Merge tag 'rtc-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
[sfrench/cifs-2.6.git] / drivers / rtc / rtc-rx8025.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Epson's RTC module RX-8025 SA/NB
4  *
5  * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
6  *
7  * Copyright (C) 2005 by Digi International Inc.
8  * All rights reserved.
9  *
10  * Modified by fengjh at rising.com.cn
11  * <lm-sensors@lm-sensors.org>
12  * 2006.11
13  *
14  * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
15  * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
16  * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
17  */
18 #include <linux/bcd.h>
19 #include <linux/bitops.h>
20 #include <linux/i2c.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/rtc.h>
24
25 /* Register definitions */
26 #define RX8025_REG_SEC          0x00
27 #define RX8025_REG_MIN          0x01
28 #define RX8025_REG_HOUR         0x02
29 #define RX8025_REG_WDAY         0x03
30 #define RX8025_REG_MDAY         0x04
31 #define RX8025_REG_MONTH        0x05
32 #define RX8025_REG_YEAR         0x06
33 #define RX8025_REG_DIGOFF       0x07
34 #define RX8025_REG_ALWMIN       0x08
35 #define RX8025_REG_ALWHOUR      0x09
36 #define RX8025_REG_ALWWDAY      0x0a
37 #define RX8025_REG_ALDMIN       0x0b
38 #define RX8025_REG_ALDHOUR      0x0c
39 /* 0x0d is reserved */
40 #define RX8025_REG_CTRL1        0x0e
41 #define RX8025_REG_CTRL2        0x0f
42
43 #define RX8025_BIT_CTRL1_CT     (7 << 0)
44 /* 1 Hz periodic level irq */
45 #define RX8025_BIT_CTRL1_CT_1HZ 4
46 #define RX8025_BIT_CTRL1_TEST   BIT(3)
47 #define RX8025_BIT_CTRL1_1224   BIT(5)
48 #define RX8025_BIT_CTRL1_DALE   BIT(6)
49 #define RX8025_BIT_CTRL1_WALE   BIT(7)
50
51 #define RX8025_BIT_CTRL2_DAFG   BIT(0)
52 #define RX8025_BIT_CTRL2_WAFG   BIT(1)
53 #define RX8025_BIT_CTRL2_CTFG   BIT(2)
54 #define RX8025_BIT_CTRL2_PON    BIT(4)
55 #define RX8025_BIT_CTRL2_XST    BIT(5)
56 #define RX8025_BIT_CTRL2_VDET   BIT(6)
57
58 /* Clock precision adjustment */
59 #define RX8025_ADJ_RESOLUTION   3050 /* in ppb */
60 #define RX8025_ADJ_DATA_MAX     62
61 #define RX8025_ADJ_DATA_MIN     -62
62
63 static const struct i2c_device_id rx8025_id[] = {
64         { "rx8025", 0 },
65         { }
66 };
67 MODULE_DEVICE_TABLE(i2c, rx8025_id);
68
69 struct rx8025_data {
70         struct i2c_client *client;
71         struct rtc_device *rtc;
72         u8 ctrl1;
73 };
74
75 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
76 {
77         return i2c_smbus_read_byte_data(client, number << 4);
78 }
79
80 static int rx8025_read_regs(const struct i2c_client *client,
81                             u8 number, u8 length, u8 *values)
82 {
83         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
84                                                 values);
85         if (ret != length)
86                 return ret < 0 ? ret : -EIO;
87
88         return 0;
89 }
90
91 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
92                             u8 value)
93 {
94         return i2c_smbus_write_byte_data(client, number << 4, value);
95 }
96
97 static s32 rx8025_write_regs(const struct i2c_client *client,
98                              u8 number, u8 length, const u8 *values)
99 {
100         return i2c_smbus_write_i2c_block_data(client, number << 4,
101                                               length, values);
102 }
103
104 static int rx8025_check_validity(struct device *dev)
105 {
106         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
107         int ctrl2;
108
109         ctrl2 = rx8025_read_reg(rx8025->client, RX8025_REG_CTRL2);
110         if (ctrl2 < 0)
111                 return ctrl2;
112
113         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
114                 dev_warn(dev, "power voltage drop detected\n");
115
116         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
117                 dev_warn(dev, "power-on reset detected, date is invalid\n");
118                 return -EINVAL;
119         }
120
121         if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
122                 dev_warn(dev, "crystal stopped, date is invalid\n");
123                 return -EINVAL;
124         }
125
126         return 0;
127 }
128
129 static int rx8025_reset_validity(struct i2c_client *client)
130 {
131         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
132
133         if (ctrl2 < 0)
134                 return ctrl2;
135
136         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
137
138         return rx8025_write_reg(client, RX8025_REG_CTRL2,
139                                 ctrl2 | RX8025_BIT_CTRL2_XST);
140 }
141
142 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
143 {
144         struct i2c_client *client = dev_id;
145         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
146         struct mutex *lock = &rx8025->rtc->ops_lock;
147         int status;
148
149         mutex_lock(lock);
150         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
151         if (status < 0)
152                 goto out;
153
154         if (!(status & RX8025_BIT_CTRL2_XST))
155                 dev_warn(&client->dev, "Oscillation stop was detected,"
156                          "you may have to readjust the clock\n");
157
158         if (status & RX8025_BIT_CTRL2_CTFG) {
159                 /* periodic */
160                 status &= ~RX8025_BIT_CTRL2_CTFG;
161                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
162         }
163
164         if (status & RX8025_BIT_CTRL2_DAFG) {
165                 /* alarm */
166                 status &= RX8025_BIT_CTRL2_DAFG;
167                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
168                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
169                         goto out;
170                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
171         }
172
173 out:
174         mutex_unlock(lock);
175
176         return IRQ_HANDLED;
177 }
178
179 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
180 {
181         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
182         u8 date[7];
183         int err;
184
185         err = rx8025_check_validity(dev);
186         if (err)
187                 return err;
188
189         err = rx8025_read_regs(rx8025->client, RX8025_REG_SEC, 7, date);
190         if (err)
191                 return err;
192
193         dev_dbg(dev, "%s: read %7ph\n", __func__, date);
194
195         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
196         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
197         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
198                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
199         else
200                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
201                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
202
203         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
204         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
205         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
206
207         dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
208
209         return 0;
210 }
211
212 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
213 {
214         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
215         u8 date[7];
216         int ret;
217
218         if ((dt->tm_year < 100) || (dt->tm_year > 199))
219                 return -EINVAL;
220
221         /*
222          * Here the read-only bits are written as "0".  I'm not sure if that
223          * is sound.
224          */
225         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
226         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
227         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
228                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
229         else
230                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
231                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
232
233         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
234         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
235         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
236         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
237
238         dev_dbg(dev, "%s: write %7ph\n", __func__, date);
239
240         ret = rx8025_write_regs(rx8025->client, RX8025_REG_SEC, 7, date);
241         if (ret < 0)
242                 return ret;
243
244         return rx8025_reset_validity(rx8025->client);
245 }
246
247 static int rx8025_init_client(struct i2c_client *client)
248 {
249         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
250         u8 ctrl[2], ctrl2;
251         int need_clear = 0;
252         int err;
253
254         err = rx8025_read_regs(rx8025->client, RX8025_REG_CTRL1, 2, ctrl);
255         if (err)
256                 goto out;
257
258         /* Keep test bit zero ! */
259         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
260
261         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
262                 dev_warn(&client->dev, "Alarm was detected\n");
263                 need_clear = 1;
264         }
265
266         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
267                 need_clear = 1;
268
269         if (need_clear) {
270                 ctrl2 = ctrl[1];
271                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
272                            RX8025_BIT_CTRL2_DAFG);
273
274                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
275         }
276 out:
277         return err;
278 }
279
280 /* Alarm support */
281 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
282 {
283         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
284         struct i2c_client *client = rx8025->client;
285         u8 ald[2];
286         int ctrl2, err;
287
288         if (client->irq <= 0)
289                 return -EINVAL;
290
291         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
292         if (err)
293                 return err;
294
295         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
296         if (ctrl2 < 0)
297                 return ctrl2;
298
299         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
300                 __func__, ald[0], ald[1], ctrl2);
301
302         /* Hardware alarms precision is 1 minute! */
303         t->time.tm_sec = 0;
304         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
305         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
306                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
307         else
308                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
309                         + (ald[1] & 0x20 ? 12 : 0);
310
311         dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
312         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
313         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
314
315         return err;
316 }
317
318 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
319 {
320         struct i2c_client *client = to_i2c_client(dev);
321         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
322         u8 ald[2];
323         int err;
324
325         if (client->irq <= 0)
326                 return -EINVAL;
327
328         /*
329          * Hardware alarm precision is 1 minute!
330          * round up to nearest minute
331          */
332         if (t->time.tm_sec) {
333                 time64_t alarm_time = rtc_tm_to_time64(&t->time);
334
335                 alarm_time += 60 - t->time.tm_sec;
336                 rtc_time64_to_tm(alarm_time, &t->time);
337         }
338
339         ald[0] = bin2bcd(t->time.tm_min);
340         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
341                 ald[1] = bin2bcd(t->time.tm_hour);
342         else
343                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
344                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
345
346         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
347
348         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
349                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
350                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
351                                        rx8025->ctrl1);
352                 if (err)
353                         return err;
354         }
355         err = rx8025_write_regs(rx8025->client, RX8025_REG_ALDMIN, 2, ald);
356         if (err)
357                 return err;
358
359         if (t->enabled) {
360                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
361                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
362                                        rx8025->ctrl1);
363                 if (err)
364                         return err;
365         }
366
367         return 0;
368 }
369
370 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
371 {
372         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
373         u8 ctrl1;
374         int err;
375
376         ctrl1 = rx8025->ctrl1;
377         if (enabled)
378                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
379         else
380                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
381
382         if (ctrl1 != rx8025->ctrl1) {
383                 rx8025->ctrl1 = ctrl1;
384                 err = rx8025_write_reg(rx8025->client, RX8025_REG_CTRL1,
385                                        rx8025->ctrl1);
386                 if (err)
387                         return err;
388         }
389         return 0;
390 }
391
392 static const struct rtc_class_ops rx8025_rtc_ops = {
393         .read_time = rx8025_get_time,
394         .set_time = rx8025_set_time,
395         .read_alarm = rx8025_read_alarm,
396         .set_alarm = rx8025_set_alarm,
397         .alarm_irq_enable = rx8025_alarm_irq_enable,
398 };
399
400 /*
401  * Clock precision adjustment support
402  *
403  * According to the RX8025 SA/NB application manual the frequency and
404  * temperature characteristics can be approximated using the following
405  * equation:
406  *
407  *   df = a * (ut - t)**2
408  *
409  *   df: Frequency deviation in any temperature
410  *   a : Coefficient = (-35 +-5) * 10**-9
411  *   ut: Ultimate temperature in degree = +25 +-5 degree
412  *   t : Any temperature in degree
413  *
414  * Note that the clock adjustment in ppb must be entered (which is
415  * the negative value of the deviation).
416  */
417 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
418 {
419         struct i2c_client *client = to_i2c_client(dev);
420         int digoff;
421
422         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
423         if (digoff < 0)
424                 return digoff;
425
426         *adj = digoff >= 64 ? digoff - 128 : digoff;
427         if (*adj > 0)
428                 (*adj)--;
429         *adj *= -RX8025_ADJ_RESOLUTION;
430
431         return 0;
432 }
433
434 static int rx8025_set_clock_adjust(struct device *dev, int adj)
435 {
436         struct i2c_client *client = to_i2c_client(dev);
437         u8 digoff;
438         int err;
439
440         adj /= -RX8025_ADJ_RESOLUTION;
441         if (adj > RX8025_ADJ_DATA_MAX)
442                 adj = RX8025_ADJ_DATA_MAX;
443         else if (adj < RX8025_ADJ_DATA_MIN)
444                 adj = RX8025_ADJ_DATA_MIN;
445         else if (adj > 0)
446                 adj++;
447         else if (adj < 0)
448                 adj += 128;
449         digoff = adj;
450
451         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
452         if (err)
453                 return err;
454
455         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
456
457         return 0;
458 }
459
460 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
461                                               struct device_attribute *attr,
462                                               char *buf)
463 {
464         int err, adj;
465
466         err = rx8025_get_clock_adjust(dev, &adj);
467         if (err)
468                 return err;
469
470         return sprintf(buf, "%d\n", adj);
471 }
472
473 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
474                                                struct device_attribute *attr,
475                                                const char *buf, size_t count)
476 {
477         int adj, err;
478
479         if (sscanf(buf, "%i", &adj) != 1)
480                 return -EINVAL;
481
482         err = rx8025_set_clock_adjust(dev, adj);
483
484         return err ? err : count;
485 }
486
487 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
488                    rx8025_sysfs_show_clock_adjust,
489                    rx8025_sysfs_store_clock_adjust);
490
491 static int rx8025_sysfs_register(struct device *dev)
492 {
493         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
494 }
495
496 static void rx8025_sysfs_unregister(struct device *dev)
497 {
498         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
499 }
500
501 static int rx8025_probe(struct i2c_client *client,
502                         const struct i2c_device_id *id)
503 {
504         struct i2c_adapter *adapter = client->adapter;
505         struct rx8025_data *rx8025;
506         int err = 0;
507
508         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
509                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
510                 dev_err(&adapter->dev,
511                         "doesn't support required functionality\n");
512                 return -EIO;
513         }
514
515         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
516         if (!rx8025)
517                 return -ENOMEM;
518
519         rx8025->client = client;
520         i2c_set_clientdata(client, rx8025);
521
522         err = rx8025_init_client(client);
523         if (err)
524                 return err;
525
526         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
527                                           &rx8025_rtc_ops, THIS_MODULE);
528         if (IS_ERR(rx8025->rtc)) {
529                 dev_err(&client->dev, "unable to register the class device\n");
530                 return PTR_ERR(rx8025->rtc);
531         }
532
533         if (client->irq > 0) {
534                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
535                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
536                                                 rx8025_handle_irq,
537                                                 IRQF_ONESHOT,
538                                                 "rx8025", client);
539                 if (err) {
540                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
541                         client->irq = 0;
542                 }
543         }
544
545         rx8025->rtc->max_user_freq = 1;
546
547         /* the rx8025 alarm only supports a minute accuracy */
548         rx8025->rtc->uie_unsupported = 1;
549
550         err = rx8025_sysfs_register(&client->dev);
551         return err;
552 }
553
554 static int rx8025_remove(struct i2c_client *client)
555 {
556         rx8025_sysfs_unregister(&client->dev);
557         return 0;
558 }
559
560 static struct i2c_driver rx8025_driver = {
561         .driver = {
562                 .name = "rtc-rx8025",
563         },
564         .probe          = rx8025_probe,
565         .remove         = rx8025_remove,
566         .id_table       = rx8025_id,
567 };
568
569 module_i2c_driver(rx8025_driver);
570
571 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
572 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
573 MODULE_LICENSE("GPL");