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6#include <linux/bcd.h>
7#include <linux/i2c.h>
8#include <linux/module.h>
9#include <linux/rtc.h>
10#include <linux/of.h>
11#include <linux/pm_wakeirq.h>
12
13#define PCF8523_REG_CONTROL1 0x00
14#define PCF8523_CONTROL1_CAP_SEL BIT(7)
15#define PCF8523_CONTROL1_STOP BIT(5)
16#define PCF8523_CONTROL1_AIE BIT(1)
17
18#define PCF8523_REG_CONTROL2 0x01
19#define PCF8523_CONTROL2_AF BIT(3)
20
21#define PCF8523_REG_CONTROL3 0x02
22#define PCF8523_CONTROL3_PM_BLD BIT(7)
23#define PCF8523_CONTROL3_PM_VDD BIT(6)
24#define PCF8523_CONTROL3_PM_DSM BIT(5)
25#define PCF8523_CONTROL3_PM_MASK 0xe0
26#define PCF8523_CONTROL3_BLF BIT(2)
27
28#define PCF8523_REG_SECONDS 0x03
29#define PCF8523_SECONDS_OS BIT(7)
30
31#define PCF8523_REG_MINUTES 0x04
32#define PCF8523_REG_HOURS 0x05
33#define PCF8523_REG_DAYS 0x06
34#define PCF8523_REG_WEEKDAYS 0x07
35#define PCF8523_REG_MONTHS 0x08
36#define PCF8523_REG_YEARS 0x09
37
38#define PCF8523_REG_MINUTE_ALARM 0x0a
39#define PCF8523_REG_HOUR_ALARM 0x0b
40#define PCF8523_REG_DAY_ALARM 0x0c
41#define PCF8523_REG_WEEKDAY_ALARM 0x0d
42#define ALARM_DIS BIT(7)
43
44#define PCF8523_REG_OFFSET 0x0e
45#define PCF8523_OFFSET_MODE BIT(7)
46
47#define PCF8523_TMR_CLKOUT_CTRL 0x0f
48
49struct pcf8523 {
50 struct rtc_device *rtc;
51 struct i2c_client *client;
52};
53
54static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
55{
56 struct i2c_msg msgs[2];
57 u8 value = 0;
58 int err;
59
60 msgs[0].addr = client->addr;
61 msgs[0].flags = 0;
62 msgs[0].len = sizeof(reg);
63 msgs[0].buf = ®
64
65 msgs[1].addr = client->addr;
66 msgs[1].flags = I2C_M_RD;
67 msgs[1].len = sizeof(value);
68 msgs[1].buf = &value;
69
70 err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
71 if (err < 0)
72 return err;
73
74 *valuep = value;
75
76 return 0;
77}
78
79static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
80{
81 u8 buffer[2] = { reg, value };
82 struct i2c_msg msg;
83 int err;
84
85 msg.addr = client->addr;
86 msg.flags = 0;
87 msg.len = sizeof(buffer);
88 msg.buf = buffer;
89
90 err = i2c_transfer(client->adapter, &msg, 1);
91 if (err < 0)
92 return err;
93
94 return 0;
95}
96
97static int pcf8523_voltage_low(struct i2c_client *client)
98{
99 u8 value;
100 int err;
101
102 err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);
103 if (err < 0)
104 return err;
105
106 return !!(value & PCF8523_CONTROL3_BLF);
107}
108
109static int pcf8523_load_capacitance(struct i2c_client *client)
110{
111 u32 load;
112 u8 value;
113 int err;
114
115 err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
116 if (err < 0)
117 return err;
118
119 load = 12500;
120 of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
121 &load);
122
123 switch (load) {
124 default:
125 dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
126 load);
127 fallthrough;
128 case 12500:
129 value |= PCF8523_CONTROL1_CAP_SEL;
130 break;
131 case 7000:
132 value &= ~PCF8523_CONTROL1_CAP_SEL;
133 break;
134 }
135
136 err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
137
138 return err;
139}
140
141static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
142{
143 u8 value;
144 int err;
145
146 err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);
147 if (err < 0)
148 return err;
149
150 value = (value & ~PCF8523_CONTROL3_PM_MASK) | pm;
151
152 err = pcf8523_write(client, PCF8523_REG_CONTROL3, value);
153 if (err < 0)
154 return err;
155
156 return 0;
157}
158
159static irqreturn_t pcf8523_irq(int irq, void *dev_id)
160{
161 struct pcf8523 *pcf8523 = i2c_get_clientdata(dev_id);
162 u8 value;
163 int err;
164
165 err = pcf8523_read(pcf8523->client, PCF8523_REG_CONTROL2, &value);
166 if (err < 0)
167 return IRQ_HANDLED;
168
169 if (value & PCF8523_CONTROL2_AF) {
170 value &= ~PCF8523_CONTROL2_AF;
171 pcf8523_write(pcf8523->client, PCF8523_REG_CONTROL2, value);
172 rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
173
174 return IRQ_HANDLED;
175 }
176
177 return IRQ_NONE;
178}
179
180static int pcf8523_stop_rtc(struct i2c_client *client)
181{
182 u8 value;
183 int err;
184
185 err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
186 if (err < 0)
187 return err;
188
189 value |= PCF8523_CONTROL1_STOP;
190
191 err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
192 if (err < 0)
193 return err;
194
195 return 0;
196}
197
198static int pcf8523_start_rtc(struct i2c_client *client)
199{
200 u8 value;
201 int err;
202
203 err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
204 if (err < 0)
205 return err;
206
207 value &= ~PCF8523_CONTROL1_STOP;
208
209 err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
210 if (err < 0)
211 return err;
212
213 return 0;
214}
215
216static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
217{
218 struct i2c_client *client = to_i2c_client(dev);
219 u8 start = PCF8523_REG_SECONDS, regs[7];
220 struct i2c_msg msgs[2];
221 int err;
222
223 err = pcf8523_voltage_low(client);
224 if (err < 0) {
225 return err;
226 } else if (err > 0) {
227 dev_err(dev, "low voltage detected, time is unreliable\n");
228 return -EINVAL;
229 }
230
231 msgs[0].addr = client->addr;
232 msgs[0].flags = 0;
233 msgs[0].len = 1;
234 msgs[0].buf = &start;
235
236 msgs[1].addr = client->addr;
237 msgs[1].flags = I2C_M_RD;
238 msgs[1].len = sizeof(regs);
239 msgs[1].buf = regs;
240
241 err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
242 if (err < 0)
243 return err;
244
245 if (regs[0] & PCF8523_SECONDS_OS)
246 return -EINVAL;
247
248 tm->tm_sec = bcd2bin(regs[0] & 0x7f);
249 tm->tm_min = bcd2bin(regs[1] & 0x7f);
250 tm->tm_hour = bcd2bin(regs[2] & 0x3f);
251 tm->tm_mday = bcd2bin(regs[3] & 0x3f);
252 tm->tm_wday = regs[4] & 0x7;
253 tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1;
254 tm->tm_year = bcd2bin(regs[6]) + 100;
255
256 return 0;
257}
258
259static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
260{
261 struct i2c_client *client = to_i2c_client(dev);
262 struct i2c_msg msg;
263 u8 regs[8];
264 int err;
265
266 err = pcf8523_stop_rtc(client);
267 if (err < 0)
268 return err;
269
270 regs[0] = PCF8523_REG_SECONDS;
271
272 regs[1] = bin2bcd(tm->tm_sec);
273 regs[2] = bin2bcd(tm->tm_min);
274 regs[3] = bin2bcd(tm->tm_hour);
275 regs[4] = bin2bcd(tm->tm_mday);
276 regs[5] = tm->tm_wday;
277 regs[6] = bin2bcd(tm->tm_mon + 1);
278 regs[7] = bin2bcd(tm->tm_year - 100);
279
280 msg.addr = client->addr;
281 msg.flags = 0;
282 msg.len = sizeof(regs);
283 msg.buf = regs;
284
285 err = i2c_transfer(client->adapter, &msg, 1);
286 if (err < 0) {
287
288
289
290
291
292 pcf8523_start_rtc(client);
293 return err;
294 }
295
296 return pcf8523_start_rtc(client);
297}
298
299static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
300{
301 struct i2c_client *client = to_i2c_client(dev);
302 u8 start = PCF8523_REG_MINUTE_ALARM, regs[4];
303 struct i2c_msg msgs[2];
304 u8 value;
305 int err;
306
307 msgs[0].addr = client->addr;
308 msgs[0].flags = 0;
309 msgs[0].len = 1;
310 msgs[0].buf = &start;
311
312 msgs[1].addr = client->addr;
313 msgs[1].flags = I2C_M_RD;
314 msgs[1].len = sizeof(regs);
315 msgs[1].buf = regs;
316
317 err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
318 if (err < 0)
319 return err;
320
321 tm->time.tm_sec = 0;
322 tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
323 tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
324 tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
325 tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
326
327 err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
328 if (err < 0)
329 return err;
330 tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
331
332 err = pcf8523_read(client, PCF8523_REG_CONTROL2, &value);
333 if (err < 0)
334 return err;
335 tm->pending = !!(value & PCF8523_CONTROL2_AF);
336
337 return 0;
338}
339
340static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
341{
342 struct i2c_client *client = to_i2c_client(dev);
343 u8 value;
344 int err;
345
346 err = pcf8523_read(client, PCF8523_REG_CONTROL1, &value);
347 if (err < 0)
348 return err;
349
350 value &= PCF8523_CONTROL1_AIE;
351
352 if (enabled)
353 value |= PCF8523_CONTROL1_AIE;
354
355 err = pcf8523_write(client, PCF8523_REG_CONTROL1, value);
356 if (err < 0)
357 return err;
358
359 return 0;
360}
361
362static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
363{
364 struct i2c_client *client = to_i2c_client(dev);
365 struct i2c_msg msg;
366 u8 regs[5];
367 int err;
368
369 err = pcf8523_irq_enable(dev, 0);
370 if (err)
371 return err;
372
373 err = pcf8523_write(client, PCF8523_REG_CONTROL2, 0);
374 if (err < 0)
375 return err;
376
377
378 if (tm->time.tm_sec) {
379 time64_t alarm_time = rtc_tm_to_time64(&tm->time);
380
381 alarm_time += 60 - tm->time.tm_sec;
382 rtc_time64_to_tm(alarm_time, &tm->time);
383 }
384
385 regs[0] = PCF8523_REG_MINUTE_ALARM;
386 regs[1] = bin2bcd(tm->time.tm_min);
387 regs[2] = bin2bcd(tm->time.tm_hour);
388 regs[3] = bin2bcd(tm->time.tm_mday);
389 regs[4] = ALARM_DIS;
390 msg.addr = client->addr;
391 msg.flags = 0;
392 msg.len = sizeof(regs);
393 msg.buf = regs;
394 err = i2c_transfer(client->adapter, &msg, 1);
395 if (err < 0)
396 return err;
397
398 if (tm->enabled)
399 return pcf8523_irq_enable(dev, tm->enabled);
400
401 return 0;
402}
403
404#ifdef CONFIG_RTC_INTF_DEV
405static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
406 unsigned long arg)
407{
408 struct i2c_client *client = to_i2c_client(dev);
409 unsigned int flags = 0;
410 u8 value;
411 int ret;
412
413 switch (cmd) {
414 case RTC_VL_READ:
415 ret = pcf8523_voltage_low(client);
416 if (ret < 0)
417 return ret;
418 if (ret)
419 flags |= RTC_VL_BACKUP_LOW;
420
421 ret = pcf8523_read(client, PCF8523_REG_SECONDS, &value);
422 if (ret < 0)
423 return ret;
424
425 if (value & PCF8523_SECONDS_OS)
426 flags |= RTC_VL_DATA_INVALID;
427
428 return put_user(flags, (unsigned int __user *)arg);
429
430 default:
431 return -ENOIOCTLCMD;
432 }
433}
434#else
435#define pcf8523_rtc_ioctl NULL
436#endif
437
438static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
439{
440 struct i2c_client *client = to_i2c_client(dev);
441 int err;
442 u8 value;
443 s8 val;
444
445 err = pcf8523_read(client, PCF8523_REG_OFFSET, &value);
446 if (err < 0)
447 return err;
448
449
450 val = value << 1;
451 *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
452
453 return 0;
454}
455
456static int pcf8523_rtc_set_offset(struct device *dev, long offset)
457{
458 struct i2c_client *client = to_i2c_client(dev);
459 long reg_m0, reg_m1;
460 u8 value;
461
462 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
463 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
464
465 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
466 value = reg_m0 & 0x7f;
467 else
468 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
469
470 return pcf8523_write(client, PCF8523_REG_OFFSET, value);
471}
472
473static const struct rtc_class_ops pcf8523_rtc_ops = {
474 .read_time = pcf8523_rtc_read_time,
475 .set_time = pcf8523_rtc_set_time,
476 .read_alarm = pcf8523_rtc_read_alarm,
477 .set_alarm = pcf8523_rtc_set_alarm,
478 .alarm_irq_enable = pcf8523_irq_enable,
479 .ioctl = pcf8523_rtc_ioctl,
480 .read_offset = pcf8523_rtc_read_offset,
481 .set_offset = pcf8523_rtc_set_offset,
482};
483
484static int pcf8523_probe(struct i2c_client *client,
485 const struct i2c_device_id *id)
486{
487 struct pcf8523 *pcf8523;
488 struct rtc_device *rtc;
489 bool wakeup_source = false;
490 int err;
491
492 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
493 return -ENODEV;
494
495 pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
496 if (!pcf8523)
497 return -ENOMEM;
498
499 i2c_set_clientdata(client, pcf8523);
500 pcf8523->client = client;
501
502 err = pcf8523_load_capacitance(client);
503 if (err < 0)
504 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
505 err);
506
507 err = pcf8523_set_pm(client, 0);
508 if (err < 0)
509 return err;
510
511 rtc = devm_rtc_allocate_device(&client->dev);
512 if (IS_ERR(rtc))
513 return PTR_ERR(rtc);
514
515 pcf8523->rtc = rtc;
516 rtc->ops = &pcf8523_rtc_ops;
517 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
518 rtc->range_max = RTC_TIMESTAMP_END_2099;
519 rtc->uie_unsupported = 1;
520
521 if (client->irq > 0) {
522 err = pcf8523_write(client, PCF8523_TMR_CLKOUT_CTRL, 0x38);
523 if (err < 0)
524 return err;
525
526 err = devm_request_threaded_irq(&client->dev, client->irq,
527 NULL, pcf8523_irq,
528 IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW,
529 dev_name(&rtc->dev), client);
530 if (err)
531 return err;
532
533 dev_pm_set_wake_irq(&client->dev, client->irq);
534 }
535
536#ifdef CONFIG_OF
537 wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
538#endif
539 if (client->irq > 0 || wakeup_source)
540 device_init_wakeup(&client->dev, true);
541
542 return devm_rtc_register_device(rtc);
543}
544
545static const struct i2c_device_id pcf8523_id[] = {
546 { "pcf8523", 0 },
547 { }
548};
549MODULE_DEVICE_TABLE(i2c, pcf8523_id);
550
551#ifdef CONFIG_OF
552static const struct of_device_id pcf8523_of_match[] = {
553 { .compatible = "nxp,pcf8523" },
554 { .compatible = "microcrystal,rv8523" },
555 { }
556};
557MODULE_DEVICE_TABLE(of, pcf8523_of_match);
558#endif
559
560static struct i2c_driver pcf8523_driver = {
561 .driver = {
562 .name = "rtc-pcf8523",
563 .of_match_table = of_match_ptr(pcf8523_of_match),
564 },
565 .probe = pcf8523_probe,
566 .id_table = pcf8523_id,
567};
568module_i2c_driver(pcf8523_driver);
569
570MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
571MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
572MODULE_LICENSE("GPL v2");
573
