add readme

README.md

@@ -0,0 +1,40 @@
+# infinitime-builder
+
+Build InfiniTime firmware images using [nix](https://nixos.org/).
+
+## Building
+
+```shell
+nix --experimental-features 'nix-command flakes' build
+```
+
+The images to flash will be put into `./result`
+
+(If you already have flakes enabled you can skip the `--experimental-features` bit)
+
+## Customizing
+
+You can customize the build image by editing `package.nix` and adding them to the `patches` array like:
+
+```nix
+patches = [
+  # grap the patch directly from github
+  (fetchpatch {
+    name = "double-click-settings.patch";
+    url = "https://github.com/InfiniTimeOrg/InfiniTime/commit/d395f6f0857f082ab3e7fc66cb591b12bbd9cd65.patch";
+    sha256 = "sha256-2Jng8JDTU7Zd42qD25CQNeF9dQRSLNwWq9IL+ik0ok0=";
+  })
+  # or from a local file (don't forget to add the patch to git before building)
+  ./local-patch.patch
+]
+```
+
+## Updating
+
+To change the version being build you can edit the `src` directive with a different `rev` and `hash`.
+
+You can determine the correct `hash` for a revision by running
+
+```shell
+nix --experimental-features 'nix-command flakes' run github:nix-community/nurl -- https://github.com/InfiniTimeOrg/InfiniTime <revision> --submodules
+```

package.nix

@@ -9,7 +9,8 @@
   fetchzip,
   patch,
   git,
-  fetchgit,
+  fetchFromGitHub,
+  fetchpatch,
 }: let
   infinitime-nrf5-sdk = nrf5-sdk.overrideAttrs (old: {
     version = "15.3.0";
@@ -21,14 +22,18 @@
 in stdenv.mkDerivation rec {
   name = "infinitime";
 
-  src = fetchgit {
-    url = "https://github.com/InfiniTimeOrg/InfiniTime";
+  src = fetchFromGitHub {
+    owner = "InfiniTimeOrg";
+    repo = "InfiniTime";
     rev = "1.13.0";
-    hash = "sha256-d2zW1JxoQ2j1Yezp3AeDDY7KObyqZ3N8JO4WCbV02sc=";
-    deepClone = true;
+    hash = "sha256-aY1G60Rb+D7iAWsqn1j4SkL+mpXT34otWvS29UFidzM=";
     fetchSubmodules = true;
   };
 
+  patches = [
+    # put your patches here
+  ];
+
   nativeBuildInputs = [
     cmake
     lv_img_conv