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 <linux/of.h>
41 
42 #include <asm/machdep.h>
43 #include <asm/io.h>
44 #include <asm/sections.h>
45 #include <asm/smu.h>
46 
47 #include "windfarm.h"
48 #include "windfarm_pid.h"
49 
50 #define VERSION "0.4"
51 
52 #undef DEBUG
53 
54 #ifdef DEBUG
55 #define DBG(args...)	printk(args)
56 #else
57 #define DBG(args...)	do { } while(0)
58 #endif
59 
60 /* define this to force CPU overtemp to 74 degree, useful for testing
61  * the overtemp code
62  */
63 #undef HACKED_OVERTEMP
64 
65 /* Controls & sensors */
66 static struct wf_sensor	*sensor_cpu_power;
67 static struct wf_sensor	*sensor_cpu_temp;
68 static struct wf_sensor	*sensor_hd_temp;
69 static struct wf_sensor	*sensor_slots_power;
70 static struct wf_control *fan_cpu_main;
71 static struct wf_control *fan_cpu_second;
72 static struct wf_control *fan_cpu_third;
73 static struct wf_control *fan_hd;
74 static struct wf_control *fan_slots;
75 static struct wf_control *cpufreq_clamp;
76 
77 /* Set to kick the control loop into life */
78 static int wf_smu_all_controls_ok, wf_smu_all_sensors_ok;
79 static bool wf_smu_started;
80 static bool wf_smu_overtemp;
81 
82 /* Failure handling.. could be nicer */
83 #define FAILURE_FAN		0x01
84 #define FAILURE_SENSOR		0x02
85 #define FAILURE_OVERTEMP	0x04
86 
87 static unsigned int wf_smu_failure_state;
88 static int wf_smu_readjust, wf_smu_skipping;
89 
90 /*
91  * ****** CPU Fans Control Loop ******
92  *
93  */
94 
95 
96 #define WF_SMU_CPU_FANS_INTERVAL	1
97 #define WF_SMU_CPU_FANS_MAX_HISTORY	16
98 
99 /* State data used by the cpu fans control loop
100  */
101 struct wf_smu_cpu_fans_state {
102 	int			ticks;
103 	s32			cpu_setpoint;
104 	struct wf_cpu_pid_state	pid;
105 };
106 
107 static struct wf_smu_cpu_fans_state *wf_smu_cpu_fans;
108 
109 
110 
111 /*
112  * ****** Drive Fan Control Loop ******
113  *
114  */
115 
116 struct wf_smu_drive_fans_state {
117 	int			ticks;
118 	s32			setpoint;
119 	struct wf_pid_state	pid;
120 };
121 
122 static struct wf_smu_drive_fans_state *wf_smu_drive_fans;
123 
124 /*
125  * ****** Slots Fan Control Loop ******
126  *
127  */
128 
129 struct wf_smu_slots_fans_state {
130 	int			ticks;
131 	s32			setpoint;
132 	struct wf_pid_state	pid;
133 };
134 
135 static struct wf_smu_slots_fans_state *wf_smu_slots_fans;
136 
137 /*
138  * ***** Implementation *****
139  *
140  */
141 
142 
143 static void wf_smu_create_cpu_fans(void)
144 {
145 	struct wf_cpu_pid_param pid_param;
146 	const struct smu_sdbp_header *hdr;
147 	struct smu_sdbp_cpupiddata *piddata;
148 	struct smu_sdbp_fvt *fvt;
149 	s32 tmax, tdelta, maxpow, powadj;
150 
151 	/* First, locate the PID params in SMU SBD */
152 	hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);
153 	if (!hdr) {
154 		printk(KERN_WARNING "windfarm: CPU PID fan config not found "
155 		       "max fan speed\n");
156 		goto fail;
157 	}
158 	piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
159 
160 	/* Get the FVT params for operating point 0 (the only supported one
161 	 * for now) in order to get tmax
162 	 */
163 	hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
164 	if (hdr) {
165 		fvt = (struct smu_sdbp_fvt *)&hdr[1];
166 		tmax = ((s32)fvt->maxtemp) << 16;
167 	} else
168 		tmax = 0x5e0000; /* 94 degree default */
169 
170 	/* Alloc & initialize state */
171 	wf_smu_cpu_fans = kmalloc(sizeof(struct wf_smu_cpu_fans_state),
172 				  GFP_KERNEL);
173 	if (wf_smu_cpu_fans == NULL)
174 		goto fail;
175        	wf_smu_cpu_fans->ticks = 1;
176 
177 	/* Fill PID params */
178 	pid_param.interval = WF_SMU_CPU_FANS_INTERVAL;
179 	pid_param.history_len = piddata->history_len;
180 	if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {
181 		printk(KERN_WARNING "windfarm: History size overflow on "
182 		       "CPU control loop (%d)\n", piddata->history_len);
183 		pid_param.history_len = WF_CPU_PID_MAX_HISTORY;
184 	}
185 	pid_param.gd = piddata->gd;
186 	pid_param.gp = piddata->gp;
187 	pid_param.gr = piddata->gr / pid_param.history_len;
188 
189 	tdelta = ((s32)piddata->target_temp_delta) << 16;
190 	maxpow = ((s32)piddata->max_power) << 16;
191 	powadj = ((s32)piddata->power_adj) << 16;
192 
193 	pid_param.tmax = tmax;
194 	pid_param.ttarget = tmax - tdelta;
195 	pid_param.pmaxadj = maxpow - powadj;
196 
197 	pid_param.min = wf_control_get_min(fan_cpu_main);
198 	pid_param.max = wf_control_get_max(fan_cpu_main);
199 
200 	wf_cpu_pid_init(&wf_smu_cpu_fans->pid, &pid_param);
201 
202 	DBG("wf: CPU Fan control initialized.\n");
203 	DBG("    ttarget=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM\n",
204 	    FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),
205 	    pid_param.min, pid_param.max);
206 
207 	return;
208 
209  fail:
210 	printk(KERN_WARNING "windfarm: CPU fan config not found\n"
211 	       "for this machine model, max fan speed\n");
212 
213 	if (cpufreq_clamp)
214 		wf_control_set_max(cpufreq_clamp);
215 	if (fan_cpu_main)
216 		wf_control_set_max(fan_cpu_main);
217 }
218 
219 static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state *st)
220 {
221 	s32 new_setpoint, temp, power;
222 	int rc;
223 
224 	if (--st->ticks != 0) {
225 		if (wf_smu_readjust)
226 			goto readjust;
227 		return;
228 	}
229 	st->ticks = WF_SMU_CPU_FANS_INTERVAL;
230 
231 	rc = wf_sensor_get(sensor_cpu_temp, &temp);
232 	if (rc) {
233 		printk(KERN_WARNING "windfarm: CPU temp sensor error %d\n",
234 		       rc);
235 		wf_smu_failure_state |= FAILURE_SENSOR;
236 		return;
237 	}
238 
239 	rc = wf_sensor_get(sensor_cpu_power, &power);
240 	if (rc) {
241 		printk(KERN_WARNING "windfarm: CPU power sensor error %d\n",
242 		       rc);
243 		wf_smu_failure_state |= FAILURE_SENSOR;
244 		return;
245 	}
246 
247 	DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",
248 	    FIX32TOPRINT(temp), FIX32TOPRINT(power));
249 
250 #ifdef HACKED_OVERTEMP
251 	if (temp > 0x4a0000)
252 		wf_smu_failure_state |= FAILURE_OVERTEMP;
253 #else
254 	if (temp > st->pid.param.tmax)
255 		wf_smu_failure_state |= FAILURE_OVERTEMP;
256 #endif
257 	new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);
258 
259 	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
260 
261 	if (st->cpu_setpoint == new_setpoint)
262 		return;
263 	st->cpu_setpoint = new_setpoint;
264  readjust:
265 	if (fan_cpu_main && wf_smu_failure_state == 0) {
266 		rc = wf_control_set(fan_cpu_main, st->cpu_setpoint);
267 		if (rc) {
268 			printk(KERN_WARNING "windfarm: CPU main fan"
269 			       " error %d\n", rc);
270 			wf_smu_failure_state |= FAILURE_FAN;
271 		}
272 	}
273 	if (fan_cpu_second && wf_smu_failure_state == 0) {
274 		rc = wf_control_set(fan_cpu_second, st->cpu_setpoint);
275 		if (rc) {
276 			printk(KERN_WARNING "windfarm: CPU second fan"
277 			       " error %d\n", rc);
278 			wf_smu_failure_state |= FAILURE_FAN;
279 		}
280 	}
281 	if (fan_cpu_third && wf_smu_failure_state == 0) {
282 		rc = wf_control_set(fan_cpu_third, st->cpu_setpoint);
283 		if (rc) {
284 			printk(KERN_WARNING "windfarm: CPU third fan"
285 			       " error %d\n", rc);
286 			wf_smu_failure_state |= FAILURE_FAN;
287 		}
288 	}
289 }
290 
291 static void wf_smu_create_drive_fans(void)
292 {
293 	struct wf_pid_param param = {
294 		.interval	= 5,
295 		.history_len	= 2,
296 		.gd		= 0x01e00000,
297 		.gp		= 0x00500000,
298 		.gr		= 0x00000000,
299 		.itarget	= 0x00200000,
300 	};
301 
302 	/* Alloc & initialize state */
303 	wf_smu_drive_fans = kmalloc(sizeof(struct wf_smu_drive_fans_state),
304 					GFP_KERNEL);
305 	if (wf_smu_drive_fans == NULL) {
306 		printk(KERN_WARNING "windfarm: Memory allocation error"
307 		       " max fan speed\n");
308 		goto fail;
309 	}
310        	wf_smu_drive_fans->ticks = 1;
311 
312 	/* Fill PID params */
313 	param.additive = (fan_hd->type == WF_CONTROL_RPM_FAN);
314 	param.min = wf_control_get_min(fan_hd);
315 	param.max = wf_control_get_max(fan_hd);
316 	wf_pid_init(&wf_smu_drive_fans->pid, &param);
317 
318 	DBG("wf: Drive Fan control initialized.\n");
319 	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
320 	    FIX32TOPRINT(param.itarget), param.min, param.max);
321 	return;
322 
323  fail:
324 	if (fan_hd)
325 		wf_control_set_max(fan_hd);
326 }
327 
328 static void wf_smu_drive_fans_tick(struct wf_smu_drive_fans_state *st)
329 {
330 	s32 new_setpoint, temp;
331 	int rc;
332 
333 	if (--st->ticks != 0) {
334 		if (wf_smu_readjust)
335 			goto readjust;
336 		return;
337 	}
338 	st->ticks = st->pid.param.interval;
339 
340 	rc = wf_sensor_get(sensor_hd_temp, &temp);
341 	if (rc) {
342 		printk(KERN_WARNING "windfarm: HD temp sensor error %d\n",
343 		       rc);
344 		wf_smu_failure_state |= FAILURE_SENSOR;
345 		return;
346 	}
347 
348 	DBG("wf_smu: Drive Fans tick ! HD temp: %d.%03d\n",
349 	    FIX32TOPRINT(temp));
350 
351 	if (temp > (st->pid.param.itarget + 0x50000))
352 		wf_smu_failure_state |= FAILURE_OVERTEMP;
353 
354 	new_setpoint = wf_pid_run(&st->pid, temp);
355 
356 	DBG("wf_smu: new_setpoint: %d\n", (int)new_setpoint);
357 
358 	if (st->setpoint == new_setpoint)
359 		return;
360 	st->setpoint = new_setpoint;
361  readjust:
362 	if (fan_hd && wf_smu_failure_state == 0) {
363 		rc = wf_control_set(fan_hd, st->setpoint);
364 		if (rc) {
365 			printk(KERN_WARNING "windfarm: HD fan error %d\n",
366 			       rc);
367 			wf_smu_failure_state |= FAILURE_FAN;
368 		}
369 	}
370 }
371 
372 static void wf_smu_create_slots_fans(void)
373 {
374 	struct wf_pid_param param = {
375 		.interval	= 1,
376 		.history_len	= 8,
377 		.gd		= 0x00000000,
378 		.gp		= 0x00000000,
379 		.gr		= 0x00020000,
380 		.itarget	= 0x00000000
381 	};
382 
383 	/* Alloc & initialize state */
384 	wf_smu_slots_fans = kmalloc(sizeof(struct wf_smu_slots_fans_state),
385 					GFP_KERNEL);
386 	if (wf_smu_slots_fans == NULL) {
387 		printk(KERN_WARNING "windfarm: Memory allocation error"
388 		       " max fan speed\n");
389 		goto fail;
390 	}
391        	wf_smu_slots_fans->ticks = 1;
392 
393 	/* Fill PID params */
394 	param.additive = (fan_slots->type == WF_CONTROL_RPM_FAN);
395 	param.min = wf_control_get_min(fan_slots);
396 	param.max = wf_control_get_max(fan_slots);
397 	wf_pid_init(&wf_smu_slots_fans->pid, &param);
398 
399 	DBG("wf: Slots Fan control initialized.\n");
400 	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
401 	    FIX32TOPRINT(param.itarget), param.min, param.max);
402 	return;
403 
404  fail:
405 	if (fan_slots)
406 		wf_control_set_max(fan_slots);
407 }
408 
409 static void wf_smu_slots_fans_tick(struct wf_smu_slots_fans_state *st)
410 {
411 	s32 new_setpoint, power;
412 	int rc;
413 
414 	if (--st->ticks != 0) {
415 		if (wf_smu_readjust)
416 			goto readjust;
417 		return;
418 	}
419 	st->ticks = st->pid.param.interval;
420 
421 	rc = wf_sensor_get(sensor_slots_power, &power);
422 	if (rc) {
423 		printk(KERN_WARNING "windfarm: Slots power sensor error %d\n",
424 		       rc);
425 		wf_smu_failure_state |= FAILURE_SENSOR;
426 		return;
427 	}
428 
429 	DBG("wf_smu: Slots Fans tick ! Slots power: %d.%03d\n",
430 	    FIX32TOPRINT(power));
431 
432 #if 0 /* Check what makes a good overtemp condition */
433 	if (power > (st->pid.param.itarget + 0x50000))
434 		wf_smu_failure_state |= FAILURE_OVERTEMP;
435 #endif
436 
437 	new_setpoint = wf_pid_run(&st->pid, power);
438 
439 	DBG("wf_smu: new_setpoint: %d\n", (int)new_setpoint);
440 
441 	if (st->setpoint == new_setpoint)
442 		return;
443 	st->setpoint = new_setpoint;
444  readjust:
445 	if (fan_slots && wf_smu_failure_state == 0) {
446 		rc = wf_control_set(fan_slots, st->setpoint);
447 		if (rc) {
448 			printk(KERN_WARNING "windfarm: Slots fan error %d\n",
449 			       rc);
450 			wf_smu_failure_state |= FAILURE_FAN;
451 		}
452 	}
453 }
454 
455 
456 /*
457  * ****** Setup / Init / Misc ... ******
458  *
459  */
460 
461 static void wf_smu_tick(void)
462 {
463 	unsigned int last_failure = wf_smu_failure_state;
464 	unsigned int new_failure;
465 
466 	if (!wf_smu_started) {
467 		DBG("wf: creating control loops !\n");
468 		wf_smu_create_drive_fans();
469 		wf_smu_create_slots_fans();
470 		wf_smu_create_cpu_fans();
471 		wf_smu_started = true;
472 	}
473 
474 	/* Skipping ticks */
475 	if (wf_smu_skipping && --wf_smu_skipping)
476 		return;
477 
478 	wf_smu_failure_state = 0;
479 	if (wf_smu_drive_fans)
480 		wf_smu_drive_fans_tick(wf_smu_drive_fans);
481 	if (wf_smu_slots_fans)
482 		wf_smu_slots_fans_tick(wf_smu_slots_fans);
483 	if (wf_smu_cpu_fans)
484 		wf_smu_cpu_fans_tick(wf_smu_cpu_fans);
485 
486 	wf_smu_readjust = 0;
487 	new_failure = wf_smu_failure_state & ~last_failure;
488 
489 	/* If entering failure mode, clamp cpufreq and ramp all
490 	 * fans to full speed.
491 	 */
492 	if (wf_smu_failure_state && !last_failure) {
493 		if (cpufreq_clamp)
494 			wf_control_set_max(cpufreq_clamp);
495 		if (fan_cpu_main)
496 			wf_control_set_max(fan_cpu_main);
497 		if (fan_cpu_second)
498 			wf_control_set_max(fan_cpu_second);
499 		if (fan_cpu_third)
500 			wf_control_set_max(fan_cpu_third);
501 		if (fan_hd)
502 			wf_control_set_max(fan_hd);
503 		if (fan_slots)
504 			wf_control_set_max(fan_slots);
505 	}
506 
507 	/* If leaving failure mode, unclamp cpufreq and readjust
508 	 * all fans on next iteration
509 	 */
510 	if (!wf_smu_failure_state && last_failure) {
511 		if (cpufreq_clamp)
512 			wf_control_set_min(cpufreq_clamp);
513 		wf_smu_readjust = 1;
514 	}
515 
516 	/* Overtemp condition detected, notify and start skipping a couple
517 	 * ticks to let the temperature go down
518 	 */
519 	if (new_failure & FAILURE_OVERTEMP) {
520 		wf_set_overtemp();
521 		wf_smu_skipping = 2;
522 		wf_smu_overtemp = true;
523 	}
524 
525 	/* We only clear the overtemp condition if overtemp is cleared
526 	 * _and_ no other failure is present. Since a sensor error will
527 	 * clear the overtemp condition (can't measure temperature) at
528 	 * the control loop levels, but we don't want to keep it clear
529 	 * here in this case
530 	 */
531 	if (!wf_smu_failure_state && wf_smu_overtemp) {
532 		wf_clear_overtemp();
533 		wf_smu_overtemp = false;
534 	}
535 }
536 
537 
538 static void wf_smu_new_control(struct wf_control *ct)
539 {
540 	if (wf_smu_all_controls_ok)
541 		return;
542 
543 	if (fan_cpu_main == NULL && !strcmp(ct->name, "cpu-rear-fan-0")) {
544 		if (wf_get_control(ct) == 0)
545 			fan_cpu_main = ct;
546 	}
547 
548 	if (fan_cpu_second == NULL && !strcmp(ct->name, "cpu-rear-fan-1")) {
549 		if (wf_get_control(ct) == 0)
550 			fan_cpu_second = ct;
551 	}
552 
553 	if (fan_cpu_third == NULL && !strcmp(ct->name, "cpu-front-fan-0")) {
554 		if (wf_get_control(ct) == 0)
555 			fan_cpu_third = ct;
556 	}
557 
558 	if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
559 		if (wf_get_control(ct) == 0)
560 			cpufreq_clamp = ct;
561 	}
562 
563 	if (fan_hd == NULL && !strcmp(ct->name, "drive-bay-fan")) {
564 		if (wf_get_control(ct) == 0)
565 			fan_hd = ct;
566 	}
567 
568 	if (fan_slots == NULL && !strcmp(ct->name, "slots-fan")) {
569 		if (wf_get_control(ct) == 0)
570 			fan_slots = ct;
571 	}
572 
573 	if (fan_cpu_main && (fan_cpu_second || fan_cpu_third) && fan_hd &&
574 	    fan_slots && cpufreq_clamp)
575 		wf_smu_all_controls_ok = 1;
576 }
577 
578 static void wf_smu_new_sensor(struct wf_sensor *sr)
579 {
580 	if (wf_smu_all_sensors_ok)
581 		return;
582 
583 	if (sensor_cpu_power == NULL && !strcmp(sr->name, "cpu-power")) {
584 		if (wf_get_sensor(sr) == 0)
585 			sensor_cpu_power = sr;
586 	}
587 
588 	if (sensor_cpu_temp == NULL && !strcmp(sr->name, "cpu-temp")) {
589 		if (wf_get_sensor(sr) == 0)
590 			sensor_cpu_temp = sr;
591 	}
592 
593 	if (sensor_hd_temp == NULL && !strcmp(sr->name, "hd-temp")) {
594 		if (wf_get_sensor(sr) == 0)
595 			sensor_hd_temp = sr;
596 	}
597 
598 	if (sensor_slots_power == NULL && !strcmp(sr->name, "slots-power")) {
599 		if (wf_get_sensor(sr) == 0)
600 			sensor_slots_power = sr;
601 	}
602 
603 	if (sensor_cpu_power && sensor_cpu_temp &&
604 	    sensor_hd_temp && sensor_slots_power)
605 		wf_smu_all_sensors_ok = 1;
606 }
607 
608 
609 static int wf_smu_notify(struct notifier_block *self,
610 			       unsigned long event, void *data)
611 {
612 	switch(event) {
613 	case WF_EVENT_NEW_CONTROL:
614 		DBG("wf: new control %s detected\n",
615 		    ((struct wf_control *)data)->name);
616 		wf_smu_new_control(data);
617 		wf_smu_readjust = 1;
618 		break;
619 	case WF_EVENT_NEW_SENSOR:
620 		DBG("wf: new sensor %s detected\n",
621 		    ((struct wf_sensor *)data)->name);
622 		wf_smu_new_sensor(data);
623 		break;
624 	case WF_EVENT_TICK:
625 		if (wf_smu_all_controls_ok && wf_smu_all_sensors_ok)
626 			wf_smu_tick();
627 	}
628 
629 	return 0;
630 }
631 
632 static struct notifier_block wf_smu_events = {
633 	.notifier_call	= wf_smu_notify,
634 };
635 
636 static int wf_init_pm(void)
637 {
638 	printk(KERN_INFO "windfarm: Initializing for Desktop G5 model\n");
639 
640 	return 0;
641 }
642 
643 static int wf_smu_probe(struct platform_device *ddev)
644 {
645 	wf_register_client(&wf_smu_events);
646 
647 	return 0;
648 }
649 
650 static int wf_smu_remove(struct platform_device *ddev)
651 {
652 	wf_unregister_client(&wf_smu_events);
653 
654 	/* XXX We don't have yet a guarantee that our callback isn't
655 	 * in progress when returning from wf_unregister_client, so
656 	 * we add an arbitrary delay. I'll have to fix that in the core
657 	 */
658 	msleep(1000);
659 
660 	/* Release all sensors */
661 	/* One more crappy race: I don't think we have any guarantee here
662 	 * that the attribute callback won't race with the sensor beeing
663 	 * disposed of, and I'm not 100% certain what best way to deal
664 	 * with that except by adding locks all over... I'll do that
665 	 * eventually but heh, who ever rmmod this module anyway ?
666 	 */
667 	if (sensor_cpu_power)
668 		wf_put_sensor(sensor_cpu_power);
669 	if (sensor_cpu_temp)
670 		wf_put_sensor(sensor_cpu_temp);
671 	if (sensor_hd_temp)
672 		wf_put_sensor(sensor_hd_temp);
673 	if (sensor_slots_power)
674 		wf_put_sensor(sensor_slots_power);
675 
676 	/* Release all controls */
677 	if (fan_cpu_main)
678 		wf_put_control(fan_cpu_main);
679 	if (fan_cpu_second)
680 		wf_put_control(fan_cpu_second);
681 	if (fan_cpu_third)
682 		wf_put_control(fan_cpu_third);
683 	if (fan_hd)
684 		wf_put_control(fan_hd);
685 	if (fan_slots)
686 		wf_put_control(fan_slots);
687 	if (cpufreq_clamp)
688 		wf_put_control(cpufreq_clamp);
689 
690 	/* Destroy control loops state structures */
691 	kfree(wf_smu_slots_fans);
692 	kfree(wf_smu_drive_fans);
693 	kfree(wf_smu_cpu_fans);
694 
695 	return 0;
696 }
697 
698 static struct platform_driver wf_smu_driver = {
699         .probe = wf_smu_probe,
700         .remove = wf_smu_remove,
701 	.driver = {
702 		.name = "windfarm",
703 	},
704 };
705 
706 
707 static int __init wf_smu_init(void)
708 {
709 	int rc = -ENODEV;
710 
711 	if (of_machine_is_compatible("PowerMac9,1"))
712 		rc = wf_init_pm();
713 
714 	if (rc == 0) {
715 #ifdef MODULE
716 		request_module("windfarm_smu_controls");
717 		request_module("windfarm_smu_sensors");
718 		request_module("windfarm_lm75_sensor");
719 		request_module("windfarm_cpufreq_clamp");
720 
721 #endif /* MODULE */
722 		platform_driver_register(&wf_smu_driver);
723 	}
724 
725 	return rc;
726 }
727 
728 static void __exit wf_smu_exit(void)
729 {
730 
731 	platform_driver_unregister(&wf_smu_driver);
732 }
733 
734 
735 module_init(wf_smu_init);
736 module_exit(wf_smu_exit);
737 
738 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
739 MODULE_DESCRIPTION("Thermal control logic for PowerMac9,1");
740 MODULE_LICENSE("GPL");
741 
742 MODULE_ALIAS("platform:windfarm");
743