rtc: Add SPI alias for pcf2123 driver
[platform/kernel/linux-rpi.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 enum rx_model {
64         model_rx_unknown,
65         model_rx_8025,
66         model_rx_8035,
67         model_last
68 };
69
70 static const struct i2c_device_id rx8025_id[] = {
71         { "rx8025", model_rx_8025 },
72         { "rx8035", model_rx_8035 },
73         { }
74 };
75 MODULE_DEVICE_TABLE(i2c, rx8025_id);
76
77 struct rx8025_data {
78         struct rtc_device *rtc;
79         enum rx_model model;
80         u8 ctrl1;
81 };
82
83 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
84 {
85         return i2c_smbus_read_byte_data(client, number << 4);
86 }
87
88 static int rx8025_read_regs(const struct i2c_client *client,
89                             u8 number, u8 length, u8 *values)
90 {
91         int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
92                                                 values);
93         if (ret != length)
94                 return ret < 0 ? ret : -EIO;
95
96         return 0;
97 }
98
99 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
100                             u8 value)
101 {
102         return i2c_smbus_write_byte_data(client, number << 4, value);
103 }
104
105 static s32 rx8025_write_regs(const struct i2c_client *client,
106                              u8 number, u8 length, const u8 *values)
107 {
108         return i2c_smbus_write_i2c_block_data(client, number << 4,
109                                               length, values);
110 }
111
112 static int rx8025_is_osc_stopped(enum rx_model model, int ctrl2)
113 {
114         int xstp = ctrl2 & RX8025_BIT_CTRL2_XST;
115         /* XSTP bit has different polarity on RX-8025 vs RX-8035.
116          * RX-8025: 0 == oscillator stopped
117          * RX-8035: 1 == oscillator stopped
118          */
119
120         if (model == model_rx_8025)
121                 xstp = !xstp;
122
123         return xstp;
124 }
125
126 static int rx8025_check_validity(struct device *dev)
127 {
128         struct i2c_client *client = to_i2c_client(dev);
129         struct rx8025_data *drvdata = dev_get_drvdata(dev);
130         int ctrl2;
131         int xstp;
132
133         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
134         if (ctrl2 < 0)
135                 return ctrl2;
136
137         if (ctrl2 & RX8025_BIT_CTRL2_VDET)
138                 dev_warn(dev, "power voltage drop detected\n");
139
140         if (ctrl2 & RX8025_BIT_CTRL2_PON) {
141                 dev_warn(dev, "power-on reset detected, date is invalid\n");
142                 return -EINVAL;
143         }
144
145         xstp = rx8025_is_osc_stopped(drvdata->model, ctrl2);
146         if (xstp) {
147                 dev_warn(dev, "crystal stopped, date is invalid\n");
148                 return -EINVAL;
149         }
150
151         return 0;
152 }
153
154 static int rx8025_reset_validity(struct i2c_client *client)
155 {
156         struct rx8025_data *drvdata = i2c_get_clientdata(client);
157         int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
158
159         if (ctrl2 < 0)
160                 return ctrl2;
161
162         ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
163
164         if (drvdata->model == model_rx_8025)
165                 ctrl2 |= RX8025_BIT_CTRL2_XST;
166         else
167                 ctrl2 &= ~(RX8025_BIT_CTRL2_XST);
168
169         return rx8025_write_reg(client, RX8025_REG_CTRL2,
170                                 ctrl2);
171 }
172
173 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
174 {
175         struct i2c_client *client = dev_id;
176         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
177         int status, xstp;
178
179         rtc_lock(rx8025->rtc);
180         status = rx8025_read_reg(client, RX8025_REG_CTRL2);
181         if (status < 0)
182                 goto out;
183
184         xstp = rx8025_is_osc_stopped(rx8025->model, status);
185         if (xstp)
186                 dev_warn(&client->dev, "Oscillation stop was detected,"
187                          "you may have to readjust the clock\n");
188
189         if (status & RX8025_BIT_CTRL2_CTFG) {
190                 /* periodic */
191                 status &= ~RX8025_BIT_CTRL2_CTFG;
192                 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
193         }
194
195         if (status & RX8025_BIT_CTRL2_DAFG) {
196                 /* alarm */
197                 status &= RX8025_BIT_CTRL2_DAFG;
198                 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
199                                      rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
200                         goto out;
201                 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
202         }
203
204 out:
205         rtc_unlock(rx8025->rtc);
206
207         return IRQ_HANDLED;
208 }
209
210 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
211 {
212         struct i2c_client *client = to_i2c_client(dev);
213         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
214         u8 date[7];
215         int err;
216
217         err = rx8025_check_validity(dev);
218         if (err)
219                 return err;
220
221         err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
222         if (err)
223                 return err;
224
225         dev_dbg(dev, "%s: read %7ph\n", __func__, date);
226
227         dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
228         dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
229         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
230                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
231         else
232                 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
233                         + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
234
235         dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
236         dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
237         dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
238
239         dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
240
241         return 0;
242 }
243
244 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
245 {
246         struct i2c_client *client = to_i2c_client(dev);
247         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
248         u8 date[7];
249         int ret;
250
251         if ((dt->tm_year < 100) || (dt->tm_year > 199))
252                 return -EINVAL;
253
254         /*
255          * Here the read-only bits are written as "0".  I'm not sure if that
256          * is sound.
257          */
258         date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
259         date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
260         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
261                 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
262         else
263                 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
264                         | bin2bcd((dt->tm_hour + 11) % 12 + 1);
265
266         date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
267         date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
268         date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
269         date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
270
271         dev_dbg(dev, "%s: write %7ph\n", __func__, date);
272
273         ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
274         if (ret < 0)
275                 return ret;
276
277         return rx8025_reset_validity(client);
278 }
279
280 static int rx8025_init_client(struct i2c_client *client)
281 {
282         struct rx8025_data *rx8025 = i2c_get_clientdata(client);
283         u8 ctrl[2], ctrl2;
284         int need_clear = 0;
285         int err;
286
287         err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
288         if (err)
289                 goto out;
290
291         /* Keep test bit zero ! */
292         rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
293
294         if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
295                 dev_warn(&client->dev, "Alarm was detected\n");
296                 need_clear = 1;
297         }
298
299         if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
300                 need_clear = 1;
301
302         if (need_clear) {
303                 ctrl2 = ctrl[1];
304                 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
305                            RX8025_BIT_CTRL2_DAFG);
306
307                 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
308         }
309 out:
310         return err;
311 }
312
313 /* Alarm support */
314 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
315 {
316         struct i2c_client *client = to_i2c_client(dev);
317         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
318         u8 ald[2];
319         int ctrl2, err;
320
321         if (client->irq <= 0)
322                 return -EINVAL;
323
324         err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
325         if (err)
326                 return err;
327
328         ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
329         if (ctrl2 < 0)
330                 return ctrl2;
331
332         dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
333                 __func__, ald[0], ald[1], ctrl2);
334
335         /* Hardware alarms precision is 1 minute! */
336         t->time.tm_sec = 0;
337         t->time.tm_min = bcd2bin(ald[0] & 0x7f);
338         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
339                 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
340         else
341                 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
342                         + (ald[1] & 0x20 ? 12 : 0);
343
344         dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
345         t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
346         t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
347
348         return err;
349 }
350
351 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
352 {
353         struct i2c_client *client = to_i2c_client(dev);
354         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
355         u8 ald[2];
356         int err;
357
358         if (client->irq <= 0)
359                 return -EINVAL;
360
361         /*
362          * Hardware alarm precision is 1 minute!
363          * round up to nearest minute
364          */
365         if (t->time.tm_sec) {
366                 time64_t alarm_time = rtc_tm_to_time64(&t->time);
367
368                 alarm_time += 60 - t->time.tm_sec;
369                 rtc_time64_to_tm(alarm_time, &t->time);
370         }
371
372         ald[0] = bin2bcd(t->time.tm_min);
373         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
374                 ald[1] = bin2bcd(t->time.tm_hour);
375         else
376                 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
377                         | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
378
379         dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
380
381         if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
382                 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
383                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
384                                        rx8025->ctrl1);
385                 if (err)
386                         return err;
387         }
388         err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
389         if (err)
390                 return err;
391
392         if (t->enabled) {
393                 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
394                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
395                                        rx8025->ctrl1);
396                 if (err)
397                         return err;
398         }
399
400         return 0;
401 }
402
403 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
404 {
405         struct i2c_client *client = to_i2c_client(dev);
406         struct rx8025_data *rx8025 = dev_get_drvdata(dev);
407         u8 ctrl1;
408         int err;
409
410         ctrl1 = rx8025->ctrl1;
411         if (enabled)
412                 ctrl1 |= RX8025_BIT_CTRL1_DALE;
413         else
414                 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
415
416         if (ctrl1 != rx8025->ctrl1) {
417                 rx8025->ctrl1 = ctrl1;
418                 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
419                                        rx8025->ctrl1);
420                 if (err)
421                         return err;
422         }
423         return 0;
424 }
425
426 static const struct rtc_class_ops rx8025_rtc_ops = {
427         .read_time = rx8025_get_time,
428         .set_time = rx8025_set_time,
429         .read_alarm = rx8025_read_alarm,
430         .set_alarm = rx8025_set_alarm,
431         .alarm_irq_enable = rx8025_alarm_irq_enable,
432 };
433
434 /*
435  * Clock precision adjustment support
436  *
437  * According to the RX8025 SA/NB application manual the frequency and
438  * temperature characteristics can be approximated using the following
439  * equation:
440  *
441  *   df = a * (ut - t)**2
442  *
443  *   df: Frequency deviation in any temperature
444  *   a : Coefficient = (-35 +-5) * 10**-9
445  *   ut: Ultimate temperature in degree = +25 +-5 degree
446  *   t : Any temperature in degree
447  *
448  * Note that the clock adjustment in ppb must be entered (which is
449  * the negative value of the deviation).
450  */
451 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
452 {
453         struct i2c_client *client = to_i2c_client(dev);
454         int digoff;
455
456         digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
457         if (digoff < 0)
458                 return digoff;
459
460         *adj = digoff >= 64 ? digoff - 128 : digoff;
461         if (*adj > 0)
462                 (*adj)--;
463         *adj *= -RX8025_ADJ_RESOLUTION;
464
465         return 0;
466 }
467
468 static int rx8025_set_clock_adjust(struct device *dev, int adj)
469 {
470         struct i2c_client *client = to_i2c_client(dev);
471         u8 digoff;
472         int err;
473
474         adj /= -RX8025_ADJ_RESOLUTION;
475         if (adj > RX8025_ADJ_DATA_MAX)
476                 adj = RX8025_ADJ_DATA_MAX;
477         else if (adj < RX8025_ADJ_DATA_MIN)
478                 adj = RX8025_ADJ_DATA_MIN;
479         else if (adj > 0)
480                 adj++;
481         else if (adj < 0)
482                 adj += 128;
483         digoff = adj;
484
485         err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
486         if (err)
487                 return err;
488
489         dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
490
491         return 0;
492 }
493
494 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
495                                               struct device_attribute *attr,
496                                               char *buf)
497 {
498         int err, adj;
499
500         err = rx8025_get_clock_adjust(dev, &adj);
501         if (err)
502                 return err;
503
504         return sprintf(buf, "%d\n", adj);
505 }
506
507 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
508                                                struct device_attribute *attr,
509                                                const char *buf, size_t count)
510 {
511         int adj, err;
512
513         if (sscanf(buf, "%i", &adj) != 1)
514                 return -EINVAL;
515
516         err = rx8025_set_clock_adjust(dev, adj);
517
518         return err ? err : count;
519 }
520
521 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
522                    rx8025_sysfs_show_clock_adjust,
523                    rx8025_sysfs_store_clock_adjust);
524
525 static int rx8025_sysfs_register(struct device *dev)
526 {
527         return device_create_file(dev, &dev_attr_clock_adjust_ppb);
528 }
529
530 static void rx8025_sysfs_unregister(struct device *dev)
531 {
532         device_remove_file(dev, &dev_attr_clock_adjust_ppb);
533 }
534
535 static int rx8025_probe(struct i2c_client *client,
536                         const struct i2c_device_id *id)
537 {
538         struct i2c_adapter *adapter = client->adapter;
539         struct rx8025_data *rx8025;
540         int err = 0;
541
542         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
543                                      | I2C_FUNC_SMBUS_I2C_BLOCK)) {
544                 dev_err(&adapter->dev,
545                         "doesn't support required functionality\n");
546                 return -EIO;
547         }
548
549         rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
550         if (!rx8025)
551                 return -ENOMEM;
552
553         i2c_set_clientdata(client, rx8025);
554
555         if (id)
556                 rx8025->model = id->driver_data;
557
558         err = rx8025_init_client(client);
559         if (err)
560                 return err;
561
562         rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
563                                           &rx8025_rtc_ops, THIS_MODULE);
564         if (IS_ERR(rx8025->rtc)) {
565                 dev_err(&client->dev, "unable to register the class device\n");
566                 return PTR_ERR(rx8025->rtc);
567         }
568
569         if (client->irq > 0) {
570                 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
571                 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
572                                                 rx8025_handle_irq,
573                                                 IRQF_ONESHOT,
574                                                 "rx8025", client);
575                 if (err) {
576                         dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
577                         client->irq = 0;
578                 }
579         }
580
581         rx8025->rtc->max_user_freq = 1;
582
583         /* the rx8025 alarm only supports a minute accuracy */
584         rx8025->rtc->uie_unsupported = 1;
585
586         err = rx8025_sysfs_register(&client->dev);
587         return err;
588 }
589
590 static int rx8025_remove(struct i2c_client *client)
591 {
592         rx8025_sysfs_unregister(&client->dev);
593         return 0;
594 }
595
596 static struct i2c_driver rx8025_driver = {
597         .driver = {
598                 .name = "rtc-rx8025",
599         },
600         .probe          = rx8025_probe,
601         .remove         = rx8025_remove,
602         .id_table       = rx8025_id,
603 };
604
605 module_i2c_driver(rx8025_driver);
606
607 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
608 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
609 MODULE_LICENSE("GPL");