Enabled i2c bus

Author: DocBrown101

README.md

@@ -38,6 +38,7 @@ nix run github:serokell/deploy-rs .#zero2w -- --ssh-user $SSH_USER --hostname $Z
   - Note that `nixos-rebuild --target-host` would work instead of using `deploy-rs`. but as `nixos-rebuild` is not available on Darwin, I'm using `deploy-rs` that works both on NixOS and Darwin.
 - I still couldn't find a way to use `boot.kernelPackages = pkgs.linuxKernel.packages.linux_rpi3`. 
 - the `sdImage.extraFirmwareConfig` option is not ideal as it cannot update `config.txt` after it is created in the sd image.
+- An overlay in the `hardware.deviceTree` has activated the i2c bus. This means that the `i2c-tools` are now working!
 
 ## See also
 - [this issue](https://github.com/NixOS/nixpkgs/issues/216886)

zero2w.nix

@@ -45,9 +45,30 @@
     };
   };
 
-  # Keep this to make sure wifi works
-  hardware.enableRedistributableFirmware = lib.mkForce false;
-  hardware.firmware = [pkgs.raspberrypiWirelessFirmware];
+  hardware = {
+    enableRedistributableFirmware = lib.mkForce false;
+    firmware = [pkgs.raspberrypiWirelessFirmware]; # Keep this to make sure wifi works
+    i2c.enable = true;
+    deviceTree.filter = "bcm2837-rpi-zero*.dtb";
+    deviceTree.overlays = [
+      {
+        name = "enable-i2c";
+        dtsText = ''
+          /dts-v1/;
+          /plugin/;
+          / {
+            compatible = "brcm,bcm2837";
+            fragment@0 {
+              target = <&i2c1>;
+              __overlay__ {
+                status = "okay";
+              };
+            };
+          };
+        '';
+      }
+    ];
+  };
 
   boot = {
     kernelPackages = pkgs.linuxPackages_rpi02w;