added utility script to find correct usb device for the fingerprint reader.

nixos/modules/nixos/system/fingerprint-reader-on-laptop-lid/default.nix

@@ -11,6 +11,7 @@
 # ID 27c6:609c Shenzhen Goodix Technology Co.,Ltd
 # On Framework 16 the USB is:
 # Bus 005 Device 007: ID 27c6:609c Shenzhen Goodix Technology Co.,Ltd
+# Use `findfp.sh` to find the correct USB device.
 { config, lib, pkgs, ... }:
 let
   cfg = config.mySystem.system.fingerprint-reader-on-laptop-lid;

nixos/modules/nixos/system/fingerprint-reader-on-laptop-lid/findfp.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+find_usb_device() {
+    local idVendor=$1
+    local idProduct=$2
+    local device_id="${idVendor}:${idProduct}"
+
+    for device in /sys/bus/usb/devices/*; do
+        if [ -f "$device/idVendor" ] && [ -f "$device/idProduct" ]; then
+            vendor=$(cat "$device/idVendor")
+            product=$(cat "$device/idProduct")
+            if [ "${vendor}:${product}" = "$device_id" ]; then
+                echo "$device"
+                return 0
+            fi
+        fi
+    done
+
+    return 1
+}
+
+# Example usage
+idVendor="27c6"
+idProduct="609c"
+
+device_path=$(find_usb_device "$idVendor" "$idProduct")
+
+if [ -n "$device_path" ]; then
+    echo "Device found at: $device_path"
+
+    # Print additional information
+    manufacturer=$(cat "$device_path/manufacturer" 2>/dev/null)
+    product=$(cat "$device_path/product" 2>/dev/null)
+
+    echo "Manufacturer: ${manufacturer:-N/A}"
+    echo "Product: ${product:-N/A}"
+else
+    echo "Device not found"
+fi