initial cleanup and mapping

wiringPi/wiringPiSPI.c

@@ -0,0 +1,121 @@
+/*
+ * wiringPiSPI.c:
+ *	Simplified SPI access routines
+ *	Copyright (c) 2012 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 <stdint.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <linux/spi/spidev.h>
+
+#include "wiringPi.h"
+
+#include "wiringPiSPI.h"
+
+
+// The SPI bus parameters
+//	Variables as they need to be passed as pointers later on
+
+const static char       *spiDev0  = "/dev/spidev0.0" ;
+const static char       *spiDev1  = "/dev/spidev0.1" ;
+const static uint8_t     spiMode  = 0 ;
+const static uint8_t     spiBPW   = 8 ;
+const static uint16_t    spiDelay = 0 ;
+
+static uint32_t    spiSpeeds [2] ;
+static int         spiFds [2] ;
+
+
+/*
+ * wiringPiSPIGetFd:
+ *	Return the file-descriptor for the given channel
+ *********************************************************************************
+ */
+
+int wiringPiSPIGetFd (int channel)
+{
+  return spiFds [channel & 1] ;
+}
+
+
+/*
+ * wiringPiSPIDataRW:
+ *	Write and Read a block of data over the SPI bus.
+ *	Note the data ia being read into the transmit buffer, so will
+ *	overwrite it!
+ *	This is also a full-duplex operation.
+ *********************************************************************************
+ */
+
+int wiringPiSPIDataRW (int channel, unsigned char *data, int len)
+{
+  struct spi_ioc_transfer spi ;
+
+  channel &= 1 ;
+
+  spi.tx_buf        = (unsigned long)data ;
+  spi.rx_buf        = (unsigned long)data ;
+  spi.len           = len ;
+  spi.delay_usecs   = spiDelay ;
+  spi.speed_hz      = spiSpeeds [channel] ;
+  spi.bits_per_word = spiBPW ;
+
+  return ioctl (spiFds [channel], SPI_IOC_MESSAGE(1), &spi) ;
+}
+
+
+/*
+ * wiringPiSPISetup:
+ *	Open the SPI device, and set it up, etc.
+ *********************************************************************************
+ */
+
+int wiringPiSPISetup (int channel, int speed)
+{
+  int fd ;
+
+  channel &= 1 ;
+
+  if ((fd = open (channel == 0 ? spiDev0 : spiDev1, O_RDWR)) < 0)
+    return wiringPiFailure (WPI_ALMOST, "Unable to open SPI device: %s\n", strerror (errno)) ;
+
+  spiSpeeds [channel] = speed ;
+  spiFds    [channel] = fd ;
+
+// Set SPI parameters.
+//	Why are we reading it afterwriting it? I've no idea, but for now I'm blindly
+//	copying example code I've seen online...
+
+  if (ioctl (fd, SPI_IOC_WR_MODE, &spiMode)         < 0)
+    return wiringPiFailure (WPI_ALMOST, "SPI Mode Change failure: %s\n", strerror (errno)) ;
+  
+  if (ioctl (fd, SPI_IOC_WR_BITS_PER_WORD, &spiBPW) < 0)
+    return wiringPiFailure (WPI_ALMOST, "SPI BPW Change failure: %s\n", strerror (errno)) ;
+
+  if (ioctl (fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed)   < 0)
+    return wiringPiFailure (WPI_ALMOST, "SPI Speed Change failure: %s\n", strerror (errno)) ;
+
+  return fd ;
+}