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)
62 struct i2c_client *client;
63 struct rtc_device *rtc;
64 struct mutex flags_lock;
66 enum rv8803_type type;
69 static int rv8803_read_reg(const struct i2c_client *client, u8 reg)
71 int try = RV8803_I2C_TRY_COUNT;
75 * There is a 61µs window during which the RTC does not acknowledge I2C
76 * transfers. In that case, ensure that there are multiple attempts.
79 ret = i2c_smbus_read_byte_data(client, reg);
80 while ((ret == -ENXIO || ret == -EIO) && --try);
82 dev_err(&client->dev, "Unable to read register 0x%02x\n", reg);
87 static int rv8803_read_regs(const struct i2c_client *client,
88 u8 reg, u8 count, u8 *values)
90 int try = RV8803_I2C_TRY_COUNT;
94 ret = i2c_smbus_read_i2c_block_data(client, reg, count, values);
95 while ((ret == -ENXIO || ret == -EIO) && --try);
98 "Unable to read registers 0x%02x..0x%02x\n",
99 reg, reg + count - 1);
100 return ret < 0 ? ret : -EIO;
106 static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value)
108 int try = RV8803_I2C_TRY_COUNT;
112 ret = i2c_smbus_write_byte_data(client, reg, value);
113 while ((ret == -ENXIO || ret == -EIO) && --try);
115 dev_err(&client->dev, "Unable to write register 0x%02x\n", reg);
120 static int rv8803_write_regs(const struct i2c_client *client,
121 u8 reg, u8 count, const u8 *values)
123 int try = RV8803_I2C_TRY_COUNT;
127 ret = i2c_smbus_write_i2c_block_data(client, reg, count,
129 while ((ret == -ENXIO || ret == -EIO) && --try);
131 dev_err(&client->dev,
132 "Unable to write registers 0x%02x..0x%02x\n",
133 reg, reg + count - 1);
138 static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
140 struct i2c_client *client = dev_id;
141 struct rv8803_data *rv8803 = i2c_get_clientdata(client);
142 unsigned long events = 0;
145 mutex_lock(&rv8803->flags_lock);
147 flags = rv8803_read_reg(client, RV8803_FLAG);
149 mutex_unlock(&rv8803->flags_lock);
153 if (flags & RV8803_FLAG_V1F)
154 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
156 if (flags & RV8803_FLAG_V2F)
157 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
159 if (flags & RV8803_FLAG_TF) {
160 flags &= ~RV8803_FLAG_TF;
161 rv8803->ctrl &= ~RV8803_CTRL_TIE;
165 if (flags & RV8803_FLAG_AF) {
166 flags &= ~RV8803_FLAG_AF;
167 rv8803->ctrl &= ~RV8803_CTRL_AIE;
171 if (flags & RV8803_FLAG_UF) {
172 flags &= ~RV8803_FLAG_UF;
173 rv8803->ctrl &= ~RV8803_CTRL_UIE;
178 rtc_update_irq(rv8803->rtc, 1, events);
179 rv8803_write_reg(client, RV8803_FLAG, flags);
180 rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl);
183 mutex_unlock(&rv8803->flags_lock);
188 static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
190 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
196 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
200 if (flags & RV8803_FLAG_V2F) {
201 dev_warn(dev, "Voltage low, data is invalid.\n");
205 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date);
209 if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) {
210 ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2);
214 if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59))
218 tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f);
219 tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f);
220 tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f);
221 tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f);
222 tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f);
223 tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1;
224 tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100;
229 static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
231 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
233 int ctrl, flags, ret;
235 ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL);
240 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
241 ctrl | RV8803_CTRL_RESET);
245 date[RV8803_SEC] = bin2bcd(tm->tm_sec);
246 date[RV8803_MIN] = bin2bcd(tm->tm_min);
247 date[RV8803_HOUR] = bin2bcd(tm->tm_hour);
248 date[RV8803_WEEK] = 1 << (tm->tm_wday);
249 date[RV8803_DAY] = bin2bcd(tm->tm_mday);
250 date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1);
251 date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100);
253 ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date);
257 /* Restart the clock */
258 ret = rv8803_write_reg(rv8803->client, RV8803_CTRL,
259 ctrl & ~RV8803_CTRL_RESET);
263 mutex_lock(&rv8803->flags_lock);
265 flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
267 mutex_unlock(&rv8803->flags_lock);
271 ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
272 flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F));
274 mutex_unlock(&rv8803->flags_lock);
279 static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
281 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
282 struct i2c_client *client = rv8803->client;
286 ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals);
290 flags = rv8803_read_reg(client, RV8803_FLAG);
294 alrm->time.tm_sec = 0;
295 alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f);
296 alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);
297 alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);
299 alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
300 alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;
305 static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
307 struct i2c_client *client = to_i2c_client(dev);
308 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
313 /* The alarm has no seconds, round up to nearest minute */
314 if (alrm->time.tm_sec) {
315 time64_t alarm_time = rtc_tm_to_time64(&alrm->time);
317 alarm_time += 60 - alrm->time.tm_sec;
318 rtc_time64_to_tm(alarm_time, &alrm->time);
321 mutex_lock(&rv8803->flags_lock);
323 ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl);
325 mutex_unlock(&rv8803->flags_lock);
329 alarmvals[0] = bin2bcd(alrm->time.tm_min);
330 alarmvals[1] = bin2bcd(alrm->time.tm_hour);
331 alarmvals[2] = bin2bcd(alrm->time.tm_mday);
333 if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) {
334 rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE);
335 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
338 mutex_unlock(&rv8803->flags_lock);
343 ctrl[1] &= ~RV8803_FLAG_AF;
344 err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[1]);
345 mutex_unlock(&rv8803->flags_lock);
349 err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals);
354 if (rv8803->rtc->uie_rtctimer.enabled)
355 rv8803->ctrl |= RV8803_CTRL_UIE;
356 if (rv8803->rtc->aie_timer.enabled)
357 rv8803->ctrl |= RV8803_CTRL_AIE;
359 err = rv8803_write_reg(rv8803->client, RV8803_CTRL,
368 static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled)
370 struct i2c_client *client = to_i2c_client(dev);
371 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
372 int ctrl, flags, err;
377 if (rv8803->rtc->uie_rtctimer.enabled)
378 ctrl |= RV8803_CTRL_UIE;
379 if (rv8803->rtc->aie_timer.enabled)
380 ctrl |= RV8803_CTRL_AIE;
382 if (!rv8803->rtc->uie_rtctimer.enabled)
383 ctrl &= ~RV8803_CTRL_UIE;
384 if (!rv8803->rtc->aie_timer.enabled)
385 ctrl &= ~RV8803_CTRL_AIE;
388 mutex_lock(&rv8803->flags_lock);
389 flags = rv8803_read_reg(client, RV8803_FLAG);
391 mutex_unlock(&rv8803->flags_lock);
394 flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
395 err = rv8803_write_reg(client, RV8803_FLAG, flags);
396 mutex_unlock(&rv8803->flags_lock);
400 if (ctrl != rv8803->ctrl) {
402 err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl);
410 static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
412 struct i2c_client *client = to_i2c_client(dev);
413 struct rv8803_data *rv8803 = dev_get_drvdata(dev);
419 flags = rv8803_read_reg(client, RV8803_FLAG);
423 if (flags & RV8803_FLAG_V1F) {
424 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
425 vl = RTC_VL_ACCURACY_LOW;
428 if (flags & RV8803_FLAG_V2F)
429 vl |= RTC_VL_DATA_INVALID;
431 return put_user(vl, (unsigned int __user *)arg);
434 mutex_lock(&rv8803->flags_lock);
435 flags = rv8803_read_reg(client, RV8803_FLAG);
437 mutex_unlock(&rv8803->flags_lock);
441 flags &= ~RV8803_FLAG_V1F;
442 ret = rv8803_write_reg(client, RV8803_FLAG, flags);
443 mutex_unlock(&rv8803->flags_lock);
454 static int rv8803_nvram_write(void *priv, unsigned int offset, void *val,
457 return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val);
460 static int rv8803_nvram_read(void *priv, unsigned int offset,
461 void *val, size_t bytes)
465 ret = rv8803_read_reg(priv, RV8803_RAM);
474 static const struct rtc_class_ops rv8803_rtc_ops = {
475 .read_time = rv8803_get_time,
476 .set_time = rv8803_set_time,
477 .ioctl = rv8803_ioctl,
478 .read_alarm = rv8803_get_alarm,
479 .set_alarm = rv8803_set_alarm,
480 .alarm_irq_enable = rv8803_alarm_irq_enable,
483 static int rx8900_trickle_charger_init(struct rv8803_data *rv8803)
485 struct i2c_client *client = rv8803->client;
486 struct device_node *node = client->dev.of_node;
493 if (rv8803->type != rx_8900)
496 err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL);
500 flags = ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF) & (u8)err;
502 if (of_property_read_bool(node, "epson,vdet-disable"))
503 flags |= RX8900_FLAG_VDETOFF;
505 if (of_property_read_bool(node, "trickle-diode-disable"))
506 flags |= RX8900_FLAG_SWOFF;
508 return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL,
512 static int rv8803_probe(struct i2c_client *client,
513 const struct i2c_device_id *id)
515 struct i2c_adapter *adapter = client->adapter;
516 struct rv8803_data *rv8803;
518 struct nvmem_config nvmem_cfg = {
519 .name = "rv8803_nvram",
523 .reg_read = rv8803_nvram_read,
524 .reg_write = rv8803_nvram_write,
528 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
529 I2C_FUNC_SMBUS_I2C_BLOCK)) {
530 dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
534 rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data),
539 mutex_init(&rv8803->flags_lock);
540 rv8803->client = client;
541 if (client->dev.of_node)
542 rv8803->type = (enum rv8803_type)
543 of_device_get_match_data(&client->dev);
545 rv8803->type = id->driver_data;
546 i2c_set_clientdata(client, rv8803);
548 flags = rv8803_read_reg(client, RV8803_FLAG);
552 if (flags & RV8803_FLAG_V1F)
553 dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
555 if (flags & RV8803_FLAG_V2F)
556 dev_warn(&client->dev, "Voltage low, data loss detected.\n");
558 if (flags & RV8803_FLAG_AF)
559 dev_warn(&client->dev, "An alarm maybe have been missed.\n");
561 rv8803->rtc = devm_rtc_allocate_device(&client->dev);
562 if (IS_ERR(rv8803->rtc))
563 return PTR_ERR(rv8803->rtc);
565 if (client->irq > 0) {
566 err = devm_request_threaded_irq(&client->dev, client->irq,
567 NULL, rv8803_handle_irq,
568 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
571 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
576 clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features);
578 err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA);
582 err = rx8900_trickle_charger_init(rv8803);
584 dev_err(&client->dev, "failed to init charger\n");
588 rv8803->rtc->ops = &rv8803_rtc_ops;
589 rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
590 rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099;
591 err = devm_rtc_register_device(rv8803->rtc);
595 devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg);
597 rv8803->rtc->max_user_freq = 1;
602 static const struct i2c_device_id rv8803_id[] = {
603 { "rv8803", rv_8803 },
604 { "rx8803", rv_8803 },
605 { "rx8900", rx_8900 },
608 MODULE_DEVICE_TABLE(i2c, rv8803_id);
610 static const __maybe_unused struct of_device_id rv8803_of_match[] = {
612 .compatible = "microcrystal,rv8803",
613 .data = (void *)rv_8803
616 .compatible = "epson,rx8803",
617 .data = (void *)rv_8803
620 .compatible = "epson,rx8900",
621 .data = (void *)rx_8900
625 MODULE_DEVICE_TABLE(of, rv8803_of_match);
627 static struct i2c_driver rv8803_driver = {
629 .name = "rtc-rv8803",
630 .of_match_table = of_match_ptr(rv8803_of_match),
632 .probe = rv8803_probe,
633 .id_table = rv8803_id,
635 module_i2c_driver(rv8803_driver);
637 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
638 MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver");
639 MODULE_LICENSE("GPL v2");