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      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 1.13 2021/06/14 13:52:11 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 	bool sc_multi_read;
     91 
     92 	uint8_t sc_rev, sc_cfg[2];
     93 	int sc_nfans, sc_ntemps;	/* Map sysmon numbers to sensors */
     94 	int sc_fandiv[ADM1026_MAX_FANS], sc_temp_off[ADM1026_MAX_TEMPS];
     95 	struct sysmon_envsys *sc_sme;
     96 	envsys_data_t sc_sensor[ADM1026_MAX_FANS + ADM1026_MAX_TEMPS +
     97 	    ADM1026_MAX_VOLTS];
     98 };
     99 
    100 static int adm1026_match(device_t, cfdata_t, void *);
    101 static int adm1026_ident(i2c_tag_t, i2c_addr_t, int, uint8_t*);
    102 static void adm1026_attach(device_t, device_t, void *);
    103 static int adm1026_detach(device_t, int);
    104 bool adm1026_pmf_suspend(device_t, const pmf_qual_t *);
    105 bool adm1026_pmf_resume(device_t, const pmf_qual_t *);
    106 
    107 static int adm1026_setup_fans(struct adm1026_softc *sc, int div2_val);
    108 static int adm1026_setup_temps(struct adm1026_softc *sc);
    109 static int adm1026_setup_volts(struct adm1026_softc *sc);
    110 
    111 void adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata);
    112 static void adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata);
    113 static void adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata);
    114 static void adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata);
    115 
    116 static int adm1026_read_reg_int(i2c_tag_t, i2c_addr_t,
    117     uint8_t reg, bool multi_read, uint8_t *val);
    118 static int adm1026_write_reg(struct adm1026_softc *sc,
    119     uint8_t reg, uint8_t val);
    120 
    121 static inline int
    122 adm1026_read_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t *val)
    123 {
    124 	return adm1026_read_reg_int(sc->sc_tag, sc->sc_address, reg,
    125 	    sc->sc_multi_read, val);
    126 }
    127 
    128 CFATTACH_DECL_NEW(adm1026hm, sizeof(struct adm1026_softc),
    129 	adm1026_match, adm1026_attach, adm1026_detach, NULL);
    130 
    131 static const struct device_compatible_entry compat_data[] = {
    132 	{ .compat = "i2c-adm1026" },
    133 	DEVICE_COMPAT_EOL
    134 };
    135 
    136 static int
    137 adm1026_match(device_t parent, cfdata_t cf, void *aux)
    138 {
    139 	struct i2c_attach_args *ia = aux;
    140 	int match_result;
    141 	uint8_t rev;
    142 
    143 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
    144 		return match_result;
    145 
    146 	if (ia->ia_addr == ADM1026_ADDR1
    147 	    && adm1026_ident(ia->ia_tag, ia->ia_addr, 1, &rev))
    148 		return I2C_MATCH_ADDRESS_AND_PROBE;
    149 
    150 	return 0;
    151 }
    152 
    153 static int
    154 adm1026_ident(i2c_tag_t tag, i2c_addr_t addr, int probe_only, uint8_t *rev)
    155 {
    156 	uint8_t val;
    157 	int err;
    158 
    159 	/* Manufacturer ID and revision/stepping */
    160 	err = adm1026_read_reg_int(tag, addr, ADM1026_ID, false, &val);
    161 	if (err || val != ADM1026_MANF_ID) {
    162 		if (!probe_only)
    163 			aprint_verbose("adm1026_ident: "
    164 			    "manufacturer ID invalid or missing\n");
    165 		return 0;
    166 	}
    167 	err = adm1026_read_reg_int(tag, addr, ADM1026_REV, false, rev);
    168 	if (err || ADM1026_REVISION(*rev) != ADM1026_MANF_REV) {
    169 		if (!probe_only)
    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 
    190 	sc->sc_multi_read = false;
    191 	prop_dictionary_get_bool(props, "multi_read", &sc->sc_multi_read);
    192 	if (prop_dictionary_get_uint8(props, "fan_div2", &fan_div2) != 0)
    193 		div2_val = fan_div2;
    194 	else
    195 		div2_val = -1;
    196 
    197 	(void) adm1026_ident(sc->sc_tag, sc->sc_address, 0, &sc->sc_rev);
    198 	aprint_normal(": ADM1026 hardware monitor: rev. 0x%x, step. 0x%x\n",
    199 	    ADM1026_REVISION(sc->sc_rev), ADM1026_STEPPING(sc->sc_rev));
    200 
    201 	/*
    202 	 * Start monitoring if not already monitoring.
    203 	 * Wait 1.8s for the fan readings to stabilise.
    204 	 */
    205 	if ((err = adm1026_read_reg(sc, ADM1026_CONF1, &val)) != 0) {
    206 		aprint_error_dev(sc->sc_dev, ": unable to read conf1\n");
    207 		return;
    208 	}
    209 	if (!(val & ADM1026_CONF1_MONITOR)) {
    210 		aprint_normal_dev(sc->sc_dev,
    211 		    ": starting monitoring, waiting 1.8s for readings\n");
    212 		val |= ADM1026_CONF1_MONITOR;
    213 		if ((err = adm1026_write_reg(sc, ADM1026_CONF1, val)) != 0) {
    214 			aprint_error_dev(sc->sc_dev,
    215 			    ": unable to write conf1\n");
    216 			return;
    217 		}
    218 		delay(1800000);
    219 	}
    220 	sc->sc_cfg[0] = val;
    221 
    222 	sc->sc_sme = sysmon_envsys_create();
    223 	sc->sc_nfans = 0;
    224 	sc->sc_ntemps = 0;
    225 	if (adm1026_setup_fans(sc, div2_val))
    226 		goto bad;
    227 	if (adm1026_setup_temps(sc))
    228 		goto bad;
    229 	if (adm1026_setup_volts(sc))
    230 		goto bad;
    231 	aprint_normal_dev(self, "%d fans, %d temperatures, %d voltages\n",
    232 	    sc->sc_nfans, sc->sc_ntemps, sc->sc_ntemps == 3 ? 15 : 17);
    233 
    234         sc->sc_sme->sme_name = device_xname(self);
    235         sc->sc_sme->sme_cookie = sc;
    236         sc->sc_sme->sme_refresh = adm1026_refresh;
    237 	if (sysmon_envsys_register(sc->sc_sme)) {
    238 		aprint_error_dev(self,
    239 		    "unable to register with sysmon\n");
    240 		goto bad;
    241 	}
    242 
    243 	if (!pmf_device_register(self, adm1026_pmf_suspend, adm1026_pmf_resume))
    244 		aprint_error_dev(self, "couldn't establish power handler\n");
    245 
    246 	return;
    247 
    248 bad:
    249 	sysmon_envsys_destroy(sc->sc_sme);
    250 	sc->sc_sme = NULL;
    251 	return;
    252 }
    253 
    254 /*
    255  * We could stop (suspend/detach) and restart (resume) monitoring,
    256  * but we don't do that because some machines have separate
    257  * management hardware which can read the sensors.
    258  */
    259 bool
    260 adm1026_pmf_suspend(device_t dev, const pmf_qual_t *qual)
    261 {
    262 	return true;
    263 }
    264 
    265 bool
    266 adm1026_pmf_resume(device_t dev, const pmf_qual_t *qual)
    267 {
    268 	return true;
    269 }
    270 
    271 static int
    272 adm1026_detach(device_t self, int flags)
    273 {
    274 	struct adm1026_softc *sc = device_private(self);
    275 
    276 	pmf_device_deregister(self);
    277 
    278 	if (sc->sc_sme != NULL)
    279 		sysmon_envsys_unregister(sc->sc_sme);
    280 
    281 	return 0;
    282 }
    283 
    284 static int
    285 adm1026_setup_fans(struct adm1026_softc *sc, int div2_val)
    286 {
    287 	int i, err = 0;
    288 	uint8_t div1, div2;
    289 
    290 	/* Read fan-related registers (configuration and divisors) */
    291 	if ((err = adm1026_read_reg(sc, ADM1026_CONF2, &sc->sc_cfg[1])) != 0) {
    292 		aprint_error_dev(sc->sc_dev, "unable to read conf2\n");
    293 		return 0;
    294 	}
    295 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_DIV1, &div1)) != 0) {
    296 		aprint_error_dev(sc->sc_dev, "unable to read fan_div1\n");
    297 		return 0;
    298 	}
    299 	sc->sc_fandiv[0] = 1 << ADM1026_FAN0_DIV(div1);
    300 	sc->sc_fandiv[1] = 1 << ADM1026_FAN1_DIV(div1);
    301 	sc->sc_fandiv[2] = 1 << ADM1026_FAN2_DIV(div1);
    302 	sc->sc_fandiv[3] = 1 << ADM1026_FAN3_DIV(div1);
    303 	if (div2_val < 0) {
    304 		if ((err =
    305 		    adm1026_read_reg(sc, ADM1026_FAN_DIV2, &div2)) != 0) {
    306 			aprint_error_dev(sc->sc_dev,
    307 			    "unable to read fan_div2\n");
    308 			return 0;
    309 		}
    310 	} else
    311 		div2 = div2_val;
    312 	sc->sc_fandiv[4] = 1 << ADM1026_FAN4_DIV(div2);
    313 	sc->sc_fandiv[5] = 1 << ADM1026_FAN5_DIV(div2);
    314 	sc->sc_fandiv[6] = 1 << ADM1026_FAN6_DIV(div2);
    315 	sc->sc_fandiv[7] = 1 << ADM1026_FAN7_DIV(div2);
    316 
    317 	for (i = 0; i < ADM1026_MAX_FANS; i++) {
    318 		sc->sc_sensor[ADM1026_FAN_NUM(i)].state = ENVSYS_SINVALID;
    319 		/* Check configuration2 register to see which pins are fans. */
    320 		if (ADM1026_PIN_IS_FAN(sc->sc_cfg[1], i)) {
    321 			sc->sc_sensor[ADM1026_FAN_NUM(i)].units =
    322 			    ENVSYS_SFANRPM;
    323 			snprintf(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc,
    324 			    sizeof(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc),
    325 			    "fan %d", ADM1026_FAN_NUM(i));
    326 			if (sysmon_envsys_sensor_attach(
    327 			    sc->sc_sme, &sc->sc_sensor[ADM1026_FAN_NUM(i)])) {
    328 				aprint_error_dev(sc->sc_dev,
    329 				    "unable to attach fan %d at sysmon\n", i);
    330 				return 1;
    331 			}
    332 			sc->sc_nfans++;
    333 		}
    334 	}
    335 	return 0;
    336 }
    337 
    338 static int
    339 adm1026_setup_temps(struct adm1026_softc *sc)
    340 {
    341 	int i;
    342 	uint8_t val;
    343 
    344 	/* Temperature offsets */
    345 	if (adm1026_read_reg(sc, ADM1026_INT_TEMP_OFF, &val)
    346 	    != 0) {
    347 		aprint_error_dev(sc->sc_dev, "unable to read int temp. off.\n");
    348 		return 0;
    349 	}
    350 	if (val & 0x80)
    351 		sc->sc_temp_off[0] = 0 - 1000000 * (val & 0x7f);
    352 	else
    353 		sc->sc_temp_off[0] = 1000000 * (val & 0x7f);
    354 	if (adm1026_read_reg(sc, ADM1026_TDM1_OFF, &val) != 0) {
    355 		aprint_error_dev(sc->sc_dev, "unable to read tdm1 off.\n");
    356 		return 0;
    357 	}
    358 	if (val & 0x80)
    359 		sc->sc_temp_off[1] = 0 - 1000000 * (val & 0x7f);
    360 	else
    361 		sc->sc_temp_off[1] = 1000000 * (val & 0x7f);
    362 	if (adm1026_read_reg(sc, ADM1026_TDM2_OFF, &val) != 0) {
    363 		aprint_error_dev(sc->sc_dev, "unable to read tdm2 off.\n");
    364 		return 0;
    365 	}
    366 	if (val & 0x80)
    367 		sc->sc_temp_off[2] = 0 - 1000000 * (val & 0x7f);
    368 	else
    369 		sc->sc_temp_off[2] = 1000000 * (val & 0x7f);
    370 
    371 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc, "internal",
    372 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc));
    373 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc, "external 1",
    374 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc));
    375 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc, "external 2",
    376 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc));
    377 	for (i = 0; i < ADM1026_MAX_TEMPS; i++) {
    378 		/* Check configuration1 register to see if TDM2 is configured */
    379 		if (i == 2 && !ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
    380 			continue;
    381 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].units = ENVSYS_STEMP;
    382 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].state = ENVSYS_SINVALID;
    383 		if (sysmon_envsys_sensor_attach(
    384 		    sc->sc_sme, &sc->sc_sensor[ADM1026_TEMP_NUM(i)])) {
    385 			aprint_error_dev(sc->sc_dev,
    386 			    "unable to attach temp %d at sysmon\n", i);
    387 			return 1;
    388 		}
    389 		sc->sc_ntemps++;
    390 	}
    391 	return 0;
    392 }
    393 
    394 static int
    395 adm1026_setup_volts(struct adm1026_softc *sc)
    396 {
    397 	int i;
    398 
    399 	for (i = 0; i < ADM1026_MAX_VOLTS; i++) {
    400 		/* Check configuration1 register to see if TDM2 is configured */
    401 		if (adm1026_volts_table[i].check_tdm2 &&
    402 		    ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
    403 			continue;
    404 		strlcpy(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc,
    405 		    adm1026_volts_table[i].desc,
    406 		    sizeof(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc));
    407 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].units = ENVSYS_SVOLTS_DC;
    408 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].state = ENVSYS_SINVALID;
    409 		if (sysmon_envsys_sensor_attach(
    410 		    sc->sc_sme, &sc->sc_sensor[ADM1026_VOLT_NUM(i)])) {
    411 			aprint_error_dev(sc->sc_dev,
    412 			    "unable to attach volts %d at sysmon\n", i);
    413 			return 1;
    414 		}
    415 	}
    416 	return 0;
    417 }
    418 
    419 void
    420 adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
    421 {
    422 	struct adm1026_softc *sc = sme->sme_cookie;
    423 
    424 	if (edata->sensor < sc->sc_nfans)
    425 		adm1026_read_fan(sc, edata);
    426 	else if (edata->sensor < sc->sc_nfans + sc->sc_ntemps)
    427 		adm1026_read_temp(sc, edata);
    428 	else
    429 		adm1026_read_volt(sc, edata);
    430 }
    431 
    432 static void
    433 adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata)
    434 {
    435 	int fan = ADM1026_NUM_FAN(edata->sensor);
    436 	int err;
    437 	uint8_t	val;
    438 
    439 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_VAL(fan), &val)) != 0) {
    440 		edata->state = ENVSYS_SINVALID;
    441 		return;
    442 	}
    443 	if (val == 0xff || val == 0x00)	/* Fan missing or stopped */
    444 		edata->value_cur = 0;
    445 	else
    446 		edata->value_cur = 1350000 / (val * sc->sc_fandiv[fan]);
    447 	edata->state = ENVSYS_SVALID;
    448 }
    449 
    450 static void
    451 adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata)
    452 {
    453 	int temp = ADM1026_NUM_TEMP(edata->sensor);
    454 	int err;
    455 	uint8_t	val;
    456 
    457 	if (temp == 0)
    458 		err = adm1026_read_reg(sc, ADM1026_INT_TEMP_VAL, &val);
    459 	else if (temp == 1)
    460 		err = adm1026_read_reg(sc, ADM1026_TDM1_VAL, &val);
    461 	else
    462 		err = adm1026_read_reg(sc, ADM1026_TDM2_AIN9_VAL, &val);
    463 	if (err) {
    464 		edata->state = ENVSYS_SINVALID;
    465 		return;
    466 	}
    467 
    468 	if (val & 0x80)	/* Negative temperature */
    469 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] -
    470 		    1000000 * (val & 0x7f);
    471 	else		/* Positive temperature */
    472 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] +
    473 		    1000000 * val;
    474 	edata->state = ENVSYS_SVALID;
    475 }
    476 
    477 static void
    478 adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata)
    479 {
    480 	int volt = ADM1026_NUM_VOLT(edata->sensor);
    481 	int err;
    482 	uint8_t	val;
    483 
    484 	err = adm1026_read_reg(sc, adm1026_volts_table[volt].reg, &val);
    485 	if (err) {
    486 		edata->state = ENVSYS_SINVALID;
    487 		return;
    488 	}
    489 	/* Vbatt is not valid for < 1.5V */
    490 	if (volt == 0 && val < 0x60)
    491 		edata->state = ENVSYS_SINVALID;
    492 	edata->value_cur = (int) val * adm1026_volts_table[volt].incr;
    493 	edata->state = ENVSYS_SVALID;
    494 }
    495 
    496 static int
    497 adm1026_read_reg_int(i2c_tag_t tag, i2c_addr_t addr, uint8_t reg,
    498     bool multi_read, uint8_t *val)
    499 {
    500 #define ADM1026_READ_RETRIES	5
    501 	int i, j, err = 0;
    502 	uint8_t creg, cval, tmp[ADM1026_READ_RETRIES + 1];
    503 
    504 	if ((err = iic_acquire_bus(tag, 0)) != 0)
    505 		return err;
    506 	/* Standard ADM1026 */
    507 	if (multi_read == false) {
    508 		err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
    509 		    addr, &reg, 1, val, 1, 0);
    510 	/*
    511 	 * The ADM1026 found in some Sun machines sometimes reads bogus values.
    512 	 * We'll read at least twice and check that we get (nearly) the same
    513 	 * value.  If not, we'll read another register and then re-read the
    514 	 * first.
    515 	 */
    516 	} else {
    517 		if (reg == ADM1026_CONF1)
    518 			creg = ADM1026_CONF2;
    519 		else
    520 			creg = ADM1026_CONF1;
    521 		if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
    522 		    addr, &reg, 1, &tmp[0], 1, 0)) != 0) {
    523 			iic_release_bus(tag, 0);
    524 			return err;
    525 		}
    526 		for (i = 1; i <= ADM1026_READ_RETRIES; i++) {
    527 			if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
    528 			    addr, &reg, 1, &tmp[i], 1, 0)) != 0)
    529 				break;
    530 			for (j = 0; j < i; j++)
    531 				if (abs(tmp[j] - tmp[i]) < 3) {
    532 					*val = tmp[i];
    533 					iic_release_bus(tag, 0);
    534 					return 0;
    535 				}
    536 			if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
    537 			    addr, &creg, 1, &cval, 1, 0)) != 0)
    538 				break;
    539 			err = -1;	/* Return error if we don't match. */
    540 		}
    541 	}
    542 	iic_release_bus(tag, 0);
    543 	return err;
    544 }
    545 
    546 static int
    547 adm1026_write_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t val)
    548 {
    549 	int err = 0;
    550 
    551 	if ((err = iic_acquire_bus(sc->sc_tag, 0)) != 0)
    552 		return err;
    553 	err = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
    554 	    &reg, 1, &val, 1, 0);
    555 	iic_release_bus(sc->sc_tag, 0);
    556 	return err;
    557 }
    558