1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Avionic Design GmbH
7 #include <linux/bitfield.h>
9 #include <linux/module.h>
10 #include <linux/regmap.h>
11 #include <linux/rtc.h>
13 #include <linux/pm_wakeirq.h>
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)
20 #define PCF8523_REG_CONTROL2 0x01
21 #define PCF8523_CONTROL2_AF BIT(3)
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)
29 #define PCF8523_REG_SECONDS 0x03
30 #define PCF8523_SECONDS_OS BIT(7)
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
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)
45 #define PCF8523_REG_OFFSET 0x0e
46 #define PCF8523_OFFSET_MODE BIT(7)
48 #define PCF8523_TMR_CLKOUT_CTRL 0x0f
51 struct rtc_device *rtc;
52 struct regmap *regmap;
55 static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
60 of_property_read_u32(node, "quartz-load-femtofarads", &load);
64 dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
68 value = PCF8523_CONTROL1_CAP_SEL;
74 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
75 PCF8523_CONTROL1_CAP_SEL, value);
78 static irqreturn_t pcf8523_irq(int irq, void *dev_id)
80 struct pcf8523 *pcf8523 = dev_id;
84 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
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);
99 static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
101 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
106 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
111 if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
114 if (regs[0] & PCF8523_SECONDS_OS) {
116 * If the oscillator was stopped, try to clear the flag. Upon
117 * power-up the flag is always set, but if we cannot clear it
118 * the oscillator isn't running properly for some reason. The
119 * sensible thing therefore is to return an error, signalling
120 * that the clock cannot be assumed to be correct.
123 regs[0] &= ~PCF8523_SECONDS_OS;
125 err = regmap_write(pcf8523->regmap, PCF8523_REG_SECONDS,
130 err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS,
135 if (value & PCF8523_SECONDS_OS)
141 tm->tm_sec = bcd2bin(regs[3] & 0x7f);
142 tm->tm_min = bcd2bin(regs[4] & 0x7f);
143 tm->tm_hour = bcd2bin(regs[5] & 0x3f);
144 tm->tm_mday = bcd2bin(regs[6] & 0x3f);
145 tm->tm_wday = regs[7] & 0x7;
146 tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
147 tm->tm_year = bcd2bin(regs[9]) + 100;
152 static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
154 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
158 err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
159 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
163 /* This will purposely overwrite PCF8523_SECONDS_OS */
164 regs[0] = bin2bcd(tm->tm_sec);
165 regs[1] = bin2bcd(tm->tm_min);
166 regs[2] = bin2bcd(tm->tm_hour);
167 regs[3] = bin2bcd(tm->tm_mday);
168 regs[4] = tm->tm_wday;
169 regs[5] = bin2bcd(tm->tm_mon + 1);
170 regs[6] = bin2bcd(tm->tm_year - 100);
172 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
176 * If the time cannot be set, restart the RTC anyway. Note
177 * that errors are ignored if the RTC cannot be started so
178 * that we have a chance to propagate the original error.
180 regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
181 PCF8523_CONTROL1_STOP, 0);
185 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
186 PCF8523_CONTROL1_STOP, 0);
189 static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
191 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
196 err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
202 tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
203 tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
204 tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
205 tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
207 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
210 tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
212 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
215 tm->pending = !!(value & PCF8523_CONTROL2_AF);
220 static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
222 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
224 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
225 PCF8523_CONTROL1_AIE, enabled ?
226 PCF8523_CONTROL1_AIE : 0);
229 static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
231 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
235 err = pcf8523_irq_enable(dev, 0);
239 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
243 regs[0] = bin2bcd(tm->time.tm_min);
244 regs[1] = bin2bcd(tm->time.tm_hour);
245 regs[2] = bin2bcd(tm->time.tm_mday);
248 err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
254 return pcf8523_irq_enable(dev, tm->enabled);
259 static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
261 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
265 switch (param->param) {
266 case RTC_PARAM_BACKUP_SWITCH_MODE:
267 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
271 value = FIELD_GET(PCF8523_CONTROL3_PM, value);
276 param->uvalue = RTC_BSM_LEVEL;
280 param->uvalue = RTC_BSM_DIRECT;
282 case PCF8523_PM_STANDBY:
283 param->uvalue = RTC_BSM_STANDBY;
286 param->uvalue = RTC_BSM_DISABLED;
298 static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
300 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
303 switch (param->param) {
304 case RTC_PARAM_BACKUP_SWITCH_MODE:
305 switch (param->uvalue) {
306 case RTC_BSM_DISABLED:
315 case RTC_BSM_STANDBY:
316 mode = PCF8523_PM_STANDBY;
322 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
324 FIELD_PREP(PCF8523_CONTROL3_PM, mode));
335 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
338 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
339 unsigned int flags = 0;
345 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
349 if (value & PCF8523_CONTROL3_BLF)
350 flags |= RTC_VL_BACKUP_LOW;
352 ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
356 if (value & PCF8523_SECONDS_OS)
357 flags |= RTC_VL_DATA_INVALID;
359 return put_user(flags, (unsigned int __user *)arg);
366 static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
368 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
373 err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
377 /* sign extend the 7-bit offset value */
379 *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
384 static int pcf8523_rtc_set_offset(struct device *dev, long offset)
386 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
390 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
391 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
393 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
394 value = reg_m0 & 0x7f;
396 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
398 return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
401 static const struct rtc_class_ops pcf8523_rtc_ops = {
402 .read_time = pcf8523_rtc_read_time,
403 .set_time = pcf8523_rtc_set_time,
404 .read_alarm = pcf8523_rtc_read_alarm,
405 .set_alarm = pcf8523_rtc_set_alarm,
406 .alarm_irq_enable = pcf8523_irq_enable,
407 .ioctl = pcf8523_rtc_ioctl,
408 .read_offset = pcf8523_rtc_read_offset,
409 .set_offset = pcf8523_rtc_set_offset,
410 .param_get = pcf8523_param_get,
411 .param_set = pcf8523_param_set,
414 static const struct regmap_config regmap_config = {
417 .max_register = 0x13,
420 static int pcf8523_probe(struct i2c_client *client)
422 struct pcf8523 *pcf8523;
423 struct rtc_device *rtc;
424 bool wakeup_source = false;
428 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
431 pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
435 pcf8523->regmap = devm_regmap_init_i2c(client, ®map_config);
436 if (IS_ERR(pcf8523->regmap))
437 return PTR_ERR(pcf8523->regmap);
439 i2c_set_clientdata(client, pcf8523);
441 rtc = devm_rtc_allocate_device(&client->dev);
446 err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
448 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
451 err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
455 if (value & PCF8523_SECONDS_OS) {
456 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
460 if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
461 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
462 value & ~PCF8523_CONTROL3_PM);
468 rtc->ops = &pcf8523_rtc_ops;
469 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
470 rtc->range_max = RTC_TIMESTAMP_END_2099;
471 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
472 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
474 if (client->irq > 0) {
475 unsigned long irqflags = IRQF_TRIGGER_LOW;
477 if (dev_fwnode(&client->dev))
480 err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
484 err = devm_request_threaded_irq(&client->dev, client->irq,
486 IRQF_SHARED | IRQF_ONESHOT | irqflags,
487 dev_name(&rtc->dev), pcf8523);
491 dev_pm_set_wake_irq(&client->dev, client->irq);
494 wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
495 if (client->irq > 0 || wakeup_source)
496 device_init_wakeup(&client->dev, true);
498 return devm_rtc_register_device(rtc);
501 static const struct i2c_device_id pcf8523_id[] = {
505 MODULE_DEVICE_TABLE(i2c, pcf8523_id);
507 static const struct of_device_id pcf8523_of_match[] = {
508 { .compatible = "nxp,pcf8523" },
509 { .compatible = "microcrystal,rv8523" },
512 MODULE_DEVICE_TABLE(of, pcf8523_of_match);
514 static struct i2c_driver pcf8523_driver = {
516 .name = "rtc-pcf8523",
517 .of_match_table = pcf8523_of_match,
519 .probe = pcf8523_probe,
520 .id_table = pcf8523_id,
522 module_i2c_driver(pcf8523_driver);
524 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
525 MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
526 MODULE_LICENSE("GPL v2");