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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Avionic Design GmbH
4 */
5
6#include <linux/bcd.h>
7#include <linux/bitfield.h>
8#include <linux/i2c.h>
9#include <linux/module.h>
10#include <linux/regmap.h>
11#include <linux/rtc.h>
12#include <linux/of.h>
13#include <linux/pm_wakeirq.h>
14
15#define PCF8523_REG_CONTROL1 0x00
16#define PCF8523_CONTROL1_CAP_SEL BIT(7)
17#define PCF8523_CONTROL1_STOP BIT(5)
18#define PCF8523_CONTROL1_AIE BIT(1)
19
20#define PCF8523_REG_CONTROL2 0x01
21#define PCF8523_CONTROL2_AF BIT(3)
22
23#define PCF8523_REG_CONTROL3 0x02
24#define PCF8523_CONTROL3_PM GENMASK(7, 5)
25#define PCF8523_PM_STANDBY 0x7
26#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
27#define PCF8523_CONTROL3_BSF BIT(3)
28
29#define PCF8523_REG_SECONDS 0x03
30#define PCF8523_SECONDS_OS BIT(7)
31
32#define PCF8523_REG_MINUTES 0x04
33#define PCF8523_REG_HOURS 0x05
34#define PCF8523_REG_DAYS 0x06
35#define PCF8523_REG_WEEKDAYS 0x07
36#define PCF8523_REG_MONTHS 0x08
37#define PCF8523_REG_YEARS 0x09
38
39#define PCF8523_REG_MINUTE_ALARM 0x0a
40#define PCF8523_REG_HOUR_ALARM 0x0b
41#define PCF8523_REG_DAY_ALARM 0x0c
42#define PCF8523_REG_WEEKDAY_ALARM 0x0d
43#define ALARM_DIS BIT(7)
44
45#define PCF8523_REG_OFFSET 0x0e
46#define PCF8523_OFFSET_MODE BIT(7)
47
48#define PCF8523_TMR_CLKOUT_CTRL 0x0f
49
50struct pcf8523 {
51 struct rtc_device *rtc;
52 struct regmap *regmap;
53};
54
55static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
56{
57 u32 load, value = 0;
58
59 load = 12500;
60 of_property_read_u32(node, "quartz-load-femtofarads", &load);
61
62 switch (load) {
63 default:
64 dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
65 load);
66 fallthrough;
67 case 12500:
68 value = PCF8523_CONTROL1_CAP_SEL;
69 break;
70 case 7000:
71 break;
72 }
73
74 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
75 PCF8523_CONTROL1_CAP_SEL, value);
76}
77
78static irqreturn_t pcf8523_irq(int irq, void *dev_id)
79{
80 struct pcf8523 *pcf8523 = dev_id;
81 u32 value;
82 int err;
83
84 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
85 if (err < 0)
86 return IRQ_HANDLED;
87
88 if (value & PCF8523_CONTROL2_AF) {
89 value &= ~PCF8523_CONTROL2_AF;
90 regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
91 rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
92
93 return IRQ_HANDLED;
94 }
95
96 return IRQ_NONE;
97}
98
99static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
100{
101 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
102 u8 regs[10];
103 int err;
104
105 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
106 sizeof(regs));
107 if (err < 0)
108 return err;
109
110 if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
111 return -EINVAL;
112
113 tm->tm_sec = bcd2bin(regs[3] & 0x7f);
114 tm->tm_min = bcd2bin(regs[4] & 0x7f);
115 tm->tm_hour = bcd2bin(regs[5] & 0x3f);
116 tm->tm_mday = bcd2bin(regs[6] & 0x3f);
117 tm->tm_wday = regs[7] & 0x7;
118 tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
119 tm->tm_year = bcd2bin(regs[9]) + 100;
120
121 return 0;
122}
123
124static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
125{
126 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
127 u8 regs[7];
128 int err;
129
130 err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
131 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
132 if (err < 0)
133 return err;
134
135 /* This will purposely overwrite PCF8523_SECONDS_OS */
136 regs[0] = bin2bcd(tm->tm_sec);
137 regs[1] = bin2bcd(tm->tm_min);
138 regs[2] = bin2bcd(tm->tm_hour);
139 regs[3] = bin2bcd(tm->tm_mday);
140 regs[4] = tm->tm_wday;
141 regs[5] = bin2bcd(tm->tm_mon + 1);
142 regs[6] = bin2bcd(tm->tm_year - 100);
143
144 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
145 sizeof(regs));
146 if (err < 0) {
147 /*
148 * If the time cannot be set, restart the RTC anyway. Note
149 * that errors are ignored if the RTC cannot be started so
150 * that we have a chance to propagate the original error.
151 */
152 regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
153 PCF8523_CONTROL1_STOP, 0);
154 return err;
155 }
156
157 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
158 PCF8523_CONTROL1_STOP, 0);
159}
160
161static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
162{
163 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
164 u8 regs[4];
165 u32 value;
166 int err;
167
168 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
169 sizeof(regs));
170 if (err < 0)
171 return err;
172
173 tm->time.tm_sec = 0;
174 tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
175 tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
176 tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
177 tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
178
179 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
180 if (err < 0)
181 return err;
182 tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
183
184 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
185 if (err < 0)
186 return err;
187 tm->pending = !!(value & PCF8523_CONTROL2_AF);
188
189 return 0;
190}
191
192static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
193{
194 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
195
196 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
197 PCF8523_CONTROL1_AIE, enabled ?
198 PCF8523_CONTROL1_AIE : 0);
199}
200
201static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
202{
203 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
204 u8 regs[5];
205 int err;
206
207 err = pcf8523_irq_enable(dev, 0);
208 if (err)
209 return err;
210
211 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
212 if (err < 0)
213 return err;
214
215 regs[0] = bin2bcd(tm->time.tm_min);
216 regs[1] = bin2bcd(tm->time.tm_hour);
217 regs[2] = bin2bcd(tm->time.tm_mday);
218 regs[3] = ALARM_DIS;
219
220 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
221 sizeof(regs));
222 if (err < 0)
223 return err;
224
225 if (tm->enabled)
226 return pcf8523_irq_enable(dev, tm->enabled);
227
228 return 0;
229}
230
231static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
232{
233 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
234 int ret;
235 u32 value;
236
237 switch (param->param) {
238 case RTC_PARAM_BACKUP_SWITCH_MODE:
239 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
240 if (ret < 0)
241 return ret;
242
243 value = FIELD_GET(PCF8523_CONTROL3_PM, value);
244
245 switch (value) {
246 case 0x0:
247 case 0x4:
248 param->uvalue = RTC_BSM_LEVEL;
249 break;
250 case 0x1:
251 case 0x5:
252 param->uvalue = RTC_BSM_DIRECT;
253 break;
254 case PCF8523_PM_STANDBY:
255 param->uvalue = RTC_BSM_STANDBY;
256 break;
257 default:
258 param->uvalue = RTC_BSM_DISABLED;
259 }
260
261 break;
262
263 default:
264 return -EINVAL;
265 }
266
267 return 0;
268}
269
270static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
271{
272 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
273 u8 mode;
274
275 switch (param->param) {
276 case RTC_PARAM_BACKUP_SWITCH_MODE:
277 switch (param->uvalue) {
278 case RTC_BSM_DISABLED:
279 mode = 0x2;
280 break;
281 case RTC_BSM_DIRECT:
282 mode = 0x1;
283 break;
284 case RTC_BSM_LEVEL:
285 mode = 0x0;
286 break;
287 case RTC_BSM_STANDBY:
288 mode = PCF8523_PM_STANDBY;
289 break;
290 default:
291 return -EINVAL;
292 }
293
294 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
295 PCF8523_CONTROL3_PM,
296 FIELD_PREP(PCF8523_CONTROL3_PM, mode));
297
298 break;
299
300 default:
301 return -EINVAL;
302 }
303
304 return 0;
305}
306
307static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
308 unsigned long arg)
309{
310 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
311 unsigned int flags = 0;
312 u32 value;
313 int ret;
314
315 switch (cmd) {
316 case RTC_VL_READ:
317 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
318 if (ret < 0)
319 return ret;
320
321 if (value & PCF8523_CONTROL3_BLF)
322 flags |= RTC_VL_BACKUP_LOW;
323
324 ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
325 if (ret < 0)
326 return ret;
327
328 if (value & PCF8523_SECONDS_OS)
329 flags |= RTC_VL_DATA_INVALID;
330
331 return put_user(flags, (unsigned int __user *)arg);
332
333 default:
334 return -ENOIOCTLCMD;
335 }
336}
337
338static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
339{
340 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
341 int err;
342 u32 value;
343 s8 val;
344
345 err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
346 if (err < 0)
347 return err;
348
349 /* sign extend the 7-bit offset value */
350 val = value << 1;
351 *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
352
353 return 0;
354}
355
356static int pcf8523_rtc_set_offset(struct device *dev, long offset)
357{
358 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
359 long reg_m0, reg_m1;
360 u32 value;
361
362 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
363 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
364
365 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
366 value = reg_m0 & 0x7f;
367 else
368 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
369
370 return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
371}
372
373#ifdef CONFIG_PM_SLEEP
374static int pcf8523_suspend(struct device *dev)
375{
376 struct i2c_client *client = to_i2c_client(dev);
377
378 if (client->irq > 0 && device_may_wakeup(dev))
379 enable_irq_wake(client->irq);
380
381 return 0;
382}
383
384static int pcf8523_resume(struct device *dev)
385{
386 struct i2c_client *client = to_i2c_client(dev);
387
388 if (client->irq > 0 && device_may_wakeup(dev))
389 disable_irq_wake(client->irq);
390
391 return 0;
392}
393#endif
394
395static SIMPLE_DEV_PM_OPS(pcf8523_pm, pcf8523_suspend, pcf8523_resume);
396
397static const struct rtc_class_ops pcf8523_rtc_ops = {
398 .read_time = pcf8523_rtc_read_time,
399 .set_time = pcf8523_rtc_set_time,
400 .read_alarm = pcf8523_rtc_read_alarm,
401 .set_alarm = pcf8523_rtc_set_alarm,
402 .alarm_irq_enable = pcf8523_irq_enable,
403 .ioctl = pcf8523_rtc_ioctl,
404 .read_offset = pcf8523_rtc_read_offset,
405 .set_offset = pcf8523_rtc_set_offset,
406 .param_get = pcf8523_param_get,
407 .param_set = pcf8523_param_set,
408};
409
410static const struct regmap_config regmap_config = {
411 .reg_bits = 8,
412 .val_bits = 8,
413 .max_register = 0x13,
414};
415
416static int pcf8523_probe(struct i2c_client *client)
417{
418 struct pcf8523 *pcf8523;
419 struct rtc_device *rtc;
420 bool wakeup_source = false;
421 u32 value;
422 int err;
423
424 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
425 return -ENODEV;
426
427 pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
428 if (!pcf8523)
429 return -ENOMEM;
430
431 pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
432 if (IS_ERR(pcf8523->regmap))
433 return PTR_ERR(pcf8523->regmap);
434
435 i2c_set_clientdata(client, pcf8523);
436
437 rtc = devm_rtc_allocate_device(&client->dev);
438 if (IS_ERR(rtc))
439 return PTR_ERR(rtc);
440 pcf8523->rtc = rtc;
441
442 err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
443 if (err < 0)
444 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
445 err);
446
447 err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
448 if (err < 0)
449 return err;
450
451 if (value & PCF8523_SECONDS_OS) {
452 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
453 if (err < 0)
454 return err;
455
456 if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
457 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
458 value & ~PCF8523_CONTROL3_PM);
459 if (err < 0)
460 return err;
461 }
462 }
463
464 rtc->ops = &pcf8523_rtc_ops;
465 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
466 rtc->range_max = RTC_TIMESTAMP_END_2099;
467 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
468 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
469
470 if (client->irq > 0) {
471 unsigned long irqflags = IRQF_TRIGGER_LOW;
472
473 if (dev_fwnode(&client->dev))
474 irqflags = 0;
475
476 err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
477 if (err < 0)
478 return err;
479
480 err = devm_request_threaded_irq(&client->dev, client->irq,
481 NULL, pcf8523_irq,
482 IRQF_SHARED | IRQF_ONESHOT | irqflags,
483 dev_name(&rtc->dev), pcf8523);
484 if (err)
485 return err;
486
487 dev_pm_set_wake_irq(&client->dev, client->irq);
488 }
489
490 wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
491 if (client->irq > 0 || wakeup_source)
492 device_init_wakeup(&client->dev, true);
493
494 return devm_rtc_register_device(rtc);
495}
496
497static const struct i2c_device_id pcf8523_id[] = {
498 { .name = "pcf8523" },
499 { }
500};
501MODULE_DEVICE_TABLE(i2c, pcf8523_id);
502
503static const struct of_device_id pcf8523_of_match[] = {
504 { .compatible = "nxp,pcf8523" },
505 { .compatible = "microcrystal,rv8523" },
506 { }
507};
508MODULE_DEVICE_TABLE(of, pcf8523_of_match);
509
510static struct i2c_driver pcf8523_driver = {
511 .driver = {
512 .name = "rtc-pcf8523",
513 .of_match_table = pcf8523_of_match,
514 .pm = &pcf8523_pm,
515 },
516 .probe = pcf8523_probe,
517 .id_table = pcf8523_id,
518};
519module_i2c_driver(pcf8523_driver);
520
521MODULE_AUTHOR("Thierry Reding <[email protected]>");
522MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
523MODULE_LICENSE("GPL v2");