xref: /openbmc/linux/drivers/hwmon/nzxt-smart2.c (revision 2a598d0b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Reverse-engineered NZXT RGB & Fan Controller/Smart Device v2 driver.
4  *
5  * Copyright (c) 2021 Aleksandr Mezin
6  */
7 
8 #include <linux/hid.h>
9 #include <linux/hwmon.h>
10 #include <linux/math.h>
11 #include <linux/module.h>
12 #include <linux/mutex.h>
13 #include <linux/spinlock.h>
14 #include <linux/wait.h>
15 
16 #include <asm/byteorder.h>
17 #include <asm/unaligned.h>
18 
19 /*
20  * The device has only 3 fan channels/connectors. But all HID reports have
21  * space reserved for up to 8 channels.
22  */
23 #define FAN_CHANNELS 3
24 #define FAN_CHANNELS_MAX 8
25 
26 #define UPDATE_INTERVAL_DEFAULT_MS 1000
27 
28 /* These strings match labels on the device exactly */
29 static const char *const fan_label[] = {
30 	"FAN 1",
31 	"FAN 2",
32 	"FAN 3",
33 };
34 
35 static const char *const curr_label[] = {
36 	"FAN 1 Current",
37 	"FAN 2 Current",
38 	"FAN 3 Current",
39 };
40 
41 static const char *const in_label[] = {
42 	"FAN 1 Voltage",
43 	"FAN 2 Voltage",
44 	"FAN 3 Voltage",
45 };
46 
47 enum {
48 	INPUT_REPORT_ID_FAN_CONFIG = 0x61,
49 	INPUT_REPORT_ID_FAN_STATUS = 0x67,
50 };
51 
52 enum {
53 	FAN_STATUS_REPORT_SPEED = 0x02,
54 	FAN_STATUS_REPORT_VOLTAGE = 0x04,
55 };
56 
57 enum {
58 	FAN_TYPE_NONE = 0,
59 	FAN_TYPE_DC = 1,
60 	FAN_TYPE_PWM = 2,
61 };
62 
63 struct unknown_static_data {
64 	/*
65 	 * Some configuration data? Stays the same after fan speed changes,
66 	 * changes in fan configuration, reboots and driver reloads.
67 	 *
68 	 * The same data in multiple report types.
69 	 *
70 	 * Byte 12 seems to be the number of fan channels, but I am not sure.
71 	 */
72 	u8 unknown1[14];
73 } __packed;
74 
75 /*
76  * The device sends this input report in response to "detect fans" command:
77  * a 2-byte output report { 0x60, 0x03 }.
78  */
79 struct fan_config_report {
80 	/* report_id should be INPUT_REPORT_ID_FAN_CONFIG = 0x61 */
81 	u8 report_id;
82 	/* Always 0x03 */
83 	u8 magic;
84 	struct unknown_static_data unknown_data;
85 	/* Fan type as detected by the device. See FAN_TYPE_* enum. */
86 	u8 fan_type[FAN_CHANNELS_MAX];
87 } __packed;
88 
89 /*
90  * The device sends these reports at a fixed interval (update interval) -
91  * one report with type = FAN_STATUS_REPORT_SPEED, and one report with type =
92  * FAN_STATUS_REPORT_VOLTAGE per update interval.
93  */
94 struct fan_status_report {
95 	/* report_id should be INPUT_REPORT_ID_STATUS = 0x67 */
96 	u8 report_id;
97 	/* FAN_STATUS_REPORT_SPEED = 0x02 or FAN_STATUS_REPORT_VOLTAGE = 0x04 */
98 	u8 type;
99 	struct unknown_static_data unknown_data;
100 	/* Fan type as detected by the device. See FAN_TYPE_* enum. */
101 	u8 fan_type[FAN_CHANNELS_MAX];
102 
103 	union {
104 		/* When type == FAN_STATUS_REPORT_SPEED */
105 		struct {
106 			/*
107 			 * Fan speed, in RPM. Zero for channels without fans
108 			 * connected.
109 			 */
110 			__le16 fan_rpm[FAN_CHANNELS_MAX];
111 			/*
112 			 * Fan duty cycle, in percent. Non-zero even for
113 			 * channels without fans connected.
114 			 */
115 			u8 duty_percent[FAN_CHANNELS_MAX];
116 			/*
117 			 * Exactly the same values as duty_percent[], non-zero
118 			 * for disconnected fans too.
119 			 */
120 			u8 duty_percent_dup[FAN_CHANNELS_MAX];
121 			/* "Case Noise" in db */
122 			u8 noise_db;
123 		} __packed fan_speed;
124 		/* When type == FAN_STATUS_REPORT_VOLTAGE */
125 		struct {
126 			/*
127 			 * Voltage, in millivolts. Non-zero even when fan is
128 			 * not connected.
129 			 */
130 			__le16 fan_in[FAN_CHANNELS_MAX];
131 			/*
132 			 * Current, in milliamperes. Near-zero when
133 			 * disconnected.
134 			 */
135 			__le16 fan_current[FAN_CHANNELS_MAX];
136 		} __packed fan_voltage;
137 	} __packed;
138 } __packed;
139 
140 #define OUTPUT_REPORT_SIZE 64
141 
142 enum {
143 	OUTPUT_REPORT_ID_INIT_COMMAND = 0x60,
144 	OUTPUT_REPORT_ID_SET_FAN_SPEED = 0x62,
145 };
146 
147 enum {
148 	INIT_COMMAND_SET_UPDATE_INTERVAL = 0x02,
149 	INIT_COMMAND_DETECT_FANS = 0x03,
150 };
151 
152 /*
153  * This output report sets pwm duty cycle/target fan speed for one or more
154  * channels.
155  */
156 struct set_fan_speed_report {
157 	/* report_id should be OUTPUT_REPORT_ID_SET_FAN_SPEED = 0x62 */
158 	u8 report_id;
159 	/* Should be 0x01 */
160 	u8 magic;
161 	/* To change fan speed on i-th channel, set i-th bit here */
162 	u8 channel_bit_mask;
163 	/*
164 	 * Fan duty cycle/target speed in percent. For voltage-controlled fans,
165 	 * the minimal voltage (duty_percent = 1) is about 9V.
166 	 * Setting duty_percent to 0 (if the channel is selected in
167 	 * channel_bit_mask) turns off the fan completely (regardless of the
168 	 * control mode).
169 	 */
170 	u8 duty_percent[FAN_CHANNELS_MAX];
171 } __packed;
172 
173 struct drvdata {
174 	struct hid_device *hid;
175 	struct device *hwmon;
176 
177 	u8 fan_duty_percent[FAN_CHANNELS];
178 	u16 fan_rpm[FAN_CHANNELS];
179 	bool pwm_status_received;
180 
181 	u16 fan_in[FAN_CHANNELS];
182 	u16 fan_curr[FAN_CHANNELS];
183 	bool voltage_status_received;
184 
185 	u8 fan_type[FAN_CHANNELS];
186 	bool fan_config_received;
187 
188 	/*
189 	 * wq is used to wait for *_received flags to become true.
190 	 * All accesses to *_received flags and fan_* arrays are performed with
191 	 * wq.lock held.
192 	 */
193 	wait_queue_head_t wq;
194 	/*
195 	 * mutex is used to:
196 	 * 1) Prevent concurrent conflicting changes to update interval and pwm
197 	 * values (after sending an output hid report, the corresponding field
198 	 * in drvdata must be updated, and only then new output reports can be
199 	 * sent).
200 	 * 2) Synchronize access to output_buffer (well, the buffer is here,
201 	 * because synchronization is necessary anyway - so why not get rid of
202 	 * a kmalloc?).
203 	 */
204 	struct mutex mutex;
205 	long update_interval;
206 	u8 output_buffer[OUTPUT_REPORT_SIZE];
207 };
208 
209 static long scale_pwm_value(long val, long orig_max, long new_max)
210 {
211 	if (val <= 0)
212 		return 0;
213 
214 	/*
215 	 * Positive values should not become zero: 0 completely turns off the
216 	 * fan.
217 	 */
218 	return max(1L, DIV_ROUND_CLOSEST(min(val, orig_max) * new_max, orig_max));
219 }
220 
221 static void handle_fan_config_report(struct drvdata *drvdata, void *data, int size)
222 {
223 	struct fan_config_report *report = data;
224 	int i;
225 
226 	if (size < sizeof(struct fan_config_report))
227 		return;
228 
229 	if (report->magic != 0x03)
230 		return;
231 
232 	spin_lock(&drvdata->wq.lock);
233 
234 	for (i = 0; i < FAN_CHANNELS; i++)
235 		drvdata->fan_type[i] = report->fan_type[i];
236 
237 	drvdata->fan_config_received = true;
238 	wake_up_all_locked(&drvdata->wq);
239 	spin_unlock(&drvdata->wq.lock);
240 }
241 
242 static void handle_fan_status_report(struct drvdata *drvdata, void *data, int size)
243 {
244 	struct fan_status_report *report = data;
245 	int i;
246 
247 	if (size < sizeof(struct fan_status_report))
248 		return;
249 
250 	spin_lock(&drvdata->wq.lock);
251 
252 	/*
253 	 * The device sends INPUT_REPORT_ID_FAN_CONFIG = 0x61 report in response
254 	 * to "detect fans" command. Only accept other data after getting 0x61,
255 	 * to make sure that fan detection is complete. In particular, fan
256 	 * detection resets pwm values.
257 	 */
258 	if (!drvdata->fan_config_received) {
259 		spin_unlock(&drvdata->wq.lock);
260 		return;
261 	}
262 
263 	for (i = 0; i < FAN_CHANNELS; i++) {
264 		if (drvdata->fan_type[i] == report->fan_type[i])
265 			continue;
266 
267 		/*
268 		 * This should not happen (if my expectations about the device
269 		 * are correct).
270 		 *
271 		 * Even if the userspace sends fan detect command through
272 		 * hidraw, fan config report should arrive first.
273 		 */
274 		hid_warn_once(drvdata->hid,
275 			      "Fan %d type changed unexpectedly from %d to %d",
276 			      i, drvdata->fan_type[i], report->fan_type[i]);
277 		drvdata->fan_type[i] = report->fan_type[i];
278 	}
279 
280 	switch (report->type) {
281 	case FAN_STATUS_REPORT_SPEED:
282 		for (i = 0; i < FAN_CHANNELS; i++) {
283 			drvdata->fan_rpm[i] =
284 				get_unaligned_le16(&report->fan_speed.fan_rpm[i]);
285 			drvdata->fan_duty_percent[i] =
286 				report->fan_speed.duty_percent[i];
287 		}
288 
289 		drvdata->pwm_status_received = true;
290 		wake_up_all_locked(&drvdata->wq);
291 		break;
292 
293 	case FAN_STATUS_REPORT_VOLTAGE:
294 		for (i = 0; i < FAN_CHANNELS; i++) {
295 			drvdata->fan_in[i] =
296 				get_unaligned_le16(&report->fan_voltage.fan_in[i]);
297 			drvdata->fan_curr[i] =
298 				get_unaligned_le16(&report->fan_voltage.fan_current[i]);
299 		}
300 
301 		drvdata->voltage_status_received = true;
302 		wake_up_all_locked(&drvdata->wq);
303 		break;
304 	}
305 
306 	spin_unlock(&drvdata->wq.lock);
307 }
308 
309 static umode_t nzxt_smart2_hwmon_is_visible(const void *data,
310 					    enum hwmon_sensor_types type,
311 					    u32 attr, int channel)
312 {
313 	switch (type) {
314 	case hwmon_pwm:
315 		switch (attr) {
316 		case hwmon_pwm_input:
317 		case hwmon_pwm_enable:
318 			return 0644;
319 
320 		default:
321 			return 0444;
322 		}
323 
324 	case hwmon_chip:
325 		switch (attr) {
326 		case hwmon_chip_update_interval:
327 			return 0644;
328 
329 		default:
330 			return 0444;
331 		}
332 
333 	default:
334 		return 0444;
335 	}
336 }
337 
338 static int nzxt_smart2_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
339 				  u32 attr, int channel, long *val)
340 {
341 	struct drvdata *drvdata = dev_get_drvdata(dev);
342 	int res = -EINVAL;
343 
344 	if (type == hwmon_chip) {
345 		switch (attr) {
346 		case hwmon_chip_update_interval:
347 			*val = drvdata->update_interval;
348 			return 0;
349 
350 		default:
351 			return -EINVAL;
352 		}
353 	}
354 
355 	spin_lock_irq(&drvdata->wq.lock);
356 
357 	switch (type) {
358 	case hwmon_pwm:
359 		/*
360 		 * fancontrol:
361 		 * 1) remembers pwm* values when it starts
362 		 * 2) needs pwm*_enable to be 1 on controlled fans
363 		 * So make sure we have correct data before allowing pwm* reads.
364 		 * Returning errors for pwm of fan speed read can even cause
365 		 * fancontrol to shut down. So the wait is unavoidable.
366 		 */
367 		switch (attr) {
368 		case hwmon_pwm_enable:
369 			res = wait_event_interruptible_locked_irq(drvdata->wq,
370 								  drvdata->fan_config_received);
371 			if (res)
372 				goto unlock;
373 
374 			*val = drvdata->fan_type[channel] != FAN_TYPE_NONE;
375 			break;
376 
377 		case hwmon_pwm_mode:
378 			res = wait_event_interruptible_locked_irq(drvdata->wq,
379 								  drvdata->fan_config_received);
380 			if (res)
381 				goto unlock;
382 
383 			*val = drvdata->fan_type[channel] == FAN_TYPE_PWM;
384 			break;
385 
386 		case hwmon_pwm_input:
387 			res = wait_event_interruptible_locked_irq(drvdata->wq,
388 								  drvdata->pwm_status_received);
389 			if (res)
390 				goto unlock;
391 
392 			*val = scale_pwm_value(drvdata->fan_duty_percent[channel],
393 					       100, 255);
394 			break;
395 		}
396 		break;
397 
398 	case hwmon_fan:
399 		/*
400 		 * It's not strictly necessary to wait for *_received in the
401 		 * remaining cases (fancontrol doesn't care about them). But I'm
402 		 * doing it to have consistent behavior.
403 		 */
404 		if (attr == hwmon_fan_input) {
405 			res = wait_event_interruptible_locked_irq(drvdata->wq,
406 								  drvdata->pwm_status_received);
407 			if (res)
408 				goto unlock;
409 
410 			*val = drvdata->fan_rpm[channel];
411 		}
412 		break;
413 
414 	case hwmon_in:
415 		if (attr == hwmon_in_input) {
416 			res = wait_event_interruptible_locked_irq(drvdata->wq,
417 								  drvdata->voltage_status_received);
418 			if (res)
419 				goto unlock;
420 
421 			*val = drvdata->fan_in[channel];
422 		}
423 		break;
424 
425 	case hwmon_curr:
426 		if (attr == hwmon_curr_input) {
427 			res = wait_event_interruptible_locked_irq(drvdata->wq,
428 								  drvdata->voltage_status_received);
429 			if (res)
430 				goto unlock;
431 
432 			*val = drvdata->fan_curr[channel];
433 		}
434 		break;
435 
436 	default:
437 		break;
438 	}
439 
440 unlock:
441 	spin_unlock_irq(&drvdata->wq.lock);
442 	return res;
443 }
444 
445 static int send_output_report(struct drvdata *drvdata, const void *data,
446 			      size_t data_size)
447 {
448 	int ret;
449 
450 	if (data_size > sizeof(drvdata->output_buffer))
451 		return -EINVAL;
452 
453 	memcpy(drvdata->output_buffer, data, data_size);
454 
455 	if (data_size < sizeof(drvdata->output_buffer))
456 		memset(drvdata->output_buffer + data_size, 0,
457 		       sizeof(drvdata->output_buffer) - data_size);
458 
459 	ret = hid_hw_output_report(drvdata->hid, drvdata->output_buffer,
460 				   sizeof(drvdata->output_buffer));
461 	return ret < 0 ? ret : 0;
462 }
463 
464 static int set_pwm(struct drvdata *drvdata, int channel, long val)
465 {
466 	int ret;
467 	u8 duty_percent = scale_pwm_value(val, 255, 100);
468 
469 	struct set_fan_speed_report report = {
470 		.report_id = OUTPUT_REPORT_ID_SET_FAN_SPEED,
471 		.magic = 1,
472 		.channel_bit_mask = 1 << channel
473 	};
474 
475 	ret = mutex_lock_interruptible(&drvdata->mutex);
476 	if (ret)
477 		return ret;
478 
479 	report.duty_percent[channel] = duty_percent;
480 	ret = send_output_report(drvdata, &report, sizeof(report));
481 	if (ret)
482 		goto unlock;
483 
484 	/*
485 	 * pwmconfig and fancontrol scripts expect pwm writes to take effect
486 	 * immediately (i. e. read from pwm* sysfs should return the value
487 	 * written into it). The device seems to always accept pwm values - even
488 	 * when there is no fan connected - so update pwm status without waiting
489 	 * for a report, to make pwmconfig and fancontrol happy. Worst case -
490 	 * if the device didn't accept new pwm value for some reason (never seen
491 	 * this in practice) - it will be reported incorrectly only until next
492 	 * update. This avoids "fan stuck" messages from pwmconfig, and
493 	 * fancontrol setting fan speed to 100% during shutdown.
494 	 */
495 	spin_lock_bh(&drvdata->wq.lock);
496 	drvdata->fan_duty_percent[channel] = duty_percent;
497 	spin_unlock_bh(&drvdata->wq.lock);
498 
499 unlock:
500 	mutex_unlock(&drvdata->mutex);
501 	return ret;
502 }
503 
504 /*
505  * Workaround for fancontrol/pwmconfig trying to write to pwm*_enable even if it
506  * already is 1 and read-only. Otherwise, fancontrol won't restore pwm on
507  * shutdown properly.
508  */
509 static int set_pwm_enable(struct drvdata *drvdata, int channel, long val)
510 {
511 	long expected_val;
512 	int res;
513 
514 	spin_lock_irq(&drvdata->wq.lock);
515 
516 	res = wait_event_interruptible_locked_irq(drvdata->wq,
517 						  drvdata->fan_config_received);
518 	if (res) {
519 		spin_unlock_irq(&drvdata->wq.lock);
520 		return res;
521 	}
522 
523 	expected_val = drvdata->fan_type[channel] != FAN_TYPE_NONE;
524 
525 	spin_unlock_irq(&drvdata->wq.lock);
526 
527 	return (val == expected_val) ? 0 : -EOPNOTSUPP;
528 }
529 
530 /*
531  * Control byte	| Actual update interval in seconds
532  * 0xff		| 65.5
533  * 0xf7		| 63.46
534  * 0x7f		| 32.74
535  * 0x3f		| 16.36
536  * 0x1f		| 8.17
537  * 0x0f		| 4.07
538  * 0x07		| 2.02
539  * 0x03		| 1.00
540  * 0x02		| 0.744
541  * 0x01		| 0.488
542  * 0x00		| 0.25
543  */
544 static u8 update_interval_to_control_byte(long interval)
545 {
546 	if (interval <= 250)
547 		return 0;
548 
549 	return clamp_val(1 + DIV_ROUND_CLOSEST(interval - 488, 256), 0, 255);
550 }
551 
552 static long control_byte_to_update_interval(u8 control_byte)
553 {
554 	if (control_byte == 0)
555 		return 250;
556 
557 	return 488 + (control_byte - 1) * 256;
558 }
559 
560 static int set_update_interval(struct drvdata *drvdata, long val)
561 {
562 	u8 control = update_interval_to_control_byte(val);
563 	u8 report[] = {
564 		OUTPUT_REPORT_ID_INIT_COMMAND,
565 		INIT_COMMAND_SET_UPDATE_INTERVAL,
566 		0x01,
567 		0xe8,
568 		control,
569 		0x01,
570 		0xe8,
571 		control,
572 	};
573 	int ret;
574 
575 	ret = send_output_report(drvdata, report, sizeof(report));
576 	if (ret)
577 		return ret;
578 
579 	drvdata->update_interval = control_byte_to_update_interval(control);
580 	return 0;
581 }
582 
583 static int init_device(struct drvdata *drvdata, long update_interval)
584 {
585 	int ret;
586 	static const u8 detect_fans_report[] = {
587 		OUTPUT_REPORT_ID_INIT_COMMAND,
588 		INIT_COMMAND_DETECT_FANS,
589 	};
590 
591 	ret = send_output_report(drvdata, detect_fans_report,
592 				 sizeof(detect_fans_report));
593 	if (ret)
594 		return ret;
595 
596 	return set_update_interval(drvdata, update_interval);
597 }
598 
599 static int nzxt_smart2_hwmon_write(struct device *dev,
600 				   enum hwmon_sensor_types type, u32 attr,
601 				   int channel, long val)
602 {
603 	struct drvdata *drvdata = dev_get_drvdata(dev);
604 	int ret;
605 
606 	switch (type) {
607 	case hwmon_pwm:
608 		switch (attr) {
609 		case hwmon_pwm_enable:
610 			return set_pwm_enable(drvdata, channel, val);
611 
612 		case hwmon_pwm_input:
613 			return set_pwm(drvdata, channel, val);
614 
615 		default:
616 			return -EINVAL;
617 		}
618 
619 	case hwmon_chip:
620 		switch (attr) {
621 		case hwmon_chip_update_interval:
622 			ret = mutex_lock_interruptible(&drvdata->mutex);
623 			if (ret)
624 				return ret;
625 
626 			ret = set_update_interval(drvdata, val);
627 
628 			mutex_unlock(&drvdata->mutex);
629 			return ret;
630 
631 		default:
632 			return -EINVAL;
633 		}
634 
635 	default:
636 		return -EINVAL;
637 	}
638 }
639 
640 static int nzxt_smart2_hwmon_read_string(struct device *dev,
641 					 enum hwmon_sensor_types type, u32 attr,
642 					 int channel, const char **str)
643 {
644 	switch (type) {
645 	case hwmon_fan:
646 		*str = fan_label[channel];
647 		return 0;
648 	case hwmon_curr:
649 		*str = curr_label[channel];
650 		return 0;
651 	case hwmon_in:
652 		*str = in_label[channel];
653 		return 0;
654 	default:
655 		return -EINVAL;
656 	}
657 }
658 
659 static const struct hwmon_ops nzxt_smart2_hwmon_ops = {
660 	.is_visible = nzxt_smart2_hwmon_is_visible,
661 	.read = nzxt_smart2_hwmon_read,
662 	.read_string = nzxt_smart2_hwmon_read_string,
663 	.write = nzxt_smart2_hwmon_write,
664 };
665 
666 static const struct hwmon_channel_info * const nzxt_smart2_channel_info[] = {
667 	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_LABEL,
668 			   HWMON_F_INPUT | HWMON_F_LABEL,
669 			   HWMON_F_INPUT | HWMON_F_LABEL),
670 	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_MODE | HWMON_PWM_ENABLE,
671 			   HWMON_PWM_INPUT | HWMON_PWM_MODE | HWMON_PWM_ENABLE,
672 			   HWMON_PWM_INPUT | HWMON_PWM_MODE | HWMON_PWM_ENABLE),
673 	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LABEL,
674 			   HWMON_I_INPUT | HWMON_I_LABEL,
675 			   HWMON_I_INPUT | HWMON_I_LABEL),
676 	HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT | HWMON_C_LABEL,
677 			   HWMON_C_INPUT | HWMON_C_LABEL,
678 			   HWMON_C_INPUT | HWMON_C_LABEL),
679 	HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
680 	NULL
681 };
682 
683 static const struct hwmon_chip_info nzxt_smart2_chip_info = {
684 	.ops = &nzxt_smart2_hwmon_ops,
685 	.info = nzxt_smart2_channel_info,
686 };
687 
688 static int nzxt_smart2_hid_raw_event(struct hid_device *hdev,
689 				     struct hid_report *report, u8 *data, int size)
690 {
691 	struct drvdata *drvdata = hid_get_drvdata(hdev);
692 	u8 report_id = *data;
693 
694 	switch (report_id) {
695 	case INPUT_REPORT_ID_FAN_CONFIG:
696 		handle_fan_config_report(drvdata, data, size);
697 		break;
698 
699 	case INPUT_REPORT_ID_FAN_STATUS:
700 		handle_fan_status_report(drvdata, data, size);
701 		break;
702 	}
703 
704 	return 0;
705 }
706 
707 static int __maybe_unused nzxt_smart2_hid_reset_resume(struct hid_device *hdev)
708 {
709 	struct drvdata *drvdata = hid_get_drvdata(hdev);
710 
711 	/*
712 	 * Userspace is still frozen (so no concurrent sysfs attribute access
713 	 * is possible), but raw_event can already be called concurrently.
714 	 */
715 	spin_lock_bh(&drvdata->wq.lock);
716 	drvdata->fan_config_received = false;
717 	drvdata->pwm_status_received = false;
718 	drvdata->voltage_status_received = false;
719 	spin_unlock_bh(&drvdata->wq.lock);
720 
721 	return init_device(drvdata, drvdata->update_interval);
722 }
723 
724 static void mutex_fini(void *lock)
725 {
726 	mutex_destroy(lock);
727 }
728 
729 static int nzxt_smart2_hid_probe(struct hid_device *hdev,
730 				 const struct hid_device_id *id)
731 {
732 	struct drvdata *drvdata;
733 	int ret;
734 
735 	drvdata = devm_kzalloc(&hdev->dev, sizeof(struct drvdata), GFP_KERNEL);
736 	if (!drvdata)
737 		return -ENOMEM;
738 
739 	drvdata->hid = hdev;
740 	hid_set_drvdata(hdev, drvdata);
741 
742 	init_waitqueue_head(&drvdata->wq);
743 
744 	mutex_init(&drvdata->mutex);
745 	ret = devm_add_action_or_reset(&hdev->dev, mutex_fini, &drvdata->mutex);
746 	if (ret)
747 		return ret;
748 
749 	ret = hid_parse(hdev);
750 	if (ret)
751 		return ret;
752 
753 	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
754 	if (ret)
755 		return ret;
756 
757 	ret = hid_hw_open(hdev);
758 	if (ret)
759 		goto out_hw_stop;
760 
761 	hid_device_io_start(hdev);
762 
763 	init_device(drvdata, UPDATE_INTERVAL_DEFAULT_MS);
764 
765 	drvdata->hwmon =
766 		hwmon_device_register_with_info(&hdev->dev, "nzxtsmart2", drvdata,
767 						&nzxt_smart2_chip_info, NULL);
768 	if (IS_ERR(drvdata->hwmon)) {
769 		ret = PTR_ERR(drvdata->hwmon);
770 		goto out_hw_close;
771 	}
772 
773 	return 0;
774 
775 out_hw_close:
776 	hid_hw_close(hdev);
777 
778 out_hw_stop:
779 	hid_hw_stop(hdev);
780 	return ret;
781 }
782 
783 static void nzxt_smart2_hid_remove(struct hid_device *hdev)
784 {
785 	struct drvdata *drvdata = hid_get_drvdata(hdev);
786 
787 	hwmon_device_unregister(drvdata->hwmon);
788 
789 	hid_hw_close(hdev);
790 	hid_hw_stop(hdev);
791 }
792 
793 static const struct hid_device_id nzxt_smart2_hid_id_table[] = {
794 	{ HID_USB_DEVICE(0x1e71, 0x2006) }, /* NZXT Smart Device V2 */
795 	{ HID_USB_DEVICE(0x1e71, 0x200d) }, /* NZXT Smart Device V2 */
796 	{ HID_USB_DEVICE(0x1e71, 0x200f) }, /* NZXT Smart Device V2 */
797 	{ HID_USB_DEVICE(0x1e71, 0x2009) }, /* NZXT RGB & Fan Controller */
798 	{ HID_USB_DEVICE(0x1e71, 0x200e) }, /* NZXT RGB & Fan Controller */
799 	{ HID_USB_DEVICE(0x1e71, 0x2010) }, /* NZXT RGB & Fan Controller */
800 	{ HID_USB_DEVICE(0x1e71, 0x2011) }, /* NZXT RGB & Fan Controller (6 RGB) */
801 	{ HID_USB_DEVICE(0x1e71, 0x2019) }, /* NZXT RGB & Fan Controller (6 RGB) */
802 	{},
803 };
804 
805 static struct hid_driver nzxt_smart2_hid_driver = {
806 	.name = "nzxt-smart2",
807 	.id_table = nzxt_smart2_hid_id_table,
808 	.probe = nzxt_smart2_hid_probe,
809 	.remove = nzxt_smart2_hid_remove,
810 	.raw_event = nzxt_smart2_hid_raw_event,
811 #ifdef CONFIG_PM
812 	.reset_resume = nzxt_smart2_hid_reset_resume,
813 #endif
814 };
815 
816 static int __init nzxt_smart2_init(void)
817 {
818 	return hid_register_driver(&nzxt_smart2_hid_driver);
819 }
820 
821 static void __exit nzxt_smart2_exit(void)
822 {
823 	hid_unregister_driver(&nzxt_smart2_hid_driver);
824 }
825 
826 MODULE_DEVICE_TABLE(hid, nzxt_smart2_hid_id_table);
827 MODULE_AUTHOR("Aleksandr Mezin <mezin.alexander@gmail.com>");
828 MODULE_DESCRIPTION("Driver for NZXT RGB & Fan Controller/Smart Device V2");
829 MODULE_LICENSE("GPL");
830 
831 /*
832  * With module_init()/module_hid_driver() and the driver built into the kernel:
833  *
834  * Driver 'nzxt_smart2' was unable to register with bus_type 'hid' because the
835  * bus was not initialized.
836  */
837 late_initcall(nzxt_smart2_init);
838 module_exit(nzxt_smart2_exit);
839