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