X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/f5efceca6644ed0e546ae4f3e559507bb87ae933..c2bc4a90827f28abb6b51eae659a1f80a65c0497:/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 7597ca6..2dcc539 100644
--- a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
+++ b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
@@ -1,18 +1,22 @@
+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
 """Chip Definition for MCP2221"""
 
 import os
 import time
+import atexit
+
 import hid
 
 # Here if you need it
 MCP2221_HID_DELAY = float(os.environ.get("BLINKA_MCP2221_HID_DELAY", 0))
-# Use to set delay between reset and device reopen
+# Use to set delay between reset and device reopen. if negative, don't reset at all
 MCP2221_RESET_DELAY = float(os.environ.get("BLINKA_MCP2221_RESET_DELAY", 0.5))
 
 # from the C driver
 # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz
 # others (???) determined during driver developement
-# pylint: disable=bad-whitespace
 RESP_ERR_NOERR = 0x00
 RESP_ADDR_NACK = 0x25
 RESP_READ_ERR = 0x7F
@@ -35,7 +39,6 @@ RESP_I2C_WRITINGNOSTOP = 0x45  # ???
 MCP2221_RETRY_MAX = 50
 MCP2221_MAX_I2C_DATA_LEN = 60
 MASK_ADDR_NACK = 0x40
-# pylint: enable=bad-whitespace
 
 
 class MCP2221:
@@ -53,12 +56,23 @@ class MCP2221:
     def __init__(self):
         self._hid = hid.device()
         self._hid.open(MCP2221.VID, MCP2221.PID)
-        self._reset()
+        # make sure the device gets closed before exit
+        atexit.register(self.close)
+        if MCP2221_RESET_DELAY >= 0:
+            self._reset()
         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 hid 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
@@ -119,6 +133,7 @@ class MCP2221:
 
     def _reset(self):
         self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
+        self._hid.close()
         time.sleep(MCP2221_RESET_DELAY)
         start = time.monotonic()
         while time.monotonic() - start < 5:
@@ -190,7 +205,7 @@ 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()
@@ -199,7 +214,7 @@ 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(
@@ -224,6 +239,8 @@ class MCP2221:
             # yay chunk sent!
             while self._i2c_state() == RESP_I2C_PARTIALDATA:
                 time.sleep(0.001)
+            if not buffer:
+                break
             start += chunk
             retries = 0
 
@@ -231,7 +248,7 @@ class MCP2221:
         for _ in range(MCP2221_RETRY_MAX):
             status = self._i2c_status()
             if status[20] & MASK_ADDR_NACK:
-                raise RuntimeError("I2C slave address was NACK'd")
+                raise OSError("I2C slave address was NACK'd")
             usb_cmd_status = status[8]
             if usb_cmd_status == 0:
                 break
@@ -268,7 +285,7 @@ class MCP2221:
 
         # and now the read part
         while (end - start) > 0:
-            for retry in range(MCP2221_RETRY_MAX):
+            for _ in range(MCP2221_RETRY_MAX):
                 # the actual read
                 resp = self._hid_xfer(b"\x40")
                 # check for success
@@ -286,6 +303,8 @@ class MCP2221:
                     continue
                 if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL):
                     break
+            else:
+                raise RuntimeError("I2C read error: max retries reached.")
 
             # move data into buffer
             chunk = min(end - start, 60)
@@ -295,7 +314,7 @@ class MCP2221:
 
     # pylint: enable=too-many-arguments
 
-    def i2c_configure(self, baudrate=100000):
+    def _i2c_configure(self, baudrate=100000):
         """Configure I2C"""
         self._hid_xfer(
             bytes(
@@ -326,7 +345,7 @@ class MCP2221:
         out_start=0,
         out_end=None,
         in_start=0,
-        in_end=None
+        in_end=None,
     ):
         """Write data from buffer_out to an address and then
         read data from an address and into buffer_in
@@ -341,7 +360,8 @@ class MCP2221:
             # try a write
             try:
                 self.i2c_writeto(addr, b"\x00")
-            except RuntimeError:  # no reply!
+            except OSError:  # no reply!
+                # We got a NACK, which could be correct
                 continue
             # store if success
             found.append(addr)