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      1 /* $NetBSD: fcu.c,v 1.7 2025/09/17 14:15:59 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2018 Michael Lorenz
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: fcu.c,v 1.7 2025/09/17 14:15:59 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/systm.h>
     34 #include <sys/device.h>
     35 #include <sys/conf.h>
     36 #include <sys/bus.h>
     37 #include <sys/kthread.h>
     38 #include <sys/sysctl.h>
     39 
     40 #include <dev/i2c/i2cvar.h>
     41 
     42 #include <dev/sysmon/sysmonvar.h>
     43 
     44 #include <dev/ofw/openfirm.h>
     45 
     46 #include <macppc/dev/fancontrolvar.h>
     47 
     48 #include "opt_fcu.h"
     49 
     50 #ifdef FCU_DEBUG
     51 #define DPRINTF printf
     52 #else
     53 #define DPRINTF if (0) printf
     54 #endif
     55 
     56 /* FCU registers, from OpenBSD's fcu.c */
     57 #define FCU_FAN_FAIL	0x0b		/* fans states in bits 0<1-6>7 */
     58 #define FCU_FAN_ACTIVE	0x0d
     59 #define FCU_FANREAD(x)	0x11 + (x)*2
     60 #define FCU_FANSET(x)	0x10 + (x)*2
     61 #define FCU_PWM_FAIL	0x2b
     62 #define FCU_PWM_ACTIVE	0x2d
     63 #define FCU_PWMREAD(x)	0x30 + (x)*2
     64 
     65 
     66 typedef struct _fcu_fan {
     67 	int target;
     68 	int reg;
     69 	int base_rpm, max_rpm;
     70 	int step;
     71 	int duty;	/* for pwm fans */
     72 } fcu_fan_t;
     73 
     74 #define FCU_ZONE_CPU		0
     75 #define FCU_ZONE_CASE		1
     76 #define FCU_ZONE_DRIVEBAY	2
     77 #define FCU_ZONE_COUNT		3
     78 
     79 struct fcu_softc {
     80 	device_t	sc_dev;
     81 	i2c_tag_t	sc_i2c;
     82 	i2c_addr_t	sc_addr;
     83 	struct sysctlnode 	*sc_sysctl_me;
     84 	struct sysmon_envsys	*sc_sme;
     85 	envsys_data_t		sc_sensors[32];
     86 	int			sc_nsensors;
     87 	fancontrol_zone_t	sc_zones[FCU_ZONE_COUNT];
     88 	fcu_fan_t		sc_fans[FANCONTROL_MAX_FANS];
     89 	int			sc_nfans;
     90 	lwp_t			*sc_thread;
     91 	bool			sc_dying, sc_pwm;
     92 	uint8_t			sc_eeprom0[160];
     93 	uint8_t			sc_eeprom1[160];
     94 };
     95 
     96 static int	fcu_match(device_t, cfdata_t, void *);
     97 static void	fcu_attach(device_t, device_t, void *);
     98 
     99 static void	fcu_sensors_refresh(struct sysmon_envsys *, envsys_data_t *);
    100 static void	fcu_configure_sensor(struct fcu_softc *, envsys_data_t *);
    101 
    102 static bool is_cpu(const envsys_data_t *);
    103 static bool is_case(const envsys_data_t *);
    104 static bool is_drive(const envsys_data_t *);
    105 
    106 static int fcu_set_rpm(void *, int, int);
    107 static int fcu_get_rpm(void *, int);
    108 static void fcu_adjust(void *);
    109 
    110 CFATTACH_DECL_NEW(fcu, sizeof(struct fcu_softc),
    111     fcu_match, fcu_attach, NULL, NULL);
    112 
    113 static const struct device_compatible_entry compat_data[] = {
    114 	{ .compat = "fcu" },
    115 	DEVICE_COMPAT_EOL
    116 };
    117 
    118 static int
    119 fcu_match(device_t parent, cfdata_t match, void *aux)
    120 {
    121 	struct i2c_attach_args *ia = aux;
    122 	int match_result;
    123 
    124 	if (iic_use_direct_match(ia, match, compat_data, &match_result))
    125 		return match_result;
    126 
    127 	if (ia->ia_addr == 0x2f)
    128 		return I2C_MATCH_ADDRESS_ONLY;
    129 
    130 	return 0;
    131 }
    132 
    133 static void
    134 fcu_attach(device_t parent, device_t self, void *aux)
    135 {
    136 	struct fcu_softc *sc = device_private(self);
    137 	struct i2c_attach_args *ia = aux;
    138 	int phandle = devhandle_to_of(device_handle(self));
    139 	int i;
    140 
    141 	sc->sc_dev = self;
    142 	sc->sc_i2c = ia->ia_tag;
    143 	sc->sc_addr = ia->ia_addr;
    144 
    145 	aprint_naive("\n");
    146 	aprint_normal(": Fan Control Unit\n");
    147 
    148 	sysctl_createv(NULL, 0, NULL, (void *) &sc->sc_sysctl_me,
    149 	    CTLFLAG_READWRITE,
    150 	    CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
    151 	    NULL, 0, NULL, 0,
    152 	    CTL_MACHDEP, CTL_CREATE, CTL_EOL);
    153 
    154 	if (get_cpuid(0, sc->sc_eeprom0) < 160) {
    155 		/*
    156 		 * XXX this should never happen, we depend on the EEPROM for
    157 		 * calibration data to make sense of temperature and voltage
    158 		 * sensors elsewhere, and fan parameters here.
    159 		 */
    160 		aprint_error_dev(self, "no EEPROM data for CPU 0\n");
    161 		return;
    162 	}
    163 
    164 	/* init zones */
    165 	sc->sc_zones[FCU_ZONE_CPU].name = "CPUs";
    166 	sc->sc_zones[FCU_ZONE_CPU].filter = is_cpu;
    167 	sc->sc_zones[FCU_ZONE_CPU].cookie = sc;
    168 	sc->sc_zones[FCU_ZONE_CPU].get_rpm = fcu_get_rpm;
    169 	sc->sc_zones[FCU_ZONE_CPU].set_rpm = fcu_set_rpm;
    170 	sc->sc_zones[FCU_ZONE_CPU].Tmin = 50;
    171 	sc->sc_zones[FCU_ZONE_CPU].Tmax = 85;
    172 	sc->sc_zones[FCU_ZONE_CPU].nfans = 0;
    173 	sc->sc_zones[FCU_ZONE_CASE].name = "Slots";
    174 	sc->sc_zones[FCU_ZONE_CASE].filter = is_case;
    175 	sc->sc_zones[FCU_ZONE_CASE].cookie = sc;
    176 	sc->sc_zones[FCU_ZONE_CASE].Tmin = 50;
    177 	sc->sc_zones[FCU_ZONE_CASE].Tmax = 75;
    178 	sc->sc_zones[FCU_ZONE_CASE].nfans = 0;
    179 	sc->sc_zones[FCU_ZONE_CASE].get_rpm = fcu_get_rpm;
    180 	sc->sc_zones[FCU_ZONE_CASE].set_rpm = fcu_set_rpm;
    181 	sc->sc_zones[FCU_ZONE_DRIVEBAY].name = "Drivebays";
    182 	sc->sc_zones[FCU_ZONE_DRIVEBAY].filter = is_drive;
    183 	sc->sc_zones[FCU_ZONE_DRIVEBAY].cookie = sc;
    184 	sc->sc_zones[FCU_ZONE_DRIVEBAY].get_rpm = fcu_get_rpm;
    185 	sc->sc_zones[FCU_ZONE_DRIVEBAY].set_rpm = fcu_set_rpm;
    186 	sc->sc_zones[FCU_ZONE_DRIVEBAY].Tmin = 30;
    187 	sc->sc_zones[FCU_ZONE_DRIVEBAY].Tmax = 50;
    188 	sc->sc_zones[FCU_ZONE_DRIVEBAY].nfans = 0;
    189 
    190 	sc->sc_sme = sysmon_envsys_create();
    191 	sc->sc_sme->sme_name = device_xname(self);
    192 	sc->sc_sme->sme_cookie = sc;
    193 	sc->sc_sme->sme_refresh = fcu_sensors_refresh;
    194 
    195 	sc->sc_sensors[0].units = ENVSYS_SFANRPM;
    196 	sc->sc_sensors[1].state = ENVSYS_SINVALID;
    197 	sc->sc_nfans = 0;
    198 
    199 	/* round up sensors */
    200 	int ch;
    201 
    202 	sc->sc_nsensors = 0;
    203 	ch = OF_child(phandle);
    204 	if (ch == 0) {
    205 		/* old style data, no individual nodes for fans, annoying */
    206 		char loc[256], tp[256], descr[32], type[32];
    207 		uint32_t reg_rpm = 0x10, reg_pwm = 0x32, reg;
    208 		uint32_t id[16];
    209 		int num, lidx = 0, tidx = 0;
    210 
    211 		num = OF_getprop(phandle, "hwctrl-id", id, 64);
    212 		OF_getprop(phandle, "hwctrl-location", loc, 1024);
    213 		OF_getprop(phandle, "hwctrl-type", tp, 1024);
    214 		while (num > 0) {
    215 			envsys_data_t *s = &sc->sc_sensors[sc->sc_nsensors];
    216 
    217 			s->state = ENVSYS_SINVALID;
    218 			strcpy(descr, &loc[lidx]);
    219 			strcpy(type, &tp[tidx]);
    220 			if (strstr(type, "rpm") != NULL) {
    221 				s->units = ENVSYS_SFANRPM;
    222 				reg = reg_rpm;
    223 				reg_rpm += 2;
    224 			} else if (strstr(type, "pwm") != NULL) {
    225 				s->units = ENVSYS_SFANRPM;
    226 				reg = reg_pwm;
    227 				reg_pwm += 2;
    228 			} else goto skip;
    229 
    230 			s->private = reg;
    231 			strcpy(s->desc, descr);
    232 
    233 			fcu_configure_sensor(sc, s);
    234 
    235 			sysmon_envsys_sensor_attach(sc->sc_sme, s);
    236 			sc->sc_nsensors++;
    237 skip:
    238 			lidx += strlen(descr) + 1;
    239 			tidx += strlen(type) + 1;
    240 			num -= 4;
    241 		}
    242 	} else {
    243 		/* new style, with individual nodes */
    244 		while (ch != 0) {
    245 			char type[32], descr[32];
    246 			uint32_t reg;
    247 
    248 			envsys_data_t *s = &sc->sc_sensors[sc->sc_nsensors];
    249 
    250 			s->state = ENVSYS_SINVALID;
    251 
    252 			if (OF_getprop(ch, "device_type", type, 32) <= 0)
    253 				goto next;
    254 
    255 			if (strcmp(type, "fan-rpm-control") == 0) {
    256 				s->units = ENVSYS_SFANRPM;
    257 			} else if (strcmp(type, "fan-pwm-control") == 0) {
    258 				/* XXX we get the type from the register number */
    259 				s->units = ENVSYS_SFANRPM;
    260 /* skip those for now since we don't really know how to interpret them */
    261 #if 0
    262 			} else if (strcmp(type, "power-sensor") == 0) {
    263 				s->units = ENVSYS_SVOLTS_DC;
    264 #endif
    265 			} else if (strcmp(type, "gpi-sensor") == 0) {
    266 				s->units = ENVSYS_INDICATOR;
    267 			} else {
    268 				/* ignore other types for now */
    269 				goto next;
    270 			}
    271 
    272 			if (OF_getprop(ch, "reg", &reg, sizeof(reg)) <= 0)
    273 				goto next;
    274 			s->private = reg;
    275 
    276 			if (OF_getprop(ch, "location", descr, 32) <= 0)
    277 				goto next;
    278 			strcpy(s->desc, descr);
    279 
    280 			fcu_configure_sensor(sc, s);
    281 
    282 			sysmon_envsys_sensor_attach(sc->sc_sme, s);
    283 			sc->sc_nsensors++;
    284 next:
    285 			ch = OF_peer(ch);
    286 		}
    287 	}
    288 	sysmon_envsys_register(sc->sc_sme);
    289 
    290 	/* setup sysctls for our zones etc. */
    291 	for (i = 0; i < FCU_ZONE_COUNT; i++) {
    292 		fancontrol_init_zone(&sc->sc_zones[i], sc->sc_sysctl_me);
    293 	}
    294 
    295 	sc->sc_dying = FALSE;
    296 	kthread_create(PRI_NONE, 0, curcpu(), fcu_adjust, sc, &sc->sc_thread,
    297 	    "fan control");
    298 }
    299 
    300 static void
    301 fcu_configure_sensor(struct fcu_softc *sc, envsys_data_t *s)
    302 {
    303 	int have_eeprom1 = 1;
    304 
    305 	if (get_cpuid(1, sc->sc_eeprom1) < 160)
    306 		have_eeprom1 = 0;
    307 
    308 	if (s->units == ENVSYS_SFANRPM) {
    309 		fcu_fan_t *fan = &sc->sc_fans[sc->sc_nfans];
    310 		uint8_t *eeprom = NULL;
    311 		uint16_t rmin, rmax;
    312 
    313 		if (strstr(s->desc, "CPU A") != NULL)
    314 			eeprom = sc->sc_eeprom0;
    315 		if (strstr(s->desc, "CPU B") != NULL) {
    316 			/*
    317 			 * XXX
    318 			 * this should never happen
    319 			 */
    320 			if (have_eeprom1 == 0) {
    321 				eeprom = sc->sc_eeprom0;
    322 			} else
    323 				eeprom = sc->sc_eeprom1;
    324 		}
    325 
    326 		fan->reg = s->private;
    327 		fan->target = 0;
    328 		fan->duty = 0x80;
    329 
    330 		/* speed settings from EEPROM */
    331 		if (strstr(s->desc, "PUMP") != NULL) {
    332 			KASSERT(eeprom != NULL);
    333 			memcpy(&rmin, &eeprom[0x54], 2);
    334 			memcpy(&rmax, &eeprom[0x56], 2);
    335 			fan->base_rpm = rmin;
    336 			fan->max_rpm = rmax;
    337 			fan->step = (rmax - rmin) / 30;
    338 		} else if (strstr(s->desc, "INTAKE") != NULL) {
    339 			KASSERT(eeprom != NULL);
    340 			memcpy(&rmin, &eeprom[0x4c], 2);
    341 			memcpy(&rmax, &eeprom[0x4e], 2);
    342 			fan->base_rpm = rmin;
    343 			fan->max_rpm = rmax;
    344 			fan->step = (rmax - rmin) / 30;
    345 		} else if (strstr(s->desc, "EXHAUST") != NULL) {
    346 			KASSERT(eeprom != NULL);
    347 			memcpy(&rmin, &eeprom[0x50], 2);
    348 			memcpy(&rmax, &eeprom[0x52], 2);
    349 			fan->base_rpm = rmin;
    350 			fan->max_rpm = rmax;
    351 			fan->step = (rmax - rmin) / 30;
    352 		} else if (strstr(s->desc, "DRIVE") != NULL ) {
    353 			fan->base_rpm = 1000;
    354 			fan->max_rpm = 3000;
    355 			fan->step = 100;
    356 		} else {
    357 			fan->base_rpm = 1000;
    358 			fan->max_rpm = 3000;
    359 			fan->step = 100;
    360 		}
    361 		DPRINTF("fan %s: %d - %d rpm, step %d\n",
    362 		   s->desc, fan->base_rpm, fan->max_rpm, fan->step);
    363 
    364 		/* now stuff them into zones */
    365 		if (strstr(s->desc, "CPU") != NULL) {
    366 			fancontrol_zone_t *z = &sc->sc_zones[FCU_ZONE_CPU];
    367 			z->fans[z->nfans].num = sc->sc_nfans;
    368 			z->fans[z->nfans].min_rpm = fan->base_rpm;
    369 			z->fans[z->nfans].max_rpm = fan->max_rpm;
    370 			z->fans[z->nfans].name = s->desc;
    371 			z->nfans++;
    372 		} else if ((strstr(s->desc, "BACKSIDE") != NULL) ||
    373 			   (strstr(s->desc, "SLOT") != NULL))  {
    374 			fancontrol_zone_t *z = &sc->sc_zones[FCU_ZONE_CASE];
    375 			z->fans[z->nfans].num = sc->sc_nfans;
    376 			z->fans[z->nfans].min_rpm = fan->base_rpm;
    377 			z->fans[z->nfans].max_rpm = fan->max_rpm;
    378 			z->fans[z->nfans].name = s->desc;
    379 			z->nfans++;
    380 		} else if (strstr(s->desc, "DRIVE") != NULL) {
    381 			fancontrol_zone_t *z = &sc->sc_zones[FCU_ZONE_DRIVEBAY];
    382 			z->fans[z->nfans].num = sc->sc_nfans;
    383 			z->fans[z->nfans].min_rpm = fan->base_rpm;
    384 			z->fans[z->nfans].max_rpm = fan->max_rpm;
    385 			z->fans[z->nfans].name = s->desc;
    386 			z->nfans++;
    387 		}
    388 		sc->sc_nfans++;
    389 	}
    390 }
    391 static void
    392 fcu_sensors_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
    393 {
    394 	struct fcu_softc *sc = sme->sme_cookie;
    395 	uint8_t cmd;
    396 	uint16_t data = 0;
    397 	int error;
    398 
    399 	if (edata->units == ENVSYS_SFANRPM) {
    400 	    	cmd = edata->private + 1;
    401 	} else
    402 		cmd = edata->private;
    403 
    404 	/* fcu is a macppc only thing so we can safely assume big endian */
    405 	iic_acquire_bus(sc->sc_i2c, 0);
    406 	error = iic_exec(sc->sc_i2c, I2C_OP_READ_WITH_STOP,
    407 	    sc->sc_addr, &cmd, 1, &data, 2, 0);
    408 	iic_release_bus(sc->sc_i2c, 0);
    409 
    410 	if (error) {
    411 		edata->state = ENVSYS_SINVALID;
    412 		return;
    413 	}
    414 
    415 	edata->state = ENVSYS_SVALID;
    416 
    417 	switch (edata->units) {
    418 		case ENVSYS_SFANRPM:
    419 			edata->value_cur = data >> 3;
    420 			break;
    421 		case ENVSYS_SVOLTS_DC:
    422 			/* XXX this reads bogus */
    423 			edata->value_cur = data * 1000;
    424 			break;
    425 		case ENVSYS_INDICATOR:
    426 			/* guesswork for now */
    427 			edata->value_cur = data >> 8;
    428 			break;
    429 		default:
    430 			edata->state = ENVSYS_SINVALID;
    431 	}
    432 }
    433 
    434 static bool
    435 is_cpu(const envsys_data_t *edata)
    436 {
    437 	if (edata->units != ENVSYS_STEMP)
    438 		return false;
    439 	if (strstr(edata->desc, "CPU") != NULL)
    440 		return TRUE;
    441 	return false;
    442 }
    443 
    444 static bool
    445 is_case(const envsys_data_t *edata)
    446 {
    447 	if (edata->units != ENVSYS_STEMP)
    448 		return false;
    449 	if ((strstr(edata->desc, "MLB") != NULL) ||
    450 	    (strstr(edata->desc, "BACKSIDE") != NULL) ||
    451 	    (strstr(edata->desc, "U3") != NULL))
    452 		return TRUE;
    453 	return false;
    454 }
    455 
    456 static bool
    457 is_drive(const envsys_data_t *edata)
    458 {
    459 	if (edata->units != ENVSYS_STEMP)
    460 		return false;
    461 	if (strstr(edata->desc, "DRIVE") != NULL)
    462 		return TRUE;
    463 	return false;
    464 }
    465 
    466 static int
    467 fcu_get_rpm(void *cookie, int which)
    468 {
    469 	struct fcu_softc *sc = cookie;
    470 	fcu_fan_t *f = &sc->sc_fans[which];
    471 	int error;
    472 	uint16_t data = 0;
    473 	uint8_t cmd;
    474 
    475 	iic_acquire_bus(sc->sc_i2c, 0);
    476 	cmd = f->reg + 1;
    477 	error = iic_exec(sc->sc_i2c, I2C_OP_READ_WITH_STOP,
    478 	    sc->sc_addr, &cmd, 1, &data, 2, 0);
    479 	iic_release_bus(sc->sc_i2c, 0);
    480 	if (error != 0) return 0;
    481 	data = data >> 3;
    482 	return data;
    483 }
    484 
    485 static int
    486 fcu_set_rpm(void *cookie, int which, int speed)
    487 {
    488 	struct fcu_softc *sc = cookie;
    489 	fcu_fan_t *f = &sc->sc_fans[which];
    490 	int error = 0;
    491 	uint8_t cmd;
    492 
    493 	if (speed > f->max_rpm) speed = f->max_rpm;
    494 	if (speed < f->base_rpm) speed = f->base_rpm;
    495 
    496 	if (f->reg < 0x30) {
    497 		uint16_t data;
    498 		/* simple rpm fan, just poke the register */
    499 
    500 		if (f->target == speed) return 0;
    501 		iic_acquire_bus(sc->sc_i2c, 0);
    502 		cmd = f->reg;
    503 		data = (speed << 3);
    504 		error = iic_exec(sc->sc_i2c, I2C_OP_WRITE_WITH_STOP,
    505 		    sc->sc_addr, &cmd, 1, &data, 2, 0);
    506 		iic_release_bus(sc->sc_i2c, 0);
    507 	} else {
    508 		int diff;
    509 		int nduty = f->duty;
    510 		int current_speed;
    511 		/* pwm fan, measure speed, then adjust duty cycle */
    512 		DPRINTF("pwm fan ");
    513 		current_speed = fcu_get_rpm(sc, which);
    514 		diff = current_speed - speed;
    515 		DPRINTF("d %d s %d t %d diff %d ", f->duty, current_speed, speed, diff);
    516 		if (diff > 100) {
    517 			nduty = uimax(20, nduty - 1);
    518 		}
    519 		if (diff < -100) {
    520 			nduty = uimin(0xd0, nduty + 1);
    521 		}
    522 		cmd = f->reg;
    523 		DPRINTF("%s nduty %d", __func__, nduty);
    524 		if (nduty != f->duty) {
    525 			uint8_t arg = nduty;
    526 			iic_acquire_bus(sc->sc_i2c, 0);
    527 			error = iic_exec(sc->sc_i2c, I2C_OP_WRITE_WITH_STOP,
    528 			    sc->sc_addr, &cmd, 1, &arg, 1, 0);
    529 			iic_release_bus(sc->sc_i2c, 0);
    530 			f->duty = nduty;
    531 			sc->sc_pwm = TRUE;
    532 
    533 		}
    534 		DPRINTF("ok\n");
    535 	}
    536 	if (error) printf("boo\n");
    537 	f->target = speed;
    538 	return 0;
    539 }
    540 
    541 static void
    542 fcu_adjust(void *cookie)
    543 {
    544 	struct fcu_softc *sc = cookie;
    545 	int i;
    546 	uint8_t cmd, data;
    547 
    548 	while (!sc->sc_dying) {
    549 		/* poke the FCU so we don't go 747 */
    550 		iic_acquire_bus(sc->sc_i2c, 0);
    551 		cmd = FCU_FAN_ACTIVE;
    552 		iic_exec(sc->sc_i2c, I2C_OP_READ_WITH_STOP,
    553 		    sc->sc_addr, &cmd, 1, &data, 1, 0);
    554 		iic_release_bus(sc->sc_i2c, 0);
    555 		sc->sc_pwm = FALSE;
    556 		for (i = 0; i < FCU_ZONE_COUNT; i++)
    557 			fancontrol_adjust_zone(&sc->sc_zones[i]);
    558 		/*
    559 		 * take a shorter nap if we're in the process of adjusting a
    560 		 * PWM fan, which relies on measuring speed and then changing
    561 		 * its duty cycle until we're reasonable close to the target
    562 		 * speed
    563 		 */
    564 		kpause("fanctrl", true, mstohz(sc->sc_pwm ? 1000 : 2000), NULL);
    565 	}
    566 	kthread_exit(0);
    567 }
    568