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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * rtc-fm3130.c - RTC driver for Ramtron FM3130 I2C chip.
4 *
5 * Copyright (C) 2008 Sergey Lapin
6 * Based on ds1307 driver by James Chapman and David Brownell
7 */
8
9#include <linux/module.h>
10#include <linux/i2c.h>
11#include <linux/rtc.h>
12#include <linux/bcd.h>
13#include <linux/slab.h>
14
15#define FM3130_RTC_CONTROL (0x0)
16#define FM3130_CAL_CONTROL (0x1)
17#define FM3130_RTC_SECONDS (0x2)
18#define FM3130_RTC_MINUTES (0x3)
19#define FM3130_RTC_HOURS (0x4)
20#define FM3130_RTC_DAY (0x5)
21#define FM3130_RTC_DATE (0x6)
22#define FM3130_RTC_MONTHS (0x7)
23#define FM3130_RTC_YEARS (0x8)
24
25#define FM3130_ALARM_SECONDS (0x9)
26#define FM3130_ALARM_MINUTES (0xa)
27#define FM3130_ALARM_HOURS (0xb)
28#define FM3130_ALARM_DATE (0xc)
29#define FM3130_ALARM_MONTHS (0xd)
30#define FM3130_ALARM_WP_CONTROL (0xe)
31
32#define FM3130_CAL_CONTROL_BIT_nOSCEN (1 << 7) /* Osciallator enabled */
33#define FM3130_RTC_CONTROL_BIT_LB (1 << 7) /* Low battery */
34#define FM3130_RTC_CONTROL_BIT_AF (1 << 6) /* Alarm flag */
35#define FM3130_RTC_CONTROL_BIT_CF (1 << 5) /* Century overflow */
36#define FM3130_RTC_CONTROL_BIT_POR (1 << 4) /* Power on reset */
37#define FM3130_RTC_CONTROL_BIT_AEN (1 << 3) /* Alarm enable */
38#define FM3130_RTC_CONTROL_BIT_CAL (1 << 2) /* Calibration mode */
39#define FM3130_RTC_CONTROL_BIT_WRITE (1 << 1) /* W=1 -> write mode W=0 normal */
40#define FM3130_RTC_CONTROL_BIT_READ (1 << 0) /* R=1 -> read mode R=0 normal */
41
42#define FM3130_CLOCK_REGS 7
43#define FM3130_ALARM_REGS 5
44
45struct fm3130 {
46 u8 reg_addr_time;
47 u8 reg_addr_alarm;
48 u8 regs[15];
49 struct i2c_msg msg[4];
50 struct i2c_client *client;
51 struct rtc_device *rtc;
52 int alarm_valid;
53 int data_valid;
54};
55static const struct i2c_device_id fm3130_id[] = {
56 { .name = "fm3130" },
57 { }
58};
59MODULE_DEVICE_TABLE(i2c, fm3130_id);
60
61#define FM3130_MODE_NORMAL 0
62#define FM3130_MODE_WRITE 1
63#define FM3130_MODE_READ 2
64
65static void fm3130_rtc_mode(struct device *dev, int mode)
66{
67 struct fm3130 *fm3130 = dev_get_drvdata(dev);
68
69 fm3130->regs[FM3130_RTC_CONTROL] =
70 i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
71 switch (mode) {
72 case FM3130_MODE_NORMAL:
73 fm3130->regs[FM3130_RTC_CONTROL] &=
74 ~(FM3130_RTC_CONTROL_BIT_WRITE |
75 FM3130_RTC_CONTROL_BIT_READ);
76 break;
77 case FM3130_MODE_WRITE:
78 fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_WRITE;
79 break;
80 case FM3130_MODE_READ:
81 fm3130->regs[FM3130_RTC_CONTROL] |= FM3130_RTC_CONTROL_BIT_READ;
82 break;
83 default:
84 dev_dbg(dev, "invalid mode %d\n", mode);
85 break;
86 }
87
88 i2c_smbus_write_byte_data(fm3130->client,
89 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL]);
90}
91
92static int fm3130_get_time(struct device *dev, struct rtc_time *t)
93{
94 struct fm3130 *fm3130 = dev_get_drvdata(dev);
95 int tmp;
96
97 if (!fm3130->data_valid) {
98 /* We have invalid data in RTC, probably due
99 to battery faults or other problems. Return EIO
100 for now, it will allow us to set data later instead
101 of error during probing which disables device */
102 return -EIO;
103 }
104 fm3130_rtc_mode(dev, FM3130_MODE_READ);
105
106 /* read the RTC date and time registers all at once */
107 tmp = i2c_transfer(fm3130->client->adapter, fm3130->msg, 2);
108 if (tmp != 2) {
109 dev_err(dev, "%s error %d\n", "read", tmp);
110 return -EIO;
111 }
112
113 fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
114
115 dev_dbg(dev, "%s: %15ph\n", "read", fm3130->regs);
116
117 t->tm_sec = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
118 t->tm_min = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
119 tmp = fm3130->regs[FM3130_RTC_HOURS] & 0x3f;
120 t->tm_hour = bcd2bin(tmp);
121 t->tm_wday = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x07) - 1;
122 t->tm_mday = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
123 tmp = fm3130->regs[FM3130_RTC_MONTHS] & 0x1f;
124 t->tm_mon = bcd2bin(tmp) - 1;
125
126 /* assume 20YY not 19YY, and ignore CF bit */
127 t->tm_year = bcd2bin(fm3130->regs[FM3130_RTC_YEARS]) + 100;
128
129 dev_dbg(dev, "%s secs=%d, mins=%d, "
130 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
131 "read", t->tm_sec, t->tm_min,
132 t->tm_hour, t->tm_mday,
133 t->tm_mon, t->tm_year, t->tm_wday);
134
135 return 0;
136}
137
138
139static int fm3130_set_time(struct device *dev, struct rtc_time *t)
140{
141 struct fm3130 *fm3130 = dev_get_drvdata(dev);
142 int tmp, i;
143 u8 *buf = fm3130->regs;
144
145 dev_dbg(dev, "%s secs=%d, mins=%d, "
146 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
147 "write", t->tm_sec, t->tm_min,
148 t->tm_hour, t->tm_mday,
149 t->tm_mon, t->tm_year, t->tm_wday);
150
151 /* first register addr */
152 buf[FM3130_RTC_SECONDS] = bin2bcd(t->tm_sec);
153 buf[FM3130_RTC_MINUTES] = bin2bcd(t->tm_min);
154 buf[FM3130_RTC_HOURS] = bin2bcd(t->tm_hour);
155 buf[FM3130_RTC_DAY] = bin2bcd(t->tm_wday + 1);
156 buf[FM3130_RTC_DATE] = bin2bcd(t->tm_mday);
157 buf[FM3130_RTC_MONTHS] = bin2bcd(t->tm_mon + 1);
158
159 /* assume 20YY not 19YY */
160 tmp = t->tm_year - 100;
161 buf[FM3130_RTC_YEARS] = bin2bcd(tmp);
162
163 dev_dbg(dev, "%s: %15ph\n", "write", buf);
164
165 fm3130_rtc_mode(dev, FM3130_MODE_WRITE);
166
167 /* Writing time registers, we don't support multibyte transfers */
168 for (i = 0; i < FM3130_CLOCK_REGS; i++) {
169 i2c_smbus_write_byte_data(fm3130->client,
170 FM3130_RTC_SECONDS + i,
171 fm3130->regs[FM3130_RTC_SECONDS + i]);
172 }
173
174 fm3130_rtc_mode(dev, FM3130_MODE_NORMAL);
175
176 /* We assume here that data are valid once written */
177 if (!fm3130->data_valid)
178 fm3130->data_valid = 1;
179 return 0;
180}
181
182static int fm3130_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
183{
184 struct fm3130 *fm3130 = dev_get_drvdata(dev);
185 int tmp;
186 struct rtc_time *tm = &alrm->time;
187
188 if (!fm3130->alarm_valid) {
189 /*
190 * We have invalid alarm in RTC, probably due to battery faults
191 * or other problems. Return EIO for now, it will allow us to
192 * set alarm value later instead of error during probing which
193 * disables device
194 */
195 return -EIO;
196 }
197
198 /* read the RTC alarm registers all at once */
199 tmp = i2c_transfer(fm3130->client->adapter, &fm3130->msg[2], 2);
200 if (tmp != 2) {
201 dev_err(dev, "%s error %d\n", "read", tmp);
202 return -EIO;
203 }
204 dev_dbg(dev, "alarm read %02x %02x %02x %02x %02x\n",
205 fm3130->regs[FM3130_ALARM_SECONDS],
206 fm3130->regs[FM3130_ALARM_MINUTES],
207 fm3130->regs[FM3130_ALARM_HOURS],
208 fm3130->regs[FM3130_ALARM_DATE],
209 fm3130->regs[FM3130_ALARM_MONTHS]);
210
211 tm->tm_sec = bcd2bin(fm3130->regs[FM3130_ALARM_SECONDS] & 0x7F);
212 tm->tm_min = bcd2bin(fm3130->regs[FM3130_ALARM_MINUTES] & 0x7F);
213 tm->tm_hour = bcd2bin(fm3130->regs[FM3130_ALARM_HOURS] & 0x3F);
214 tm->tm_mday = bcd2bin(fm3130->regs[FM3130_ALARM_DATE] & 0x3F);
215 tm->tm_mon = bcd2bin(fm3130->regs[FM3130_ALARM_MONTHS] & 0x1F);
216
217 if (tm->tm_mon > 0)
218 tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
219
220 dev_dbg(dev, "%s secs=%d, mins=%d, "
221 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
222 "read alarm", tm->tm_sec, tm->tm_min,
223 tm->tm_hour, tm->tm_mday,
224 tm->tm_mon, tm->tm_year, tm->tm_wday);
225
226 /* check if alarm enabled */
227 fm3130->regs[FM3130_RTC_CONTROL] =
228 i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
229
230 if ((fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_AEN) &&
231 (~fm3130->regs[FM3130_RTC_CONTROL] &
232 FM3130_RTC_CONTROL_BIT_CAL)) {
233 alrm->enabled = 1;
234 }
235
236 return 0;
237}
238
239static int fm3130_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
240{
241 struct fm3130 *fm3130 = dev_get_drvdata(dev);
242 struct rtc_time *tm = &alrm->time;
243 int i;
244
245 dev_dbg(dev, "%s secs=%d, mins=%d, "
246 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
247 "write alarm", tm->tm_sec, tm->tm_min,
248 tm->tm_hour, tm->tm_mday,
249 tm->tm_mon, tm->tm_year, tm->tm_wday);
250
251 fm3130->regs[FM3130_ALARM_SECONDS] =
252 (tm->tm_sec != -1) ? bin2bcd(tm->tm_sec) : 0x80;
253
254 fm3130->regs[FM3130_ALARM_MINUTES] =
255 (tm->tm_min != -1) ? bin2bcd(tm->tm_min) : 0x80;
256
257 fm3130->regs[FM3130_ALARM_HOURS] =
258 (tm->tm_hour != -1) ? bin2bcd(tm->tm_hour) : 0x80;
259
260 fm3130->regs[FM3130_ALARM_DATE] =
261 (tm->tm_mday != -1) ? bin2bcd(tm->tm_mday) : 0x80;
262
263 fm3130->regs[FM3130_ALARM_MONTHS] =
264 (tm->tm_mon != -1) ? bin2bcd(tm->tm_mon + 1) : 0x80;
265
266 dev_dbg(dev, "alarm write %02x %02x %02x %02x %02x\n",
267 fm3130->regs[FM3130_ALARM_SECONDS],
268 fm3130->regs[FM3130_ALARM_MINUTES],
269 fm3130->regs[FM3130_ALARM_HOURS],
270 fm3130->regs[FM3130_ALARM_DATE],
271 fm3130->regs[FM3130_ALARM_MONTHS]);
272 /* Writing time registers, we don't support multibyte transfers */
273 for (i = 0; i < FM3130_ALARM_REGS; i++) {
274 i2c_smbus_write_byte_data(fm3130->client,
275 FM3130_ALARM_SECONDS + i,
276 fm3130->regs[FM3130_ALARM_SECONDS + i]);
277 }
278 fm3130->regs[FM3130_RTC_CONTROL] =
279 i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
280
281 /* enable or disable alarm */
282 if (alrm->enabled) {
283 i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
284 (fm3130->regs[FM3130_RTC_CONTROL] &
285 ~(FM3130_RTC_CONTROL_BIT_CAL)) |
286 FM3130_RTC_CONTROL_BIT_AEN);
287 } else {
288 i2c_smbus_write_byte_data(fm3130->client, FM3130_RTC_CONTROL,
289 fm3130->regs[FM3130_RTC_CONTROL] &
290 ~(FM3130_RTC_CONTROL_BIT_CAL) &
291 ~(FM3130_RTC_CONTROL_BIT_AEN));
292 }
293
294 /* We assume here that data is valid once written */
295 if (!fm3130->alarm_valid)
296 fm3130->alarm_valid = 1;
297
298 return 0;
299}
300
301static int fm3130_alarm_irq_enable(struct device *dev, unsigned int enabled)
302{
303 struct fm3130 *fm3130 = dev_get_drvdata(dev);
304 int ret = 0;
305
306 fm3130->regs[FM3130_RTC_CONTROL] =
307 i2c_smbus_read_byte_data(fm3130->client, FM3130_RTC_CONTROL);
308
309 dev_dbg(dev, "alarm_irq_enable: enable=%d, FM3130_RTC_CONTROL=%02x\n",
310 enabled, fm3130->regs[FM3130_RTC_CONTROL]);
311
312 switch (enabled) {
313 case 0: /* alarm off */
314 ret = i2c_smbus_write_byte_data(fm3130->client,
315 FM3130_RTC_CONTROL, fm3130->regs[FM3130_RTC_CONTROL] &
316 ~(FM3130_RTC_CONTROL_BIT_CAL) &
317 ~(FM3130_RTC_CONTROL_BIT_AEN));
318 break;
319 case 1: /* alarm on */
320 ret = i2c_smbus_write_byte_data(fm3130->client,
321 FM3130_RTC_CONTROL, (fm3130->regs[FM3130_RTC_CONTROL] &
322 ~(FM3130_RTC_CONTROL_BIT_CAL)) |
323 FM3130_RTC_CONTROL_BIT_AEN);
324 break;
325 default:
326 ret = -EINVAL;
327 break;
328 }
329
330 return ret;
331}
332
333static const struct rtc_class_ops fm3130_rtc_ops = {
334 .read_time = fm3130_get_time,
335 .set_time = fm3130_set_time,
336 .read_alarm = fm3130_read_alarm,
337 .set_alarm = fm3130_set_alarm,
338 .alarm_irq_enable = fm3130_alarm_irq_enable,
339};
340
341static struct i2c_driver fm3130_driver;
342
343static int fm3130_probe(struct i2c_client *client)
344{
345 struct fm3130 *fm3130;
346 int err = -ENODEV;
347 int tmp;
348 struct i2c_adapter *adapter = client->adapter;
349
350 if (!i2c_check_functionality(adapter,
351 I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
352 return -EIO;
353
354 fm3130 = devm_kzalloc(&client->dev, sizeof(struct fm3130), GFP_KERNEL);
355
356 if (!fm3130)
357 return -ENOMEM;
358
359 fm3130->client = client;
360 i2c_set_clientdata(client, fm3130);
361 fm3130->reg_addr_time = FM3130_RTC_SECONDS;
362 fm3130->reg_addr_alarm = FM3130_ALARM_SECONDS;
363
364 /* Messages to read time */
365 fm3130->msg[0].addr = client->addr;
366 fm3130->msg[0].flags = 0;
367 fm3130->msg[0].len = 1;
368 fm3130->msg[0].buf = &fm3130->reg_addr_time;
369
370 fm3130->msg[1].addr = client->addr;
371 fm3130->msg[1].flags = I2C_M_RD;
372 fm3130->msg[1].len = FM3130_CLOCK_REGS;
373 fm3130->msg[1].buf = &fm3130->regs[FM3130_RTC_SECONDS];
374
375 /* Messages to read alarm */
376 fm3130->msg[2].addr = client->addr;
377 fm3130->msg[2].flags = 0;
378 fm3130->msg[2].len = 1;
379 fm3130->msg[2].buf = &fm3130->reg_addr_alarm;
380
381 fm3130->msg[3].addr = client->addr;
382 fm3130->msg[3].flags = I2C_M_RD;
383 fm3130->msg[3].len = FM3130_ALARM_REGS;
384 fm3130->msg[3].buf = &fm3130->regs[FM3130_ALARM_SECONDS];
385
386 fm3130->alarm_valid = 0;
387 fm3130->data_valid = 0;
388
389 tmp = i2c_transfer(adapter, fm3130->msg, 4);
390 if (tmp != 4) {
391 dev_dbg(&client->dev, "read error %d\n", tmp);
392 err = -EIO;
393 goto exit_free;
394 }
395
396 fm3130->regs[FM3130_RTC_CONTROL] =
397 i2c_smbus_read_byte_data(client, FM3130_RTC_CONTROL);
398 fm3130->regs[FM3130_CAL_CONTROL] =
399 i2c_smbus_read_byte_data(client, FM3130_CAL_CONTROL);
400
401 /* Disabling calibration mode */
402 if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_CAL) {
403 i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
404 fm3130->regs[FM3130_RTC_CONTROL] &
405 ~(FM3130_RTC_CONTROL_BIT_CAL));
406 dev_warn(&client->dev, "Disabling calibration mode!\n");
407 }
408
409 /* Disabling read and write modes */
410 if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_WRITE ||
411 fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_READ) {
412 i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
413 fm3130->regs[FM3130_RTC_CONTROL] &
414 ~(FM3130_RTC_CONTROL_BIT_READ |
415 FM3130_RTC_CONTROL_BIT_WRITE));
416 dev_warn(&client->dev, "Disabling READ or WRITE mode!\n");
417 }
418
419 /* oscillator off? turn it on, so clock can tick. */
420 if (fm3130->regs[FM3130_CAL_CONTROL] & FM3130_CAL_CONTROL_BIT_nOSCEN)
421 i2c_smbus_write_byte_data(client, FM3130_CAL_CONTROL,
422 fm3130->regs[FM3130_CAL_CONTROL] &
423 ~(FM3130_CAL_CONTROL_BIT_nOSCEN));
424
425 /* low battery? clear flag, and warn */
426 if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_LB) {
427 i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
428 fm3130->regs[FM3130_RTC_CONTROL] &
429 ~(FM3130_RTC_CONTROL_BIT_LB));
430 dev_warn(&client->dev, "Low battery!\n");
431 }
432
433 /* check if Power On Reset bit is set */
434 if (fm3130->regs[FM3130_RTC_CONTROL] & FM3130_RTC_CONTROL_BIT_POR) {
435 i2c_smbus_write_byte_data(client, FM3130_RTC_CONTROL,
436 fm3130->regs[FM3130_RTC_CONTROL] &
437 ~FM3130_RTC_CONTROL_BIT_POR);
438 dev_dbg(&client->dev, "POR bit is set\n");
439 }
440 /* ACS is controlled by alarm */
441 i2c_smbus_write_byte_data(client, FM3130_ALARM_WP_CONTROL, 0x80);
442
443 /* alarm registers sanity check */
444 tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
445 if (tmp > 59)
446 goto bad_alarm;
447
448 tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
449 if (tmp > 59)
450 goto bad_alarm;
451
452 tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
453 if (tmp > 23)
454 goto bad_alarm;
455
456 tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
457 if (tmp == 0 || tmp > 31)
458 goto bad_alarm;
459
460 tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
461 if (tmp == 0 || tmp > 12)
462 goto bad_alarm;
463
464 fm3130->alarm_valid = 1;
465
466bad_alarm:
467
468 /* clock registers sanity chek */
469 tmp = bcd2bin(fm3130->regs[FM3130_RTC_SECONDS] & 0x7f);
470 if (tmp > 59)
471 goto bad_clock;
472
473 tmp = bcd2bin(fm3130->regs[FM3130_RTC_MINUTES] & 0x7f);
474 if (tmp > 59)
475 goto bad_clock;
476
477 tmp = bcd2bin(fm3130->regs[FM3130_RTC_HOURS] & 0x3f);
478 if (tmp > 23)
479 goto bad_clock;
480
481 tmp = bcd2bin(fm3130->regs[FM3130_RTC_DAY] & 0x7);
482 if (tmp == 0 || tmp > 7)
483 goto bad_clock;
484
485 tmp = bcd2bin(fm3130->regs[FM3130_RTC_DATE] & 0x3f);
486 if (tmp == 0 || tmp > 31)
487 goto bad_clock;
488
489 tmp = bcd2bin(fm3130->regs[FM3130_RTC_MONTHS] & 0x1f);
490 if (tmp == 0 || tmp > 12)
491 goto bad_clock;
492
493 fm3130->data_valid = 1;
494
495bad_clock:
496
497 if (!fm3130->data_valid || !fm3130->alarm_valid)
498 dev_dbg(&client->dev, "%s: %15ph\n", "bogus registers",
499 fm3130->regs);
500
501 /* We won't bail out here because we just got invalid data.
502 Time setting from u-boot doesn't work anyway */
503 fm3130->rtc = devm_rtc_device_register(&client->dev, client->name,
504 &fm3130_rtc_ops, THIS_MODULE);
505 if (IS_ERR(fm3130->rtc)) {
506 err = PTR_ERR(fm3130->rtc);
507 dev_err(&client->dev,
508 "unable to register the class device\n");
509 goto exit_free;
510 }
511 return 0;
512exit_free:
513 return err;
514}
515
516static struct i2c_driver fm3130_driver = {
517 .driver = {
518 .name = "rtc-fm3130",
519 },
520 .probe = fm3130_probe,
521 .id_table = fm3130_id,
522};
523
524module_i2c_driver(fm3130_driver);
525
526MODULE_DESCRIPTION("RTC driver for FM3130");
527MODULE_AUTHOR("Sergey Lapin <[email protected]>");
528MODULE_LICENSE("GPL");
529