xref: /netbsd-src/sys/dev/i2c/ds1307.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*	$NetBSD: ds1307.c,v 1.29 2018/06/26 06:03:57 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 1.29 2018/06/26 06:03:57 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 
58 struct dsrtc_model {
59 	const i2c_addr_t *dm_valid_addrs;
60 	uint16_t dm_model;
61 	uint8_t dm_ch_reg;
62 	uint8_t dm_ch_value;
63 	uint8_t dm_vbaten_reg;
64 	uint8_t dm_vbaten_value;
65 	uint8_t dm_rtc_start;
66 	uint8_t dm_rtc_size;
67 	uint8_t dm_nvram_start;
68 	uint8_t dm_nvram_size;
69 	uint8_t dm_flags;
70 #define	DSRTC_FLAG_CLOCK_HOLD		0x01
71 #define	DSRTC_FLAG_BCD			0x02
72 #define	DSRTC_FLAG_TEMP			0x04
73 #define DSRTC_FLAG_VBATEN		0x08
74 #define	DSRTC_FLAG_YEAR_START_2K	0x10
75 #define	DSRTC_FLAG_CLOCK_HOLD_REVERSED	0x20
76 };
77 
78 static const i2c_addr_t ds1307_valid_addrs[] = { DS1307_ADDR, 0 };
79 static const struct dsrtc_model ds1307_model = {
80 	.dm_valid_addrs = ds1307_valid_addrs,
81 	.dm_model = 1307,
82 	.dm_ch_reg = DSXXXX_SECONDS,
83 	.dm_ch_value = DS1307_SECONDS_CH,
84 	.dm_rtc_start = DS1307_RTC_START,
85 	.dm_rtc_size = DS1307_RTC_SIZE,
86 	.dm_nvram_start = DS1307_NVRAM_START,
87 	.dm_nvram_size = DS1307_NVRAM_SIZE,
88 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_CLOCK_HOLD,
89 };
90 
91 static const struct dsrtc_model ds1339_model = {
92 	.dm_valid_addrs = ds1307_valid_addrs,
93 	.dm_model = 1339,
94 	.dm_rtc_start = DS1339_RTC_START,
95 	.dm_rtc_size = DS1339_RTC_SIZE,
96 	.dm_flags = DSRTC_FLAG_BCD,
97 };
98 
99 static const struct dsrtc_model ds1340_model = {
100 	.dm_valid_addrs = ds1307_valid_addrs,
101 	.dm_model = 1340,
102 	.dm_ch_reg = DSXXXX_SECONDS,
103 	.dm_ch_value = DS1340_SECONDS_EOSC,
104 	.dm_rtc_start = DS1340_RTC_START,
105 	.dm_rtc_size = DS1340_RTC_SIZE,
106 	.dm_flags = DSRTC_FLAG_BCD,
107 };
108 
109 static const struct dsrtc_model ds1672_model = {
110 	.dm_valid_addrs = ds1307_valid_addrs,
111 	.dm_model = 1672,
112 	.dm_rtc_start = DS1672_RTC_START,
113 	.dm_rtc_size = DS1672_RTC_SIZE,
114 	.dm_ch_reg = DS1672_CONTROL,
115 	.dm_ch_value = DS1672_CONTROL_CH,
116 	.dm_flags = 0,
117 };
118 
119 static const struct dsrtc_model ds3231_model = {
120 	.dm_valid_addrs = ds1307_valid_addrs,
121 	.dm_model = 3231,
122 	.dm_rtc_start = DS3232_RTC_START,
123 	.dm_rtc_size = DS3232_RTC_SIZE,
124 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_TEMP,
125 };
126 
127 static const struct dsrtc_model ds3232_model = {
128 	.dm_valid_addrs = ds1307_valid_addrs,
129 	.dm_model = 3232,
130 	.dm_rtc_start = DS3232_RTC_START,
131 	.dm_rtc_size = DS3232_RTC_SIZE,
132 	.dm_nvram_start = DS3232_NVRAM_START,
133 	.dm_nvram_size = DS3232_NVRAM_SIZE,
134 	/*
135 	 * XXX
136 	 * the DS3232 likely has the temperature sensor too but I can't
137 	 * easily verify or test that right now
138 	 */
139 	.dm_flags = DSRTC_FLAG_BCD,
140 };
141 
142 static const i2c_addr_t mcp7940_valid_addrs[] = { MCP7940_ADDR, 0 };
143 static const struct dsrtc_model mcp7940_model = {
144 	.dm_valid_addrs = mcp7940_valid_addrs,
145 	.dm_model = 7940,
146 	.dm_rtc_start = DS1307_RTC_START,
147 	.dm_rtc_size = DS1307_RTC_SIZE,
148 	.dm_ch_reg = DSXXXX_SECONDS,
149 	.dm_ch_value = DS1307_SECONDS_CH,
150 	.dm_vbaten_reg = DSXXXX_DAY,
151 	.dm_vbaten_value = MCP7940_TOD_DAY_VBATEN,
152 	.dm_nvram_start = MCP7940_NVRAM_START,
153 	.dm_nvram_size = MCP7940_NVRAM_SIZE,
154 	.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_CLOCK_HOLD |
155 		DSRTC_FLAG_VBATEN | DSRTC_FLAG_CLOCK_HOLD_REVERSED,
156 };
157 
158 static const struct device_compatible_entry compat_data[] = {
159 	{ "dallas,ds1307",		(uintptr_t)&ds1307_model },
160 	{ "maxim,ds1307",		(uintptr_t)&ds1307_model },
161 
162 	{ "dallas,ds1339",		(uintptr_t)&ds1339_model },
163 	{ "maxim,ds1339",		(uintptr_t)&ds1339_model },
164 
165 	{ "dallas,ds1340",		(uintptr_t)&ds1340_model },
166 	{ "maxim,ds1340",		(uintptr_t)&ds1340_model },
167 
168 	{ "dallas,ds1672",		(uintptr_t)&ds1672_model },
169 	{ "maxim,ds1672",		(uintptr_t)&ds1672_model },
170 
171 	{ "dallas,ds3231",		(uintptr_t)&ds3231_model },
172 	{ "maxim,ds3231",		(uintptr_t)&ds3231_model },
173 
174 	{ "dallas,ds3232",		(uintptr_t)&ds3232_model },
175 	{ "maxim,ds3232",		(uintptr_t)&ds3232_model },
176 
177 	{ "microchip,mcp7940",		(uintptr_t)&mcp7940_model },
178 
179 	{ NULL,				0 }
180 };
181 
182 struct dsrtc_softc {
183 	device_t sc_dev;
184 	i2c_tag_t sc_tag;
185 	uint8_t sc_address;
186 	bool sc_open;
187 	struct dsrtc_model sc_model;
188 	struct todr_chip_handle sc_todr;
189 	struct sysmon_envsys *sc_sme;
190 	envsys_data_t sc_sensor;
191 };
192 
193 static void	dsrtc_attach(device_t, device_t, void *);
194 static int	dsrtc_match(device_t, cfdata_t, void *);
195 
196 CFATTACH_DECL_NEW(dsrtc, sizeof(struct dsrtc_softc),
197     dsrtc_match, dsrtc_attach, NULL, NULL);
198 
199 dev_type_open(dsrtc_open);
200 dev_type_close(dsrtc_close);
201 dev_type_read(dsrtc_read);
202 dev_type_write(dsrtc_write);
203 
204 const struct cdevsw dsrtc_cdevsw = {
205 	.d_open = dsrtc_open,
206 	.d_close = dsrtc_close,
207 	.d_read = dsrtc_read,
208 	.d_write = dsrtc_write,
209 	.d_ioctl = noioctl,
210 	.d_stop = nostop,
211 	.d_tty = notty,
212 	.d_poll = nopoll,
213 	.d_mmap = nommap,
214 	.d_kqfilter = nokqfilter,
215 	.d_discard = nodiscard,
216 	.d_flag = D_OTHER
217 };
218 
219 static int dsrtc_gettime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
220 static int dsrtc_settime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
221 static int dsrtc_clock_read_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
222 static int dsrtc_clock_write_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
223 
224 static int dsrtc_gettime_timeval(struct todr_chip_handle *, struct timeval *);
225 static int dsrtc_settime_timeval(struct todr_chip_handle *, struct timeval *);
226 static int dsrtc_clock_read_timeval(struct dsrtc_softc *, time_t *);
227 static int dsrtc_clock_write_timeval(struct dsrtc_softc *, time_t);
228 
229 static int dsrtc_read_temp(struct dsrtc_softc *, uint32_t *);
230 static void dsrtc_refresh(struct sysmon_envsys *, envsys_data_t *);
231 
232 static const struct dsrtc_model *
233 dsrtc_model_by_number(u_int model)
234 {
235 	const struct device_compatible_entry *dce;
236 	const struct dsrtc_model *dm;
237 
238 	/* no model given, assume it's a DS1307 */
239 	if (model == 0)
240 		return &ds1307_model;
241 
242 	for (dce = compat_data; dce->compat != NULL; dce++) {
243 		dm = (void *)dce->data;
244 		if (dm->dm_model == model)
245 			return dm;
246 	}
247 	return NULL;
248 }
249 
250 static const struct dsrtc_model *
251 dsrtc_model_by_compat(const struct i2c_attach_args *ia)
252 {
253 	const struct dsrtc_model *dm = NULL;
254 	const struct device_compatible_entry *dce;
255 
256 	if (iic_compatible_match(ia, compat_data, &dce))
257 		dm = (void *)dce->data;
258 
259 	return dm;
260 }
261 
262 static bool
263 dsrtc_is_valid_addr_for_model(const struct dsrtc_model *dm, i2c_addr_t addr)
264 {
265 
266 	for (int i = 0; dm->dm_valid_addrs[i] != 0; i++) {
267 		if (addr == dm->dm_valid_addrs[i])
268 			return true;
269 	}
270 	return false;
271 }
272 
273 static int
274 dsrtc_match(device_t parent, cfdata_t cf, void *arg)
275 {
276 	struct i2c_attach_args *ia = arg;
277 	const struct dsrtc_model *dm;
278 	int match_result;
279 
280 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
281 		return match_result;
282 
283 	dm = dsrtc_model_by_number(cf->cf_flags & 0xffff);
284 	if (dm == NULL)
285 		return 0;
286 
287 	if (dsrtc_is_valid_addr_for_model(dm, ia->ia_addr))
288 		return I2C_MATCH_ADDRESS_ONLY;
289 
290 	return 0;
291 }
292 
293 static void
294 dsrtc_attach(device_t parent, device_t self, void *arg)
295 {
296 	struct dsrtc_softc *sc = device_private(self);
297 	struct i2c_attach_args *ia = arg;
298 	const struct dsrtc_model *dm;
299 
300 	if ((dm = dsrtc_model_by_compat(ia)) == NULL)
301 		dm = dsrtc_model_by_number(device_cfdata(self)->cf_flags);
302 
303 	if (dm == NULL) {
304 		aprint_error(": unable to determine model!\n");
305 		return;
306 	}
307 
308 	aprint_naive(": Real-time Clock%s\n",
309 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
310 	aprint_normal(": DS%u Real-time Clock%s\n", dm->dm_model,
311 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
312 
313 	sc->sc_tag = ia->ia_tag;
314 	sc->sc_address = ia->ia_addr;
315 	sc->sc_model = *dm;
316 	sc->sc_dev = self;
317 	sc->sc_open = 0;
318 	sc->sc_todr.cookie = sc;
319 	if (dm->dm_flags & DSRTC_FLAG_BCD) {
320 		sc->sc_todr.todr_gettime_ymdhms = dsrtc_gettime_ymdhms;
321 		sc->sc_todr.todr_settime_ymdhms = dsrtc_settime_ymdhms;
322 	} else {
323 		sc->sc_todr.todr_gettime = dsrtc_gettime_timeval;
324 		sc->sc_todr.todr_settime = dsrtc_settime_timeval;
325 	}
326 	sc->sc_todr.todr_setwen = NULL;
327 
328 	todr_attach(&sc->sc_todr);
329 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) != 0) {
330 		int error;
331 
332 		sc->sc_sme = sysmon_envsys_create();
333 		sc->sc_sme->sme_name = device_xname(self);
334 		sc->sc_sme->sme_cookie = sc;
335 		sc->sc_sme->sme_refresh = dsrtc_refresh;
336 
337 		sc->sc_sensor.units =  ENVSYS_STEMP;
338 		sc->sc_sensor.state = ENVSYS_SINVALID;
339 		sc->sc_sensor.flags = 0;
340 		(void)strlcpy(sc->sc_sensor.desc, "temperature",
341 		    sizeof(sc->sc_sensor.desc));
342 
343 		if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
344 			aprint_error_dev(self, "unable to attach sensor\n");
345 			goto bad;
346 		}
347 
348 		error = sysmon_envsys_register(sc->sc_sme);
349 		if (error) {
350 			aprint_error_dev(self,
351 			    "error %d registering with sysmon\n", error);
352 			goto bad;
353 		}
354 	}
355 	return;
356 bad:
357 	sysmon_envsys_destroy(sc->sc_sme);
358 }
359 
360 /*ARGSUSED*/
361 int
362 dsrtc_open(dev_t dev, int flag, int fmt, struct lwp *l)
363 {
364 	struct dsrtc_softc *sc;
365 
366 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
367 		return ENXIO;
368 
369 	/* XXX: Locking */
370 	if (sc->sc_open)
371 		return EBUSY;
372 
373 	sc->sc_open = true;
374 	return 0;
375 }
376 
377 /*ARGSUSED*/
378 int
379 dsrtc_close(dev_t dev, int flag, int fmt, struct lwp *l)
380 {
381 	struct dsrtc_softc *sc;
382 
383 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
384 		return ENXIO;
385 
386 	sc->sc_open = false;
387 	return 0;
388 }
389 
390 /*ARGSUSED*/
391 int
392 dsrtc_read(dev_t dev, struct uio *uio, int flags)
393 {
394 	struct dsrtc_softc *sc;
395 	int error;
396 
397 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
398 		return ENXIO;
399 
400 	const struct dsrtc_model * const dm = &sc->sc_model;
401 	if (uio->uio_offset >= dm->dm_nvram_size)
402 		return EINVAL;
403 
404 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
405 		return error;
406 
407 	KASSERT(uio->uio_offset >= 0);
408 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
409 		uint8_t ch, cmd;
410 		const u_int a = uio->uio_offset;
411 		cmd = a + dm->dm_nvram_start;
412 		if ((error = iic_exec(sc->sc_tag,
413 		    uio->uio_resid > 1 ? I2C_OP_READ : I2C_OP_READ_WITH_STOP,
414 		    sc->sc_address, &cmd, 1, &ch, 1, 0)) != 0) {
415 			iic_release_bus(sc->sc_tag, 0);
416 			aprint_error_dev(sc->sc_dev,
417 			    "%s: read failed at 0x%x: %d\n",
418 			    __func__, a, error);
419 			return error;
420 		}
421 		if ((error = uiomove(&ch, 1, uio)) != 0) {
422 			iic_release_bus(sc->sc_tag, 0);
423 			return error;
424 		}
425 	}
426 
427 	iic_release_bus(sc->sc_tag, 0);
428 
429 	return 0;
430 }
431 
432 /*ARGSUSED*/
433 int
434 dsrtc_write(dev_t dev, struct uio *uio, int flags)
435 {
436 	struct dsrtc_softc *sc;
437 	int error;
438 
439 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
440 		return ENXIO;
441 
442 	const struct dsrtc_model * const dm = &sc->sc_model;
443 	if (uio->uio_offset >= dm->dm_nvram_size)
444 		return EINVAL;
445 
446 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
447 		return error;
448 
449 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
450 		uint8_t cmdbuf[2];
451 		const u_int a = (int)uio->uio_offset;
452 		cmdbuf[0] = a + dm->dm_nvram_start;
453 		if ((error = uiomove(&cmdbuf[1], 1, uio)) != 0)
454 			break;
455 
456 		if ((error = iic_exec(sc->sc_tag,
457 		    uio->uio_resid ? I2C_OP_WRITE : I2C_OP_WRITE_WITH_STOP,
458 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
459 			aprint_error_dev(sc->sc_dev,
460 			    "%s: write failed at 0x%x: %d\n",
461 			    __func__, a, error);
462 			break;
463 		}
464 	}
465 
466 	iic_release_bus(sc->sc_tag, 0);
467 
468 	return error;
469 }
470 
471 static int
472 dsrtc_gettime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
473 {
474 	struct dsrtc_softc *sc = ch->cookie;
475 	struct clock_ymdhms check;
476 	int retries;
477 
478 	memset(dt, 0, sizeof(*dt));
479 	memset(&check, 0, sizeof(check));
480 
481 	/*
482 	 * Since we don't support Burst Read, we have to read the clock twice
483 	 * until we get two consecutive identical results.
484 	 */
485 	retries = 5;
486 	do {
487 		dsrtc_clock_read_ymdhms(sc, dt);
488 		dsrtc_clock_read_ymdhms(sc, &check);
489 	} while (memcmp(dt, &check, sizeof(check)) != 0 && --retries);
490 
491 	return 0;
492 }
493 
494 static int
495 dsrtc_settime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
496 {
497 	struct dsrtc_softc *sc = ch->cookie;
498 
499 	if (dsrtc_clock_write_ymdhms(sc, dt) == 0)
500 		return -1;
501 
502 	return 0;
503 }
504 
505 static int
506 dsrtc_clock_read_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
507 {
508 	struct dsrtc_model * const dm = &sc->sc_model;
509 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[1];
510 	int error;
511 
512 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
513 
514 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
515 		aprint_error_dev(sc->sc_dev,
516 		    "%s: failed to acquire I2C bus: %d\n",
517 		    __func__, error);
518 		return 0;
519 	}
520 
521 	/* Read each RTC register in order. */
522 	for (u_int i = 0; !error && i < dm->dm_rtc_size; i++) {
523 		cmdbuf[0] = dm->dm_rtc_start + i;
524 
525 		error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
526 		    sc->sc_address, cmdbuf, 1, &bcd[i], 1, I2C_F_POLL);
527 	}
528 
529 	/* Done with I2C */
530 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
531 
532 	if (error != 0) {
533 		aprint_error_dev(sc->sc_dev,
534 		    "%s: failed to read rtc at 0x%x: %d\n",
535 		    __func__, cmdbuf[0], error);
536 		return 0;
537 	}
538 
539 	/*
540 	 * Convert the RTC's register values into something useable
541 	 */
542 	dt->dt_sec = bcdtobin(bcd[DSXXXX_SECONDS] & DSXXXX_SECONDS_MASK);
543 	dt->dt_min = bcdtobin(bcd[DSXXXX_MINUTES] & DSXXXX_MINUTES_MASK);
544 
545 	if ((bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_MODE) != 0) {
546 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
547 		    DSXXXX_HOURS_12MASK) % 12; /* 12AM -> 0, 12PM -> 12 */
548 		if (bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_PM)
549 			dt->dt_hour += 12;
550 	} else
551 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
552 		    DSXXXX_HOURS_24MASK);
553 
554 	dt->dt_day = bcdtobin(bcd[DSXXXX_DATE] & DSXXXX_DATE_MASK);
555 	dt->dt_mon = bcdtobin(bcd[DSXXXX_MONTH] & DSXXXX_MONTH_MASK);
556 
557 	/* XXX: Should be an MD way to specify EPOCH used by BIOS/Firmware */
558 	if (sc->sc_model.dm_flags & DSRTC_FLAG_YEAR_START_2K)
559 		dt->dt_year = bcdtobin(bcd[DSXXXX_YEAR]) + 2000;
560 	else {
561 		dt->dt_year = bcdtobin(bcd[DSXXXX_YEAR]) + POSIX_BASE_YEAR;
562 		if (bcd[DSXXXX_MONTH] & DSXXXX_MONTH_CENTURY)
563 			dt->dt_year += 100;
564 	}
565 
566 	return 1;
567 }
568 
569 static int
570 dsrtc_clock_write_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
571 {
572 	struct dsrtc_model * const dm = &sc->sc_model;
573 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[2];
574 	int error;
575 
576 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
577 
578 	/*
579 	 * Convert our time representation into something the DSXXXX
580 	 * can understand.
581 	 */
582 	bcd[DSXXXX_SECONDS] = bintobcd(dt->dt_sec);
583 	bcd[DSXXXX_MINUTES] = bintobcd(dt->dt_min);
584 	bcd[DSXXXX_HOURS] = bintobcd(dt->dt_hour); /* DSXXXX_HOURS_12HRS_MODE=0 */
585 	bcd[DSXXXX_DATE] = bintobcd(dt->dt_day);
586 	bcd[DSXXXX_DAY] = bintobcd(dt->dt_wday);
587 	bcd[DSXXXX_MONTH] = bintobcd(dt->dt_mon);
588 	bcd[DSXXXX_YEAR] = bintobcd((dt->dt_year - POSIX_BASE_YEAR) % 100);
589 	if (dt->dt_year - POSIX_BASE_YEAR >= 100)
590 		bcd[DSXXXX_MONTH] |= DSXXXX_MONTH_CENTURY;
591 
592 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
593 		aprint_error_dev(sc->sc_dev,
594 		    "%s: failed to acquire I2C bus: %d\n",
595 		    __func__, error);
596 		return 0;
597 	}
598 
599 	/* Stop the clock */
600 	cmdbuf[0] = dm->dm_ch_reg;
601 
602 	if ((error = iic_exec(sc->sc_tag, I2C_OP_READ, sc->sc_address,
603 	    cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL)) != 0) {
604 		iic_release_bus(sc->sc_tag, I2C_F_POLL);
605 		aprint_error_dev(sc->sc_dev,
606 		    "%s: failed to read Hold Clock: %d\n",
607 		    __func__, error);
608 		return 0;
609 	}
610 
611 	if (sc->sc_model.dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
612 		cmdbuf[1] &= ~dm->dm_ch_value;
613 	else
614 		cmdbuf[1] |= dm->dm_ch_value;
615 
616 	if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address,
617 	    cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL)) != 0) {
618 		iic_release_bus(sc->sc_tag, I2C_F_POLL);
619 		aprint_error_dev(sc->sc_dev,
620 		    "%s: failed to write Hold Clock: %d\n",
621 		    __func__, error);
622 		return 0;
623 	}
624 
625 	/*
626 	 * Write registers in reverse order. The last write (to the Seconds
627 	 * register) will undo the Clock Hold, above.
628 	 */
629 	uint8_t op = I2C_OP_WRITE;
630 	for (signed int i = dm->dm_rtc_size - 1; i >= 0; i--) {
631 		cmdbuf[0] = dm->dm_rtc_start + i;
632 		if ((dm->dm_flags & DSRTC_FLAG_VBATEN) &&
633 				dm->dm_rtc_start + i == dm->dm_vbaten_reg)
634 			bcd[i] |= dm->dm_vbaten_value;
635 		if (dm->dm_rtc_start + i == dm->dm_ch_reg) {
636 			op = I2C_OP_WRITE_WITH_STOP;
637 			if (dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
638 				bcd[i] |= dm->dm_ch_value;
639 		}
640 		if ((error = iic_exec(sc->sc_tag, op, sc->sc_address,
641 		    cmdbuf, 1, &bcd[i], 1, I2C_F_POLL)) != 0) {
642 			iic_release_bus(sc->sc_tag, I2C_F_POLL);
643 			aprint_error_dev(sc->sc_dev,
644 			    "%s: failed to write rtc at 0x%x: %d\n",
645 			    __func__, i, error);
646 			/* XXX: Clock Hold is likely still asserted! */
647 			return 0;
648 		}
649 	}
650 	/*
651 	 * If the clock hold register isn't the same register as seconds,
652 	 * we need to reeanble the clock.
653 	 */
654 	if (op != I2C_OP_WRITE_WITH_STOP) {
655 		cmdbuf[0] = dm->dm_ch_reg;
656 		if (dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD_REVERSED)
657 			cmdbuf[1] |= dm->dm_ch_value;
658 		else
659 			cmdbuf[1] &= ~dm->dm_ch_value;
660 
661 		if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
662 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1,
663 		    I2C_F_POLL)) != 0) {
664 			iic_release_bus(sc->sc_tag, I2C_F_POLL);
665 			aprint_error_dev(sc->sc_dev,
666 			    "%s: failed to Hold Clock: %d\n",
667 			    __func__, error);
668 			return 0;
669 		}
670 	}
671 
672 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
673 
674 	return 1;
675 }
676 
677 static int
678 dsrtc_gettime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
679 {
680 	struct dsrtc_softc *sc = ch->cookie;
681 	struct timeval check;
682 	int retries;
683 
684 	memset(tv, 0, sizeof(*tv));
685 	memset(&check, 0, sizeof(check));
686 
687 	/*
688 	 * Since we don't support Burst Read, we have to read the clock twice
689 	 * until we get two consecutive identical results.
690 	 */
691 	retries = 5;
692 	do {
693 		dsrtc_clock_read_timeval(sc, &tv->tv_sec);
694 		dsrtc_clock_read_timeval(sc, &check.tv_sec);
695 	} while (memcmp(tv, &check, sizeof(check)) != 0 && --retries);
696 
697 	return 0;
698 }
699 
700 static int
701 dsrtc_settime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
702 {
703 	struct dsrtc_softc *sc = ch->cookie;
704 
705 	if (dsrtc_clock_write_timeval(sc, tv->tv_sec) == 0)
706 		return -1;
707 
708 	return 0;
709 }
710 
711 /*
712  * The RTC probably has a nice Clock Burst Read/Write command, but we can't use
713  * it, since some I2C controllers don't support anything other than single-byte
714  * transfers.
715  */
716 static int
717 dsrtc_clock_read_timeval(struct dsrtc_softc *sc, time_t *tp)
718 {
719 	const struct dsrtc_model * const dm = &sc->sc_model;
720 	uint8_t buf[4];
721 	int error;
722 
723 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
724 		aprint_error_dev(sc->sc_dev,
725 		    "%s: failed to acquire I2C bus: %d\n",
726 		    __func__, error);
727 		return 0;
728 	}
729 
730 	/* read all registers: */
731 	uint8_t reg = dm->dm_rtc_start;
732 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
733 	     &reg, 1, buf, 4, I2C_F_POLL);
734 
735 	/* Done with I2C */
736 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
737 
738 	if (error != 0) {
739 		aprint_error_dev(sc->sc_dev,
740 		    "%s: failed to read rtc at 0x%x: %d\n",
741 		    __func__, reg, error);
742 		return 0;
743 	}
744 
745 	uint32_t v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
746 	*tp = v;
747 
748 	aprint_debug_dev(sc->sc_dev, "%s: cntr=0x%08"PRIx32"\n",
749 	    __func__, v);
750 
751 	return 1;
752 }
753 
754 static int
755 dsrtc_clock_write_timeval(struct dsrtc_softc *sc, time_t t)
756 {
757 	const struct dsrtc_model * const dm = &sc->sc_model;
758 	size_t buflen = dm->dm_rtc_size + 2;
759 	uint8_t buf[buflen];
760 	int error;
761 
762 	KASSERT((dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD) == 0);
763 	KASSERT(dm->dm_ch_reg == dm->dm_rtc_start + 4);
764 
765 	buf[0] = dm->dm_rtc_start;
766 	buf[1] = (t >> 0) & 0xff;
767 	buf[2] = (t >> 8) & 0xff;
768 	buf[3] = (t >> 16) & 0xff;
769 	buf[4] = (t >> 24) & 0xff;
770 	buf[5] = 0;
771 
772 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
773 		aprint_error_dev(sc->sc_dev,
774 		    "%s: failed to acquire I2C bus: %d\n",
775 		    __func__, error);
776 		return 0;
777 	}
778 
779 	error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
780 	    &buf, buflen, NULL, 0, I2C_F_POLL);
781 
782 	/* Done with I2C */
783 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
784 
785 	/* send data */
786 	if (error != 0) {
787 		aprint_error_dev(sc->sc_dev,
788 		    "%s: failed to set time: %d\n",
789 		    __func__, error);
790 		return 0;
791 	}
792 
793 	return 1;
794 }
795 
796 static int
797 dsrtc_read_temp(struct dsrtc_softc *sc, uint32_t *temp)
798 {
799 	int error, tc;
800 	uint8_t reg = DS3232_TEMP_MSB;
801 	uint8_t buf[2];
802 
803 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) == 0)
804 		return ENOTSUP;
805 
806 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
807 		aprint_error_dev(sc->sc_dev,
808 		    "%s: failed to acquire I2C bus: %d\n",
809 		    __func__, error);
810 		return 0;
811 	}
812 
813 	/* read temperature registers: */
814 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
815 	     &reg, 1, buf, 2, I2C_F_POLL);
816 
817 	/* Done with I2C */
818 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
819 
820 	if (error != 0) {
821 		aprint_error_dev(sc->sc_dev,
822 		    "%s: failed to read temperature: %d\n",
823 		    __func__, error);
824 		return 0;
825 	}
826 
827 	/* convert to microkelvin */
828 	tc = buf[0] * 1000000 + (buf[1] >> 6) * 250000;
829 	*temp = tc + 273150000;
830 	return 1;
831 }
832 
833 static void
834 dsrtc_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
835 {
836 	struct dsrtc_softc *sc = sme->sme_cookie;
837 	uint32_t temp = 0;	/* XXX gcc */
838 
839 	if (dsrtc_read_temp(sc, &temp) == 0) {
840 		edata->state = ENVSYS_SINVALID;
841 		return;
842 	}
843 
844 	edata->value_cur = temp;
845 
846 	edata->state = ENVSYS_SVALID;
847 }
848