+/*
+ * max5322.c:
+ * Extend wiringPi with the MAX5322 SPI Digital to Analog convertor
+ * Copyright (c) 2012-2013 Gordon Henderson
+ ***********************************************************************
+ * This file is part of wiringPi:
+ * https://projects.drogon.net/raspberry-pi/wiringpi/
+ *
+ * wiringPi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * wiringPi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with wiringPi.
+ * If not, see <http://www.gnu.org/licenses/>.
+ ***********************************************************************
+ */
+
+#include <wiringPi.h>
+#include <wiringPiSPI.h>
+
+#include "max5322.h"
+
+/*
+ * myAnalogWrite:
+ * Write analog value on the given pin
+ *********************************************************************************
+ */
+
+static void myAnalogWrite (struct wiringPiNodeStruct *node, int pin, int value)
+{
+ unsigned char spiData [2] ;
+ unsigned char chanBits, dataBits ;
+ int chan = pin - node->pinBase ;
+
+ if (chan == 0)
+ chanBits = 0b01000000 ;
+ else
+ chanBits = 0b01010000 ;
+
+ chanBits |= ((value >> 4) & 0x0F) ;
+ dataBits = ((value << 4) & 0xF0) ;
+
+ spiData [0] = chanBits ;
+ spiData [1] = dataBits ;
+
+ wiringPiSPIDataRW (node->fd, spiData, 2) ;
+}
+
+/*
+ * max5322Setup:
+ * Create a new wiringPi device node for an max5322 on the Pi's
+ * SPI interface.
+ *********************************************************************************
+ */
+
+int max5322Setup (const int pinBase, int spiChannel)
+{
+ struct wiringPiNodeStruct *node ;
+ unsigned char spiData [2] ;
+
+ if (wiringPiSPISetup (spiChannel, 8000000) < 0) // 10MHz Max
+ return -1 ;
+
+ node = wiringPiNewNode (pinBase, 2) ;
+
+ node->fd = spiChannel ;
+ node->analogWrite = myAnalogWrite ;
+
+// Enable both DACs
+
+ spiData [0] = 0b11100000 ;
+ spiData [1] = 0 ;
+
+ wiringPiSPIDataRW (node->fd, spiData, 2) ;
+
+ return 0 ;
+}