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