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68298c2d ST |
1 | /* |
2 | * Driver for the Epson RTC module RX-6110 SA | |
3 | * | |
4 | * Copyright(C) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de> | |
5 | * Copyright(C) SEIKO EPSON CORPORATION 2013. All rights reserved. | |
6 | * | |
7 | * This driver software is distributed as is, without any warranty of any kind, | |
8 | * either express or implied as further specified in the GNU Public License. | |
9 | * This software may be used and distributed according to the terms of the GNU | |
10 | * Public License, version 2 as published by the Free Software Foundation. | |
11 | * See the file COPYING in the main directory of this archive for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | ||
17 | #include <linux/bcd.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/of_gpio.h> | |
22 | #include <linux/regmap.h> | |
23 | #include <linux/rtc.h> | |
f9bf089a DG |
24 | #include <linux/of.h> |
25 | #include <linux/of_device.h> | |
68298c2d ST |
26 | #include <linux/spi/spi.h> |
27 | ||
28 | /* RX-6110 Register definitions */ | |
29 | #define RX6110_REG_SEC 0x10 | |
30 | #define RX6110_REG_MIN 0x11 | |
31 | #define RX6110_REG_HOUR 0x12 | |
32 | #define RX6110_REG_WDAY 0x13 | |
33 | #define RX6110_REG_MDAY 0x14 | |
34 | #define RX6110_REG_MONTH 0x15 | |
35 | #define RX6110_REG_YEAR 0x16 | |
36 | #define RX6110_REG_RES1 0x17 | |
37 | #define RX6110_REG_ALMIN 0x18 | |
38 | #define RX6110_REG_ALHOUR 0x19 | |
39 | #define RX6110_REG_ALWDAY 0x1A | |
40 | #define RX6110_REG_TCOUNT0 0x1B | |
41 | #define RX6110_REG_TCOUNT1 0x1C | |
42 | #define RX6110_REG_EXT 0x1D | |
43 | #define RX6110_REG_FLAG 0x1E | |
44 | #define RX6110_REG_CTRL 0x1F | |
45 | #define RX6110_REG_USER0 0x20 | |
46 | #define RX6110_REG_USER1 0x21 | |
47 | #define RX6110_REG_USER2 0x22 | |
48 | #define RX6110_REG_USER3 0x23 | |
49 | #define RX6110_REG_USER4 0x24 | |
50 | #define RX6110_REG_USER5 0x25 | |
51 | #define RX6110_REG_USER6 0x26 | |
52 | #define RX6110_REG_USER7 0x27 | |
53 | #define RX6110_REG_USER8 0x28 | |
54 | #define RX6110_REG_USER9 0x29 | |
55 | #define RX6110_REG_USERA 0x2A | |
56 | #define RX6110_REG_USERB 0x2B | |
57 | #define RX6110_REG_USERC 0x2C | |
58 | #define RX6110_REG_USERD 0x2D | |
59 | #define RX6110_REG_USERE 0x2E | |
60 | #define RX6110_REG_USERF 0x2F | |
61 | #define RX6110_REG_RES2 0x30 | |
62 | #define RX6110_REG_RES3 0x31 | |
63 | #define RX6110_REG_IRQ 0x32 | |
64 | ||
65 | #define RX6110_BIT_ALARM_EN BIT(7) | |
66 | ||
67 | /* Extension Register (1Dh) bit positions */ | |
68 | #define RX6110_BIT_EXT_TSEL0 BIT(0) | |
69 | #define RX6110_BIT_EXT_TSEL1 BIT(1) | |
70 | #define RX6110_BIT_EXT_TSEL2 BIT(2) | |
71 | #define RX6110_BIT_EXT_WADA BIT(3) | |
72 | #define RX6110_BIT_EXT_TE BIT(4) | |
73 | #define RX6110_BIT_EXT_USEL BIT(5) | |
74 | #define RX6110_BIT_EXT_FSEL0 BIT(6) | |
75 | #define RX6110_BIT_EXT_FSEL1 BIT(7) | |
76 | ||
77 | /* Flag Register (1Eh) bit positions */ | |
78 | #define RX6110_BIT_FLAG_VLF BIT(1) | |
79 | #define RX6110_BIT_FLAG_AF BIT(3) | |
80 | #define RX6110_BIT_FLAG_TF BIT(4) | |
81 | #define RX6110_BIT_FLAG_UF BIT(5) | |
82 | ||
83 | /* Control Register (1Fh) bit positions */ | |
84 | #define RX6110_BIT_CTRL_TBKE BIT(0) | |
85 | #define RX6110_BIT_CTRL_TBKON BIT(1) | |
86 | #define RX6110_BIT_CTRL_TSTP BIT(2) | |
87 | #define RX6110_BIT_CTRL_AIE BIT(3) | |
88 | #define RX6110_BIT_CTRL_TIE BIT(4) | |
89 | #define RX6110_BIT_CTRL_UIE BIT(5) | |
90 | #define RX6110_BIT_CTRL_STOP BIT(6) | |
91 | #define RX6110_BIT_CTRL_TEST BIT(7) | |
92 | ||
93 | enum { | |
94 | RTC_SEC = 0, | |
95 | RTC_MIN, | |
96 | RTC_HOUR, | |
97 | RTC_WDAY, | |
98 | RTC_MDAY, | |
99 | RTC_MONTH, | |
100 | RTC_YEAR, | |
101 | RTC_NR_TIME | |
102 | }; | |
103 | ||
104 | #define RX6110_DRIVER_NAME "rx6110" | |
105 | ||
106 | struct rx6110_data { | |
107 | struct rtc_device *rtc; | |
108 | struct regmap *regmap; | |
109 | }; | |
110 | ||
111 | /** | |
112 | * rx6110_rtc_tm_to_data - convert rtc_time to native time encoding | |
113 | * | |
114 | * @tm: holds date and time | |
115 | * @data: holds the encoding in rx6110 native form | |
116 | */ | |
117 | static int rx6110_rtc_tm_to_data(struct rtc_time *tm, u8 *data) | |
118 | { | |
a3f60bb3 | 119 | pr_debug("%s: date %ptRr\n", __func__, tm); |
68298c2d ST |
120 | |
121 | /* | |
122 | * The year in the RTC is a value between 0 and 99. | |
123 | * Assume that this represents the current century | |
124 | * and disregard all other values. | |
125 | */ | |
126 | if (tm->tm_year < 100 || tm->tm_year >= 200) | |
127 | return -EINVAL; | |
128 | ||
129 | data[RTC_SEC] = bin2bcd(tm->tm_sec); | |
130 | data[RTC_MIN] = bin2bcd(tm->tm_min); | |
131 | data[RTC_HOUR] = bin2bcd(tm->tm_hour); | |
132 | data[RTC_WDAY] = BIT(bin2bcd(tm->tm_wday)); | |
133 | data[RTC_MDAY] = bin2bcd(tm->tm_mday); | |
134 | data[RTC_MONTH] = bin2bcd(tm->tm_mon + 1); | |
135 | data[RTC_YEAR] = bin2bcd(tm->tm_year % 100); | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | /** | |
141 | * rx6110_data_to_rtc_tm - convert native time encoding to rtc_time | |
142 | * | |
143 | * @data: holds the encoding in rx6110 native form | |
144 | * @tm: holds date and time | |
145 | */ | |
146 | static int rx6110_data_to_rtc_tm(u8 *data, struct rtc_time *tm) | |
147 | { | |
148 | tm->tm_sec = bcd2bin(data[RTC_SEC] & 0x7f); | |
149 | tm->tm_min = bcd2bin(data[RTC_MIN] & 0x7f); | |
150 | /* only 24-hour clock */ | |
151 | tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f); | |
152 | tm->tm_wday = ffs(data[RTC_WDAY] & 0x7f); | |
153 | tm->tm_mday = bcd2bin(data[RTC_MDAY] & 0x3f); | |
154 | tm->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1f) - 1; | |
155 | tm->tm_year = bcd2bin(data[RTC_YEAR]) + 100; | |
156 | ||
a3f60bb3 | 157 | pr_debug("%s: date %ptRr\n", __func__, tm); |
68298c2d ST |
158 | |
159 | /* | |
160 | * The year in the RTC is a value between 0 and 99. | |
161 | * Assume that this represents the current century | |
162 | * and disregard all other values. | |
163 | */ | |
164 | if (tm->tm_year < 100 || tm->tm_year >= 200) | |
165 | return -EINVAL; | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
170 | /** | |
171 | * rx6110_set_time - set the current time in the rx6110 registers | |
172 | * | |
173 | * @dev: the rtc device in use | |
174 | * @tm: holds date and time | |
175 | * | |
176 | * BUG: The HW assumes every year that is a multiple of 4 to be a leap | |
177 | * year. Next time this is wrong is 2100, which will not be a leap year | |
178 | * | |
179 | * Note: If STOP is not set/cleared, the clock will start when the seconds | |
180 | * register is written | |
181 | * | |
182 | */ | |
183 | static int rx6110_set_time(struct device *dev, struct rtc_time *tm) | |
184 | { | |
185 | struct rx6110_data *rx6110 = dev_get_drvdata(dev); | |
186 | u8 data[RTC_NR_TIME]; | |
187 | int ret; | |
188 | ||
189 | ret = rx6110_rtc_tm_to_data(tm, data); | |
190 | if (ret < 0) | |
191 | return ret; | |
192 | ||
193 | /* set STOP bit before changing clock/calendar */ | |
194 | ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, | |
195 | RX6110_BIT_CTRL_STOP, RX6110_BIT_CTRL_STOP); | |
196 | if (ret) | |
197 | return ret; | |
198 | ||
199 | ret = regmap_bulk_write(rx6110->regmap, RX6110_REG_SEC, data, | |
200 | RTC_NR_TIME); | |
201 | if (ret) | |
202 | return ret; | |
203 | ||
204 | /* The time in the RTC is valid. Be sure to have VLF cleared. */ | |
205 | ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, | |
206 | RX6110_BIT_FLAG_VLF, 0); | |
207 | if (ret) | |
208 | return ret; | |
209 | ||
210 | /* clear STOP bit after changing clock/calendar */ | |
211 | ret = regmap_update_bits(rx6110->regmap, RX6110_REG_CTRL, | |
212 | RX6110_BIT_CTRL_STOP, 0); | |
213 | ||
214 | return ret; | |
215 | } | |
216 | ||
217 | /** | |
218 | * rx6110_get_time - get the current time from the rx6110 registers | |
219 | * @dev: the rtc device in use | |
220 | * @tm: holds date and time | |
221 | */ | |
222 | static int rx6110_get_time(struct device *dev, struct rtc_time *tm) | |
223 | { | |
224 | struct rx6110_data *rx6110 = dev_get_drvdata(dev); | |
225 | u8 data[RTC_NR_TIME]; | |
226 | int flags; | |
227 | int ret; | |
228 | ||
229 | ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); | |
230 | if (ret) | |
231 | return -EINVAL; | |
232 | ||
233 | /* check for VLF Flag (set at power-on) */ | |
234 | if ((flags & RX6110_BIT_FLAG_VLF)) { | |
235 | dev_warn(dev, "Voltage low, data is invalid.\n"); | |
236 | return -EINVAL; | |
237 | } | |
238 | ||
239 | /* read registers to date */ | |
240 | ret = regmap_bulk_read(rx6110->regmap, RX6110_REG_SEC, data, | |
241 | RTC_NR_TIME); | |
242 | if (ret) | |
243 | return ret; | |
244 | ||
245 | ret = rx6110_data_to_rtc_tm(data, tm); | |
246 | if (ret) | |
247 | return ret; | |
248 | ||
a3f60bb3 | 249 | dev_dbg(dev, "%s: date %ptRr\n", __func__, tm); |
68298c2d | 250 | |
22652ba7 | 251 | return 0; |
68298c2d ST |
252 | } |
253 | ||
254 | static const struct reg_sequence rx6110_default_regs[] = { | |
255 | { RX6110_REG_RES1, 0xB8 }, | |
256 | { RX6110_REG_RES2, 0x00 }, | |
257 | { RX6110_REG_RES3, 0x10 }, | |
258 | { RX6110_REG_IRQ, 0x00 }, | |
259 | { RX6110_REG_ALMIN, 0x00 }, | |
260 | { RX6110_REG_ALHOUR, 0x00 }, | |
261 | { RX6110_REG_ALWDAY, 0x00 }, | |
262 | }; | |
263 | ||
264 | /** | |
265 | * rx6110_init - initialize the rx6110 registers | |
266 | * | |
267 | * @rx6110: pointer to the rx6110 struct in use | |
268 | * | |
269 | */ | |
270 | static int rx6110_init(struct rx6110_data *rx6110) | |
271 | { | |
272 | struct rtc_device *rtc = rx6110->rtc; | |
273 | int flags; | |
274 | int ret; | |
275 | ||
276 | ret = regmap_update_bits(rx6110->regmap, RX6110_REG_EXT, | |
277 | RX6110_BIT_EXT_TE, 0); | |
278 | if (ret) | |
279 | return ret; | |
280 | ||
281 | ret = regmap_register_patch(rx6110->regmap, rx6110_default_regs, | |
282 | ARRAY_SIZE(rx6110_default_regs)); | |
283 | if (ret) | |
284 | return ret; | |
285 | ||
286 | ret = regmap_read(rx6110->regmap, RX6110_REG_FLAG, &flags); | |
287 | if (ret) | |
288 | return ret; | |
289 | ||
290 | /* check for VLF Flag (set at power-on) */ | |
291 | if ((flags & RX6110_BIT_FLAG_VLF)) | |
292 | dev_warn(&rtc->dev, "Voltage low, data loss detected.\n"); | |
293 | ||
294 | /* check for Alarm Flag */ | |
295 | if (flags & RX6110_BIT_FLAG_AF) | |
296 | dev_warn(&rtc->dev, "An alarm may have been missed.\n"); | |
297 | ||
298 | /* check for Periodic Timer Flag */ | |
299 | if (flags & RX6110_BIT_FLAG_TF) | |
300 | dev_warn(&rtc->dev, "Periodic timer was detected\n"); | |
301 | ||
302 | /* check for Update Timer Flag */ | |
303 | if (flags & RX6110_BIT_FLAG_UF) | |
304 | dev_warn(&rtc->dev, "Update timer was detected\n"); | |
305 | ||
306 | /* clear all flags BUT VLF */ | |
307 | ret = regmap_update_bits(rx6110->regmap, RX6110_REG_FLAG, | |
308 | RX6110_BIT_FLAG_AF | | |
309 | RX6110_BIT_FLAG_UF | | |
310 | RX6110_BIT_FLAG_TF, | |
311 | 0); | |
312 | ||
313 | return ret; | |
314 | } | |
315 | ||
34c7b3ac | 316 | static const struct rtc_class_ops rx6110_rtc_ops = { |
68298c2d ST |
317 | .read_time = rx6110_get_time, |
318 | .set_time = rx6110_set_time, | |
319 | }; | |
320 | ||
321 | static struct regmap_config regmap_spi_config = { | |
322 | .reg_bits = 8, | |
323 | .val_bits = 8, | |
324 | .max_register = RX6110_REG_IRQ, | |
325 | .read_flag_mask = 0x80, | |
326 | }; | |
327 | ||
328 | /** | |
329 | * rx6110_probe - initialize rtc driver | |
330 | * @spi: pointer to spi device | |
331 | */ | |
332 | static int rx6110_probe(struct spi_device *spi) | |
333 | { | |
334 | struct rx6110_data *rx6110; | |
335 | int err; | |
336 | ||
337 | if ((spi->bits_per_word && spi->bits_per_word != 8) || | |
338 | (spi->max_speed_hz > 2000000) || | |
339 | (spi->mode != (SPI_CS_HIGH | SPI_CPOL | SPI_CPHA))) { | |
340 | dev_warn(&spi->dev, "SPI settings: bits_per_word: %d, max_speed_hz: %d, mode: %xh\n", | |
341 | spi->bits_per_word, spi->max_speed_hz, spi->mode); | |
342 | dev_warn(&spi->dev, "driving device in an unsupported mode"); | |
343 | } | |
344 | ||
345 | rx6110 = devm_kzalloc(&spi->dev, sizeof(*rx6110), GFP_KERNEL); | |
346 | if (!rx6110) | |
347 | return -ENOMEM; | |
348 | ||
349 | rx6110->regmap = devm_regmap_init_spi(spi, ®map_spi_config); | |
350 | if (IS_ERR(rx6110->regmap)) { | |
351 | dev_err(&spi->dev, "regmap init failed for rtc rx6110\n"); | |
352 | return PTR_ERR(rx6110->regmap); | |
353 | } | |
354 | ||
355 | spi_set_drvdata(spi, rx6110); | |
356 | ||
357 | rx6110->rtc = devm_rtc_device_register(&spi->dev, | |
358 | RX6110_DRIVER_NAME, | |
359 | &rx6110_rtc_ops, THIS_MODULE); | |
360 | ||
361 | if (IS_ERR(rx6110->rtc)) | |
362 | return PTR_ERR(rx6110->rtc); | |
363 | ||
364 | err = rx6110_init(rx6110); | |
365 | if (err) | |
366 | return err; | |
367 | ||
368 | rx6110->rtc->max_user_freq = 1; | |
369 | ||
370 | return 0; | |
371 | } | |
372 | ||
373 | static int rx6110_remove(struct spi_device *spi) | |
374 | { | |
375 | return 0; | |
376 | } | |
377 | ||
378 | static const struct spi_device_id rx6110_id[] = { | |
379 | { "rx6110", 0 }, | |
380 | { } | |
381 | }; | |
382 | MODULE_DEVICE_TABLE(spi, rx6110_id); | |
383 | ||
f9bf089a DG |
384 | static const struct of_device_id rx6110_spi_of_match[] = { |
385 | { .compatible = "epson,rx6110" }, | |
386 | { }, | |
387 | }; | |
388 | MODULE_DEVICE_TABLE(of, rx6110_spi_of_match); | |
389 | ||
68298c2d ST |
390 | static struct spi_driver rx6110_driver = { |
391 | .driver = { | |
392 | .name = RX6110_DRIVER_NAME, | |
f9bf089a | 393 | .of_match_table = of_match_ptr(rx6110_spi_of_match), |
68298c2d ST |
394 | }, |
395 | .probe = rx6110_probe, | |
396 | .remove = rx6110_remove, | |
397 | .id_table = rx6110_id, | |
398 | }; | |
399 | ||
400 | module_spi_driver(rx6110_driver); | |
401 | ||
402 | MODULE_AUTHOR("Val Krutov <val.krutov@erd.epson.com>"); | |
403 | MODULE_DESCRIPTION("RX-6110 SA RTC driver"); | |
404 | MODULE_LICENSE("GPL"); |