FMC: create drivers/fmc and toplevel Kconfig question

This commit creates the drivers/fmc directory and puts the necessary
hooks for kbuild and kconfig. The code is currently a placeholder
that only registers an empty bus.

Signed-off-by: Alessandro Rubini <[e-mail]>
Acked-by: Juan David Gonzalez Cobas <[e-mail]>
Acked-by: Emilio G. Cota <[e-mail]>
Acked-by: Samuel Iglesias Gonsalvez <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

MAINTAINERS

···
 S:	Odd fixes
 F:	drivers/block/floppy.c
 
+FMC SUBSYSTEM
+M:	Alessandro Rubini <[e-mail]>
+W:	http://www.ohwr.org/projects/fmc-bus
+S:	Supported
+F:	drivers/fmc/
+F:	include/linux/fmc*.h
+F:	include/linux/ipmi-fru.h
+K:	fmc_d.*register
+
 FPU EMULATOR
 M:	Bill Metzenthen <[e-mail]>
 W:	http://floatingpoint.sourceforge.net/emulator/index.html

drivers/Kconfig

···
 
 source "drivers/reset/Kconfig"
 
+source "drivers/fmc/Kconfig"
+
 endmenu

drivers/Makefile

···
 obj-$(CONFIG_VME_BUS)		+= vme/
 obj-$(CONFIG_IPACK_BUS)		+= ipack/
 obj-$(CONFIG_NTB)		+= ntb/
+obj-$(CONFIG_FMC)		+= fmc/

drivers/fmc/Kconfig

···
+#
+# FMC (ANSI-VITA 57.1) bus support
+#
+
+menuconfig FMC
+	tristate "FMC support"
+	help
+
+	  FMC (FPGA Mezzanine Carrier) is a mechanical and electrical
+	  standard for mezzanine cards that plug into a carrier board.
+	  This kernel subsystem supports the matching between carrier
+	  and mezzanine based on identifiers stored in the internal I2C
+	  EEPROM, as well as having carrier-independent drivers.
+
+	  The framework was born outside of the kernel and at this time
+	  the off-tree code base is more complete.  Code and documentation
+	  is at git://ohwr.org/fmc-projects/fmc-bus.git .

drivers/fmc/Makefile

···
+
+obj-$(CONFIG_FMC) += fmc.o
+
+fmc-y = fmc-core.o

drivers/fmc/fmc-core.c

···
+/* Temporary placeholder so the empty code can build */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+
+static struct bus_type fmc_bus_type = {
+	.name = "fmc",
+};
+
+static int fmc_init(void)
+{
+	return bus_register(&fmc_bus_type);
+}
+
+static void fmc_exit(void)
+{
+	bus_unregister(&fmc_bus_type);
+}
+
+module_init(fmc_init);
+module_exit(fmc_exit);
+
+MODULE_LICENSE("GPL");