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@kernel.org>
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/capability.h>
16#include <linux/cpu.h>
17#include <linux/ctype.h>
18#include <linux/delay.h>
19#include <linux/dmi.h>
20#include <linux/err.h>
21#include <linux/errno.h>
22#include <linux/hwmon.h>
23#include <linux/init.h>
24#include <linux/kconfig.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/mutex.h>
28#include <linux/platform_device.h>
29#include <linux/proc_fs.h>
30#include <linux/seq_file.h>
31#include <linux/slab.h>
32#include <linux/smp.h>
33#include <linux/string.h>
34#include <linux/thermal.h>
35#include <linux/types.h>
36#include <linux/uaccess.h>
37
38#include <linux/i8k.h>
39
40#define I8K_SMM_FN_STATUS 0x0025
41#define I8K_SMM_POWER_STATUS 0x0069
42#define I8K_SMM_SET_FAN 0x01a3
43#define I8K_SMM_GET_FAN 0x00a3
44#define I8K_SMM_GET_SPEED 0x02a3
45#define I8K_SMM_GET_FAN_TYPE 0x03a3
46#define I8K_SMM_GET_NOM_SPEED 0x04a3
47#define I8K_SMM_GET_TEMP 0x10a3
48#define I8K_SMM_GET_TEMP_TYPE 0x11a3
49#define I8K_SMM_GET_DELL_SIG1 0xfea3
50#define I8K_SMM_GET_DELL_SIG2 0xffa3
51
52/* in usecs */
53#define DELL_SMM_MAX_DURATION 250000
54
55#define I8K_FAN_MULT 30
56#define I8K_FAN_RPM_THRESHOLD 1000
57#define I8K_MAX_TEMP 127
58
59#define I8K_FN_NONE 0x00
60#define I8K_FN_UP 0x01
61#define I8K_FN_DOWN 0x02
62#define I8K_FN_MUTE 0x04
63#define I8K_FN_MASK 0x07
64#define I8K_FN_SHIFT 8
65
66#define I8K_POWER_AC 0x05
67#define I8K_POWER_BATTERY 0x01
68
69#define DELL_SMM_NO_TEMP 10
70#define DELL_SMM_NO_FANS 3
71
72struct dell_smm_data {
73 struct mutex i8k_mutex; /* lock for sensors writes */
74 char bios_version[4];
75 char bios_machineid[16];
76 uint i8k_fan_mult;
77 uint i8k_pwm_mult;
78 uint i8k_fan_max;
79 bool disallow_fan_type_call;
80 bool disallow_fan_support;
81 unsigned int manual_fan;
82 unsigned int auto_fan;
83 int temp_type[DELL_SMM_NO_TEMP];
84 bool fan[DELL_SMM_NO_FANS];
85 int fan_type[DELL_SMM_NO_FANS];
86 int *fan_nominal_speed[DELL_SMM_NO_FANS];
87};
88
89struct dell_smm_cooling_data {
90 u8 fan_num;
91 struct dell_smm_data *data;
92};
93
94MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
95MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
96MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
97MODULE_LICENSE("GPL");
98MODULE_ALIAS("i8k");
99
100static bool force;
101module_param_unsafe(force, bool, 0);
102MODULE_PARM_DESC(force, "Force loading without checking for supported models and features");
103
104static bool ignore_dmi;
105module_param(ignore_dmi, bool, 0);
106MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
107
108#if IS_ENABLED(CONFIG_I8K)
109static bool restricted = true;
110module_param(restricted, bool, 0);
111MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");
112
113static bool power_status;
114module_param(power_status, bool, 0600);
115MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
116#endif
117
118static uint fan_mult;
119module_param(fan_mult, uint, 0);
120MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
121
122static uint fan_max;
123module_param(fan_max, uint, 0);
124MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
125
126struct smm_regs {
127 unsigned int eax;
128 unsigned int ebx;
129 unsigned int ecx;
130 unsigned int edx;
131 unsigned int esi;
132 unsigned int edi;
133};
134
135static const char * const temp_labels[] = {
136 "CPU",
137 "GPU",
138 "SODIMM",
139 "Other",
140 "Ambient",
141 "Other",
142};
143
144static const char * const fan_labels[] = {
145 "Processor Fan",
146 "Motherboard Fan",
147 "Video Fan",
148 "Power Supply Fan",
149 "Chipset Fan",
150 "Other Fan",
151};
152
153static const char * const docking_labels[] = {
154 "Docking Processor Fan",
155 "Docking Motherboard Fan",
156 "Docking Video Fan",
157 "Docking Power Supply Fan",
158 "Docking Chipset Fan",
159 "Docking Other Fan",
160};
161
162static inline const char __init *i8k_get_dmi_data(int field)
163{
164 const char *dmi_data = dmi_get_system_info(field);
165
166 return dmi_data && *dmi_data ? dmi_data : "?";
167}
168
169/*
170 * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
171 */
172static int i8k_smm_func(void *par)
173{
174 ktime_t calltime = ktime_get();
175 struct smm_regs *regs = par;
176 int eax = regs->eax;
177 int ebx = regs->ebx;
178 unsigned char carry;
179 long long duration;
180
181 /* SMM requires CPU 0 */
182 if (smp_processor_id() != 0)
183 return -EBUSY;
184
185 asm volatile("out %%al,$0xb2\n\t"
186 "out %%al,$0x84\n\t"
187 "setc %0\n"
188 : "=mr" (carry),
189 "+a" (regs->eax),
190 "+b" (regs->ebx),
191 "+c" (regs->ecx),
192 "+d" (regs->edx),
193 "+S" (regs->esi),
194 "+D" (regs->edi));
195
196 duration = ktime_us_delta(later: ktime_get(), earlier: calltime);
197 pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x carry: %d (took %7lld usecs)\n",
198 eax, ebx, regs->eax & 0xffff, carry, duration);
199
200 if (duration > DELL_SMM_MAX_DURATION)
201 pr_warn_once("SMM call took %lld usecs!\n", duration);
202
203 if (carry || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
204 return -EINVAL;
205
206 return 0;
207}
208
209/*
210 * Call the System Management Mode BIOS.
211 */
212static int i8k_smm(struct smm_regs *regs)
213{
214 int ret;
215
216 cpus_read_lock();
217 ret = smp_call_on_cpu(cpu: 0, func: i8k_smm_func, par: regs, phys: true);
218 cpus_read_unlock();
219
220 return ret;
221}
222
223/*
224 * Read the fan status.
225 */
226static int i8k_get_fan_status(const struct dell_smm_data *data, u8 fan)
227{
228 struct smm_regs regs = {
229 .eax = I8K_SMM_GET_FAN,
230 .ebx = fan,
231 };
232
233 if (data->disallow_fan_support)
234 return -EINVAL;
235
236 return i8k_smm(regs: &regs) ? : regs.eax & 0xff;
237}
238
239/*
240 * Read the fan speed in RPM.
241 */
242static int i8k_get_fan_speed(const struct dell_smm_data *data, u8 fan)
243{
244 struct smm_regs regs = {
245 .eax = I8K_SMM_GET_SPEED,
246 .ebx = fan,
247 };
248
249 if (data->disallow_fan_support)
250 return -EINVAL;
251
252 return i8k_smm(regs: &regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
253}
254
255/*
256 * Read the fan type.
257 */
258static int _i8k_get_fan_type(const struct dell_smm_data *data, u8 fan)
259{
260 struct smm_regs regs = {
261 .eax = I8K_SMM_GET_FAN_TYPE,
262 .ebx = fan,
263 };
264
265 if (data->disallow_fan_support || data->disallow_fan_type_call)
266 return -EINVAL;
267
268 return i8k_smm(regs: &regs) ? : regs.eax & 0xff;
269}
270
271static int i8k_get_fan_type(struct dell_smm_data *data, u8 fan)
272{
273 /* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
274 if (data->fan_type[fan] == INT_MIN)
275 data->fan_type[fan] = _i8k_get_fan_type(data, fan);
276
277 return data->fan_type[fan];
278}
279
280/*
281 * Read the fan nominal rpm for specific fan speed.
282 */
283static int __init i8k_get_fan_nominal_speed(const struct dell_smm_data *data, u8 fan, int speed)
284{
285 struct smm_regs regs = {
286 .eax = I8K_SMM_GET_NOM_SPEED,
287 .ebx = fan | (speed << 8),
288 };
289
290 if (data->disallow_fan_support)
291 return -EINVAL;
292
293 return i8k_smm(regs: &regs) ? : (regs.eax & 0xffff);
294}
295
296/*
297 * Enable or disable automatic BIOS fan control support
298 */
299static int i8k_enable_fan_auto_mode(const struct dell_smm_data *data, bool enable)
300{
301 struct smm_regs regs = { };
302
303 if (data->disallow_fan_support)
304 return -EINVAL;
305
306 regs.eax = enable ? data->auto_fan : data->manual_fan;
307 return i8k_smm(regs: &regs);
308}
309
310/*
311 * Set the fan speed (off, low, high, ...).
312 */
313static int i8k_set_fan(const struct dell_smm_data *data, u8 fan, int speed)
314{
315 struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
316
317 if (data->disallow_fan_support)
318 return -EINVAL;
319
320 speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
321 regs.ebx = fan | (speed << 8);
322
323 return i8k_smm(regs: &regs);
324}
325
326static int __init i8k_get_temp_type(u8 sensor)
327{
328 struct smm_regs regs = {
329 .eax = I8K_SMM_GET_TEMP_TYPE,
330 .ebx = sensor,
331 };
332
333 return i8k_smm(regs: &regs) ? : regs.eax & 0xff;
334}
335
336/*
337 * Read the cpu temperature.
338 */
339static int _i8k_get_temp(u8 sensor)
340{
341 struct smm_regs regs = {
342 .eax = I8K_SMM_GET_TEMP,
343 .ebx = sensor,
344 };
345
346 return i8k_smm(regs: &regs) ? : regs.eax & 0xff;
347}
348
349static int i8k_get_temp(u8 sensor)
350{
351 int temp = _i8k_get_temp(sensor);
352
353 /*
354 * Sometimes the temperature sensor returns 0x99, which is out of range.
355 * In this case we retry (once) before returning an error.
356 # 1003655137 00000058 00005a4b
357 # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
358 # 1003655139 00000054 00005c52
359 */
360 if (temp == 0x99) {
361 msleep(msecs: 100);
362 temp = _i8k_get_temp(sensor);
363 }
364 /*
365 * Return -ENODATA for all invalid temperatures.
366 *
367 * Known instances are the 0x99 value as seen above as well as
368 * 0xc1 (193), which may be returned when trying to read the GPU
369 * temperature if the system supports a GPU and it is currently
370 * turned off.
371 */
372 if (temp > I8K_MAX_TEMP)
373 return -ENODATA;
374
375 return temp;
376}
377
378static int __init i8k_get_dell_signature(int req_fn)
379{
380 struct smm_regs regs = { .eax = req_fn, };
381 int rc;
382
383 rc = i8k_smm(regs: &regs);
384 if (rc < 0)
385 return rc;
386
387 return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
388}
389
390#if IS_ENABLED(CONFIG_I8K)
391
392/*
393 * Read the Fn key status.
394 */
395static int i8k_get_fn_status(void)
396{
397 struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
398 int rc;
399
400 rc = i8k_smm(regs: &regs);
401 if (rc < 0)
402 return rc;
403
404 switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
405 case I8K_FN_UP:
406 return I8K_VOL_UP;
407 case I8K_FN_DOWN:
408 return I8K_VOL_DOWN;
409 case I8K_FN_MUTE:
410 return I8K_VOL_MUTE;
411 default:
412 return 0;
413 }
414}
415
416/*
417 * Read the power status.
418 */
419static int i8k_get_power_status(void)
420{
421 struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
422 int rc;
423
424 rc = i8k_smm(regs: &regs);
425 if (rc < 0)
426 return rc;
427
428 return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
429}
430
431/*
432 * Procfs interface
433 */
434
435static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
436{
437 struct dell_smm_data *data = pde_data(inode: file_inode(f: fp));
438 int __user *argp = (int __user *)arg;
439 int speed, err;
440 int val = 0;
441
442 if (!argp)
443 return -EINVAL;
444
445 switch (cmd) {
446 case I8K_BIOS_VERSION:
447 if (!isdigit(c: data->bios_version[0]) || !isdigit(c: data->bios_version[1]) ||
448 !isdigit(c: data->bios_version[2]))
449 return -EINVAL;
450
451 val = (data->bios_version[0] << 16) |
452 (data->bios_version[1] << 8) | data->bios_version[2];
453
454 if (copy_to_user(to: argp, from: &val, n: sizeof(val)))
455 return -EFAULT;
456
457 return 0;
458 case I8K_MACHINE_ID:
459 if (restricted && !capable(CAP_SYS_ADMIN))
460 return -EPERM;
461
462 if (copy_to_user(to: argp, from: data->bios_machineid, n: sizeof(data->bios_machineid)))
463 return -EFAULT;
464
465 return 0;
466 case I8K_FN_STATUS:
467 val = i8k_get_fn_status();
468 break;
469
470 case I8K_POWER_STATUS:
471 val = i8k_get_power_status();
472 break;
473
474 case I8K_GET_TEMP:
475 val = i8k_get_temp(sensor: 0);
476 break;
477
478 case I8K_GET_SPEED:
479 if (copy_from_user(to: &val, from: argp, n: sizeof(int)))
480 return -EFAULT;
481
482 if (val > U8_MAX || val < 0)
483 return -EINVAL;
484
485 val = i8k_get_fan_speed(data, fan: val);
486 break;
487
488 case I8K_GET_FAN:
489 if (copy_from_user(to: &val, from: argp, n: sizeof(int)))
490 return -EFAULT;
491
492 if (val > U8_MAX || val < 0)
493 return -EINVAL;
494
495 val = i8k_get_fan_status(data, fan: val);
496 break;
497
498 case I8K_SET_FAN:
499 if (restricted && !capable(CAP_SYS_ADMIN))
500 return -EPERM;
501
502 if (copy_from_user(to: &val, from: argp, n: sizeof(int)))
503 return -EFAULT;
504
505 if (val > U8_MAX || val < 0)
506 return -EINVAL;
507
508 if (copy_from_user(to: &speed, from: argp + 1, n: sizeof(int)))
509 return -EFAULT;
510
511 mutex_lock(&data->i8k_mutex);
512 err = i8k_set_fan(data, fan: val, speed);
513 if (err < 0)
514 val = err;
515 else
516 val = i8k_get_fan_status(data, fan: val);
517 mutex_unlock(lock: &data->i8k_mutex);
518 break;
519
520 default:
521 return -ENOIOCTLCMD;
522 }
523
524 if (val < 0)
525 return val;
526
527 if (copy_to_user(to: argp, from: &val, n: sizeof(int)))
528 return -EFAULT;
529
530 return 0;
531}
532
533/*
534 * Print the information for /proc/i8k.
535 */
536static int i8k_proc_show(struct seq_file *seq, void *offset)
537{
538 struct dell_smm_data *data = seq->private;
539 int fn_key, cpu_temp, ac_power;
540 int left_fan, right_fan, left_speed, right_speed;
541
542 cpu_temp = i8k_get_temp(sensor: 0); /* 11100 µs */
543 left_fan = i8k_get_fan_status(data, I8K_FAN_LEFT); /* 580 µs */
544 right_fan = i8k_get_fan_status(data, I8K_FAN_RIGHT); /* 580 µs */
545 left_speed = i8k_get_fan_speed(data, I8K_FAN_LEFT); /* 580 µs */
546 right_speed = i8k_get_fan_speed(data, I8K_FAN_RIGHT); /* 580 µs */
547 fn_key = i8k_get_fn_status(); /* 750 µs */
548 if (power_status)
549 ac_power = i8k_get_power_status(); /* 14700 µs */
550 else
551 ac_power = -1;
552
553 /*
554 * Info:
555 *
556 * 1) Format version (this will change if format changes)
557 * 2) BIOS version
558 * 3) BIOS machine ID
559 * 4) Cpu temperature
560 * 5) Left fan status
561 * 6) Right fan status
562 * 7) Left fan speed
563 * 8) Right fan speed
564 * 9) AC power
565 * 10) Fn Key status
566 */
567 seq_printf(m: seq, fmt: "%s %s %s %d %d %d %d %d %d %d\n",
568 I8K_PROC_FMT,
569 data->bios_version,
570 (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : data->bios_machineid,
571 cpu_temp,
572 left_fan, right_fan, left_speed, right_speed,
573 ac_power, fn_key);
574
575 return 0;
576}
577
578static int i8k_open_fs(struct inode *inode, struct file *file)
579{
580 return single_open(file, i8k_proc_show, pde_data(inode));
581}
582
583static const struct proc_ops i8k_proc_ops = {
584 .proc_open = i8k_open_fs,
585 .proc_read = seq_read,
586 .proc_lseek = seq_lseek,
587 .proc_release = single_release,
588 .proc_ioctl = i8k_ioctl,
589};
590
591static void i8k_exit_procfs(void *param)
592{
593 remove_proc_entry("i8k", NULL);
594}
595
596static void __init i8k_init_procfs(struct device *dev)
597{
598 struct dell_smm_data *data = dev_get_drvdata(dev);
599
600 /* Only register exit function if creation was successful */
601 if (proc_create_data("i8k", 0, NULL, &i8k_proc_ops, data))
602 devm_add_action_or_reset(dev, i8k_exit_procfs, NULL);
603}
604
605#else
606
607static void __init i8k_init_procfs(struct device *dev)
608{
609}
610
611#endif
612
613static int dell_smm_get_max_state(struct thermal_cooling_device *dev, unsigned long *state)
614{
615 struct dell_smm_cooling_data *cdata = dev->devdata;
616
617 *state = cdata->data->i8k_fan_max;
618
619 return 0;
620}
621
622static int dell_smm_get_cur_state(struct thermal_cooling_device *dev, unsigned long *state)
623{
624 struct dell_smm_cooling_data *cdata = dev->devdata;
625 int ret;
626
627 ret = i8k_get_fan_status(data: cdata->data, fan: cdata->fan_num);
628 if (ret < 0)
629 return ret;
630
631 *state = ret;
632
633 return 0;
634}
635
636static int dell_smm_set_cur_state(struct thermal_cooling_device *dev, unsigned long state)
637{
638 struct dell_smm_cooling_data *cdata = dev->devdata;
639 struct dell_smm_data *data = cdata->data;
640 int ret;
641
642 if (state > data->i8k_fan_max)
643 return -EINVAL;
644
645 mutex_lock(&data->i8k_mutex);
646 ret = i8k_set_fan(data, fan: cdata->fan_num, speed: (int)state);
647 mutex_unlock(lock: &data->i8k_mutex);
648
649 return ret;
650}
651
652static const struct thermal_cooling_device_ops dell_smm_cooling_ops = {
653 .get_max_state = dell_smm_get_max_state,
654 .get_cur_state = dell_smm_get_cur_state,
655 .set_cur_state = dell_smm_set_cur_state,
656};
657
658static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
659 int channel)
660{
661 const struct dell_smm_data *data = drvdata;
662
663 switch (type) {
664 case hwmon_temp:
665 switch (attr) {
666 case hwmon_temp_input:
667 /* _i8k_get_temp() is fine since we do not care about the actual value */
668 if (data->temp_type[channel] >= 0 || _i8k_get_temp(sensor: channel) >= 0)
669 return 0444;
670
671 break;
672 case hwmon_temp_label:
673 if (data->temp_type[channel] >= 0)
674 return 0444;
675
676 break;
677 default:
678 break;
679 }
680 break;
681 case hwmon_fan:
682 if (data->disallow_fan_support)
683 break;
684
685 switch (attr) {
686 case hwmon_fan_input:
687 if (data->fan[channel])
688 return 0444;
689
690 break;
691 case hwmon_fan_label:
692 if (data->fan[channel] && !data->disallow_fan_type_call)
693 return 0444;
694
695 break;
696 case hwmon_fan_min:
697 case hwmon_fan_max:
698 case hwmon_fan_target:
699 if (data->fan_nominal_speed[channel])
700 return 0444;
701
702 break;
703 default:
704 break;
705 }
706 break;
707 case hwmon_pwm:
708 if (data->disallow_fan_support)
709 break;
710
711 switch (attr) {
712 case hwmon_pwm_input:
713 if (data->fan[channel])
714 return 0644;
715
716 break;
717 case hwmon_pwm_enable:
718 if (data->auto_fan)
719 /*
720 * There is no command for retrieve the current status
721 * from BIOS, and userspace/firmware itself can change
722 * it.
723 * Thus we can only provide write-only access for now.
724 */
725 return 0200;
726
727 break;
728 default:
729 break;
730 }
731 break;
732 default:
733 break;
734 }
735
736 return 0;
737}
738
739static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
740 long *val)
741{
742 struct dell_smm_data *data = dev_get_drvdata(dev);
743 int mult = data->i8k_fan_mult;
744 int ret;
745
746 switch (type) {
747 case hwmon_temp:
748 switch (attr) {
749 case hwmon_temp_input:
750 ret = i8k_get_temp(sensor: channel);
751 if (ret < 0)
752 return ret;
753
754 *val = ret * 1000;
755
756 return 0;
757 default:
758 break;
759 }
760 break;
761 case hwmon_fan:
762 switch (attr) {
763 case hwmon_fan_input:
764 ret = i8k_get_fan_speed(data, fan: channel);
765 if (ret < 0)
766 return ret;
767
768 *val = ret;
769
770 return 0;
771 case hwmon_fan_min:
772 *val = data->fan_nominal_speed[channel][0] * mult;
773
774 return 0;
775 case hwmon_fan_max:
776 *val = data->fan_nominal_speed[channel][data->i8k_fan_max] * mult;
777
778 return 0;
779 case hwmon_fan_target:
780 ret = i8k_get_fan_status(data, fan: channel);
781 if (ret < 0)
782 return ret;
783
784 if (ret > data->i8k_fan_max)
785 ret = data->i8k_fan_max;
786
787 *val = data->fan_nominal_speed[channel][ret] * mult;
788
789 return 0;
790 default:
791 break;
792 }
793 break;
794 case hwmon_pwm:
795 switch (attr) {
796 case hwmon_pwm_input:
797 ret = i8k_get_fan_status(data, fan: channel);
798 if (ret < 0)
799 return ret;
800
801 *val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);
802
803 return 0;
804 default:
805 break;
806 }
807 break;
808 default:
809 break;
810 }
811
812 return -EOPNOTSUPP;
813}
814
815static const char *dell_smm_fan_label(struct dell_smm_data *data, int channel)
816{
817 bool dock = false;
818 int type = i8k_get_fan_type(data, fan: channel);
819
820 if (type < 0)
821 return ERR_PTR(error: type);
822
823 if (type & 0x10) {
824 dock = true;
825 type &= 0x0F;
826 }
827
828 if (type >= ARRAY_SIZE(fan_labels))
829 type = ARRAY_SIZE(fan_labels) - 1;
830
831 return dock ? docking_labels[type] : fan_labels[type];
832}
833
834static int dell_smm_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
835 int channel, const char **str)
836{
837 struct dell_smm_data *data = dev_get_drvdata(dev);
838
839 switch (type) {
840 case hwmon_temp:
841 switch (attr) {
842 case hwmon_temp_label:
843 *str = temp_labels[data->temp_type[channel]];
844 return 0;
845 default:
846 break;
847 }
848 break;
849 case hwmon_fan:
850 switch (attr) {
851 case hwmon_fan_label:
852 *str = dell_smm_fan_label(data, channel);
853 return PTR_ERR_OR_ZERO(ptr: *str);
854 default:
855 break;
856 }
857 break;
858 default:
859 break;
860 }
861
862 return -EOPNOTSUPP;
863}
864
865static int dell_smm_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
866 long val)
867{
868 struct dell_smm_data *data = dev_get_drvdata(dev);
869 unsigned long pwm;
870 bool enable;
871 int err;
872
873 switch (type) {
874 case hwmon_pwm:
875 switch (attr) {
876 case hwmon_pwm_input:
877 pwm = clamp_val(DIV_ROUND_CLOSEST(val, data->i8k_pwm_mult), 0,
878 data->i8k_fan_max);
879
880 mutex_lock(&data->i8k_mutex);
881 err = i8k_set_fan(data, fan: channel, speed: pwm);
882 mutex_unlock(lock: &data->i8k_mutex);
883
884 if (err < 0)
885 return err;
886
887 return 0;
888 case hwmon_pwm_enable:
889 if (!val)
890 return -EINVAL;
891
892 if (val == 1)
893 enable = false;
894 else
895 enable = true;
896
897 mutex_lock(&data->i8k_mutex);
898 err = i8k_enable_fan_auto_mode(data, enable);
899 mutex_unlock(lock: &data->i8k_mutex);
900
901 if (err < 0)
902 return err;
903
904 return 0;
905 default:
906 break;
907 }
908 break;
909 default:
910 break;
911 }
912
913 return -EOPNOTSUPP;
914}
915
916static const struct hwmon_ops dell_smm_ops = {
917 .is_visible = dell_smm_is_visible,
918 .read = dell_smm_read,
919 .read_string = dell_smm_read_string,
920 .write = dell_smm_write,
921};
922
923static const struct hwmon_channel_info * const dell_smm_info[] = {
924 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
925 HWMON_CHANNEL_INFO(temp,
926 HWMON_T_INPUT | HWMON_T_LABEL,
927 HWMON_T_INPUT | HWMON_T_LABEL,
928 HWMON_T_INPUT | HWMON_T_LABEL,
929 HWMON_T_INPUT | HWMON_T_LABEL,
930 HWMON_T_INPUT | HWMON_T_LABEL,
931 HWMON_T_INPUT | HWMON_T_LABEL,
932 HWMON_T_INPUT | HWMON_T_LABEL,
933 HWMON_T_INPUT | HWMON_T_LABEL,
934 HWMON_T_INPUT | HWMON_T_LABEL,
935 HWMON_T_INPUT | HWMON_T_LABEL
936 ),
937 HWMON_CHANNEL_INFO(fan,
938 HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
939 HWMON_F_TARGET,
940 HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
941 HWMON_F_TARGET,
942 HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_MIN | HWMON_F_MAX |
943 HWMON_F_TARGET
944 ),
945 HWMON_CHANNEL_INFO(pwm,
946 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
947 HWMON_PWM_INPUT,
948 HWMON_PWM_INPUT
949 ),
950 NULL
951};
952
953static const struct hwmon_chip_info dell_smm_chip_info = {
954 .ops = &dell_smm_ops,
955 .info = dell_smm_info,
956};
957
958static int __init dell_smm_init_cdev(struct device *dev, u8 fan_num)
959{
960 struct dell_smm_data *data = dev_get_drvdata(dev);
961 struct thermal_cooling_device *cdev;
962 struct dell_smm_cooling_data *cdata;
963 int ret = 0;
964 char *name;
965
966 name = kasprintf(GFP_KERNEL, fmt: "dell-smm-fan%u", fan_num + 1);
967 if (!name)
968 return -ENOMEM;
969
970 cdata = devm_kmalloc(dev, size: sizeof(*cdata), GFP_KERNEL);
971 if (cdata) {
972 cdata->fan_num = fan_num;
973 cdata->data = data;
974 cdev = devm_thermal_of_cooling_device_register(dev, NULL, type: name, devdata: cdata,
975 ops: &dell_smm_cooling_ops);
976 if (IS_ERR(ptr: cdev)) {
977 devm_kfree(dev, p: cdata);
978 ret = PTR_ERR(ptr: cdev);
979 }
980 } else {
981 ret = -ENOMEM;
982 }
983
984 kfree(objp: name);
985
986 return ret;
987}
988
989static int __init dell_smm_init_hwmon(struct device *dev)
990{
991 struct dell_smm_data *data = dev_get_drvdata(dev);
992 struct device *dell_smm_hwmon_dev;
993 int state, err;
994 u8 i;
995
996 for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
997 data->temp_type[i] = i8k_get_temp_type(sensor: i);
998 if (data->temp_type[i] < 0)
999 continue;
1000
1001 if (data->temp_type[i] >= ARRAY_SIZE(temp_labels))
1002 data->temp_type[i] = ARRAY_SIZE(temp_labels) - 1;
1003 }
1004
1005 for (i = 0; i < DELL_SMM_NO_FANS; i++) {
1006 data->fan_type[i] = INT_MIN;
1007 err = i8k_get_fan_status(data, fan: i);
1008 if (err < 0)
1009 err = i8k_get_fan_type(data, fan: i);
1010
1011 if (err < 0)
1012 continue;
1013
1014 data->fan[i] = true;
1015
1016 /* the cooling device is not critical, ignore failures */
1017 if (IS_REACHABLE(CONFIG_THERMAL)) {
1018 err = dell_smm_init_cdev(dev, fan_num: i);
1019 if (err < 0)
1020 dev_warn(dev, "Failed to register cooling device for fan %u\n",
1021 i + 1);
1022 }
1023
1024 data->fan_nominal_speed[i] = devm_kmalloc_array(dev, n: data->i8k_fan_max + 1,
1025 size: sizeof(*data->fan_nominal_speed[i]),
1026 GFP_KERNEL);
1027 if (!data->fan_nominal_speed[i])
1028 continue;
1029
1030 for (state = 0; state <= data->i8k_fan_max; state++) {
1031 err = i8k_get_fan_nominal_speed(data, fan: i, speed: state);
1032 if (err < 0) {
1033 /* Mark nominal speed table as invalid in case of error */
1034 devm_kfree(dev, p: data->fan_nominal_speed[i]);
1035 data->fan_nominal_speed[i] = NULL;
1036 break;
1037 }
1038 data->fan_nominal_speed[i][state] = err;
1039 /*
1040 * Autodetect fan multiplier based on nominal rpm if multiplier
1041 * was not specified as module param or in DMI. If fan reports
1042 * rpm value too high then set multiplier to 1.
1043 */
1044 if (!fan_mult && err > I8K_FAN_RPM_THRESHOLD)
1045 data->i8k_fan_mult = 1;
1046 }
1047 }
1048
1049 dell_smm_hwmon_dev = devm_hwmon_device_register_with_info(dev, name: "dell_smm", drvdata: data,
1050 info: &dell_smm_chip_info, NULL);
1051
1052 return PTR_ERR_OR_ZERO(ptr: dell_smm_hwmon_dev);
1053}
1054
1055struct i8k_config_data {
1056 uint fan_mult;
1057 uint fan_max;
1058};
1059
1060enum i8k_configs {
1061 DELL_LATITUDE_D520,
1062 DELL_PRECISION_490,
1063 DELL_STUDIO,
1064 DELL_XPS,
1065};
1066
1067/*
1068 * Only use for machines which need some special configuration
1069 * in order to work correctly (e.g. if autoconfig fails on this machines).
1070 */
1071
1072static const struct i8k_config_data i8k_config_data[] __initconst = {
1073 [DELL_LATITUDE_D520] = {
1074 .fan_mult = 1,
1075 .fan_max = I8K_FAN_TURBO,
1076 },
1077 [DELL_PRECISION_490] = {
1078 .fan_mult = 1,
1079 .fan_max = I8K_FAN_TURBO,
1080 },
1081 [DELL_STUDIO] = {
1082 .fan_mult = 1,
1083 .fan_max = I8K_FAN_HIGH,
1084 },
1085 [DELL_XPS] = {
1086 .fan_mult = 1,
1087 .fan_max = I8K_FAN_HIGH,
1088 },
1089};
1090
1091static const struct dmi_system_id i8k_dmi_table[] __initconst = {
1092 {
1093 .ident = "Dell G5 5590",
1094 .matches = {
1095 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1096 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "G5 5590"),
1097 },
1098 },
1099 {
1100 .ident = "Dell Inspiron",
1101 .matches = {
1102 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
1103 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
1104 },
1105 },
1106 {
1107 .ident = "Dell Latitude",
1108 .matches = {
1109 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
1110 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1111 },
1112 },
1113 {
1114 .ident = "Dell Inspiron 2",
1115 .matches = {
1116 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1117 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
1118 },
1119 },
1120 {
1121 .ident = "Dell Latitude D520",
1122 .matches = {
1123 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1124 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
1125 },
1126 .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
1127 },
1128 {
1129 .ident = "Dell Latitude 2",
1130 .matches = {
1131 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1132 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1133 },
1134 },
1135 { /* UK Inspiron 6400 */
1136 .ident = "Dell Inspiron 3",
1137 .matches = {
1138 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1139 DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
1140 },
1141 },
1142 {
1143 .ident = "Dell Inspiron 3",
1144 .matches = {
1145 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1146 DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
1147 },
1148 },
1149 {
1150 .ident = "Dell Precision 490",
1151 .matches = {
1152 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1153 DMI_MATCH(DMI_PRODUCT_NAME,
1154 "Precision WorkStation 490"),
1155 },
1156 .driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
1157 },
1158 {
1159 .ident = "Dell Precision",
1160 .matches = {
1161 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1162 DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
1163 },
1164 },
1165 {
1166 .ident = "Dell Vostro",
1167 .matches = {
1168 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1169 DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
1170 },
1171 },
1172 {
1173 .ident = "Dell Studio",
1174 .matches = {
1175 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1176 DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
1177 },
1178 .driver_data = (void *)&i8k_config_data[DELL_STUDIO],
1179 },
1180 {
1181 .ident = "Dell XPS M140",
1182 .matches = {
1183 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1184 DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
1185 },
1186 .driver_data = (void *)&i8k_config_data[DELL_XPS],
1187 },
1188 {
1189 .ident = "Dell XPS",
1190 .matches = {
1191 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1192 DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
1193 },
1194 },
1195 { }
1196};
1197
1198MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
1199
1200/*
1201 * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
1202 * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
1203 * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
1204 * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
1205 */
1206static const struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initconst = {
1207 {
1208 .ident = "Dell Studio XPS 8000",
1209 .matches = {
1210 DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1211 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
1212 },
1213 },
1214 {
1215 .ident = "Dell Studio XPS 8100",
1216 .matches = {
1217 DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1218 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
1219 },
1220 },
1221 {
1222 .ident = "Dell Inspiron 580",
1223 .matches = {
1224 DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1225 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
1226 },
1227 },
1228 {
1229 .ident = "Dell Inspiron 3505",
1230 .matches = {
1231 DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1232 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 3505"),
1233 },
1234 },
1235 { }
1236};
1237
1238/*
1239 * On some machines all fan related SMM functions implemented by Dell BIOS
1240 * firmware freeze kernel for about 500ms. Until Dell fixes these problems fan
1241 * support for affected blacklisted Dell machines stay disabled.
1242 * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=195751
1243 */
1244static const struct dmi_system_id i8k_blacklist_fan_support_dmi_table[] __initconst = {
1245 {
1246 .ident = "Dell Inspiron 7720",
1247 .matches = {
1248 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1249 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
1250 },
1251 },
1252 {
1253 .ident = "Dell Vostro 3360",
1254 .matches = {
1255 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1256 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
1257 },
1258 },
1259 {
1260 .ident = "Dell XPS13 9333",
1261 .matches = {
1262 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1263 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
1264 },
1265 },
1266 {
1267 .ident = "Dell XPS 15 L502X",
1268 .matches = {
1269 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1270 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L502X"),
1271 },
1272 },
1273 { }
1274};
1275
1276struct i8k_fan_control_data {
1277 unsigned int manual_fan;
1278 unsigned int auto_fan;
1279};
1280
1281enum i8k_fan_controls {
1282 I8K_FAN_34A3_35A3,
1283};
1284
1285static const struct i8k_fan_control_data i8k_fan_control_data[] __initconst = {
1286 [I8K_FAN_34A3_35A3] = {
1287 .manual_fan = 0x34a3,
1288 .auto_fan = 0x35a3,
1289 },
1290};
1291
1292static const struct dmi_system_id i8k_whitelist_fan_control[] __initconst = {
1293 {
1294 .ident = "Dell Latitude 5480",
1295 .matches = {
1296 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1297 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5480"),
1298 },
1299 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1300 },
1301 {
1302 .ident = "Dell Latitude E6440",
1303 .matches = {
1304 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1305 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
1306 },
1307 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1308 },
1309 {
1310 .ident = "Dell Latitude E7440",
1311 .matches = {
1312 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1313 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E7440"),
1314 },
1315 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1316 },
1317 {
1318 .ident = "Dell Precision 5530",
1319 .matches = {
1320 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1321 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
1322 },
1323 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1324 },
1325 {
1326 .ident = "Dell Precision 7510",
1327 .matches = {
1328 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1329 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
1330 },
1331 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1332 },
1333 {
1334 .ident = "Dell XPS 13 7390",
1335 .matches = {
1336 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1337 DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS 13 7390"),
1338 },
1339 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1340 },
1341 { }
1342};
1343
1344static int __init dell_smm_probe(struct platform_device *pdev)
1345{
1346 struct dell_smm_data *data;
1347 const struct dmi_system_id *id, *fan_control;
1348 int ret;
1349
1350 data = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct dell_smm_data), GFP_KERNEL);
1351 if (!data)
1352 return -ENOMEM;
1353
1354 mutex_init(&data->i8k_mutex);
1355 platform_set_drvdata(pdev, data);
1356
1357 if (dmi_check_system(list: i8k_blacklist_fan_support_dmi_table)) {
1358 if (!force) {
1359 dev_notice(&pdev->dev, "Disabling fan support due to BIOS bugs\n");
1360 data->disallow_fan_support = true;
1361 } else {
1362 dev_warn(&pdev->dev, "Enabling fan support despite BIOS bugs\n");
1363 }
1364 }
1365
1366 if (dmi_check_system(list: i8k_blacklist_fan_type_dmi_table)) {
1367 if (!force) {
1368 dev_notice(&pdev->dev, "Disabling fan type call due to BIOS bugs\n");
1369 data->disallow_fan_type_call = true;
1370 } else {
1371 dev_warn(&pdev->dev, "Enabling fan type call despite BIOS bugs\n");
1372 }
1373 }
1374
1375 strscpy(p: data->bios_version, q: i8k_get_dmi_data(field: DMI_BIOS_VERSION),
1376 size: sizeof(data->bios_version));
1377 strscpy(p: data->bios_machineid, q: i8k_get_dmi_data(field: DMI_PRODUCT_SERIAL),
1378 size: sizeof(data->bios_machineid));
1379
1380 /*
1381 * Set fan multiplier and maximal fan speed from dmi config
1382 * Values specified in module parameters override values from dmi
1383 */
1384 id = dmi_first_match(list: i8k_dmi_table);
1385 if (id && id->driver_data) {
1386 const struct i8k_config_data *conf = id->driver_data;
1387
1388 if (!fan_mult && conf->fan_mult)
1389 fan_mult = conf->fan_mult;
1390
1391 if (!fan_max && conf->fan_max)
1392 fan_max = conf->fan_max;
1393 }
1394
1395 /* All options must not be 0 */
1396 data->i8k_fan_mult = fan_mult ? : I8K_FAN_MULT;
1397 data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH;
1398 data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max);
1399
1400 fan_control = dmi_first_match(list: i8k_whitelist_fan_control);
1401 if (fan_control && fan_control->driver_data) {
1402 const struct i8k_fan_control_data *control = fan_control->driver_data;
1403
1404 data->manual_fan = control->manual_fan;
1405 data->auto_fan = control->auto_fan;
1406 dev_info(&pdev->dev, "enabling support for setting automatic/manual fan control\n");
1407 }
1408
1409 ret = dell_smm_init_hwmon(dev: &pdev->dev);
1410 if (ret)
1411 return ret;
1412
1413 i8k_init_procfs(dev: &pdev->dev);
1414
1415 return 0;
1416}
1417
1418static struct platform_driver dell_smm_driver = {
1419 .driver = {
1420 .name = KBUILD_MODNAME,
1421 },
1422};
1423
1424static struct platform_device *dell_smm_device;
1425
1426/*
1427 * Probe for the presence of a supported laptop.
1428 */
1429static int __init i8k_init(void)
1430{
1431 /*
1432 * Get DMI information
1433 */
1434 if (!dmi_check_system(list: i8k_dmi_table)) {
1435 if (!ignore_dmi && !force)
1436 return -ENODEV;
1437
1438 pr_info("not running on a supported Dell system.\n");
1439 pr_info("vendor=%s, model=%s, version=%s\n",
1440 i8k_get_dmi_data(DMI_SYS_VENDOR),
1441 i8k_get_dmi_data(DMI_PRODUCT_NAME),
1442 i8k_get_dmi_data(DMI_BIOS_VERSION));
1443 }
1444
1445 /*
1446 * Get SMM Dell signature
1447 */
1448 if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
1449 i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
1450 if (!force)
1451 return -ENODEV;
1452
1453 pr_err("Unable to get Dell SMM signature\n");
1454 }
1455
1456 dell_smm_device = platform_create_bundle(&dell_smm_driver, dell_smm_probe, NULL, 0, NULL,
1457 0);
1458
1459 return PTR_ERR_OR_ZERO(ptr: dell_smm_device);
1460}
1461
1462static void __exit i8k_exit(void)
1463{
1464 platform_device_unregister(dell_smm_device);
1465 platform_driver_unregister(&dell_smm_driver);
1466}
1467
1468module_init(i8k_init);
1469module_exit(i8k_exit);
1470

source code of linux/drivers/hwmon/dell-smm-hwmon.c