xref: /netbsd-src/sys/dev/i2c/ds1307.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /*	$NetBSD: ds1307.c,v 1.21 2014/11/20 16:34:26 christos 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 1.21 2014/11/20 16:34:26 christos 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 struct dsrtc_model {
57 	uint16_t dm_model;
58 	uint8_t dm_ch_reg;
59 	uint8_t dm_ch_value;
60 	uint8_t dm_rtc_start;
61 	uint8_t dm_rtc_size;
62 	uint8_t dm_nvram_start;
63 	uint8_t dm_nvram_size;
64 	uint8_t dm_flags;
65 #define	DSRTC_FLAG_CLOCK_HOLD	1
66 #define	DSRTC_FLAG_BCD		2
67 #define	DSRTC_FLAG_TEMP		4
68 };
69 
70 static const struct dsrtc_model dsrtc_models[] = {
71 	{
72 		.dm_model = 1307,
73 		.dm_ch_reg = DSXXXX_SECONDS,
74 		.dm_ch_value = DS1307_SECONDS_CH,
75 		.dm_rtc_start = DS1307_RTC_START,
76 		.dm_rtc_size = DS1307_RTC_SIZE,
77 		.dm_nvram_start = DS1307_NVRAM_START,
78 		.dm_nvram_size = DS1307_NVRAM_SIZE,
79 		.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_CLOCK_HOLD,
80 	}, {
81 		.dm_model = 1339,
82 		.dm_rtc_start = DS1339_RTC_START,
83 		.dm_rtc_size = DS1339_RTC_SIZE,
84 		.dm_flags = DSRTC_FLAG_BCD,
85 	}, {
86 		.dm_model = 1672,
87 		.dm_rtc_start = DS1672_RTC_START,
88 		.dm_rtc_size = DS1672_RTC_SIZE,
89 		.dm_flags = 0,
90 	}, {
91 		.dm_model = 3231,
92 		.dm_rtc_start = DS3232_RTC_START,
93 		.dm_rtc_size = DS3232_RTC_SIZE,
94 		/*
95 		 * XXX
96 		 * the DS3232 likely has the temperature sensor too but I can't
97 		 * easily verify or test that right now
98 		 */
99 		.dm_flags = DSRTC_FLAG_BCD | DSRTC_FLAG_TEMP,
100 	}, {
101 		.dm_model = 3232,
102 		.dm_rtc_start = DS3232_RTC_START,
103 		.dm_rtc_size = DS3232_RTC_SIZE,
104 		.dm_nvram_start = DS3232_NVRAM_START,
105 		.dm_nvram_size = DS3232_NVRAM_SIZE,
106 		.dm_flags = DSRTC_FLAG_BCD,
107 	},
108 };
109 
110 struct dsrtc_softc {
111 	device_t sc_dev;
112 	i2c_tag_t sc_tag;
113 	uint8_t sc_address;
114 	bool sc_open;
115 	struct dsrtc_model sc_model;
116 	struct todr_chip_handle sc_todr;
117 	struct sysmon_envsys *sc_sme;
118 	envsys_data_t sc_sensor;
119 };
120 
121 static void	dsrtc_attach(device_t, device_t, void *);
122 static int	dsrtc_match(device_t, cfdata_t, void *);
123 
124 CFATTACH_DECL_NEW(dsrtc, sizeof(struct dsrtc_softc),
125     dsrtc_match, dsrtc_attach, NULL, NULL);
126 extern struct cfdriver dsrtc_cd;
127 
128 dev_type_open(dsrtc_open);
129 dev_type_close(dsrtc_close);
130 dev_type_read(dsrtc_read);
131 dev_type_write(dsrtc_write);
132 
133 const struct cdevsw dsrtc_cdevsw = {
134 	.d_open = dsrtc_open,
135 	.d_close = dsrtc_close,
136 	.d_read = dsrtc_read,
137 	.d_write = dsrtc_write,
138 	.d_ioctl = noioctl,
139 	.d_stop = nostop,
140 	.d_tty = notty,
141 	.d_poll = nopoll,
142 	.d_mmap = nommap,
143 	.d_kqfilter = nokqfilter,
144 	.d_discard = nodiscard,
145 	.d_flag = D_OTHER
146 };
147 
148 static int dsrtc_gettime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
149 static int dsrtc_settime_ymdhms(struct todr_chip_handle *, struct clock_ymdhms *);
150 static int dsrtc_clock_read_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
151 static int dsrtc_clock_write_ymdhms(struct dsrtc_softc *, struct clock_ymdhms *);
152 
153 static int dsrtc_gettime_timeval(struct todr_chip_handle *, struct timeval *);
154 static int dsrtc_settime_timeval(struct todr_chip_handle *, struct timeval *);
155 static int dsrtc_clock_read_timeval(struct dsrtc_softc *, time_t *);
156 static int dsrtc_clock_write_timeval(struct dsrtc_softc *, time_t);
157 
158 static int dsrtc_read_temp(struct dsrtc_softc *, uint32_t *);
159 static void dsrtc_refresh(struct sysmon_envsys *, envsys_data_t *);
160 
161 static const struct dsrtc_model *
162 dsrtc_model(u_int model)
163 {
164 	/* no model given, assume it's a DS1307 (the first one) */
165 	if (model == 0)
166 		return &dsrtc_models[0];
167 
168 	for (const struct dsrtc_model *dm = dsrtc_models;
169 	     dm < dsrtc_models + __arraycount(dsrtc_models); dm++) {
170 		if (dm->dm_model == model)
171 			return dm;
172 	}
173 	return NULL;
174 }
175 
176 static int
177 dsrtc_match(device_t parent, cfdata_t cf, void *arg)
178 {
179 	struct i2c_attach_args *ia = arg;
180 
181 	if (ia->ia_name) {
182 		/* direct config - check name */
183 		if (strcmp(ia->ia_name, "dsrtc") == 0)
184 			return 1;
185 	} else {
186 		/* indirect config - check typical address */
187 		if (ia->ia_addr == DS1307_ADDR)
188 			return dsrtc_model(cf->cf_flags & 0xffff) != NULL;
189 	}
190 	return 0;
191 }
192 
193 static void
194 dsrtc_attach(device_t parent, device_t self, void *arg)
195 {
196 	struct dsrtc_softc *sc = device_private(self);
197 	struct i2c_attach_args *ia = arg;
198 	const struct dsrtc_model * const dm =
199 	    dsrtc_model(device_cfdata(self)->cf_flags);
200 
201 	aprint_naive(": Real-time Clock%s\n",
202 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
203 	aprint_normal(": DS%u Real-time Clock%s\n", dm->dm_model,
204 	    dm->dm_nvram_size > 0 ? "/NVRAM" : "");
205 
206 	sc->sc_tag = ia->ia_tag;
207 	sc->sc_address = ia->ia_addr;
208 	sc->sc_model = *dm;
209 	sc->sc_dev = self;
210 	sc->sc_open = 0;
211 	sc->sc_todr.cookie = sc;
212 	if (dm->dm_flags & DSRTC_FLAG_BCD) {
213 		sc->sc_todr.todr_gettime_ymdhms = dsrtc_gettime_ymdhms;
214 		sc->sc_todr.todr_settime_ymdhms = dsrtc_settime_ymdhms;
215 	} else {
216 		sc->sc_todr.todr_gettime = dsrtc_gettime_timeval;
217 		sc->sc_todr.todr_settime = dsrtc_settime_timeval;
218 	}
219 	sc->sc_todr.todr_setwen = NULL;
220 
221 	todr_attach(&sc->sc_todr);
222 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) != 0) {
223 		int error;
224 
225 		sc->sc_sme = sysmon_envsys_create();
226 		sc->sc_sme->sme_name = device_xname(self);
227 		sc->sc_sme->sme_cookie = sc;
228 		sc->sc_sme->sme_refresh = dsrtc_refresh;
229 
230 		sc->sc_sensor.units =  ENVSYS_STEMP;
231 		sc->sc_sensor.state = ENVSYS_SINVALID;
232 		sc->sc_sensor.flags = 0;
233 		(void)strlcpy(sc->sc_sensor.desc, "temperature",
234 		    sizeof(sc->sc_sensor.desc));
235 
236 		if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
237 			aprint_error_dev(self, "unable to attach sensor\n");
238 			goto bad;
239 		}
240 
241 		error = sysmon_envsys_register(sc->sc_sme);
242 		if (error) {
243 			aprint_error_dev(self,
244 			    "error %d registering with sysmon\n", error);
245 			goto bad;
246 		}
247 	}
248 	return;
249 bad:
250 	sysmon_envsys_destroy(sc->sc_sme);
251 }
252 
253 /*ARGSUSED*/
254 int
255 dsrtc_open(dev_t dev, int flag, int fmt, struct lwp *l)
256 {
257 	struct dsrtc_softc *sc;
258 
259 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
260 		return ENXIO;
261 
262 	/* XXX: Locking */
263 	if (sc->sc_open)
264 		return EBUSY;
265 
266 	sc->sc_open = true;
267 	return 0;
268 }
269 
270 /*ARGSUSED*/
271 int
272 dsrtc_close(dev_t dev, int flag, int fmt, struct lwp *l)
273 {
274 	struct dsrtc_softc *sc;
275 
276 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
277 		return ENXIO;
278 
279 	sc->sc_open = false;
280 	return 0;
281 }
282 
283 /*ARGSUSED*/
284 int
285 dsrtc_read(dev_t dev, struct uio *uio, int flags)
286 {
287 	struct dsrtc_softc *sc;
288 	int error;
289 
290 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
291 		return ENXIO;
292 
293 	const struct dsrtc_model * const dm = &sc->sc_model;
294 	if (uio->uio_offset >= dm->dm_nvram_size)
295 		return EINVAL;
296 
297 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
298 		return error;
299 
300 	KASSERT(uio->uio_offset >= 0);
301 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
302 		uint8_t ch, cmd;
303 		const u_int a = uio->uio_offset;
304 		cmd = a + dm->dm_nvram_start;
305 		if ((error = iic_exec(sc->sc_tag,
306 		    uio->uio_resid > 1 ? I2C_OP_READ : I2C_OP_READ_WITH_STOP,
307 		    sc->sc_address, &cmd, 1, &ch, 1, 0)) != 0) {
308 			iic_release_bus(sc->sc_tag, 0);
309 			aprint_error_dev(sc->sc_dev,
310 			    "%s: read failed at 0x%x: %d\n",
311 			    __func__, a, error);
312 			return error;
313 		}
314 		if ((error = uiomove(&ch, 1, uio)) != 0) {
315 			iic_release_bus(sc->sc_tag, 0);
316 			return error;
317 		}
318 	}
319 
320 	iic_release_bus(sc->sc_tag, 0);
321 
322 	return 0;
323 }
324 
325 /*ARGSUSED*/
326 int
327 dsrtc_write(dev_t dev, struct uio *uio, int flags)
328 {
329 	struct dsrtc_softc *sc;
330 	int error;
331 
332 	if ((sc = device_lookup_private(&dsrtc_cd, minor(dev))) == NULL)
333 		return ENXIO;
334 
335 	const struct dsrtc_model * const dm = &sc->sc_model;
336 	if (uio->uio_offset >= dm->dm_nvram_size)
337 		return EINVAL;
338 
339 	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
340 		return error;
341 
342 	while (uio->uio_resid && uio->uio_offset < dm->dm_nvram_size) {
343 		uint8_t cmdbuf[2];
344 		const u_int a = (int)uio->uio_offset;
345 		cmdbuf[0] = a + dm->dm_nvram_start;
346 		if ((error = uiomove(&cmdbuf[1], 1, uio)) != 0)
347 			break;
348 
349 		if ((error = iic_exec(sc->sc_tag,
350 		    uio->uio_resid ? I2C_OP_WRITE : I2C_OP_WRITE_WITH_STOP,
351 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
352 			aprint_error_dev(sc->sc_dev,
353 			    "%s: write failed at 0x%x: %d\n",
354 			    __func__, a, error);
355 			break;
356 		}
357 	}
358 
359 	iic_release_bus(sc->sc_tag, 0);
360 
361 	return error;
362 }
363 
364 static int
365 dsrtc_gettime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
366 {
367 	struct dsrtc_softc *sc = ch->cookie;
368 	struct clock_ymdhms check;
369 	int retries;
370 
371 	memset(dt, 0, sizeof(*dt));
372 	memset(&check, 0, sizeof(check));
373 
374 	/*
375 	 * Since we don't support Burst Read, we have to read the clock twice
376 	 * until we get two consecutive identical results.
377 	 */
378 	retries = 5;
379 	do {
380 		dsrtc_clock_read_ymdhms(sc, dt);
381 		dsrtc_clock_read_ymdhms(sc, &check);
382 	} while (memcmp(dt, &check, sizeof(check)) != 0 && --retries);
383 
384 	return 0;
385 }
386 
387 static int
388 dsrtc_settime_ymdhms(struct todr_chip_handle *ch, struct clock_ymdhms *dt)
389 {
390 	struct dsrtc_softc *sc = ch->cookie;
391 
392 	if (dsrtc_clock_write_ymdhms(sc, dt) == 0)
393 		return -1;
394 
395 	return 0;
396 }
397 
398 static int
399 dsrtc_clock_read_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
400 {
401 	struct dsrtc_model * const dm = &sc->sc_model;
402 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[1];
403 	int error;
404 
405 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
406 
407 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
408 		aprint_error_dev(sc->sc_dev,
409 		    "%s: failed to acquire I2C bus: %d\n",
410 		    __func__, error);
411 		return 0;
412 	}
413 
414 	/* Read each RTC register in order. */
415 	for (u_int i = 0; !error && i < dm->dm_rtc_size; i++) {
416 		cmdbuf[0] = dm->dm_rtc_start + i;
417 
418 		error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
419 		    sc->sc_address, cmdbuf, 1, &bcd[i], 1, I2C_F_POLL);
420 	}
421 
422 	/* Done with I2C */
423 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
424 
425 	if (error != 0) {
426 		aprint_error_dev(sc->sc_dev,
427 		    "%s: failed to read rtc at 0x%x: %d\n",
428 		    __func__, cmdbuf[0], error);
429 		return 0;
430 	}
431 
432 	/*
433 	 * Convert the RTC's register values into something useable
434 	 */
435 	dt->dt_sec = bcdtobin(bcd[DSXXXX_SECONDS] & DSXXXX_SECONDS_MASK);
436 	dt->dt_min = bcdtobin(bcd[DSXXXX_MINUTES] & DSXXXX_MINUTES_MASK);
437 
438 	if ((bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_MODE) != 0) {
439 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
440 		    DSXXXX_HOURS_12MASK) % 12; /* 12AM -> 0, 12PM -> 12 */
441 		if (bcd[DSXXXX_HOURS] & DSXXXX_HOURS_12HRS_PM)
442 			dt->dt_hour += 12;
443 	} else
444 		dt->dt_hour = bcdtobin(bcd[DSXXXX_HOURS] &
445 		    DSXXXX_HOURS_24MASK);
446 
447 	dt->dt_day = bcdtobin(bcd[DSXXXX_DATE] & DSXXXX_DATE_MASK);
448 	dt->dt_mon = bcdtobin(bcd[DSXXXX_MONTH] & DSXXXX_MONTH_MASK);
449 
450 	/* XXX: Should be an MD way to specify EPOCH used by BIOS/Firmware */
451 	dt->dt_year = bcdtobin(bcd[DSXXXX_YEAR]) + POSIX_BASE_YEAR;
452 	if (bcd[DSXXXX_MONTH] & DSXXXX_MONTH_CENTURY)
453 		dt->dt_year += 100;
454 
455 	return 1;
456 }
457 
458 static int
459 dsrtc_clock_write_ymdhms(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
460 {
461 	struct dsrtc_model * const dm = &sc->sc_model;
462 	uint8_t bcd[DSXXXX_RTC_SIZE], cmdbuf[2];
463 	int error;
464 
465 	KASSERT(DSXXXX_RTC_SIZE >= dm->dm_rtc_size);
466 
467 	/*
468 	 * Convert our time representation into something the DSXXXX
469 	 * can understand.
470 	 */
471 	bcd[DSXXXX_SECONDS] = bintobcd(dt->dt_sec);
472 	bcd[DSXXXX_MINUTES] = bintobcd(dt->dt_min);
473 	bcd[DSXXXX_HOURS] = bintobcd(dt->dt_hour); /* DSXXXX_HOURS_12HRS_MODE=0 */
474 	bcd[DSXXXX_DATE] = bintobcd(dt->dt_day);
475 	bcd[DSXXXX_DAY] = bintobcd(dt->dt_wday);
476 	bcd[DSXXXX_MONTH] = bintobcd(dt->dt_mon);
477 	bcd[DSXXXX_YEAR] = bintobcd((dt->dt_year - POSIX_BASE_YEAR) % 100);
478 	if (dt->dt_year - POSIX_BASE_YEAR >= 100)
479 		bcd[DSXXXX_MONTH] |= DSXXXX_MONTH_CENTURY;
480 
481 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
482 		aprint_error_dev(sc->sc_dev,
483 		    "%s: failed to acquire I2C bus: %d\n",
484 		    __func__, error);
485 		return 0;
486 	}
487 
488 	/* Stop the clock */
489 	cmdbuf[0] = dm->dm_ch_reg;
490 
491 	if ((error = iic_exec(sc->sc_tag, I2C_OP_READ, sc->sc_address,
492 	    cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL)) != 0) {
493 		iic_release_bus(sc->sc_tag, I2C_F_POLL);
494 		aprint_error_dev(sc->sc_dev,
495 		    "%s: failed to read Hold Clock: %d\n",
496 		    __func__, error);
497 		return 0;
498 	}
499 
500 	cmdbuf[1] |= dm->dm_ch_value;
501 
502 	if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address,
503 	    cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL)) != 0) {
504 		iic_release_bus(sc->sc_tag, I2C_F_POLL);
505 		aprint_error_dev(sc->sc_dev,
506 		    "%s: failed to write Hold Clock: %d\n",
507 		    __func__, error);
508 		return 0;
509 	}
510 
511 	/*
512 	 * Write registers in reverse order. The last write (to the Seconds
513 	 * register) will undo the Clock Hold, above.
514 	 */
515 	uint8_t op = I2C_OP_WRITE;
516 	for (signed int i = dm->dm_rtc_size - 1; i >= 0; i--) {
517 		cmdbuf[0] = dm->dm_rtc_start + i;
518 		if (dm->dm_rtc_start + i == dm->dm_ch_reg) {
519 			op = I2C_OP_WRITE_WITH_STOP;
520 		}
521 		if ((error = iic_exec(sc->sc_tag, op, sc->sc_address,
522 		    cmdbuf, 1, &bcd[i], 1, I2C_F_POLL)) != 0) {
523 			iic_release_bus(sc->sc_tag, I2C_F_POLL);
524 			aprint_error_dev(sc->sc_dev,
525 			    "%s: failed to write rtc at 0x%x: %d\n",
526 			    __func__, i, error);
527 			/* XXX: Clock Hold is likely still asserted! */
528 			return 0;
529 		}
530 	}
531 	/*
532 	 * If the clock hold register isn't the same register as seconds,
533 	 * we need to reeanble the clock.
534 	 */
535 	if (op != I2C_OP_WRITE_WITH_STOP) {
536 		cmdbuf[0] = dm->dm_ch_reg;
537 		cmdbuf[1] &= ~dm->dm_ch_value;
538 
539 		if ((error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
540 		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1,
541 		    I2C_F_POLL)) != 0) {
542 			iic_release_bus(sc->sc_tag, I2C_F_POLL);
543 			aprint_error_dev(sc->sc_dev,
544 			    "%s: failed to Hold Clock: %d\n",
545 			    __func__, error);
546 			return 0;
547 		}
548 	}
549 
550 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
551 
552 	return 1;
553 }
554 
555 static int
556 dsrtc_gettime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
557 {
558 	struct dsrtc_softc *sc = ch->cookie;
559 	struct timeval check;
560 	int retries;
561 
562 	memset(tv, 0, sizeof(*tv));
563 	memset(&check, 0, sizeof(check));
564 
565 	/*
566 	 * Since we don't support Burst Read, we have to read the clock twice
567 	 * until we get two consecutive identical results.
568 	 */
569 	retries = 5;
570 	do {
571 		dsrtc_clock_read_timeval(sc, &tv->tv_sec);
572 		dsrtc_clock_read_timeval(sc, &check.tv_sec);
573 	} while (memcmp(tv, &check, sizeof(check)) != 0 && --retries);
574 
575 	return 0;
576 }
577 
578 static int
579 dsrtc_settime_timeval(struct todr_chip_handle *ch, struct timeval *tv)
580 {
581 	struct dsrtc_softc *sc = ch->cookie;
582 
583 	if (dsrtc_clock_write_timeval(sc, tv->tv_sec) == 0)
584 		return -1;
585 
586 	return 0;
587 }
588 
589 /*
590  * The RTC probably has a nice Clock Burst Read/Write command, but we can't use
591  * it, since some I2C controllers don't support anything other than single-byte
592  * transfers.
593  */
594 static int
595 dsrtc_clock_read_timeval(struct dsrtc_softc *sc, time_t *tp)
596 {
597 	const struct dsrtc_model * const dm = &sc->sc_model;
598 	uint8_t buf[4];
599 	int error;
600 
601 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
602 		aprint_error_dev(sc->sc_dev,
603 		    "%s: failed to acquire I2C bus: %d\n",
604 		    __func__, error);
605 		return 0;
606 	}
607 
608 	/* read all registers: */
609 	uint8_t reg = dm->dm_rtc_start;
610 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
611 	     &reg, 1, buf, 4, I2C_F_POLL);
612 
613 	/* Done with I2C */
614 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
615 
616 	if (error != 0) {
617 		aprint_error_dev(sc->sc_dev,
618 		    "%s: failed to read rtc at 0x%x: %d\n",
619 		    __func__, reg, error);
620 		return 0;
621 	}
622 
623 	uint32_t v = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
624 	*tp = v;
625 
626 	aprint_debug_dev(sc->sc_dev, "%s: cntr=0x%08"PRIx32"\n",
627 	    __func__, v);
628 
629 	return 1;
630 }
631 
632 static int
633 dsrtc_clock_write_timeval(struct dsrtc_softc *sc, time_t t)
634 {
635 	const struct dsrtc_model * const dm = &sc->sc_model;
636 	size_t buflen = dm->dm_rtc_size + 2;
637 	uint8_t buf[buflen];
638 	int error;
639 
640 	KASSERT((dm->dm_flags & DSRTC_FLAG_CLOCK_HOLD) == 0);
641 	KASSERT(dm->dm_ch_reg == dm->dm_rtc_start + 4);
642 
643 	buf[0] = dm->dm_rtc_start;
644 	buf[1] = (t >> 0) & 0xff;
645 	buf[2] = (t >> 8) & 0xff;
646 	buf[3] = (t >> 16) & 0xff;
647 	buf[4] = (t >> 24) & 0xff;
648 	buf[5] = 0;
649 
650 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
651 		aprint_error_dev(sc->sc_dev,
652 		    "%s: failed to acquire I2C bus: %d\n",
653 		    __func__, error);
654 		return 0;
655 	}
656 
657 	error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
658 	    &buf, buflen, NULL, 0, I2C_F_POLL);
659 
660 	/* Done with I2C */
661 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
662 
663 	/* send data */
664 	if (error != 0) {
665 		aprint_error_dev(sc->sc_dev,
666 		    "%s: failed to set time: %d\n",
667 		    __func__, error);
668 		return 0;
669 	}
670 
671 	return 1;
672 }
673 
674 static int
675 dsrtc_read_temp(struct dsrtc_softc *sc, uint32_t *temp)
676 {
677 	int error, tc;
678 	uint8_t reg = DS3232_TEMP_MSB;
679 	uint8_t buf[2];
680 
681 	if ((sc->sc_model.dm_flags & DSRTC_FLAG_TEMP) == 0)
682 		return ENOTSUP;
683 
684 	if ((error = iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) != 0) {
685 		aprint_error_dev(sc->sc_dev,
686 		    "%s: failed to acquire I2C bus: %d\n",
687 		    __func__, error);
688 		return 0;
689 	}
690 
691 	/* read temperature registers: */
692 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_address,
693 	     &reg, 1, buf, 2, I2C_F_POLL);
694 
695 	/* Done with I2C */
696 	iic_release_bus(sc->sc_tag, I2C_F_POLL);
697 
698 	if (error != 0) {
699 		aprint_error_dev(sc->sc_dev,
700 		    "%s: failed to read temperature: %d\n",
701 		    __func__, error);
702 		return 0;
703 	}
704 
705 	/* convert to microkelvin */
706 	tc = buf[0] * 1000000 + (buf[1] >> 6) * 250000;
707 	*temp = tc + 273150000;
708 	return 1;
709 }
710 
711 static void
712 dsrtc_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
713 {
714 	struct dsrtc_softc *sc = sme->sme_cookie;
715 	uint32_t temp = 0;	/* XXX gcc */
716 
717 	if (dsrtc_read_temp(sc, &temp) == 0) {
718 		edata->state = ENVSYS_SINVALID;
719 		return;
720 	}
721 
722 	edata->value_cur = temp;
723 
724 	edata->state = ENVSYS_SVALID;
725 }
726