xref: /netbsd-src/sys/dev/i2c/adm1026.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /*-
2  * Copyright (c) 2015 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Julian Coleman.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __KERNEL_RCSID(0, "$NetBSD: adm1026.c,v 1.2 2016/01/11 18:23:52 jdc Exp $");
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/device.h>
36 #include <sys/kernel.h>
37 #include <sys/sysctl.h>
38 
39 #include <dev/sysmon/sysmonvar.h>
40 
41 #include <dev/i2c/i2cvar.h>
42 #include <dev/i2c/adm1026reg.h>
43 
44 /* Voltage/analog sensors descriptions and registers */
45 struct adm1026_volts_info {
46 	const char* desc;
47 	int incr;
48 	uint8_t reg, check_tdm2;
49 };
50 
51 /* Voltage maximums (in mV) from datasheet table 7 divided by 255 increments */
52 static struct adm1026_volts_info adm1026_volts_table[] = {
53 	{ "Vbatt", 15624, ADM1026_VBAT_VAL, 0 },
54 	{ "V3.3 standby", 17345, ADM1026_33VSTBY_VAL, 0 },
55 	{ "V3.3 main", 17345, ADM1026_33VMAIN_VAL, 0 },
56 	{ "V5.0", 26016, ADM1026_50V_VAL, 0 },
57 	{ "Vccp", 11718, ADM1026_VCCP_VAL, 0 },
58 	{ "V+12", 62502, ADM1026_12V_VAL, 0 },
59 	{ "V-12", -62502, ADM1026_N12V_VAL, 0 },
60 	{ "V3.0 0", 11718, ADM1026_AIN_VAL(0), 0 },
61 	{ "V3.0 1", 11718, ADM1026_AIN_VAL(1), 0 },
62 	{ "V3.0 2", 11718, ADM1026_AIN_VAL(2), 0 },
63 	{ "V3.0 3", 11718, ADM1026_AIN_VAL(3), 0 },
64 	{ "V3.0 4", 11718, ADM1026_AIN_VAL(4), 0 },
65 	{ "V3.0 5", 11718, ADM1026_AIN_VAL(5), 0 },
66 	{ "V2.5 0", 9765, ADM1026_AIN_VAL(6), 0 },
67 	{ "V2.5 1", 9765, ADM1026_AIN_VAL(7), 0 },
68 	{ "V2.5 2", 9765, ADM1026_AIN8_VAL, 1 },
69 	{ "V2.5 3", 9765, ADM1026_TDM2_AIN9_VAL, 1 }
70 };
71 
72 /* Maximum number of each type of sensor */
73 #define ADM1026_MAX_FANS	8
74 #define ADM1026_MAX_TEMPS	3
75 #define ADM1026_MAX_VOLTS	(sizeof(adm1026_volts_table) / \
76 				    sizeof (adm1026_volts_table[0]))
77 
78 /* Map sensor to/from sysmon numbers */
79 #define ADM1026_FAN_NUM(x)	(x)
80 #define ADM1026_TEMP_NUM(x)	(x + sc->sc_nfans)
81 #define ADM1026_VOLT_NUM(x)	(x + sc->sc_nfans + sc->sc_ntemps)
82 #define ADM1026_NUM_FAN(x)	(x)
83 #define ADM1026_NUM_TEMP(x)	(x - sc->sc_nfans)
84 #define ADM1026_NUM_VOLT(x)	(x - sc->sc_nfans - sc->sc_ntemps)
85 
86 struct adm1026_softc {
87 	device_t sc_dev;
88 	i2c_tag_t sc_tag;
89 	int sc_address;
90 	int sc_iic_flags;
91 	bool sc_multi_read;
92 
93 	uint8_t sc_rev, sc_cfg[2];
94 	int sc_nfans, sc_ntemps;	/* Map sysmon numbers to sensors */
95 	int sc_fandiv[ADM1026_MAX_FANS], sc_temp_off[ADM1026_MAX_TEMPS];
96 	struct sysmon_envsys *sc_sme;
97 	envsys_data_t sc_sensor[ADM1026_MAX_FANS + ADM1026_MAX_TEMPS +
98 	    ADM1026_MAX_VOLTS];
99 };
100 
101 static int adm1026_match(device_t, cfdata_t, void *);
102 static int adm1026_ident(struct adm1026_softc *sc);
103 static void adm1026_attach(device_t, device_t, void *);
104 static int adm1026_detach(device_t, int);
105 bool adm1026_pmf_suspend(device_t dev, const pmf_qual_t *qual);
106 bool adm1026_pmf_resume(device_t dev, const pmf_qual_t *qual);
107 
108 static void adm1026_setup_fans(struct adm1026_softc *sc, int div2_val);
109 static void adm1026_setup_temps(struct adm1026_softc *sc);
110 static void adm1026_setup_volts(struct adm1026_softc *sc);
111 
112 void adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata);
113 static void adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata);
114 static void adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata);
115 static void adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata);
116 
117 static int adm1026_read_reg(struct adm1026_softc *sc,
118     uint8_t reg, uint8_t *val);
119 static int adm1026_write_reg(struct adm1026_softc *sc,
120     uint8_t reg, uint8_t val);
121 
122 CFATTACH_DECL_NEW(adm1026hm, sizeof(struct adm1026_softc),
123 	adm1026_match, adm1026_attach, adm1026_detach, NULL);
124 
125 static const char * adm1026_compats[] = {
126 	"i2c-adm1026",
127 	NULL
128 };
129 
130 static int
131 adm1026_match(device_t parent, cfdata_t cf, void *aux)
132 {
133 	struct i2c_attach_args *ia = aux;
134 	struct adm1026_softc sc;	/* For chip ident */
135 	sc.sc_tag = ia->ia_tag;
136 	sc.sc_address = ia->ia_addr;
137 	sc.sc_iic_flags = 0;
138 
139 	/* Direct config - match compats */
140 	if (ia->ia_name) {
141 		if (ia->ia_ncompat > 0) {
142 			if (iic_compat_match(ia, adm1026_compats))
143 				return 1;
144 		}
145 	/* Indirect config - check address and chip ID/rev. */
146 	} else {
147 		if ((ia->ia_addr & ADM1026_ADDRMASK) == ADM1026_ADDR &&
148 		    adm1026_ident(&sc))
149 			return 1;
150 	}
151 
152 	return 0;
153 }
154 
155 static int
156 adm1026_ident(struct adm1026_softc *sc)
157 {
158 	uint8_t val;
159 	int err;
160 
161 	/* Manufacturer ID and revision/stepping */
162 	err = adm1026_read_reg(sc, ADM1026_ID, &val);
163 	if (err || val != ADM1026_MANF_ID) {
164 		aprint_verbose("adm1026_ident: "
165 		    "manufacturer ID invalid or missing\n");
166 		return 0;
167 	}
168 	err = adm1026_read_reg(sc, ADM1026_REV, &sc->sc_rev);
169 	if (err || ADM1026_REVISION(sc->sc_rev) != ADM1026_MANF_REV) {
170 		aprint_verbose("adm1026_ident: "
171 		    "manufacturer revision invalid or missing\n");
172 		return 0;
173 	}
174 	return 1;
175 }
176 
177 static void
178 adm1026_attach(device_t parent, device_t self, void *aux)
179 {
180 	struct adm1026_softc *sc = device_private(self);
181 	struct i2c_attach_args *ia = aux;
182 	prop_dictionary_t props = device_properties(self);
183 	uint8_t val, fan_div2;
184 	int err, div2_val;
185 
186 	sc->sc_tag = ia->ia_tag;
187 	sc->sc_address = ia->ia_addr;
188 	sc->sc_dev = self;
189 	sc->sc_iic_flags = I2C_F_POLL;	/* Use polling during autoconf */
190 
191 	sc->sc_multi_read = false;
192 	prop_dictionary_get_bool(props, "multi_read", &sc->sc_multi_read);
193 	if (prop_dictionary_get_uint8(props, "fan_div2", &fan_div2) != 0)
194 		div2_val = fan_div2;
195 	else
196 		div2_val = -1;
197 
198 	(void) adm1026_ident(sc);
199 	aprint_normal(": ADM1026 hardware monitor: rev. 0x%x, step. 0x%x\n",
200 	    ADM1026_REVISION(sc->sc_rev), ADM1026_STEPPING(sc->sc_rev));
201 
202 	/*
203 	 * Start monitoring if not already monitoring.
204 	 * Wait 1.8s for the fan readings to stabilise.
205 	 */
206 	if ((err = adm1026_read_reg(sc, ADM1026_CONF1, &val)) != 0) {
207 		aprint_error_dev(sc->sc_dev, ": unable to read conf1\n");
208 		return;
209 	}
210 	if (!(val & ADM1026_CONF1_MONITOR)) {
211 		aprint_normal_dev(sc->sc_dev,
212 		    ": starting monitoring, waiting 1.8s for readings\n");
213 		val |= ADM1026_CONF1_MONITOR;
214 		if ((err = adm1026_write_reg(sc, ADM1026_CONF1, val)) != 0) {
215 			aprint_error_dev(sc->sc_dev,
216 			    ": unable to write conf1\n");
217 			return;
218 		}
219 		delay(1800000);
220 	}
221 	sc->sc_cfg[0] = val;
222 
223 	sc->sc_sme = sysmon_envsys_create();
224 	sc->sc_nfans = 0;
225 	adm1026_setup_fans(sc, div2_val);
226 	sc->sc_ntemps = 0;
227 	adm1026_setup_temps(sc);
228 	adm1026_setup_volts(sc);
229 	aprint_normal_dev(self, "%d fans, %d temperatures, %d voltages\n",
230 	    sc->sc_nfans, sc->sc_ntemps, sc->sc_ntemps == 3 ? 15 : 17);
231 
232         sc->sc_sme->sme_name = device_xname(self);
233         sc->sc_sme->sme_cookie = sc;
234         sc->sc_sme->sme_refresh = adm1026_refresh;
235 	if (sysmon_envsys_register(sc->sc_sme)) {
236 		aprint_error_dev(self,
237 		    "unable to register with sysmon\n");
238 		sysmon_envsys_destroy(sc->sc_sme);
239 		return;
240 	}
241 
242 	if (!pmf_device_register(self, adm1026_pmf_suspend, adm1026_pmf_resume))
243 		aprint_error_dev(self, "couldn't establish power handler\n");
244 
245 	sc->sc_iic_flags = 0;	/* Drop polling flag */
246 
247 	return;
248 }
249 
250 /*
251  * We could stop (suspend/detach) and restart (resume) monitoring,
252  * but we don't do that because some machines have separate
253  * management hardware which can read the sensors.
254  */
255 bool
256 adm1026_pmf_suspend(device_t dev, const pmf_qual_t *qual)
257 {
258 	return true;
259 }
260 
261 bool
262 adm1026_pmf_resume(device_t dev, const pmf_qual_t *qual)
263 {
264 	return true;
265 }
266 
267 static int
268 adm1026_detach(device_t self, int flags)
269 {
270 	struct adm1026_softc *sc = device_private(self);
271 
272 	pmf_device_deregister(self);
273 
274 	sysmon_envsys_unregister(sc->sc_sme);
275 	sc->sc_sme = NULL;
276 
277 	return 0;
278 }
279 
280 static void
281 adm1026_setup_fans(struct adm1026_softc *sc, int div2_val)
282 {
283 	int i, err = 0;
284 	uint8_t div1, div2;
285 
286 	/* Read fan-related registers (configuration and divisors) */
287 	if ((err = adm1026_read_reg(sc, ADM1026_CONF2, &sc->sc_cfg[1])) != 0) {
288 		aprint_error_dev(sc->sc_dev, "unable to read conf2\n");
289 		return;
290 	}
291 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_DIV1, &div1)) != 0) {
292 		aprint_error_dev(sc->sc_dev, "unable to read fan_div1\n");
293 		return;
294 	}
295 	sc->sc_fandiv[0] = 1 << ADM1026_FAN0_DIV(div1);
296 	sc->sc_fandiv[1] = 1 << ADM1026_FAN1_DIV(div1);
297 	sc->sc_fandiv[2] = 1 << ADM1026_FAN2_DIV(div1);
298 	sc->sc_fandiv[3] = 1 << ADM1026_FAN3_DIV(div1);
299 	if (div2_val < 0) {
300 		if ((err =
301 		    adm1026_read_reg(sc, ADM1026_FAN_DIV2, &div2)) != 0) {
302 			aprint_error_dev(sc->sc_dev,
303 			    "unable to read fan_div2\n");
304 			return;
305 		}
306 	} else
307 		div2 = div2_val;
308 	sc->sc_fandiv[4] = 1 << ADM1026_FAN4_DIV(div2);
309 	sc->sc_fandiv[5] = 1 << ADM1026_FAN5_DIV(div2);
310 	sc->sc_fandiv[6] = 1 << ADM1026_FAN6_DIV(div2);
311 	sc->sc_fandiv[7] = 1 << ADM1026_FAN7_DIV(div2);
312 
313 	for (i = 0; i < ADM1026_MAX_FANS; i++) {
314 		sc->sc_sensor[ADM1026_FAN_NUM(i)].state = ENVSYS_SINVALID;
315 		/* Check configuration2 register to see which pins are fans. */
316 		if (ADM1026_PIN_IS_FAN(sc->sc_cfg[1], i)) {
317 			sc->sc_sensor[ADM1026_FAN_NUM(i)].units =
318 			    ENVSYS_SFANRPM;
319 			snprintf(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc,
320 			    sizeof(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc),
321 			    "fan %d", ADM1026_FAN_NUM(i));
322 			sc->sc_nfans++;
323 			if (sysmon_envsys_sensor_attach(
324 			    sc->sc_sme, &sc->sc_sensor[ADM1026_FAN_NUM(i)])) {
325 				sysmon_envsys_destroy(sc->sc_sme);
326 				aprint_error_dev(sc->sc_dev,
327 				    "unable to attach fan %d at sysmon\n", i);
328 				return;
329 			}
330 		}
331 	}
332 }
333 
334 static void
335 adm1026_setup_temps(struct adm1026_softc *sc)
336 {
337 	int i;
338 	uint8_t val;
339 
340 	/* Temperature offsets */
341 	if (adm1026_read_reg(sc, ADM1026_INT_TEMP_OFF, &val)
342 	    != 0) {
343 		aprint_error_dev(sc->sc_dev, "unable to read int temp. off.\n");
344 		return;
345 	}
346 	if (val & 0x80)
347 		sc->sc_temp_off[0] = 0 - 1000000 * (val & 0x7f);
348 	else
349 		sc->sc_temp_off[0] = 1000000 * (val & 0x7f);
350 	if (adm1026_read_reg(sc, ADM1026_TDM1_OFF, &val) != 0) {
351 		aprint_error_dev(sc->sc_dev, "unable to read tdm1 off.\n");
352 		return;
353 	}
354 	if (val & 0x80)
355 		sc->sc_temp_off[1] = 0 - 1000000 * (val & 0x7f);
356 	else
357 		sc->sc_temp_off[1] = 1000000 * (val & 0x7f);
358 	if (adm1026_read_reg(sc, ADM1026_TDM2_OFF, &val) != 0) {
359 		aprint_error_dev(sc->sc_dev, "unable to read tdm2 off.\n");
360 		return;
361 	}
362 	if (val & 0x80)
363 		sc->sc_temp_off[2] = 0 - 1000000 * (val & 0x7f);
364 	else
365 		sc->sc_temp_off[2] = 1000000 * (val & 0x7f);
366 
367 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc, "internal",
368 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc));
369 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc, "external 1",
370 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc));
371 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc, "external 2",
372 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc));
373 	for (i = 0; i < ADM1026_MAX_TEMPS; i++) {
374 		/* Check configuration1 register to see if TDM2 is configured */
375 		if (i == 2 && !ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
376 			continue;
377 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].units = ENVSYS_STEMP;
378 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].state = ENVSYS_SINVALID;
379 		sc->sc_ntemps++;
380 		if (sysmon_envsys_sensor_attach(
381 		    sc->sc_sme, &sc->sc_sensor[ADM1026_TEMP_NUM(i)])) {
382 			sysmon_envsys_destroy(sc->sc_sme);
383 			aprint_error_dev(sc->sc_dev,
384 			    "unable to attach temp %d at sysmon\n", i);
385 			return;
386 		}
387 	}
388 }
389 
390 static void
391 adm1026_setup_volts(struct adm1026_softc *sc)
392 {
393 	int i;
394 
395 	for (i = 0; i < ADM1026_MAX_VOLTS; i++) {
396 		/* Check configuration1 register to see if TDM2 is configured */
397 		if (adm1026_volts_table[i].check_tdm2 &&
398 		    ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
399 			continue;
400 		strlcpy(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc,
401 		    adm1026_volts_table[i].desc,
402 		    sizeof(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc));
403 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].units = ENVSYS_SVOLTS_DC;
404 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].state = ENVSYS_SINVALID;
405 		if (sysmon_envsys_sensor_attach(
406 		    sc->sc_sme, &sc->sc_sensor[ADM1026_VOLT_NUM(i)])) {
407 			sysmon_envsys_destroy(sc->sc_sme);
408 			aprint_error_dev(sc->sc_dev,
409 			    "unable to attach volts %d at sysmon\n", i);
410 			return;
411 		}
412 	}
413 }
414 
415 void
416 adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
417 {
418 	struct adm1026_softc *sc = sme->sme_cookie;
419 
420 	if (edata->sensor < sc->sc_nfans)
421 		adm1026_read_fan(sc, edata);
422 	else if (edata->sensor < sc->sc_nfans + sc->sc_ntemps)
423 		adm1026_read_temp(sc, edata);
424 	else
425 		adm1026_read_volt(sc, edata);
426 }
427 
428 static void
429 adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata)
430 {
431 	int fan = ADM1026_NUM_FAN(edata->sensor);
432 	int err;
433 	uint8_t	val;
434 
435 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_VAL(fan), &val)) != 0) {
436 		edata->state = ENVSYS_SINVALID;
437 		return;
438 	}
439 	if (val == 0xff || val == 0x00)	/* Fan missing or stopped */
440 		edata->value_cur = 0;
441 	else
442 		edata->value_cur = 1350000 / (val * sc->sc_fandiv[fan]);
443 	edata->state = ENVSYS_SVALID;
444 }
445 
446 static void
447 adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata)
448 {
449 	int temp = ADM1026_NUM_TEMP(edata->sensor);
450 	int err;
451 	uint8_t	val;
452 
453 	if (temp == 0)
454 		err = adm1026_read_reg(sc, ADM1026_INT_TEMP_VAL, &val);
455 	else if (temp == 1)
456 		err = adm1026_read_reg(sc, ADM1026_TDM1_VAL, &val);
457 	else
458 		err = adm1026_read_reg(sc, ADM1026_TDM2_AIN9_VAL, &val);
459 	if (err) {
460 		edata->state = ENVSYS_SINVALID;
461 		return;
462 	}
463 
464 	if (val & 0x80)	/* Negative temperature */
465 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] -
466 		    1000000 * (val & 0x7f);
467 	else		/* Positive temperature */
468 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] +
469 		    1000000 * val;
470 	edata->state = ENVSYS_SVALID;
471 }
472 
473 static void
474 adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata)
475 {
476 	int volt = ADM1026_NUM_VOLT(edata->sensor);
477 	int err;
478 	uint8_t	val;
479 
480 	err = adm1026_read_reg(sc, adm1026_volts_table[volt].reg, &val);
481 	if (err) {
482 		edata->state = ENVSYS_SINVALID;
483 		return;
484 	}
485 	/* Vbatt is not valid for < 1.5V */
486 	if (volt == 0 && val < 0x60)
487 		edata->state = ENVSYS_SINVALID;
488 	edata->value_cur = (int) val * adm1026_volts_table[volt].incr;
489 	edata->state = ENVSYS_SVALID;
490 }
491 
492 static int
493 adm1026_read_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t *val)
494 {
495 #define ADM1026_READ_RETRIES	5
496 	int i, j, err = 0;
497 	uint8_t creg, cval, tmp[ADM1026_READ_RETRIES + 1];
498 
499 	if ((err = iic_acquire_bus(sc->sc_tag, sc->sc_iic_flags)) != 0)
500 		return err;
501 	/* Standard ADM1026 */
502 	if (sc->sc_multi_read == false) {
503 		err = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
504 		    sc->sc_address, &reg, 1, val, 1, 0);
505 	/*
506 	 * The ADM1026 found in some Sun machines sometimes reads bogus values.
507 	 * We'll read at least twice and check that we get (nearly) the same
508 	 * value.  If not, we'll read another register and then re-read the
509 	 * first.
510 	 */
511 	} else {
512 		if (reg == ADM1026_CONF1)
513 			creg = ADM1026_CONF2;
514 		else
515 			creg = ADM1026_CONF1;
516 		if ((err = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
517 		    sc->sc_address, &reg, 1, &tmp[0], 1, 0)) != 0) {
518 			iic_release_bus(sc->sc_tag, sc->sc_iic_flags);
519 			return err;
520 		}
521 		for (i = 1; i <= ADM1026_READ_RETRIES; i++) {
522 			if ((err = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
523 			    sc->sc_address, &reg, 1, &tmp[i], 1, 0)) != 0)
524 				break;
525 			for (j = 0; j < i; j++)
526 				if (abs(tmp[j] - tmp[i]) < 3) {
527 					*val = tmp[i];
528 					iic_release_bus(sc->sc_tag,
529 					    sc->sc_iic_flags);
530 					return 0;
531 				}
532 			if ((err = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
533 			    sc->sc_address, &creg, 1, &cval, 1, 0)) != 0)
534 				break;
535 			err = -1;	/* Return error if we don't match. */
536 		}
537 	}
538 	iic_release_bus(sc->sc_tag, sc->sc_iic_flags);
539 	return err;
540 }
541 
542 static int
543 adm1026_write_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t val)
544 {
545 	int err = 0;
546 
547 	if ((err = iic_acquire_bus(sc->sc_tag, sc->sc_iic_flags)) != 0)
548 		return err;
549 	err = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
550 	    &reg, 1, &val, 1, 0);
551 	iic_release_bus(sc->sc_tag, sc->sc_iic_flags);
552 	return err;
553 }
554