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/of_gpio.h>
14 #include <linux/regmap.h>
15 #include <linux/rtc.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/spi/spi.h>
19 #include <linux/i2c.h>
20
21 /* RX-6110 Register definitions */
22 #define RX6110_REG_SEC 0x10
23 #define RX6110_REG_MIN 0x11
24 #define RX6110_REG_HOUR 0x12
25 #define RX6110_REG_WDAY 0x13
26 #define RX6110_REG_MDAY 0x14
27 #define RX6110_REG_MONTH 0x15
28 #define RX6110_REG_YEAR 0x16
29 #define RX6110_REG_RES1 0x17
30 #define RX6110_REG_ALMIN 0x18
31 #define RX6110_REG_ALHOUR 0x19
32 #define RX6110_REG_ALWDAY 0x1A
33 #define RX6110_REG_TCOUNT0 0x1B
34 #define RX6110_REG_TCOUNT1 0x1C
35 #define RX6110_REG_EXT 0x1D
36 #define RX6110_REG_FLAG 0x1E
37 #define RX6110_REG_CTRL 0x1F
38 #define RX6110_REG_USER0 0x20
39 #define RX6110_REG_USER1 0x21
40 #define RX6110_REG_USER2 0x22
41 #define RX6110_REG_USER3 0x23
42 #define RX6110_REG_USER4 0x24
43 #define RX6110_REG_USER5 0x25
44 #define RX6110_REG_USER6 0x26
45 #define RX6110_REG_USER7 0x27
46 #define RX6110_REG_USER8 0x28
47 #define RX6110_REG_USER9 0x29
48 #define RX6110_REG_USERA 0x2A
49 #define RX6110_REG_USERB 0x2B
50 #define RX6110_REG_USERC 0x2C
51 #define RX6110_REG_USERD 0x2D
52 #define RX6110_REG_USERE 0x2E
53 #define RX6110_REG_USERF 0x2F
54 #define RX6110_REG_RES2 0x30
55 #define RX6110_REG_RES3 0x31
56 #define RX6110_REG_IRQ 0x32
57
58 #define RX6110_BIT_ALARM_EN BIT(7)
59
60 /* Extension Register (1Dh) bit positions */
61 #define RX6110_BIT_EXT_TSEL0 BIT(0)
62 #define RX6110_BIT_EXT_TSEL1 BIT(1)
63 #define RX6110_BIT_EXT_TSEL2 BIT(2)
64 #define RX6110_BIT_EXT_WADA BIT(3)
65 #define RX6110_BIT_EXT_TE BIT(4)
66 #define RX6110_BIT_EXT_USEL BIT(5)
67 #define RX6110_BIT_EXT_FSEL0 BIT(6)
68 #define RX6110_BIT_EXT_FSEL1 BIT(7)
69
70 /* Flag Register (1Eh) bit positions */
71 #define RX6110_BIT_FLAG_VLF BIT(1)
72 #define RX6110_BIT_FLAG_AF BIT(3)
73 #define RX6110_BIT_FLAG_TF BIT(4)
74 #define RX6110_BIT_FLAG_UF BIT(5)
75
76 /* Control Register (1Fh) bit positions */
77 #define RX6110_BIT_CTRL_TBKE BIT(0)
78 #define RX6110_BIT_CTRL_TBKON BIT(1)
79 #define RX6110_BIT_CTRL_TSTP BIT(2)
80 #define RX6110_BIT_CTRL_AIE BIT(3)
81 #define RX6110_BIT_CTRL_TIE BIT(4)
82 #define RX6110_BIT_CTRL_UIE BIT(5)
83 #define RX6110_BIT_CTRL_STOP BIT(6)
84 #define RX6110_BIT_CTRL_TEST BIT(7)
85
86 enum {
87 RTC_SEC = 0,
88 RTC_MIN,
89 RTC_HOUR,
90 RTC_WDAY,
91 RTC_MDAY,
92 RTC_MONTH,
93 RTC_YEAR,
94 RTC_NR_TIME
95 };
96
97 #define RX6110_DRIVER_NAME "rx6110"
98
99 struct rx6110_data {
100 struct rtc_device *rtc;
101 struct regmap *regmap;
102 };
103
104 /**
105 * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding
106 *
107 * @tm: holds date and time
108 * @data: holds the encoding in rx6110 native form
109 */
rx6110_rtc_tm_to_data(struct rtc_time * tm,u8 * data)110 static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
111 {
112 pr_debug("%s: date %ptRr\n", __func__, tm);
113
114 /*
115 * The year in the RTC is a value between 0 and 99.
116 * Assume that this represents the current century
117 * and disregard all other values.
118 */
119 if (tm->tm_year < 100 || tm->tm_year >= 200)
120 return -EINVAL;
121
122 data[RTC_SEC] = bin2bcd(tm->tm_sec);
123 data[RTC_MIN] = bin2bcd(tm->tm_min);
124 data[RTC_HOUR] = bin2bcd(tm->tm_hour);
125 data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday));
126 data[RTC_MDAY] = bin2bcd(tm->tm_mday);
127 data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
128 data[RTC_YEAR] = bin2bcd(tm->tm_year % 100);
129
130 return 0;
131 }
132
133 /**
134 * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time
135 *
136 * @data: holds the encoding in rx6110 native form
137 * @tm: holds date and time
138 */
rx6110_data_to_rtc_tm(u8 * data,struct rtc_time * tm)139 static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm)
140 {
141 tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f);
142 tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f);
143 /* only 24-hour clock */
144 tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
145 tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f);
146 tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f);
147 tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1;
148 tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100;
149
150 pr_debug("%s: date %ptRr\n", __func__, tm);
151
152 /*
153 * The year in the RTC is a value between 0 and 99.
154 * Assume that this represents the current century
155 * and disregard all other values.
156 */
157 if (tm->tm_year < 100 || tm->tm_year >= 200)
158 return -EINVAL;
159
160 return 0;
161 }
162
163 /**
164 * rx6110_set_time - set the current time in the rx6110 registers
165 *
166 * @dev: the rtc device in use
167 * @tm: holds date and time
168 *
169 * BUG: The HW assumes every year that is a multiple of 4 to be a leap
170 * year. Next time this is wrong is 2100, which will not be a leap year
171 *
172 * Note: If STOP is not set/cleared, the clock will start when the seconds
173 * register is written
174 *
175 */
rx6110_set_time(struct device * dev,struct rtc_time * tm)176 static int rx6110_set_time(struct device *dev, struct rtc_time *tm)
177 {
178 struct rx6110_data *rx6110 = dev_get_drvdata(dev);
179 u8 data[RTC_NR_TIME];
180 int ret;
181
182 ret = rx6110_rtc_tm_to_data(tm, data);
183 if (ret < 0)
184 return ret;
185
186 /* set STOP bit before changing clock/calendar */
187 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
188 RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP);
189 if (ret)
190 return ret;
191
192 ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data,
193 RTC_NR_TIME);
194 if (ret)
195 return ret;
196
197 /* The time in the RTC is valid. Be sure to have VLF cleared. */
198 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
199 RX6110_BIT_FLAG_VLF, 0);
200 if (ret)
201 return ret;
202
203 /* clear STOP bit after changing clock/calendar */
204 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL,
205 RX6110_BIT_CTRL_STOP, 0);
206
207 return ret;
208 }
209
210 /**
211 * rx6110_get_time - get the current time from the rx6110 registers
212 * @dev: the rtc device in use
213 * @tm: holds date and time
214 */
rx6110_get_time(struct device * dev,struct rtc_time * tm)215 static int rx6110_get_time(struct device *dev, struct rtc_time *tm)
216 {
217 struct rx6110_data *rx6110 = dev_get_drvdata(dev);
218 u8 data[RTC_NR_TIME];
219 int flags;
220 int ret;
221
222 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
223 if (ret)
224 return -EINVAL;
225
226 /* check for VLF Flag (set at power-on) */
227 if ((flags & RX6110_BIT_FLAG_VLF)) {
228 dev_warn(dev, "Voltage low, data is invalid.\n");
229 return -EINVAL;
230 }
231
232 /* read registers to date */
233 ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data,
234 RTC_NR_TIME);
235 if (ret)
236 return ret;
237
238 ret = rx6110_data_to_rtc_tm(data, tm);
239 if (ret)
240 return ret;
241
242 dev_dbg(dev, "%s: date %ptRr\n", __func__, tm);
243
244 return 0;
245 }
246
247 static const struct reg_sequence rx6110_default_regs[] = {
248 { RX6110_REG_RES1, 0xB8 },
249 { RX6110_REG_RES2, 0x00 },
250 { RX6110_REG_RES3, 0x10 },
251 { RX6110_REG_IRQ, 0x00 },
252 { RX6110_REG_ALMIN, 0x00 },
253 { RX6110_REG_ALHOUR, 0x00 },
254 { RX6110_REG_ALWDAY, 0x00 },
255 };
256
257 /**
258 * rx6110_init - initialize the rx6110 registers
259 *
260 * @rx6110: pointer to the rx6110 struct in use
261 *
262 */
rx6110_init(struct rx6110_data * rx6110)263 static int rx6110_init(struct rx6110_data *rx6110)
264 {
265 struct rtc_device *rtc = rx6110->rtc;
266 int flags;
267 int ret;
268
269 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT,
270 RX6110_BIT_EXT_TE, 0);
271 if (ret)
272 return ret;
273
274 ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs,
275 ARRAY_SIZE(rx6110_default_regs));
276 if (ret)
277 return ret;
278
279 ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags);
280 if (ret)
281 return ret;
282
283 /* check for VLF Flag (set at power-on) */
284 if ((flags & RX6110_BIT_FLAG_VLF))
285 dev_warn(&rtc->dev, "Voltage low, data loss detected.\n");
286
287 /* check for Alarm Flag */
288 if (flags & RX6110_BIT_FLAG_AF)
289 dev_warn(&rtc->dev, "An alarm may have been missed.\n");
290
291 /* check for Periodic Timer Flag */
292 if (flags & RX6110_BIT_FLAG_TF)
293 dev_warn(&rtc->dev, "Periodic timer was detected\n");
294
295 /* check for Update Timer Flag */
296 if (flags & RX6110_BIT_FLAG_UF)
297 dev_warn(&rtc->dev, "Update timer was detected\n");
298
299 /* clear all flags BUT VLF */
300 ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG,
301 RX6110_BIT_FLAG_AF |
302 RX6110_BIT_FLAG_UF |
303 RX6110_BIT_FLAG_TF,
304 0);
305
306 return ret;
307 }
308
309 static const struct rtc_class_ops rx6110_rtc_ops = {
310 .read_time = rx6110_get_time,
311 .set_time = rx6110_set_time,
312 };
313
rx6110_probe(struct rx6110_data * rx6110,struct device * dev)314 static int rx6110_probe(struct rx6110_data *rx6110, struct device *dev)
315 {
316 int err;
317
318 rx6110->rtc = devm_rtc_device_register(dev,
319 RX6110_DRIVER_NAME,
320 &rx6110_rtc_ops, THIS_MODULE);
321
322 if (IS_ERR(rx6110->rtc))
323 return PTR_ERR(rx6110->rtc);
324
325 err = rx6110_init(rx6110);
326 if (err)
327 return err;
328
329 rx6110->rtc->max_user_freq = 1;
330
331 return 0;
332 }
333
334 #if IS_ENABLED(CONFIG_SPI_MASTER)
335 static struct regmap_config regmap_spi_config = {
336 .reg_bits = 8,
337 .val_bits = 8,
338 .max_register = RX6110_REG_IRQ,
339 .read_flag_mask = 0x80,
340 };
341
342 /**
343 * rx6110_spi_probe - initialize rtc driver
344 * @spi: pointer to spi device
345 */
rx6110_spi_probe(struct spi_device * spi)346 static int rx6110_spi_probe(struct spi_device *spi)
347 {
348 struct rx6110_data *rx6110;
349
350 if ((spi->bits_per_word && spi->bits_per_word != 8) ||
351 (spi->max_speed_hz > 2000000) ||
352 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
353 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
354 spi->bits_per_word, spi->max_speed_hz, spi->mode);
355 dev_warn(&spi->dev, "driving device in an unsupported mode");
356 }
357
358 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
359 if (!rx6110)
360 return -ENOMEM;
361
362 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config);
363 if (IS_ERR(rx6110->regmap)) {
364 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
365 return PTR_ERR(rx6110->regmap);
366 }
367
368 spi_set_drvdata(spi, rx6110);
369
370 return rx6110_probe(rx6110, &spi->dev);
371 }
372
373 static const struct spi_device_id rx6110_spi_id[] = {
374 { "rx6110", 0 },
375 { }
376 };
377 MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
378
379 static const struct of_device_id rx6110_spi_of_match[] = {
380 { .compatible = "epson,rx6110" },
381 { },
382 };
383 MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
384
385 static struct spi_driver rx6110_spi_driver = {
386 .driver = {
387 .name = RX6110_DRIVER_NAME,
388 .of_match_table = of_match_ptr(rx6110_spi_of_match),
389 },
390 .probe = rx6110_spi_probe,
391 .id_table = rx6110_spi_id,
392 };
393
rx6110_spi_register(void)394 static int rx6110_spi_register(void)
395 {
396 return spi_register_driver(&rx6110_spi_driver);
397 }
398
rx6110_spi_unregister(void)399 static void rx6110_spi_unregister(void)
400 {
401 spi_unregister_driver(&rx6110_spi_driver);
402 }
403 #else
rx6110_spi_register(void)404 static int rx6110_spi_register(void)
405 {
406 return 0;
407 }
408
rx6110_spi_unregister(void)409 static void rx6110_spi_unregister(void)
410 {
411 }
412 #endif /* CONFIG_SPI_MASTER */
413
414 #if IS_ENABLED(CONFIG_I2C)
415 static struct regmap_config regmap_i2c_config = {
416 .reg_bits = 8,
417 .val_bits = 8,
418 .max_register = RX6110_REG_IRQ,
419 .read_flag_mask = 0x80,
420 };
421
rx6110_i2c_probe(struct i2c_client * client)422 static int rx6110_i2c_probe(struct i2c_client *client)
423 {
424 struct i2c_adapter *adapter = client->adapter;
425 struct rx6110_data *rx6110;
426
427 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
428 | I2C_FUNC_SMBUS_I2C_BLOCK)) {
429 dev_err(&adapter->dev,
430 "doesn't support required functionality\n");
431 return -EIO;
432 }
433
434 rx6110 = devm_kzalloc(&client->dev, sizeof(*rx6110), GFP_KERNEL);
435 if (!rx6110)
436 return -ENOMEM;
437
438 rx6110->regmap = devm_regmap_init_i2c(client, ®map_i2c_config);
439 if (IS_ERR(rx6110->regmap)) {
440 dev_err(&client->dev, "regmap init failed for rtc rx6110\n");
441 return PTR_ERR(rx6110->regmap);
442 }
443
444 i2c_set_clientdata(client, rx6110);
445
446 return rx6110_probe(rx6110, &client->dev);
447 }
448
449 static const struct acpi_device_id rx6110_i2c_acpi_match[] = {
450 { "SECC6110" },
451 { }
452 };
453 MODULE_DEVICE_TABLE(acpi, rx6110_i2c_acpi_match);
454
455 static const struct i2c_device_id rx6110_i2c_id[] = {
456 { "rx6110", 0 },
457 { }
458 };
459 MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
460
461 static struct i2c_driver rx6110_i2c_driver = {
462 .driver = {
463 .name = RX6110_DRIVER_NAME,
464 .acpi_match_table = rx6110_i2c_acpi_match,
465 },
466 .probe_new = rx6110_i2c_probe,
467 .id_table = rx6110_i2c_id,
468 };
469
rx6110_i2c_register(void)470 static int rx6110_i2c_register(void)
471 {
472 return i2c_add_driver(&rx6110_i2c_driver);
473 }
474
rx6110_i2c_unregister(void)475 static void rx6110_i2c_unregister(void)
476 {
477 i2c_del_driver(&rx6110_i2c_driver);
478 }
479 #else
rx6110_i2c_register(void)480 static int rx6110_i2c_register(void)
481 {
482 return 0;
483 }
484
rx6110_i2c_unregister(void)485 static void rx6110_i2c_unregister(void)
486 {
487 }
488 #endif /* CONFIG_I2C */
489
rx6110_module_init(void)490 static int __init rx6110_module_init(void)
491 {
492 int ret;
493
494 ret = rx6110_spi_register();
495 if (ret)
496 return ret;
497
498 ret = rx6110_i2c_register();
499 if (ret)
500 rx6110_spi_unregister();
501
502 return ret;
503 }
504 module_init(rx6110_module_init);
505
rx6110_module_exit(void)506 static void __exit rx6110_module_exit(void)
507 {
508 rx6110_spi_unregister();
509 rx6110_i2c_unregister();
510 }
511 module_exit(rx6110_module_exit);
512
513 MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
514 MODULE_DESCRIPTION("RX-6110 SA RTC driver");
515 MODULE_LICENSE("GPL");
516