1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
4  *
5  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
6  *
7  * Hwmon integration:
8  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
9  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
10  * Copyright (C) 2014, 2015  Pali Rohár <pali.rohar@gmail.com>
11  */
12 
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 
15 #include <linux/cpu.h>
16 #include <linux/delay.h>
17 #include <linux/module.h>
18 #include <linux/types.h>
19 #include <linux/init.h>
20 #include <linux/proc_fs.h>
21 #include <linux/seq_file.h>
22 #include <linux/dmi.h>
23 #include <linux/capability.h>
24 #include <linux/mutex.h>
25 #include <linux/hwmon.h>
26 #include <linux/hwmon-sysfs.h>
27 #include <linux/uaccess.h>
28 #include <linux/io.h>
29 #include <linux/sched.h>
30 #include <linux/ctype.h>
31 #include <linux/smp.h>
32 
33 #include <linux/i8k.h>
34 
35 #define I8K_SMM_FN_STATUS	0x0025
36 #define I8K_SMM_POWER_STATUS	0x0069
37 #define I8K_SMM_SET_FAN		0x01a3
38 #define I8K_SMM_GET_FAN		0x00a3
39 #define I8K_SMM_GET_SPEED	0x02a3
40 #define I8K_SMM_GET_FAN_TYPE	0x03a3
41 #define I8K_SMM_GET_NOM_SPEED	0x04a3
42 #define I8K_SMM_GET_TEMP	0x10a3
43 #define I8K_SMM_GET_TEMP_TYPE	0x11a3
44 #define I8K_SMM_GET_DELL_SIG1	0xfea3
45 #define I8K_SMM_GET_DELL_SIG2	0xffa3
46 
47 #define I8K_FAN_MULT		30
48 #define I8K_FAN_MAX_RPM		30000
49 #define I8K_MAX_TEMP		127
50 
51 #define I8K_FN_NONE		0x00
52 #define I8K_FN_UP		0x01
53 #define I8K_FN_DOWN		0x02
54 #define I8K_FN_MUTE		0x04
55 #define I8K_FN_MASK		0x07
56 #define I8K_FN_SHIFT		8
57 
58 #define I8K_POWER_AC		0x05
59 #define I8K_POWER_BATTERY	0x01
60 
61 static DEFINE_MUTEX(i8k_mutex);
62 static char bios_version[4];
63 static char bios_machineid[16];
64 static struct device *i8k_hwmon_dev;
65 static u32 i8k_hwmon_flags;
66 static uint i8k_fan_mult = I8K_FAN_MULT;
67 static uint i8k_pwm_mult;
68 static uint i8k_fan_max = I8K_FAN_HIGH;
69 static bool disallow_fan_type_call;
70 static bool disallow_fan_support;
71 static unsigned int manual_fan;
72 static unsigned int auto_fan;
73 
74 #define I8K_HWMON_HAVE_TEMP1	(1 << 0)
75 #define I8K_HWMON_HAVE_TEMP2	(1 << 1)
76 #define I8K_HWMON_HAVE_TEMP3	(1 << 2)
77 #define I8K_HWMON_HAVE_TEMP4	(1 << 3)
78 #define I8K_HWMON_HAVE_TEMP5	(1 << 4)
79 #define I8K_HWMON_HAVE_TEMP6	(1 << 5)
80 #define I8K_HWMON_HAVE_TEMP7	(1 << 6)
81 #define I8K_HWMON_HAVE_TEMP8	(1 << 7)
82 #define I8K_HWMON_HAVE_TEMP9	(1 << 8)
83 #define I8K_HWMON_HAVE_TEMP10	(1 << 9)
84 #define I8K_HWMON_HAVE_FAN1	(1 << 10)
85 #define I8K_HWMON_HAVE_FAN2	(1 << 11)
86 #define I8K_HWMON_HAVE_FAN3	(1 << 12)
87 
88 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
89 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
90 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
91 MODULE_LICENSE("GPL");
92 MODULE_ALIAS("i8k");
93 
94 static bool force;
95 module_param(force, bool, 0);
96 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
97 
98 static bool ignore_dmi;
99 module_param(ignore_dmi, bool, 0);
100 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
101 
102 #if IS_ENABLED(CONFIG_I8K)
103 static bool restricted = true;
104 module_param(restricted, bool, 0);
105 MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");
106 
107 static bool power_status;
108 module_param(power_status, bool, 0600);
109 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
110 #endif
111 
112 static uint fan_mult;
113 module_param(fan_mult, uint, 0);
114 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
115 
116 static uint fan_max;
117 module_param(fan_max, uint, 0);
118 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
119 
120 struct smm_regs {
121 	unsigned int eax;
122 	unsigned int ebx __packed;
123 	unsigned int ecx __packed;
124 	unsigned int edx __packed;
125 	unsigned int esi __packed;
126 	unsigned int edi __packed;
127 };
128 
129 static inline const char *i8k_get_dmi_data(int field)
130 {
131 	const char *dmi_data = dmi_get_system_info(field);
132 
133 	return dmi_data && *dmi_data ? dmi_data : "?";
134 }
135 
136 /*
137  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
138  */
139 static int i8k_smm_func(void *par)
140 {
141 	int rc;
142 	struct smm_regs *regs = par;
143 	int eax = regs->eax;
144 
145 #ifdef DEBUG
146 	int ebx = regs->ebx;
147 	unsigned long duration;
148 	ktime_t calltime, delta, rettime;
149 
150 	calltime = ktime_get();
151 #endif
152 
153 	/* SMM requires CPU 0 */
154 	if (smp_processor_id() != 0)
155 		return -EBUSY;
156 
157 #if defined(CONFIG_X86_64)
158 	asm volatile("pushq %%rax\n\t"
159 		"movl 0(%%rax),%%edx\n\t"
160 		"pushq %%rdx\n\t"
161 		"movl 4(%%rax),%%ebx\n\t"
162 		"movl 8(%%rax),%%ecx\n\t"
163 		"movl 12(%%rax),%%edx\n\t"
164 		"movl 16(%%rax),%%esi\n\t"
165 		"movl 20(%%rax),%%edi\n\t"
166 		"popq %%rax\n\t"
167 		"out %%al,$0xb2\n\t"
168 		"out %%al,$0x84\n\t"
169 		"xchgq %%rax,(%%rsp)\n\t"
170 		"movl %%ebx,4(%%rax)\n\t"
171 		"movl %%ecx,8(%%rax)\n\t"
172 		"movl %%edx,12(%%rax)\n\t"
173 		"movl %%esi,16(%%rax)\n\t"
174 		"movl %%edi,20(%%rax)\n\t"
175 		"popq %%rdx\n\t"
176 		"movl %%edx,0(%%rax)\n\t"
177 		"pushfq\n\t"
178 		"popq %%rax\n\t"
179 		"andl $1,%%eax\n"
180 		: "=a"(rc)
181 		:    "a"(regs)
182 		:    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
183 #else
184 	asm volatile("pushl %%eax\n\t"
185 	    "movl 0(%%eax),%%edx\n\t"
186 	    "push %%edx\n\t"
187 	    "movl 4(%%eax),%%ebx\n\t"
188 	    "movl 8(%%eax),%%ecx\n\t"
189 	    "movl 12(%%eax),%%edx\n\t"
190 	    "movl 16(%%eax),%%esi\n\t"
191 	    "movl 20(%%eax),%%edi\n\t"
192 	    "popl %%eax\n\t"
193 	    "out %%al,$0xb2\n\t"
194 	    "out %%al,$0x84\n\t"
195 	    "xchgl %%eax,(%%esp)\n\t"
196 	    "movl %%ebx,4(%%eax)\n\t"
197 	    "movl %%ecx,8(%%eax)\n\t"
198 	    "movl %%edx,12(%%eax)\n\t"
199 	    "movl %%esi,16(%%eax)\n\t"
200 	    "movl %%edi,20(%%eax)\n\t"
201 	    "popl %%edx\n\t"
202 	    "movl %%edx,0(%%eax)\n\t"
203 	    "lahf\n\t"
204 	    "shrl $8,%%eax\n\t"
205 	    "andl $1,%%eax\n"
206 	    : "=a"(rc)
207 	    :    "a"(regs)
208 	    :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
209 #endif
210 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
211 		rc = -EINVAL;
212 
213 #ifdef DEBUG
214 	rettime = ktime_get();
215 	delta = ktime_sub(rettime, calltime);
216 	duration = ktime_to_ns(delta) >> 10;
217 	pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x  (took %7lu usecs)\n", eax, ebx,
218 		(rc ? 0xffff : regs->eax & 0xffff), duration);
219 #endif
220 
221 	return rc;
222 }
223 
224 /*
225  * Call the System Management Mode BIOS.
226  */
227 static int i8k_smm(struct smm_regs *regs)
228 {
229 	int ret;
230 
231 	get_online_cpus();
232 	ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
233 	put_online_cpus();
234 
235 	return ret;
236 }
237 
238 /*
239  * Read the fan status.
240  */
241 static int i8k_get_fan_status(int fan)
242 {
243 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
244 
245 	if (disallow_fan_support)
246 		return -EINVAL;
247 
248 	regs.ebx = fan & 0xff;
249 	return i8k_smm(&regs) ? : regs.eax & 0xff;
250 }
251 
252 /*
253  * Read the fan speed in RPM.
254  */
255 static int i8k_get_fan_speed(int fan)
256 {
257 	struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
258 
259 	if (disallow_fan_support)
260 		return -EINVAL;
261 
262 	regs.ebx = fan & 0xff;
263 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
264 }
265 
266 /*
267  * Read the fan type.
268  */
269 static int _i8k_get_fan_type(int fan)
270 {
271 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
272 
273 	if (disallow_fan_support || disallow_fan_type_call)
274 		return -EINVAL;
275 
276 	regs.ebx = fan & 0xff;
277 	return i8k_smm(&regs) ? : regs.eax & 0xff;
278 }
279 
280 static int i8k_get_fan_type(int fan)
281 {
282 	/* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
283 	static int types[3] = { INT_MIN, INT_MIN, INT_MIN };
284 
285 	if (types[fan] == INT_MIN)
286 		types[fan] = _i8k_get_fan_type(fan);
287 
288 	return types[fan];
289 }
290 
291 /*
292  * Read the fan nominal rpm for specific fan speed.
293  */
294 static int i8k_get_fan_nominal_speed(int fan, int speed)
295 {
296 	struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
297 
298 	if (disallow_fan_support)
299 		return -EINVAL;
300 
301 	regs.ebx = (fan & 0xff) | (speed << 8);
302 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
303 }
304 
305 /*
306  * Enable or disable automatic BIOS fan control support
307  */
308 static int i8k_enable_fan_auto_mode(bool enable)
309 {
310 	struct smm_regs regs = { };
311 
312 	if (disallow_fan_support)
313 		return -EINVAL;
314 
315 	regs.eax = enable ? auto_fan : manual_fan;
316 	return i8k_smm(&regs);
317 }
318 
319 /*
320  * Set the fan speed (off, low, high). Returns the new fan status.
321  */
322 static int i8k_set_fan(int fan, int speed)
323 {
324 	struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
325 
326 	if (disallow_fan_support)
327 		return -EINVAL;
328 
329 	speed = (speed < 0) ? 0 : ((speed > i8k_fan_max) ? i8k_fan_max : speed);
330 	regs.ebx = (fan & 0xff) | (speed << 8);
331 
332 	return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
333 }
334 
335 static int i8k_get_temp_type(int sensor)
336 {
337 	struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
338 
339 	regs.ebx = sensor & 0xff;
340 	return i8k_smm(&regs) ? : regs.eax & 0xff;
341 }
342 
343 /*
344  * Read the cpu temperature.
345  */
346 static int _i8k_get_temp(int sensor)
347 {
348 	struct smm_regs regs = {
349 		.eax = I8K_SMM_GET_TEMP,
350 		.ebx = sensor & 0xff,
351 	};
352 
353 	return i8k_smm(&regs) ? : regs.eax & 0xff;
354 }
355 
356 static int i8k_get_temp(int sensor)
357 {
358 	int temp = _i8k_get_temp(sensor);
359 
360 	/*
361 	 * Sometimes the temperature sensor returns 0x99, which is out of range.
362 	 * In this case we retry (once) before returning an error.
363 	 # 1003655137 00000058 00005a4b
364 	 # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
365 	 # 1003655139 00000054 00005c52
366 	 */
367 	if (temp == 0x99) {
368 		msleep(100);
369 		temp = _i8k_get_temp(sensor);
370 	}
371 	/*
372 	 * Return -ENODATA for all invalid temperatures.
373 	 *
374 	 * Known instances are the 0x99 value as seen above as well as
375 	 * 0xc1 (193), which may be returned when trying to read the GPU
376 	 * temperature if the system supports a GPU and it is currently
377 	 * turned off.
378 	 */
379 	if (temp > I8K_MAX_TEMP)
380 		return -ENODATA;
381 
382 	return temp;
383 }
384 
385 static int i8k_get_dell_signature(int req_fn)
386 {
387 	struct smm_regs regs = { .eax = req_fn, };
388 	int rc;
389 
390 	rc = i8k_smm(&regs);
391 	if (rc < 0)
392 		return rc;
393 
394 	return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
395 }
396 
397 #if IS_ENABLED(CONFIG_I8K)
398 
399 /*
400  * Read the Fn key status.
401  */
402 static int i8k_get_fn_status(void)
403 {
404 	struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
405 	int rc;
406 
407 	rc = i8k_smm(&regs);
408 	if (rc < 0)
409 		return rc;
410 
411 	switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
412 	case I8K_FN_UP:
413 		return I8K_VOL_UP;
414 	case I8K_FN_DOWN:
415 		return I8K_VOL_DOWN;
416 	case I8K_FN_MUTE:
417 		return I8K_VOL_MUTE;
418 	default:
419 		return 0;
420 	}
421 }
422 
423 /*
424  * Read the power status.
425  */
426 static int i8k_get_power_status(void)
427 {
428 	struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
429 	int rc;
430 
431 	rc = i8k_smm(&regs);
432 	if (rc < 0)
433 		return rc;
434 
435 	return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
436 }
437 
438 /*
439  * Procfs interface
440  */
441 
442 static int
443 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
444 {
445 	int val = 0;
446 	int speed;
447 	unsigned char buff[16];
448 	int __user *argp = (int __user *)arg;
449 
450 	if (!argp)
451 		return -EINVAL;
452 
453 	switch (cmd) {
454 	case I8K_BIOS_VERSION:
455 		if (!isdigit(bios_version[0]) || !isdigit(bios_version[1]) ||
456 		    !isdigit(bios_version[2]))
457 			return -EINVAL;
458 
459 		val = (bios_version[0] << 16) |
460 				(bios_version[1] << 8) | bios_version[2];
461 		break;
462 
463 	case I8K_MACHINE_ID:
464 		if (restricted && !capable(CAP_SYS_ADMIN))
465 			return -EPERM;
466 
467 		memset(buff, 0, sizeof(buff));
468 		strlcpy(buff, bios_machineid, sizeof(buff));
469 		break;
470 
471 	case I8K_FN_STATUS:
472 		val = i8k_get_fn_status();
473 		break;
474 
475 	case I8K_POWER_STATUS:
476 		val = i8k_get_power_status();
477 		break;
478 
479 	case I8K_GET_TEMP:
480 		val = i8k_get_temp(0);
481 		break;
482 
483 	case I8K_GET_SPEED:
484 		if (copy_from_user(&val, argp, sizeof(int)))
485 			return -EFAULT;
486 
487 		val = i8k_get_fan_speed(val);
488 		break;
489 
490 	case I8K_GET_FAN:
491 		if (copy_from_user(&val, argp, sizeof(int)))
492 			return -EFAULT;
493 
494 		val = i8k_get_fan_status(val);
495 		break;
496 
497 	case I8K_SET_FAN:
498 		if (restricted && !capable(CAP_SYS_ADMIN))
499 			return -EPERM;
500 
501 		if (copy_from_user(&val, argp, sizeof(int)))
502 			return -EFAULT;
503 
504 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
505 			return -EFAULT;
506 
507 		val = i8k_set_fan(val, speed);
508 		break;
509 
510 	default:
511 		return -EINVAL;
512 	}
513 
514 	if (val < 0)
515 		return val;
516 
517 	switch (cmd) {
518 	case I8K_BIOS_VERSION:
519 		if (copy_to_user(argp, &val, 4))
520 			return -EFAULT;
521 
522 		break;
523 	case I8K_MACHINE_ID:
524 		if (copy_to_user(argp, buff, 16))
525 			return -EFAULT;
526 
527 		break;
528 	default:
529 		if (copy_to_user(argp, &val, sizeof(int)))
530 			return -EFAULT;
531 
532 		break;
533 	}
534 
535 	return 0;
536 }
537 
538 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
539 {
540 	long ret;
541 
542 	mutex_lock(&i8k_mutex);
543 	ret = i8k_ioctl_unlocked(fp, cmd, arg);
544 	mutex_unlock(&i8k_mutex);
545 
546 	return ret;
547 }
548 
549 /*
550  * Print the information for /proc/i8k.
551  */
552 static int i8k_proc_show(struct seq_file *seq, void *offset)
553 {
554 	int fn_key, cpu_temp, ac_power;
555 	int left_fan, right_fan, left_speed, right_speed;
556 
557 	cpu_temp	= i8k_get_temp(0);			/* 11100 µs */
558 	left_fan	= i8k_get_fan_status(I8K_FAN_LEFT);	/*   580 µs */
559 	right_fan	= i8k_get_fan_status(I8K_FAN_RIGHT);	/*   580 µs */
560 	left_speed	= i8k_get_fan_speed(I8K_FAN_LEFT);	/*   580 µs */
561 	right_speed	= i8k_get_fan_speed(I8K_FAN_RIGHT);	/*   580 µs */
562 	fn_key		= i8k_get_fn_status();			/*   750 µs */
563 	if (power_status)
564 		ac_power = i8k_get_power_status();		/* 14700 µs */
565 	else
566 		ac_power = -1;
567 
568 	/*
569 	 * Info:
570 	 *
571 	 * 1)  Format version (this will change if format changes)
572 	 * 2)  BIOS version
573 	 * 3)  BIOS machine ID
574 	 * 4)  Cpu temperature
575 	 * 5)  Left fan status
576 	 * 6)  Right fan status
577 	 * 7)  Left fan speed
578 	 * 8)  Right fan speed
579 	 * 9)  AC power
580 	 * 10) Fn Key status
581 	 */
582 	seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
583 		   I8K_PROC_FMT,
584 		   bios_version,
585 		   (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : bios_machineid,
586 		   cpu_temp,
587 		   left_fan, right_fan, left_speed, right_speed,
588 		   ac_power, fn_key);
589 
590 	return 0;
591 }
592 
593 static int i8k_open_fs(struct inode *inode, struct file *file)
594 {
595 	return single_open(file, i8k_proc_show, NULL);
596 }
597 
598 static const struct file_operations i8k_fops = {
599 	.owner		= THIS_MODULE,
600 	.open		= i8k_open_fs,
601 	.read		= seq_read,
602 	.llseek		= seq_lseek,
603 	.release	= single_release,
604 	.unlocked_ioctl	= i8k_ioctl,
605 };
606 
607 static void __init i8k_init_procfs(void)
608 {
609 	/* Register the proc entry */
610 	proc_create("i8k", 0, NULL, &i8k_fops);
611 }
612 
613 static void __exit i8k_exit_procfs(void)
614 {
615 	remove_proc_entry("i8k", NULL);
616 }
617 
618 #else
619 
620 static inline void __init i8k_init_procfs(void)
621 {
622 }
623 
624 static inline void __exit i8k_exit_procfs(void)
625 {
626 }
627 
628 #endif
629 
630 /*
631  * Hwmon interface
632  */
633 
634 static ssize_t i8k_hwmon_temp_label_show(struct device *dev,
635 					 struct device_attribute *devattr,
636 					 char *buf)
637 {
638 	static const char * const labels[] = {
639 		"CPU",
640 		"GPU",
641 		"SODIMM",
642 		"Other",
643 		"Ambient",
644 		"Other",
645 	};
646 	int index = to_sensor_dev_attr(devattr)->index;
647 	int type;
648 
649 	type = i8k_get_temp_type(index);
650 	if (type < 0)
651 		return type;
652 	if (type >= ARRAY_SIZE(labels))
653 		type = ARRAY_SIZE(labels) - 1;
654 	return sprintf(buf, "%s\n", labels[type]);
655 }
656 
657 static ssize_t i8k_hwmon_temp_show(struct device *dev,
658 				   struct device_attribute *devattr,
659 				   char *buf)
660 {
661 	int index = to_sensor_dev_attr(devattr)->index;
662 	int temp;
663 
664 	temp = i8k_get_temp(index);
665 	if (temp < 0)
666 		return temp;
667 	return sprintf(buf, "%d\n", temp * 1000);
668 }
669 
670 static ssize_t i8k_hwmon_fan_label_show(struct device *dev,
671 					struct device_attribute *devattr,
672 					char *buf)
673 {
674 	static const char * const labels[] = {
675 		"Processor Fan",
676 		"Motherboard Fan",
677 		"Video Fan",
678 		"Power Supply Fan",
679 		"Chipset Fan",
680 		"Other Fan",
681 	};
682 	int index = to_sensor_dev_attr(devattr)->index;
683 	bool dock = false;
684 	int type;
685 
686 	type = i8k_get_fan_type(index);
687 	if (type < 0)
688 		return type;
689 
690 	if (type & 0x10) {
691 		dock = true;
692 		type &= 0x0F;
693 	}
694 
695 	if (type >= ARRAY_SIZE(labels))
696 		type = (ARRAY_SIZE(labels) - 1);
697 
698 	return sprintf(buf, "%s%s\n", (dock ? "Docking " : ""), labels[type]);
699 }
700 
701 static ssize_t i8k_hwmon_fan_show(struct device *dev,
702 				  struct device_attribute *devattr, char *buf)
703 {
704 	int index = to_sensor_dev_attr(devattr)->index;
705 	int fan_speed;
706 
707 	fan_speed = i8k_get_fan_speed(index);
708 	if (fan_speed < 0)
709 		return fan_speed;
710 	return sprintf(buf, "%d\n", fan_speed);
711 }
712 
713 static ssize_t i8k_hwmon_pwm_show(struct device *dev,
714 				  struct device_attribute *devattr, char *buf)
715 {
716 	int index = to_sensor_dev_attr(devattr)->index;
717 	int status;
718 
719 	status = i8k_get_fan_status(index);
720 	if (status < 0)
721 		return -EIO;
722 	return sprintf(buf, "%d\n", clamp_val(status * i8k_pwm_mult, 0, 255));
723 }
724 
725 static ssize_t i8k_hwmon_pwm_store(struct device *dev,
726 				   struct device_attribute *attr,
727 				   const char *buf, size_t count)
728 {
729 	int index = to_sensor_dev_attr(attr)->index;
730 	unsigned long val;
731 	int err;
732 
733 	err = kstrtoul(buf, 10, &val);
734 	if (err)
735 		return err;
736 	val = clamp_val(DIV_ROUND_CLOSEST(val, i8k_pwm_mult), 0, i8k_fan_max);
737 
738 	mutex_lock(&i8k_mutex);
739 	err = i8k_set_fan(index, val);
740 	mutex_unlock(&i8k_mutex);
741 
742 	return err < 0 ? -EIO : count;
743 }
744 
745 static ssize_t i8k_hwmon_pwm_enable_store(struct device *dev,
746 					  struct device_attribute *attr,
747 					  const char *buf, size_t count)
748 {
749 	int err;
750 	bool enable;
751 	unsigned long val;
752 
753 	if (!auto_fan)
754 		return -ENODEV;
755 
756 	err = kstrtoul(buf, 10, &val);
757 	if (err)
758 		return err;
759 
760 	if (val == 1)
761 		enable = false;
762 	else if (val == 2)
763 		enable = true;
764 	else
765 		return -EINVAL;
766 
767 	mutex_lock(&i8k_mutex);
768 	err = i8k_enable_fan_auto_mode(enable);
769 	mutex_unlock(&i8k_mutex);
770 
771 	return err ? err : count;
772 }
773 
774 static SENSOR_DEVICE_ATTR_RO(temp1_input, i8k_hwmon_temp, 0);
775 static SENSOR_DEVICE_ATTR_RO(temp1_label, i8k_hwmon_temp_label, 0);
776 static SENSOR_DEVICE_ATTR_RO(temp2_input, i8k_hwmon_temp, 1);
777 static SENSOR_DEVICE_ATTR_RO(temp2_label, i8k_hwmon_temp_label, 1);
778 static SENSOR_DEVICE_ATTR_RO(temp3_input, i8k_hwmon_temp, 2);
779 static SENSOR_DEVICE_ATTR_RO(temp3_label, i8k_hwmon_temp_label, 2);
780 static SENSOR_DEVICE_ATTR_RO(temp4_input, i8k_hwmon_temp, 3);
781 static SENSOR_DEVICE_ATTR_RO(temp4_label, i8k_hwmon_temp_label, 3);
782 static SENSOR_DEVICE_ATTR_RO(temp5_input, i8k_hwmon_temp, 4);
783 static SENSOR_DEVICE_ATTR_RO(temp5_label, i8k_hwmon_temp_label, 4);
784 static SENSOR_DEVICE_ATTR_RO(temp6_input, i8k_hwmon_temp, 5);
785 static SENSOR_DEVICE_ATTR_RO(temp6_label, i8k_hwmon_temp_label, 5);
786 static SENSOR_DEVICE_ATTR_RO(temp7_input, i8k_hwmon_temp, 6);
787 static SENSOR_DEVICE_ATTR_RO(temp7_label, i8k_hwmon_temp_label, 6);
788 static SENSOR_DEVICE_ATTR_RO(temp8_input, i8k_hwmon_temp, 7);
789 static SENSOR_DEVICE_ATTR_RO(temp8_label, i8k_hwmon_temp_label, 7);
790 static SENSOR_DEVICE_ATTR_RO(temp9_input, i8k_hwmon_temp, 8);
791 static SENSOR_DEVICE_ATTR_RO(temp9_label, i8k_hwmon_temp_label, 8);
792 static SENSOR_DEVICE_ATTR_RO(temp10_input, i8k_hwmon_temp, 9);
793 static SENSOR_DEVICE_ATTR_RO(temp10_label, i8k_hwmon_temp_label, 9);
794 static SENSOR_DEVICE_ATTR_RO(fan1_input, i8k_hwmon_fan, 0);
795 static SENSOR_DEVICE_ATTR_RO(fan1_label, i8k_hwmon_fan_label, 0);
796 static SENSOR_DEVICE_ATTR_RW(pwm1, i8k_hwmon_pwm, 0);
797 static SENSOR_DEVICE_ATTR_WO(pwm1_enable, i8k_hwmon_pwm_enable, 0);
798 static SENSOR_DEVICE_ATTR_RO(fan2_input, i8k_hwmon_fan, 1);
799 static SENSOR_DEVICE_ATTR_RO(fan2_label, i8k_hwmon_fan_label, 1);
800 static SENSOR_DEVICE_ATTR_RW(pwm2, i8k_hwmon_pwm, 1);
801 static SENSOR_DEVICE_ATTR_RO(fan3_input, i8k_hwmon_fan, 2);
802 static SENSOR_DEVICE_ATTR_RO(fan3_label, i8k_hwmon_fan_label, 2);
803 static SENSOR_DEVICE_ATTR_RW(pwm3, i8k_hwmon_pwm, 2);
804 
805 static struct attribute *i8k_attrs[] = {
806 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
807 	&sensor_dev_attr_temp1_label.dev_attr.attr,	/* 1 */
808 	&sensor_dev_attr_temp2_input.dev_attr.attr,	/* 2 */
809 	&sensor_dev_attr_temp2_label.dev_attr.attr,	/* 3 */
810 	&sensor_dev_attr_temp3_input.dev_attr.attr,	/* 4 */
811 	&sensor_dev_attr_temp3_label.dev_attr.attr,	/* 5 */
812 	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 6 */
813 	&sensor_dev_attr_temp4_label.dev_attr.attr,	/* 7 */
814 	&sensor_dev_attr_temp5_input.dev_attr.attr,	/* 8 */
815 	&sensor_dev_attr_temp5_label.dev_attr.attr,	/* 9 */
816 	&sensor_dev_attr_temp6_input.dev_attr.attr,	/* 10 */
817 	&sensor_dev_attr_temp6_label.dev_attr.attr,	/* 11 */
818 	&sensor_dev_attr_temp7_input.dev_attr.attr,	/* 12 */
819 	&sensor_dev_attr_temp7_label.dev_attr.attr,	/* 13 */
820 	&sensor_dev_attr_temp8_input.dev_attr.attr,	/* 14 */
821 	&sensor_dev_attr_temp8_label.dev_attr.attr,	/* 15 */
822 	&sensor_dev_attr_temp9_input.dev_attr.attr,	/* 16 */
823 	&sensor_dev_attr_temp9_label.dev_attr.attr,	/* 17 */
824 	&sensor_dev_attr_temp10_input.dev_attr.attr,	/* 18 */
825 	&sensor_dev_attr_temp10_label.dev_attr.attr,	/* 19 */
826 	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 20 */
827 	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 21 */
828 	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 22 */
829 	&sensor_dev_attr_pwm1_enable.dev_attr.attr,	/* 23 */
830 	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 24 */
831 	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 25 */
832 	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 26 */
833 	&sensor_dev_attr_fan3_input.dev_attr.attr,	/* 27 */
834 	&sensor_dev_attr_fan3_label.dev_attr.attr,	/* 28 */
835 	&sensor_dev_attr_pwm3.dev_attr.attr,		/* 29 */
836 	NULL
837 };
838 
839 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
840 			      int index)
841 {
842 	if (disallow_fan_support && index >= 8)
843 		return 0;
844 	if (disallow_fan_type_call &&
845 	    (index == 9 || index == 12 || index == 15))
846 		return 0;
847 	if (index >= 0 && index <= 1 &&
848 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
849 		return 0;
850 	if (index >= 2 && index <= 3 &&
851 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
852 		return 0;
853 	if (index >= 4 && index <= 5 &&
854 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
855 		return 0;
856 	if (index >= 6 && index <= 7 &&
857 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
858 		return 0;
859 	if (index >= 8 && index <= 9 &&
860 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP5))
861 		return 0;
862 	if (index >= 10 && index <= 11 &&
863 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP6))
864 		return 0;
865 	if (index >= 12 && index <= 13 &&
866 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP7))
867 		return 0;
868 	if (index >= 14 && index <= 15 &&
869 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP8))
870 		return 0;
871 	if (index >= 16 && index <= 17 &&
872 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP9))
873 		return 0;
874 	if (index >= 18 && index <= 19 &&
875 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP10))
876 		return 0;
877 
878 	if (index >= 20 && index <= 23 &&
879 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
880 		return 0;
881 	if (index >= 24 && index <= 26 &&
882 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
883 		return 0;
884 	if (index >= 27 && index <= 29 &&
885 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN3))
886 		return 0;
887 
888 	if (index == 23 && !auto_fan)
889 		return 0;
890 
891 	return attr->mode;
892 }
893 
894 static const struct attribute_group i8k_group = {
895 	.attrs = i8k_attrs,
896 	.is_visible = i8k_is_visible,
897 };
898 __ATTRIBUTE_GROUPS(i8k);
899 
900 static int __init i8k_init_hwmon(void)
901 {
902 	int err;
903 
904 	i8k_hwmon_flags = 0;
905 
906 	/* CPU temperature attributes, if temperature type is OK */
907 	err = i8k_get_temp_type(0);
908 	if (err >= 0)
909 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;
910 	/* check for additional temperature sensors */
911 	err = i8k_get_temp_type(1);
912 	if (err >= 0)
913 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2;
914 	err = i8k_get_temp_type(2);
915 	if (err >= 0)
916 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3;
917 	err = i8k_get_temp_type(3);
918 	if (err >= 0)
919 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
920 	err = i8k_get_temp_type(4);
921 	if (err >= 0)
922 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP5;
923 	err = i8k_get_temp_type(5);
924 	if (err >= 0)
925 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP6;
926 	err = i8k_get_temp_type(6);
927 	if (err >= 0)
928 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP7;
929 	err = i8k_get_temp_type(7);
930 	if (err >= 0)
931 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP8;
932 	err = i8k_get_temp_type(8);
933 	if (err >= 0)
934 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP9;
935 	err = i8k_get_temp_type(9);
936 	if (err >= 0)
937 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP10;
938 
939 	/* First fan attributes, if fan status or type is OK */
940 	err = i8k_get_fan_status(0);
941 	if (err < 0)
942 		err = i8k_get_fan_type(0);
943 	if (err >= 0)
944 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
945 
946 	/* Second fan attributes, if fan status or type is OK */
947 	err = i8k_get_fan_status(1);
948 	if (err < 0)
949 		err = i8k_get_fan_type(1);
950 	if (err >= 0)
951 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;
952 
953 	/* Third fan attributes, if fan status or type is OK */
954 	err = i8k_get_fan_status(2);
955 	if (err < 0)
956 		err = i8k_get_fan_type(2);
957 	if (err >= 0)
958 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN3;
959 
960 	i8k_hwmon_dev = hwmon_device_register_with_groups(NULL, "dell_smm",
961 							  NULL, i8k_groups);
962 	if (IS_ERR(i8k_hwmon_dev)) {
963 		err = PTR_ERR(i8k_hwmon_dev);
964 		i8k_hwmon_dev = NULL;
965 		pr_err("hwmon registration failed (%d)\n", err);
966 		return err;
967 	}
968 	return 0;
969 }
970 
971 struct i8k_config_data {
972 	uint fan_mult;
973 	uint fan_max;
974 };
975 
976 enum i8k_configs {
977 	DELL_LATITUDE_D520,
978 	DELL_PRECISION_490,
979 	DELL_STUDIO,
980 	DELL_XPS,
981 };
982 
983 static const struct i8k_config_data i8k_config_data[] = {
984 	[DELL_LATITUDE_D520] = {
985 		.fan_mult = 1,
986 		.fan_max = I8K_FAN_TURBO,
987 	},
988 	[DELL_PRECISION_490] = {
989 		.fan_mult = 1,
990 		.fan_max = I8K_FAN_TURBO,
991 	},
992 	[DELL_STUDIO] = {
993 		.fan_mult = 1,
994 		.fan_max = I8K_FAN_HIGH,
995 	},
996 	[DELL_XPS] = {
997 		.fan_mult = 1,
998 		.fan_max = I8K_FAN_HIGH,
999 	},
1000 };
1001 
1002 static const struct dmi_system_id i8k_dmi_table[] __initconst = {
1003 	{
1004 		.ident = "Dell Inspiron",
1005 		.matches = {
1006 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
1007 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
1008 		},
1009 	},
1010 	{
1011 		.ident = "Dell Latitude",
1012 		.matches = {
1013 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
1014 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1015 		},
1016 	},
1017 	{
1018 		.ident = "Dell Inspiron 2",
1019 		.matches = {
1020 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1021 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
1022 		},
1023 	},
1024 	{
1025 		.ident = "Dell Latitude D520",
1026 		.matches = {
1027 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1028 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
1029 		},
1030 		.driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
1031 	},
1032 	{
1033 		.ident = "Dell Latitude 2",
1034 		.matches = {
1035 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1036 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1037 		},
1038 	},
1039 	{	/* UK Inspiron 6400  */
1040 		.ident = "Dell Inspiron 3",
1041 		.matches = {
1042 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1043 			DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
1044 		},
1045 	},
1046 	{
1047 		.ident = "Dell Inspiron 3",
1048 		.matches = {
1049 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1050 			DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
1051 		},
1052 	},
1053 	{
1054 		.ident = "Dell Precision 490",
1055 		.matches = {
1056 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1057 			DMI_MATCH(DMI_PRODUCT_NAME,
1058 				  "Precision WorkStation 490"),
1059 		},
1060 		.driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
1061 	},
1062 	{
1063 		.ident = "Dell Precision",
1064 		.matches = {
1065 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1066 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
1067 		},
1068 	},
1069 	{
1070 		.ident = "Dell Vostro",
1071 		.matches = {
1072 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1073 			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
1074 		},
1075 	},
1076 	{
1077 		.ident = "Dell XPS421",
1078 		.matches = {
1079 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1080 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
1081 		},
1082 	},
1083 	{
1084 		.ident = "Dell Studio",
1085 		.matches = {
1086 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1087 			DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
1088 		},
1089 		.driver_data = (void *)&i8k_config_data[DELL_STUDIO],
1090 	},
1091 	{
1092 		.ident = "Dell XPS 13",
1093 		.matches = {
1094 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1095 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13"),
1096 		},
1097 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
1098 	},
1099 	{
1100 		.ident = "Dell XPS M140",
1101 		.matches = {
1102 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1103 			DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
1104 		},
1105 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
1106 	},
1107 	{
1108 		.ident = "Dell XPS 15 9560",
1109 		.matches = {
1110 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1111 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS 15 9560"),
1112 		},
1113 	},
1114 	{
1115 		.ident = "Dell XPS 15 9570",
1116 		.matches = {
1117 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1118 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS 15 9570"),
1119 		},
1120 	},
1121 	{ }
1122 };
1123 
1124 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
1125 
1126 /*
1127  * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
1128  * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
1129  * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
1130  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
1131  */
1132 static const struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initconst = {
1133 	{
1134 		.ident = "Dell Studio XPS 8000",
1135 		.matches = {
1136 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1137 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
1138 		},
1139 	},
1140 	{
1141 		.ident = "Dell Studio XPS 8100",
1142 		.matches = {
1143 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1144 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
1145 		},
1146 	},
1147 	{
1148 		.ident = "Dell Inspiron 580",
1149 		.matches = {
1150 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1151 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
1152 		},
1153 	},
1154 	{ }
1155 };
1156 
1157 /*
1158  * On some machines all fan related SMM functions implemented by Dell BIOS
1159  * firmware freeze kernel for about 500ms. Until Dell fixes these problems fan
1160  * support for affected blacklisted Dell machines stay disabled.
1161  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=195751
1162  */
1163 static struct dmi_system_id i8k_blacklist_fan_support_dmi_table[] __initdata = {
1164 	{
1165 		.ident = "Dell Inspiron 7720",
1166 		.matches = {
1167 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1168 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
1169 		},
1170 	},
1171 	{
1172 		.ident = "Dell Vostro 3360",
1173 		.matches = {
1174 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1175 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
1176 		},
1177 	},
1178 	{
1179 		.ident = "Dell XPS13 9333",
1180 		.matches = {
1181 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1182 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
1183 		},
1184 	},
1185 	{ }
1186 };
1187 
1188 struct i8k_fan_control_data {
1189 	unsigned int manual_fan;
1190 	unsigned int auto_fan;
1191 };
1192 
1193 enum i8k_fan_controls {
1194 	I8K_FAN_34A3_35A3,
1195 };
1196 
1197 static const struct i8k_fan_control_data i8k_fan_control_data[] = {
1198 	[I8K_FAN_34A3_35A3] = {
1199 		.manual_fan = 0x34a3,
1200 		.auto_fan = 0x35a3,
1201 	},
1202 };
1203 
1204 static struct dmi_system_id i8k_whitelist_fan_control[] __initdata = {
1205 	{
1206 		.ident = "Dell Precision 5530",
1207 		.matches = {
1208 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1209 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
1210 		},
1211 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1212 	},
1213 	{
1214 		.ident = "Dell Latitude E6440",
1215 		.matches = {
1216 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1217 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
1218 		},
1219 		.driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1220 	},
1221 	{ }
1222 };
1223 
1224 /*
1225  * Probe for the presence of a supported laptop.
1226  */
1227 static int __init i8k_probe(void)
1228 {
1229 	const struct dmi_system_id *id, *fan_control;
1230 	int fan, ret;
1231 
1232 	/*
1233 	 * Get DMI information
1234 	 */
1235 	if (!dmi_check_system(i8k_dmi_table)) {
1236 		if (!ignore_dmi && !force)
1237 			return -ENODEV;
1238 
1239 		pr_info("not running on a supported Dell system.\n");
1240 		pr_info("vendor=%s, model=%s, version=%s\n",
1241 			i8k_get_dmi_data(DMI_SYS_VENDOR),
1242 			i8k_get_dmi_data(DMI_PRODUCT_NAME),
1243 			i8k_get_dmi_data(DMI_BIOS_VERSION));
1244 	}
1245 
1246 	if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
1247 		pr_warn("broken Dell BIOS detected, disallow fan support\n");
1248 		if (!force)
1249 			disallow_fan_support = true;
1250 	}
1251 
1252 	if (dmi_check_system(i8k_blacklist_fan_type_dmi_table)) {
1253 		pr_warn("broken Dell BIOS detected, disallow fan type call\n");
1254 		if (!force)
1255 			disallow_fan_type_call = true;
1256 	}
1257 
1258 	strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
1259 		sizeof(bios_version));
1260 	strlcpy(bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
1261 		sizeof(bios_machineid));
1262 
1263 	/*
1264 	 * Get SMM Dell signature
1265 	 */
1266 	if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
1267 	    i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
1268 		pr_err("unable to get SMM Dell signature\n");
1269 		if (!force)
1270 			return -ENODEV;
1271 	}
1272 
1273 	/*
1274 	 * Set fan multiplier and maximal fan speed from dmi config
1275 	 * Values specified in module parameters override values from dmi
1276 	 */
1277 	id = dmi_first_match(i8k_dmi_table);
1278 	if (id && id->driver_data) {
1279 		const struct i8k_config_data *conf = id->driver_data;
1280 		if (!fan_mult && conf->fan_mult)
1281 			fan_mult = conf->fan_mult;
1282 		if (!fan_max && conf->fan_max)
1283 			fan_max = conf->fan_max;
1284 	}
1285 
1286 	i8k_fan_max = fan_max ? : I8K_FAN_HIGH;	/* Must not be 0 */
1287 	i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
1288 
1289 	fan_control = dmi_first_match(i8k_whitelist_fan_control);
1290 	if (fan_control && fan_control->driver_data) {
1291 		const struct i8k_fan_control_data *data = fan_control->driver_data;
1292 
1293 		manual_fan = data->manual_fan;
1294 		auto_fan = data->auto_fan;
1295 		pr_info("enabling support for setting automatic/manual fan control\n");
1296 	}
1297 
1298 	if (!fan_mult) {
1299 		/*
1300 		 * Autodetect fan multiplier based on nominal rpm
1301 		 * If fan reports rpm value too high then set multiplier to 1
1302 		 */
1303 		for (fan = 0; fan < 2; ++fan) {
1304 			ret = i8k_get_fan_nominal_speed(fan, i8k_fan_max);
1305 			if (ret < 0)
1306 				continue;
1307 			if (ret > I8K_FAN_MAX_RPM)
1308 				i8k_fan_mult = 1;
1309 			break;
1310 		}
1311 	} else {
1312 		/* Fan multiplier was specified in module param or in dmi */
1313 		i8k_fan_mult = fan_mult;
1314 	}
1315 
1316 	return 0;
1317 }
1318 
1319 static int __init i8k_init(void)
1320 {
1321 	int err;
1322 
1323 	/* Are we running on an supported laptop? */
1324 	if (i8k_probe())
1325 		return -ENODEV;
1326 
1327 	err = i8k_init_hwmon();
1328 	if (err)
1329 		return err;
1330 
1331 	i8k_init_procfs();
1332 	return 0;
1333 }
1334 
1335 static void __exit i8k_exit(void)
1336 {
1337 	hwmon_device_unregister(i8k_hwmon_dev);
1338 	i8k_exit_procfs();
1339 }
1340 
1341 module_init(i8k_init);
1342 module_exit(i8k_exit);
1343