1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for the Epson RTC module RX-6110 SA
4 *
5 * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
6 * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved.
7 */
8
9 #include <linux/bcd.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/regmap.h>
14 #include <linux/rtc.h>
15 #include <linux/of.h>
16 #include <linux/spi/spi.h>
17 #include <linux/i2c.h>
18
19 /* RX-6110 Register definitions */
20 #define RX6110_REG_SEC 0x10
21 #define RX6110_REG_MIN 0x11
22 #define RX6110_REG_HOUR 0x12
23 #define RX6110_REG_WDAY 0x13
24 #define RX6110_REG_MDAY 0x14
25 #define RX6110_REG_MONTH 0x15
26 #define RX6110_REG_YEAR 0x16
27 #define RX6110_REG_RES1 0x17
28 #define RX6110_REG_ALMIN 0x18
29 #define RX6110_REG_ALHOUR 0x19
30 #define RX6110_REG_ALWDAY 0x1A
31 #define RX6110_REG_TCOUNT0 0x1B
32 #define RX6110_REG_TCOUNT1 0x1C
33 #define RX6110_REG_EXT 0x1D
34 #define RX6110_REG_FLAG 0x1E
35 #define RX6110_REG_CTRL 0x1F
36 #define RX6110_REG_USER0 0x20
37 #define RX6110_REG_USER1 0x21
38 #define RX6110_REG_USER2 0x22
39 #define RX6110_REG_USER3 0x23
40 #define RX6110_REG_USER4 0x24
41 #define RX6110_REG_USER5 0x25
42 #define RX6110_REG_USER6 0x26
43 #define RX6110_REG_USER7 0x27
44 #define RX6110_REG_USER8 0x28
45 #define RX6110_REG_USER9 0x29
46 #define RX6110_REG_USERA 0x2A
47 #define RX6110_REG_USERB 0x2B
48 #define RX6110_REG_USERC 0x2C
49 #define RX6110_REG_USERD 0x2D
50 #define RX6110_REG_USERE 0x2E
51 #define RX6110_REG_USERF 0x2F
52 #define RX6110_REG_RES2 0x30
53 #define RX6110_REG_RES3 0x31
54 #define RX6110_REG_IRQ 0x32
55
56 #define RX6110_BIT_ALARM_EN BIT(7)
57
58 /* Extension Register (1Dh) bit positions */
59 #define RX6110_BIT_EXT_TSEL0 BIT(0)
60 #define RX6110_BIT_EXT_TSEL1 BIT(1)
61 #define RX6110_BIT_EXT_TSEL2 BIT(2)
62 #define RX6110_BIT_EXT_WADA BIT(3)
63 #define RX6110_BIT_EXT_TE BIT(4)
64 #define RX6110_BIT_EXT_USEL BIT(5)
65 #define RX6110_BIT_EXT_FSEL0 BIT(6)
66 #define RX6110_BIT_EXT_FSEL1 BIT(7)
67
68 /* Flag Register (1Eh) bit positions */
69 #define RX6110_BIT_FLAG_VLF BIT(1)
70 #define RX6110_BIT_FLAG_AF BIT(3)
71 #define RX6110_BIT_FLAG_TF BIT(4)
72 #define RX6110_BIT_FLAG_UF BIT(5)
73
74 /* Control Register (1Fh) bit positions */
75 #define RX6110_BIT_CTRL_TBKE BIT(0)
76 #define RX6110_BIT_CTRL_TBKON BIT(1)
77 #define RX6110_BIT_CTRL_TSTP BIT(2)
78 #define RX6110_BIT_CTRL_AIE BIT(3)
79 #define RX6110_BIT_CTRL_TIE BIT(4)
80 #define RX6110_BIT_CTRL_UIE BIT(5)
81 #define RX6110_BIT_CTRL_STOP BIT(6)
82 #define RX6110_BIT_CTRL_TEST BIT(7)
83
84 enum {
85 RTC_SEC = 0,
86 RTC_MIN,
87 RTC_HOUR,
88 RTC_WDAY,
89 RTC_MDAY,
90 RTC_MONTH,
91 RTC_YEAR,
92 RTC_NR_TIME
93 };
94
95 #define RX6110_DRIVER_NAME "rx6110"
96
97 struct rx6110_data {
98 struct rtc_device *rtc;
99 struct regmap *regmap;
100 };
101
102 /**
103 * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
104 *
105 * @tm: holds date and time
106 * @data: holds the encoding in rx6110 native form
107 */
rx6110_rtc_tm_to_data(struct rtc_time * tm,u8 * data)108 static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
109 {
110 pr_debug("%s: date %ptRr\n", __func__, tm);
111
112 /*
113 * The year in the RTC is a value between 0 and 99.
114 * Assume that this represents the current century
115 * and disregard all other values.
116 */
117 if (tm->tm_year < 100 || tm->tm_year >= 200)
118 return -EINVAL;
119
120 data[RTC_SEC] = bin2bcd(tm->tm_sec);
121 data[RTC_MIN] = bin2bcd(tm->tm_min);
122 data[RTC_HOUR] = bin2bcd(tm->tm_hour);
123 data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
124 data[RTC_MDAY] = bin2bcd(tm->tm_mday);
125 data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
126 data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
127
128 return 0;
129 }
130
131 /**
132 * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
133 *
134 * @data: holds the encoding in rx6110 native form
135 * @tm: holds date and time
136 */
rx6110_data_to_rtc_tm(u8 * data,struct rtc_time * tm)137 static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
138 {
139 tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
140 tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
141 /* only 24-hour clock */
142 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
143 tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
144 tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
145 tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
146 tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
147
148 pr_debug("%s: date %ptRr\n", __func__, tm);
149
150 /*
151 * The year in the RTC is a value between 0 and 99.
152 * Assume that this represents the current century
153 * and disregard all other values.
154 */
155 if (tm->tm_year < 100 || tm->tm_year >= 200)
156 return -EINVAL;
157
158 return 0;
159 }
160
161 /**
162 * rx6110_set_time - set the current time in the rx6110 registers
163 *
164 * @dev: the rtc device in use
165 * @tm: holds date and time
166 *
167 * BUG: The HW assumes every year that is a multiple of 4 to be a leap
168 * year. Next time this is wrong is 2100, which will not be a leap year
169 *
170 * Note: If STOP is not set/cleared, the clock will start when the seconds
171 * register is written
172 *
173 */
rx6110_set_time(struct device * dev,struct rtc_time * tm)174 static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
175 {
176 struct rx6110_data *rx6110 = dev_get_drvdata(dev);
177 u8 data[RTC_NR_TIME];
178 int ret;
179
180 ret = rx6110_rtc_tm_to_data(tm, data);
181 if (ret < 0)
182 return ret;
183
184 /* set STOP bit before changing clock/calendar */
185 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
186 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
187 if (ret)
188 return ret;
189
190 ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
191 RTC_NR_TIME);
192 if (ret)
193 return ret;
194
195 /* The time in the RTC is valid. Be sure to have VLF cleared. */
196 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
197 RX6110_BIT_FLAG_VLF, 0);
198 if (ret)
199 return ret;
200
201 /* clear STOP bit after changing clock/calendar */
202 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
203 RX6110_BIT_CTRL_STOP, 0);
204
205 return ret;
206 }
207
208 /**
209 * rx6110_get_time - get the current time from the rx6110 registers
210 * @dev: the rtc device in use
211 * @tm: holds date and time
212 */
rx6110_get_time(struct device * dev,struct rtc_time * tm)213 static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
214 {
215 struct rx6110_data *rx6110 = dev_get_drvdata(dev);
216 u8 data[RTC_NR_TIME];
217 int flags;
218 int ret;
219
220 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
221 if (ret)
222 return -EINVAL;
223
224 /* check for VLF Flag (set at power-on) */
225 if ((flags & RX6110_BIT_FLAG_VLF)) {
226 dev_warn(dev, "Voltage low, data is invalid.\n");
227 return -EINVAL;
228 }
229
230 /* read registers to date */
231 ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
232 RTC_NR_TIME);
233 if (ret)
234 return ret;
235
236 ret = rx6110_data_to_rtc_tm(data, tm);
237 if (ret)
238 return ret;
239
240 dev_dbg(dev, "%s: date %ptRr\n", __func__, tm);
241
242 return 0;
243 }
244
245 static const struct reg_sequence rx6110_default_regs[] = {
246 { RX6110_REG_RES1, 0xB8 },
247 { RX6110_REG_RES2, 0x00 },
248 { RX6110_REG_RES3, 0x10 },
249 { RX6110_REG_IRQ, 0x00 },
250 { RX6110_REG_ALMIN, 0x00 },
251 { RX6110_REG_ALHOUR, 0x00 },
252 { RX6110_REG_ALWDAY, 0x00 },
253 };
254
255 /**
256 * rx6110_init - initialize the rx6110 registers
257 *
258 * @rx6110: pointer to the rx6110 struct in use
259 *
260 */
rx6110_init(struct rx6110_data * rx6110)261 static int rx6110_init(struct rx6110_data *rx6110)
262 {
263 struct rtc_device *rtc = rx6110->rtc;
264 int flags;
265 int ret;
266
267 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
268 RX6110_BIT_EXT_TE, 0);
269 if (ret)
270 return ret;
271
272 ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
273 ARRAY_SIZE(rx6110_default_regs));
274 if (ret)
275 return ret;
276
277 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
278 if (ret)
279 return ret;
280
281 /* check for VLF Flag (set at power-on) */
282 if ((flags & RX6110_BIT_FLAG_VLF))
283 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
284
285 /* check for Alarm Flag */
286 if (flags & RX6110_BIT_FLAG_AF)
287 dev_warn(&rtc->dev, "An alarm may have been missed.\n");
288
289 /* check for Periodic Timer Flag */
290 if (flags & RX6110_BIT_FLAG_TF)
291 dev_warn(&rtc->dev, "Periodic timer was detected\n");
292
293 /* check for Update Timer Flag */
294 if (flags & RX6110_BIT_FLAG_UF)
295 dev_warn(&rtc->dev, "Update timer was detected\n");
296
297 /* clear all flags BUT VLF */
298 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
299 RX6110_BIT_FLAG_AF |
300 RX6110_BIT_FLAG_UF |
301 RX6110_BIT_FLAG_TF,
302 0);
303
304 return ret;
305 }
306
307 static const struct rtc_class_ops rx6110_rtc_ops = {
308 .read_time = rx6110_get_time,
309 .set_time = rx6110_set_time,
310 };
311
rx6110_probe(struct rx6110_data * rx6110,struct device * dev)312 static int rx6110_probe(struct rx6110_data *rx6110, struct device *dev)
313 {
314 int err;
315
316 rx6110->rtc = devm_rtc_device_register(dev,
317 RX6110_DRIVER_NAME,
318 &rx6110_rtc_ops, THIS_MODULE);
319
320 if (IS_ERR(rx6110->rtc))
321 return PTR_ERR(rx6110->rtc);
322
323 err = rx6110_init(rx6110);
324 if (err)
325 return err;
326
327 rx6110->rtc->max_user_freq = 1;
328
329 return 0;
330 }
331
332 #if IS_ENABLED(CONFIG_SPI_MASTER)
333 static const struct regmap_config regmap_spi_config = {
334 .reg_bits = 8,
335 .val_bits = 8,
336 .max_register = RX6110_REG_IRQ,
337 .read_flag_mask = 0x80,
338 };
339
340 /**
341 * rx6110_spi_probe - initialize rtc driver
342 * @spi: pointer to spi device
343 */
rx6110_spi_probe(struct spi_device * spi)344 static int rx6110_spi_probe(struct spi_device *spi)
345 {
346 struct rx6110_data *rx6110;
347
348 if ((spi->bits_per_word && spi->bits_per_word != 8) ||
349 (spi->max_speed_hz > 2000000) ||
350 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
351 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
352 spi->bits_per_word, spi->max_speed_hz, spi->mode);
353 dev_warn(&spi->dev, "driving device in an unsupported mode");
354 }
355
356 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
357 if (!rx6110)
358 return -ENOMEM;
359
360 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config);
361 if (IS_ERR(rx6110->regmap)) {
362 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
363 return PTR_ERR(rx6110->regmap);
364 }
365
366 spi_set_drvdata(spi, rx6110);
367
368 return rx6110_probe(rx6110, &spi->dev);
369 }
370
371 static const struct spi_device_id rx6110_spi_id[] = {
372 { "rx6110", 0 },
373 { }
374 };
375 MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
376
377 static const __maybe_unused struct of_device_id rx6110_spi_of_match[] = {
378 { .compatible = "epson,rx6110" },
379 { },
380 };
381 MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
382
383 static struct spi_driver rx6110_spi_driver = {
384 .driver = {
385 .name = RX6110_DRIVER_NAME,
386 .of_match_table = of_match_ptr(rx6110_spi_of_match),
387 },
388 .probe = rx6110_spi_probe,
389 .id_table = rx6110_spi_id,
390 };
391
rx6110_spi_register(void)392 static int rx6110_spi_register(void)
393 {
394 return spi_register_driver(&rx6110_spi_driver);
395 }
396
rx6110_spi_unregister(void)397 static void rx6110_spi_unregister(void)
398 {
399 spi_unregister_driver(&rx6110_spi_driver);
400 }
401 #else
rx6110_spi_register(void)402 static int rx6110_spi_register(void)
403 {
404 return 0;
405 }
406
rx6110_spi_unregister(void)407 static void rx6110_spi_unregister(void)
408 {
409 }
410 #endif /* CONFIG_SPI_MASTER */
411
412 #if IS_ENABLED(CONFIG_I2C)
413 static const struct regmap_config regmap_i2c_config = {
414 .reg_bits = 8,
415 .val_bits = 8,
416 .max_register = RX6110_REG_IRQ,
417 .read_flag_mask = 0x80,
418 };
419
rx6110_i2c_probe(struct i2c_client * client)420 static int rx6110_i2c_probe(struct i2c_client *client)
421 {
422 struct i2c_adapter *adapter = client->adapter;
423 struct rx6110_data *rx6110;
424
425 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
426 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
427 dev_err(&adapter->dev,
428 "doesn't support required functionality\n");
429 return -EIO;
430 }
431
432 rx6110 = devm_kzalloc(&client->dev, sizeof(*rx6110), GFP_KERNEL);
433 if (!rx6110)
434 return -ENOMEM;
435
436 rx6110->regmap = devm_regmap_init_i2c(client, ®map_i2c_config);
437 if (IS_ERR(rx6110->regmap)) {
438 dev_err(&client->dev, "regmap init failed for rtc rx6110\n");
439 return PTR_ERR(rx6110->regmap);
440 }
441
442 i2c_set_clientdata(client, rx6110);
443
444 return rx6110_probe(rx6110, &client->dev);
445 }
446
447 static const struct acpi_device_id rx6110_i2c_acpi_match[] = {
448 { "SECC6110" },
449 { }
450 };
451 MODULE_DEVICE_TABLE(acpi, rx6110_i2c_acpi_match);
452
453 static const struct i2c_device_id rx6110_i2c_id[] = {
454 { "rx6110" },
455 { }
456 };
457 MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
458
459 static struct i2c_driver rx6110_i2c_driver = {
460 .driver = {
461 .name = RX6110_DRIVER_NAME,
462 .acpi_match_table = rx6110_i2c_acpi_match,
463 },
464 .probe = rx6110_i2c_probe,
465 .id_table = rx6110_i2c_id,
466 };
467
rx6110_i2c_register(void)468 static int rx6110_i2c_register(void)
469 {
470 return i2c_add_driver(&rx6110_i2c_driver);
471 }
472
rx6110_i2c_unregister(void)473 static void rx6110_i2c_unregister(void)
474 {
475 i2c_del_driver(&rx6110_i2c_driver);
476 }
477 #else
rx6110_i2c_register(void)478 static int rx6110_i2c_register(void)
479 {
480 return 0;
481 }
482
rx6110_i2c_unregister(void)483 static void rx6110_i2c_unregister(void)
484 {
485 }
486 #endif /* CONFIG_I2C */
487
rx6110_module_init(void)488 static int __init rx6110_module_init(void)
489 {
490 int ret;
491
492 ret = rx6110_spi_register();
493 if (ret)
494 return ret;
495
496 ret = rx6110_i2c_register();
497 if (ret)
498 rx6110_spi_unregister();
499
500 return ret;
501 }
502 module_init(rx6110_module_init);
503
rx6110_module_exit(void)504 static void __exit rx6110_module_exit(void)
505 {
506 rx6110_spi_unregister();
507 rx6110_i2c_unregister();
508 }
509 module_exit(rx6110_module_exit);
510
511 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
512 MODULE_DESCRIPTION("RX-6110 SA RTC driver");
513 MODULE_LICENSE("GPL");
514