add enable option to config

rpi/config.nix

@@ -6,8 +6,13 @@ let
       lib.strings.concatStringsSep "\n" (render-dt-kvs opts);
     render-dt-param = x: "dtparam=" + x;
     render-dt-kv = k: v:
-      if isNull v then k else let vstr = toString v; in "${k}=${vstr}";
+      if isNull v.value then
-    render-dt-kvs = x: lib.attrsets.mapAttrsToList render-dt-kv x;
+        k
+      else
+        let vstr = toString v.value; in "${k}=${vstr}";
+    render-dt-kvs = x:
+      lib.attrsets.mapAttrsToList render-dt-kv
+      (lib.filterAttrs (k: v: v.enable) x);
     render-dt-overlay = { overlay, args }:
       "dtoverlay=" + overlay + "\n"
       + lib.strings.concatMapStringsSep "\n" render-dt-param args + "\n"
@@ -19,8 +24,8 @@ let
       lib.strings.concatMapStringsSep "\n" render-dt-overlay
       (lib.attrsets.mapAttrsToList (k: v: {
         overlay = k;
-        args = render-dt-kvs v;
+        args = render-dt-kvs v.params;
-      }) overlays);
+      }) (lib.filterAttrs (k: v: v.enable) overlays));
     render-config-section = k:
       { options, base-dt-params, dt-overlays }:
       let
@@ -40,29 +45,65 @@ in {
   options = {
     hardware.raspberry-pi = {
       config = let
+        rpi-config-param = {
+          options = {
+            enable = lib.mkEnableOption "attr";
+            value =
+              lib.mkOption { type = with lib.types; oneOf [ int str bool ]; };
+          };
+        };
+        dt-param = {
+          options = {
+            enable = lib.mkEnableOption "attr";
+            value = lib.mkOption {
+              type = with lib.types; nullOr (oneOf [ int str bool ]);
+              default = null;
+            };
+          };
+        };
+        dt-overlay = {
+          options = {
+            enable = lib.mkEnableOption "overlay";
+            params = lib.mkOption {
+              type = with lib.types; attrsOf (submodule dt-param);
+            };
+          };
+        };
         raspberry-pi-config-options = {
           options = {
             options = lib.mkOption {
-              type = with lib.types; attrsOf anything;
+              type = with lib.types; attrsOf (submodule rpi-config-param);
               default = { };
               example = {
-                enable_gic = true;
+                enable_gic = {
-                arm_boost = true;
+                  enable = true;
+                  value = true;
+                };
+                arm_boost = {
+                  enable = true;
+                  value = true;
+                };
               };
             };
             base-dt-params = lib.mkOption {
-              type = with lib.types; attrsOf anything;
+              type = with lib.types; attrsOf (submodule rpi-config-param);
               default = { };
               example = {
-                i2c = "on";
+                i2c = {
-                audio = "on";
+                  enable = true;
+                  value = "on";
+                };
+                audio = {
+                  enable = true;
+                  value = "on";
+                };
               };
               description = "parameters to pass to the base dtb";
             };
             dt-overlays = lib.mkOption {
-              type = with lib.types; attrsOf (attrsOf (nullOr str));
+              type = with lib.types; attrsOf (submodule dt-overlay);
               default = { };
-              example = { vc4-kms-v3d = { cma-256 = null; }; };
+              example = { vc4-kms-v3d = { cma-256 = { enable = true; }; }; };
               description = "dtb overlays to apply";
             };
           };

rpi/default.nix

@@ -20,21 +20,61 @@
   # Default config.txt on Raspberry Pi OS:
   # https://github.com/RPi-Distro/pi-gen/blob/master/stage1/00-boot-files/files/config.txt
   hardware.raspberry-pi.config = {
-    cm4 = { options = { otg_mode = true; }; };
+    cm4 = {
-    pi4 = { options = { arm_boost = true; }; };
+      options = {
+        otg_mode = {
+          enable = true;
+          value = true;
+        };
+      };
+    };
+    pi4 = {
+      options = {
+        arm_boost = {
+          enable = true;
+          value = true;
+        };
+      };
+    };
     all = {
       options = {
         # The firmware will start our u-boot binary rather than a
         # linux kernel.
-        kernel = "u-boot-rpi-arm64.bin";
+        kernel = {
-        arm_64bit = true;
+          enable = true;
-        enable_uart = true;
+          value = "u-boot-rpi-arm64.bin";
-        avoid_warnings = true;
+        };
-        camera_auto_detect = true;
+        arm_64bit = {
-        display_auto_detect = true;
+          enable = true;
-        disable_overscan = true;
+          value = true;
+        };
+        enable_uart = {
+          enable = true;
+          value = true;
+        };
+        avoid_warnings = {
+          enable = true;
+          value = true;
+        };
+        camera_auto_detect = {
+          enable = true;
+          value = true;
+        };
+        display_auto_detect = {
+          enable = true;
+          value = true;
+        };
+        disable_overscan = {
+          enable = true;
+          value = true;
+        };
+      };
+      dt-overlays = {
+        vc4-kms-v3d = {
+          enable = true;
+          params = { cma-256 = { enable = true; }; };
+        };
       };
-      dt-overlays = { vc4-kms-v3d = { }; };
     };
   };
 

rpi/i2c.nix

@@ -7,7 +7,12 @@ in {
   };
   config = lib.mkIf cfg.enable {
     hardware = {
-      raspberry-pi.config.all.base-dt-params = { i2c = "on"; };
+      raspberry-pi.config.all.base-dt-params = {
+        i2c = {
+          enable = true;
+          value = "on";
+        };
+      };
       i2c.enable = true;
     };
   };