usb gadget: new "CDC Composite" gadget driver

This is a simple example of a composite gadget, combining two
Communications Class Device (CDC) functions:  ECM and ACM.

This provides a clear example of how the composite gadget framework
is intended to work.  It's surprising that MS-Windows (or at least,
XP and previous) won't "just work" with something this simple...

One /proc/bus/usb/devices listing looks like:

  T:  Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 46 Spd=480 MxCh= 0
  D:  Ver= 2.00 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
  P:  Vendor=0525 ProdID=a4aa Rev= 3.01
  S:  Manufacturer=Linux 2.6.26-rc6-pnut with net2280
  S:  Product=CDC Composite Gadget
  C:* #Ifs= 4 Cfg#= 1 Atr=c0 MxPwr=  2mA
  I:* If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=06 Prot=00 Driver=cdc_ether
  E:  Ad=83(I) Atr=03(Int.) MxPS=  16 Ivl=32ms
  I:  If#= 1 Alt= 0 #EPs= 0 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_ether
  I:* If#= 1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_ether
  E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
  E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
  I:* If#= 2 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=cdc_acm
  E:  Ad=86(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
  I:* If#= 3 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_acm
  E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
  E:  Ad=05(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

Not all USB peripheral controller hardware can support this driver.
All the highspeed-capable peripheral controllers with drivers now in
the mainline kernel seem to support this, as does omap_udc.  But
many full speed controllers don't have enough endpoints, or (as with
the PXA controllers) don't support altsettings.

Lightly tested.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
index 392487d..fcb5cb9 100644
--- a/drivers/usb/gadget/Makefile
+++ b/drivers/usb/gadget/Makefile
@@ -33,6 +33,8 @@
 					epautoconf.o
 g_printer-objs			:= printer.o usbstring.o config.o \
 					epautoconf.o
+g_cdc-objs			:= cdc2.o u_ether.o f_ecm.o \
+					u_serial.o f_acm.o $(C_UTILS)
 
 ifeq ($(CONFIG_USB_ETH_RNDIS),y)
 	g_ether-objs		+= f_rndis.o rndis.o
@@ -45,4 +47,5 @@
 obj-$(CONFIG_USB_G_SERIAL)	+= g_serial.o
 obj-$(CONFIG_USB_G_PRINTER)	+= g_printer.o
 obj-$(CONFIG_USB_MIDI_GADGET)	+= g_midi.o
+obj-$(CONFIG_USB_CDC_COMPOSITE) += g_cdc.o