Leddevices source tree refactoring (#461)

* rework structure of leddevice source tree

* fix data type vor v4l sig detection value in webui

* automate leddevicefactory.cpp

libsrc/leddevice/dev_spi/LedDeviceWs2812SPI.cpp

@@ -0,0 +1,95 @@
+#include "LedDeviceWs2812SPI.h"
+
+/*
+From the data sheet:
+
+(TH+TL=1.25μs±600ns)
+
+T0H,	 0 code, high level time,	 0.40µs ±0.150ns
+T0L,	 0 code, low level time,	 0.85µs ±0.150ns
+T1H,	 1 code, high level time,	 0.80µs ±0.150ns
+T1L,	 1 code, low level time,	 0.45µs ±0.150ns
+WT,	 Wait for the processing time,	 NA
+Trst,	 Reset code,low level time,	 50µs (not anymore... need 300uS for latest revision)
+
+To normalise the pulse times so they fit in 4 SPI bits:
+
+On the assumption that the "low" time doesnt matter much
+
+A SPI bit time of 0.40uS = 2.5 Mbit/sec
+T0 is sent as 1000
+T1 is sent as 1100
+
+With a bit of excel testing, we can work out the maximum and minimum speeds:
+2106000 MIN
+2590500 AVG
+3075000 MAX
+
+Wait time:
+Not Applicable for WS2812
+
+Reset time:
+using the max of 3075000, the bit time is 0.325
+Reset time is 300uS = 923 bits = 116 bytes
+
+*/
+
+LedDeviceWs2812SPI::LedDeviceWs2812SPI(const QJsonObject &deviceConfig)
+	: ProviderSpi()
+	, SPI_BYTES_PER_COLOUR(4)
+	, SPI_FRAME_END_LATCH_BYTES(116)
+	, bitpair_to_byte {
+		0b10001000,
+		0b10001100,
+		0b11001000,
+		0b11001100,
+	}
+{
+	_deviceReady = init(deviceConfig);
+}
+
+LedDevice* LedDeviceWs2812SPI::construct(const QJsonObject &deviceConfig)
+{
+	return new LedDeviceWs2812SPI(deviceConfig);
+}
+
+bool LedDeviceWs2812SPI::init(const QJsonObject &deviceConfig)
+{
+	_baudRate_Hz = 2600000;
+	if ( !ProviderSpi::init(deviceConfig) )
+	{
+		return false;
+	}
+	WarningIf(( _baudRate_Hz < 2106000 || _baudRate_Hz > 3075000 ), _log, "SPI rate %d outside recommended range (2106000 -> 3075000)", _baudRate_Hz);
+
+	_ledBuffer.resize(_ledRGBCount * SPI_BYTES_PER_COLOUR + SPI_FRAME_END_LATCH_BYTES, 0x00);
+
+	return true;
+}
+
+int LedDeviceWs2812SPI::write(const std::vector<ColorRgb> &ledValues)
+{
+	unsigned spi_ptr = 0;
+	const int SPI_BYTES_PER_LED = sizeof(ColorRgb) * SPI_BYTES_PER_COLOUR;
+
+	for (const ColorRgb& color : ledValues)
+	{
+		uint32_t colorBits = ((unsigned int)color.red << 16)
+			| ((unsigned int)color.green << 8)
+			| color.blue;
+
+		for (int j=SPI_BYTES_PER_LED - 1; j>=0; j--)
+		{
+			_ledBuffer[spi_ptr+j] = bitpair_to_byte[ colorBits & 0x3 ];
+			colorBits >>= 2;
+		}
+		spi_ptr += SPI_BYTES_PER_LED;
+	}
+
+	for (int j=0; j < SPI_FRAME_END_LATCH_BYTES; j++)
+	{
+		_ledBuffer[spi_ptr++] = 0;
+	}
+
+	return writeBytes(_ledBuffer.size(), _ledBuffer.data());
+}