Add device tree filter for Pi 4 B

hosts/pi/default.nix

@@ -17,8 +17,59 @@
     };
     deviceTree = {
       enable = true;
+      filter = "*rpi-4-*.dtb";
       overlays = [
-        { name = "hifiberry-digi-pro"; dtboFile = "${pkgs.device-tree_rpi.overlays}/hifiberry-digi-pro.dtbo"; }
+        {
+          # Adapted from: https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/hifiberry-digi-pro-overlay.dts
+          # changes:
+          # - modified top-level "compatible" field from bcm2835 to bcm2711
+          # - s/i2s_clk_consumer/i2s/ (name on bcm2711 platform)
+          name = "hifiberry-digi-pro";
+          dtsText = ''
+            /dts-v1/;
+            /plugin/;
+
+            / {
+                compatible = "brcm,bcm2711";
+
+                fragment@0 {
+                    target = <&i2s>;
+                    __overlay__ {
+                        status = "okay";
+                    };
+                };
+
+                fragment@1 {
+                    target = <&i2c1>;
+                    __overlay__ {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        status = "okay";
+
+                        wm8804@3b {
+                            #sound-dai-cells = <0>;
+                            compatible = "wlf,wm8804";
+                            reg = <0x3b>;
+                            PVDD-supply = <&vdd_3v3_reg>;
+                            DVDD-supply = <&vdd_3v3_reg>;
+                            status = "okay";
+                        };
+                    };
+                };
+
+                fragment@2 {
+                    target = <&sound>;
+                    __overlay__ {
+                        compatible = "hifiberry,hifiberry-digi";
+                        i2s-controller = <&i2s>;
+                        status = "okay";
+                        clock44-gpio = <&gpio 5 0>;
+                        clock48-gpio = <&gpio 6 0>;
+                    };
+                };
+            };
+          '';
+        }
       ];
     };
     firmware = with pkgs; [