set maximum SPI speed

The raspberry linux kernel updated the default spi frequency to 125MHz:

kernel: BCM270X_DT: Set spidev spi-max-frequency to 125MHz.
See raspberrypi/linux#2165.

The WS2801 LEDs can only handle 10 MHz, but when not set the default value is used, which is too much.
This commit explicit includes the spi package and sets the max speed for the spidev

Author: Trekky12

package.json

@@ -4,7 +4,8 @@
   "description": "A node.js library to control a WS2801 RGB LED stripe via SPI with your Raspberry Pi",
   "main": "rpi-ws2801.js",
   "dependencies": {
-    "microtime": "*"
+    "microtime": "*",
+    "spi":"*"
   },
   "devDependencies": {},
   "scripts": {

rpi-ws2801.js

@@ -1,5 +1,5 @@
-var fs        = require('fs');
 var microtime = require('microtime');
+var SPI       = require('spi');
 
 /*
  A node.js library to control a WS2801 RGB LED stripe via SPI with your Raspberry Pi
@@ -9,7 +9,7 @@ var microtime = require('microtime');
 function RPiWS2801(){
   this.spiDevice = '/dev/spidev0.0';
   this.numLEDs = 32;
-  this.spiFd = null; //filedescriptor for spidevice
+  this.spi = null; 
   this.inverted = false;
   this.reversed = false;	
   this.gamma = 2.5;
@@ -24,6 +24,8 @@ function RPiWS2801(){
     						            // manual of WS2801 says 500 is enough, however we need at least 1000
   this.lastWriteTime = microtime.now()-this.rowResetTime-1; //last time something was written to SPI
     												                                //required for save WS2801 reset	
+  // SPI max speed
+  this.maxSpeed = 1000000;
   // clear buffer    												                                
   this.values.fill(0);
 }
@@ -41,13 +43,16 @@ RPiWS2801.prototype = {
     if (spiDevice){
       this.spiDevice = spiDevice;
     }
-    // connect synchronously
+    
     try{
-      this.spiFd = fs.openSync(this.spiDevice, 'w');
+      this.spi = new SPI.Spi(this.spiDevice, {'maxSpeed' : this.maxSpeed}, function(s){
+          s.open();
+        });
     } catch (err) {
       console.error("error opening SPI device "+this.spiDevice, err);
       return false;
     }
+        
     this.numLEDs = numLEDs;
 
     this.channelCount = this.numLEDs*this.bytePerPixel;
@@ -66,14 +71,14 @@ RPiWS2801.prototype = {
    * disconnect from SPI port
    */
   disconnect : function(){
-    if (this.spiFd) fs.closeSync(this.spiFd);
+    if (this.spi) this.spi.close();
   },
 
   /*
    * send stored buffer with RGB values to WS2801 stripe
    */
   update: function(){
-    if (this.spiFd) {
+    if (this.spi) {
       this.sendRgbBuffer(this.values);
     }  
   },
@@ -120,7 +125,9 @@ RPiWS2801.prototype = {
       for (var i=0; i < buffer.length; i++){
         adjustedBuffer[i]=this.gammatable[buffer[i]];
       }
-      fs.writeSync(this.spiFd, adjustedBuffer, 0, buffer.length, null);
+
+      this.spi.write(adjustedBuffer);
+      
       this.lastWriteTime = microtime.now();
       return true;
     }
@@ -132,13 +139,13 @@ RPiWS2801.prototype = {
    * fill whole stripe with one color
    */
   fill: function(r,g,b){
-    if (this.spiFd) {      
+    if (this.spi) {      
       var colors = this.getRGBArray(r,g,b);
       var colorBuffer = new Buffer(this.channelCount);
       for (var i=0; i<(this.channelCount); i+=3){
         colorBuffer[i+0]=colors[0];
         colorBuffer[i+1]=colors[1];
-  	colorBuffer[i+2]=colors[2];
+        colorBuffer[i+2]=colors[2];
       }
       this.sendRgbBuffer(colorBuffer);
     }    	
@@ -148,7 +155,7 @@ RPiWS2801.prototype = {
    * set color of led index [red, green, blue] from 0 to 255
    */  
   setColor: function(ledIndex, color) {
-    if (this.spiFd) {
+    if (this.spi) {
       var colors = this.getRGBArray(color[0],color[1],color[2]);
       var r, g, b;
       r = colors[0] / 255;
@@ -165,7 +172,7 @@ RPiWS2801.prototype = {
    * set power of channel from 0 to 1
    */  
   setChannelPower: function(channelIndex, powerValue) {
-    if (this.spiFd) {  
+    if (this.spi) {  
       if(channelIndex > this.channelCount || channelIndex < 0) {
         return false;
       }
@@ -181,7 +188,7 @@ RPiWS2801.prototype = {
    * set RGB hexcolor to LED index
    */  
   setRGB: function(ledIndex, hexColor) {
-    if (this.spiFd) {
+    if (this.spi) {
       var rgb = this.getRGBfromHex(hexColor);
       var colors = this.getRGBArray(rgb.r,rgb.g,rgb.b);
       var redChannel = this.getRedChannelIndex(ledIndex);
@@ -222,9 +229,9 @@ RPiWS2801.prototype = {
 
   getRGBArray: function(r, g, b){
     var colorArray = new Array(3);
-    colorArray[this.redIndex] = r;
-    colorArray[this.greenIndex] = g;
-    colorArray[this.blueIndex] = b;
+    colorArray[this.redIndex] = r & 0xff;
+    colorArray[this.greenIndex] = g & 0xff;
+    colorArray[this.blueIndex] = b & 0xff;
     if(this.inverted) {
       colorArray[0] = (1 - colorArray[0]/255)*255;
       colorArray[1] = (1 - colorArray[1]/255)*255;