Another option for Ws2812 - direct spi from the pi with 1 wire (#631)

* Removed -HUP so the default -TERM signal is sent instead.
- hyperiond only listens for TERM and INT. HUP is often used to get an exe to reread its config

Changed pgrep to add '-x' so it wont partial match on the exe name.
- I have multiple instances with multiple hyperiond-instance1 names
- this ensures the service script only kills the right process

* reversing errant change to hyperion.systemd.sh

* This add a new device type - ws2812spi.

I've (ab)used the SPI interface to send the correct timing pulses to keep the ws2812 happy.
THE RATE IS IMPORTANT!
A FIXED CORE_CLK IS IMPORTANT!

Attach the SPI MOSI pin on the Pi to the DIN pin on your ws2812

        "device" :
        {
                "name"       : "MyPi",
                "type"       : "ws2812spi",
                "colorOrder" : "grb",
                "output"     : "/dev/spidev0.0",
                "rate"       : 3800000
        },

* updated hyperiond.test-binary

* Updated default SPI speed to the "correct" value.
My Pi was undervolted so was dropping the core clock confusing everything

* Code cleanups
explicitly set the final 3 bytes to 0

* Removed latchtime option - not applicable

* updated test binary


Former-commit-id: d3c19c8374999f7a554bb25ca181a8a483f86289

hyperiond.test-binary.REMOVED.git-id

@@ -1 +1 @@
-5d75f380f2bd74d3cd6b574f0a7d05850786216b
+23f1b917ec588d71521aa698edf446a2e8c0ea5d

libsrc/leddevice/CMakeLists.txt

@@ -75,6 +75,7 @@ if(ENABLE_SPIDEV)
 			${CURRENT_SOURCE_DIR}/LedDeviceLpd8806.h
 			${CURRENT_SOURCE_DIR}/LedDeviceP9813.h
 			${CURRENT_SOURCE_DIR}/LedDeviceWs2801.h
+			${CURRENT_SOURCE_DIR}/LedDeviceWs2812SPI.h
 			${CURRENT_SOURCE_DIR}/LedDeviceAPA102.h
 	)
 	SET(Leddevice_SOURCES
@@ -84,6 +85,7 @@ if(ENABLE_SPIDEV)
 			${CURRENT_SOURCE_DIR}/LedDeviceLpd8806.cpp
 			${CURRENT_SOURCE_DIR}/LedDeviceP9813.cpp
 			${CURRENT_SOURCE_DIR}/LedDeviceWs2801.cpp
+			${CURRENT_SOURCE_DIR}/LedDeviceWs2812SPI.cpp
 			${CURRENT_SOURCE_DIR}/LedDeviceAPA102.cpp
 	)
 endif(ENABLE_SPIDEV)

libsrc/leddevice/LedDeviceFactory.cpp

@@ -14,6 +14,7 @@
 	#include "LedDeviceLpd8806.h"
 	#include "LedDeviceP9813.h"
 	#include "LedDeviceWs2801.h"
+	#include "LedDeviceWs2812SPI.h"
 	#include "LedDeviceAPA102.h"
 #endif
 
@@ -142,6 +143,16 @@ LedDevice * LedDeviceFactory::construct(const Json::Value & deviceConfig)
 
 		device = deviceWs2801;
 	}
+	else if (type == "ws2812spi")
+	{
+		const std::string output = deviceConfig["output"].asString();
+		const unsigned rate      = deviceConfig.get("rate",2857143).asInt();
+
+		LedDeviceWs2812SPI* deviceWs2812SPI = new LedDeviceWs2812SPI(output, rate);
+		deviceWs2812SPI->open();
+
+		device = deviceWs2812SPI;
+	}
 #endif
 #ifdef ENABLE_TINKERFORGE
 	else if (type=="tinkerforge")

libsrc/leddevice/LedDeviceWs2812SPI.cpp

@@ -0,0 +1,57 @@
+
+// STL includes
+#include <cstring>
+#include <cstdio>
+#include <iostream>
+
+// Linux includes
+#include <fcntl.h>
+#include <sys/ioctl.h>
+
+// hyperion local includes
+#include "LedDeviceWs2812SPI.h"
+
+LedDeviceWs2812SPI::LedDeviceWs2812SPI(const std::string& outputDevice, const unsigned baudrate) :
+	LedSpiDevice(outputDevice, baudrate, 0),
+	mLedCount(0)
+{
+	// empty
+}
+
+int LedDeviceWs2812SPI::write(const std::vector<ColorRgb> &ledValues)
+{
+	mLedCount = ledValues.size();
+
+// 3 colours, 4 spi bytes per colour + 3 frame end latch bytes
+#define COLOURS_PER_LED		3
+#define SPI_BYTES_PER_COLOUR	4
+#define SPI_BYTES_PER_LED 	COLOURS_PER_LED * SPI_BYTES_PER_COLOUR
+
+	unsigned spi_size = mLedCount * SPI_BYTES_PER_LED + 3;
+	if(_spiBuffer.size() != spi_size){
+                _spiBuffer.resize(spi_size, 0x00);
+	}
+
+	unsigned spi_ptr = 0;
+        for (unsigned i=0; i< mLedCount; ++i) {
+		uint32_t colorBits = ((unsigned int)ledValues[i].red << 16) 
+			| ((unsigned int)ledValues[i].green << 8) 
+			| ledValues[i].blue;
+
+		for (int j=SPI_BYTES_PER_LED - 1; j>=0; j--) {
+			_spiBuffer[spi_ptr+j] = bitpair_to_byte[ colorBits & 0x3 ];
+			colorBits >>= 2;
+		}
+		spi_ptr += SPI_BYTES_PER_LED;
+        }
+	_spiBuffer[spi_ptr++] = 0;
+	_spiBuffer[spi_ptr++] = 0;
+	_spiBuffer[spi_ptr++] = 0;
+
+	return writeBytes(spi_size, _spiBuffer.data());
+}
+
+int LedDeviceWs2812SPI::switchOff()
+{
+	return write(std::vector<ColorRgb>(mLedCount, ColorRgb{0,0,0}));
+}

libsrc/leddevice/LedDeviceWs2812SPI.h

@@ -0,0 +1,52 @@
+#pragma once
+
+// STL includes
+#include <string>
+
+// hyperion incluse
+#include "LedSpiDevice.h"
+
+///
+/// Implementation of the LedDevice interface for writing to Ws2801 led device.
+///
+class LedDeviceWs2812SPI : public LedSpiDevice
+{
+public:
+	///
+	/// Constructs the LedDevice for a string containing leds of the type Ws2812SPI
+	///
+	/// @param outputDevice The name of the output device (eg '/etc/SpiDev.0.0')
+	/// @param baudrate The used baudrate for writing to the output device
+	///
+	LedDeviceWs2812SPI(const std::string& outputDevice,
+					const unsigned baudrate);
+
+	LedDeviceWs2812SPI(const std::string& outputDevice,
+					const unsigned baudrate,
+					const unsigned latchTime);
+
+	///
+	/// Writes the led color values to the led-device
+	///
+	/// @param ledValues The color-value per led
+	/// @return Zero on succes else negative
+	///
+	virtual int write(const std::vector<ColorRgb> &ledValues);
+
+	/// Switch the leds off
+	virtual int switchOff();
+
+private:
+
+	/// the number of leds (needed when switching off)
+	size_t mLedCount;
+	std::vector<uint8_t> _spiBuffer;
+
+        uint8_t bitpair_to_byte[4] = {
+                0b10001000,
+                0b10001100,
+                0b11001000,
+                0b11001100,
+        };
+
+};