Add a general bit-bang SPI upper-half driver

drivers/Makefile

@@ -1,7 +1,7 @@
 ############################################################################
 # drivers/Makefile
 #
-#   Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -62,6 +62,7 @@ include power$(DELIM)Make.defs
 include sensors$(DELIM)Make.defs
 include sercomm$(DELIM)Make.defs
 include serial$(DELIM)Make.defs
+include spi$(DELIM)Make.defs
 include syslog$(DELIM)Make.defs
 include usbdev$(DELIM)Make.defs
 include usbhost$(DELIM)Make.defs

drivers/input/Make.defs

@@ -33,7 +33,7 @@
 #
 ############################################################################
 
-# Don't build anything if there is no NX support for input devices
+# Don't build anything if there is no support for input devices
 
 ifeq ($(CONFIG_INPUT),y)
 

drivers/spi/Kconfig

@@ -3,22 +3,15 @@
 # see misc/tools/kconfig-language.txt.
 #
 
-config SPI
-	bool "SPI Driver Support"
-	default n
-	---help---
-		This selection enables selection of common SPI options.  This option
-		should be enabled by all platforms that support SPI interfaces.
-		See include/nuttx/spi/spi.h for further SPI driver information.
-
 if SPI
+
 config SPI_OWNBUS
 	bool "SPI single device"
 	default n
 	---help---
 		Set if there is only one active device on the SPI bus.  No locking or
 		SPI configuration will be performed. It is not necessary for clients to
-		lock, re-configure, etc..
+		lock, re-configure, etc.
 
 config SPI_EXCHANGE
 	bool "SPI exchange"
@@ -36,5 +29,11 @@ config SPI_CMDDATA
 		either 9-bit SPI (yech) or 8-bit SPI and a GPIO output that selects
 		between command and data.
 
-endif
+config SPI_BITBANG
+	bool "SPI bit-bang device"
+	default n
+	---help---
+		Enable support for a generic SPI bit-bang device.
+		See include/nuttx/spi/spi_bitbang.h for further information.
 
+endif