comedi: Uncripple 8255-based DIO subdevices

(Note: upstream comedi configuration has been overhauled, so this patch
does not apply there.)

Several comedi drivers call subdev_8255_init() (declared in
"drivers/staging/comedi/drivers/8255.h") to set up one or more DIO
subdevices.  This should be provided by the 8255.ko module, but unless
the CONFIG_COMEDI_8255 or CONFIG_COMEDI_8255_MODULE macro is defined,
the 8255.h header uses a dummy inline version of the function instead.
This means the comedi devices end up with an "unused" subdevice with 0
channels instead of a "DIO" subdevice with 24 channels!

This patch provides a non-interactive COMEDI_8255 option and selects it
whenever the COMEDI_PCI_DRIVERS or COMEDI_PCMCIA_DRIVERS options are
selected.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/Kconfig

@@ -16,6 +16,7 @@ config COMEDI_DEBUG
 config COMEDI_PCI_DRIVERS
 	tristate "Comedi PCI drivers"
 	depends on COMEDI && PCI
+	select COMEDI_8255
 	default N
 	---help---
 	  Enable lots of comedi PCI drivers to be built
@@ -23,6 +24,7 @@ config COMEDI_PCI_DRIVERS
 config COMEDI_PCMCIA_DRIVERS
 	tristate "Comedi PCMCIA drivers"
 	depends on COMEDI && PCMCIA && PCCARD
+	select COMEDI_8255
 	default N
 	---help---
 	  Enable lots of comedi PCMCIA and PCCARD drivers to be built
@@ -33,3 +35,6 @@ config COMEDI_USB_DRIVERS
 	default N
 	---help---
 	  Enable lots of comedi USB drivers to be built
+
+config COMEDI_8255
+	tristate

drivers/staging/comedi/drivers/Makefile

@@ -8,8 +8,10 @@ obj-$(CONFIG_COMEDI)			+= comedi_test.o
 obj-$(CONFIG_COMEDI)			+= comedi_parport.o
 obj-$(CONFIG_COMEDI)			+= pcm_common.o
 
+# Comedi 8255 module
+obj-$(CONFIG_COMEDI_8255)		+= 8255.o
+
 # Comedi PCI drivers
-obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= 8255.o
 obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= acl7225b.o
 obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= addi_apci_035.o
 obj-$(CONFIG_COMEDI_PCI_DRIVERS)	+= addi_apci_1032.o