Symlink a kernel device in nixos

Help
1

I recently bought a Thinkpad X1 Carbon Gen 6. I would like to use the special keys (Function keys) to adjust the Screen brightness and Keyboard backlight. I am able to do that via command line by following the instructions in the links.

However my nixos configuration seems unable to find those, even though I have these enabled:

programs.light.enable = true;
programs.kbdlight.enable = true;
hardware.acpilight.enable = true;

I found in the referenced links two approaches to make that work: one is to symlink the vendor devices to more general paths; the other is to add Xorg devices and control them from the graphical interface. However I fail to find in the Nixos manual how could I achieve that.

Thoughts?

Also, suggestions on enabling other Thinkpad stuff would be greatly appreciated. I also have

  imports =
    [
      <nixos-hardware/lenovo/thinkpad/x1/6th-gen>
      # Include the results of the hardware scan.
      /etc/nixos/hardware-configuration.nix
  ];

  services.thinkfan = {
    # postconditions:
    # 1) status should be enabled:
    # cat /proc/acpi/ibm/fan
    # 2) No errors in systemd logs:
    # journalctl -u thinkfan.service -f

    enable = true;
    sensors = ''
      # Entries here discovered by:
      # find /sys/devices -type f -name "temp*_input"
      hwmon /sys/devices/platform/coretemp.0/hwmon/hwmon3/temp3_input
      hwmon /sys/devices/platform/coretemp.0/hwmon/hwmon3/temp4_input
      hwmon /sys/devices/platform/coretemp.0/hwmon/hwmon3/temp1_input
      hwmon /sys/devices/platform/coretemp.0/hwmon/hwmon3/temp5_input
      hwmon /sys/devices/platform/coretemp.0/hwmon/hwmon3/temp2_input
      hwmon /sys/devices/virtual/thermal/thermal_zone2/hwmon1/temp1_input
      hwmon /sys/devices/virtual/thermal/thermal_zone6/hwmon4/temp1_input
      hwmon /sys/devices/virtual/thermal/thermal_zone4/hwmon2/temp1_input
    '';

    levels = ''
    (0,     0,      42)
    (1,     40,     47)
    (2,     45,     52)
    (3,     50,     57)
    (4,     55,     62)
    (5,     60,     77)
    (7,     73,     93)
    (127,   85,     32767)
    '';

    smartSupport = true;
  };

]

although the smartSupport is just a guess.

2

Thanks for services.thinkfan !