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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
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
85enum {
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
98struct 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 */
109static 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 */
138static 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 */
175static 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 */
214static 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
246static 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 */
262static 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
308static const struct rtc_class_ops rx6110_rtc_ops = {
309 .read_time = rx6110_get_time,
310 .set_time = rx6110_set_time,
311};
312
313static struct regmap_config regmap_spi_config = {
314 .reg_bits = 8,
315 .val_bits = 8,
316 .max_register = RX6110_REG_IRQ,
317 .read_flag_mask = 0x80,
318};
319
320/**
321 * rx6110_probe - initialize rtc driver
322 * @spi: pointer to spi device
323 */
324static int rx6110_probe(struct spi_device *spi)
325{
326 struct rx6110_data *rx6110;
327 int err;
328
329 if ((spi->bits_per_word && spi->bits_per_word != 8) ||
330 (spi->max_speed_hz > 2000000) ||
331 (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) {
332 dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n",
333 spi->bits_per_word, spi->max_speed_hz, spi->mode);
334 dev_warn(&spi->dev, "driving device in an unsupported mode");
335 }
336
337 rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL);
338 if (!rx6110)
339 return -ENOMEM;
340
341 rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config);
342 if (IS_ERR(rx6110->regmap)) {
343 dev_err(&spi->dev, "regmap init failed for rtc rx6110\n");
344 return PTR_ERR(rx6110->regmap);
345 }
346
347 spi_set_drvdata(spi, rx6110);
348
349 rx6110->rtc = devm_rtc_device_register(&spi->dev,
350 RX6110_DRIVER_NAME,
351 &rx6110_rtc_ops, THIS_MODULE);
352
353 if (IS_ERR(rx6110->rtc))
354 return PTR_ERR(rx6110->rtc);
355
356 err = rx6110_init(rx6110);
357 if (err)
358 return err;
359
360 rx6110->rtc->max_user_freq = 1;
361
362 return 0;
363}
364
365static const struct spi_device_id rx6110_id[] = {
366 { "rx6110", 0 },
367 { }
368};
369MODULE_DEVICE_TABLE(spi, rx6110_id);
370
371static const struct of_device_id rx6110_spi_of_match[] = {
372 { .compatible = "epson,rx6110" },
373 { },
374};
375MODULE_DEVICE_TABLE(of, rx6110_spi_of_match);
376
377static struct spi_driver rx6110_driver = {
378 .driver = {
379 .name = RX6110_DRIVER_NAME,
380 .of_match_table = of_match_ptr(rx6110_spi_of_match),
381 },
382 .probe = rx6110_probe,
383 .id_table = rx6110_id,
384};
385
386module_spi_driver(rx6110_driver);
387
388MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>");
389MODULE_DESCRIPTION("RX-6110 SA RTC driver");
390MODULE_LICENSE("GPL");