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1/*
2 * RTC driver for the Micro Crystal RV8803
3 *
4 * Copyright (C) 2015 Micro Crystal SA
5 *
6 * Alexandre Belloni <alexandre.belloni@free-electrons.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/bcd.h>
15#include <linux/bitops.h>
16#include <linux/i2c.h>
17#include <linux/interrupt.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/rtc.h>
21
22#define RV8803_SEC 0x00
23#define RV8803_MIN 0x01
24#define RV8803_HOUR 0x02
25#define RV8803_WEEK 0x03
26#define RV8803_DAY 0x04
27#define RV8803_MONTH 0x05
28#define RV8803_YEAR 0x06
29#define RV8803_RAM 0x07
30#define RV8803_ALARM_MIN 0x08
31#define RV8803_ALARM_HOUR 0x09
32#define RV8803_ALARM_WEEK_OR_DAY 0x0A
33#define RV8803_EXT 0x0D
34#define RV8803_FLAG 0x0E
35#define RV8803_CTRL 0x0F
36
37#define RV8803_EXT_WADA BIT(6)
38
39#define RV8803_FLAG_V1F BIT(0)
40#define RV8803_FLAG_V2F BIT(1)
41#define RV8803_FLAG_AF BIT(3)
42#define RV8803_FLAG_TF BIT(4)
43#define RV8803_FLAG_UF BIT(5)
44
45#define RV8803_CTRL_RESET BIT(0)
46
47#define RV8803_CTRL_EIE BIT(2)
48#define RV8803_CTRL_AIE BIT(3)
49#define RV8803_CTRL_TIE BIT(4)
50#define RV8803_CTRL_UIE BIT(5)
51
52struct rv8803_data {
53 struct i2c_client *client;
54 struct rtc_device *rtc;
55 struct mutex flags_lock;
56 u8 ctrl;
57};
58
59static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
60{
61 struct i2c_client *client = dev_id;
62 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
63 unsigned long events = 0;
64 int flags, try = 0;
65
66 mutex_lock(&rv8803->flags_lock);
67
68 do {
69 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
70 try++;
71 } while ((flags == -ENXIO) && (try < 3));
72 if (flags <= 0) {
73 mutex_unlock(&rv8803->flags_lock);
74 return IRQ_NONE;
75 }
76
77 if (flags & RV8803_FLAG_V1F)
78 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
79
80 if (flags & RV8803_FLAG_V2F)
81 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
82
83 if (flags & RV8803_FLAG_TF) {
84 flags &= ~RV8803_FLAG_TF;
85 rv8803->ctrl &= ~RV8803_CTRL_TIE;
86 events |= RTC_PF;
87 }
88
89 if (flags & RV8803_FLAG_AF) {
90 flags &= ~RV8803_FLAG_AF;
91 rv8803->ctrl &= ~RV8803_CTRL_AIE;
92 events |= RTC_AF;
93 }
94
95 if (flags & RV8803_FLAG_UF) {
96 flags &= ~RV8803_FLAG_UF;
97 rv8803->ctrl &= ~RV8803_CTRL_UIE;
98 events |= RTC_UF;
99 }
100
101 if (events) {
102 rtc_update_irq(rv8803->rtc, 1, events);
103 i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
104 i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
105 rv8803->ctrl);
106 }
107
108 mutex_unlock(&rv8803->flags_lock);
109
110 return IRQ_HANDLED;
111}
112
113static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
114{
115 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
116 u8 date1[7];
117 u8 date2[7];
118 u8 *date = date1;
119 int ret, flags;
120
121 flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
122 if (flags < 0)
123 return flags;
124
125 if (flags & RV8803_FLAG_V2F) {
126 dev_warn(dev, "Voltage low, data is invalid.\n");
127 return -EINVAL;
128 }
129
130 ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
131 7, date);
132 if (ret != 7)
133 return ret < 0 ? ret : -EIO;
134
135 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
136 ret = i2c_smbus_read_i2c_block_data(rv8803->client, RV8803_SEC,
137 7, date2);
138 if (ret != 7)
139 return ret < 0 ? ret : -EIO;
140
141 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
142 date = date2;
143 }
144
145 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
146 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
147 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
148 tm->tm_wday = ffs(date[RV8803_WEEK] & 0x7f);
149 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
150 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
151 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
152
153 return rtc_valid_tm(tm);
154}
155
156static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
157{
158 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
159 u8 date[7];
160 int flags, ret;
161
162 if ((tm->tm_year < 100) || (tm->tm_year > 199))
163 return -EINVAL;
164
165 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
166 date[RV8803_MIN] = bin2bcd(tm->tm_min);
167 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
168 date[RV8803_WEEK] = 1 << (tm->tm_wday);
169 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
170 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
171 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
172
173 ret = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_SEC,
174 7, date);
175 if (ret < 0)
176 return ret;
177
178 mutex_lock(&rv8803->flags_lock);
179
180 flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
181 if (flags < 0) {
182 mutex_unlock(&rv8803->flags_lock);
183 return flags;
184 }
185
186 ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
187 flags & ~RV8803_FLAG_V2F);
188
189 mutex_unlock(&rv8803->flags_lock);
190
191 return ret;
192}
193
194static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
195{
196 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
197 struct i2c_client *client = rv8803->client;
198 u8 alarmvals[3];
199 int flags, ret;
200
201 ret = i2c_smbus_read_i2c_block_data(client, RV8803_ALARM_MIN,
202 3, alarmvals);
203 if (ret != 3)
204 return ret < 0 ? ret : -EIO;
205
206 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
207 if (flags < 0)
208 return flags;
209
210 alrm->time.tm_sec = 0;
211 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
212 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
213 alrm->time.tm_wday = -1;
214 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
215 alrm->time.tm_mon = -1;
216 alrm->time.tm_year = -1;
217
218 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
219 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
220
221 return 0;
222}
223
224static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
225{
226 struct i2c_client *client = to_i2c_client(dev);
227 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
228 u8 alarmvals[3];
229 u8 ctrl[2];
230 int ret, err;
231
232 /* The alarm has no seconds, round up to nearest minute */
233 if (alrm->time.tm_sec) {
234 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
235
236 alarm_time += 60 - alrm->time.tm_sec;
237 rtc_time64_to_tm(alarm_time, &alrm->time);
238 }
239
240 mutex_lock(&rv8803->flags_lock);
241
242 ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
243 if (ret != 2) {
244 mutex_unlock(&rv8803->flags_lock);
245 return ret < 0 ? ret : -EIO;
246 }
247
248 alarmvals[0] = bin2bcd(alrm->time.tm_min);
249 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
250 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
251
252 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
253 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
254 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
255 rv8803->ctrl);
256 if (err) {
257 mutex_unlock(&rv8803->flags_lock);
258 return err;
259 }
260 }
261
262 ctrl[1] &= ~RV8803_FLAG_AF;
263 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
264 mutex_unlock(&rv8803->flags_lock);
265 if (err)
266 return err;
267
268 err = i2c_smbus_write_i2c_block_data(rv8803->client, RV8803_ALARM_MIN,
269 3, alarmvals);
270 if (err)
271 return err;
272
273 if (alrm->enabled) {
274 if (rv8803->rtc->uie_rtctimer.enabled)
275 rv8803->ctrl |= RV8803_CTRL_UIE;
276 if (rv8803->rtc->aie_timer.enabled)
277 rv8803->ctrl |= RV8803_CTRL_AIE;
278
279 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
280 rv8803->ctrl);
281 if (err)
282 return err;
283 }
284
285 return 0;
286}
287
288static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
289{
290 struct i2c_client *client = to_i2c_client(dev);
291 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
292 int ctrl, flags, err;
293
294 ctrl = rv8803->ctrl;
295
296 if (enabled) {
297 if (rv8803->rtc->uie_rtctimer.enabled)
298 ctrl |= RV8803_CTRL_UIE;
299 if (rv8803->rtc->aie_timer.enabled)
300 ctrl |= RV8803_CTRL_AIE;
301 } else {
302 if (!rv8803->rtc->uie_rtctimer.enabled)
303 ctrl &= ~RV8803_CTRL_UIE;
304 if (!rv8803->rtc->aie_timer.enabled)
305 ctrl &= ~RV8803_CTRL_AIE;
306 }
307
308 mutex_lock(&rv8803->flags_lock);
309 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
310 if (flags < 0) {
311 mutex_unlock(&rv8803->flags_lock);
312 return flags;
313 }
314 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
315 err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
316 mutex_unlock(&rv8803->flags_lock);
317 if (err)
318 return err;
319
320 if (ctrl != rv8803->ctrl) {
321 rv8803->ctrl = ctrl;
322 err = i2c_smbus_write_byte_data(client, RV8803_CTRL,
323 rv8803->ctrl);
324 if (err)
325 return err;
326 }
327
328 return 0;
329}
330
331static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
332{
333 struct i2c_client *client = to_i2c_client(dev);
334 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
335 int flags, ret = 0;
336
337 switch (cmd) {
338 case RTC_VL_READ:
339 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
340 if (flags < 0)
341 return flags;
342
343 if (flags & RV8803_FLAG_V1F)
344 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
345
346 if (flags & RV8803_FLAG_V2F)
347 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
348
349 flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
350
351 if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
352 return -EFAULT;
353
354 return 0;
355
356 case RTC_VL_CLR:
357 mutex_lock(&rv8803->flags_lock);
358 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
359 if (flags < 0) {
360 mutex_unlock(&rv8803->flags_lock);
361 return flags;
362 }
363
364 flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
365 ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
366 mutex_unlock(&rv8803->flags_lock);
367 if (ret < 0)
368 return ret;
369
370 return 0;
371
372 default:
373 return -ENOIOCTLCMD;
374 }
375}
376
377static ssize_t rv8803_nvram_write(struct file *filp, struct kobject *kobj,
378 struct bin_attribute *attr,
379 char *buf, loff_t off, size_t count)
380{
381 struct device *dev = kobj_to_dev(kobj);
382 struct i2c_client *client = to_i2c_client(dev);
383 int ret;
384
385 ret = i2c_smbus_write_byte_data(client, RV8803_RAM, buf[0]);
386 if (ret < 0)
387 return ret;
388
389 return 1;
390}
391
392static ssize_t rv8803_nvram_read(struct file *filp, struct kobject *kobj,
393 struct bin_attribute *attr,
394 char *buf, loff_t off, size_t count)
395{
396 struct device *dev = kobj_to_dev(kobj);
397 struct i2c_client *client = to_i2c_client(dev);
398 int ret;
399
400 ret = i2c_smbus_read_byte_data(client, RV8803_RAM);
401 if (ret < 0)
402 return ret;
403
404 buf[0] = ret;
405
406 return 1;
407}
408
409static struct bin_attribute rv8803_nvram_attr = {
410 .attr = {
411 .name = "nvram",
412 .mode = S_IRUGO | S_IWUSR,
413 },
414 .size = 1,
415 .read = rv8803_nvram_read,
416 .write = rv8803_nvram_write,
417};
418
419static struct rtc_class_ops rv8803_rtc_ops = {
420 .read_time = rv8803_get_time,
421 .set_time = rv8803_set_time,
422 .ioctl = rv8803_ioctl,
423};
424
425static int rv8803_probe(struct i2c_client *client,
426 const struct i2c_device_id *id)
427{
428 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
429 struct rv8803_data *rv8803;
430 int err, flags, try = 0;
431
432 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
433 I2C_FUNC_SMBUS_I2C_BLOCK)) {
434 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
435 return -EIO;
436 }
437
438 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
439 GFP_KERNEL);
440 if (!rv8803)
441 return -ENOMEM;
442
443 mutex_init(&rv8803->flags_lock);
444 rv8803->client = client;
445 i2c_set_clientdata(client, rv8803);
446
447 /*
448 * There is a 60µs window where the RTC may not reply on the i2c bus in
449 * that case, the transfer is not ACKed. In that case, ensure there are
450 * multiple attempts.
451 */
452 do {
453 flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
454 try++;
455 } while ((flags == -ENXIO) && (try < 3));
456
457 if (flags < 0)
458 return flags;
459
460 if (flags & RV8803_FLAG_V1F)
461 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
462
463 if (flags & RV8803_FLAG_V2F)
464 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
465
466 if (flags & RV8803_FLAG_AF)
467 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
468
469 if (client->irq > 0) {
470 err = devm_request_threaded_irq(&client->dev, client->irq,
471 NULL, rv8803_handle_irq,
472 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
473 "rv8803", client);
474 if (err) {
475 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
476 client->irq = 0;
477 } else {
478 rv8803_rtc_ops.read_alarm = rv8803_get_alarm;
479 rv8803_rtc_ops.set_alarm = rv8803_set_alarm;
480 rv8803_rtc_ops.alarm_irq_enable = rv8803_alarm_irq_enable;
481 }
482 }
483
484 rv8803->rtc = devm_rtc_device_register(&client->dev, client->name,
485 &rv8803_rtc_ops, THIS_MODULE);
486 if (IS_ERR(rv8803->rtc)) {
487 dev_err(&client->dev, "unable to register the class device\n");
488 return PTR_ERR(rv8803->rtc);
489 }
490
491 try = 0;
492 do {
493 err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
494 RV8803_EXT_WADA);
495 try++;
496 } while ((err == -ENXIO) && (try < 3));
497 if (err)
498 return err;
499
500 err = device_create_bin_file(&client->dev, &rv8803_nvram_attr);
501 if (err)
502 return err;
503
504 rv8803->rtc->max_user_freq = 1;
505
506 return 0;
507}
508
509static int rv8803_remove(struct i2c_client *client)
510{
511 device_remove_bin_file(&client->dev, &rv8803_nvram_attr);
512
513 return 0;
514}
515
516static const struct i2c_device_id rv8803_id[] = {
517 { "rv8803", 0 },
518 { "rx8900", 0 },
519 { }
520};
521MODULE_DEVICE_TABLE(i2c, rv8803_id);
522
523static struct i2c_driver rv8803_driver = {
524 .driver = {
525 .name = "rtc-rv8803",
526 },
527 .probe = rv8803_probe,
528 .remove = rv8803_remove,
529 .id_table = rv8803_id,
530};
531module_i2c_driver(rv8803_driver);
532
533MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>");
534MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
535MODULE_LICENSE("GPL v2");