readme: update build instructions for flakes

README.md

@@ -8,20 +8,22 @@
 
 ### Reproducible build with Nix
 
-See the `mcu` folder of the [nix-scripts repository](https://git.m-labs.hk/M-Labs/nix-scripts).
+Thermostat firmware is packaged using the [Nix](https://nixos.org) Flakes system. Install Nix 2.4+ and enable flakes by adding ``experimental-features = nix-command flakes`` to ``nix.conf`` (e.g. ``~/.config/nix/nix.conf``). 
+
+Once you have Flakes enabled, you can use ``nix build`` to build the firmware.
 
 ### Development environment
 
-Clone this repository and [nix-scripts](https://git.m-labs.hk/M-Labs/nix-scripts).
+Clone this repository and with Nix Flakes enabled, use the following commands:
 
 ```shell
-nix-shell -I nix-scripts=[path to nix-scripts checkout]
+nix develop
 cargo build --release
 ```
 
-The resulting ELF file will be located under `target/thumbv7em-none-eabihf/release/thermostat`
+The resulting ELF file will be located under `target/thumbv7em-none-eabihf/release/thermostat`.
 
-Alternatively, you can install the Rust toolchain without Nix using rustup; see the channel manifest file in nix-scripts (`channel-rust-nightly.toml`) to determine which Rust version to use.
+Alternatively, you can install the Rust toolchain without Nix using rustup; see the Rust manifest file pulled in `flake.nix` to determine which Rust version to use.
 
 ## Debugging
 

flake.nix

@@ -1,87 +1,79 @@
 {
-    description = "Firmware for the Sinara 8451 Thermostat";
+	description = "Firmware for the Sinara 8451 Thermostat";
 
-    inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-21.11;
-    inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
+	inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-21.11;
+	inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
 
-    outputs = { self, nixpkgs, mozilla-overlay }:
-        let
-            pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import mozilla-overlay) ]; };
-            rustManifest = pkgs.fetchurl {
-                url = "https://static.rust-lang.org/dist/2020-10-30/channel-rust-nightly.toml";
-                sha256 = "0iygcwzh8s0lfdghj5809krvzifc1ii1wm4sd3qqn7s0rz1s14hi";
-            };
+	outputs = { self, nixpkgs, mozilla-overlay }:
+		let
+			pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import mozilla-overlay) ]; };
+			rustManifest = pkgs.fetchurl {
+				url = "https://static.rust-lang.org/dist/2020-10-30/channel-rust-nightly.toml";
+				sha256 = "0iygcwzh8s0lfdghj5809krvzifc1ii1wm4sd3qqn7s0rz1s14hi";
+			};
 
-            targets = [
-                "thumbv7em-none-eabihf"
-            ];
-            rustChannelOfTargets = _channel: _date: targets:
-                (pkgs.lib.rustLib.fromManifestFile rustManifest {
-                    inherit (pkgs) stdenv lib fetchurl patchelf;
-                    }).rust.override {
-                    inherit targets;
-                    extensions = ["rust-src"];
-                };
-            rust = rustChannelOfTargets "nightly" null targets;
-            rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
-                rustc = rust;
-                cargo = rust;
-            });
-            thermostat = rustPlatform.buildRustPackage rec {
-                name = "thermostat";
-                version = "0.0.0";
+			targets = [
+				"thumbv7em-none-eabihf"
+			];
+			rustChannelOfTargets = _channel: _date: targets:
+				(pkgs.lib.rustLib.fromManifestFile rustManifest {
+					inherit (pkgs) stdenv lib fetchurl patchelf;
+					}).rust.override {
+					inherit targets;
+					extensions = ["rust-src"];
+				};
+      rust = rustChannelOfTargets "nightly" null targets;
+      rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
+        rustc = rust;
+        cargo = rust;
+      });
+			thermostat = rustPlatform.buildRustPackage rec {
+				name = "thermostat";
+				version = "0.0.0";
 
-                src = self;
-                cargoLock = { 
-                    lockFile = ./Cargo.lock;
-                    outputHashes = {
-                        "stm32-eth-0.2.0" = "sha256-HXRr/NDhdIKqyjdA4D8ZmcO1dDpDawdlYPUOwcEbPQk=";
-                        "stm32f4xx-hal-0.8.3" = "sha256-MOv7tVtVMxr3IYMaN0Q8EQWxv3rubmCxjXMXuw/ZKAw=";
-                    };
-                };
+				src = self;
+				cargoLock = { 
+					lockFile = ./Cargo.lock;
+					outputHashes = {
+						"stm32-eth-0.2.0" = "sha256-HXRr/NDhdIKqyjdA4D8ZmcO1dDpDawdlYPUOwcEbPQk=";
+						"stm32f4xx-hal-0.8.3" = "sha256-MOv7tVtVMxr3IYMaN0Q8EQWxv3rubmCxjXMXuw/ZKAw=";
+					};
+				};
 
-                patchPhase = "";
-                nativeBuildInputs = [ pkgs.llvm ];
-                buildPhase = ''
-                export CARGO_HOME=$(mktemp -d cargo-home.XXX)
-                cargo build --release --bin thermostat
-                '';
+				nativeBuildInputs = [ pkgs.llvm ];
+				buildPhase = ''
+				  cargo build --release --bin thermostat
+				'';
 
-                checkPhase = ''
-                    cargo test --target=${pkgs.rust.toRustTarget pkgs.stdenv.targetPlatform};
-                '';
+				installPhase = ''
+          mkdir -p $out $out/nix-support
+          cp target/thumbv7em-none-eabihf/release/thermostat $out/thermostat.elf
+          echo file binary-dist $out/thermostat.elf >> $out/nix-support/hydra-build-products
+          llvm-objcopy -O binary target/thumbv7em-none-eabihf/release/thermostat $out/thermostat.bin
+          echo file binary-dist $out/thermostat.bin >> $out/nix-support/hydra-build-products
+				'';
 
-                # binaryName defaults to the `name` arg (i.e. the Rust package name);
-                # it is used as the Cargo binary filename
-                installPhase = ''
-                mkdir -p $out $out/nix-support
-                cp target/thumbv7em-none-eabihf/release/thermostat $out/thermostat.elf
-                echo file binary-dist $out/thermostat.elf >> $out/nix-support/hydra-build-products
-                llvm-objcopy -O binary target/thumbv7em-none-eabihf/release/thermostat $out/thermostat.bin
-                echo file binary-dist $out/thermostat.bin >> $out/nix-support/hydra-build-products
-                '';
+				dontFixup = true;
+			};
+		in rec {
+			packages.x86_64-linux = rec {
+				inherit thermostat;
+			};
 
-                dontFixup = true;
-            };
-        in rec {
-            packages.x86_64-linux = rec {
-                inherit thermostat;
-            };
+			hydraJobs = {
+				inherit (packages.x86_64-linux) thermostat;
+			};
 
-            hydraJobs = {
-                inherit (packages.x86_64-linux) thermostat;
-            };
-
-            devShell.x86_64-linux = pkgs.mkShell {
-                name = "thermostat-dev-shell";
-                buildInputs = with pkgs; [
-                    rustPlatform.rust.rustc
-                    rustPlatform.rust.cargo
-                    gcc openocd dfu-util
-                    ] ++ (with python3Packages; [
-                        numpy matplotlib
-                    ]);
-            };
-            defaultPackage.x86_64-linux = thermostat;
-      };
+			devShell.x86_64-linux = pkgs.mkShell {
+				name = "thermostat-dev-shell";
+				buildInputs = with pkgs; [
+					rustPlatform.rust.rustc
+					rustPlatform.rust.cargo
+					gcc openocd dfu-util
+					] ++ (with python3Packages; [
+						numpy matplotlib
+					]);
+			};
+			defaultPackage.x86_64-linux = thermostat;
+	  };
 }