Update pin.py

[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / amlogic / meson_g12_common / pin.py

diff --git a/src/adafruit_blinka/microcontroller/amlogic/meson_g12_common/pin.py b/src/adafruit_blinka/microcontroller/amlogic/meson_g12_common/pin.py
index 165bca71db19a9a3b4c7340212f4aaf5f7ca5b9d..41cf8f2e5918b3f560fc1c054d3ac41ca9545ca8 100644 (file)
--- a/src/adafruit_blinka/microcontroller/amlogic/meson_g12_common/pin.py
+++ b/src/adafruit_blinka/microcontroller/amlogic/meson_g12_common/pin.py
@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
 """
 G12A, G12B, and SM1 Common Definitions
 Ref:
@@ -8,9 +11,11 @@ Linux kernel 5.4.y (mainline)
     linux/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
 """
 
+from typing import Optional
+import os
 import re
-from adafruit_blinka.microcontroller.generic_linux.libgpiod_pin import Pin
 import gpiod
+from adafruit_blinka.microcontroller.generic_linux.libgpiod_pin import Pin
 
 chip0 = gpiod.Chip("0")
 chip1 = gpiod.Chip("1")
@@ -107,18 +112,18 @@ UART1_RX = GPIOX_13
 uartPorts = ((1, UART1_TX, UART1_RX),)
 
 
-def get_dts_alias(device: str) -> str:
+def get_dts_alias(device: str) -> Optional[str]:
     """Get the Device Tree Alias"""
     uevent_path = "/sys/bus/platform/devices/" + device + "/uevent"
-    with open(uevent_path, "r") as fd:
-        pattern = r"^OF_ALIAS_0=(.*)$"
-        uevent = fd.read().split("\n")
-        for line in uevent:
-            match = re.search(pattern, line)
-            if match:
-                return match.group(1).upper()
-
-        return None
+    if os.path.exists(uevent_path):
+        with open(uevent_path, "r", encoding="utf-8") as fd:
+            pattern = r"^OF_ALIAS_0=(.*)$"
+            uevent = fd.read().split("\n")
+            for line in uevent:
+                match = re.search(pattern, line)
+                if match:
+                    return match.group(1).upper()
+    return None
 
 
 # ordered as i2cId, sclId, sdaId