xref: /netbsd-src/sys/dev/i2c/lm75.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /*	$NetBSD: lm75.c,v 1.43 2021/05/21 20:42:05 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 1.43 2021/05/21 20:42:05 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 enum {
98 	lmtemp_lm75 = 0,
99 	lmtemp_ds75 = 1,
100 	lmtemp_lm77 = 2,
101 };
102 
103 static const struct device_compatible_entry compat_data[] = {
104 	{ .compat = "national,lm75",	.value = lmtemp_lm75 },
105 	{ .compat = "i2c-lm75",		.value = lmtemp_lm75 },
106 	{ .compat = "lm75",		.value = lmtemp_lm75 },
107 
108 	/* XXX Linux treats ds1775 and ds75 differently. */
109 	{ .compat = "dallas,ds1775",	.value = lmtemp_ds75 },
110 	{ .compat = "ds1775",		.value = lmtemp_ds75 },
111 
112 	{ .compat = "national,lm77",	.value = lmtemp_lm77 },
113 
114 	/*
115 	 * see XXX in _attach() below: add code once non-lm75 matches are
116 	 * added here!
117 	 */
118 	DEVICE_COMPAT_EOL
119 };
120 
121 static const struct {
122 	const char *lmtemp_name;
123 	int lmtemp_addrmask;
124 	int lmtemp_addr;
125 	uint32_t (*lmtemp_decode)(const uint8_t *, int);
126 	void (*lmtemp_encode)(const uint32_t, uint8_t *, int);
127 	void (*lmtemp_getlim)(struct sysmon_envsys *, envsys_data_t *,
128 		sysmon_envsys_lim_t *, uint32_t *);
129 	void (*lmtemp_setlim)(struct sysmon_envsys *, envsys_data_t *,
130 		sysmon_envsys_lim_t *, uint32_t *);
131 } lmtemptbl[] = {
132 [lmtemp_lm75] =
133 	{
134 		.lmtemp_name = "LM75",
135 		.lmtemp_addrmask = LM75_ADDRMASK,
136 		.lmtemp_addr = LM75_ADDR,
137 		.lmtemp_decode = lmtemp_decode_lm75,
138 		.lmtemp_encode = lmtemp_encode_lm75,
139 		.lmtemp_getlim = lmtemp_getlim_lm75,
140 		.lmtemp_setlim = lmtemp_setlim_lm75,
141 	},
142 [lmtemp_ds75] =
143 	{
144 		.lmtemp_name = "DS75",
145 		.lmtemp_addrmask = LM75_ADDRMASK,
146 		.lmtemp_addr = LM75_ADDR,
147 		.lmtemp_decode = lmtemp_decode_ds75,
148 		.lmtemp_encode = lmtemp_encode_ds75,
149 		.lmtemp_getlim = lmtemp_getlim_lm75,
150 		.lmtemp_setlim = lmtemp_setlim_lm75,
151 	},
152 [lmtemp_lm77] =
153 	{
154 		.lmtemp_name = "LM77",
155 		.lmtemp_addrmask = LM77_ADDRMASK,
156 		.lmtemp_addr = LM77_ADDR,
157 		.lmtemp_decode = lmtemp_decode_lm77,
158 		.lmtemp_encode = lmtemp_encode_lm77,
159 		.lmtemp_getlim = lmtemp_getlim_lm77,
160 		.lmtemp_setlim = lmtemp_setlim_lm77,
161 	},
162 };
163 
164 static int
165 lmtemp_match(device_t parent, cfdata_t cf, void *aux)
166 {
167 	struct i2c_attach_args *ia = aux;
168 	int i, match_result;
169 
170 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
171 		return match_result;
172 
173 	/*
174 	 * Indirect config - not much we can do!
175 	 */
176 	for (i = 0; i < __arraycount(lmtemptbl); i++) {
177 		if (i == cf->cf_flags) {
178 			break;
179 		}
180 	}
181 	if (i == __arraycount(lmtemptbl)) {
182 		return 0;
183 	}
184 
185 	if ((ia->ia_addr & lmtemptbl[i].lmtemp_addrmask) ==
186 	    lmtemptbl[i].lmtemp_addr)
187 		return I2C_MATCH_ADDRESS_ONLY;
188 
189 	return 0;
190 }
191 
192 static void
193 lmtemp_attach(device_t parent, device_t self, void *aux)
194 {
195 	struct lmtemp_softc *sc = device_private(self);
196 	struct i2c_attach_args *ia = aux;
197 	const struct device_compatible_entry *dce;
198 	char name[64];
199 	const char *desc;
200 	int i;
201 
202 	sc->sc_dev = self;
203 	dce = iic_compatible_lookup(ia, compat_data);
204 	if (dce != NULL) {
205 		i = (int)dce->value;
206 	} else {
207 		for (i = 0; i < __arraycount(lmtemptbl); i++) {
208 			if (i == device_cfdata(self)->cf_flags) {
209 				break;
210 			}
211 		}
212 		KASSERT(i < __arraycount(lmtemptbl));
213 	}
214 
215 	sc->sc_tag = ia->ia_tag;
216 	sc->sc_address = ia->ia_addr;
217 	sc->sc_prop = ia->ia_prop;
218 
219 	if (ia->ia_prop != NULL) prop_object_retain(sc->sc_prop);
220 
221 	aprint_naive(": Temperature Sensor\n");
222 	if (ia->ia_name) {
223 		aprint_normal(": %s %s Temperature Sensor\n", ia->ia_name,
224 			lmtemptbl[i].lmtemp_name);
225 	} else {
226 		aprint_normal(": %s Temperature Sensor\n",
227 			lmtemptbl[i].lmtemp_name);
228 	}
229 
230 	sc->sc_lmtemp_decode = lmtemptbl[i].lmtemp_decode;
231 	sc->sc_lmtemp_encode = lmtemptbl[i].lmtemp_encode;
232 
233 	iic_acquire_bus(sc->sc_tag, 0);
234 
235 	/* Read temperature limit(s) and remember initial value(s). */
236 	if (i == lmtemp_lm77) {
237 		if (lmtemp_temp_read(sc, LM77_REG_TCRIT_SET_POINT,
238 		    &sc->sc_scrit, 1) != 0) {
239 			aprint_error_dev(self,
240 			    "unable to read low register\n");
241 			iic_release_bus(sc->sc_tag, 0);
242 			return;
243 		}
244 		if (lmtemp_temp_read(sc, LM77_REG_TLOW_SET_POINT,
245 		    &sc->sc_smin, 1) != 0) {
246 			aprint_error_dev(self,
247 			    "unable to read low register\n");
248 			iic_release_bus(sc->sc_tag, 0);
249 			return;
250 		}
251 		if (lmtemp_temp_read(sc, LM77_REG_THIGH_SET_POINT,
252 		    &sc->sc_smax, 1) != 0) {
253 			aprint_error_dev(self,
254 			    "unable to read high register\n");
255 			iic_release_bus(sc->sc_tag, 0);
256 			return;
257 		}
258 	} else {	/* LM75 or compatible */
259 		if (lmtemp_temp_read(sc, LM75_REG_TOS_SET_POINT,
260 		    &sc->sc_smax, 1) != 0) {
261 			aprint_error_dev(self, "unable to read Tos register\n");
262 			iic_release_bus(sc->sc_tag, 0);
263 			return;
264 		}
265 	}
266 	sc->sc_tmax = sc->sc_smax;
267 
268 	if (i == lmtemp_lm75)
269 		lmtemp_setup_sysctl(sc);
270 
271 	/* Set the configuration of the LM75 to defaults. */
272 	if (lmtemp_config_write(sc, LM75_CONFIG_FAULT_QUEUE_4) != 0) {
273 		aprint_error_dev(self, "unable to write config register\n");
274 		iic_release_bus(sc->sc_tag, 0);
275 		return;
276 	}
277 	iic_release_bus(sc->sc_tag, 0);
278 
279 	sc->sc_sme = sysmon_envsys_create();
280 	/* Initialize sensor data. */
281 	sc->sc_sensor.units =  ENVSYS_STEMP;
282 	sc->sc_sensor.state =  ENVSYS_SINVALID;
283 	sc->sc_sensor.flags =  ENVSYS_FMONLIMITS | ENVSYS_FHAS_ENTROPY;
284 
285 	(void)strlcpy(name,
286 	    ia->ia_name? ia->ia_name : device_xname(self),
287 	    sizeof(sc->sc_sensor.desc));
288 
289 	if (prop_dictionary_get_cstring_nocopy(sc->sc_prop, "s00", &desc)) {
290 		strncpy(name, desc, 64);
291 	}
292 
293 	(void)strlcpy(sc->sc_sensor.desc, name,
294 	    sizeof(sc->sc_sensor.desc));
295 	if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
296 		sysmon_envsys_destroy(sc->sc_sme);
297 		return;
298 	}
299 
300 	/* Hook into system monitor. */
301 	sc->sc_sme->sme_name = device_xname(self);
302 	sc->sc_sme->sme_cookie = sc;
303 	sc->sc_sme->sme_refresh = lmtemp_refresh;
304 	sc->sc_sme->sme_get_limits = lmtemptbl[i].lmtemp_getlim;
305 	sc->sc_sme->sme_set_limits = lmtemptbl[i].lmtemp_setlim;
306 
307 	if (sysmon_envsys_register(sc->sc_sme)) {
308 		aprint_error_dev(self, "unable to register with sysmon\n");
309 		sysmon_envsys_destroy(sc->sc_sme);
310 	}
311 }
312 
313 static int
314 lmtemp_config_write(struct lmtemp_softc *sc, uint8_t val)
315 {
316 	uint8_t cmdbuf[2];
317 
318 	cmdbuf[0] = LM75_REG_CONFIG;
319 	cmdbuf[1] = val;
320 
321 	return iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
322 	    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0);
323 }
324 
325 static int
326 lmtemp_temp_write(struct lmtemp_softc *sc, uint8_t reg, uint32_t val, int degc)
327 {
328 	uint8_t cmdbuf[3];
329 
330 	cmdbuf[0] = reg;
331 	sc->sc_lmtemp_encode(val, &cmdbuf[1], degc);
332 
333 	return iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP,
334 	    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 2, 0);
335 }
336 
337 static int
338 lmtemp_temp_read(struct lmtemp_softc *sc, uint8_t which, uint32_t *valp,
339     int degc)
340 {
341 	int error;
342 	uint8_t cmdbuf[1];
343 	uint8_t buf[LM75_TEMP_LEN];
344 
345 	cmdbuf[0] = which;
346 
347 	error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
348 	    sc->sc_address, cmdbuf, 1, buf, LM75_TEMP_LEN, 0);
349 	if (error)
350 		return error;
351 
352 	*valp = sc->sc_lmtemp_decode(buf, degc);
353 	return 0;
354 }
355 
356 static void
357 lmtemp_refresh_sensor_data(struct lmtemp_softc *sc)
358 {
359 	uint32_t val;
360 	int error;
361 
362 	error = lmtemp_temp_read(sc, LM75_REG_TEMP, &val, 0);
363 	if (error) {
364 #if 0
365 		aprint_error_dev(sc->sc_dev, "unable to read temperature, error = %d\n",
366 		    error);
367 #endif
368 		sc->sc_sensor.state = ENVSYS_SINVALID;
369 		return;
370 	}
371 
372 	sc->sc_sensor.value_cur = val;
373 	sc->sc_sensor.state = ENVSYS_SVALID;
374 }
375 
376 static void
377 lmtemp_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
378 {
379 	struct lmtemp_softc *sc = sme->sme_cookie;
380 
381 	iic_acquire_bus(sc->sc_tag, 0);	/* also locks our instance */
382 	lmtemp_refresh_sensor_data(sc);
383 	iic_release_bus(sc->sc_tag, 0);	/* also unlocks our instance */
384 }
385 
386 static void
387 lmtemp_getlim_lm75(struct sysmon_envsys *sme, envsys_data_t *edata,
388     sysmon_envsys_lim_t *limits, uint32_t *props)
389 {
390 	struct lmtemp_softc *sc = sme->sme_cookie;
391 	uint32_t val;
392 
393 	*props &= ~(PROP_CRITMAX);
394 
395 	iic_acquire_bus(sc->sc_tag, 0);
396 	if (lmtemp_temp_read(sc, LM75_REG_TOS_SET_POINT, &val, 0) == 0) {
397 		limits->sel_critmax = val;
398 		*props |= PROP_CRITMAX;
399 	}
400 	iic_release_bus(sc->sc_tag, 0);
401 }
402 
403 static void
404 lmtemp_getlim_lm77(struct sysmon_envsys *sme, envsys_data_t *edata,
405     sysmon_envsys_lim_t *limits, uint32_t *props)
406 {
407 	struct lmtemp_softc *sc = sme->sme_cookie;
408 	uint32_t val;
409 
410 	*props &= ~(PROP_CRITMAX | PROP_WARNMAX | PROP_WARNMIN);
411 
412 	iic_acquire_bus(sc->sc_tag, 0);
413 	if (lmtemp_temp_read(sc, LM77_REG_TCRIT_SET_POINT, &val, 0) == 0) {
414 		limits->sel_critmax = val;
415 		*props |= PROP_CRITMAX;
416 	}
417 	if (lmtemp_temp_read(sc, LM77_REG_THIGH_SET_POINT, &val, 0) == 0) {
418 		limits->sel_warnmax = val;
419 		*props |= PROP_WARNMAX;
420 	}
421 	if (lmtemp_temp_read(sc, LM77_REG_TLOW_SET_POINT, &val, 0) == 0) {
422 		limits->sel_warnmin = val;
423 		*props |= PROP_WARNMIN;
424 	}
425 	iic_release_bus(sc->sc_tag, 0);
426 }
427 
428 static void
429 lmtemp_setlim_lm75(struct sysmon_envsys *sme, envsys_data_t *edata,
430     sysmon_envsys_lim_t *limits, uint32_t *props)
431 {
432 	struct lmtemp_softc *sc = sme->sme_cookie;
433 	int32_t limit;
434 
435 	if (*props & PROP_CRITMAX) {
436 		if (limits == NULL)	/* Restore defaults */
437 			limit = sc->sc_smax;
438 		else
439 			limit = limits->sel_critmax;
440 		iic_acquire_bus(sc->sc_tag, 0);
441 		lmtemp_temp_write(sc, LM75_REG_THYST_SET_POINT,
442 		    limit - 5000000, 0);
443 		lmtemp_temp_write(sc, LM75_REG_TOS_SET_POINT, limit, 0);
444 		iic_release_bus(sc->sc_tag, 0);
445 
446 		/* Synchronise sysctl */
447 		sc->sc_tmax = (limit - 273150000) / 1000000;
448 	}
449 }
450 
451 static void
452 lmtemp_setlim_lm77(struct sysmon_envsys *sme, envsys_data_t *edata,
453     sysmon_envsys_lim_t *limits, uint32_t *props)
454 {
455 	struct lmtemp_softc *sc = sme->sme_cookie;
456 	int32_t limit;
457 
458 	iic_acquire_bus(sc->sc_tag, 0);
459 	if (*props & PROP_CRITMAX) {
460 		if (limits == NULL)	/* Restore defaults */
461 			limit = sc->sc_scrit;
462 		else
463 			limit = limits->sel_critmax;
464 		lmtemp_temp_write(sc, LM77_REG_TCRIT_SET_POINT, limit, 0);
465 	}
466 	if (*props & PROP_WARNMAX) {
467 		if (limits == NULL)	/* Restore defaults */
468 			limit = sc->sc_smax;
469 		else
470 			limit = limits->sel_warnmax;
471 		lmtemp_temp_write(sc, LM77_REG_THIGH_SET_POINT, limit, 0);
472 	}
473 	if (*props & PROP_WARNMIN) {
474 		if (limits == NULL)	/* Restore defaults */
475 			limit = sc->sc_smin;
476 		else
477 			limit = limits->sel_warnmin;
478 		lmtemp_temp_write(sc, LM77_REG_TLOW_SET_POINT, limit, 0);
479 	}
480 	iic_release_bus(sc->sc_tag, 0);
481 }
482 
483 static uint32_t
484 lmtemp_decode_lm75(const uint8_t *buf, int degc)
485 {
486 	int temp;
487 	uint32_t val;
488 
489 	/*
490 	 * LM75 temps are the most-significant 9 bits of a 16-bit reg.
491 	 * sign-extend the MSB and add in the 0.5 from the LSB
492 	 */
493 	temp = (int8_t) buf[0];
494 	temp = (temp << 1) + ((buf[1] >> 7) & 0x1);
495 
496 	/* Temp is given in 1/2 deg. C, we convert to C or uK. */
497 	if (degc)
498 		val = temp / 2;
499 	else
500 		val = temp * 500000 + 273150000;
501 
502 	return val;
503 }
504 
505 static uint32_t
506 lmtemp_decode_ds75(const uint8_t *buf, int degc)
507 {
508 	int temp;
509 
510 	/*
511 	 * Sign-extend the MSB byte, and add in the fractions of a
512 	 * degree contained in the LSB (precision 1/16th DegC).
513 	 */
514 	temp = (int8_t)buf[0];
515 	temp = (temp << 4) | ((buf[1] >> 4) & 0xf);
516 
517 	/*
518 	 * Conversion to C or uK is simple.
519 	 */
520 	if (degc)
521 		return temp / 16;
522 	else
523 		return (temp * 62500 + 273150000);
524 }
525 
526 static uint32_t
527 lmtemp_decode_lm77(const uint8_t *buf, int degc)
528 {
529 	int temp;
530 	uint32_t val;
531 
532 	/*
533 	 * Describe each bits of temperature registers on LM77.
534 	 *   D15 - D12:	Sign
535 	 *   D11 - D3 :	Bit8(MSB) - Bit0
536 	 */
537 	temp = (int8_t)buf[0];
538 	temp = (temp << 5) | ((buf[1] >> 3) & 0x1f);
539 
540 	/* Temp is given in 1/2 deg. C, we convert to C or uK. */
541 	if (degc)
542 		val = temp / 2;
543 	else
544 		val = temp * 500000 + 273150000;
545 
546 	return val;
547 }
548 
549 static void lmtemp_encode_lm75(const uint32_t val, uint8_t *buf, int degc)
550 {
551 	int temp;
552 
553 	/* Convert from C or uK to register format */
554 	if (degc)
555 		temp = val * 2;
556 	else
557 		temp = (val - 273150000) / 500000;
558 	buf[0] = (temp >> 1) & 0xff;
559 	buf[1] = (temp & 1) << 7;
560 }
561 
562 static void lmtemp_encode_ds75(const uint32_t val, uint8_t *buf, int degc)
563 {
564 	int temp;
565 
566 	/* Convert from C or uK to register format */
567 	if (degc)
568 		temp = val * 16;
569 	else
570 		temp = (val - 273150000) / 62500;
571 	buf[0] = (temp >> 4) & 0xff;
572 	buf[1] = (temp & 0xf) << 4;
573 }
574 
575 static void lmtemp_encode_lm77(const uint32_t val, uint8_t *buf, int degc)
576 {
577 	int temp;
578 
579 	/* Convert from C or uK to register format */
580 	if (degc)
581 		temp = val * 2;
582 	else
583 		temp = (val - 273150000) / 500000;
584 	buf[0] = (temp >> 5) & 0xff;
585 	buf[1] = (temp & 0x1f) << 3;
586 }
587 
588 static void
589 lmtemp_setup_sysctl(struct lmtemp_softc *sc)
590 {
591 	const struct sysctlnode *me = NULL, *node = NULL;
592 
593 	sysctl_createv(NULL, 0, NULL, &me,
594 	    CTLFLAG_READWRITE,
595 	    CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
596 	    NULL, 0, NULL, 0,
597 	    CTL_MACHDEP, CTL_CREATE, CTL_EOL);
598 
599 	sysctl_createv(NULL, 0, NULL, &node,
600 	    CTLFLAG_READWRITE | CTLFLAG_OWNDESC,
601 	    CTLTYPE_INT, "temp", "Threshold temperature",
602 	    sysctl_lm75_temp, 1, (void *)sc, 0,
603 	    CTL_MACHDEP, me->sysctl_num, CTL_CREATE, CTL_EOL);
604 }
605 
606 static int
607 sysctl_lm75_temp(SYSCTLFN_ARGS)
608 {
609 	struct sysctlnode node = *rnode;
610 	struct lmtemp_softc *sc = node.sysctl_data;
611 	int temp;
612 
613 	if (newp) {
614 
615 		/* we're asked to write */
616 		node.sysctl_data = &sc->sc_tmax;
617 		if (sysctl_lookup(SYSCTLFN_CALL(&node)) == 0) {
618 
619 			temp = *(int *)node.sysctl_data;
620 			sc->sc_tmax = temp;
621 			iic_acquire_bus(sc->sc_tag, 0);
622 			lmtemp_temp_write(sc, LM75_REG_THYST_SET_POINT,
623 			    sc->sc_tmax - 5, 1);
624 			lmtemp_temp_write(sc, LM75_REG_TOS_SET_POINT,
625 			    sc->sc_tmax, 1);
626 			iic_release_bus(sc->sc_tag, 0);
627 
628 			/* Synchronise envsys - calls lmtemp_getlim_lm75() */
629 			sysmon_envsys_update_limits(sc->sc_sme, &sc->sc_sensor);
630 			return 0;
631 		}
632 		return EINVAL;
633 	} else {
634 
635 		node.sysctl_data = &sc->sc_tmax;
636 		node.sysctl_size = 4;
637 		return (sysctl_lookup(SYSCTLFN_CALL(&node)));
638 	}
639 
640 	return 0;
641 }
642 
643 SYSCTL_SETUP(sysctl_lmtemp_setup, "sysctl lmtemp subtree setup")
644 {
645 
646 	sysctl_createv(NULL, 0, NULL, NULL,
647 		       CTLFLAG_PERMANENT,
648 		       CTLTYPE_NODE, "machdep", NULL,
649 		       NULL, 0, NULL, 0,
650 		       CTL_MACHDEP, CTL_EOL);
651 }
652 
653 
654