anchor.diff:          type = types.bool;
           default = false;
           description = ''
  -          Whether to enable thinkfan, fan controller for IBM/Lenovo ThinkPads.
  -        '';
  +          Whether to enable thinkfan, a fan control program.
  +
  +          <note><para>
  +            This module targets IBM/Lenovo thinkpads by default, for
  +            other hardware you will have configure it more carefully.
  +          </para></note>
  +        '';
  +        relatedPackages = [ "thinkfan" ];
         };
   
         smartSupport = mkOption {
           type = types.bool;
           default = false;
           description = ''
  -          Whether to build thinkfan with SMART support to read temperatures
  +          Whether to build thinkfan with S.M.A.R.T. support to read temperatures
             directly from hard disks.
           '';
         };
   
         sensors = mkOption {
  -        type = types.lines;
  -        default = ''
  -          tp_thermal /proc/acpi/ibm/thermal (0,0,10)
  -        '';
  -        description =''
  -          thinkfan can read temperatures from three possible sources:
  -
  -            /proc/acpi/ibm/thermal
  -              Which is provided by the thinkpad_acpi kernel
  -              module (keyword tp_thermal)
  -
  -            /sys/class/hwmon/*/temp*_input
  -              Which may be provided by any hwmon drivers (keyword
  -              hwmon)
  -
  -            S.M.A.R.T. (requires smartSupport to be enabled)
  -              Which reads the temperature directly from the hard
  -              disk using libatasmart (keyword atasmart)
  -
  -          Multiple sensors may be added, in which case they will be
  -          numbered in their order of appearance.
  -        '';
  -      };
  -
  -      fan = mkOption {
  -        type = types.str;
  -        default = "tp_fan /proc/acpi/ibm/fan";
  -        description =''
  -          Specifies the fan we want to use.
  -          On anything other than a Thinkpad you'll probably
  -          use some PWM control file in /sys/class/hwmon.
  -          A sysfs fan would be specified like this:
  -            pwm_fan /sys/class/hwmon/hwmon2/device/pwm1
  -        '';
  +        type = types.listOf (sensorType "sensor");
  +        default = [
  +          { type = "tpacpi";
  +            query = "/proc/acpi/ibm/thermal";
  +          }
  +        ];
  +        description = ''
  +          List of temperature sensors thinkfan will monitor.
  +        '' + syntaxNote "thermal";
  +      };
  +
  +      fans = mkOption {
  +        type = types.listOf (sensorType "fan");
  +        default = [
  +          { type = "tpacpi";
  +            query = "/proc/acpi/ibm/fan";
  +          }
  +        ];
  +        description = ''
  +          List of fans thinkfan will control.
  +        '' + syntaxNote "fan";
         };
   
         levels = mkOption {
  -        type = types.lines;
  -        default = ''
  -          (0,     0,      55)
  -          (1,     48,     60)
  -          (2,     50,     61)
  -          (3,     52,     63)
  -          (6,     56,     65)
  -          (7,     60,     85)
  -          (127,   80,     32767)
  -        '';
  -        description = ''
  -          (LEVEL, LOW, HIGH)
  -          LEVEL is the fan level to use (0-7 with thinkpad_acpi).
  +        type = types.listOf levelType;
  +        default = [
  +          [0  0   55]
  +          [1  48  60]
  +          [2  50  61]
  +          [3  52  63]
  +          [6  56  65]
  +          [7  60  85]
  +          ["level auto" 80 32767]
  +        ];
  +        description = ''
  +          [LEVEL LOW HIGH]
  +
  +          LEVEL is the fan level to use: it can be an integer (0-7 with thinkpad_acpi),
  +          "level auto" (to keep the default firmware behavior), "level full-speed" or
  +          "level disengage" (to run the fan as fast as possible).
             LOW is the temperature at which to step down to the previous level.
             HIGH is the temperature at which to step up to the next level.
             All numbers are integers.
           '';
         };
   
  +      extraArgs = mkOption {
  +        type = types.listOf types.str;
  +        default = [ ];
  +        example = [ "-b" "0" ];
  +        description = ''
  +          A list of extra command line arguments to pass to thinkfan.
  +          Check the thinkfan(1) manpage for available arguments.
  +        '';
  +      };
  +
  +      settings = mkOption {
  +        type = types.attrsOf settingsFormat.type;
  +        default = { };
  +        description = ''
  +          Thinkfan settings. Use this option to configure thinkfan
  +          settings not exposed in a NixOS option or to bypass one.
  +          Before changing this, read the <literal>thinkfan.conf(5)</literal>
  +          manpage and take a look at the example config file at
  +          <link xlink:href="https://github.com/vmatare/thinkfan/blob/master/examples/thinkfan.yaml"/>
  +        '';
  +      };
   
       };
   
  
positive.code: let
  
    cfg = config.services.thinkfan;
    configFile = pkgs.writeText "thinkfan.conf" ''
      # ATTENTION: There is only very basic sanity checking on the configuration.
      # That means you can set your temperature limits as insane as you like. You
      # can do anything stupid, e.g. turn off your fan when your CPU reaches 70°C.
      #
      # That's why this program is called THINKfan: You gotta think for yourself.
      #
      ######################################################################
      #
      # IBM/Lenovo Thinkpads (thinkpad_acpi, /proc/acpi/ibm)
      # ====================================================
      #
      # IMPORTANT:
      #
      # To keep your HD from overheating, you have to specify a correction value for
      # the sensor that has the HD's temperature. You need to do this because
      # thinkfan uses only the highest temperature it can find in the system, and
      # that'll most likely never be your HD, as most HDs are already out of spec
      # when they reach 55 °C.
      # Correction values are applied from left to right in the same order as the
      # temperatures are read from the file.
      #
      # For example:
      # tp_thermal /proc/acpi/ibm/thermal (0, 0, 10)
      # will add a fixed value of 10 °C the 3rd value read from that file. Check out
      # http://www.thinkwiki.org/wiki/Thermal_Sensors to find out how much you may
      # want to add to certain temperatures.
  
      ${cfg.fan}
      ${cfg.sensors}
  
      #  Syntax:
      #  (LEVEL, LOW, HIGH)
      #  LEVEL is the fan level to use (0-7 with thinkpad_acpi)
      #  LOW is the temperature at which to step down to the previous level
      #  HIGH is the temperature at which to step up to the next level
      #  All numbers are integers.
      #
  
      ${cfg.levels}
    '';
  
    thinkfan = pkgs.thinkfan.override { smartSupport = cfg.smartSupport; };
  
  in {
  
  
negative.code: 
      environment.systemPackages = [ thinkfan ];
  
      services.thinkfan.settings = mapAttrs (k: v: mkDefault v) {
        sensors = map sensorToConf cfg.sensors;
        fans    = map sensorToConf cfg.fans;
        levels  = cfg.levels;
      };
  
      systemd.packages = [ thinkfan ];
  
      systemd.services = {
        thinkfan.environment.THINKFAN_ARGS = escapeShellArgs ([ "-c" configFile ] ++ cfg.extraArgs);
  
        # must be added manually, see issue #81138
        thinkfan.wantedBy = [ "multi-user.target" ];
        thinkfan-wakeup.wantedBy = [ "sleep.target" ];
        thinkfan-sleep.wantedBy = [ "sleep.target" ];
      };
  
      boot.extraModprobeConfig = "options thinkpad_acpi experimental=1 fan_control=1";
  