drivers/char/i8k.c

   1 /*
   2  * i8k.c -- Linux driver for accessing the SMM BIOS on Dell laptops.
   3  *
   4  * Copyright (C) 2001  Massimo Dal Zotto <dz@debian.org>
   5  *
   6  * Hwmon integration:
   7  * Copyright (C) 2011  Jean Delvare <jdelvare@suse.de>
   8  * Copyright (C) 2013  Guenter Roeck <linux@roeck-us.net>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the
  12  * Free Software Foundation; either version 2, or (at your option) any
  13  * later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/init.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/dmi.h>
  29 #include <linux/capability.h>
  30 #include <linux/mutex.h>
  31 #include <linux/hwmon.h>
  32 #include <linux/hwmon-sysfs.h>
  33 #include <linux/uaccess.h>
  34 #include <linux/io.h>
  35 #include <linux/sched.h>
  36
  37 #include <linux/i8k.h>
  38
  39 #define I8K_SMM_FN_STATUS       0x0025
  40 #define I8K_SMM_POWER_STATUS    0x0069
  41 #define I8K_SMM_SET_FAN         0x01a3
  42 #define I8K_SMM_GET_FAN         0x00a3
  43 #define I8K_SMM_GET_SPEED       0x02a3
  44 #define I8K_SMM_GET_TEMP        0x10a3
  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_MAX_TEMP            127
  50
  51 #define I8K_FN_NONE             0x00
  52 #define I8K_FN_UP               0x01
  53 #define I8K_FN_DOWN             0x02
  54 #define I8K_FN_MUTE             0x04
  55 #define I8K_FN_MASK             0x07
  56 #define I8K_FN_SHIFT            8
  57
  58 #define I8K_POWER_AC            0x05
  59 #define I8K_POWER_BATTERY       0x01
  60
  61 #define I8K_TEMPERATURE_BUG     1
  62
  63 static DEFINE_MUTEX(i8k_mutex);
  64 static char bios_version[4];
  65 static struct device *i8k_hwmon_dev;
  66 static u32 i8k_hwmon_flags;
  67 static int i8k_fan_mult;
  68 static int i8k_pwm_mult;
  69 static int i8k_fan_max = I8K_FAN_HIGH;
  70
  71 #define I8K_HWMON_HAVE_TEMP1    (1 << 0)
  72 #define I8K_HWMON_HAVE_TEMP2    (1 << 1)
  73 #define I8K_HWMON_HAVE_TEMP3    (1 << 2)
  74 #define I8K_HWMON_HAVE_TEMP4    (1 << 3)
  75 #define I8K_HWMON_HAVE_FAN1     (1 << 4)
  76 #define I8K_HWMON_HAVE_FAN2     (1 << 5)
  77
  78 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
  79 MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
  80 MODULE_LICENSE("GPL");
  81
  82 static bool force;
  83 module_param(force, bool, 0);
  84 MODULE_PARM_DESC(force, "Force loading without checking for supported models");
  85
  86 static bool ignore_dmi;
  87 module_param(ignore_dmi, bool, 0);
  88 MODULE_PARM_DESC(ignore_dmi, "Continue probing hardware even if DMI data does not match");
  89
  90 static bool restricted;
  91 module_param(restricted, bool, 0);
  92 MODULE_PARM_DESC(restricted, "Allow fan control if SYS_ADMIN capability set");
  93
  94 static bool power_status;
  95 module_param(power_status, bool, 0600);
  96 MODULE_PARM_DESC(power_status, "Report power status in /proc/i8k");
  97
  98 static int fan_mult = I8K_FAN_MULT;
  99 module_param(fan_mult, int, 0);
 100 MODULE_PARM_DESC(fan_mult, "Factor to multiply fan speed with");
 101
 102 static int fan_max = I8K_FAN_HIGH;
 103 module_param(fan_max, int, 0);
 104 MODULE_PARM_DESC(fan_max, "Maximum configurable fan speed");
 105
 106 static int i8k_open_fs(struct inode *inode, struct file *file);
 107 static long i8k_ioctl(struct file *, unsigned int, unsigned long);
 108
 109 static const struct file_operations i8k_fops = {
 110         .owner          = THIS_MODULE,
 111         .open           = i8k_open_fs,
 112         .read           = seq_read,
 113         .llseek         = seq_lseek,
 114         .release        = single_release,
 115         .unlocked_ioctl = i8k_ioctl,
 116 };
 117
 118 struct 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
 127 static 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  */
 137 static int i8k_smm(struct smm_regs *regs)
 138 {
 139         int rc;
 140         int eax = regs->eax;
 141         cpumask_var_t old_mask;
 142
 143         /* SMM requires CPU 0 */
 144         if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
 145                 return -ENOMEM;
 146         cpumask_copy(old_mask, &current->cpus_allowed);
 147         rc = set_cpus_allowed_ptr(current, cpumask_of(0));
 148         if (rc)
 149                 goto out;
 150         if (smp_processor_id() != 0) {
 151                 rc = -EBUSY;
 152                 goto out;
 153         }
 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 out:
 212         set_cpus_allowed_ptr(current, old_mask);
 213         free_cpumask_var(old_mask);
 214         return rc;
 215 }
 216
 217 /*
 218  * Read the Fn key status.
 219  */
 220 static int i8k_get_fn_status(void)
 221 {
 222         struct smm_regs regs = { .eax = I8K_SMM_FN_STATUS, };
 223         int rc;
 224
 225         rc = i8k_smm(&regs);
 226         if (rc < 0)
 227                 return rc;
 228
 229         switch ((regs.eax >> I8K_FN_SHIFT) & I8K_FN_MASK) {
 230         case I8K_FN_UP:
 231                 return I8K_VOL_UP;
 232         case I8K_FN_DOWN:
 233                 return I8K_VOL_DOWN;
 234         case I8K_FN_MUTE:
 235                 return I8K_VOL_MUTE;
 236         default:
 237                 return 0;
 238         }
 239 }
 240
 241 /*
 242  * Read the power status.
 243  */
 244 static int i8k_get_power_status(void)
 245 {
 246         struct smm_regs regs = { .eax = I8K_SMM_POWER_STATUS, };
 247         int rc;
 248
 249         rc = i8k_smm(&regs);
 250         if (rc < 0)
 251                 return rc;
 252
 253         return (regs.eax & 0xff) == I8K_POWER_AC ? I8K_AC : I8K_BATTERY;
 254 }
 255
 256 /*
 257  * Read the fan status.
 258  */
 259 static int i8k_get_fan_status(int fan)
 260 {
 261         struct smm_regs regs = { .eax = I8K_SMM_GET_FAN, };
 262
 263         regs.ebx = fan & 0xff;
 264         return i8k_smm(&regs) ? : regs.eax & 0xff;
 265 }
 266
 267 /*
 268  * Read the fan speed in RPM.
 269  */
 270 static int i8k_get_fan_speed(int fan)
 271 {
 272         struct smm_regs regs = { .eax = I8K_SMM_GET_SPEED, };
 273
 274         regs.ebx = fan & 0xff;
 275         return i8k_smm(&regs) ? : (regs.eax & 0xffff) * i8k_fan_mult;
 276 }
 277
 278 /*
 279  * Set the fan speed (off, low, high). Returns the new fan status.
 280  */
 281 static int i8k_set_fan(int fan, int speed)
 282 {
 283         struct smm_regs regs = { .eax = I8K_SMM_SET_FAN, };
 284
 285         speed = (speed < 0) ? 0 : ((speed > i8k_fan_max) ? i8k_fan_max : speed);
 286         regs.ebx = (fan & 0xff) | (speed << 8);
 287
 288         return i8k_smm(&regs) ? : i8k_get_fan_status(fan);
 289 }
 290
 291 /*
 292  * Read the cpu temperature.
 293  */
 294 static int i8k_get_temp(int sensor)
 295 {
 296         struct smm_regs regs = { .eax = I8K_SMM_GET_TEMP, };
 297         int rc;
 298         int temp;
 299
 300 #ifdef I8K_TEMPERATURE_BUG
 301         static int prev[4] = { I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1, I8K_MAX_TEMP+1 };
 302 #endif
 303         regs.ebx = sensor & 0xff;
 304         rc = i8k_smm(&regs);
 305         if (rc < 0)
 306                 return rc;
 307
 308         temp = regs.eax & 0xff;
 309
 310 #ifdef I8K_TEMPERATURE_BUG
 311         /*
 312          * Sometimes the temperature sensor returns 0x99, which is out of range.
 313          * In this case we return (once) the previous cached value. For example:
 314          # 1003655137 00000058 00005a4b
 315          # 1003655138 00000099 00003a80 <--- 0x99 = 153 degrees
 316          # 1003655139 00000054 00005c52
 317          */
 318         if (temp > I8K_MAX_TEMP) {
 319                 temp = prev[sensor];
 320                 prev[sensor] = I8K_MAX_TEMP+1;
 321         } else {
 322                 prev[sensor] = temp;
 323         }
 324         if (temp > I8K_MAX_TEMP)
 325                 return -ERANGE;
 326 #endif
 327
 328         return temp;
 329 }
 330
 331 static int i8k_get_dell_signature(int req_fn)
 332 {
 333         struct smm_regs regs = { .eax = req_fn, };
 334         int rc;
 335
 336         rc = i8k_smm(&regs);
 337         if (rc < 0)
 338                 return rc;
 339
 340         return regs.eax == 1145651527 && regs.edx == 1145392204 ? 0 : -1;
 341 }
 342
 343 static int
 344 i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, unsigned long arg)
 345 {
 346         int val = 0;
 347         int speed;
 348         unsigned char buff[16];
 349         int __user *argp = (int __user *)arg;
 350
 351         if (!argp)
 352                 return -EINVAL;
 353
 354         switch (cmd) {
 355         case I8K_BIOS_VERSION:
 356                 val = (bios_version[0] << 16) |
 357                                 (bios_version[1] << 8) | bios_version[2];
 358                 break;
 359
 360         case I8K_MACHINE_ID:
 361                 memset(buff, 0, 16);
 362                 strlcpy(buff, i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
 363                         sizeof(buff));
 364                 break;
 365
 366         case I8K_FN_STATUS:
 367                 val = i8k_get_fn_status();
 368                 break;
 369
 370         case I8K_POWER_STATUS:
 371                 val = i8k_get_power_status();
 372                 break;
 373
 374         case I8K_GET_TEMP:
 375                 val = i8k_get_temp(0);
 376                 break;
 377
 378         case I8K_GET_SPEED:
 379                 if (copy_from_user(&val, argp, sizeof(int)))
 380                         return -EFAULT;
 381
 382                 val = i8k_get_fan_speed(val);
 383                 break;
 384
 385         case I8K_GET_FAN:
 386                 if (copy_from_user(&val, argp, sizeof(int)))
 387                         return -EFAULT;
 388
 389                 val = i8k_get_fan_status(val);
 390                 break;
 391
 392         case I8K_SET_FAN:
 393                 if (restricted && !capable(CAP_SYS_ADMIN))
 394                         return -EPERM;
 395
 396                 if (copy_from_user(&val, argp, sizeof(int)))
 397                         return -EFAULT;
 398
 399                 if (copy_from_user(&speed, argp + 1, sizeof(int)))
 400                         return -EFAULT;
 401
 402                 val = i8k_set_fan(val, speed);
 403                 break;
 404
 405         default:
 406                 return -EINVAL;
 407         }
 408
 409         if (val < 0)
 410                 return val;
 411
 412         switch (cmd) {
 413         case I8K_BIOS_VERSION:
 414                 if (copy_to_user(argp, &val, 4))
 415                         return -EFAULT;
 416
 417                 break;
 418         case I8K_MACHINE_ID:
 419                 if (copy_to_user(argp, buff, 16))
 420                         return -EFAULT;
 421
 422                 break;
 423         default:
 424                 if (copy_to_user(argp, &val, sizeof(int)))
 425                         return -EFAULT;
 426
 427                 break;
 428         }
 429
 430         return 0;
 431 }
 432
 433 static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long arg)
 434 {
 435         long ret;
 436
 437         mutex_lock(&i8k_mutex);
 438         ret = i8k_ioctl_unlocked(fp, cmd, arg);
 439         mutex_unlock(&i8k_mutex);
 440
 441         return ret;
 442 }
 443
 444 /*
 445  * Print the information for /proc/i8k.
 446  */
 447 static int i8k_proc_show(struct seq_file *seq, void *offset)
 448 {
 449         int fn_key, cpu_temp, ac_power;
 450         int left_fan, right_fan, left_speed, right_speed;
 451
 452         cpu_temp        = i8k_get_temp(0);                      /* 11100 µs */
 453         left_fan        = i8k_get_fan_status(I8K_FAN_LEFT);     /*   580 µs */
 454         right_fan       = i8k_get_fan_status(I8K_FAN_RIGHT);    /*   580 µs */
 455         left_speed      = i8k_get_fan_speed(I8K_FAN_LEFT);      /*   580 µs */
 456         right_speed     = i8k_get_fan_speed(I8K_FAN_RIGHT);     /*   580 µs */
 457         fn_key          = i8k_get_fn_status();                  /*   750 µs */
 458         if (power_status)
 459                 ac_power = i8k_get_power_status();              /* 14700 µs */
 460         else
 461                 ac_power = -1;
 462
 463         /*
 464          * Info:
 465          *
 466          * 1)  Format version (this will change if format changes)
 467          * 2)  BIOS version
 468          * 3)  BIOS machine ID
 469          * 4)  Cpu temperature
 470          * 5)  Left fan status
 471          * 6)  Right fan status
 472          * 7)  Left fan speed
 473          * 8)  Right fan speed
 474          * 9)  AC power
 475          * 10) Fn Key status
 476          */
 477         return seq_printf(seq, "%s %s %s %d %d %d %d %d %d %d\n",
 478                           I8K_PROC_FMT,
 479                           bios_version,
 480                           i8k_get_dmi_data(DMI_PRODUCT_SERIAL),
 481                           cpu_temp,
 482                           left_fan, right_fan, left_speed, right_speed,
 483                           ac_power, fn_key);
 484 }
 485
 486 static int i8k_open_fs(struct inode *inode, struct file *file)
 487 {
 488         return single_open(file, i8k_proc_show, NULL);
 489 }
 490
 491
 492 /*
 493  * Hwmon interface
 494  */
 495
 496 static ssize_t i8k_hwmon_show_temp(struct device *dev,
 497                                    struct device_attribute *devattr,
 498                                    char *buf)
 499 {
 500         int index = to_sensor_dev_attr(devattr)->index;
 501         int temp;
 502
 503         temp = i8k_get_temp(index);
 504         if (temp == -ERANGE)
 505                 return -EINVAL;
 506         if (temp < 0)
 507                 return temp;
 508         return sprintf(buf, "%d\n", temp * 1000);
 509 }
 510
 511 static ssize_t i8k_hwmon_show_fan(struct device *dev,
 512                                   struct device_attribute *devattr,
 513                                   char *buf)
 514 {
 515         int index = to_sensor_dev_attr(devattr)->index;
 516         int fan_speed;
 517
 518         fan_speed = i8k_get_fan_speed(index);
 519         if (fan_speed < 0)
 520                 return fan_speed;
 521         return sprintf(buf, "%d\n", fan_speed);
 522 }
 523
 524 static ssize_t i8k_hwmon_show_pwm(struct device *dev,
 525                                   struct device_attribute *devattr,
 526                                   char *buf)
 527 {
 528         int index = to_sensor_dev_attr(devattr)->index;
 529         int status;
 530
 531         status = i8k_get_fan_status(index);
 532         if (status < 0)
 533                 return -EIO;
 534         return sprintf(buf, "%d\n", clamp_val(status * i8k_pwm_mult, 0, 255));
 535 }
 536
 537 static ssize_t i8k_hwmon_set_pwm(struct device *dev,
 538                                  struct device_attribute *attr,
 539                                  const char *buf, size_t count)
 540 {
 541         int index = to_sensor_dev_attr(attr)->index;
 542         unsigned long val;
 543         int err;
 544
 545         err = kstrtoul(buf, 10, &val);
 546         if (err)
 547                 return err;
 548         val = clamp_val(DIV_ROUND_CLOSEST(val, i8k_pwm_mult), 0, i8k_fan_max);
 549
 550         mutex_lock(&i8k_mutex);
 551         err = i8k_set_fan(index, val);
 552         mutex_unlock(&i8k_mutex);
 553
 554         return err < 0 ? -EIO : count;
 555 }
 556
 557 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 0);
 558 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 1);
 559 static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
 560 static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
 561 static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
 562                           I8K_FAN_LEFT);
 563 static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
 564                           i8k_hwmon_set_pwm, I8K_FAN_LEFT);
 565 static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
 566                           I8K_FAN_RIGHT);
 567 static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
 568                           i8k_hwmon_set_pwm, I8K_FAN_RIGHT);
 569
 570 static struct attribute *i8k_attrs[] = {
 571         &sensor_dev_attr_temp1_input.dev_attr.attr,     /* 0 */
 572         &sensor_dev_attr_temp2_input.dev_attr.attr,     /* 1 */
 573         &sensor_dev_attr_temp3_input.dev_attr.attr,     /* 2 */
 574         &sensor_dev_attr_temp4_input.dev_attr.attr,     /* 3 */
 575         &sensor_dev_attr_fan1_input.dev_attr.attr,      /* 4 */
 576         &sensor_dev_attr_pwm1.dev_attr.attr,            /* 5 */
 577         &sensor_dev_attr_fan2_input.dev_attr.attr,      /* 6 */
 578         &sensor_dev_attr_pwm2.dev_attr.attr,            /* 7 */
 579         NULL
 580 };
 581
 582 static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
 583                               int index)
 584 {
 585         if (index == 0 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
 586                 return 0;
 587         if (index == 1 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP2))
 588                 return 0;
 589         if (index == 2 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP3))
 590                 return 0;
 591         if (index == 3 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
 592                 return 0;
 593         if (index >= 4 && index <= 5 &&
 594             !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
 595                 return 0;
 596         if (index >= 6 && index <= 7 &&
 597             !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
 598                 return 0;
 599
 600         return attr->mode;
 601 }
 602
 603 static const struct attribute_group i8k_group = {
 604         .attrs = i8k_attrs,
 605         .is_visible = i8k_is_visible,
 606 };
 607 __ATTRIBUTE_GROUPS(i8k);
 608
 609 static int __init i8k_init_hwmon(void)
 610 {
 611         int err;
 612
 613         i8k_hwmon_flags = 0;
 614
 615         /* CPU temperature attributes, if temperature reading is OK */
 616         err = i8k_get_temp(0);
 617         if (err >= 0 || err == -ERANGE)
 618                 i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;
 619         /* check for additional temperature sensors */
 620         err = i8k_get_temp(1);
 621         if (err >= 0 || err == -ERANGE)
 622                 i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP2;
 623         err = i8k_get_temp(2);
 624         if (err >= 0 || err == -ERANGE)
 625                 i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP3;
 626         err = i8k_get_temp(3);
 627         if (err >= 0 || err == -ERANGE)
 628                 i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
 629
 630         /* Left fan attributes, if left fan is present */
 631         err = i8k_get_fan_status(I8K_FAN_LEFT);
 632         if (err >= 0)
 633                 i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
 634
 635         /* Right fan attributes, if right fan is present */
 636         err = i8k_get_fan_status(I8K_FAN_RIGHT);
 637         if (err >= 0)
 638                 i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;
 639
 640         i8k_hwmon_dev = hwmon_device_register_with_groups(NULL, "i8k", NULL,
 641                                                           i8k_groups);
 642         if (IS_ERR(i8k_hwmon_dev)) {
 643                 err = PTR_ERR(i8k_hwmon_dev);
 644                 i8k_hwmon_dev = NULL;
 645                 pr_err("hwmon registration failed (%d)\n", err);
 646                 return err;
 647         }
 648         return 0;
 649 }
 650
 651 struct i8k_config_data {
 652         int fan_mult;
 653         int fan_max;
 654 };
 655
 656 enum i8k_configs {
 657         DELL_LATITUDE_D520,
 658         DELL_LATITUDE_E6540,
 659         DELL_PRECISION_490,
 660         DELL_STUDIO,
 661         DELL_XPS_M140,
 662 };
 663
 664 static const struct i8k_config_data i8k_config_data[] = {
 665         [DELL_LATITUDE_D520] = {
 666                 .fan_mult = 1,
 667                 .fan_max = I8K_FAN_TURBO,
 668         },
 669         [DELL_LATITUDE_E6540] = {
 670                 .fan_mult = 1,
 671                 .fan_max = I8K_FAN_HIGH,
 672         },
 673         [DELL_PRECISION_490] = {
 674                 .fan_mult = 1,
 675                 .fan_max = I8K_FAN_TURBO,
 676         },
 677         [DELL_STUDIO] = {
 678                 .fan_mult = 1,
 679                 .fan_max = I8K_FAN_HIGH,
 680         },
 681         [DELL_XPS_M140] = {
 682                 .fan_mult = 1,
 683                 .fan_max = I8K_FAN_HIGH,
 684         },
 685 };
 686
 687 static struct dmi_system_id i8k_dmi_table[] __initdata = {
 688         {
 689                 .ident = "Dell Inspiron",
 690                 .matches = {
 691                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 692                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 693                 },
 694         },
 695         {
 696                 .ident = "Dell Latitude",
 697                 .matches = {
 698                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer"),
 699                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 700                 },
 701         },
 702         {
 703                 .ident = "Dell Inspiron 2",
 704                 .matches = {
 705                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 706                         DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron"),
 707                 },
 708         },
 709         {
 710                 .ident = "Dell Latitude D520",
 711                 .matches = {
 712                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 713                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude D520"),
 714                 },
 715                 .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_D520],
 716         },
 717         {
 718                 .ident = "Dell Latitude E6440",
 719                 .matches = {
 720                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 721                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6440"),
 722                 },
 723                 .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_E6540],
 724         },
 725         {
 726                 .ident = "Dell Latitude E6540",
 727                 .matches = {
 728                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 729                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6540"),
 730                 },
 731                 .driver_data = (void *)&i8k_config_data[DELL_LATITUDE_E6540],
 732         },
 733         {
 734                 .ident = "Dell Latitude 2",
 735                 .matches = {
 736                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 737                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude"),
 738                 },
 739         },
 740         {       /* UK Inspiron 6400  */
 741                 .ident = "Dell Inspiron 3",
 742                 .matches = {
 743                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 744                         DMI_MATCH(DMI_PRODUCT_NAME, "MM061"),
 745                 },
 746         },
 747         {
 748                 .ident = "Dell Inspiron 3",
 749                 .matches = {
 750                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 751                         DMI_MATCH(DMI_PRODUCT_NAME, "MP061"),
 752                 },
 753         },
 754         {
 755                 .ident = "Dell Precision 490",
 756                 .matches = {
 757                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 758                         DMI_MATCH(DMI_PRODUCT_NAME,
 759                                   "Precision WorkStation 490"),
 760                 },
 761                 .driver_data = (void *)&i8k_config_data[DELL_PRECISION_490],
 762         },
 763         {
 764                 .ident = "Dell Precision",
 765                 .matches = {
 766                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 767                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision"),
 768                 },
 769         },
 770         {
 771                 .ident = "Dell Vostro",
 772                 .matches = {
 773                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 774                         DMI_MATCH(DMI_PRODUCT_NAME, "Vostro"),
 775                 },
 776         },
 777         {
 778                 .ident = "Dell XPS421",
 779                 .matches = {
 780                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 781                         DMI_MATCH(DMI_PRODUCT_NAME, "XPS L421X"),
 782                 },
 783         },
 784         {
 785                 .ident = "Dell Studio",
 786                 .matches = {
 787                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 788                         DMI_MATCH(DMI_PRODUCT_NAME, "Studio"),
 789                 },
 790                 .driver_data = (void *)&i8k_config_data[DELL_STUDIO],
 791         },
 792         {
 793                 .ident = "Dell XPS M140",
 794                 .matches = {
 795                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 796                         DMI_MATCH(DMI_PRODUCT_NAME, "MXC051"),
 797                 },
 798                 .driver_data = (void *)&i8k_config_data[DELL_XPS_M140],
 799         },
 800         { }
 801 };
 802
 803 MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
 804
 805 /*
 806  * Probe for the presence of a supported laptop.
 807  */
 808 static int __init i8k_probe(void)
 809 {
 810         const struct dmi_system_id *id;
 811
 812         /*
 813          * Get DMI information
 814          */
 815         if (!dmi_check_system(i8k_dmi_table)) {
 816                 if (!ignore_dmi && !force)
 817                         return -ENODEV;
 818
 819                 pr_info("not running on a supported Dell system.\n");
 820                 pr_info("vendor=%s, model=%s, version=%s\n",
 821                         i8k_get_dmi_data(DMI_SYS_VENDOR),
 822                         i8k_get_dmi_data(DMI_PRODUCT_NAME),
 823                         i8k_get_dmi_data(DMI_BIOS_VERSION));
 824         }
 825
 826         strlcpy(bios_version, i8k_get_dmi_data(DMI_BIOS_VERSION),
 827                 sizeof(bios_version));
 828
 829         /*
 830          * Get SMM Dell signature
 831          */
 832         if (i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG1) &&
 833             i8k_get_dell_signature(I8K_SMM_GET_DELL_SIG2)) {
 834                 pr_err("unable to get SMM Dell signature\n");
 835                 if (!force)
 836                         return -ENODEV;
 837         }
 838
 839         i8k_fan_mult = fan_mult;
 840         i8k_fan_max = fan_max ? : I8K_FAN_HIGH; /* Must not be 0 */
 841         id = dmi_first_match(i8k_dmi_table);
 842         if (id && id->driver_data) {
 843                 const struct i8k_config_data *conf = id->driver_data;
 844
 845                 if (fan_mult == I8K_FAN_MULT && conf->fan_mult)
 846                         i8k_fan_mult = conf->fan_mult;
 847                 if (fan_max == I8K_FAN_HIGH && conf->fan_max)
 848                         i8k_fan_max = conf->fan_max;
 849         }
 850         i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
 851
 852         return 0;
 853 }
 854
 855 static int __init i8k_init(void)
 856 {
 857         struct proc_dir_entry *proc_i8k;
 858         int err;
 859
 860         /* Are we running on an supported laptop? */
 861         if (i8k_probe())
 862                 return -ENODEV;
 863
 864         /* Register the proc entry */
 865         proc_i8k = proc_create("i8k", 0, NULL, &i8k_fops);
 866         if (!proc_i8k)
 867                 return -ENOENT;
 868
 869         err = i8k_init_hwmon();
 870         if (err)
 871                 goto exit_remove_proc;
 872
 873         return 0;
 874
 875  exit_remove_proc:
 876         remove_proc_entry("i8k", NULL);
 877         return err;
 878 }
 879
 880 static void __exit i8k_exit(void)
 881 {
 882         hwmon_device_unregister(i8k_hwmon_dev);
 883         remove_proc_entry("i8k", NULL);
 884 }
 885
 886 module_init(i8k_init);
 887 module_exit(i8k_exit);