staging: comedi: add NI USB-6501 support

Enable support for the National Instruments USB-6501 module.

The NI USB-6501 is a Full-Speed USB 2.0 (12 Mbit/s) device that
provides 24 digital I/O lines channels and one 32-bit counter.

This is a preliminary version:
	GPIO: works
	counter: doesn't work
Signed-off-by: Luca Ellero <luca.ellero@brickedbrain.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/Kconfig

@@ -1209,6 +1209,17 @@ config COMEDI_DT9812
 	  To compile this driver as a module, choose M here: the module will be
 	  called dt9812.
 
+config COMEDI_NI_USB6501
+	tristate "NI USB-6501 support"
+	---help---
+	  Enable support for the National Instruments USB-6501 module.
+
+	  The NI USB-6501 is a Full-Speed USB 2.0 (12 Mbit/s) device that
+	  provides 24 digital I/O lines channels and one 32-bit counter.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ni_usb6501.
+
 config COMEDI_USBDUX
 	tristate "ITL USB-DUX-D support"
 	---help---

drivers/staging/comedi/drivers/Makefile

@@ -125,6 +125,7 @@ obj-$(CONFIG_COMEDI_QUATECH_DAQP_CS)	+= quatech_daqp_cs.o
 
 # Comedi USB drivers
 obj-$(CONFIG_COMEDI_DT9812)		+= dt9812.o
+obj-$(CONFIG_COMEDI_NI_USB6501)		+= ni_usb6501.o
 obj-$(CONFIG_COMEDI_USBDUX)		+= usbdux.o
 obj-$(CONFIG_COMEDI_USBDUXFAST)		+= usbduxfast.o
 obj-$(CONFIG_COMEDI_USBDUXSIGMA)	+= usbduxsigma.o