NixOS on raspberry pi zero w

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Thank you very much for that tip. That did the trick in combination with my initial device tree overlay. I2C now works.

I then tried to analyze if I can get the &i2c1 version to work. Reading about your two links I now understand that these &[node] things are semantic sugar to extend other nodes. I then tried to use that in combination with the hardware.i2c.enable = true but I still had no success as I already predicted since this doesn’t change the dtb file (I already analyzed this in my last post). I then tried to remove the -i2c suffix and still had the hardware.i2c.enable = true set which works now. So

I2C TL;DR

To enable i2c on a raspberry pi zero, use:

          hardware.deviceTree = {
            enable = true;
            overlays = [
              {
                name = "enable-i2c1-device";
                dtsText = ''
                  /dts-v1/;
                  /plugin/;
                  / { compatible = "brcm,bcm2835"; };
                  &i2c1 { status = "okay"; };
                '';
              }
            ];
          };
          hardware.i2c.enable = true;

WIFI

I now also wifi to work by either

wpa_supplicant:

          hardware.firmware = [ pkgs.raspberrypiWirelessFirmware ];
          networking = {
            wireless = {
              enable = true;

              networks = {
                [SSID] = {
                  psk = "[PSK]";
                };
              };
            };
          };

or using iwd:

          systemd.services.iwd.serviceConfig.Restart = "always";
          hardware.firmware = [ pkgs.raspberrypiWirelessFirmware ];
          networking = {
            networkmanager.wifi.backend = "iwd";
            wireless.iwd.enable = true;
          };
          boot.extraModprobeConfig = ''
            options cfg80211 ieee80211_regdom="DE"
          '';

And then connect to the wifi using the following commands:

$ iwctl
# list
# station wlan0 scan
# station wlan0 get-networks
# station wlan0 connect [ssid]

This will save the config for the next boot to: /var/lib/iwd.

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