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