waveshare2in13v2: Enable hardware early

Enable the clock and analog parts when configuring the mode. In probably
all use cases a drawing operation is following soon after anyway.
Putting the device to sleep disables these hardware parts again.

waveshare2in13v2/controller.go

@@ -66,16 +66,11 @@ func configDisplayMode(ctrl controller, mode PartialUpdate, lut LUT) {
 	ctrl.sendCommand(writeDisplayOptionRegister)
 	ctrl.sendData([]byte{0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00})
 
-	if mode == Partial {
+	// Start up the parts likely used by a draw operation soon.
 	ctrl.sendCommand(displayUpdateControl2)
-		ctrl.sendData([]byte{
+	ctrl.sendData([]byte{displayUpdateEnableClock | displayUpdateEnableAnalog})
-			displayUpdateEnableClock |
-				displayUpdateEnableAnalog,
-		})
 
 	ctrl.sendCommand(masterActivation)
-	}
-
 	ctrl.waitUntilIdle()
 }
 

waveshare2in13v2/controller_test.go

@@ -92,6 +92,8 @@ func TestConfigDisplayMode(t *testing.T) {
 				{cmd: borderWaveformControl, data: []byte{0x03}},
 				{cmd: writeLutRegister, data: bytes.Repeat([]byte{'F'}, 70)},
 				{cmd: 0x37, data: []byte{0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00}},
+				{cmd: displayUpdateControl2, data: []byte{0xc0}},
+				{cmd: masterActivation},
 			},
 		},
 		{