drivers/hwmon/dell-smm-hwmon.c

   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/cpu.h>
  16 #include <linux/delay.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/types.h>
  21 #include <linux/init.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/dmi.h>
  25 #include <linux/capability.h>
  26 #include <linux/mutex.h>
  27 #include <linux/hwmon.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/io.h>
  30 #include <linux/sched.h>
  31 #include <linux/ctype.h>
  32 #include <linux/smp.h>
  33
  34 #include <linux/i8k.h>
  35
  36 #define I8K_SMM_FN_STATUS       0x0025
  37 #define I8K_SMM_POWER_STATUS    0x0069
  38 #define I8K_SMM_SET_FAN         0x01a3
  39 #define I8K_SMM_GET_FAN         0x00a3
  40 #define I8K_SMM_GET_SPEED       0x02a3
  41 #define I8K_SMM_GET_FAN_TYPE    0x03a3
  42 #define I8K_SMM_GET_NOM_SPEED   0x04a3
  43 #define I8K_SMM_GET_TEMP        0x10a3
  44 #define I8K_SMM_GET_TEMP_TYPE   0x11a3
  45 #define I8K_SMM_GET_DELL_SIG1   0xfea3
  46 #define I8K_SMM_GET_DELL_SIG2   0xffa3
  47
  48 #define I8K_FAN_MULT            30
  49 #define I8K_FAN_MAX_RPM         30000
  50 #define I8K_MAX_TEMP            127
  51
  52 #define I8K_FN_NONE             0x00
  53 #define I8K_FN_UP               0x01
  54 #define I8K_FN_DOWN             0x02
  55 #define I8K_FN_MUTE             0x04
  56 #define I8K_FN_MASK             0x07
  57 #define I8K_FN_SHIFT            8
  58
  59 #define I8K_POWER_AC            0x05
  60 #define I8K_POWER_BATTERY       0x01
  61
  62 #define DELL_SMM_NO_TEMP        10
  63 #define DELL_SMM_NO_FANS        3
  64
  65 struct dell_smm_data {
  66         struct mutex i8k_mutex; /* lock for sensors writes */
  67         char bios_version[4];
  68         char bios_machineid[16];
  69         uint i8k_fan_mult;
  70         uint i8k_pwm_mult;
  71         uint i8k_fan_max;
  72         bool disallow_fan_type_call;
  73         bool disallow_fan_support;
  74         unsigned int manual_fan;
  75         unsigned int auto_fan;
  76         int temp_type[DELL_SMM_NO_TEMP];
  77         bool fan[DELL_SMM_NO_FANS];
  78         int fan_type[DELL_SMM_NO_FANS];
  79 };
  80
  81 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  82 MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
  83 MODULE_DESCRIPTION("Dell laptop SMM BIOS hwmon driver");
  84 MODULE_LICENSE("GPL");
  85 MODULE_ALIAS("i8k");
  86
  87 static bool force;
  88 module_param(force, bool, 0);
  89 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  90
  91 static bool ignore_dmi;
  92 module_param(ignore_dmi, bool, 0);
  93 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  94
  95 #if IS_ENABLED(CONFIG_I8K)
  96 static bool restricted = true;
  97 module_param(restricted, bool, 0);
  98 MODULE_PARM_DESC(restricted, "Restrict fan control and serial number to CAP_SYS_ADMIN (default: 1)");
  99
 100 static bool power_status;
 101 module_param(power_status, bool, 0600);
 102 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k (default: 0)");
 103 #endif
 104
 105 static uint fan_mult;
 106 module_param(fan_mult, uint, 0);
 107 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with (default: autodetect)");
 108
 109 static uint fan_max;
 110 module_param(fan_max, uint, 0);
 111 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed (default: autodetect)");
 112
 113 struct smm_regs {
 114         unsigned int eax;
 115         unsigned int ebx __packed;
 116         unsigned int ecx __packed;
 117         unsigned int edx __packed;
 118         unsigned int esi __packed;
 119         unsigned int edi __packed;
 120 };
 121
 122 static const char * const temp_labels[] = {
 123         "CPU",
 124         "GPU",
 125         "SODIMM",
 126         "Other",
 127         "Ambient",
 128         "Other",
 129 };
 130
 131 static const char * const fan_labels[] = {
 132         "Processor Fan",
 133         "Motherboard Fan",
 134         "Video Fan",
 135         "Power Supply Fan",
 136         "Chipset Fan",
 137         "Other Fan",
 138 };
 139
 140 static const char * const docking_labels[] = {
 141         "Docking Processor Fan",
 142         "Docking Motherboard Fan",
 143         "Docking Video Fan",
 144         "Docking Power Supply Fan",
 145         "Docking Chipset Fan",
 146         "Docking Other Fan",
 147 };
 148
 149 static inline const char __init *i8k_get_dmi_data(int field)
 150 {
 151         const char *dmi_data = dmi_get_system_info(field);
 152
 153         return dmi_data && *dmi_data ? dmi_data : "?";
 154 }
 155
 156 /*
 157  * Call the System Management Mode BIOS. Code provided by Jonathan Buzzard.
 158  */
 159 static int i8k_smm_func(void *par)
 160 {
 161         int rc;
 162         struct smm_regs *regs = par;
 163         int eax = regs->eax;
 164
 165 #ifdef DEBUG
 166         int ebx = regs->ebx;
 167         unsigned long duration;
 168         ktime_t calltime, delta, rettime;
 169
 170         calltime = ktime_get();
 171 #endif
 172
 173         /* SMM requires CPU 0 */
 174         if (smp_processor_id() != 0)
 175                 return -EBUSY;
 176
 177 #if defined(CONFIG_X86_64)
 178         asm volatile("pushq %%rax\n\t"
 179                 "movl 0(%%rax),%%edx\n\t"
 180                 "pushq %%rdx\n\t"
 181                 "movl 4(%%rax),%%ebx\n\t"
 182                 "movl 8(%%rax),%%ecx\n\t"
 183                 "movl 12(%%rax),%%edx\n\t"
 184                 "movl 16(%%rax),%%esi\n\t"
 185                 "movl 20(%%rax),%%edi\n\t"
 186                 "popq %%rax\n\t"
 187                 "out %%al,$0xb2\n\t"
 188                 "out %%al,$0x84\n\t"
 189                 "xchgq %%rax,(%%rsp)\n\t"
 190                 "movl %%ebx,4(%%rax)\n\t"
 191                 "movl %%ecx,8(%%rax)\n\t"
 192                 "movl %%edx,12(%%rax)\n\t"
 193                 "movl %%esi,16(%%rax)\n\t"
 194                 "movl %%edi,20(%%rax)\n\t"
 195                 "popq %%rdx\n\t"
 196                 "movl %%edx,0(%%rax)\n\t"
 197                 "pushfq\n\t"
 198                 "popq %%rax\n\t"
 199                 "andl $1,%%eax\n"
 200                 : "=a"(rc)
 201                 :    "a"(regs)
 202                 :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 203 #else
 204         asm volatile("pushl %%eax\n\t"
 205             "movl 0(%%eax),%%edx\n\t"
 206             "push %%edx\n\t"
 207             "movl 4(%%eax),%%ebx\n\t"
 208             "movl 8(%%eax),%%ecx\n\t"
 209             "movl 12(%%eax),%%edx\n\t"
 210             "movl 16(%%eax),%%esi\n\t"
 211             "movl 20(%%eax),%%edi\n\t"
 212             "popl %%eax\n\t"
 213             "out %%al,$0xb2\n\t"
 214             "out %%al,$0x84\n\t"
 215             "xchgl %%eax,(%%esp)\n\t"
 216             "movl %%ebx,4(%%eax)\n\t"
 217             "movl %%ecx,8(%%eax)\n\t"
 218             "movl %%edx,12(%%eax)\n\t"
 219             "movl %%esi,16(%%eax)\n\t"
 220             "movl %%edi,20(%%eax)\n\t"
 221             "popl %%edx\n\t"
 222             "movl %%edx,0(%%eax)\n\t"
 223             "lahf\n\t"
 224             "shrl $8,%%eax\n\t"
 225             "andl $1,%%eax\n"
 226             : "=a"(rc)
 227             :    "a"(regs)
 228             :    "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 229 #endif
 230         if (rc != 0 || (regs->eax & 0xffff) == 0xffff || regs->eax == eax)
 231                 rc = -EINVAL;
 232
 233 #ifdef DEBUG
 234         rettime = ktime_get();
 235         delta = ktime_sub(rettime, calltime);
 236         duration = ktime_to_ns(delta) >> 10;
 237         pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x  (took %7lu usecs)\n", eax, ebx,
 238                 (rc ? 0xffff : regs->eax & 0xffff), duration);
 239 #endif
 240
 241         return rc;
 242 }
 243
 244 /*
 245  * Call the System Management Mode BIOS.
 246  */
 247 static int i8k_smm(struct smm_regs *regs)
 248 {
 249         int ret;
 250
 251         cpus_read_lock();
 252         ret = smp_call_on_cpu(0, i8k_smm_func, regs, true);
 253         cpus_read_unlock();
 254
 255         return ret;
 256 }
 257
 258 /*
 259  * Read the fan status.
 260  */
 261 static int i8k_get_fan_status(const struct dell_smm_data *data, int fan)
 262 {
 263         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
 264
 265         if (data->disallow_fan_support)
 266                 return -EINVAL;
 267
 268         regs.ebx = fan & 0xff;
 269         return i8k_smm(&regs) ? : regs.eax & 0xff;
 270 }
 271
 272 /*
 273  * Read the fan speed in RPM.
 274  */
 275 static int i8k_get_fan_speed(const struct dell_smm_data *data, int fan)
 276 {
 277         struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 278
 279         if (data->disallow_fan_support)
 280                 return -EINVAL;
 281
 282         regs.ebx = fan & 0xff;
 283         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
 284 }
 285
 286 /*
 287  * Read the fan type.
 288  */
 289 static int _i8k_get_fan_type(const struct dell_smm_data *data, int fan)
 290 {
 291         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
 292
 293         if (data->disallow_fan_support || data->disallow_fan_type_call)
 294                 return -EINVAL;
 295
 296         regs.ebx = fan & 0xff;
 297         return i8k_smm(&regs) ? : regs.eax & 0xff;
 298 }
 299
 300 static int i8k_get_fan_type(struct dell_smm_data *data, int fan)
 301 {
 302         /* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
 303         if (data->fan_type[fan] == INT_MIN)
 304                 data->fan_type[fan] = _i8k_get_fan_type(data, fan);
 305
 306         return data->fan_type[fan];
 307 }
 308
 309 /*
 310  * Read the fan nominal rpm for specific fan speed.
 311  */
 312 static int i8k_get_fan_nominal_speed(const struct dell_smm_data *data, int fan, int speed)
 313 {
 314         struct smm_regs regs = { .eax = I8K_SMM_GET_NOM_SPEED, };
 315
 316         if (data->disallow_fan_support)
 317                 return -EINVAL;
 318
 319         regs.ebx = (fan & 0xff) | (speed << 8);
 320         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * data->i8k_fan_mult;
 321 }
 322
 323 /*
 324  * Enable or disable automatic BIOS fan control support
 325  */
 326 static int i8k_enable_fan_auto_mode(const struct dell_smm_data *data, bool enable)
 327 {
 328         struct smm_regs regs = { };
 329
 330         if (data->disallow_fan_support)
 331                 return -EINVAL;
 332
 333         regs.eax = enable ? data->auto_fan : data->manual_fan;
 334         return i8k_smm(&regs);
 335 }
 336
 337 /*
 338  * Set the fan speed (off, low, high). Returns the new fan status.
 339  */
 340 static int i8k_set_fan(const struct dell_smm_data *data, int fan, int speed)
 341 {
 342         struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
 343
 344         if (data->disallow_fan_support)
 345                 return -EINVAL;
 346
 347         speed = (speed < 0) ? 0 : ((speed > data->i8k_fan_max) ? data->i8k_fan_max : speed);
 348         regs.ebx = (fan & 0xff) | (speed << 8);
 349
 350         return i8k_smm(&regs) ? : i8k_get_fan_status(data, fan);
 351 }
 352
 353 static int __init i8k_get_temp_type(int sensor)
 354 {
 355         struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP_TYPE, };
 356
 357         regs.ebx = sensor & 0xff;
 358         return i8k_smm(&regs) ? : regs.eax & 0xff;
 359 }
 360
 361 /*
 362  * Read the cpu temperature.
 363  */
 364 static int _i8k_get_temp(int sensor)
 365 {
 366         struct smm_regs regs = {
 367                 .eax = I8K_SMM_GET_TEMP,
 368                 .ebx = sensor & 0xff,
 369         };
 370
 371         return i8k_smm(&regs) ? : regs.eax & 0xff;
 372 }
 373
 374 static int i8k_get_temp(int sensor)
 375 {
 376         int temp = _i8k_get_temp(sensor);
 377
 378         /*
 379          * Sometimes the temperature sensor returns 0x99, which is out of range.
 380          * In this case we retry (once) before returning an error.
 381          # 1003655137 00000058 00005a4b
 382          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 383          # 1003655139 00000054 00005c52
 384          */
 385         if (temp == 0x99) {
 386                 msleep(100);
 387                 temp = _i8k_get_temp(sensor);
 388         }
 389         /*
 390          * Return -ENODATA for all invalid temperatures.
 391          *
 392          * Known instances are the 0x99 value as seen above as well as
 393          * 0xc1 (193), which may be returned when trying to read the GPU
 394          * temperature if the system supports a GPU and it is currently
 395          * turned off.
 396          */
 397         if (temp > I8K_MAX_TEMP)
 398                 return -ENODATA;
 399
 400         return temp;
 401 }
 402
 403 static int __init i8k_get_dell_signature(int req_fn)
 404 {
 405         struct smm_regs regs = { .eax = req_fn, };
 406         int rc;
 407
 408         rc = i8k_smm(&regs);
 409         if (rc < 0)
 410                 return rc;
 411
 412         return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
 413 }
 414
 415 #if IS_ENABLED(CONFIG_I8K)
 416
 417 /*
 418  * Read the Fn key status.
 419  */
 420 static int i8k_get_fn_status(void)
 421 {
 422         struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
 423         int rc;
 424
 425         rc = i8k_smm(&regs);
 426         if (rc < 0)
 427                 return rc;
 428
 429         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 430         case I8K_FN_UP:
 431                 return I8K_VOL_UP;
 432         case I8K_FN_DOWN:
 433                 return I8K_VOL_DOWN;
 434         case I8K_FN_MUTE:
 435                 return I8K_VOL_MUTE;
 436         default:
 437                 return 0;
 438         }
 439 }
 440
 441 /*
 442  * Read the power status.
 443  */
 444 static int i8k_get_power_status(void)
 445 {
 446         struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
 447         int rc;
 448
 449         rc = i8k_smm(&regs);
 450         if (rc < 0)
 451                 return rc;
 452
 453         return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
 454 }
 455
 456 /*
 457  * Procfs interface
 458  */
 459
 460 static int
 461 i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned int cmd, unsigned long arg)
 462 {
 463         int val = 0;
 464         int speed;
 465         unsigned char buff[16];
 466         int __user *argp = (int __user *)arg;
 467
 468         if (!argp)
 469                 return -EINVAL;
 470
 471         switch (cmd) {
 472         case I8K_BIOS_VERSION:
 473                 if (!isdigit(data->bios_version[0]) || !isdigit(data->bios_version[1]) ||
 474                     !isdigit(data->bios_version[2]))
 475                         return -EINVAL;
 476
 477                 val = (data->bios_version[0] << 16) |
 478                                 (data->bios_version[1] << 8) | data->bios_version[2];
 479                 break;
 480
 481         case I8K_MACHINE_ID:
 482                 if (restricted && !capable(CAP_SYS_ADMIN))
 483                         return -EPERM;
 484
 485                 memset(buff, 0, sizeof(buff));
 486                 strscpy(buff, data->bios_machineid, sizeof(buff));
 487                 break;
 488
 489         case I8K_FN_STATUS:
 490                 val = i8k_get_fn_status();
 491                 break;
 492
 493         case I8K_POWER_STATUS:
 494                 val = i8k_get_power_status();
 495                 break;
 496
 497         case I8K_GET_TEMP:
 498                 val = i8k_get_temp(0);
 499                 break;
 500
 501         case I8K_GET_SPEED:
 502                 if (copy_from_user(&val, argp, sizeof(int)))
 503                         return -EFAULT;
 504
 505                 val = i8k_get_fan_speed(data, val);
 506                 break;
 507
 508         case I8K_GET_FAN:
 509                 if (copy_from_user(&val, argp, sizeof(int)))
 510                         return -EFAULT;
 511
 512                 val = i8k_get_fan_status(data, val);
 513                 break;
 514
 515         case I8K_SET_FAN:
 516                 if (restricted && !capable(CAP_SYS_ADMIN))
 517                         return -EPERM;
 518
 519                 if (copy_from_user(&val, argp, sizeof(int)))
 520                         return -EFAULT;
 521
 522                 if (copy_from_user(&speed, argp + 1, sizeof(int)))
 523                         return -EFAULT;
 524
 525                 val = i8k_set_fan(data, val, speed);
 526                 break;
 527
 528         default:
 529                 return -EINVAL;
 530         }
 531
 532         if (val < 0)
 533                 return val;
 534
 535         switch (cmd) {
 536         case I8K_BIOS_VERSION:
 537                 if (copy_to_user(argp, &val, 4))
 538                         return -EFAULT;
 539
 540                 break;
 541         case I8K_MACHINE_ID:
 542                 if (copy_to_user(argp, buff, 16))
 543                         return -EFAULT;
 544
 545                 break;
 546         default:
 547                 if (copy_to_user(argp, &val, sizeof(int)))
 548                         return -EFAULT;
 549
 550                 break;
 551         }
 552
 553         return 0;
 554 }
 555
 556 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 557 {
 558         struct dell_smm_data *data = PDE_DATA(file_inode(fp));
 559         long ret;
 560
 561         mutex_lock(&data->i8k_mutex);
 562         ret = i8k_ioctl_unlocked(fp, data, cmd, arg);
 563         mutex_unlock(&data->i8k_mutex);
 564
 565         return ret;
 566 }
 567
 568 /*
 569  * Print the information for /proc/i8k.
 570  */
 571 static int i8k_proc_show(struct seq_file *seq, void *offset)
 572 {
 573         struct dell_smm_data *data = seq->private;
 574         int fn_key, cpu_temp, ac_power;
 575         int left_fan, right_fan, left_speed, right_speed;
 576
 577         cpu_temp        = i8k_get_temp(0);                              /* 11100 µs */
 578         left_fan        = i8k_get_fan_status(data, I8K_FAN_LEFT);       /*   580 µs */
 579         right_fan       = i8k_get_fan_status(data, I8K_FAN_RIGHT);      /*   580 µs */
 580         left_speed      = i8k_get_fan_speed(data, I8K_FAN_LEFT);        /*   580 µs */
 581         right_speed     = i8k_get_fan_speed(data, I8K_FAN_RIGHT);       /*   580 µs */
 582         fn_key          = i8k_get_fn_status();                          /*   750 µs */
 583         if (power_status)
 584                 ac_power = i8k_get_power_status();                      /* 14700 µs */
 585         else
 586                 ac_power = -1;
 587
 588         /*
 589          * Info:
 590          *
 591          * 1)  Format version (this will change if format changes)
 592          * 2)  BIOS version
 593          * 3)  BIOS machine ID
 594          * 4)  Cpu temperature
 595          * 5)  Left fan status
 596          * 6)  Right fan status
 597          * 7)  Left fan speed
 598          * 8)  Right fan speed
 599          * 9)  AC power
 600          * 10) Fn Key status
 601          */
 602         seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 603                    I8K_PROC_FMT,
 604                    data->bios_version,
 605                    (restricted && !capable(CAP_SYS_ADMIN)) ? "-1" : data->bios_machineid,
 606                    cpu_temp,
 607                    left_fan, right_fan, left_speed, right_speed,
 608                    ac_power, fn_key);
 609
 610         return 0;
 611 }
 612
 613 static int i8k_open_fs(struct inode *inode, struct file *file)
 614 {
 615         return single_open(file, i8k_proc_show, PDE_DATA(inode));
 616 }
 617
 618 static const struct proc_ops i8k_proc_ops = {
 619         .proc_open      = i8k_open_fs,
 620         .proc_read      = seq_read,
 621         .proc_lseek     = seq_lseek,
 622         .proc_release   = single_release,
 623         .proc_ioctl     = i8k_ioctl,
 624 };
 625
 626 static void i8k_exit_procfs(void *param)
 627 {
 628         remove_proc_entry("i8k", NULL);
 629 }
 630
 631 static void __init i8k_init_procfs(struct device *dev)
 632 {
 633         struct dell_smm_data *data = dev_get_drvdata(dev);
 634
 635         /* Register the proc entry */
 636         proc_create_data("i8k", 0, NULL, &i8k_proc_ops, data);
 637
 638         devm_add_action_or_reset(dev, i8k_exit_procfs, NULL);
 639 }
 640
 641 #else
 642
 643 static void __init i8k_init_procfs(struct device *dev)
 644 {
 645 }
 646
 647 #endif
 648
 649 /*
 650  * Hwmon interface
 651  */
 652
 653 static umode_t dell_smm_is_visible(const void *drvdata, enum hwmon_sensor_types type, u32 attr,
 654                                    int channel)
 655 {
 656         const struct dell_smm_data *data = drvdata;
 657
 658         switch (type) {
 659         case hwmon_temp:
 660                 switch (attr) {
 661                 case hwmon_temp_input:
 662                 case hwmon_temp_label:
 663                         if (data->temp_type[channel] >= 0)
 664                                 return 0444;
 665
 666                         break;
 667                 default:
 668                         break;
 669                 }
 670                 break;
 671         case hwmon_fan:
 672                 if (data->disallow_fan_support)
 673                         break;
 674
 675                 switch (attr) {
 676                 case hwmon_fan_input:
 677                         if (data->fan[channel])
 678                                 return 0444;
 679
 680                         break;
 681                 case hwmon_fan_label:
 682                         if (data->fan[channel] && !data->disallow_fan_type_call)
 683                                 return 0444;
 684
 685                         break;
 686                 default:
 687                         break;
 688                 }
 689                 break;
 690         case hwmon_pwm:
 691                 if (data->disallow_fan_support)
 692                         break;
 693
 694                 switch (attr) {
 695                 case hwmon_pwm_input:
 696                         if (data->fan[channel])
 697                                 return 0644;
 698
 699                         break;
 700                 case hwmon_pwm_enable:
 701                         if (data->auto_fan)
 702                                 /*
 703                                  * There is no command for retrieve the current status
 704                                  * from BIOS, and userspace/firmware itself can change
 705                                  * it.
 706                                  * Thus we can only provide write-only access for now.
 707                                  */
 708                                 return 0200;
 709
 710                         break;
 711                 default:
 712                         break;
 713                 }
 714                 break;
 715         default:
 716                 break;
 717         }
 718
 719         return 0;
 720 }
 721
 722 static int dell_smm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
 723                          long *val)
 724 {
 725         struct dell_smm_data *data = dev_get_drvdata(dev);
 726         int ret;
 727
 728         switch (type) {
 729         case hwmon_temp:
 730                 switch (attr) {
 731                 case hwmon_temp_input:
 732                         ret = i8k_get_temp(channel);
 733                         if (ret < 0)
 734                                 return ret;
 735
 736                         *val = ret * 1000;
 737
 738                         return 0;
 739                 default:
 740                         break;
 741                 }
 742                 break;
 743         case hwmon_fan:
 744                 switch (attr) {
 745                 case hwmon_fan_input:
 746                         ret = i8k_get_fan_speed(data, channel);
 747                         if (ret < 0)
 748                                 return ret;
 749
 750                         *val = ret;
 751
 752                         return 0;
 753                 default:
 754                         break;
 755                 }
 756                 break;
 757         case hwmon_pwm:
 758                 switch (attr) {
 759                 case hwmon_pwm_input:
 760                         ret = i8k_get_fan_status(data, channel);
 761                         if (ret < 0)
 762                                 return ret;
 763
 764                         *val = clamp_val(ret * data->i8k_pwm_mult, 0, 255);
 765
 766                         return 0;
 767                 default:
 768                         break;
 769                 }
 770                 break;
 771         default:
 772                 break;
 773         }
 774
 775         return -EOPNOTSUPP;
 776 }
 777
 778 static const char *dell_smm_fan_label(struct dell_smm_data *data, int channel)
 779 {
 780         bool dock = false;
 781         int type = i8k_get_fan_type(data, channel);
 782
 783         if (type < 0)
 784                 return ERR_PTR(type);
 785
 786         if (type & 0x10) {
 787                 dock = true;
 788                 type &= 0x0F;
 789         }
 790
 791         if (type >= ARRAY_SIZE(fan_labels))
 792                 type = ARRAY_SIZE(fan_labels) - 1;
 793
 794         return dock ? docking_labels[type] : fan_labels[type];
 795 }
 796
 797 static int dell_smm_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 798                                 int channel, const char **str)
 799 {
 800         struct dell_smm_data *data = dev_get_drvdata(dev);
 801
 802         switch (type) {
 803         case hwmon_temp:
 804                 switch (attr) {
 805                 case hwmon_temp_label:
 806                         *str = temp_labels[data->temp_type[channel]];
 807                         return 0;
 808                 default:
 809                         break;
 810                 }
 811                 break;
 812         case hwmon_fan:
 813                 switch (attr) {
 814                 case hwmon_fan_label:
 815                         *str = dell_smm_fan_label(data, channel);
 816                         return PTR_ERR_OR_ZERO(*str);
 817                 default:
 818                         break;
 819                 }
 820                 break;
 821         default:
 822                 break;
 823         }
 824
 825         return -EOPNOTSUPP;
 826 }
 827
 828 static int dell_smm_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
 829                           long val)
 830 {
 831         struct dell_smm_data *data = dev_get_drvdata(dev);
 832         unsigned long pwm;
 833         bool enable;
 834         int err;
 835
 836         switch (type) {
 837         case hwmon_pwm:
 838                 switch (attr) {
 839                 case hwmon_pwm_input:
 840                         pwm = clamp_val(DIV_ROUND_CLOSEST(val, data->i8k_pwm_mult), 0,
 841                                         data->i8k_fan_max);
 842
 843                         mutex_lock(&data->i8k_mutex);
 844                         err = i8k_set_fan(data, channel, pwm);
 845                         mutex_unlock(&data->i8k_mutex);
 846
 847                         if (err < 0)
 848                                 return err;
 849
 850                         return 0;
 851                 case hwmon_pwm_enable:
 852                         if (!val)
 853                                 return -EINVAL;
 854
 855                         if (val == 1)
 856                                 enable = false;
 857                         else
 858                                 enable = true;
 859
 860                         mutex_lock(&data->i8k_mutex);
 861                         err = i8k_enable_fan_auto_mode(data, enable);
 862                         mutex_unlock(&data->i8k_mutex);
 863
 864                         if (err < 0)
 865                                 return err;
 866
 867                         return 0;
 868                 default:
 869                         break;
 870                 }
 871                 break;
 872         default:
 873                 break;
 874         }
 875
 876         return -EOPNOTSUPP;
 877 }
 878
 879 static const struct hwmon_ops dell_smm_ops = {
 880         .is_visible = dell_smm_is_visible,
 881         .read = dell_smm_read,
 882         .read_string = dell_smm_read_string,
 883         .write = dell_smm_write,
 884 };
 885
 886 static const struct hwmon_channel_info *dell_smm_info[] = {
 887         HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 888         HWMON_CHANNEL_INFO(temp,
 889                            HWMON_T_INPUT | HWMON_T_LABEL,
 890                            HWMON_T_INPUT | HWMON_T_LABEL,
 891                            HWMON_T_INPUT | HWMON_T_LABEL,
 892                            HWMON_T_INPUT | HWMON_T_LABEL,
 893                            HWMON_T_INPUT | HWMON_T_LABEL,
 894                            HWMON_T_INPUT | HWMON_T_LABEL,
 895                            HWMON_T_INPUT | HWMON_T_LABEL,
 896                            HWMON_T_INPUT | HWMON_T_LABEL,
 897                            HWMON_T_INPUT | HWMON_T_LABEL,
 898                            HWMON_T_INPUT | HWMON_T_LABEL
 899                            ),
 900         HWMON_CHANNEL_INFO(fan,
 901                            HWMON_F_INPUT | HWMON_F_LABEL,
 902                            HWMON_F_INPUT | HWMON_F_LABEL,
 903                            HWMON_F_INPUT | HWMON_F_LABEL
 904                            ),
 905         HWMON_CHANNEL_INFO(pwm,
 906                            HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
 907                            HWMON_PWM_INPUT,
 908                            HWMON_PWM_INPUT
 909                            ),
 910         NULL
 911 };
 912
 913 static const struct hwmon_chip_info dell_smm_chip_info = {
 914         .ops = &dell_smm_ops,
 915         .info = dell_smm_info,
 916 };
 917
 918 static int __init dell_smm_init_hwmon(struct device *dev)
 919 {
 920         struct dell_smm_data *data = dev_get_drvdata(dev);
 921         struct device *dell_smm_hwmon_dev;
 922         int i, err;
 923
 924         for (i = 0; i < DELL_SMM_NO_TEMP; i++) {
 925                 data->temp_type[i] = i8k_get_temp_type(i);
 926                 if (data->temp_type[i] < 0)
 927                         continue;
 928
 929                 if (data->temp_type[i] >= ARRAY_SIZE(temp_labels))
 930                         data->temp_type[i] = ARRAY_SIZE(temp_labels) - 1;
 931         }
 932
 933         for (i = 0; i < DELL_SMM_NO_FANS; i++) {
 934                 data->fan_type[i] = INT_MIN;
 935                 err = i8k_get_fan_status(data, i);
 936                 if (err < 0)
 937                         err = i8k_get_fan_type(data, i);
 938                 if (err >= 0)
 939                         data->fan[i] = true;
 940         }
 941
 942         dell_smm_hwmon_dev = devm_hwmon_device_register_with_info(dev, "dell_smm", data,
 943                                                                   &dell_smm_chip_info, NULL);
 944
 945         return PTR_ERR_OR_ZERO(dell_smm_hwmon_dev);
 946 }
 947
 948 struct i8k_config_data {
 949         uint fan_mult;
 950         uint fan_max;
 951 };
 952
 953 enum i8k_configs {
 954         DELL_LATITUDE_D520,
 955         DELL_PRECISION_490,
 956         DELL_STUDIO,
 957         DELL_XPS,
 958 };
 959
 960 static const struct i8k_config_data i8k_config_data[] = {
 961         [DELL_LATITUDE_D520] = {
 962                 .fan_mult = 1,
 963                 .fan_max = I8K_FAN_TURBO,
 964         },
 965         [DELL_PRECISION_490] = {
 966                 .fan_mult = 1,
 967                 .fan_max = I8K_FAN_TURBO,
 968         },
 969         [DELL_STUDIO] = {
 970                 .fan_mult = 1,
 971                 .fan_max = I8K_FAN_HIGH,
 972         },
 973         [DELL_XPS] = {
 974                 .fan_mult = 1,
 975                 .fan_max = I8K_FAN_HIGH,
 976         },
 977 };
 978
 979 static const struct dmi_system_id i8k_dmi_table[] __initconst = {
 980         {
 981                 .ident = "Dell Inspiron",
 982                 .matches = {
 983                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 984                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 985                 },
 986         },
 987         {
 988                 .ident = "Dell Latitude",
 989                 .matches = {
 990                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 991                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 992                 },
 993         },
 994         {
 995                 .ident = "Dell Inspiron 2",
 996                 .matches = {
 997                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 998                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 999                 },
1000         },
1001         {
1002                 .ident = "Dell Latitude D520",
1003                 .matches = {
1004                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1005                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
1006                 },
1007                 .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
1008         },
1009         {
1010                 .ident = "Dell Latitude 2",
1011                 .matches = {
1012                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1013                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
1014                 },
1015         },
1016         {       /* UK Inspiron 6400  */
1017                 .ident = "Dell Inspiron 3",
1018                 .matches = {
1019                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1020                         DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
1021                 },
1022         },
1023         {
1024                 .ident = "Dell Inspiron 3",
1025                 .matches = {
1026                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1027                         DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
1028                 },
1029         },
1030         {
1031                 .ident = "Dell Precision 490",
1032                 .matches = {
1033                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1034                         DMI_MATCH(DMI_PRODUCT_NAME,
1035                                   "Precision WorkStation 490"),
1036                 },
1037                 .driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
1038         },
1039         {
1040                 .ident = "Dell Precision",
1041                 .matches = {
1042                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1043                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
1044                 },
1045         },
1046         {
1047                 .ident = "Dell Vostro",
1048                 .matches = {
1049                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1050                         DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
1051                 },
1052         },
1053         {
1054                 .ident = "Dell Studio",
1055                 .matches = {
1056                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1057                         DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
1058                 },
1059                 .driver_data = (void *)&i8k_config_data[DELL_STUDIO],
1060         },
1061         {
1062                 .ident = "Dell XPS M140",
1063                 .matches = {
1064                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1065                         DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
1066                 },
1067                 .driver_data = (void *)&i8k_config_data[DELL_XPS],
1068         },
1069         {
1070                 .ident = "Dell XPS",
1071                 .matches = {
1072                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1073                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS"),
1074                 },
1075         },
1076         { }
1077 };
1078
1079 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
1080
1081 /*
1082  * On some machines once I8K_SMM_GET_FAN_TYPE is issued then CPU fan speed
1083  * randomly going up and down due to bug in Dell SMM or BIOS. Here is blacklist
1084  * of affected Dell machines for which we disallow I8K_SMM_GET_FAN_TYPE call.
1085  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=100121
1086  */
1087 static const struct dmi_system_id i8k_blacklist_fan_type_dmi_table[] __initconst = {
1088         {
1089                 .ident = "Dell Studio XPS 8000",
1090                 .matches = {
1091                         DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1092                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8000"),
1093                 },
1094         },
1095         {
1096                 .ident = "Dell Studio XPS 8100",
1097                 .matches = {
1098                         DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1099                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Studio XPS 8100"),
1100                 },
1101         },
1102         {
1103                 .ident = "Dell Inspiron 580",
1104                 .matches = {
1105                         DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1106                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 580 "),
1107                 },
1108         },
1109         { }
1110 };
1111
1112 /*
1113  * On some machines all fan related SMM functions implemented by Dell BIOS
1114  * firmware freeze kernel for about 500ms. Until Dell fixes these problems fan
1115  * support for affected blacklisted Dell machines stay disabled.
1116  * See bug: https://bugzilla.kernel.org/show_bug.cgi?id=195751
1117  */
1118 static struct dmi_system_id i8k_blacklist_fan_support_dmi_table[] __initdata = {
1119         {
1120                 .ident = "Dell Inspiron 7720",
1121                 .matches = {
1122                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1123                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
1124                 },
1125         },
1126         {
1127                 .ident = "Dell Vostro 3360",
1128                 .matches = {
1129                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1130                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
1131                 },
1132         },
1133         {
1134                 .ident = "Dell XPS13 9333",
1135                 .matches = {
1136                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1137                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
1138                 },
1139         },
1140         {
1141                 .ident = "Dell XPS 15 L502X",
1142                 .matches = {
1143                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1144                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Dell System XPS L502X"),
1145                 },
1146         },
1147         { }
1148 };
1149
1150 struct i8k_fan_control_data {
1151         unsigned int manual_fan;
1152         unsigned int auto_fan;
1153 };
1154
1155 enum i8k_fan_controls {
1156         I8K_FAN_34A3_35A3,
1157 };
1158
1159 static const struct i8k_fan_control_data i8k_fan_control_data[] = {
1160         [I8K_FAN_34A3_35A3] = {
1161                 .manual_fan = 0x34a3,
1162                 .auto_fan = 0x35a3,
1163         },
1164 };
1165
1166 static struct dmi_system_id i8k_whitelist_fan_control[] __initdata = {
1167         {
1168                 .ident = "Dell Latitude 5480",
1169                 .matches = {
1170                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1171                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude 5480"),
1172                 },
1173                 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1174         },
1175         {
1176                 .ident = "Dell Latitude E6440",
1177                 .matches = {
1178                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1179                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
1180                 },
1181                 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1182         },
1183         {
1184                 .ident = "Dell Latitude E7440",
1185                 .matches = {
1186                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1187                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Latitude E7440"),
1188                 },
1189                 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1190         },
1191         {
1192                 .ident = "Dell Precision 5530",
1193                 .matches = {
1194                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1195                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 5530"),
1196                 },
1197                 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1198         },
1199         {
1200                 .ident = "Dell Precision 7510",
1201                 .matches = {
1202                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
1203                         DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Precision 7510"),
1204                 },
1205                 .driver_data = (void *)&i8k_fan_control_data[I8K_FAN_34A3_35A3],
1206         },
1207         { }
1208 };
1209
1210 static int __init dell_smm_probe(struct platform_device *pdev)
1211 {
1212         struct dell_smm_data *data;
1213         const struct dmi_system_id *id, *fan_control;
1214         int fan, ret;
1215
1216         data = devm_kzalloc(&pdev->dev, sizeof(struct dell_smm_data), GFP_KERNEL);
1217         if (!data)
1218                 return -ENOMEM;
1219
1220         mutex_init(&data->i8k_mutex);
1221         data->i8k_fan_mult = I8K_FAN_MULT;
1222         data->i8k_fan_max = I8K_FAN_HIGH;
1223         platform_set_drvdata(pdev, data);
1224
1225         if (dmi_check_system(i8k_blacklist_fan_support_dmi_table)) {
1226                 dev_warn(&pdev->dev, "broken Dell BIOS detected, disallow fan support\n");
1227                 if (!force)
1228                         data->disallow_fan_support = true;
1229         }
1230
1231         if (dmi_check_system(i8k_blacklist_fan_type_dmi_table)) {
1232                 dev_warn(&pdev->dev, "broken Dell BIOS detected, disallow fan type call\n");
1233                 if (!force)
1234                         data->disallow_fan_type_call = true;
1235         }
1236
1237         strscpy(data->bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
1238                 sizeof(data->bios_version));
1239         strscpy(data->bios_machineid, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
1240                 sizeof(data->bios_machineid));
1241
1242         /*
1243          * Set fan multiplier and maximal fan speed from dmi config
1244          * Values specified in module parameters override values from dmi
1245          */
1246         id = dmi_first_match(i8k_dmi_table);
1247         if (id && id->driver_data) {
1248                 const struct i8k_config_data *conf = id->driver_data;
1249
1250                 if (!fan_mult && conf->fan_mult)
1251                         fan_mult = conf->fan_mult;
1252
1253                 if (!fan_max && conf->fan_max)
1254                         fan_max = conf->fan_max;
1255         }
1256
1257         data->i8k_fan_max = fan_max ? : I8K_FAN_HIGH;   /* Must not be 0 */
1258         data->i8k_pwm_mult = DIV_ROUND_UP(255, data->i8k_fan_max);
1259
1260         fan_control = dmi_first_match(i8k_whitelist_fan_control);
1261         if (fan_control && fan_control->driver_data) {
1262                 const struct i8k_fan_control_data *control = fan_control->driver_data;
1263
1264                 data->manual_fan = control->manual_fan;
1265                 data->auto_fan = control->auto_fan;
1266                 dev_info(&pdev->dev, "enabling support for setting automatic/manual fan control\n");
1267         }
1268
1269         if (!fan_mult) {
1270                 /*
1271                  * Autodetect fan multiplier based on nominal rpm
1272                  * If fan reports rpm value too high then set multiplier to 1
1273                  */
1274                 for (fan = 0; fan < DELL_SMM_NO_FANS; ++fan) {
1275                         ret = i8k_get_fan_nominal_speed(data, fan, data->i8k_fan_max);
1276                         if (ret < 0)
1277                                 continue;
1278
1279                         if (ret > I8K_FAN_MAX_RPM)
1280                                 data->i8k_fan_mult = 1;
1281                         break;
1282                 }
1283         } else {
1284                 /* Fan multiplier was specified in module param or in dmi */
1285                 data->i8k_fan_mult = fan_mult;
1286         }
1287
1288         ret = dell_smm_init_hwmon(&pdev->dev);
1289         if (ret)
1290                 return ret;
1291
1292         i8k_init_procfs(&pdev->dev);
1293
1294         return 0;
1295 }
1296
1297 static struct platform_driver dell_smm_driver = {
1298         .driver         = {
1299                 .name   = KBUILD_MODNAME,
1300         },
1301 };
1302
1303 static struct platform_device *dell_smm_device;
1304
1305 /*
1306  * Probe for the presence of a supported laptop.
1307  */
1308 static int __init i8k_init(void)
1309 {
1310         /*
1311          * Get DMI information
1312          */
1313         if (!dmi_check_system(i8k_dmi_table)) {
1314                 if (!ignore_dmi && !force)
1315                         return -ENODEV;
1316
1317                 pr_info("not running on a supported Dell system.\n");
1318                 pr_info("vendor=%s, model=%s, version=%s\n",
1319                         i8k_get_dmi_data(DMI_SYS_VENDOR),
1320                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
1321                         i8k_get_dmi_data(DMI_BIOS_VERSION));
1322         }
1323
1324         /*
1325          * Get SMM Dell signature
1326          */
1327         if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
1328             i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
1329                 pr_err("unable to get SMM Dell signature\n");
1330                 if (!force)
1331                         return -ENODEV;
1332         }
1333
1334         dell_smm_device = platform_create_bundle(&dell_smm_driver, dell_smm_probe, NULL, 0, NULL,
1335                                                  0);
1336
1337         return PTR_ERR_OR_ZERO(dell_smm_device);
1338 }
1339
1340 static void __exit i8k_exit(void)
1341 {
1342         platform_device_unregister(dell_smm_device);
1343         platform_driver_unregister(&dell_smm_driver);
1344 }
1345
1346 module_init(i8k_init);
1347 module_exit(i8k_exit);