xref: /openbmc/linux/drivers/rtc/rtc-rx6110.c (revision 48144c28)
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 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, &regmap_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 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, &regmap_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", 0 },
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