X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/de652f72b1884328ee22ec36deaa6320addd32e7..04727af7b654a50b4611d328217c0d8d0b1ffd84:/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 66d406d..fb9edf3 100644
--- a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
+++ b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
@@ -6,7 +6,7 @@ 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
@@ -51,7 +51,8 @@ class MCP2221:
     def __init__(self):
         self._hid = hid.device()
         self._hid.open(MCP2221.VID, MCP2221.PID)
-        self._reset()
+        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
@@ -188,7 +189,7 @@ 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()
@@ -197,7 +198,7 @@ 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(
@@ -222,6 +223,8 @@ class MCP2221:
             # yay chunk sent!
             while self._i2c_state() == RESP_I2C_PARTIALDATA:
                 time.sleep(0.001)
+            if not buffer:
+                break
             start += chunk
             retries = 0
 
@@ -284,6 +287,8 @@ 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)
@@ -293,7 +298,7 @@ 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(
@@ -324,7 +329,7 @@ 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