Adding a SPI driver for pn532

The driver seems to work well.
I tested it on Linux with i.mx233-based board using hardware SPI.
I tried to modify the build files as well, but it's probably a little messy.
I'm not sure whether it will work on other *nix OSes,
so it's probably better to limit the driver to Linux only using build system.

libnfc/buses/Makefile.am

@@ -3,8 +3,8 @@
 AM_CPPFLAGS = $(all_includes) $(LIBNFC_CFLAGS)
 
 noinst_LTLIBRARIES = libnfcbuses.la
-libnfcbuses_la_SOURCES = uart.c uart.h
+libnfcbuses_la_SOURCES = uart.c uart.h spi.c spi.h
 libnfcbuses_la_CFLAGS = -I$(top_srcdir)/libnfc
 
-EXTRA_DIST = uart_posix.c uart_win32.c
+EXTRA_DIST = uart_posix.c uart_win32.c spi_posix.c
 

libnfc/buses/spi.c

@@ -0,0 +1,44 @@
+/*-
+ * Public platform independent Near Field Communication (NFC) library
+ *
+ * Copyright (C) 2013 Evgeny Boger
+ * Copyright (C) 2009, 2010 Roel Verdult
+ * Copyright (C) 2009, 2010 Romuald Conty
+ *
+ * This program 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.
+ *
+ * This program 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+/**
+ * @file spi.c
+ * @brief SPI driver wrapper
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif // HAVE_CONFIG_H
+
+#include "spi.h"
+
+#include <nfc/nfc.h>
+#include "nfc-internal.h"
+
+// Test if we are dealing with unix operating systems
+#ifndef _WIN32
+// The POSIX SPI port implementation
+#  include "spi_posix.c"
+#else
+// The windows SPI port implementation
+# error "Not implemented"
+#endif /* _WIN32 */

libnfc/buses/spi.h

@@ -0,0 +1,60 @@
+/*-
+ * Public platform independent Near Field Communication (NFC) library
+ *
+ * Copyright (C) 2013 Evgeny Boger
+ * Copyright (C) 2009, 2010 Roel Verdult
+ * Copyright (C) 2010, 2011 Romain Tarti?re
+ * Copyright (C) 2009, 2010, 2011 Romuald Conty
+ *
+ * This program 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.
+ *
+ * This program 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+/**
+ * @file spi.h
+ * @brief SPI driver header
+ */
+
+#ifndef __NFC_BUS_SPI_H__
+#  define __NFC_BUS_SPI_H__
+
+#  include <sys/time.h>
+
+#  include <stdio.h>
+#  include <string.h>
+#  include <stdlib.h>
+
+#  include <linux/spi/spidev.h>
+
+#  include <nfc/nfc-types.h>
+
+// Define shortcut to types to make code more readable
+typedef void *spi_port;
+#  define INVALID_SPI_PORT (void*)(~1)
+#  define CLAIMED_SPI_PORT (void*)(~2)
+
+spi_port spi_open(const char *pcPortName);
+void    spi_close(const spi_port sp);
+
+void    spi_set_speed(spi_port sp, const uint32_t uiPortSpeed);
+void    spi_set_mode(spi_port sp, const uint32_t uiPortMode);
+uint32_t spi_get_speed(const spi_port sp);
+
+int     spi_receive(spi_port sp, uint8_t *pbtRx, const size_t szRx, bool lsb_first);
+int     spi_send(spi_port sp, const uint8_t *pbtTx, const size_t szTx, bool lsb_first);
+int     spi_send_receive(spi_port sp, const uint8_t *pbtTx, const size_t szTx, uint8_t *pbtRx, const size_t szRx, bool lsb_first);
+
+char  **spi_list_ports(void);
+
+#endif // __NFC_BUS_SPI_H__