1 /*
2  * dell-smm-hwmon.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
3  *
4  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
5  *
6  * Hwmon integration:
7  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
8  * Copyright (C) 2013, 2014  Guenter Roeck <linux@roeck-us.net>
9  * Copyright (C) 2014, 2015  Pali Rohár <pali.rohar@gmail.com>
10  *
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License as published by the
13  * Free Software Foundation; either version 2, or (at your option) any
14  * later version.
15  *
16  * This program is distributed in the hope that it will be useful, but
17  * WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  * General Public License for more details.
20  */
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/delay.h>
25 #include <linux/module.h>
26 #include <linux/types.h>
27 #include <linux/init.h>
28 #include <linux/proc_fs.h>
29 #include <linux/seq_file.h>
30 #include <linux/dmi.h>
31 #include <linux/capability.h>
32 #include <linux/mutex.h>
33 #include <linux/hwmon.h>
34 #include <linux/hwmon-sysfs.h>
35 #include <linux/uaccess.h>
36 #include <linux/io.h>
37 #include <linux/sched.h>
38 
39 #include <linux/i8k.h>
40 
41 #define I8K_SMM_FN_STATUS	0x0025
42 #define I8K_SMM_POWER_STATUS	0x0069
43 #define I8K_SMM_SET_FAN		0x01a3
44 #define I8K_SMM_GET_FAN		0x00a3
45 #define I8K_SMM_GET_SPEED	0x02a3
46 #define I8K_SMM_GET_FAN_TYPE	0x03a3
47 #define I8K_SMM_GET_NOM_SPEED	0x04a3
48 #define I8K_SMM_GET_TEMP	0x10a3
49 #define I8K_SMM_GET_TEMP_TYPE	0x11a3
50 #define I8K_SMM_GET_DELL_SIG1	0xfea3
51 #define I8K_SMM_GET_DELL_SIG2	0xffa3
52 
53 #define I8K_FAN_MULT		30
54 #define I8K_FAN_MAX_RPM		30000
55 #define I8K_MAX_TEMP		127
56 
57 #define I8K_FN_NONE		0x00
58 #define I8K_FN_UP		0x01
59 #define I8K_FN_DOWN		0x02
60 #define I8K_FN_MUTE		0x04
61 #define I8K_FN_MASK		0x07
62 #define I8K_FN_SHIFT		8
63 
64 #define I8K_POWER_AC		0x05
65 #define I8K_POWER_BATTERY	0x01
66 
67 static DEFINE_MUTEX(i8k_mutex);
68 static char bios_version[4];
69 static struct device *i8k_hwmon_dev;
70 static u32 i8k_hwmon_flags;
71 static uint i8k_fan_mult = I8K_FAN_MULT;
72 static uint i8k_pwm_mult;
73 static uint i8k_fan_max = I8K_FAN_HIGH;
74 
75 #define I8K_HWMON_HAVE_TEMP1	(1 << 0)
76 #define I8K_HWMON_HAVE_TEMP2	(1 << 1)
77 #define I8K_HWMON_HAVE_TEMP3	(1 << 2)
78 #define I8K_HWMON_HAVE_TEMP4	(1 << 3)
79 #define I8K_HWMON_HAVE_FAN1	(1 << 4)
80 #define I8K_HWMON_HAVE_FAN2	(1 << 5)
81 
82 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
83 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
84 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
85 MODULE_LICENSE("GPL");
86 MODULE_ALIAS("i8k");
87 
88 static bool force;
89 module_param(force, bool, 0);
90 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
91 
92 static bool ignore_dmi;
93 module_param(ignore_dmi, bool, 0);
94 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
95 
96 #if IS_ENABLED(CONFIG_I8K)
97 static bool restricted;
98 module_param(restricted, bool, 0);
99 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
100 
101 static bool power_status;
102 module_param(power_status, bool, 0600);
103 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
104 #endif
105 
106 static uint fan_mult;
107 module_param(fan_mult, uint, 0);
108 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
109 
110 static uint fan_max;
111 module_param(fan_max, uint, 0);
112 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
113 
114 struct smm_regs {
115 	unsigned int eax;
116 	unsigned int ebx __packed;
117 	unsigned int ecx __packed;
118 	unsigned int edx __packed;
119 	unsigned int esi __packed;
120 	unsigned int edi __packed;
121 };
122 
123 static inline const char *i8k_get_dmi_data(int field)
124 {
125 	const char *dmi_data = dmi_get_system_info(field);
126 
127 	return dmi_data && *dmi_data ? dmi_data : "?";
128 }
129 
130 /*
131  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
132  */
133 static int i8k_smm(struct smm_regs *regs)
134 {
135 	int rc;
136 	int eax = regs->eax;
137 	cpumask_var_t old_mask;
138 
139 	/* SMM requires CPU 0 */
140 	if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
141 		return -ENOMEM;
142 	cpumask_copy(old_mask, &current->cpus_allowed);
143 	rc = set_cpus_allowed_ptr(current, cpumask_of(0));
144 	if (rc)
145 		goto out;
146 	if (smp_processor_id() != 0) {
147 		rc = -EBUSY;
148 		goto out;
149 	}
150 
151 #if defined(CONFIG_X86_64)
152 	asm volatile("pushq %%rax\n\t"
153 		"movl 0(%%rax),%%edx\n\t"
154 		"pushq %%rdx\n\t"
155 		"movl 4(%%rax),%%ebx\n\t"
156 		"movl 8(%%rax),%%ecx\n\t"
157 		"movl 12(%%rax),%%edx\n\t"
158 		"movl 16(%%rax),%%esi\n\t"
159 		"movl 20(%%rax),%%edi\n\t"
160 		"popq %%rax\n\t"
161 		"out %%al,$0xb2\n\t"
162 		"out %%al,$0x84\n\t"
163 		"xchgq %%rax,(%%rsp)\n\t"
164 		"movl %%ebx,4(%%rax)\n\t"
165 		"movl %%ecx,8(%%rax)\n\t"
166 		"movl %%edx,12(%%rax)\n\t"
167 		"movl %%esi,16(%%rax)\n\t"
168 		"movl %%edi,20(%%rax)\n\t"
169 		"popq %%rdx\n\t"
170 		"movl %%edx,0(%%rax)\n\t"
171 		"pushfq\n\t"
172 		"popq %%rax\n\t"
173 		"andl $1,%%eax\n"
174 		: "=a"(rc)
175 		:    "a"(regs)
176 		:    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
177 #else
178 	asm volatile("pushl %%eax\n\t"
179 	    "movl 0(%%eax),%%edx\n\t"
180 	    "push %%edx\n\t"
181 	    "movl 4(%%eax),%%ebx\n\t"
182 	    "movl 8(%%eax),%%ecx\n\t"
183 	    "movl 12(%%eax),%%edx\n\t"
184 	    "movl 16(%%eax),%%esi\n\t"
185 	    "movl 20(%%eax),%%edi\n\t"
186 	    "popl %%eax\n\t"
187 	    "out %%al,$0xb2\n\t"
188 	    "out %%al,$0x84\n\t"
189 	    "xchgl %%eax,(%%esp)\n\t"
190 	    "movl %%ebx,4(%%eax)\n\t"
191 	    "movl %%ecx,8(%%eax)\n\t"
192 	    "movl %%edx,12(%%eax)\n\t"
193 	    "movl %%esi,16(%%eax)\n\t"
194 	    "movl %%edi,20(%%eax)\n\t"
195 	    "popl %%edx\n\t"
196 	    "movl %%edx,0(%%eax)\n\t"
197 	    "lahf\n\t"
198 	    "shrl $8,%%eax\n\t"
199 	    "andl $1,%%eax\n"
200 	    : "=a"(rc)
201 	    :    "a"(regs)
202 	    :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
203 #endif
204 	if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
205 		rc = -EINVAL;
206 
207 out:
208 	set_cpus_allowed_ptr(current, old_mask);
209 	free_cpumask_var(old_mask);
210 	return rc;
211 }
212 
213 /*
214  * Read the fan status.
215  */
216 static int i8k_get_fan_status(int fan)
217 {
218 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
219 
220 	regs.ebx = fan & 0xff;
221 	return i8k_smm(&regs) ? : regs.eax & 0xff;
222 }
223 
224 /*
225  * Read the fan speed in RPM.
226  */
227 static int i8k_get_fan_speed(int fan)
228 {
229 	struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
230 
231 	regs.ebx = fan & 0xff;
232 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
233 }
234 
235 /*
236  * Read the fan type.
237  */
238 static int i8k_get_fan_type(int fan)
239 {
240 	struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
241 
242 	regs.ebx = fan & 0xff;
243 	return i8k_smm(&regs) ? : regs.eax & 0xff;
244 }
245 
246 /*
247  * Read the fan nominal rpm for specific fan speed.
248  */
249 static int i8k_get_fan_nominal_speed(int fan, int speed)
250 {
251 	struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
252 
253 	regs.ebx = (fan & 0xff) | (speed << 8);
254 	return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
255 }
256 
257 /*
258  * Set the fan speed (off, low, high). Returns the new fan status.
259  */
260 static int i8k_set_fan(int fan, int speed)
261 {
262 	struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
263 
264 	speed = (speed < 0) ? 0 : ((speed > i8k_fan_max) ? i8k_fan_max : speed);
265 	regs.ebx = (fan & 0xff) | (speed << 8);
266 
267 	return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
268 }
269 
270 static int i8k_get_temp_type(int sensor)
271 {
272 	struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
273 
274 	regs.ebx = sensor & 0xff;
275 	return i8k_smm(&regs) ? : regs.eax & 0xff;
276 }
277 
278 /*
279  * Read the cpu temperature.
280  */
281 static int _i8k_get_temp(int sensor)
282 {
283 	struct smm_regs regs = {
284 		.eax = I8K_SMM_GET_TEMP,
285 		.ebx = sensor & 0xff,
286 	};
287 
288 	return i8k_smm(&regs) ? : regs.eax & 0xff;
289 }
290 
291 static int i8k_get_temp(int sensor)
292 {
293 	int temp = _i8k_get_temp(sensor);
294 
295 	/*
296 	 * Sometimes the temperature sensor returns 0x99, which is out of range.
297 	 * In this case we retry (once) before returning an error.
298 	 # 1003655137 00000058 00005a4b
299 	 # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
300 	 # 1003655139 00000054 00005c52
301 	 */
302 	if (temp == 0x99) {
303 		msleep(100);
304 		temp = _i8k_get_temp(sensor);
305 	}
306 	/*
307 	 * Return -ENODATA for all invalid temperatures.
308 	 *
309 	 * Known instances are the 0x99 value as seen above as well as
310 	 * 0xc1 (193), which may be returned when trying to read the GPU
311 	 * temperature if the system supports a GPU and it is currently
312 	 * turned off.
313 	 */
314 	if (temp > I8K_MAX_TEMP)
315 		return -ENODATA;
316 
317 	return temp;
318 }
319 
320 static int i8k_get_dell_signature(int req_fn)
321 {
322 	struct smm_regs regs = { .eax = req_fn, };
323 	int rc;
324 
325 	rc = i8k_smm(&regs);
326 	if (rc < 0)
327 		return rc;
328 
329 	return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
330 }
331 
332 #if IS_ENABLED(CONFIG_I8K)
333 
334 /*
335  * Read the Fn key status.
336  */
337 static int i8k_get_fn_status(void)
338 {
339 	struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
340 	int rc;
341 
342 	rc = i8k_smm(&regs);
343 	if (rc < 0)
344 		return rc;
345 
346 	switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
347 	case I8K_FN_UP:
348 		return I8K_VOL_UP;
349 	case I8K_FN_DOWN:
350 		return I8K_VOL_DOWN;
351 	case I8K_FN_MUTE:
352 		return I8K_VOL_MUTE;
353 	default:
354 		return 0;
355 	}
356 }
357 
358 /*
359  * Read the power status.
360  */
361 static int i8k_get_power_status(void)
362 {
363 	struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
364 	int rc;
365 
366 	rc = i8k_smm(&regs);
367 	if (rc < 0)
368 		return rc;
369 
370 	return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
371 }
372 
373 /*
374  * Procfs interface
375  */
376 
377 static int
378 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
379 {
380 	int val = 0;
381 	int speed;
382 	unsigned char buff[16];
383 	int __user *argp = (int __user *)arg;
384 
385 	if (!argp)
386 		return -EINVAL;
387 
388 	switch (cmd) {
389 	case I8K_BIOS_VERSION:
390 		val = (bios_version[0] << 16) |
391 				(bios_version[1] << 8) | bios_version[2];
392 		break;
393 
394 	case I8K_MACHINE_ID:
395 		memset(buff, 0, 16);
396 		strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
397 			sizeof(buff));
398 		break;
399 
400 	case I8K_FN_STATUS:
401 		val = i8k_get_fn_status();
402 		break;
403 
404 	case I8K_POWER_STATUS:
405 		val = i8k_get_power_status();
406 		break;
407 
408 	case I8K_GET_TEMP:
409 		val = i8k_get_temp(0);
410 		break;
411 
412 	case I8K_GET_SPEED:
413 		if (copy_from_user(&val, argp, sizeof(int)))
414 			return -EFAULT;
415 
416 		val = i8k_get_fan_speed(val);
417 		break;
418 
419 	case I8K_GET_FAN:
420 		if (copy_from_user(&val, argp, sizeof(int)))
421 			return -EFAULT;
422 
423 		val = i8k_get_fan_status(val);
424 		break;
425 
426 	case I8K_SET_FAN:
427 		if (restricted && !capable(CAP_SYS_ADMIN))
428 			return -EPERM;
429 
430 		if (copy_from_user(&val, argp, sizeof(int)))
431 			return -EFAULT;
432 
433 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
434 			return -EFAULT;
435 
436 		val = i8k_set_fan(val, speed);
437 		break;
438 
439 	default:
440 		return -EINVAL;
441 	}
442 
443 	if (val < 0)
444 		return val;
445 
446 	switch (cmd) {
447 	case I8K_BIOS_VERSION:
448 		if (copy_to_user(argp, &val, 4))
449 			return -EFAULT;
450 
451 		break;
452 	case I8K_MACHINE_ID:
453 		if (copy_to_user(argp, buff, 16))
454 			return -EFAULT;
455 
456 		break;
457 	default:
458 		if (copy_to_user(argp, &val, sizeof(int)))
459 			return -EFAULT;
460 
461 		break;
462 	}
463 
464 	return 0;
465 }
466 
467 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
468 {
469 	long ret;
470 
471 	mutex_lock(&i8k_mutex);
472 	ret = i8k_ioctl_unlocked(fp, cmd, arg);
473 	mutex_unlock(&i8k_mutex);
474 
475 	return ret;
476 }
477 
478 /*
479  * Print the information for /proc/i8k.
480  */
481 static int i8k_proc_show(struct seq_file *seq, void *offset)
482 {
483 	int fn_key, cpu_temp, ac_power;
484 	int left_fan, right_fan, left_speed, right_speed;
485 
486 	cpu_temp	= i8k_get_temp(0);			/* 11100 µs */
487 	left_fan	= i8k_get_fan_status(I8K_FAN_LEFT);	/*   580 µs */
488 	right_fan	= i8k_get_fan_status(I8K_FAN_RIGHT);	/*   580 µs */
489 	left_speed	= i8k_get_fan_speed(I8K_FAN_LEFT);	/*   580 µs */
490 	right_speed	= i8k_get_fan_speed(I8K_FAN_RIGHT);	/*   580 µs */
491 	fn_key		= i8k_get_fn_status();			/*   750 µs */
492 	if (power_status)
493 		ac_power = i8k_get_power_status();		/* 14700 µs */
494 	else
495 		ac_power = -1;
496 
497 	/*
498 	 * Info:
499 	 *
500 	 * 1)  Format version (this will change if format changes)
501 	 * 2)  BIOS version
502 	 * 3)  BIOS machine ID
503 	 * 4)  Cpu temperature
504 	 * 5)  Left fan status
505 	 * 6)  Right fan status
506 	 * 7)  Left fan speed
507 	 * 8)  Right fan speed
508 	 * 9)  AC power
509 	 * 10) Fn Key status
510 	 */
511 	seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
512 		   I8K_PROC_FMT,
513 		   bios_version,
514 		   i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
515 		   cpu_temp,
516 		   left_fan, right_fan, left_speed, right_speed,
517 		   ac_power, fn_key);
518 
519 	return 0;
520 }
521 
522 static int i8k_open_fs(struct inode *inode, struct file *file)
523 {
524 	return single_open(file, i8k_proc_show, NULL);
525 }
526 
527 static const struct file_operations i8k_fops = {
528 	.owner		= THIS_MODULE,
529 	.open		= i8k_open_fs,
530 	.read		= seq_read,
531 	.llseek		= seq_lseek,
532 	.release	= single_release,
533 	.unlocked_ioctl	= i8k_ioctl,
534 };
535 
536 static void __init i8k_init_procfs(void)
537 {
538 	/* Register the proc entry */
539 	proc_create("i8k", 0, NULL, &i8k_fops);
540 }
541 
542 static void __exit i8k_exit_procfs(void)
543 {
544 	remove_proc_entry("i8k", NULL);
545 }
546 
547 #else
548 
549 static inline void __init i8k_init_procfs(void)
550 {
551 }
552 
553 static inline void __exit i8k_exit_procfs(void)
554 {
555 }
556 
557 #endif
558 
559 /*
560  * Hwmon interface
561  */
562 
563 static ssize_t i8k_hwmon_show_temp_label(struct device *dev,
564 					 struct device_attribute *devattr,
565 					 char *buf)
566 {
567 	static const char * const labels[] = {
568 		"CPU",
569 		"GPU",
570 		"SODIMM",
571 		"Other",
572 		"Ambient",
573 		"Other",
574 	};
575 	int index = to_sensor_dev_attr(devattr)->index;
576 	int type;
577 
578 	type = i8k_get_temp_type(index);
579 	if (type < 0)
580 		return type;
581 	if (type >= ARRAY_SIZE(labels))
582 		type = ARRAY_SIZE(labels) - 1;
583 	return sprintf(buf, "%s\n", labels[type]);
584 }
585 
586 static ssize_t i8k_hwmon_show_temp(struct device *dev,
587 				   struct device_attribute *devattr,
588 				   char *buf)
589 {
590 	int index = to_sensor_dev_attr(devattr)->index;
591 	int temp;
592 
593 	temp = i8k_get_temp(index);
594 	if (temp < 0)
595 		return temp;
596 	return sprintf(buf, "%d\n", temp * 1000);
597 }
598 
599 static ssize_t i8k_hwmon_show_fan_label(struct device *dev,
600 					struct device_attribute *devattr,
601 					char *buf)
602 {
603 	static const char * const labels[] = {
604 		"Processor Fan",
605 		"Motherboard Fan",
606 		"Video Fan",
607 		"Power Supply Fan",
608 		"Chipset Fan",
609 		"Other Fan",
610 	};
611 	int index = to_sensor_dev_attr(devattr)->index;
612 	bool dock = false;
613 	int type;
614 
615 	type = i8k_get_fan_type(index);
616 	if (type < 0)
617 		return type;
618 
619 	if (type & 0x10) {
620 		dock = true;
621 		type &= 0x0F;
622 	}
623 
624 	if (type >= ARRAY_SIZE(labels))
625 		type = (ARRAY_SIZE(labels) - 1);
626 
627 	return sprintf(buf, "%s%s\n", (dock ? "Docking " : ""), labels[type]);
628 }
629 
630 static ssize_t i8k_hwmon_show_fan(struct device *dev,
631 				  struct device_attribute *devattr,
632 				  char *buf)
633 {
634 	int index = to_sensor_dev_attr(devattr)->index;
635 	int fan_speed;
636 
637 	fan_speed = i8k_get_fan_speed(index);
638 	if (fan_speed < 0)
639 		return fan_speed;
640 	return sprintf(buf, "%d\n", fan_speed);
641 }
642 
643 static ssize_t i8k_hwmon_show_pwm(struct device *dev,
644 				  struct device_attribute *devattr,
645 				  char *buf)
646 {
647 	int index = to_sensor_dev_attr(devattr)->index;
648 	int status;
649 
650 	status = i8k_get_fan_status(index);
651 	if (status < 0)
652 		return -EIO;
653 	return sprintf(buf, "%d\n", clamp_val(status * i8k_pwm_mult, 0, 255));
654 }
655 
656 static ssize_t i8k_hwmon_set_pwm(struct device *dev,
657 				 struct device_attribute *attr,
658 				 const char *buf, size_t count)
659 {
660 	int index = to_sensor_dev_attr(attr)->index;
661 	unsigned long val;
662 	int err;
663 
664 	err = kstrtoul(buf, 10, &val);
665 	if (err)
666 		return err;
667 	val = clamp_val(DIV_ROUND_CLOSEST(val, i8k_pwm_mult), 0, i8k_fan_max);
668 
669 	mutex_lock(&i8k_mutex);
670 	err = i8k_set_fan(index, val);
671 	mutex_unlock(&i8k_mutex);
672 
673 	return err < 0 ? -EIO : count;
674 }
675 
676 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 0);
677 static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
678 			  0);
679 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 1);
680 static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
681 			  1);
682 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
683 static SENSOR_DEVICE_ATTR(temp3_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
684 			  2);
685 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
686 static SENSOR_DEVICE_ATTR(temp4_label, S_IRUGO, i8k_hwmon_show_temp_label, NULL,
687 			  3);
688 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL, 0);
689 static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
690 			  0);
691 static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
692 			  i8k_hwmon_set_pwm, 0);
693 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
694 			  1);
695 static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_fan_label, NULL,
696 			  1);
697 static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
698 			  i8k_hwmon_set_pwm, 1);
699 
700 static struct attribute *i8k_attrs[] = {
701 	&sensor_dev_attr_temp1_input.dev_attr.attr,	/* 0 */
702 	&sensor_dev_attr_temp1_label.dev_attr.attr,	/* 1 */
703 	&sensor_dev_attr_temp2_input.dev_attr.attr,	/* 2 */
704 	&sensor_dev_attr_temp2_label.dev_attr.attr,	/* 3 */
705 	&sensor_dev_attr_temp3_input.dev_attr.attr,	/* 4 */
706 	&sensor_dev_attr_temp3_label.dev_attr.attr,	/* 5 */
707 	&sensor_dev_attr_temp4_input.dev_attr.attr,	/* 6 */
708 	&sensor_dev_attr_temp4_label.dev_attr.attr,	/* 7 */
709 	&sensor_dev_attr_fan1_input.dev_attr.attr,	/* 8 */
710 	&sensor_dev_attr_fan1_label.dev_attr.attr,	/* 9 */
711 	&sensor_dev_attr_pwm1.dev_attr.attr,		/* 10 */
712 	&sensor_dev_attr_fan2_input.dev_attr.attr,	/* 11 */
713 	&sensor_dev_attr_fan2_label.dev_attr.attr,	/* 12 */
714 	&sensor_dev_attr_pwm2.dev_attr.attr,		/* 13 */
715 	NULL
716 };
717 
718 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
719 			      int index)
720 {
721 	if (index >= 0 && index <= 1 &&
722 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
723 		return 0;
724 	if (index >= 2 && index <= 3 &&
725 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
726 		return 0;
727 	if (index >= 4 && index <= 5 &&
728 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
729 		return 0;
730 	if (index >= 6 && index <= 7 &&
731 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
732 		return 0;
733 	if (index >= 8 && index <= 10 &&
734 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
735 		return 0;
736 	if (index >= 11 && index <= 13 &&
737 	    !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
738 		return 0;
739 
740 	return attr->mode;
741 }
742 
743 static const struct attribute_group i8k_group = {
744 	.attrs = i8k_attrs,
745 	.is_visible = i8k_is_visible,
746 };
747 __ATTRIBUTE_GROUPS(i8k);
748 
749 static int __init i8k_init_hwmon(void)
750 {
751 	int err;
752 
753 	i8k_hwmon_flags = 0;
754 
755 	/* CPU temperature attributes, if temperature type is OK */
756 	err = i8k_get_temp_type(0);
757 	if (err >= 0)
758 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;
759 	/* check for additional temperature sensors */
760 	err = i8k_get_temp_type(1);
761 	if (err >= 0)
762 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2;
763 	err = i8k_get_temp_type(2);
764 	if (err >= 0)
765 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3;
766 	err = i8k_get_temp_type(3);
767 	if (err >= 0)
768 		i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
769 
770 	/* First fan attributes, if fan type is OK */
771 	err = i8k_get_fan_type(0);
772 	if (err >= 0)
773 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
774 
775 	/* Second fan attributes, if fan type is OK */
776 	err = i8k_get_fan_type(1);
777 	if (err >= 0)
778 		i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;
779 
780 	i8k_hwmon_dev = hwmon_device_register_with_groups(NULL, "dell_smm",
781 							  NULL, i8k_groups);
782 	if (IS_ERR(i8k_hwmon_dev)) {
783 		err = PTR_ERR(i8k_hwmon_dev);
784 		i8k_hwmon_dev = NULL;
785 		pr_err("hwmon registration failed (%d)\n", err);
786 		return err;
787 	}
788 	return 0;
789 }
790 
791 struct i8k_config_data {
792 	uint fan_mult;
793 	uint fan_max;
794 };
795 
796 enum i8k_configs {
797 	DELL_LATITUDE_D520,
798 	DELL_PRECISION_490,
799 	DELL_STUDIO,
800 	DELL_XPS,
801 };
802 
803 static const struct i8k_config_data i8k_config_data[] = {
804 	[DELL_LATITUDE_D520] = {
805 		.fan_mult = 1,
806 		.fan_max = I8K_FAN_TURBO,
807 	},
808 	[DELL_PRECISION_490] = {
809 		.fan_mult = 1,
810 		.fan_max = I8K_FAN_TURBO,
811 	},
812 	[DELL_STUDIO] = {
813 		.fan_mult = 1,
814 		.fan_max = I8K_FAN_HIGH,
815 	},
816 	[DELL_XPS] = {
817 		.fan_mult = 1,
818 		.fan_max = I8K_FAN_HIGH,
819 	},
820 };
821 
822 static struct dmi_system_id i8k_dmi_table[] __initdata = {
823 	{
824 		.ident = "Dell Inspiron",
825 		.matches = {
826 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
827 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
828 		},
829 	},
830 	{
831 		.ident = "Dell Latitude",
832 		.matches = {
833 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
834 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
835 		},
836 	},
837 	{
838 		.ident = "Dell Inspiron 2",
839 		.matches = {
840 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
841 			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
842 		},
843 	},
844 	{
845 		.ident = "Dell Latitude D520",
846 		.matches = {
847 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
848 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
849 		},
850 		.driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
851 	},
852 	{
853 		.ident = "Dell Latitude 2",
854 		.matches = {
855 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
856 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
857 		},
858 	},
859 	{	/* UK Inspiron 6400  */
860 		.ident = "Dell Inspiron 3",
861 		.matches = {
862 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
863 			DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
864 		},
865 	},
866 	{
867 		.ident = "Dell Inspiron 3",
868 		.matches = {
869 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
870 			DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
871 		},
872 	},
873 	{
874 		.ident = "Dell Precision 490",
875 		.matches = {
876 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
877 			DMI_MATCH(DMI_PRODUCT_NAME,
878 				  "Precision WorkStation 490"),
879 		},
880 		.driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
881 	},
882 	{
883 		.ident = "Dell Precision",
884 		.matches = {
885 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
886 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
887 		},
888 	},
889 	{
890 		.ident = "Dell Vostro",
891 		.matches = {
892 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
893 			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
894 		},
895 	},
896 	{
897 		.ident = "Dell XPS421",
898 		.matches = {
899 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
900 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
901 		},
902 	},
903 	{
904 		.ident = "Dell Studio",
905 		.matches = {
906 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
907 			DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
908 		},
909 		.driver_data = (void *)&i8k_config_data[DELL_STUDIO],
910 	},
911 	{
912 		.ident = "Dell XPS 13",
913 		.matches = {
914 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
915 			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13"),
916 		},
917 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
918 	},
919 	{
920 		.ident = "Dell XPS M140",
921 		.matches = {
922 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
923 			DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
924 		},
925 		.driver_data = (void *)&i8k_config_data[DELL_XPS],
926 	},
927 	{ }
928 };
929 
930 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
931 
932 static struct dmi_system_id i8k_blacklist_dmi_table[] __initdata = {
933 	{
934 		/*
935 		 * CPU fan speed going up and down on Dell Studio XPS 8100
936 		 * for unknown reasons.
937 		 */
938 		.ident = "Dell Studio XPS 8100",
939 		.matches = {
940 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
941 			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
942 		},
943 	},
944 	{ }
945 };
946 
947 /*
948  * Probe for the presence of a supported laptop.
949  */
950 static int __init i8k_probe(void)
951 {
952 	const struct dmi_system_id *id;
953 	int fan, ret;
954 
955 	/*
956 	 * Get DMI information
957 	 */
958 	if (!dmi_check_system(i8k_dmi_table) ||
959 	    dmi_check_system(i8k_blacklist_dmi_table)) {
960 		if (!ignore_dmi && !force)
961 			return -ENODEV;
962 
963 		pr_info("not running on a supported Dell system.\n");
964 		pr_info("vendor=%s, model=%s, version=%s\n",
965 			i8k_get_dmi_data(DMI_SYS_VENDOR),
966 			i8k_get_dmi_data(DMI_PRODUCT_NAME),
967 			i8k_get_dmi_data(DMI_BIOS_VERSION));
968 	}
969 
970 	strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
971 		sizeof(bios_version));
972 
973 	/*
974 	 * Get SMM Dell signature
975 	 */
976 	if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
977 	    i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
978 		pr_err("unable to get SMM Dell signature\n");
979 		if (!force)
980 			return -ENODEV;
981 	}
982 
983 	/*
984 	 * Set fan multiplier and maximal fan speed from dmi config
985 	 * Values specified in module parameters override values from dmi
986 	 */
987 	id = dmi_first_match(i8k_dmi_table);
988 	if (id && id->driver_data) {
989 		const struct i8k_config_data *conf = id->driver_data;
990 		if (!fan_mult && conf->fan_mult)
991 			fan_mult = conf->fan_mult;
992 		if (!fan_max && conf->fan_max)
993 			fan_max = conf->fan_max;
994 	}
995 
996 	i8k_fan_max = fan_max ? : I8K_FAN_HIGH;	/* Must not be 0 */
997 	i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
998 
999 	if (!fan_mult) {
1000 		/*
1001 		 * Autodetect fan multiplier based on nominal rpm
1002 		 * If fan reports rpm value too high then set multiplier to 1
1003 		 */
1004 		for (fan = 0; fan < 2; ++fan) {
1005 			ret = i8k_get_fan_nominal_speed(fan, i8k_fan_max);
1006 			if (ret < 0)
1007 				continue;
1008 			if (ret > I8K_FAN_MAX_RPM)
1009 				i8k_fan_mult = 1;
1010 			break;
1011 		}
1012 	} else {
1013 		/* Fan multiplier was specified in module param or in dmi */
1014 		i8k_fan_mult = fan_mult;
1015 	}
1016 
1017 	return 0;
1018 }
1019 
1020 static int __init i8k_init(void)
1021 {
1022 	int err;
1023 
1024 	/* Are we running on an supported laptop? */
1025 	if (i8k_probe())
1026 		return -ENODEV;
1027 
1028 	err = i8k_init_hwmon();
1029 	if (err)
1030 		return err;
1031 
1032 	i8k_init_procfs();
1033 	return 0;
1034 }
1035 
1036 static void __exit i8k_exit(void)
1037 {
1038 	hwmon_device_unregister(i8k_hwmon_dev);
1039 	i8k_exit_procfs();
1040 }
1041 
1042 module_init(i8k_init);
1043 module_exit(i8k_exit);
1044