X-Git-Url: https://git.ayoreis.com/hackapet/Adafruit_Blinka.git/blobdiff_plain/6db6ef855f798996075d2919ca924ec31983f7f1..56feca73d6ec6b79c9b030d8ab06cc00574d6013:/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py

diff --git a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
index 30f45f6..fb8193c 100644
--- a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
+++ b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
@@ -2,6 +2,7 @@
 
 import os
 import time
+import atexit
 import hid
 
 # Here if you need it
@@ -51,13 +52,30 @@ class MCP2221:
     def __init__(self):
         self._hid = hid.device()
         self._hid.open(MCP2221.VID, MCP2221.PID)
+        # make sure the device gets closed before exit
+        atexit.register(self.close)
         if MCP2221_RESET_DELAY >= 0:
-            self._reset()
+            try:
+                self._reset()
+            except OSError:
+                # this might fail on Linux with the hid_mcp2221 native
+                # driver and a short reset delay -- if it fails,
+                # close the device before reraising
+                self.close()
+                raise
         self._gp_config = [0x07] * 4  # "don't care" initial value
         for pin in range(4):
             self.gp_set_mode(pin, self.GP_GPIO)  # set to GPIO mode
             self.gpio_set_direction(pin, 1)  # set to INPUT
 
+    def close(self):
+        """Close the device. Does nothing if the device is not open."""
+        self._hid.close()
+
+    def __del__(self):
+        # try to close the device before destroying the instance
+        self.close()
+
     def _hid_xfer(self, report, response=True):
         """Perform HID Transfer"""
         # first byte is report ID, which =0 for MCP2221
@@ -189,7 +207,7 @@ class MCP2221:
             # bus release will need "a few hundred microseconds"
             time.sleep(0.001)
 
-    # pylint: disable=too-many-arguments
+    # pylint: disable=too-many-arguments,too-many-branches
     def _i2c_write(self, cmd, address, buffer, start=0, end=None):
         if self._i2c_state() != 0x00:
             self._i2c_cancel()
@@ -198,7 +216,7 @@ class MCP2221:
         length = end - start
         retries = 0
 
-        while (end - start) > 0:
+        while (end - start) > 0 or not buffer:
             chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN)
             # write out current chunk
             resp = self._hid_xfer(
@@ -223,6 +241,8 @@ class MCP2221:
             # yay chunk sent!
             while self._i2c_state() == RESP_I2C_PARTIALDATA:
                 time.sleep(0.001)
+            if not buffer:
+                break
             start += chunk
             retries = 0