Keybow 2040: Run IS31 I2C at 400KHz.

Speed up Keybow 2040 I2C further to ~5ms (200FPS) by increasing from the default 100KHz to 400KHz I2C.

Since Keybow 2040 does not include a Qw'St connector, we need not worry about other I2C devices.

Signed-off-by: Phil Howard <github@gadgetoid.com>

boards/pimoroni/keybow_2040/keybow_2040_rgb.py

@@ -1,4 +1,5 @@
 import board
+import busio
 from micropython import const
 
 from adafruit_bus_device.i2c_device import I2CDevice
@@ -23,7 +24,8 @@ def __init__(
             self,
             size: int = 16  # Kept for backward compatibility
     ):
-        self.i2c_device = I2CDevice(board.I2C(), 0x74)
+        self.i2c = i2c = busio.I2C( board.SCL, board.SDA, frequency=400_000)
+        self.i2c_device = I2CDevice(i2c, 0x74)
         self.out_buffer = bytearray(144)
         self._pixels = 16
         self._frame = 0