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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> |
bc96ba74 | 28 | #include <linux/pm.h> |
bf4994d7 SW |
29 | |
30 | #define DS1374_REG_TOD0 0x00 /* Time of Day */ | |
31 | #define DS1374_REG_TOD1 0x01 | |
32 | #define DS1374_REG_TOD2 0x02 | |
33 | #define DS1374_REG_TOD3 0x03 | |
34 | #define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */ | |
35 | #define DS1374_REG_WDALM1 0x05 | |
36 | #define DS1374_REG_WDALM2 0x06 | |
37 | #define DS1374_REG_CR 0x07 /* Control */ | |
38 | #define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */ | |
39 | #define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */ | |
40 | #define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */ | |
41 | #define DS1374_REG_SR 0x08 /* Status */ | |
42 | #define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */ | |
43 | #define DS1374_REG_SR_AF 0x01 /* Alarm Flag */ | |
44 | #define DS1374_REG_TCR 0x09 /* Trickle Charge */ | |
45 | ||
3760f736 | 46 | static const struct i2c_device_id ds1374_id[] = { |
f2eb4327 | 47 | { "ds1374", 0 }, |
3760f736 JD |
48 | { } |
49 | }; | |
50 | MODULE_DEVICE_TABLE(i2c, ds1374_id); | |
51 | ||
bf4994d7 SW |
52 | struct ds1374 { |
53 | struct i2c_client *client; | |
54 | struct rtc_device *rtc; | |
55 | struct work_struct work; | |
56 | ||
57 | /* The mutex protects alarm operations, and prevents a race | |
58 | * between the enable_irq() in the workqueue and the free_irq() | |
59 | * in the remove function. | |
60 | */ | |
61 | struct mutex mutex; | |
62 | int exiting; | |
63 | }; | |
64 | ||
65 | static struct i2c_driver ds1374_driver; | |
66 | ||
67 | static int ds1374_read_rtc(struct i2c_client *client, u32 *time, | |
adc7b9b6 | 68 | int reg, int nbytes) |
bf4994d7 SW |
69 | { |
70 | u8 buf[4]; | |
71 | int ret; | |
72 | int i; | |
73 | ||
74 | if (nbytes > 4) { | |
75 | WARN_ON(1); | |
76 | return -EINVAL; | |
77 | } | |
78 | ||
79 | ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf); | |
80 | ||
81 | if (ret < 0) | |
82 | return ret; | |
83 | if (ret < nbytes) | |
84 | return -EIO; | |
85 | ||
86 | for (i = nbytes - 1, *time = 0; i >= 0; i--) | |
87 | *time = (*time << 8) | buf[i]; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | static int ds1374_write_rtc(struct i2c_client *client, u32 time, | |
adc7b9b6 | 93 | int reg, int nbytes) |
bf4994d7 SW |
94 | { |
95 | u8 buf[4]; | |
96 | int i; | |
97 | ||
98 | if (nbytes > 4) { | |
99 | WARN_ON(1); | |
100 | return -EINVAL; | |
101 | } | |
102 | ||
103 | for (i = 0; i < nbytes; i++) { | |
104 | buf[i] = time & 0xff; | |
105 | time >>= 8; | |
106 | } | |
107 | ||
108 | return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf); | |
109 | } | |
110 | ||
111 | static int ds1374_check_rtc_status(struct i2c_client *client) | |
112 | { | |
113 | int ret = 0; | |
114 | int control, stat; | |
115 | ||
116 | stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR); | |
117 | if (stat < 0) | |
118 | return stat; | |
119 | ||
120 | if (stat & DS1374_REG_SR_OSF) | |
121 | dev_warn(&client->dev, | |
adc7b9b6 | 122 | "oscillator discontinuity flagged, time unreliable\n"); |
bf4994d7 SW |
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 | ||
16380c15 | 310 | static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled) |
bf4994d7 SW |
311 | { |
312 | struct i2c_client *client = to_i2c_client(dev); | |
313 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
16380c15 | 314 | int ret; |
bf4994d7 SW |
315 | |
316 | mutex_lock(&ds1374->mutex); | |
317 | ||
16380c15 JS |
318 | ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR); |
319 | if (ret < 0) | |
320 | goto out; | |
bf4994d7 | 321 | |
16380c15 | 322 | if (enabled) { |
bf4994d7 SW |
323 | ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE; |
324 | ret &= ~DS1374_REG_CR_WDALM; | |
16380c15 JS |
325 | } else { |
326 | ret &= ~DS1374_REG_CR_WACE; | |
bf4994d7 | 327 | } |
16380c15 | 328 | ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret); |
bf4994d7 SW |
329 | |
330 | out: | |
331 | mutex_unlock(&ds1374->mutex); | |
332 | return ret; | |
333 | } | |
334 | ||
335 | static 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, | |
16380c15 | 340 | .alarm_irq_enable = ds1374_alarm_irq_enable, |
bf4994d7 SW |
341 | }; |
342 | ||
d2653e92 JD |
343 | static int ds1374_probe(struct i2c_client *client, |
344 | const struct i2c_device_id *id) | |
bf4994d7 SW |
345 | { |
346 | struct ds1374 *ds1374; | |
347 | int ret; | |
348 | ||
d1a96639 | 349 | ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL); |
bf4994d7 SW |
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) | |
d1a96639 | 361 | return ret; |
bf4994d7 | 362 | |
b42f9317 | 363 | if (client->irq > 0) { |
d1a96639 | 364 | ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0, |
adc7b9b6 | 365 | "ds1374", client); |
bf4994d7 SW |
366 | if (ret) { |
367 | dev_err(&client->dev, "unable to request IRQ\n"); | |
d1a96639 | 368 | return ret; |
bf4994d7 | 369 | } |
26b3c01f AV |
370 | |
371 | device_set_wakeup_capable(&client->dev, 1); | |
bf4994d7 SW |
372 | } |
373 | ||
d1a96639 | 374 | ds1374->rtc = devm_rtc_device_register(&client->dev, client->name, |
adc7b9b6 | 375 | &ds1374_rtc_ops, THIS_MODULE); |
bf4994d7 | 376 | if (IS_ERR(ds1374->rtc)) { |
bf4994d7 | 377 | dev_err(&client->dev, "unable to register the class device\n"); |
d1a96639 | 378 | return PTR_ERR(ds1374->rtc); |
bf4994d7 SW |
379 | } |
380 | ||
381 | return 0; | |
bf4994d7 SW |
382 | } |
383 | ||
5a167f45 | 384 | static int ds1374_remove(struct i2c_client *client) |
bf4994d7 SW |
385 | { |
386 | struct ds1374 *ds1374 = i2c_get_clientdata(client); | |
387 | ||
b42f9317 | 388 | if (client->irq > 0) { |
bf4994d7 SW |
389 | mutex_lock(&ds1374->mutex); |
390 | ds1374->exiting = 1; | |
391 | mutex_unlock(&ds1374->mutex); | |
392 | ||
d1a96639 | 393 | devm_free_irq(&client->dev, client->irq, client); |
9db8995b | 394 | cancel_work_sync(&ds1374->work); |
bf4994d7 SW |
395 | } |
396 | ||
bf4994d7 SW |
397 | return 0; |
398 | } | |
399 | ||
8b80ef64 | 400 | #ifdef CONFIG_PM_SLEEP |
bc96ba74 | 401 | static int ds1374_suspend(struct device *dev) |
986e36a5 | 402 | { |
bc96ba74 MB |
403 | struct i2c_client *client = to_i2c_client(dev); |
404 | ||
986e36a5 MP |
405 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) |
406 | enable_irq_wake(client->irq); | |
407 | return 0; | |
408 | } | |
409 | ||
bc96ba74 | 410 | static int ds1374_resume(struct device *dev) |
986e36a5 | 411 | { |
bc96ba74 MB |
412 | struct i2c_client *client = to_i2c_client(dev); |
413 | ||
986e36a5 MP |
414 | if (client->irq >= 0 && device_may_wakeup(&client->dev)) |
415 | disable_irq_wake(client->irq); | |
416 | return 0; | |
417 | } | |
8b80ef64 | 418 | #endif |
bc96ba74 MB |
419 | |
420 | static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume); | |
421 | ||
bf4994d7 SW |
422 | static struct i2c_driver ds1374_driver = { |
423 | .driver = { | |
424 | .name = "rtc-ds1374", | |
425 | .owner = THIS_MODULE, | |
8b80ef64 | 426 | .pm = &ds1374_pm, |
bf4994d7 SW |
427 | }, |
428 | .probe = ds1374_probe, | |
5a167f45 | 429 | .remove = ds1374_remove, |
3760f736 | 430 | .id_table = ds1374_id, |
bf4994d7 SW |
431 | }; |
432 | ||
0abc9201 | 433 | module_i2c_driver(ds1374_driver); |
bf4994d7 SW |
434 | |
435 | MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>"); | |
436 | MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver"); | |
437 | MODULE_LICENSE("GPL"); |