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
84enum {
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
97struct 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 */
108static 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 */
137static 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 */
174static 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 */
213static 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
245static 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 */
261static 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
307static const struct rtc_class_ops rx6110_rtc_ops = {
308	.read_time = rx6110_get_time,
309	.set_time = rx6110_set_time,
310};
311
312static 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)
333static 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 */
344static 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
371static const struct spi_device_id rx6110_spi_id[] = {
372	{ "rx6110", 0 },
373	{ }
374};
375MODULE_DEVICE_TABLE(spi, rx6110_spi_id);
376
377static const __maybe_unused struct of_device_id rx6110_spi_of_match[] = {
378	{ .compatible = "epson,rx6110" },
379	{ },
380};
381MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
382
383static 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
392static int rx6110_spi_register(void)
393{
394	return spi_register_driver(&rx6110_spi_driver);
395}
396
397static void rx6110_spi_unregister(void)
398{
399	spi_unregister_driver(&rx6110_spi_driver);
400}
401#else
402static int rx6110_spi_register(void)
403{
404	return 0;
405}
406
407static void rx6110_spi_unregister(void)
408{
409}
410#endif /* CONFIG_SPI_MASTER */
411
412#if IS_ENABLED(CONFIG_I2C)
413static 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
420static 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
447static const struct acpi_device_id rx6110_i2c_acpi_match[] = {
448	{ "SECC6110" },
449	{ }
450};
451MODULE_DEVICE_TABLE(acpi, rx6110_i2c_acpi_match);
452
453static const struct i2c_device_id rx6110_i2c_id[] = {
454	{ "rx6110", 0 },
455	{ }
456};
457MODULE_DEVICE_TABLE(i2c, rx6110_i2c_id);
458
459static 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
468static int rx6110_i2c_register(void)
469{
470	return i2c_add_driver(&rx6110_i2c_driver);
471}
472
473static void rx6110_i2c_unregister(void)
474{
475	i2c_del_driver(&rx6110_i2c_driver);
476}
477#else
478static int rx6110_i2c_register(void)
479{
480	return 0;
481}
482
483static void rx6110_i2c_unregister(void)
484{
485}
486#endif /* CONFIG_I2C */
487
488static 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}
502module_init(rx6110_module_init);
503
504static void __exit rx6110_module_exit(void)
505{
506	rx6110_spi_unregister();
507	rx6110_i2c_unregister();
508}
509module_exit(rx6110_module_exit);
510
511MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
512MODULE_DESCRIPTION("RX-6110 SA RTC driver");
513MODULE_LICENSE("GPL");
514