Add error checking and retries to the read and write functions

adafruit_lc709203f.py

@@ -62,6 +62,8 @@
 LC709203F_CMD_ALARMPERCENT = const(0x13)
 LC709203F_CMD_ALARMVOLTAGE = const(0x14)
 
+LC709203F_I2C_RETRY_COUNT = 10
+
 
 class CV:
     """struct helper"""
@@ -156,17 +158,26 @@ def init_RSOC(self) -> None:  # pylint: disable=invalid-name
     @property
     def cell_voltage(self) -> float:
         """Returns floating point voltage"""
-        return self._read_word(LC709203F_CMD_CELLVOLTAGE) / 1000
+        try:
+            return self._read_word(LC709203F_CMD_CELLVOLTAGE) / 1000
+        except OSError:
+            return None
 
     @property
     def cell_percent(self) -> float:
         """Returns percentage of cell capacity"""
-        return self._read_word(LC709203F_CMD_CELLITE) / 10
+        try:
+            return self._read_word(LC709203F_CMD_CELLITE) / 10
+        except OSError:
+            return None
 
     @property
     def cell_temperature(self) -> float:
         """Returns the temperature of the cell"""
-        return self._read_word(LC709203F_CMD_CELLTEMPERATURE) / 10 - 273.15
+        try:
+            return self._read_word(LC709203F_CMD_CELLTEMPERATURE) / 10 - 273.15
+        except OSError:
+            return None
 
     @cell_temperature.setter
     def cell_temperature(self, value: float) -> None:
@@ -281,14 +292,31 @@ def _read_word(self, command: int) -> int:
         self._buf[1] = command  # command / register
         self._buf[2] = self._buf[0] | 0x1  # read byte
 
-        with self.i2c_device as i2c:
-            i2c.write_then_readinto(
-                self._buf, self._buf, out_start=1, out_end=2, in_start=3, in_end=7
-            )
-        crc8 = self._generate_crc(self._buf[0:5])
-        if crc8 != self._buf[5]:
-            raise OSError("CRC failure on reading word")
-        return (self._buf[4] << 8) | self._buf[3]
+        for x in range(LC709203F_I2C_RETRY_COUNT):
+            try:
+                with self.i2c_device as i2c:
+                    i2c.write_then_readinto(
+                        self._buf,
+                        self._buf,
+                        out_start=1,
+                        out_end=2,
+                        in_start=3,
+                        in_end=7,
+                    )
+
+                crc8 = self._generate_crc(self._buf[0:5])
+                if crc8 != self._buf[5]:
+                    raise OSError("CRC failure on reading word")
+                return (self._buf[4] << 8) | self._buf[3]
+            except OSError as exception:
+                # print("OSError in read: ", x+1, "/10: ", exception)
+                if x == (LC709203F_I2C_RETRY_COUNT - 1):
+                    # Retry count reached
+                    # print("Retry count reached in read: ", exception)
+                    raise exception
+
+        # Code should never reach this point, add this to satisfy pylint R1710.
+        return None
 
     def _write_word(self, command: int, data: int) -> None:
         self._buf[0] = LC709203F_I2CADDR_DEFAULT * 2  # write byte
@@ -297,5 +325,14 @@ def _write_word(self, command: int, data: int) -> None:
         self._buf[3] = (data >> 8) & 0xFF
         self._buf[4] = self._generate_crc(self._buf[0:4])
 
-        with self.i2c_device as i2c:
-            i2c.write(self._buf[1:5])
+        for x in range(LC709203F_I2C_RETRY_COUNT):
+            try:
+                with self.i2c_device as i2c:
+                    i2c.write(self._buf[1:5])
+                return
+            except OSError as exception:
+                # print("OSError in write: ", x+1, "/10: ", exception)
+                if x == (LC709203F_I2C_RETRY_COUNT - 1):
+                    # Retry count reached
+                    # print("Retry count reached in write: ", exception)
+                    raise exception