Rename to `BaseDisplayDriver`; ili9341 changes

diff --git a/src/seedsigner/hardware/displays/ST7789.py b/src/seedsigner/hardware/displays/ST7789.py
index b399aa6..6fb05ce 100644
--- a/src/seedsigner/hardware/displays/ST7789.py
+++ b/src/seedsigner/hardware/displays/ST7789.py
@@ -4,12 +4,12 @@ import time
 import array
 from dataclasses import dataclass
 
-from seedsigner.hardware.displays.display_driver import DisplayDriver
+from seedsigner.hardware.displays.display_driver import BaseDisplayDriver
 
 
 
 @dataclass
-class ST7789(DisplayDriver):
+class ST7789(BaseDisplayDriver):
     """
     The original SeedSigner display driver.
 
diff --git a/src/seedsigner/hardware/displays/display_driver.py b/src/seedsigner/hardware/displays/display_driver.py
index 9903476..0870e6e 100644
--- a/src/seedsigner/hardware/displays/display_driver.py
+++ b/src/seedsigner/hardware/displays/display_driver.py
@@ -10,13 +10,12 @@ ALL_DISPLAY_TYPES = [DISPLAY_TYPE__ST7789, DISPLAY_TYPE__ILI9341, DISPLAY_TYPE__
     
 
 @dataclass
-class DisplayDriver:
+class BaseDisplayDriver:
     _width: int
     _height: int
 
-
     def __str__(self):
-        return f"DisplayDriver(display_type={self.display_type}, width={self.width}, height={self.height})"
+        return f"DisplayDriver(display_type={getattr(self, 'display_type', None)}, width={self.width}, height={self.height})"
 
 
     @property
@@ -30,16 +29,26 @@ class DisplayDriver:
 
 
     def invert(self, enabled: bool = True):
-        """Invert how the display interprets colors"""
-        raise Exception("Must be implemented in child class")
+        """
+        Invert how the display interprets colors.
+        Implementation in child classes is optional.
+        """
+        pass
 
 
     def show_image(self, image, x_start: int = 0, y_start: int = 0):
-        raise Exception("Must be implemented in child class")
-    
+        """
+        The main rendering call to the display driver.
+        Must be implemented in child classes.
+        """
+        raise Exception("show_image() must be implemented in child classes")
+
 
     def cleanup(self):
-        """Cleanup resources related to the display driver."""
+        """
+        Cleanup resources used by the display driver.
+        Implementation in child classes is optional.
+        """
         pass
 
 
@@ -52,7 +61,7 @@ class DisplayDriverFactory:
     """
 
     @classmethod
-    def instantiate_display_driver(cls, display_type: str = DISPLAY_TYPE__ST7789, width: int = None, height: int = None) -> DisplayDriver:
+    def instantiate_display_driver(cls, display_type: str = DISPLAY_TYPE__ST7789, width: int = None, height: int = None) -> BaseDisplayDriver:
         if display_type not in ALL_DISPLAY_TYPES:
             raise ValueError(f"Invalid display type: {display_type}")
 
diff --git a/src/seedsigner/hardware/displays/ili9341.py b/src/seedsigner/hardware/displays/ili9341.py
index 1330aa7..93492e6 100644
--- a/src/seedsigner/hardware/displays/ili9341.py
+++ b/src/seedsigner/hardware/displays/ili9341.py
@@ -35,6 +35,8 @@ from PIL import ImageDraw
 import RPi.GPIO as GPIO
 from spidev import SpiDev
 
+from seedsigner.hardware.displays.display_driver import BaseDisplayDriver
+
 
 # Constants for interacting with display registers.
 ILI9341_TFTWIDTH    = 240
@@ -129,16 +131,14 @@ def image_to_data(image):
     return arr.tobytes()
 
 
-class ILI9341(object):
+class ILI9341(BaseDisplayDriver):
     """Representation of an ILI9341 TFT LCD."""
 
-    def __init__(self, dc=22, rst=13, led=12, width=ILI9341_TFTWIDTH,
-        height=ILI9341_TFTHEIGHT, rotation=90):
-        """Create an instance of the display using SPI communication.  Must
-        provide the GPIO pin number for the D/C pin and the SPI driver.  Can
-        optionally provide the GPIO pin number for the reset pin as the rst
-        parameter.
-        """
+    def __post_init__(self):
+        dc=22
+        rst=13
+        led=12
+        rotation=90
         spi = SpiDev(0, 0)
         # spi.mode = 0b10  # [CPOL|CPHA] -> polarity 1, phase 0
         spi.max_speed_hz = 64_000_000
@@ -146,8 +146,6 @@ class ILI9341(object):
         self._dc = dc
         self._rst = rst
         self._spi = spi
-        self.width = width
-        self.height = height
         self.rotation = rotation
         self.inverted = False
         # if self._gpio is None:
@@ -165,15 +163,7 @@ class ILI9341(object):
             GPIO.output(self._rst, GPIO.HIGH)
 
         # Create an image buffer.
-        self.buffer = Image.new('RGB', (width, height))
-
-    # @property
-    # def width(self):
-    #     return self.width
-
-    # @property
-    # def height(self):
-    #     return self.height
+        self.buffer = Image.new('RGB', (self.width, self.height))
 
 
     def send(self, data, is_data=True, chunk_size=4096):
diff --git a/src/seedsigner/hardware/displays/st7789_mpy.py b/src/seedsigner/hardware/displays/st7789_mpy.py
index 2aad703..b69999c 100644
--- a/src/seedsigner/hardware/displays/st7789_mpy.py
+++ b/src/seedsigner/hardware/displays/st7789_mpy.py
@@ -57,7 +57,7 @@ import RPi.GPIO as GPIO
 from dataclasses import dataclass
 from math import sin, cos
 
-from seedsigner.hardware.displays.display_driver import DisplayDriver
+from seedsigner.hardware.displays.display_driver import BaseDisplayDriver
 
 #
 # This allows sphinx to build the docs
@@ -233,7 +233,7 @@ def color565(red, green=0, blue=0):
 
 
 @dataclass
-class ST7789(DisplayDriver):
+class ST7789(BaseDisplayDriver):
     """
     ST7789 driver class