Merge pull request #758 from how2flow/amlogic

[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / generic_linux / sysfs_pwmout.py

diff --git a/src/adafruit_blinka/microcontroller/generic_linux/sysfs_pwmout.py b/src/adafruit_blinka/microcontroller/generic_linux/sysfs_pwmout.py
index ae4da4b78124eefbd15b5b35723efc984ac5f0bf..9bf26025d76406c3ae27f12e0a943583c6a9b5c8 100644 (file)
--- a/src/adafruit_blinka/microcontroller/generic_linux/sysfs_pwmout.py
+++ b/src/adafruit_blinka/microcontroller/generic_linux/sysfs_pwmout.py
@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
 """
 Much code from https://github.com/vsergeev/python-periphery/blob/master/periphery/pwm.py
 Copyright (c) 2015-2016 vsergeev / Ivan (Vanya) A. Sergeev
@@ -26,10 +29,6 @@ class PWMError(IOError):
 
 class PWMOut:
     """Pulse Width Modulation Output Class"""
-    # Number of retries to check for successful PWM export on open
-    PWM_STAT_RETRIES = 10
-    # Delay between check for scucessful PWM export on open (100ms)
-    PWM_STAT_DELAY = 0.1
 
     # Number of retries to check for successful PWM export on open
     PWM_STAT_RETRIES = 10
@@ -109,13 +108,15 @@ class PWMOut:
 
         try:
             with open(
-                os.path.join(channel_path, self._unexport_path), "w"
+                os.path.join(channel_path, self._unexport_path), "w", encoding="utf-8"
             ) as f_unexport:
                 f_unexport.write("%d\n" % self._pwmpin)
-        except IOError as e:
+        except IOError:
             pass  # not unusual, it doesnt already exist
         try:
-            with open(os.path.join(channel_path, self._export_path), "w") as f_export:
+            with open(
+                os.path.join(channel_path, self._export_path), "w", encoding="utf-8"
+            ) as f_export:
                 f_export.write("%d\n" % self._pwmpin)
         except IOError as e:
             raise PWMError(e.errno, "Exporting PWM pin: " + e.strerror) from IOError
@@ -130,13 +131,14 @@ class PWMOut:
                         channel_path, self._pin_path.format(self._pwmpin), "period"
                     ),
                     "w",
+                    encoding="utf-8",
                 ):
                     break
             except IOError as e:
                 if e.errno != EACCES or (
                     e.errno == EACCES and i == PWMOut.PWM_STAT_RETRIES - 1
                 ):
-                    raise PWMError(e.errno, "Opening PWM period: " + e.strerror)
+                    raise PWMError(e.errno, "Opening PWM period: " + e.strerror) from e
             sleep(PWMOut.PWM_STAT_DELAY)
 
         # self._set_enabled(False) # This line causes a write error when trying to enable
@@ -156,13 +158,14 @@ class PWMOut:
     def deinit(self):
         """Deinit the sysfs PWM."""
         if self._channel is not None:
-            self.duty_cycle = 0
             try:
                 channel_path = os.path.join(
                     self._sysfs_path, self._channel_path.format(self._channel)
                 )
                 with open(
-                    os.path.join(channel_path, self._unexport_path), "w"
+                    os.path.join(channel_path, self._unexport_path),
+                    "w",
+                    encoding="utf-8",
                 ) as f_unexport:
                     f_unexport.write("%d\n" % self._pwmpin)
             except IOError as e:
@@ -191,7 +194,7 @@ class PWMOut:
             attr,
         )
 
-        with open(path, "w") as f_attr:
+        with open(path, "w", encoding="utf-8") as f_attr:
             # print(value, path)
             f_attr.write(value + "\n")
 
@@ -206,7 +209,7 @@ class PWMOut:
             attr,
         )
 
-        with open(path, "r") as f_attr:
+        with open(path, "r", encoding="utf-8") as f_attr:
             return f_attr.read().strip()
 
     # Mutable properties