1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Windfarm PowerMac thermal control. SMU based 1 CPU desktop control loops
4  *
5  * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
6  *                    <benh@kernel.crashing.org>
7  *
8  * The algorithm used is the PID control algorithm, used the same
9  * way the published Darwin code does, using the same values that
10  * are present in the Darwin 8.2 snapshot property lists (note however
11  * that none of the code has been re-used, it's a complete re-implementation
12  *
13  * The various control loops found in Darwin config file are:
14  *
15  * PowerMac9,1
16  * ===========
17  *
18  * Has 3 control loops: CPU fans is similar to PowerMac8,1 (though it doesn't
19  * try to play with other control loops fans). Drive bay is rather basic PID
20  * with one sensor and one fan. Slots area is a bit different as the Darwin
21  * driver is supposed to be capable of working in a special "AGP" mode which
22  * involves the presence of an AGP sensor and an AGP fan (possibly on the
23  * AGP card itself). I can't deal with that special mode as I don't have
24  * access to those additional sensor/fans for now (though ultimately, it would
25  * be possible to add sensor objects for them) so I'm only implementing the
26  * basic PCI slot control loop
27  */
28 
29 #include <linux/types.h>
30 #include <linux/errno.h>
31 #include <linux/kernel.h>
32 #include <linux/delay.h>
33 #include <linux/slab.h>
34 #include <linux/init.h>
35 #include <linux/spinlock.h>
36 #include <linux/wait.h>
37 #include <linux/kmod.h>
38 #include <linux/device.h>
39 #include <linux/platform_device.h>
40 #include <asm/prom.h>
41 #include <asm/machdep.h>
42 #include <asm/io.h>
43 #include <asm/sections.h>
44 #include <asm/smu.h>
45 
46 #include "windfarm.h"
47 #include "windfarm_pid.h"
48 
49 #define VERSION "0.4"
50 
51 #undef DEBUG
52 
53 #ifdef DEBUG
54 #define DBG(args...)	printk(args)
55 #else
56 #define DBG(args...)	do { } while(0)
57 #endif
58 
59 /* define this to force CPU overtemp to 74 degree, useful for testing
60  * the overtemp code
61  */
62 #undef HACKED_OVERTEMP
63 
64 /* Controls & sensors */
65 static struct wf_sensor	*sensor_cpu_power;
66 static struct wf_sensor	*sensor_cpu_temp;
67 static struct wf_sensor	*sensor_hd_temp;
68 static struct wf_sensor	*sensor_slots_power;
69 static struct wf_control *fan_cpu_main;
70 static struct wf_control *fan_cpu_second;
71 static struct wf_control *fan_cpu_third;
72 static struct wf_control *fan_hd;
73 static struct wf_control *fan_slots;
74 static struct wf_control *cpufreq_clamp;
75 
76 /* Set to kick the control loop into life */
77 static int wf_smu_all_controls_ok, wf_smu_all_sensors_ok;
78 static bool wf_smu_started;
79 static bool wf_smu_overtemp;
80 
81 /* Failure handling.. could be nicer */
82 #define FAILURE_FAN		0x01
83 #define FAILURE_SENSOR		0x02
84 #define FAILURE_OVERTEMP	0x04
85 
86 static unsigned int wf_smu_failure_state;
87 static int wf_smu_readjust, wf_smu_skipping;
88 
89 /*
90  * ****** CPU Fans Control Loop ******
91  *
92  */
93 
94 
95 #define WF_SMU_CPU_FANS_INTERVAL	1
96 #define WF_SMU_CPU_FANS_MAX_HISTORY	16
97 
98 /* State data used by the cpu fans control loop
99  */
100 struct wf_smu_cpu_fans_state {
101 	int			ticks;
102 	s32			cpu_setpoint;
103 	struct wf_cpu_pid_state	pid;
104 };
105 
106 static struct wf_smu_cpu_fans_state *wf_smu_cpu_fans;
107 
108 
109 
110 /*
111  * ****** Drive Fan Control Loop ******
112  *
113  */
114 
115 struct wf_smu_drive_fans_state {
116 	int			ticks;
117 	s32			setpoint;
118 	struct wf_pid_state	pid;
119 };
120 
121 static struct wf_smu_drive_fans_state *wf_smu_drive_fans;
122 
123 /*
124  * ****** Slots Fan Control Loop ******
125  *
126  */
127 
128 struct wf_smu_slots_fans_state {
129 	int			ticks;
130 	s32			setpoint;
131 	struct wf_pid_state	pid;
132 };
133 
134 static struct wf_smu_slots_fans_state *wf_smu_slots_fans;
135 
136 /*
137  * ***** Implementation *****
138  *
139  */
140 
141 
142 static void wf_smu_create_cpu_fans(void)
143 {
144 	struct wf_cpu_pid_param pid_param;
145 	const struct smu_sdbp_header *hdr;
146 	struct smu_sdbp_cpupiddata *piddata;
147 	struct smu_sdbp_fvt *fvt;
148 	s32 tmax, tdelta, maxpow, powadj;
149 
150 	/* First, locate the PID params in SMU SBD */
151 	hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);
152 	if (hdr == 0) {
153 		printk(KERN_WARNING "windfarm: CPU PID fan config not found "
154 		       "max fan speed\n");
155 		goto fail;
156 	}
157 	piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
158 
159 	/* Get the FVT params for operating point 0 (the only supported one
160 	 * for now) in order to get tmax
161 	 */
162 	hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
163 	if (hdr) {
164 		fvt = (struct smu_sdbp_fvt *)&hdr[1];
165 		tmax = ((s32)fvt->maxtemp) << 16;
166 	} else
167 		tmax = 0x5e0000; /* 94 degree default */
168 
169 	/* Alloc & initialize state */
170 	wf_smu_cpu_fans = kmalloc(sizeof(struct wf_smu_cpu_fans_state),
171 				  GFP_KERNEL);
172 	if (wf_smu_cpu_fans == NULL)
173 		goto fail;
174        	wf_smu_cpu_fans->ticks = 1;
175 
176 	/* Fill PID params */
177 	pid_param.interval = WF_SMU_CPU_FANS_INTERVAL;
178 	pid_param.history_len = piddata->history_len;
179 	if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {
180 		printk(KERN_WARNING "windfarm: History size overflow on "
181 		       "CPU control loop (%d)\n", piddata->history_len);
182 		pid_param.history_len = WF_CPU_PID_MAX_HISTORY;
183 	}
184 	pid_param.gd = piddata->gd;
185 	pid_param.gp = piddata->gp;
186 	pid_param.gr = piddata->gr / pid_param.history_len;
187 
188 	tdelta = ((s32)piddata->target_temp_delta) << 16;
189 	maxpow = ((s32)piddata->max_power) << 16;
190 	powadj = ((s32)piddata->power_adj) << 16;
191 
192 	pid_param.tmax = tmax;
193 	pid_param.ttarget = tmax - tdelta;
194 	pid_param.pmaxadj = maxpow - powadj;
195 
196 	pid_param.min = wf_control_get_min(fan_cpu_main);
197 	pid_param.max = wf_control_get_max(fan_cpu_main);
198 
199 	wf_cpu_pid_init(&wf_smu_cpu_fans->pid, &pid_param);
200 
201 	DBG("wf: CPU Fan control initialized.\n");
202 	DBG("    ttarget=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM\n",
203 	    FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),
204 	    pid_param.min, pid_param.max);
205 
206 	return;
207 
208  fail:
209 	printk(KERN_WARNING "windfarm: CPU fan config not found\n"
210 	       "for this machine model, max fan speed\n");
211 
212 	if (cpufreq_clamp)
213 		wf_control_set_max(cpufreq_clamp);
214 	if (fan_cpu_main)
215 		wf_control_set_max(fan_cpu_main);
216 }
217 
218 static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state *st)
219 {
220 	s32 new_setpoint, temp, power;
221 	int rc;
222 
223 	if (--st->ticks != 0) {
224 		if (wf_smu_readjust)
225 			goto readjust;
226 		return;
227 	}
228 	st->ticks = WF_SMU_CPU_FANS_INTERVAL;
229 
230 	rc = wf_sensor_get(sensor_cpu_temp, &temp);
231 	if (rc) {
232 		printk(KERN_WARNING "windfarm: CPU temp sensor error %d\n",
233 		       rc);
234 		wf_smu_failure_state |= FAILURE_SENSOR;
235 		return;
236 	}
237 
238 	rc = wf_sensor_get(sensor_cpu_power, &power);
239 	if (rc) {
240 		printk(KERN_WARNING "windfarm: CPU power sensor error %d\n",
241 		       rc);
242 		wf_smu_failure_state |= FAILURE_SENSOR;
243 		return;
244 	}
245 
246 	DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",
247 	    FIX32TOPRINT(temp), FIX32TOPRINT(power));
248 
249 #ifdef HACKED_OVERTEMP
250 	if (temp > 0x4a0000)
251 		wf_smu_failure_state |= FAILURE_OVERTEMP;
252 #else
253 	if (temp > st->pid.param.tmax)
254 		wf_smu_failure_state |= FAILURE_OVERTEMP;
255 #endif
256 	new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);
257 
258 	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
259 
260 	if (st->cpu_setpoint == new_setpoint)
261 		return;
262 	st->cpu_setpoint = new_setpoint;
263  readjust:
264 	if (fan_cpu_main && wf_smu_failure_state == 0) {
265 		rc = wf_control_set(fan_cpu_main, st->cpu_setpoint);
266 		if (rc) {
267 			printk(KERN_WARNING "windfarm: CPU main fan"
268 			       " error %d\n", rc);
269 			wf_smu_failure_state |= FAILURE_FAN;
270 		}
271 	}
272 	if (fan_cpu_second && wf_smu_failure_state == 0) {
273 		rc = wf_control_set(fan_cpu_second, st->cpu_setpoint);
274 		if (rc) {
275 			printk(KERN_WARNING "windfarm: CPU second fan"
276 			       " error %d\n", rc);
277 			wf_smu_failure_state |= FAILURE_FAN;
278 		}
279 	}
280 	if (fan_cpu_third && wf_smu_failure_state == 0) {
281 		rc = wf_control_set(fan_cpu_third, st->cpu_setpoint);
282 		if (rc) {
283 			printk(KERN_WARNING "windfarm: CPU third fan"
284 			       " error %d\n", rc);
285 			wf_smu_failure_state |= FAILURE_FAN;
286 		}
287 	}
288 }
289 
290 static void wf_smu_create_drive_fans(void)
291 {
292 	struct wf_pid_param param = {
293 		.interval	= 5,
294 		.history_len	= 2,
295 		.gd		= 0x01e00000,
296 		.gp		= 0x00500000,
297 		.gr		= 0x00000000,
298 		.itarget	= 0x00200000,
299 	};
300 
301 	/* Alloc & initialize state */
302 	wf_smu_drive_fans = kmalloc(sizeof(struct wf_smu_drive_fans_state),
303 					GFP_KERNEL);
304 	if (wf_smu_drive_fans == NULL) {
305 		printk(KERN_WARNING "windfarm: Memory allocation error"
306 		       " max fan speed\n");
307 		goto fail;
308 	}
309        	wf_smu_drive_fans->ticks = 1;
310 
311 	/* Fill PID params */
312 	param.additive = (fan_hd->type == WF_CONTROL_RPM_FAN);
313 	param.min = wf_control_get_min(fan_hd);
314 	param.max = wf_control_get_max(fan_hd);
315 	wf_pid_init(&wf_smu_drive_fans->pid, &param);
316 
317 	DBG("wf: Drive Fan control initialized.\n");
318 	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
319 	    FIX32TOPRINT(param.itarget), param.min, param.max);
320 	return;
321 
322  fail:
323 	if (fan_hd)
324 		wf_control_set_max(fan_hd);
325 }
326 
327 static void wf_smu_drive_fans_tick(struct wf_smu_drive_fans_state *st)
328 {
329 	s32 new_setpoint, temp;
330 	int rc;
331 
332 	if (--st->ticks != 0) {
333 		if (wf_smu_readjust)
334 			goto readjust;
335 		return;
336 	}
337 	st->ticks = st->pid.param.interval;
338 
339 	rc = wf_sensor_get(sensor_hd_temp, &temp);
340 	if (rc) {
341 		printk(KERN_WARNING "windfarm: HD temp sensor error %d\n",
342 		       rc);
343 		wf_smu_failure_state |= FAILURE_SENSOR;
344 		return;
345 	}
346 
347 	DBG("wf_smu: Drive Fans tick ! HD temp: %d.%03d\n",
348 	    FIX32TOPRINT(temp));
349 
350 	if (temp > (st->pid.param.itarget + 0x50000))
351 		wf_smu_failure_state |= FAILURE_OVERTEMP;
352 
353 	new_setpoint = wf_pid_run(&st->pid, temp);
354 
355 	DBG("wf_smu: new_setpoint: %d\n", (int)new_setpoint);
356 
357 	if (st->setpoint == new_setpoint)
358 		return;
359 	st->setpoint = new_setpoint;
360  readjust:
361 	if (fan_hd && wf_smu_failure_state == 0) {
362 		rc = wf_control_set(fan_hd, st->setpoint);
363 		if (rc) {
364 			printk(KERN_WARNING "windfarm: HD fan error %d\n",
365 			       rc);
366 			wf_smu_failure_state |= FAILURE_FAN;
367 		}
368 	}
369 }
370 
371 static void wf_smu_create_slots_fans(void)
372 {
373 	struct wf_pid_param param = {
374 		.interval	= 1,
375 		.history_len	= 8,
376 		.gd		= 0x00000000,
377 		.gp		= 0x00000000,
378 		.gr		= 0x00020000,
379 		.itarget	= 0x00000000
380 	};
381 
382 	/* Alloc & initialize state */
383 	wf_smu_slots_fans = kmalloc(sizeof(struct wf_smu_slots_fans_state),
384 					GFP_KERNEL);
385 	if (wf_smu_slots_fans == NULL) {
386 		printk(KERN_WARNING "windfarm: Memory allocation error"
387 		       " max fan speed\n");
388 		goto fail;
389 	}
390        	wf_smu_slots_fans->ticks = 1;
391 
392 	/* Fill PID params */
393 	param.additive = (fan_slots->type == WF_CONTROL_RPM_FAN);
394 	param.min = wf_control_get_min(fan_slots);
395 	param.max = wf_control_get_max(fan_slots);
396 	wf_pid_init(&wf_smu_slots_fans->pid, &param);
397 
398 	DBG("wf: Slots Fan control initialized.\n");
399 	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
400 	    FIX32TOPRINT(param.itarget), param.min, param.max);
401 	return;
402 
403  fail:
404 	if (fan_slots)
405 		wf_control_set_max(fan_slots);
406 }
407 
408 static void wf_smu_slots_fans_tick(struct wf_smu_slots_fans_state *st)
409 {
410 	s32 new_setpoint, power;
411 	int rc;
412 
413 	if (--st->ticks != 0) {
414 		if (wf_smu_readjust)
415 			goto readjust;
416 		return;
417 	}
418 	st->ticks = st->pid.param.interval;
419 
420 	rc = wf_sensor_get(sensor_slots_power, &power);
421 	if (rc) {
422 		printk(KERN_WARNING "windfarm: Slots power sensor error %d\n",
423 		       rc);
424 		wf_smu_failure_state |= FAILURE_SENSOR;
425 		return;
426 	}
427 
428 	DBG("wf_smu: Slots Fans tick ! Slots power: %d.%03d\n",
429 	    FIX32TOPRINT(power));
430 
431 #if 0 /* Check what makes a good overtemp condition */
432 	if (power > (st->pid.param.itarget + 0x50000))
433 		wf_smu_failure_state |= FAILURE_OVERTEMP;
434 #endif
435 
436 	new_setpoint = wf_pid_run(&st->pid, power);
437 
438 	DBG("wf_smu: new_setpoint: %d\n", (int)new_setpoint);
439 
440 	if (st->setpoint == new_setpoint)
441 		return;
442 	st->setpoint = new_setpoint;
443  readjust:
444 	if (fan_slots && wf_smu_failure_state == 0) {
445 		rc = wf_control_set(fan_slots, st->setpoint);
446 		if (rc) {
447 			printk(KERN_WARNING "windfarm: Slots fan error %d\n",
448 			       rc);
449 			wf_smu_failure_state |= FAILURE_FAN;
450 		}
451 	}
452 }
453 
454 
455 /*
456  * ****** Setup / Init / Misc ... ******
457  *
458  */
459 
460 static void wf_smu_tick(void)
461 {
462 	unsigned int last_failure = wf_smu_failure_state;
463 	unsigned int new_failure;
464 
465 	if (!wf_smu_started) {
466 		DBG("wf: creating control loops !\n");
467 		wf_smu_create_drive_fans();
468 		wf_smu_create_slots_fans();
469 		wf_smu_create_cpu_fans();
470 		wf_smu_started = true;
471 	}
472 
473 	/* Skipping ticks */
474 	if (wf_smu_skipping && --wf_smu_skipping)
475 		return;
476 
477 	wf_smu_failure_state = 0;
478 	if (wf_smu_drive_fans)
479 		wf_smu_drive_fans_tick(wf_smu_drive_fans);
480 	if (wf_smu_slots_fans)
481 		wf_smu_slots_fans_tick(wf_smu_slots_fans);
482 	if (wf_smu_cpu_fans)
483 		wf_smu_cpu_fans_tick(wf_smu_cpu_fans);
484 
485 	wf_smu_readjust = 0;
486 	new_failure = wf_smu_failure_state & ~last_failure;
487 
488 	/* If entering failure mode, clamp cpufreq and ramp all
489 	 * fans to full speed.
490 	 */
491 	if (wf_smu_failure_state && !last_failure) {
492 		if (cpufreq_clamp)
493 			wf_control_set_max(cpufreq_clamp);
494 		if (fan_cpu_main)
495 			wf_control_set_max(fan_cpu_main);
496 		if (fan_cpu_second)
497 			wf_control_set_max(fan_cpu_second);
498 		if (fan_cpu_third)
499 			wf_control_set_max(fan_cpu_third);
500 		if (fan_hd)
501 			wf_control_set_max(fan_hd);
502 		if (fan_slots)
503 			wf_control_set_max(fan_slots);
504 	}
505 
506 	/* If leaving failure mode, unclamp cpufreq and readjust
507 	 * all fans on next iteration
508 	 */
509 	if (!wf_smu_failure_state && last_failure) {
510 		if (cpufreq_clamp)
511 			wf_control_set_min(cpufreq_clamp);
512 		wf_smu_readjust = 1;
513 	}
514 
515 	/* Overtemp condition detected, notify and start skipping a couple
516 	 * ticks to let the temperature go down
517 	 */
518 	if (new_failure & FAILURE_OVERTEMP) {
519 		wf_set_overtemp();
520 		wf_smu_skipping = 2;
521 		wf_smu_overtemp = true;
522 	}
523 
524 	/* We only clear the overtemp condition if overtemp is cleared
525 	 * _and_ no other failure is present. Since a sensor error will
526 	 * clear the overtemp condition (can't measure temperature) at
527 	 * the control loop levels, but we don't want to keep it clear
528 	 * here in this case
529 	 */
530 	if (!wf_smu_failure_state && wf_smu_overtemp) {
531 		wf_clear_overtemp();
532 		wf_smu_overtemp = false;
533 	}
534 }
535 
536 
537 static void wf_smu_new_control(struct wf_control *ct)
538 {
539 	if (wf_smu_all_controls_ok)
540 		return;
541 
542 	if (fan_cpu_main == NULL && !strcmp(ct->name, "cpu-rear-fan-0")) {
543 		if (wf_get_control(ct) == 0)
544 			fan_cpu_main = ct;
545 	}
546 
547 	if (fan_cpu_second == NULL && !strcmp(ct->name, "cpu-rear-fan-1")) {
548 		if (wf_get_control(ct) == 0)
549 			fan_cpu_second = ct;
550 	}
551 
552 	if (fan_cpu_third == NULL && !strcmp(ct->name, "cpu-front-fan-0")) {
553 		if (wf_get_control(ct) == 0)
554 			fan_cpu_third = ct;
555 	}
556 
557 	if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
558 		if (wf_get_control(ct) == 0)
559 			cpufreq_clamp = ct;
560 	}
561 
562 	if (fan_hd == NULL && !strcmp(ct->name, "drive-bay-fan")) {
563 		if (wf_get_control(ct) == 0)
564 			fan_hd = ct;
565 	}
566 
567 	if (fan_slots == NULL && !strcmp(ct->name, "slots-fan")) {
568 		if (wf_get_control(ct) == 0)
569 			fan_slots = ct;
570 	}
571 
572 	if (fan_cpu_main && (fan_cpu_second || fan_cpu_third) && fan_hd &&
573 	    fan_slots && cpufreq_clamp)
574 		wf_smu_all_controls_ok = 1;
575 }
576 
577 static void wf_smu_new_sensor(struct wf_sensor *sr)
578 {
579 	if (wf_smu_all_sensors_ok)
580 		return;
581 
582 	if (sensor_cpu_power == NULL && !strcmp(sr->name, "cpu-power")) {
583 		if (wf_get_sensor(sr) == 0)
584 			sensor_cpu_power = sr;
585 	}
586 
587 	if (sensor_cpu_temp == NULL && !strcmp(sr->name, "cpu-temp")) {
588 		if (wf_get_sensor(sr) == 0)
589 			sensor_cpu_temp = sr;
590 	}
591 
592 	if (sensor_hd_temp == NULL && !strcmp(sr->name, "hd-temp")) {
593 		if (wf_get_sensor(sr) == 0)
594 			sensor_hd_temp = sr;
595 	}
596 
597 	if (sensor_slots_power == NULL && !strcmp(sr->name, "slots-power")) {
598 		if (wf_get_sensor(sr) == 0)
599 			sensor_slots_power = sr;
600 	}
601 
602 	if (sensor_cpu_power && sensor_cpu_temp &&
603 	    sensor_hd_temp && sensor_slots_power)
604 		wf_smu_all_sensors_ok = 1;
605 }
606 
607 
608 static int wf_smu_notify(struct notifier_block *self,
609 			       unsigned long event, void *data)
610 {
611 	switch(event) {
612 	case WF_EVENT_NEW_CONTROL:
613 		DBG("wf: new control %s detected\n",
614 		    ((struct wf_control *)data)->name);
615 		wf_smu_new_control(data);
616 		wf_smu_readjust = 1;
617 		break;
618 	case WF_EVENT_NEW_SENSOR:
619 		DBG("wf: new sensor %s detected\n",
620 		    ((struct wf_sensor *)data)->name);
621 		wf_smu_new_sensor(data);
622 		break;
623 	case WF_EVENT_TICK:
624 		if (wf_smu_all_controls_ok && wf_smu_all_sensors_ok)
625 			wf_smu_tick();
626 	}
627 
628 	return 0;
629 }
630 
631 static struct notifier_block wf_smu_events = {
632 	.notifier_call	= wf_smu_notify,
633 };
634 
635 static int wf_init_pm(void)
636 {
637 	printk(KERN_INFO "windfarm: Initializing for Desktop G5 model\n");
638 
639 	return 0;
640 }
641 
642 static int wf_smu_probe(struct platform_device *ddev)
643 {
644 	wf_register_client(&wf_smu_events);
645 
646 	return 0;
647 }
648 
649 static int wf_smu_remove(struct platform_device *ddev)
650 {
651 	wf_unregister_client(&wf_smu_events);
652 
653 	/* XXX We don't have yet a guarantee that our callback isn't
654 	 * in progress when returning from wf_unregister_client, so
655 	 * we add an arbitrary delay. I'll have to fix that in the core
656 	 */
657 	msleep(1000);
658 
659 	/* Release all sensors */
660 	/* One more crappy race: I don't think we have any guarantee here
661 	 * that the attribute callback won't race with the sensor beeing
662 	 * disposed of, and I'm not 100% certain what best way to deal
663 	 * with that except by adding locks all over... I'll do that
664 	 * eventually but heh, who ever rmmod this module anyway ?
665 	 */
666 	if (sensor_cpu_power)
667 		wf_put_sensor(sensor_cpu_power);
668 	if (sensor_cpu_temp)
669 		wf_put_sensor(sensor_cpu_temp);
670 	if (sensor_hd_temp)
671 		wf_put_sensor(sensor_hd_temp);
672 	if (sensor_slots_power)
673 		wf_put_sensor(sensor_slots_power);
674 
675 	/* Release all controls */
676 	if (fan_cpu_main)
677 		wf_put_control(fan_cpu_main);
678 	if (fan_cpu_second)
679 		wf_put_control(fan_cpu_second);
680 	if (fan_cpu_third)
681 		wf_put_control(fan_cpu_third);
682 	if (fan_hd)
683 		wf_put_control(fan_hd);
684 	if (fan_slots)
685 		wf_put_control(fan_slots);
686 	if (cpufreq_clamp)
687 		wf_put_control(cpufreq_clamp);
688 
689 	/* Destroy control loops state structures */
690 	kfree(wf_smu_slots_fans);
691 	kfree(wf_smu_drive_fans);
692 	kfree(wf_smu_cpu_fans);
693 
694 	return 0;
695 }
696 
697 static struct platform_driver wf_smu_driver = {
698         .probe = wf_smu_probe,
699         .remove = wf_smu_remove,
700 	.driver = {
701 		.name = "windfarm",
702 	},
703 };
704 
705 
706 static int __init wf_smu_init(void)
707 {
708 	int rc = -ENODEV;
709 
710 	if (of_machine_is_compatible("PowerMac9,1"))
711 		rc = wf_init_pm();
712 
713 	if (rc == 0) {
714 #ifdef MODULE
715 		request_module("windfarm_smu_controls");
716 		request_module("windfarm_smu_sensors");
717 		request_module("windfarm_lm75_sensor");
718 		request_module("windfarm_cpufreq_clamp");
719 
720 #endif /* MODULE */
721 		platform_driver_register(&wf_smu_driver);
722 	}
723 
724 	return rc;
725 }
726 
727 static void __exit wf_smu_exit(void)
728 {
729 
730 	platform_driver_unregister(&wf_smu_driver);
731 }
732 
733 
734 module_init(wf_smu_init);
735 module_exit(wf_smu_exit);
736 
737 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
738 MODULE_DESCRIPTION("Thermal control logic for PowerMac9,1");
739 MODULE_LICENSE("GPL");
740 
741 MODULE_ALIAS("platform:windfarm");
742