xref: /netbsd-src/sys/dev/i2c/ds1307.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1 /*	$NetBSD: ds1307.c,v 1.38 2021/01/27 02:29:48 thorpej Exp $	*/
2 
3 /*
4  * Copyright (c) 2003 Wasabi Systems, Inc.
5  * All rights reserved.
6  *
7  * Written by Steve C. Woodford and Jason R. Thorpe for Wasabi Systems, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *      This product includes software developed for the NetBSD Project by
20  *      Wasabi Systems, Inc.
21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22  *    or promote products derived from this software without specific prior
23  *    written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: ds1307.c,v 1.38 2021/01/27 02:29:48 thorpej Exp $");
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/device.h>
44 #include <sys/kernel.h>
45 #include <sys/fcntl.h>
46 #include <sys/uio.h>
47 #include <sys/conf.h>
48 #include <sys/event.h>
49 
50 #include <dev/clock_subr.h>
51 
52 #include <dev/i2c/i2cvar.h>
53 #include <dev/i2c/ds1307reg.h>
54 #include <dev/sysmon/sysmonvar.h>
55 
56 #include "ioconf.h"
57 #include "opt_dsrtc.h"
58 
59 struct dsrtc_model {
60 	const i2c_addr_t *dm_valid_addrs;
61 	uint16_t dm_model;
62 	uint8_t dm_ch_reg;
63 	uint8_t dm_ch_value;
64 	uint8_t dm_vbaten_reg;
65 	uint8_t dm_vbaten_value;
66 	uint8_t dm_rtc_start;
67 	uint8_t dm_rtc_size;
68 	uint8_t dm_nvram_start;
69 	uint8_t dm_nvram_size;
70 	uint8_t dm_flags;
71 #define	DSRTC_FLAG_CLOCK_HOLD		0x01
72 #define	DSRTC_FLAG_BCD			0x02
73 #define	DSRTC_FLAG_TEMP			0x04
74 #define DSRTC_FLAG_VBATEN		0x08
75 #define	DSRTC_FLAG_YEAR_START_2K	0x10
76 #define	DSRTC_FLAG_CLOCK_HOLD_REVERSED	0x20
77 };
78 
79 static const i2c_addr_t ds1307_valid_addrs[] = { DS1307_ADDR, 0 };
80 static const struct dsrtc_model ds1307_model = {
81 	.dm_valid_addrs = ds1307_valid_addrs,
82 	.dm_model = 1307,
83 	.dm_ch_reg = DSXXXX_SECONDS,
84 	.dm_ch_value = DS1307_SECONDS_CH,
85 	.dm_rtc_start = DS1307_RTC_START,
86 	.dm_rtc_size = DS1307_RTC_SIZE,
87 	.dm_nvram_start = DS1307_NVRAM_START,
88 	.dm_nvram_size = DS1307_NVRAM_SIZE,
89 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_CLOCK_HOLD,
90 };
91 
92 static const struct dsrtc_model ds1339_model = {
93 	.dm_valid_addrs = ds1307_valid_addrs,
94 	.dm_model = 1339,
95 	.dm_rtc_start = DS1339_RTC_START,
96 	.dm_rtc_size = DS1339_RTC_SIZE,
97 	.dm_flags = DSRTC_FLAG_BCD,
98 };
99 
100 static const struct dsrtc_model ds1340_model = {
101 	.dm_valid_addrs = ds1307_valid_addrs,
102 	.dm_model = 1340,
103 	.dm_ch_reg = DSXXXX_SECONDS,
104 	.dm_ch_value = DS1340_SECONDS_EOSC,
105 	.dm_rtc_start = DS1340_RTC_START,
106 	.dm_rtc_size = DS1340_RTC_SIZE,
107 	.dm_flags = DSRTC_FLAG_BCD,
108 };
109 
110 static const struct dsrtc_model ds1672_model = {
111 	.dm_valid_addrs = ds1307_valid_addrs,
112 	.dm_model = 1672,
113 	.dm_rtc_start = DS1672_RTC_START,
114 	.dm_rtc_size = DS1672_RTC_SIZE,
115 	.dm_ch_reg = DS1672_CONTROL,
116 	.dm_ch_value = DS1672_CONTROL_CH,
117 	.dm_flags = 0,
118 };
119 
120 static const struct dsrtc_model ds3231_model = {
121 	.dm_valid_addrs = ds1307_valid_addrs,
122 	.dm_model = 3231,
123 	.dm_rtc_start = DS3232_RTC_START,
124 	.dm_rtc_size = DS3232_RTC_SIZE,
125 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_TEMP,
126 };
127 
128 static const struct dsrtc_model ds3232_model = {
129 	.dm_valid_addrs = ds1307_valid_addrs,
130 	.dm_model = 3232,
131 	.dm_rtc_start = DS3232_RTC_START,
132 	.dm_rtc_size = DS3232_RTC_SIZE,
133 	.dm_nvram_start = DS3232_NVRAM_START,
134 	.dm_nvram_size = DS3232_NVRAM_SIZE,
135 	/*
136 	 * XXX
137 	 * the DS3232 likely has the temperature sensor too but I can't
138 	 * easily verify or test that right now
139 	 */
140 	.dm_flags = DSRTC_FLAG_BCD,
141 };
142 
143 static const i2c_addr_t mcp7940_valid_addrs[] = { MCP7940_ADDR, 0 };
144 static const struct dsrtc_model mcp7940_model = {
145 	.dm_valid_addrs = mcp7940_valid_addrs,
146 	.dm_model = 7940,
147 	.dm_rtc_start = DS1307_RTC_START,
148 	.dm_rtc_size = DS1307_RTC_SIZE,
149 	.dm_ch_reg = DSXXXX_SECONDS,
150 	.dm_ch_value = DS1307_SECONDS_CH,
151 	.dm_vbaten_reg = DSXXXX_DAY,
152 	.dm_vbaten_value = MCP7940_TOD_DAY_VBATEN,
153 	.dm_nvram_start = MCP7940_NVRAM_START,
154 	.dm_nvram_size = MCP7940_NVRAM_SIZE,
155 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_CLOCK_HOLD |
156 		DSRTC_FLAG_VBATEN | DSRTC_FLAG_CLOCK_HOLD_REVERSED,
157 };
158 
159 static const struct device_compatible_entry compat_data[] = {
160 	{ .compat = "dallas,ds1307",		.data = &ds1307_model },
161 	{ .compat = "maxim,ds1307",		.data = &ds1307_model },
162 	{ .compat = "i2c-ds1307",		.data = &ds1307_model },
163 
164 	{ .compat = "dallas,ds1339",		.data = &ds1339_model },
165 	{ .compat = "maxim,ds1339",		.data = &ds1339_model },
166 
167 	{ .compat = "dallas,ds1340",		.data = &ds1340_model },
168 	{ .compat = "maxim,ds1340",		.data = &ds1340_model },
169 
170 	{ .compat = "dallas,ds1672",		.data = &ds1672_model },
171 	{ .compat = "maxim,ds1672",		.data = &ds1672_model },
172 
173 	{ .compat = "dallas,ds3231",		.data = &ds3231_model },
174 	{ .compat = "maxim,ds3231",		.data = &ds3231_model },
175 
176 	{ .compat = "dallas,ds3232",		.data = &ds3232_model },
177 	{ .compat = "maxim,ds3232",		.data = &ds3232_model },
178 
179 	{ .compat = "microchip,mcp7940",	.data = &mcp7940_model },
180 
181 	DEVICE_COMPAT_EOL
182 };
183 
184 struct dsrtc_softc {
185 	device_t sc_dev;
186 	i2c_tag_t sc_tag;
187 	uint8_t sc_address;
188 	bool sc_open;
189 	struct dsrtc_model sc_model;
190 	struct todr_chip_handle sc_todr;
191 	struct sysmon_envsys *sc_sme;
192 	envsys_data_t sc_sensor;
193 };
194 
195 static void	dsrtc_attach(device_t, device_t, void *);
196 static int	dsrtc_match(device_t, cfdata_t, void *);
197 
198 CFATTACH_DECL_NEW(dsrtc, sizeof(struct dsrtc_softc),
199     dsrtc_match, dsrtc_attach, NULL, NULL);
200 
201 dev_type_open(dsrtc_open);
202 dev_type_close(dsrtc_close);
203 dev_type_read(dsrtc_read);
204 dev_type_write(dsrtc_write);
205 
206 const struct cdevsw dsrtc_cdevsw = {
207 	.d_open = dsrtc_open,
208 	.d_close = dsrtc_close,
209 	.d_read = dsrtc_read,
210 	.d_write = dsrtc_write,
211 	.d_ioctl = noioctl,
212 	.d_stop = nostop,
213 	.d_tty = notty,
214 	.d_poll = nopoll,
215 	.d_mmap = nommap,
216 	.d_kqfilter = nokqfilter,
217 	.d_discard = nodiscard,
218 	.d_flag = D_OTHER
219 };
220 
221 static int dsrtc_gettime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
222 static int dsrtc_settime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
223 static int dsrtc_clock_read_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
224 static int dsrtc_clock_write_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
225 
226 static int dsrtc_gettime_timeval(struct todr_chip_handle *, struct timeval *);
227 static int dsrtc_settime_timeval(struct todr_chip_handle *, struct timeval *);
228 static int dsrtc_clock_read_timeval(struct dsrtc_softc *, time_t *);
229 static int dsrtc_clock_write_timeval(struct dsrtc_softc *, time_t);
230 
231 static int dsrtc_read_temp(struct dsrtc_softc *, uint32_t *);
232 static void dsrtc_refresh(struct sysmon_envsys *, envsys_data_t *);
233 
234 static const struct dsrtc_model *
235 dsrtc_model_by_number(u_int model)
236 {
237 	const struct device_compatible_entry *dce;
238 	const struct dsrtc_model *dm;
239 
240 	/* no model given, assume it's a DS1307 */
241 	if (model == 0)
242 		return &ds1307_model;
243 
244 	for (dce = compat_data; dce->compat != NULL; dce++) {
245 		dm = dce->data;
246 		if (dm->dm_model == model)
247 			return dm;
248 	}
249 	return NULL;
250 }
251 
252 static const struct dsrtc_model *
253 dsrtc_model_by_compat(const struct i2c_attach_args *ia)
254 {
255 	const struct dsrtc_model *dm = NULL;
256 	const struct device_compatible_entry *dce;
257 
258 	if ((dce = iic_compatible_lookup(ia, compat_data)) != NULL)
259 		dm = dce->data;
260 
261 	return dm;
262 }
263 
264 static bool
265 dsrtc_is_valid_addr_for_model(const struct dsrtc_model *dm, i2c_addr_t addr)
266 {
267 
268 	for (int i = 0; dm->dm_valid_addrs[i] != 0; i++) {
269 		if (addr == dm->dm_valid_addrs[i])
270 			return true;
271 	}
272 	return false;
273 }
274 
275 static int
276 dsrtc_match(device_t parent, cfdata_t cf, void *arg)
277 {
278 	struct i2c_attach_args *ia = arg;
279 	const struct dsrtc_model *dm;
280 	int match_result;
281 
282 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
283 		return match_result;
284 
285 	dm = dsrtc_model_by_number(cf->cf_flags & 0xffff);
286 	if (dm == NULL)
287 		return 0;
288 
289 	if (dsrtc_is_valid_addr_for_model(dm, ia->ia_addr))
290 		return I2C_MATCH_ADDRESS_ONLY;
291 
292 	return 0;
293 }
294 
295 static void
296 dsrtc_attach(device_t parent, device_t self, void *arg)
297 {
298 	struct dsrtc_softc *sc = device_private(self);
299 	struct i2c_attach_args *ia = arg;
300 	const struct dsrtc_model *dm;
301 	prop_dictionary_t dict = device_properties(self);
302 	bool base_2k = FALSE;
303 
304 	if ((dm = dsrtc_model_by_compat(ia)) == NULL)
305 		dm = dsrtc_model_by_number(device_cfdata(self)->cf_flags);
306 
307 	if (dm == NULL) {
308 		aprint_error(": unable to determine model!\n");
309 		return;
310 	}
311 
312 	aprint_naive(": Real-time Clock%s\n",
313 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
314 	aprint_normal(": DS%u Real-time Clock%s\n", dm->dm_model,
315 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
316 
317 	sc->sc_tag = ia->ia_tag;
318 	sc->sc_address = ia->ia_addr;
319 	sc->sc_model = *dm;
320 	sc->sc_dev = self;
321 	sc->sc_open = 0;
322 	sc->sc_todr.cookie = sc;
323 
324 	if (dm->dm_flags & DSRTC_FLAG_BCD) {
325 		sc->sc_todr.todr_gettime_ymdhms = dsrtc_gettime_ymdhms;
326 		sc->sc_todr.todr_settime_ymdhms = dsrtc_settime_ymdhms;
327 	} else {
328 		sc->sc_todr.todr_gettime = dsrtc_gettime_timeval;
329 		sc->sc_todr.todr_settime = dsrtc_settime_timeval;
330 	}
331 	sc->sc_todr.todr_setwen = NULL;
332 
333 #ifdef DSRTC_YEAR_START_2K
334 	sc->sc_model.dm_flags |= DSRTC_FLAG_YEAR_START_2K;
335 #endif
336 
337 	prop_dictionary_get_bool(dict, "base_year_is_2000", &base_2k);
338 	if (base_2k) sc->sc_model.dm_flags |= DSRTC_FLAG_YEAR_START_2K;
339 
340 
341 	todr_attach(&sc->sc_todr);
342 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) != 0) {
343 		int error;
344 
345 		sc->sc_sme = sysmon_envsys_create();
346 		sc->sc_sme->sme_name = device_xname(self);
347 		sc->sc_sme->sme_cookie = sc;
348 		sc->sc_sme->sme_refresh = dsrtc_refresh;
349 
350 		sc->sc_sensor.units =  ENVSYS_STEMP;
351 		sc->sc_sensor.state = ENVSYS_SINVALID;
352 		sc->sc_sensor.flags = 0;
353 		(void)strlcpy(sc->sc_sensor.desc, "temperature",
354 		    sizeof(sc->sc_sensor.desc));
355 
356 		if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
357 			aprint_error_dev(self, "unable to attach sensor\n");
358 			goto bad;
359 		}
360 
361 		error = sysmon_envsys_register(sc->sc_sme);
362 		if (error) {
363 			aprint_error_dev(self,
364 			    "error %d registering with sysmon\n", error);
365 			goto bad;
366 		}
367 	}
368 	return;
369 bad:
370 	sysmon_envsys_destroy(sc->sc_sme);
371 }
372 
373 /*ARGSUSED*/
374 int
375 dsrtc_open(dev_t dev, int flag, int fmt, struct lwp *l)
376 {
377 	struct dsrtc_softc *sc;
378 
379 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
380 		return ENXIO;
381 
382 	/* XXX: Locking */
383 	if (sc->sc_open)
384 		return EBUSY;
385 
386 	sc->sc_open = true;
387 	return 0;
388 }
389 
390 /*ARGSUSED*/
391 int
392 dsrtc_close(dev_t dev, int flag, int fmt, struct lwp *l)
393 {
394 	struct dsrtc_softc *sc;
395 
396 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
397 		return ENXIO;
398 
399 	sc->sc_open = false;
400 	return 0;
401 }
402 
403 /*ARGSUSED*/
404 int
405 dsrtc_read(dev_t dev, struct uio *uio, int flags)
406 {
407 	struct dsrtc_softc *sc;
408 	int error;
409 
410 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
411 		return ENXIO;
412 
413 	const struct dsrtc_model * const dm = &sc->sc_model;
414 	if (uio->uio_offset >= dm->dm_nvram_size)
415 		return EINVAL;
416 
417 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
418 		return error;
419 
420 	KASSERT(uio->uio_offset >= 0);
421 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
422 		uint8_t ch, cmd;
423 		const u_int a = uio->uio_offset;
424 		cmd = a + dm->dm_nvram_start;
425 		if ((error = iic_exec(sc->sc_tag,
426 		    uio->uio_resid > 1 ? I2C_OP_READ : I2C_OP_READ_WITH_STOP,
427 		    sc->sc_address, &cmd, 1, &ch, 1, 0)) != 0) {
428 			iic_release_bus(sc->sc_tag, 0);
429 			aprint_error_dev(sc->sc_dev,
430 			    "%s: read failed at 0x%x: %d\n",
431 			    __func__, a, error);
432 			return error;
433 		}
434 		if ((error = uiomove(&ch, 1, uio)) != 0) {
435 			iic_release_bus(sc->sc_tag, 0);
436 			return error;
437 		}
438 	}
439 
440 	iic_release_bus(sc->sc_tag, 0);
441 
442 	return 0;
443 }
444 
445 /*ARGSUSED*/
446 int
447 dsrtc_write(dev_t dev, struct uio *uio, int flags)
448 {
449 	struct dsrtc_softc *sc;
450 	int error;
451 
452 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
453 		return ENXIO;
454 
455 	const struct dsrtc_model * const dm = &sc->sc_model;
456 	if (uio->uio_offset >= dm->dm_nvram_size)
457 		return EINVAL;
458 
459 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
460 		return error;
461 
462 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
463 		uint8_t cmdbuf[2];
464 		const u_int a = (int)uio->uio_offset;
465 		cmdbuf[0] = a + dm->dm_nvram_start;
466 		if ((error = uiomove(&cmdbuf[1], 1, uio)) != 0)
467 			break;
468 
469 		if ((error = iic_exec(sc->sc_tag,
470 		    uio->uio_resid ? I2C_OP_WRITE : I2C_OP_WRITE_WITH_STOP,
471 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
472 			aprint_error_dev(sc->sc_dev,
473 			    "%s: write failed at 0x%x: %d\n",
474 			    __func__, a, error);
475 			break;
476 		}
477 	}
478 
479 	iic_release_bus(sc->sc_tag, 0);
480 
481 	return error;
482 }
483 
484 static int
485 dsrtc_gettime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
486 {
487 	struct dsrtc_softc *sc = ch->cookie;
488 	struct clock_ymdhms check;
489 	int retries;
490 
491 	memset(dt, 0, sizeof(*dt));
492 	memset(&check, 0, sizeof(check));
493 
494 	/*
495 	 * Since we don't support Burst Read, we have to read the clock twice
496 	 * until we get two consecutive identical results.
497 	 */
498 	retries = 5;
499 	do {
500 		dsrtc_clock_read_ymdhms(sc, dt);
501 		dsrtc_clock_read_ymdhms(sc, &check);
502 	} while (memcmp(dt, &check, sizeof(check)) != 0 && --retries);
503 
504 	return 0;
505 }
506 
507 static int
508 dsrtc_settime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
509 {
510 	struct dsrtc_softc *sc = ch->cookie;
511 
512 	if (dsrtc_clock_write_ymdhms(sc, dt) == 0)
513 		return -1;
514 
515 	return 0;
516 }
517 
518 static int
519 dsrtc_clock_read_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
520 {
521 	struct dsrtc_model * const dm = &sc->sc_model;
522 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[1];
523 	int error;
524 
525 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
526 
527 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
528 		aprint_error_dev(sc->sc_dev,
529 		    "%s: failed to acquire I2C bus: %d\n",
530 		    __func__, error);
531 		return 0;
532 	}
533 
534 	/* Read each RTC register in order. */
535 	for (u_int i = 0; !error && i < dm->dm_rtc_size; i++) {
536 		cmdbuf[0] = dm->dm_rtc_start + i;
537 
538 		error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
539 		    sc->sc_address, cmdbuf, 1, &bcd[i], 1, 0);
540 	}
541 
542 	/* Done with I2C */
543 	iic_release_bus(sc->sc_tag, 0);
544 
545 	if (error != 0) {
546 		aprint_error_dev(sc->sc_dev,
547 		    "%s: failed to read rtc at 0x%x: %d\n",
548 		    __func__, cmdbuf[0], error);
549 		return 0;
550 	}
551 
552 	/*
553 	 * Convert the RTC's register values into something useable
554 	 */
555 	dt->dt_sec = bcdtobin(bcd[DSXXXX_SECONDS] & DSXXXX_SECONDS_MASK);
556 	dt->dt_min = bcdtobin(bcd[DSXXXX_MINUTES] & DSXXXX_MINUTES_MASK);
557 
558 	if ((bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_MODE) != 0) {
559 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
560 		    DSXXXX_HOURS_12MASK) % 12; /* 12AM -> 0, 12PM -> 12 */
561 		if (bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_PM)
562 			dt->dt_hour += 12;
563 	} else
564 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
565 		    DSXXXX_HOURS_24MASK);
566 
567 	dt->dt_day = bcdtobin(bcd[DSXXXX_DATE] & DSXXXX_DATE_MASK);
568 	dt->dt_mon = bcdtobin(bcd[DSXXXX_MONTH] & DSXXXX_MONTH_MASK);
569 
570 	/* XXX: Should be an MD way to specify EPOCH used by BIOS/Firmware */
571 	if (sc->sc_model.dm_flags & DSRTC_FLAG_YEAR_START_2K)
572 		dt->dt_year = bcdtobin(bcd[DSXXXX_YEAR]) + 2000;
573 	else {
574 		dt->dt_year = bcdtobin(bcd[DSXXXX_YEAR]) + POSIX_BASE_YEAR;
575 		if (bcd[DSXXXX_MONTH] & DSXXXX_MONTH_CENTURY)
576 			dt->dt_year += 100;
577 	}
578 
579 	return 1;
580 }
581 
582 static int
583 dsrtc_clock_write_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
584 {
585 	struct dsrtc_model * const dm = &sc->sc_model;
586 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[2];
587 	int error, offset;
588 
589 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
590 
591 	/*
592 	 * Convert our time representation into something the DSXXXX
593 	 * can understand.
594 	 */
595 	bcd[DSXXXX_SECONDS] = bintobcd(dt->dt_sec);
596 	bcd[DSXXXX_MINUTES] = bintobcd(dt->dt_min);
597 	bcd[DSXXXX_HOURS] = bintobcd(dt->dt_hour); /* DSXXXX_HOURS_12HRS_MODE=0 */
598 	bcd[DSXXXX_DATE] = bintobcd(dt->dt_day);
599 	bcd[DSXXXX_DAY] = bintobcd(dt->dt_wday);
600 	bcd[DSXXXX_MONTH] = bintobcd(dt->dt_mon);
601 
602 	if (sc->sc_model.dm_flags & DSRTC_FLAG_YEAR_START_2K) {
603 		offset = 2000;
604 	} else {
605 		offset = POSIX_BASE_YEAR;
606 	}
607 
608 	bcd[DSXXXX_YEAR] = bintobcd((dt->dt_year - offset) % 100);
609 	if (dt->dt_year - offset >= 100)
610 		bcd[DSXXXX_MONTH] |= DSXXXX_MONTH_CENTURY;
611 
612 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
613 		aprint_error_dev(sc->sc_dev,
614 		    "%s: failed to acquire I2C bus: %d\n",
615 		    __func__, error);
616 		return 0;
617 	}
618 
619 	/* Stop the clock */
620 	cmdbuf[0] = dm->dm_ch_reg;
621 
622 	if ((error = iic_exec(sc->sc_tag, I2C_OP_READ, sc->sc_address,
623 	    cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
624 		iic_release_bus(sc->sc_tag, 0);
625 		aprint_error_dev(sc->sc_dev,
626 		    "%s: failed to read Hold Clock: %d\n",
627 		    __func__, error);
628 		return 0;
629 	}
630 
631 	if (sc->sc_model.dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
632 		cmdbuf[1] &= ~dm->dm_ch_value;
633 	else
634 		cmdbuf[1] |= dm->dm_ch_value;
635 
636 	if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address,
637 	    cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
638 		iic_release_bus(sc->sc_tag, 0);
639 		aprint_error_dev(sc->sc_dev,
640 		    "%s: failed to write Hold Clock: %d\n",
641 		    __func__, error);
642 		return 0;
643 	}
644 
645 	/*
646 	 * Write registers in reverse order. The last write (to the Seconds
647 	 * register) will undo the Clock Hold, above.
648 	 */
649 	uint8_t op = I2C_OP_WRITE;
650 	for (signed int i = dm->dm_rtc_size - 1; i >= 0; i--) {
651 		cmdbuf[0] = dm->dm_rtc_start + i;
652 		if ((dm->dm_flags & DSRTC_FLAG_VBATEN) &&
653 				dm->dm_rtc_start + i == dm->dm_vbaten_reg)
654 			bcd[i] |= dm->dm_vbaten_value;
655 		if (dm->dm_rtc_start + i == dm->dm_ch_reg) {
656 			op = I2C_OP_WRITE_WITH_STOP;
657 			if (dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
658 				bcd[i] |= dm->dm_ch_value;
659 		}
660 		if ((error = iic_exec(sc->sc_tag, op, sc->sc_address,
661 		    cmdbuf, 1, &bcd[i], 1, 0)) != 0) {
662 			iic_release_bus(sc->sc_tag, 0);
663 			aprint_error_dev(sc->sc_dev,
664 			    "%s: failed to write rtc at 0x%x: %d\n",
665 			    __func__, i, error);
666 			/* XXX: Clock Hold is likely still asserted! */
667 			return 0;
668 		}
669 	}
670 	/*
671 	 * If the clock hold register isn't the same register as seconds,
672 	 * we need to reeanble the clock.
673 	 */
674 	if (op != I2C_OP_WRITE_WITH_STOP) {
675 		cmdbuf[0] = dm->dm_ch_reg;
676 		if (dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
677 			cmdbuf[1] |= dm->dm_ch_value;
678 		else
679 			cmdbuf[1] &= ~dm->dm_ch_value;
680 
681 		if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
682 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
683 			iic_release_bus(sc->sc_tag, 0);
684 			aprint_error_dev(sc->sc_dev,
685 			    "%s: failed to Hold Clock: %d\n",
686 			    __func__, error);
687 			return 0;
688 		}
689 	}
690 
691 	iic_release_bus(sc->sc_tag, 0);
692 
693 	return 1;
694 }
695 
696 static int
697 dsrtc_gettime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
698 {
699 	struct dsrtc_softc *sc = ch->cookie;
700 	struct timeval check;
701 	int retries;
702 
703 	memset(tv, 0, sizeof(*tv));
704 	memset(&check, 0, sizeof(check));
705 
706 	/*
707 	 * Since we don't support Burst Read, we have to read the clock twice
708 	 * until we get two consecutive identical results.
709 	 */
710 	retries = 5;
711 	do {
712 		dsrtc_clock_read_timeval(sc, &tv->tv_sec);
713 		dsrtc_clock_read_timeval(sc, &check.tv_sec);
714 	} while (memcmp(tv, &check, sizeof(check)) != 0 && --retries);
715 
716 	return 0;
717 }
718 
719 static int
720 dsrtc_settime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
721 {
722 	struct dsrtc_softc *sc = ch->cookie;
723 
724 	if (dsrtc_clock_write_timeval(sc, tv->tv_sec) == 0)
725 		return -1;
726 
727 	return 0;
728 }
729 
730 /*
731  * The RTC probably has a nice Clock Burst Read/Write command, but we can't use
732  * it, since some I2C controllers don't support anything other than single-byte
733  * transfers.
734  */
735 static int
736 dsrtc_clock_read_timeval(struct dsrtc_softc *sc, time_t *tp)
737 {
738 	const struct dsrtc_model * const dm = &sc->sc_model;
739 	uint8_t buf[4];
740 	int error;
741 
742 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
743 		aprint_error_dev(sc->sc_dev,
744 		    "%s: failed to acquire I2C bus: %d\n",
745 		    __func__, error);
746 		return 0;
747 	}
748 
749 	/* read all registers: */
750 	uint8_t reg = dm->dm_rtc_start;
751 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
752 	     &reg, 1, buf, 4, 0);
753 
754 	/* Done with I2C */
755 	iic_release_bus(sc->sc_tag, 0);
756 
757 	if (error != 0) {
758 		aprint_error_dev(sc->sc_dev,
759 		    "%s: failed to read rtc at 0x%x: %d\n",
760 		    __func__, reg, error);
761 		return 0;
762 	}
763 
764 	uint32_t v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
765 	*tp = v;
766 
767 	aprint_debug_dev(sc->sc_dev, "%s: cntr=0x%08"PRIx32"\n",
768 	    __func__, v);
769 
770 	return 1;
771 }
772 
773 static int
774 dsrtc_clock_write_timeval(struct dsrtc_softc *sc, time_t t)
775 {
776 	const struct dsrtc_model * const dm = &sc->sc_model;
777 	size_t buflen = dm->dm_rtc_size + 2;
778 	/* XXX: the biggest dm_rtc_size we have now is 7, so we should be ok */
779 	uint8_t buf[16];
780 	int error;
781 
782 	KASSERT((dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD) == 0);
783 	KASSERT(dm->dm_ch_reg == dm->dm_rtc_start + 4);
784 
785 	buf[0] = dm->dm_rtc_start;
786 	buf[1] = (t >> 0) & 0xff;
787 	buf[2] = (t >> 8) & 0xff;
788 	buf[3] = (t >> 16) & 0xff;
789 	buf[4] = (t >> 24) & 0xff;
790 	buf[5] = 0;
791 
792 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
793 		aprint_error_dev(sc->sc_dev,
794 		    "%s: failed to acquire I2C bus: %d\n",
795 		    __func__, error);
796 		return 0;
797 	}
798 
799 	error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
800 	    &buf, buflen, NULL, 0, 0);
801 
802 	/* Done with I2C */
803 	iic_release_bus(sc->sc_tag, 0);
804 
805 	/* send data */
806 	if (error != 0) {
807 		aprint_error_dev(sc->sc_dev,
808 		    "%s: failed to set time: %d\n",
809 		    __func__, error);
810 		return 0;
811 	}
812 
813 	return 1;
814 }
815 
816 static int
817 dsrtc_read_temp(struct dsrtc_softc *sc, uint32_t *temp)
818 {
819 	int error, tc;
820 	uint8_t reg = DS3232_TEMP_MSB;
821 	uint8_t buf[2];
822 
823 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) == 0)
824 		return ENOTSUP;
825 
826 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0) {
827 		aprint_error_dev(sc->sc_dev,
828 		    "%s: failed to acquire I2C bus: %d\n",
829 		    __func__, error);
830 		return 0;
831 	}
832 
833 	/* read temperature registers: */
834 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
835 	     &reg, 1, buf, 2, 0);
836 
837 	/* Done with I2C */
838 	iic_release_bus(sc->sc_tag, 0);
839 
840 	if (error != 0) {
841 		aprint_error_dev(sc->sc_dev,
842 		    "%s: failed to read temperature: %d\n",
843 		    __func__, error);
844 		return 0;
845 	}
846 
847 	/* convert to microkelvin */
848 	tc = buf[0] * 1000000 + (buf[1] >> 6) * 250000;
849 	*temp = tc + 273150000;
850 	return 1;
851 }
852 
853 static void
854 dsrtc_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
855 {
856 	struct dsrtc_softc *sc = sme->sme_cookie;
857 	uint32_t temp = 0;	/* XXX gcc */
858 
859 	if (dsrtc_read_temp(sc, &temp) == 0) {
860 		edata->state = ENVSYS_SINVALID;
861 		return;
862 	}
863 
864 	edata->value_cur = temp;
865 
866 	edata->state = ENVSYS_SVALID;
867 }
868