1 // SPDX-License-Identifier: GPL-2.0
3 * RTC driver for the Micro Crystal RV8803
5 * Copyright (C) 2015 Micro Crystal SA
6 * Alexandre Belloni <alexandre.belloni@bootlin.com>
10 #include <linux/bcd.h>
11 #include <linux/bitops.h>
12 #include <linux/log2.h>
13 #include <linux/i2c.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of_device.h>
18 #include <linux/rtc.h>
20 #define RV8803_I2C_TRY_COUNT 4
22 #define RV8803_SEC 0x00
23 #define RV8803_MIN 0x01
24 #define RV8803_HOUR 0x02
25 #define RV8803_WEEK 0x03
26 #define RV8803_DAY 0x04
27 #define RV8803_MONTH 0x05
28 #define RV8803_YEAR 0x06
29 #define RV8803_RAM 0x07
30 #define RV8803_ALARM_MIN 0x08
31 #define RV8803_ALARM_HOUR 0x09
32 #define RV8803_ALARM_WEEK_OR_DAY 0x0A
33 #define RV8803_EXT 0x0D
34 #define RV8803_FLAG 0x0E
35 #define RV8803_CTRL 0x0F
37 #define RV8803_EXT_WADA BIT(6)
39 #define RV8803_FLAG_V1F BIT(0)
40 #define RV8803_FLAG_V2F BIT(1)
41 #define RV8803_FLAG_AF BIT(3)
42 #define RV8803_FLAG_TF BIT(4)
43 #define RV8803_FLAG_UF BIT(5)
45 #define RV8803_CTRL_RESET BIT(0)
47 #define RV8803_CTRL_EIE BIT(2)
48 #define RV8803_CTRL_AIE BIT(3)
49 #define RV8803_CTRL_TIE BIT(4)
50 #define RV8803_CTRL_UIE BIT(5)
52 #define RX8900_BACKUP_CTRL 0x18
53 #define RX8900_FLAG_SWOFF BIT(2)
54 #define RX8900_FLAG_VDETOFF BIT(3)
63 struct i2c_client *client;
64 struct rtc_device *rtc;
65 struct mutex flags_lock;
67 enum rv8803_type type;
70 static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
72 int try = RV8803_I2C_TRY_COUNT;
76 * There is a 61µs window during which the RTC does not acknowledge I2C
77 * transfers. In that case, ensure that there are multiple attempts.
80 ret = i2c_smbus_read_byte_data(client, reg);
81 while ((ret == -ENXIO || ret == -EIO) && --try);
83 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
88 static int rv8803_read_regs(const struct i2c_client *client,
89 u8 reg, u8 count, u8 *values)
91 int try = RV8803_I2C_TRY_COUNT;
95 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
96 while ((ret == -ENXIO || ret == -EIO) && --try);
99 "Unable to read registers 0x%02x..0x%02x\n",
100 reg, reg + count - 1);
101 return ret < 0 ? ret : -EIO;
107 static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
109 int try = RV8803_I2C_TRY_COUNT;
113 ret = i2c_smbus_write_byte_data(client, reg, value);
114 while ((ret == -ENXIO || ret == -EIO) && --try);
116 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
121 static int rv8803_write_regs(const struct i2c_client *client,
122 u8 reg, u8 count, const u8 *values)
124 int try = RV8803_I2C_TRY_COUNT;
128 ret = i2c_smbus_write_i2c_block_data(client, reg, count,
130 while ((ret == -ENXIO || ret == -EIO) && --try);
132 dev_err(&client->dev,
133 "Unable to write registers 0x%02x..0x%02x\n",
134 reg, reg + count - 1);
139 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
141 struct i2c_client *client = dev_id;
142 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
143 unsigned long events = 0;
146 mutex_lock(&rv8803->flags_lock);
148 flags = rv8803_read_reg(client, RV8803_FLAG);
150 mutex_unlock(&rv8803->flags_lock);
154 if (flags & RV8803_FLAG_V1F)
155 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
157 if (flags & RV8803_FLAG_V2F)
158 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
160 if (flags & RV8803_FLAG_TF) {
161 flags &= ~RV8803_FLAG_TF;
162 rv8803->ctrl &= ~RV8803_CTRL_TIE;
166 if (flags & RV8803_FLAG_AF) {
167 flags &= ~RV8803_FLAG_AF;
168 rv8803->ctrl &= ~RV8803_CTRL_AIE;
172 if (flags & RV8803_FLAG_UF) {
173 flags &= ~RV8803_FLAG_UF;
174 rv8803->ctrl &= ~RV8803_CTRL_UIE;
179 rtc_update_irq(rv8803->rtc, 1, events);
180 rv8803_write_reg(client, RV8803_FLAG, flags);
181 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
184 mutex_unlock(&rv8803->flags_lock);
189 static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
191 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
197 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
201 if (flags & RV8803_FLAG_V2F) {
202 dev_warn(dev, "Voltage low, data is invalid.\n");
206 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
210 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
211 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
215 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
219 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
220 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
221 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
222 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
223 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
224 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
225 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
230 static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
232 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
234 int ctrl, flags, ret;
236 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
241 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
242 ctrl | RV8803_CTRL_RESET);
246 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
247 date[RV8803_MIN] = bin2bcd(tm->tm_min);
248 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
249 date[RV8803_WEEK] = 1 << (tm->tm_wday);
250 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
251 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
252 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
254 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
258 /* Restart the clock */
259 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
260 ctrl & ~RV8803_CTRL_RESET);
264 mutex_lock(&rv8803->flags_lock);
266 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
268 mutex_unlock(&rv8803->flags_lock);
272 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
273 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
275 mutex_unlock(&rv8803->flags_lock);
280 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
282 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
283 struct i2c_client *client = rv8803->client;
287 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
291 flags = rv8803_read_reg(client, RV8803_FLAG);
295 alrm->time.tm_sec = 0;
296 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
297 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
298 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
300 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
301 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
306 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
308 struct i2c_client *client = to_i2c_client(dev);
309 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
314 /* The alarm has no seconds, round up to nearest minute */
315 if (alrm->time.tm_sec) {
316 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
318 alarm_time += 60 - alrm->time.tm_sec;
319 rtc_time64_to_tm(alarm_time, &alrm->time);
322 mutex_lock(&rv8803->flags_lock);
324 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
326 mutex_unlock(&rv8803->flags_lock);
330 alarmvals[0] = bin2bcd(alrm->time.tm_min);
331 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
332 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
334 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
335 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
336 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
339 mutex_unlock(&rv8803->flags_lock);
344 ctrl[0] &= ~RV8803_FLAG_AF;
345 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[0]);
346 mutex_unlock(&rv8803->flags_lock);
350 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
355 if (rv8803->rtc->uie_rtctimer.enabled)
356 rv8803->ctrl |= RV8803_CTRL_UIE;
357 if (rv8803->rtc->aie_timer.enabled)
358 rv8803->ctrl |= RV8803_CTRL_AIE;
360 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
369 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
371 struct i2c_client *client = to_i2c_client(dev);
372 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
373 int ctrl, flags, err;
378 if (rv8803->rtc->uie_rtctimer.enabled)
379 ctrl |= RV8803_CTRL_UIE;
380 if (rv8803->rtc->aie_timer.enabled)
381 ctrl |= RV8803_CTRL_AIE;
383 if (!rv8803->rtc->uie_rtctimer.enabled)
384 ctrl &= ~RV8803_CTRL_UIE;
385 if (!rv8803->rtc->aie_timer.enabled)
386 ctrl &= ~RV8803_CTRL_AIE;
389 mutex_lock(&rv8803->flags_lock);
390 flags = rv8803_read_reg(client, RV8803_FLAG);
392 mutex_unlock(&rv8803->flags_lock);
395 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
396 err = rv8803_write_reg(client, RV8803_FLAG, flags);
397 mutex_unlock(&rv8803->flags_lock);
401 if (ctrl != rv8803->ctrl) {
403 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
411 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
413 struct i2c_client *client = to_i2c_client(dev);
414 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
420 flags = rv8803_read_reg(client, RV8803_FLAG);
424 if (flags & RV8803_FLAG_V1F) {
425 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
426 vl = RTC_VL_ACCURACY_LOW;
429 if (flags & RV8803_FLAG_V2F)
430 vl |= RTC_VL_DATA_INVALID;
432 return put_user(vl, (unsigned int __user *)arg);
435 mutex_lock(&rv8803->flags_lock);
436 flags = rv8803_read_reg(client, RV8803_FLAG);
438 mutex_unlock(&rv8803->flags_lock);
442 flags &= ~RV8803_FLAG_V1F;
443 ret = rv8803_write_reg(client, RV8803_FLAG, flags);
444 mutex_unlock(&rv8803->flags_lock);
455 static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
458 return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
461 static int rv8803_nvram_read(void *priv, unsigned int offset,
462 void *val, size_t bytes)
466 ret = rv8803_read_reg(priv, RV8803_RAM);
475 static const struct rtc_class_ops rv8803_rtc_ops = {
476 .read_time = rv8803_get_time,
477 .set_time = rv8803_set_time,
478 .ioctl = rv8803_ioctl,
479 .read_alarm = rv8803_get_alarm,
480 .set_alarm = rv8803_set_alarm,
481 .alarm_irq_enable = rv8803_alarm_irq_enable,
484 static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
486 struct i2c_client *client = rv8803->client;
487 struct device_node *node = client->dev.of_node;
494 if (rv8803->type != rx_8900)
497 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
501 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err;
503 if (of_property_read_bool(node, "epson,vdet-disable"))
504 flags |= RX8900_FLAG_VDETOFF;
506 if (of_property_read_bool(node, "trickle-diode-disable"))
507 flags |= RX8900_FLAG_SWOFF;
509 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
513 static int rv8803_probe(struct i2c_client *client,
514 const struct i2c_device_id *id)
516 struct i2c_adapter *adapter = client->adapter;
517 struct rv8803_data *rv8803;
519 struct nvmem_config nvmem_cfg = {
520 .name = "rv8803_nvram",
524 .reg_read = rv8803_nvram_read,
525 .reg_write = rv8803_nvram_write,
529 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
530 I2C_FUNC_SMBUS_I2C_BLOCK)) {
531 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
535 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
540 mutex_init(&rv8803->flags_lock);
541 rv8803->client = client;
542 if (client->dev.of_node)
543 rv8803->type = (enum rv8803_type)
544 of_device_get_match_data(&client->dev);
546 rv8803->type = id->driver_data;
547 i2c_set_clientdata(client, rv8803);
549 flags = rv8803_read_reg(client, RV8803_FLAG);
553 if (flags & RV8803_FLAG_V1F)
554 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
556 if (flags & RV8803_FLAG_V2F)
557 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
559 if (flags & RV8803_FLAG_AF)
560 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
562 rv8803->rtc = devm_rtc_allocate_device(&client->dev);
563 if (IS_ERR(rv8803->rtc))
564 return PTR_ERR(rv8803->rtc);
566 if (client->irq > 0) {
567 err = devm_request_threaded_irq(&client->dev, client->irq,
568 NULL, rv8803_handle_irq,
569 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
572 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
577 clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
579 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
583 err = rx8900_trickle_charger_init(rv8803);
585 dev_err(&client->dev, "failed to init charger\n");
589 rv8803->rtc->ops = &rv8803_rtc_ops;
590 rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
591 rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
592 err = devm_rtc_register_device(rv8803->rtc);
596 devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
598 rv8803->rtc->max_user_freq = 1;
603 static const struct i2c_device_id rv8803_id[] = {
604 { "rv8803", rv_8803 },
605 { "rv8804", rx_8804 },
606 { "rx8803", rv_8803 },
607 { "rx8900", rx_8900 },
610 MODULE_DEVICE_TABLE(i2c, rv8803_id);
612 static const __maybe_unused struct of_device_id rv8803_of_match[] = {
614 .compatible = "microcrystal,rv8803",
615 .data = (void *)rv_8803
618 .compatible = "epson,rx8803",
619 .data = (void *)rv_8803
622 .compatible = "epson,rx8804",
623 .data = (void *)rx_8804
626 .compatible = "epson,rx8900",
627 .data = (void *)rx_8900
631 MODULE_DEVICE_TABLE(of, rv8803_of_match);
633 static struct i2c_driver rv8803_driver = {
635 .name = "rtc-rv8803",
636 .of_match_table = of_match_ptr(rv8803_of_match),
638 .probe = rv8803_probe,
639 .id_table = rv8803_id,
641 module_i2c_driver(rv8803_driver);
643 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
644 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
645 MODULE_LICENSE("GPL v2");