1 // SPDX-License-Identifier: GPL-2.0-only
3 * Driver for Epson's RTC module RX-8025 SA/NB
5 * Copyright (C) 2009 Wolfgang Grandegger <wg@grandegger.com>
7 * Copyright (C) 2005 by Digi International Inc.
10 * Modified by fengjh at rising.com.cn
11 * <lm-sensors@lm-sensors.org>
14 * Code cleanup by Sergei Poselenov, <sposelenov@emcraft.com>
15 * Converted to new style by Wolfgang Grandegger <wg@grandegger.com>
16 * Alarm and periodic interrupt added by Dmitry Rakhchev <rda@emcraft.com>
18 #include <linux/bcd.h>
19 #include <linux/bitops.h>
20 #include <linux/i2c.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/rtc.h>
25 /* Register definitions */
26 #define RX8025_REG_SEC 0x00
27 #define RX8025_REG_MIN 0x01
28 #define RX8025_REG_HOUR 0x02
29 #define RX8025_REG_WDAY 0x03
30 #define RX8025_REG_MDAY 0x04
31 #define RX8025_REG_MONTH 0x05
32 #define RX8025_REG_YEAR 0x06
33 #define RX8025_REG_DIGOFF 0x07
34 #define RX8025_REG_ALWMIN 0x08
35 #define RX8025_REG_ALWHOUR 0x09
36 #define RX8025_REG_ALWWDAY 0x0a
37 #define RX8025_REG_ALDMIN 0x0b
38 #define RX8025_REG_ALDHOUR 0x0c
39 /* 0x0d is reserved */
40 #define RX8025_REG_CTRL1 0x0e
41 #define RX8025_REG_CTRL2 0x0f
43 #define RX8025_BIT_CTRL1_CT (7 << 0)
44 /* 1 Hz periodic level irq */
45 #define RX8025_BIT_CTRL1_CT_1HZ 4
46 #define RX8025_BIT_CTRL1_TEST BIT(3)
47 #define RX8025_BIT_CTRL1_1224 BIT(5)
48 #define RX8025_BIT_CTRL1_DALE BIT(6)
49 #define RX8025_BIT_CTRL1_WALE BIT(7)
51 #define RX8025_BIT_CTRL2_DAFG BIT(0)
52 #define RX8025_BIT_CTRL2_WAFG BIT(1)
53 #define RX8025_BIT_CTRL2_CTFG BIT(2)
54 #define RX8025_BIT_CTRL2_PON BIT(4)
55 #define RX8025_BIT_CTRL2_XST BIT(5)
56 #define RX8025_BIT_CTRL2_VDET BIT(6)
58 /* Clock precision adjustment */
59 #define RX8025_ADJ_RESOLUTION 3050 /* in ppb */
60 #define RX8025_ADJ_DATA_MAX 62
61 #define RX8025_ADJ_DATA_MIN -62
63 static const struct i2c_device_id rx8025_id[] = {
67 MODULE_DEVICE_TABLE(i2c, rx8025_id);
70 struct rtc_device *rtc;
74 static s32 rx8025_read_reg(const struct i2c_client *client, u8 number)
76 return i2c_smbus_read_byte_data(client, number << 4);
79 static int rx8025_read_regs(const struct i2c_client *client,
80 u8 number, u8 length, u8 *values)
82 int ret = i2c_smbus_read_i2c_block_data(client, number << 4, length,
85 return ret < 0 ? ret : -EIO;
90 static s32 rx8025_write_reg(const struct i2c_client *client, u8 number,
93 return i2c_smbus_write_byte_data(client, number << 4, value);
96 static s32 rx8025_write_regs(const struct i2c_client *client,
97 u8 number, u8 length, const u8 *values)
99 return i2c_smbus_write_i2c_block_data(client, number << 4,
103 static int rx8025_check_validity(struct device *dev)
105 struct i2c_client *client = to_i2c_client(dev);
108 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
112 if (ctrl2 & RX8025_BIT_CTRL2_VDET)
113 dev_warn(dev, "power voltage drop detected\n");
115 if (ctrl2 & RX8025_BIT_CTRL2_PON) {
116 dev_warn(dev, "power-on reset detected, date is invalid\n");
120 if (!(ctrl2 & RX8025_BIT_CTRL2_XST)) {
121 dev_warn(dev, "crystal stopped, date is invalid\n");
128 static int rx8025_reset_validity(struct i2c_client *client)
130 int ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
135 ctrl2 &= ~(RX8025_BIT_CTRL2_PON | RX8025_BIT_CTRL2_VDET);
137 return rx8025_write_reg(client, RX8025_REG_CTRL2,
138 ctrl2 | RX8025_BIT_CTRL2_XST);
141 static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
143 struct i2c_client *client = dev_id;
144 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
147 rtc_lock(rx8025->rtc);
148 status = rx8025_read_reg(client, RX8025_REG_CTRL2);
152 if (!(status & RX8025_BIT_CTRL2_XST))
153 dev_warn(&client->dev, "Oscillation stop was detected,"
154 "you may have to readjust the clock\n");
156 if (status & RX8025_BIT_CTRL2_CTFG) {
158 status &= ~RX8025_BIT_CTRL2_CTFG;
159 rtc_update_irq(rx8025->rtc, 1, RTC_PF | RTC_IRQF);
162 if (status & RX8025_BIT_CTRL2_DAFG) {
164 status &= RX8025_BIT_CTRL2_DAFG;
165 if (rx8025_write_reg(client, RX8025_REG_CTRL1,
166 rx8025->ctrl1 & ~RX8025_BIT_CTRL1_DALE))
168 rtc_update_irq(rx8025->rtc, 1, RTC_AF | RTC_IRQF);
172 rtc_unlock(rx8025->rtc);
177 static int rx8025_get_time(struct device *dev, struct rtc_time *dt)
179 struct i2c_client *client = to_i2c_client(dev);
180 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
184 err = rx8025_check_validity(dev);
188 err = rx8025_read_regs(client, RX8025_REG_SEC, 7, date);
192 dev_dbg(dev, "%s: read %7ph\n", __func__, date);
194 dt->tm_sec = bcd2bin(date[RX8025_REG_SEC] & 0x7f);
195 dt->tm_min = bcd2bin(date[RX8025_REG_MIN] & 0x7f);
196 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
197 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x3f);
199 dt->tm_hour = bcd2bin(date[RX8025_REG_HOUR] & 0x1f) % 12
200 + (date[RX8025_REG_HOUR] & 0x20 ? 12 : 0);
202 dt->tm_mday = bcd2bin(date[RX8025_REG_MDAY] & 0x3f);
203 dt->tm_mon = bcd2bin(date[RX8025_REG_MONTH] & 0x1f) - 1;
204 dt->tm_year = bcd2bin(date[RX8025_REG_YEAR]) + 100;
206 dev_dbg(dev, "%s: date %ptRr\n", __func__, dt);
211 static int rx8025_set_time(struct device *dev, struct rtc_time *dt)
213 struct i2c_client *client = to_i2c_client(dev);
214 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
218 if ((dt->tm_year < 100) || (dt->tm_year > 199))
222 * Here the read-only bits are written as "0". I'm not sure if that
225 date[RX8025_REG_SEC] = bin2bcd(dt->tm_sec);
226 date[RX8025_REG_MIN] = bin2bcd(dt->tm_min);
227 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
228 date[RX8025_REG_HOUR] = bin2bcd(dt->tm_hour);
230 date[RX8025_REG_HOUR] = (dt->tm_hour >= 12 ? 0x20 : 0)
231 | bin2bcd((dt->tm_hour + 11) % 12 + 1);
233 date[RX8025_REG_WDAY] = bin2bcd(dt->tm_wday);
234 date[RX8025_REG_MDAY] = bin2bcd(dt->tm_mday);
235 date[RX8025_REG_MONTH] = bin2bcd(dt->tm_mon + 1);
236 date[RX8025_REG_YEAR] = bin2bcd(dt->tm_year - 100);
238 dev_dbg(dev, "%s: write %7ph\n", __func__, date);
240 ret = rx8025_write_regs(client, RX8025_REG_SEC, 7, date);
244 return rx8025_reset_validity(client);
247 static int rx8025_init_client(struct i2c_client *client)
249 struct rx8025_data *rx8025 = i2c_get_clientdata(client);
254 err = rx8025_read_regs(client, RX8025_REG_CTRL1, 2, ctrl);
258 /* Keep test bit zero ! */
259 rx8025->ctrl1 = ctrl[0] & ~RX8025_BIT_CTRL1_TEST;
261 if (ctrl[1] & (RX8025_BIT_CTRL2_DAFG | RX8025_BIT_CTRL2_WAFG)) {
262 dev_warn(&client->dev, "Alarm was detected\n");
266 if (ctrl[1] & RX8025_BIT_CTRL2_CTFG)
271 ctrl2 &= ~(RX8025_BIT_CTRL2_CTFG | RX8025_BIT_CTRL2_WAFG |
272 RX8025_BIT_CTRL2_DAFG);
274 err = rx8025_write_reg(client, RX8025_REG_CTRL2, ctrl2);
281 static int rx8025_read_alarm(struct device *dev, struct rtc_wkalrm *t)
283 struct i2c_client *client = to_i2c_client(dev);
284 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
288 if (client->irq <= 0)
291 err = rx8025_read_regs(client, RX8025_REG_ALDMIN, 2, ald);
295 ctrl2 = rx8025_read_reg(client, RX8025_REG_CTRL2);
299 dev_dbg(dev, "%s: read alarm 0x%02x 0x%02x ctrl2 %02x\n",
300 __func__, ald[0], ald[1], ctrl2);
302 /* Hardware alarms precision is 1 minute! */
304 t->time.tm_min = bcd2bin(ald[0] & 0x7f);
305 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
306 t->time.tm_hour = bcd2bin(ald[1] & 0x3f);
308 t->time.tm_hour = bcd2bin(ald[1] & 0x1f) % 12
309 + (ald[1] & 0x20 ? 12 : 0);
311 dev_dbg(dev, "%s: date: %ptRr\n", __func__, &t->time);
312 t->enabled = !!(rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE);
313 t->pending = (ctrl2 & RX8025_BIT_CTRL2_DAFG) && t->enabled;
318 static int rx8025_set_alarm(struct device *dev, struct rtc_wkalrm *t)
320 struct i2c_client *client = to_i2c_client(dev);
321 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
325 if (client->irq <= 0)
329 * Hardware alarm precision is 1 minute!
330 * round up to nearest minute
332 if (t->time.tm_sec) {
333 time64_t alarm_time = rtc_tm_to_time64(&t->time);
335 alarm_time += 60 - t->time.tm_sec;
336 rtc_time64_to_tm(alarm_time, &t->time);
339 ald[0] = bin2bcd(t->time.tm_min);
340 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_1224)
341 ald[1] = bin2bcd(t->time.tm_hour);
343 ald[1] = (t->time.tm_hour >= 12 ? 0x20 : 0)
344 | bin2bcd((t->time.tm_hour + 11) % 12 + 1);
346 dev_dbg(dev, "%s: write 0x%02x 0x%02x\n", __func__, ald[0], ald[1]);
348 if (rx8025->ctrl1 & RX8025_BIT_CTRL1_DALE) {
349 rx8025->ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
350 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
355 err = rx8025_write_regs(client, RX8025_REG_ALDMIN, 2, ald);
360 rx8025->ctrl1 |= RX8025_BIT_CTRL1_DALE;
361 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
370 static int rx8025_alarm_irq_enable(struct device *dev, unsigned int enabled)
372 struct i2c_client *client = to_i2c_client(dev);
373 struct rx8025_data *rx8025 = dev_get_drvdata(dev);
377 ctrl1 = rx8025->ctrl1;
379 ctrl1 |= RX8025_BIT_CTRL1_DALE;
381 ctrl1 &= ~RX8025_BIT_CTRL1_DALE;
383 if (ctrl1 != rx8025->ctrl1) {
384 rx8025->ctrl1 = ctrl1;
385 err = rx8025_write_reg(client, RX8025_REG_CTRL1,
393 static const struct rtc_class_ops rx8025_rtc_ops = {
394 .read_time = rx8025_get_time,
395 .set_time = rx8025_set_time,
396 .read_alarm = rx8025_read_alarm,
397 .set_alarm = rx8025_set_alarm,
398 .alarm_irq_enable = rx8025_alarm_irq_enable,
402 * Clock precision adjustment support
404 * According to the RX8025 SA/NB application manual the frequency and
405 * temperature characteristics can be approximated using the following
408 * df = a * (ut - t)**2
410 * df: Frequency deviation in any temperature
411 * a : Coefficient = (-35 +-5) * 10**-9
412 * ut: Ultimate temperature in degree = +25 +-5 degree
413 * t : Any temperature in degree
415 * Note that the clock adjustment in ppb must be entered (which is
416 * the negative value of the deviation).
418 static int rx8025_get_clock_adjust(struct device *dev, int *adj)
420 struct i2c_client *client = to_i2c_client(dev);
423 digoff = rx8025_read_reg(client, RX8025_REG_DIGOFF);
427 *adj = digoff >= 64 ? digoff - 128 : digoff;
430 *adj *= -RX8025_ADJ_RESOLUTION;
435 static int rx8025_set_clock_adjust(struct device *dev, int adj)
437 struct i2c_client *client = to_i2c_client(dev);
441 adj /= -RX8025_ADJ_RESOLUTION;
442 if (adj > RX8025_ADJ_DATA_MAX)
443 adj = RX8025_ADJ_DATA_MAX;
444 else if (adj < RX8025_ADJ_DATA_MIN)
445 adj = RX8025_ADJ_DATA_MIN;
452 err = rx8025_write_reg(client, RX8025_REG_DIGOFF, digoff);
456 dev_dbg(dev, "%s: write 0x%02x\n", __func__, digoff);
461 static ssize_t rx8025_sysfs_show_clock_adjust(struct device *dev,
462 struct device_attribute *attr,
467 err = rx8025_get_clock_adjust(dev, &adj);
471 return sprintf(buf, "%d\n", adj);
474 static ssize_t rx8025_sysfs_store_clock_adjust(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t count)
480 if (sscanf(buf, "%i", &adj) != 1)
483 err = rx8025_set_clock_adjust(dev, adj);
485 return err ? err : count;
488 static DEVICE_ATTR(clock_adjust_ppb, S_IRUGO | S_IWUSR,
489 rx8025_sysfs_show_clock_adjust,
490 rx8025_sysfs_store_clock_adjust);
492 static int rx8025_sysfs_register(struct device *dev)
494 return device_create_file(dev, &dev_attr_clock_adjust_ppb);
497 static void rx8025_sysfs_unregister(struct device *dev)
499 device_remove_file(dev, &dev_attr_clock_adjust_ppb);
502 static int rx8025_probe(struct i2c_client *client,
503 const struct i2c_device_id *id)
505 struct i2c_adapter *adapter = client->adapter;
506 struct rx8025_data *rx8025;
509 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
510 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
511 dev_err(&adapter->dev,
512 "doesn't support required functionality\n");
516 rx8025 = devm_kzalloc(&client->dev, sizeof(*rx8025), GFP_KERNEL);
520 i2c_set_clientdata(client, rx8025);
522 err = rx8025_init_client(client);
526 rx8025->rtc = devm_rtc_device_register(&client->dev, client->name,
527 &rx8025_rtc_ops, THIS_MODULE);
528 if (IS_ERR(rx8025->rtc)) {
529 dev_err(&client->dev, "unable to register the class device\n");
530 return PTR_ERR(rx8025->rtc);
533 if (client->irq > 0) {
534 dev_info(&client->dev, "IRQ %d supplied\n", client->irq);
535 err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
540 dev_err(&client->dev, "unable to request IRQ, alarms disabled\n");
545 rx8025->rtc->max_user_freq = 1;
547 /* the rx8025 alarm only supports a minute accuracy */
548 rx8025->rtc->uie_unsupported = 1;
550 err = rx8025_sysfs_register(&client->dev);
554 static int rx8025_remove(struct i2c_client *client)
556 rx8025_sysfs_unregister(&client->dev);
560 static struct i2c_driver rx8025_driver = {
562 .name = "rtc-rx8025",
564 .probe = rx8025_probe,
565 .remove = rx8025_remove,
566 .id_table = rx8025_id,
569 module_i2c_driver(rx8025_driver);
571 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
572 MODULE_DESCRIPTION("RX-8025 SA/NB RTC driver");
573 MODULE_LICENSE("GPL");