turny: fix SPI/GPIO config for newer kernels

- Add complete config.txt settings with u-boot boot lines + spi=on
- Override sdImage.populateFirmwareCommands to use configtxt module output
- Mount firmware partition and add activation script to sync config.txt
- Load spi_bcm2835 and bcm2835_gpiomem kernel modules
- Add udev rule for gpiomem subsystem (not just gpio)
- Relax ProtectKernelTunables so service can access GPIO
- Update turny flake input to rppal-based CS pin fix

custom-pkgs/md2pdf-cli/package.nix

@@ -0,0 +1,160 @@
+{
+  lib,
+  pkgs,
+}:
+let
+  stylesheet = pkgs.writeText "md2pdf-style.css" ''
+    body {
+      font-family: "Noto Sans", sans-serif;
+      font-size: 11px;
+      max-width: 100%;
+      margin: 0;
+      padding: 15px;
+      line-height: 1.4;
+    }
+    h1 {
+      font-size: 22px;
+      border-bottom: 2px solid #333;
+      padding-bottom: 5px;
+      break-after: avoid;
+    }
+    h2 {
+      font-size: 18px;
+      margin-top: 25px;
+      border-bottom: 1px solid #ccc;
+      padding-bottom: 3px;
+      break-after: avoid;
+    }
+    h3 {
+      font-size: 14px;
+      margin-top: 15px;
+      break-after: avoid;
+    }
+    table {
+      border-collapse: collapse;
+      width: 100%;
+      font-size: 10px;
+      margin: 10px 0;
+    }
+    th {
+      background: #f0f0f0;
+      border: 1px solid #ccc;
+      padding: 4px 6px;
+      text-align: left;
+      break-after: avoid;
+      break-inside: avoid;
+    }
+    td {
+      border: 1px solid #ccc;
+      padding: 4px 6px;
+      vertical-align: top;
+      break-inside: avoid;
+    }
+    tr {
+      break-inside: avoid;
+      break-after: auto;
+    }
+    code {
+      background: #f5f5f5;
+      padding: 1px 3px;
+      border-radius: 2px;
+      font-family: "Noto Sans Mono", monospace;
+      font-size: 10px;
+    }
+    pre {
+      background: #f5f5f5;
+      padding: 10px;
+      border-radius: 4px;
+      overflow-x: auto;
+      font-size: 10px;
+    }
+    pre code {
+      background: none;
+      padding: 0;
+    }
+    blockquote {
+      border-left: 3px solid #ccc;
+      margin-left: 0;
+      padding-left: 10px;
+      color: #555;
+    }
+    img {
+      max-width: 100%;
+      height: auto;
+      border: 1px solid #ddd;
+      margin: 5px 0;
+      break-inside: avoid;
+    }
+    em {
+      color: #666;
+    }
+    a {
+      color: #0066cc;
+    }
+  '';
+
+  md-to-pdf = pkgs.buildNpmPackage {
+    pname = "md-to-pdf";
+    version = "5.2.5";
+
+    src = pkgs.fetchFromGitHub {
+      owner = "simonhaenisch";
+      repo = "md-to-pdf";
+      rev = "v5.2.5";
+      hash = "sha256-6Zr4jidQ6cX2t6jKFqEnCSqvRtw4gZkqDKdv9SIyDC4=";
+    };
+
+    npmDepsHash = "sha256-AGn8g/nbkvWi4o6ENCnt7VexjfBIoDz+tl9eYvy+bao=";
+
+    # canvas is an optional native dependency that fails to build in nix;
+    # md-to-pdf works fine without it (puppeteer is used for PDF generation)
+    npmFlags = [ "--ignore-scripts" ];
+
+    postInstall = ''
+      rm -rf $out/lib/node_modules/md-to-pdf/node_modules/canvas
+    '';
+  };
+in
+pkgs.stdenv.mkDerivation {
+  pname = "md2pdf";
+  version = "1.0.0";
+
+  src = ./.;
+
+  dontBuild = true;
+
+  nativeBuildInputs = [ ];
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/bin $out/share/md2pdf
+
+    cp ${stylesheet} $out/share/md2pdf/style.css
+
+    cat > $out/bin/md2pdf << 'WRAPPER'
+    #!/bin/sh
+    export PUPPETEER_EXECUTABLE_PATH="@chromium@/bin/chromium"
+    export PATH="@chromium@/bin''${PATH:+:''${PATH}}"
+    exec "@md-to-pdf@/bin/md-to-pdf" \
+      --stylesheet "@stylesheet@" \
+      --pdf-options '{"format":"A4","margin":{"top":"10mm","bottom":"10mm","left":"12mm","right":"12mm"},"printBackground":true}' \
+      "$@"
+    WRAPPER
+
+    substituteInPlace $out/bin/md2pdf \
+      --replace-fail "@chromium@" "${pkgs.chromium}" \
+      --replace-fail "@md-to-pdf@" "${md-to-pdf}" \
+      --replace-fail "@stylesheet@" "$out/share/md2pdf/style.css"
+
+    chmod +x $out/bin/md2pdf
+
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "Convert Markdown to PDF with Noto Sans styling and tight margins";
+    mainProgram = "md2pdf";
+    platforms = lib.platforms.linux;
+  };
+}