Add get_egalax_edid_path

src/scripts/python/util/common.py

@@ -17,10 +17,14 @@ def max_match(a: str, b: str) -> str:
         b (str): second string
 
     Returns:
-        str: intersection of two strings
+        str: intersection of two strings OR  None if one or both strings are
+        empty or None
     """
     i = 0
 
+    if not a or not b:
+        return None
+
     if len(b) < len(a):
         a, b = b, a
 

src/scripts/python/util/egalax.py

@@ -5,6 +5,8 @@ touchpannel's drm output and its overal status.
 """
 
 from pathlib import Path
+from x import get_edid_dev_path
+from common import max_match
 
 VENDOR_ID = "0EEF"
 DEVICE_ID = "C000"
@@ -38,3 +40,28 @@ def is_egalax_connected() -> bool:
     """
     devpath = get_egalax_path()
     return bool(devpath)
+
+
+def get_egalax_edid_path() -> Path:
+    """return EDID path of touchpannel rdm
+
+    This function will find intersection of the edid pathes and eGalax hid
+    device and if this intersection and returns the maximum match.
+
+    Runtime: 160ms on average -> Not efficient
+
+    Returns:
+        Path: edid path of eGalax OR None if not found or device is'nt connected
+    """
+    egalax_dev = get_egalax_path()
+    if not egalax_dev:
+        return None
+    max_dir = "/sys/devices"
+    max_path = None
+    for path in get_edid_dev_path():
+        base_dir = max_match(str(path), str(egalax_dev))
+        if len(max_dir) < len(base_dir):
+            max_dir = base_dir
+            max_path = path
+    # TODO add sanity check (both edid and VENDOR:DEVICE are in that base)
+    return max_path