } | |
407 | ||
408 | static int __devexit ds1374_remove(struct i2c_client *client) | |
409 | { | |
410 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
411 | ||
b42f9317 | 412 | if (client->irq > 0) { |
bf4994d7 SW |
413 | mutex_lock(&ds1374->mutex); |
414 | ds1374->exiting = 1; | |
415 | mutex_unlock(&ds1374->mutex); | |
416 | ||
417 | free_irq(client->irq, client); | |
418 | flush_scheduled_work(); | |
419 | } | |
420 | ||
421 | rtc_device_unregister(ds1374->rtc); | |
422 | i2c_set_clientdata(client, NULL); | |
423 | kfree(ds1374); | |
424 | return 0; | |
425 | } | |
426 | ||
986e36a5 MP |
427 | #ifdef CONFIG_PM |
428 | static int ds1374_suspend(struct i2c_client *client, pm_message_t state) | |
429 | { | |
430 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) | |
431 | enable_irq_wake(client->irq); | |
432 | return 0; | |
433 | } | |
434 | ||
435 | static int ds1374_resume(struct i2c_client *client) | |
436 | { | |
437 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) | |
438 | disable_irq_wake(client->irq); | |
439 | return 0; | |
440 | } | |
441 | #else | |
442 | #define ds1374_suspend NULL | |
443 | #define ds1374_resume NULL | |
444 | #endif | |
445 | ||
bf4994d7 SW |
446 | static struct i2c_driver ds1374_driver = { |
447 | .driver = { | |
448 | .name = "rtc-ds1374", | |
449 | .owner = THIS_MODULE, | |
450 | }, | |
451 | .probe = ds1374_probe, | |
986e36a5 MP |
452 | .suspend = ds1374_suspend, |
453 | .resume = ds1374_resume, | |
bf4994d7 | 454 | .remove = __devexit_p(ds1374_remove), |
3760f736 | 455 | .id_table = ds1374_id, |
bf4994d7 SW |
456 | }; |
457 | ||
458 | static int __init ds1374_init(void) | |
459 | { | |
460 | return i2c_add_driver(&ds1374_driver); | |
461 | } | |
462 | ||
463 | static void __exit ds1374_exit(void) | |
464 | { | |
465 | i2c_del_driver(&ds1374_driver); | |
466 | } | |
467 | ||
468 | module_init(ds1374_init); | |
469 | module_exit(ds1374_exit); | |
470 | ||
471 | MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>"); | |
472 | MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver"); | |
473 | MODULE_LICENSE("GPL"); |