xref: /netbsd-src/sys/dev/i2c/lm75.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*	$NetBSD: lm75.c,v 1.36 2020/08/21 20:41:43 macallan Exp $	*/
2 
3 /*
4  * Copyright (c) 2003 Wasabi Systems, Inc.
5  * All rights reserved.
6  *
7  * Written by 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: lm75.c,v 1.36 2020/08/21 20:41:43 macallan 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/sysctl.h>
46 
47 #include <dev/sysmon/sysmonvar.h>
48 
49 #include <dev/i2c/i2cvar.h>
50 #include <dev/i2c/lm75reg.h>
51 
52 struct lmtemp_softc {
53 	device_t sc_dev;
54 	i2c_tag_t sc_tag;
55 	int sc_address;
56 	prop_dictionary_t sc_prop;
57 
58 	struct sysmon_envsys *sc_sme;
59 	envsys_data_t sc_sensor;
60 	int sc_tmax;
61 	uint32_t sc_smax, sc_smin, sc_scrit;
62 
63 	uint32_t (*sc_lmtemp_decode)(const uint8_t *, int);
64 	void (*sc_lmtemp_encode)(const uint32_t, uint8_t *, int);
65 };
66 
67 static int  lmtemp_match(device_t, cfdata_t, void *);
68 static void lmtemp_attach(device_t, device_t, void *);
69 
70 CFATTACH_DECL_NEW(lmtemp, sizeof(struct lmtemp_softc),
71 	lmtemp_match, lmtemp_attach, NULL, NULL);
72 
73 static void	lmtemp_refresh(struct sysmon_envsys *, envsys_data_t *);
74 static int	lmtemp_config_write(struct lmtemp_softc *, uint8_t);
75 static int	lmtemp_temp_write(struct lmtemp_softc *, uint8_t, uint32_t,
76 				int);
77 static int	lmtemp_temp_read(struct lmtemp_softc *, uint8_t, uint32_t *,
78 				int);
79 static uint32_t lmtemp_decode_lm75(const uint8_t *, int);
80 static uint32_t lmtemp_decode_ds75(const uint8_t *, int);
81 static uint32_t lmtemp_decode_lm77(const uint8_t *, int);
82 static void	lmtemp_encode_lm75(const uint32_t, uint8_t *, int);
83 static void	lmtemp_encode_ds75(const uint32_t, uint8_t *, int);
84 static void	lmtemp_encode_lm77(const uint32_t, uint8_t *, int);
85 static void	lmtemp_getlim_lm75(struct sysmon_envsys *, envsys_data_t *,
86 				sysmon_envsys_lim_t *, uint32_t *);
87 static void	lmtemp_getlim_lm77(struct sysmon_envsys *, envsys_data_t *,
88 				sysmon_envsys_lim_t *, uint32_t *);
89 static void	lmtemp_setlim_lm75(struct sysmon_envsys *, envsys_data_t *,
90 				sysmon_envsys_lim_t *, uint32_t *);
91 static void	lmtemp_setlim_lm77(struct sysmon_envsys *, envsys_data_t *,
92 				sysmon_envsys_lim_t *, uint32_t *);
93 
94 static void	lmtemp_setup_sysctl(struct lmtemp_softc *);
95 static int	sysctl_lm75_temp(SYSCTLFN_ARGS);
96 
97 static const struct device_compatible_entry compat_data[] = {
98 	{ "i2c-lm75",			0 },
99 	{ "lm75",			0 },
100 	{ "ds1775",			0 },
101 	/*
102 	 * see XXX in _attach() below: add code once non-lm75 matches are
103 	 * added here!
104 	 */
105 	{ NULL,				0 }
106 };
107 
108 enum {
109 	lmtemp_lm75 = 0,
110 	lmtemp_ds75,
111 	lmtemp_lm77,
112 };
113 static const struct {
114 	int lmtemp_type;
115 	const char *lmtemp_name;
116 	int lmtemp_addrmask;
117 	int lmtemp_addr;
118 	uint32_t (*lmtemp_decode)(const uint8_t *, int);
119 	void (*lmtemp_encode)(const uint32_t, uint8_t *, int);
120 	void (*lmtemp_getlim)(struct sysmon_envsys *, envsys_data_t *,
121 		sysmon_envsys_lim_t *, uint32_t *);
122 	void (*lmtemp_setlim)(struct sysmon_envsys *, envsys_data_t *,
123 		sysmon_envsys_lim_t *, uint32_t *);
124 } lmtemptbl[] = {
125 	{ lmtemp_lm75,	"LM75",	LM75_ADDRMASK,	LM75_ADDR,
126 	    lmtemp_decode_lm75,	lmtemp_encode_lm75,
127 	    lmtemp_getlim_lm75,	lmtemp_setlim_lm75 },
128 	{ lmtemp_ds75,	"DS75",	LM75_ADDRMASK,	LM75_ADDR,
129 	    lmtemp_decode_ds75,	lmtemp_encode_ds75,
130 	    lmtemp_getlim_lm75,	lmtemp_setlim_lm75 },
131 	{ lmtemp_lm77,	"LM77",	LM77_ADDRMASK,	LM77_ADDR,
132 	    lmtemp_decode_lm77, lmtemp_encode_lm77,
133 	    lmtemp_getlim_lm77,	lmtemp_setlim_lm77 },
134 	{ -1,		NULL,	 0,		0,
135 	    NULL,		NULL,
136 	    NULL,		NULL }
137 };
138 
139 static int
140 lmtemp_match(device_t parent, cfdata_t cf, void *aux)
141 {
142 	struct i2c_attach_args *ia = aux;
143 	int i, match_result;
144 
145 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
146 		return match_result;
147 
148 	/*
149 	 * Indirect config - not much we can do!
150 	 */
151 	for (i = 0; lmtemptbl[i].lmtemp_type != -1 ; i++)
152 		if (lmtemptbl[i].lmtemp_type == cf->cf_flags)
153 			break;
154 	if (lmtemptbl[i].lmtemp_type == -1)
155 		return 0;
156 
157 	if ((ia->ia_addr & lmtemptbl[i].lmtemp_addrmask) ==
158 	    lmtemptbl[i].lmtemp_addr)
159 		return I2C_MATCH_ADDRESS_ONLY;
160 
161 	return 0;
162 }
163 
164 static void
165 lmtemp_attach(device_t parent, device_t self, void *aux)
166 {
167 	struct lmtemp_softc *sc = device_private(self);
168 	struct i2c_attach_args *ia = aux;
169 	char name[64];
170 	const char *desc;
171 	int i;
172 
173 	sc->sc_dev = self;
174 	if (ia->ia_name == NULL) {
175 		for (i = 0; lmtemptbl[i].lmtemp_type != -1 ; i++)
176 			if (lmtemptbl[i].lmtemp_type ==
177 			    device_cfdata(self)->cf_flags)
178 				break;
179 	} else {
180 		if (strcmp(ia->ia_name, "ds1775") == 0) {
181 			i = 1;	/* LMTYPE_DS75 */
182 		} else {
183 			/* XXX - add code when adding other direct matches! */
184 			i = 0;
185 		}
186 	}
187 
188 	sc->sc_tag = ia->ia_tag;
189 	sc->sc_address = ia->ia_addr;
190 	sc->sc_prop = ia->ia_prop;
191 
192 	aprint_naive(": Temperature Sensor\n");
193 	if (ia->ia_name) {
194 		aprint_normal(": %s %s Temperature Sensor\n", ia->ia_name,
195 			lmtemptbl[i].lmtemp_name);
196 	} else {
197 		aprint_normal(": %s Temperature Sensor\n",
198 			lmtemptbl[i].lmtemp_name);
199 	}
200 
201 	sc->sc_lmtemp_decode = lmtemptbl[i].lmtemp_decode;
202 	sc->sc_lmtemp_encode = lmtemptbl[i].lmtemp_encode;
203 
204 	iic_acquire_bus(sc->sc_tag, 0);
205 
206 	/* Read temperature limit(s) and remember initial value(s). */
207 	if (i == lmtemp_lm77) {
208 		if (lmtemp_temp_read(sc, LM77_REG_TCRIT_SET_POINT,
209 		    &sc->sc_scrit, 1) != 0) {
210 			aprint_error_dev(self,
211 			    "unable to read low register\n");
212 			iic_release_bus(sc->sc_tag, 0);
213 			return;
214 		}
215 		if (lmtemp_temp_read(sc, LM77_REG_TLOW_SET_POINT,
216 		    &sc->sc_smin, 1) != 0) {
217 			aprint_error_dev(self,
218 			    "unable to read low register\n");
219 			iic_release_bus(sc->sc_tag, 0);
220 			return;
221 		}
222 		if (lmtemp_temp_read(sc, LM77_REG_THIGH_SET_POINT,
223 		    &sc->sc_smax, 1) != 0) {
224 			aprint_error_dev(self,
225 			    "unable to read high register\n");
226 			iic_release_bus(sc->sc_tag, 0);
227 			return;
228 		}
229 	} else {	/* LM75 or compatible */
230 		if (lmtemp_temp_read(sc, LM75_REG_TOS_SET_POINT,
231 		    &sc->sc_smax, 1) != 0) {
232 			aprint_error_dev(self, "unable to read Tos register\n");
233 			iic_release_bus(sc->sc_tag, 0);
234 			return;
235 		}
236 	}
237 	sc->sc_tmax = sc->sc_smax;
238 
239 	if (i == lmtemp_lm75)
240 		lmtemp_setup_sysctl(sc);
241 
242 	/* Set the configuration of the LM75 to defaults. */
243 	if (lmtemp_config_write(sc, LM75_CONFIG_FAULT_QUEUE_4) != 0) {
244 		aprint_error_dev(self, "unable to write config register\n");
245 		iic_release_bus(sc->sc_tag, 0);
246 		return;
247 	}
248 	iic_release_bus(sc->sc_tag, 0);
249 
250 	sc->sc_sme = sysmon_envsys_create();
251 	/* Initialize sensor data. */
252 	sc->sc_sensor.units =  ENVSYS_STEMP;
253 	sc->sc_sensor.state =  ENVSYS_SINVALID;
254 	sc->sc_sensor.flags =  ENVSYS_FMONLIMITS;
255 
256 	(void)strlcpy(name,
257 	    ia->ia_name? ia->ia_name : device_xname(self),
258 	    sizeof(sc->sc_sensor.desc));
259 
260 	if (prop_dictionary_get_cstring_nocopy(sc->sc_prop, "s00", &desc)) {
261 		strncpy(name, desc, 64);
262 	}
263 
264 	(void)strlcpy(sc->sc_sensor.desc, name,
265 	    sizeof(sc->sc_sensor.desc));
266 	if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
267 		sysmon_envsys_destroy(sc->sc_sme);
268 		return;
269 	}
270 
271 	/* Hook into system monitor. */
272 	sc->sc_sme->sme_name = device_xname(self);
273 	sc->sc_sme->sme_cookie = sc;
274 	sc->sc_sme->sme_refresh = lmtemp_refresh;
275 	sc->sc_sme->sme_get_limits = lmtemptbl[i].lmtemp_getlim;
276 	sc->sc_sme->sme_set_limits = lmtemptbl[i].lmtemp_setlim;
277 
278 	if (sysmon_envsys_register(sc->sc_sme)) {
279 		aprint_error_dev(self, "unable to register with sysmon\n");
280 		sysmon_envsys_destroy(sc->sc_sme);
281 	}
282 }
283 
284 static int
285 lmtemp_config_write(struct lmtemp_softc *sc, uint8_t val)
286 {
287 	uint8_t cmdbuf[2];
288 
289 	cmdbuf[0] = LM75_REG_CONFIG;
290 	cmdbuf[1] = val;
291 
292 	return iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
293 	    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0);
294 }
295 
296 static int
297 lmtemp_temp_write(struct lmtemp_softc *sc, uint8_t reg, uint32_t val, int degc)
298 {
299 	uint8_t cmdbuf[3];
300 
301 	cmdbuf[0] = reg;
302 	sc->sc_lmtemp_encode(val, &cmdbuf[1], degc);
303 
304 	return iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
305 	    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 2, 0);
306 }
307 
308 static int
309 lmtemp_temp_read(struct lmtemp_softc *sc, uint8_t which, uint32_t *valp,
310     int degc)
311 {
312 	int error;
313 	uint8_t cmdbuf[1];
314 	uint8_t buf[LM75_TEMP_LEN];
315 
316 	cmdbuf[0] = which;
317 
318 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
319 	    sc->sc_address, cmdbuf, 1, buf, LM75_TEMP_LEN, 0);
320 	if (error)
321 		return error;
322 
323 	*valp = sc->sc_lmtemp_decode(buf, degc);
324 	return 0;
325 }
326 
327 static void
328 lmtemp_refresh_sensor_data(struct lmtemp_softc *sc)
329 {
330 	uint32_t val;
331 	int error;
332 
333 	error = lmtemp_temp_read(sc, LM75_REG_TEMP, &val, 0);
334 	if (error) {
335 #if 0
336 		aprint_error_dev(sc->sc_dev, "unable to read temperature, error = %d\n",
337 		    error);
338 #endif
339 		sc->sc_sensor.state = ENVSYS_SINVALID;
340 		return;
341 	}
342 
343 	sc->sc_sensor.value_cur = val;
344 	sc->sc_sensor.state = ENVSYS_SVALID;
345 }
346 
347 static void
348 lmtemp_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
349 {
350 	struct lmtemp_softc *sc = sme->sme_cookie;
351 
352 	iic_acquire_bus(sc->sc_tag, 0);	/* also locks our instance */
353 	lmtemp_refresh_sensor_data(sc);
354 	iic_release_bus(sc->sc_tag, 0);	/* also unlocks our instance */
355 }
356 
357 static void
358 lmtemp_getlim_lm75(struct sysmon_envsys *sme, envsys_data_t *edata,
359     sysmon_envsys_lim_t *limits, uint32_t *props)
360 {
361 	struct lmtemp_softc *sc = sme->sme_cookie;
362 	uint32_t val;
363 
364 	*props &= ~(PROP_CRITMAX);
365 
366 	iic_acquire_bus(sc->sc_tag, 0);
367 	if (lmtemp_temp_read(sc, LM75_REG_TOS_SET_POINT, &val, 0) == 0) {
368 		limits->sel_critmax = val;
369 		*props |= PROP_CRITMAX;
370 	}
371 	iic_release_bus(sc->sc_tag, 0);
372 }
373 
374 static void
375 lmtemp_getlim_lm77(struct sysmon_envsys *sme, envsys_data_t *edata,
376     sysmon_envsys_lim_t *limits, uint32_t *props)
377 {
378 	struct lmtemp_softc *sc = sme->sme_cookie;
379 	uint32_t val;
380 
381 	*props &= ~(PROP_CRITMAX | PROP_WARNMAX | PROP_WARNMIN);
382 
383 	iic_acquire_bus(sc->sc_tag, 0);
384 	if (lmtemp_temp_read(sc, LM77_REG_TCRIT_SET_POINT, &val, 0) == 0) {
385 		limits->sel_critmax = val;
386 		*props |= PROP_CRITMAX;
387 	}
388 	if (lmtemp_temp_read(sc, LM77_REG_THIGH_SET_POINT, &val, 0) == 0) {
389 		limits->sel_warnmax = val;
390 		*props |= PROP_WARNMAX;
391 	}
392 	if (lmtemp_temp_read(sc, LM77_REG_TLOW_SET_POINT, &val, 0) == 0) {
393 		limits->sel_warnmin = val;
394 		*props |= PROP_WARNMIN;
395 	}
396 	iic_release_bus(sc->sc_tag, 0);
397 }
398 
399 static void
400 lmtemp_setlim_lm75(struct sysmon_envsys *sme, envsys_data_t *edata,
401     sysmon_envsys_lim_t *limits, uint32_t *props)
402 {
403 	struct lmtemp_softc *sc = sme->sme_cookie;
404 	int32_t limit;
405 
406 	if (*props & PROP_CRITMAX) {
407 		if (limits == NULL)	/* Restore defaults */
408 			limit = sc->sc_smax;
409 		else
410 			limit = limits->sel_critmax;
411 		iic_acquire_bus(sc->sc_tag, 0);
412 		lmtemp_temp_write(sc, LM75_REG_THYST_SET_POINT,
413 		    limit - 5000000, 0);
414 		lmtemp_temp_write(sc, LM75_REG_TOS_SET_POINT, limit, 0);
415 		iic_release_bus(sc->sc_tag, 0);
416 
417 		/* Synchronise sysctl */
418 		sc->sc_tmax = (limit - 273150000) / 1000000;
419 	}
420 }
421 
422 static void
423 lmtemp_setlim_lm77(struct sysmon_envsys *sme, envsys_data_t *edata,
424     sysmon_envsys_lim_t *limits, uint32_t *props)
425 {
426 	struct lmtemp_softc *sc = sme->sme_cookie;
427 	int32_t limit;
428 
429 	iic_acquire_bus(sc->sc_tag, 0);
430 	if (*props & PROP_CRITMAX) {
431 		if (limits == NULL)	/* Restore defaults */
432 			limit = sc->sc_scrit;
433 		else
434 			limit = limits->sel_critmax;
435 		lmtemp_temp_write(sc, LM77_REG_TCRIT_SET_POINT, limit, 0);
436 	}
437 	if (*props & PROP_WARNMAX) {
438 		if (limits == NULL)	/* Restore defaults */
439 			limit = sc->sc_smax;
440 		else
441 			limit = limits->sel_warnmax;
442 		lmtemp_temp_write(sc, LM77_REG_THIGH_SET_POINT, limit, 0);
443 	}
444 	if (*props & PROP_WARNMIN) {
445 		if (limits == NULL)	/* Restore defaults */
446 			limit = sc->sc_smin;
447 		else
448 			limit = limits->sel_warnmin;
449 		lmtemp_temp_write(sc, LM77_REG_TLOW_SET_POINT, limit, 0);
450 	}
451 	iic_release_bus(sc->sc_tag, 0);
452 }
453 
454 static uint32_t
455 lmtemp_decode_lm75(const uint8_t *buf, int degc)
456 {
457 	int temp;
458 	uint32_t val;
459 
460 	/*
461 	 * LM75 temps are the most-significant 9 bits of a 16-bit reg.
462 	 * sign-extend the MSB and add in the 0.5 from the LSB
463 	 */
464 	temp = (int8_t) buf[0];
465 	temp = (temp << 1) + ((buf[1] >> 7) & 0x1);
466 
467 	/* Temp is given in 1/2 deg. C, we convert to C or uK. */
468 	if (degc)
469 		val = temp / 2;
470 	else
471 		val = temp * 500000 + 273150000;
472 
473 	return val;
474 }
475 
476 static uint32_t
477 lmtemp_decode_ds75(const uint8_t *buf, int degc)
478 {
479 	int temp;
480 
481 	/*
482 	 * Sign-extend the MSB byte, and add in the fractions of a
483 	 * degree contained in the LSB (precision 1/16th DegC).
484 	 */
485 	temp = (int8_t)buf[0];
486 	temp = (temp << 4) | ((buf[1] >> 4) & 0xf);
487 
488 	/*
489 	 * Conversion to C or uK is simple.
490 	 */
491 	if (degc)
492 		return temp / 16;
493 	else
494 		return (temp * 62500 + 273150000);
495 }
496 
497 static uint32_t
498 lmtemp_decode_lm77(const uint8_t *buf, int degc)
499 {
500 	int temp;
501 	uint32_t val;
502 
503 	/*
504 	 * Describe each bits of temperature registers on LM77.
505 	 *   D15 - D12:	Sign
506 	 *   D11 - D3 :	Bit8(MSB) - Bit0
507 	 */
508 	temp = (int8_t)buf[0];
509 	temp = (temp << 5) | ((buf[1] >> 3) & 0x1f);
510 
511 	/* Temp is given in 1/2 deg. C, we convert to C or uK. */
512 	if (degc)
513 		val = temp / 2;
514 	else
515 		val = temp * 500000 + 273150000;
516 
517 	return val;
518 }
519 
520 static void lmtemp_encode_lm75(const uint32_t val, uint8_t *buf, int degc)
521 {
522 	int temp;
523 
524 	/* Convert from C or uK to register format */
525 	if (degc)
526 		temp = val * 2;
527 	else
528 		temp = (val - 273150000) / 500000;
529 	buf[0] = (temp >> 1) & 0xff;
530 	buf[1] = (temp & 1) << 7;
531 }
532 
533 static void lmtemp_encode_ds75(const uint32_t val, uint8_t *buf, int degc)
534 {
535 	int temp;
536 
537 	/* Convert from C or uK to register format */
538 	if (degc)
539 		temp = val * 16;
540 	else
541 		temp = (val - 273150000) / 62500;
542 	buf[0] = (temp >> 4) & 0xff;
543 	buf[1] = (temp & 0xf) << 4;
544 }
545 
546 static void lmtemp_encode_lm77(const uint32_t val, uint8_t *buf, int degc)
547 {
548 	int temp;
549 
550 	/* Convert from C or uK to register format */
551 	if (degc)
552 		temp = val * 2;
553 	else
554 		temp = (val - 273150000) / 500000;
555 	buf[0] = (temp >> 5) & 0xff;
556 	buf[1] = (temp & 0x1f) << 3;
557 }
558 
559 static void
560 lmtemp_setup_sysctl(struct lmtemp_softc *sc)
561 {
562 	const struct sysctlnode *me = NULL, *node = NULL;
563 
564 	sysctl_createv(NULL, 0, NULL, &me,
565 	    CTLFLAG_READWRITE,
566 	    CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
567 	    NULL, 0, NULL, 0,
568 	    CTL_MACHDEP, CTL_CREATE, CTL_EOL);
569 
570 	sysctl_createv(NULL, 0, NULL, &node,
571 	    CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
572 	    CTLTYPE_INT, "temp", "Threshold temperature",
573 	    sysctl_lm75_temp, 1, (void *)sc, 0,
574 	    CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);
575 }
576 
577 static int
578 sysctl_lm75_temp(SYSCTLFN_ARGS)
579 {
580 	struct sysctlnode node = *rnode;
581 	struct lmtemp_softc *sc = node.sysctl_data;
582 	int temp;
583 
584 	if (newp) {
585 
586 		/* we're asked to write */
587 		node.sysctl_data = &sc->sc_tmax;
588 		if (sysctl_lookup(SYSCTLFN_CALL(&node)) == 0) {
589 
590 			temp = *(int *)node.sysctl_data;
591 			sc->sc_tmax = temp;
592 			iic_acquire_bus(sc->sc_tag, 0);
593 			lmtemp_temp_write(sc, LM75_REG_THYST_SET_POINT,
594 			    sc->sc_tmax - 5, 1);
595 			lmtemp_temp_write(sc, LM75_REG_TOS_SET_POINT,
596 			    sc->sc_tmax, 1);
597 			iic_release_bus(sc->sc_tag, 0);
598 
599 			/* Synchronise envsys - calls lmtemp_getlim_lm75() */
600 			sysmon_envsys_update_limits(sc->sc_sme, &sc->sc_sensor);
601 			return 0;
602 		}
603 		return EINVAL;
604 	} else {
605 
606 		node.sysctl_data = &sc->sc_tmax;
607 		node.sysctl_size = 4;
608 		return (sysctl_lookup(SYSCTLFN_CALL(&node)));
609 	}
610 
611 	return 0;
612 }
613 
614 SYSCTL_SETUP(sysctl_lmtemp_setup, "sysctl lmtemp subtree setup")
615 {
616 
617 	sysctl_createv(NULL, 0, NULL, NULL,
618 		       CTLFLAG_PERMANENT,
619 		       CTLTYPE_NODE, "machdep", NULL,
620 		       NULL, 0, NULL, 0,
621 		       CTL_MACHDEP, CTL_EOL);
622 }
623 
624 
625