usb: gadget: Gadget directory cleanup - group legacy gadgets

The drivers/usb/gadget directory contains many files.
Files which are related can be distributed into separate directories.
This patch moves the legacy gadgets (i.e. those not using configfs)
into a separate directory.

Signed-off-by: Andrzej Pietrasiewicz <[e-mail]>
Signed-off-by: Felipe Balbi <[e-mail]>

drivers/usb/gadget/Kconfig

···
 	  implemented in kernel space (for instance Ethernet, serial or
 	  mass storage) and other are implemented in user space.
 
-config USB_ZERO
-	tristate "Gadget Zero (DEVELOPMENT)"
-	select USB_LIBCOMPOSITE
-	select USB_F_SS_LB
-	help
-	  Gadget Zero is a two-configuration device.  It either sinks and
-	  sources bulk data; or it loops back a configurable number of
-	  transfers.  It also implements control requests, for "chapter 9"
-	  conformance.  The driver needs only two bulk-capable endpoints, so
-	  it can work on top of most device-side usb controllers.  It's
-	  useful for testing, and is also a working example showing how
-	  USB "gadget drivers" can be written.
-
-	  Make this be the first driver you try using on top of any new
-	  USB peripheral controller driver.  Then you can use host-side
-	  test software, like the "usbtest" driver, to put your hardware
-	  and its driver through a basic set of functional tests.
-
-	  Gadget Zero also works with the host-side "usb-skeleton" driver,
-	  and with many kinds of host-side test software.  You may need
-	  to tweak product and vendor IDs before host software knows about
-	  this device, and arrange to select an appropriate configuration.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_zero".
-
-config USB_ZERO_HNPTEST
-	boolean "HNP Test Device"
-	depends on USB_ZERO && USB_OTG
-	help
-	  You can configure this device to enumerate using the device
-	  identifiers of the USB-OTG test device.  That means that when
-	  this gadget connects to another OTG device, with this one using
-	  the "B-Peripheral" role, that device will use HNP to let this
-	  one serve as the USB host instead (in the "B-Host" role).
-
-config USB_AUDIO
-	tristate "Audio Gadget"
-	depends on SND
-	select USB_LIBCOMPOSITE
-	select SND_PCM
-	help
-	  This Gadget Audio driver is compatible with USB Audio Class
-	  specification 2.0. It implements 1 AudioControl interface,
-	  1 AudioStreaming Interface each for USB-OUT and USB-IN.
-	  Number of channels, sample rate and sample size can be
-	  specified as module parameters.
-	  This driver doesn't expect any real Audio codec to be present
-	  on the device - the audio streams are simply sinked to and
-	  sourced from a virtual ALSA sound card created. The user-space
-	  application may choose to do whatever it wants with the data
-	  received from the USB Host and choose to provide whatever it
-	  wants as audio data to the USB Host.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_audio".
-
-config GADGET_UAC1
-	bool "UAC 1.0 (Legacy)"
-	depends on USB_AUDIO
-	help
-	  If you instead want older UAC Spec-1.0 driver that also has audio
-	  paths hardwired to the Audio codec chip on-board and doesn't work
-	  without one.
-
-config USB_ETH
-	tristate "Ethernet Gadget (with CDC Ethernet support)"
-	depends on NET
-	select USB_LIBCOMPOSITE
-	select USB_U_ETHER
-	select USB_F_ECM
-	select USB_F_SUBSET
-	select CRC32
-	help
-	  This driver implements Ethernet style communication, in one of
-	  several ways:
-	  
-	   - The "Communication Device Class" (CDC) Ethernet Control Model.
-	     That protocol is often avoided with pure Ethernet adapters, in
-	     favor of simpler vendor-specific hardware, but is widely
-	     supported by firmware for smart network devices.
-
-	   - On hardware can't implement that protocol, a simple CDC subset
-	     is used, placing fewer demands on USB.
-
-	   - CDC Ethernet Emulation Model (EEM) is a newer standard that has
-	     a simpler interface that can be used by more USB hardware.
-
-	  RNDIS support is an additional option, more demanding than than
-	  subset.
-
-	  Within the USB device, this gadget driver exposes a network device
-	  "usbX", where X depends on what other networking devices you have.
-	  Treat it like a two-node Ethernet link:  host, and gadget.
-
-	  The Linux-USB host-side "usbnet" driver interoperates with this
-	  driver, so that deep I/O queues can be supported.  On 2.4 kernels,
-	  use "CDCEther" instead, if you're using the CDC option. That CDC
-	  mode should also interoperate with standard CDC Ethernet class
-	  drivers on other host operating systems.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_ether".
-
-config USB_ETH_RNDIS
-	bool "RNDIS support"
-	depends on USB_ETH
-	select USB_LIBCOMPOSITE
-	select USB_F_RNDIS
-	default y
-	help
-	   Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
-	   and Microsoft provides redistributable binary RNDIS drivers for
-	   older versions of Windows.
-
-	   If you say "y" here, the Ethernet gadget driver will try to provide
-	   a second device configuration, supporting RNDIS to talk to such
-	   Microsoft USB hosts.
-	   
-	   To make MS-Windows work with this, use Documentation/usb/linux.inf
-	   as the "driver info file".  For versions of MS-Windows older than
-	   XP, you'll need to download drivers from Microsoft's website; a URL
-	   is given in comments found in that info file.
-
-config USB_ETH_EEM
-       bool "Ethernet Emulation Model (EEM) support"
-       depends on USB_ETH
-	select USB_LIBCOMPOSITE
-	select USB_F_EEM
-       default n
-       help
-         CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
-         and therefore can be supported by more hardware.  Technically ECM and
-         EEM are designed for different applications.  The ECM model extends
-         the network interface to the target (e.g. a USB cable modem), and the
-         EEM model is for mobile devices to communicate with hosts using
-         ethernet over USB.  For Linux gadgets, however, the interface with
-         the host is the same (a usbX device), so the differences are minimal.
-
-         If you say "y" here, the Ethernet gadget driver will use the EEM
-         protocol rather than ECM.  If unsure, say "n".
-
-config USB_G_NCM
-	tristate "Network Control Model (NCM) support"
-	depends on NET
-	select USB_LIBCOMPOSITE
-	select USB_U_ETHER
-	select USB_F_NCM
-	select CRC32
-	help
-	  This driver implements USB CDC NCM subclass standard. NCM is
-	  an advanced protocol for Ethernet encapsulation, allows grouping
-	  of several ethernet frames into one USB transfer and different
-	  alignment possibilities.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_ncm".
-
-config USB_GADGETFS
-	tristate "Gadget Filesystem"
-	help
-	  This driver provides a filesystem based API that lets user mode
-	  programs implement a single-configuration USB device, including
-	  endpoint I/O and control requests that don't relate to enumeration.
-	  All endpoints, transfer speeds, and transfer types supported by
-	  the hardware are available, through read() and write() calls.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "gadgetfs".
-
-config USB_FUNCTIONFS
-	tristate "Function Filesystem"
-	select USB_LIBCOMPOSITE
-	select USB_F_FS
-	select USB_FUNCTIONFS_GENERIC if !(USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
-	help
-	  The Function Filesystem (FunctionFS) lets one create USB
-	  composite functions in user space in the same way GadgetFS
-	  lets one create USB gadgets in user space.  This allows creation
-	  of composite gadgets such that some of the functions are
-	  implemented in kernel space (for instance Ethernet, serial or
-	  mass storage) and other are implemented in user space.
-
-	  If you say "y" or "m" here you will be able what kind of
-	  configurations the gadget will provide.
-
-	  Say "y" to link the driver statically, or "m" to build
-	  a dynamically linked module called "g_ffs".
-
-config USB_FUNCTIONFS_ETH
-	bool "Include configuration with CDC ECM (Ethernet)"
-	depends on USB_FUNCTIONFS && NET
-	select USB_U_ETHER
-	select USB_F_ECM
-	select USB_F_SUBSET
-	help
-	  Include a configuration with CDC ECM function (Ethernet) and the
-	  Function Filesystem.
-
-config USB_FUNCTIONFS_RNDIS
-	bool "Include configuration with RNDIS (Ethernet)"
-	depends on USB_FUNCTIONFS && NET
-	select USB_U_ETHER
-	select USB_F_RNDIS
-	help
-	  Include a configuration with RNDIS function (Ethernet) and the Filesystem.
-
-config USB_FUNCTIONFS_GENERIC
-	bool "Include 'pure' configuration"
-	depends on USB_FUNCTIONFS
-	help
-	  Include a configuration with the Function Filesystem alone with
-	  no Ethernet interface.
-
-config USB_MASS_STORAGE
-	tristate "Mass Storage Gadget"
-	depends on BLOCK
-	select USB_LIBCOMPOSITE
-	select USB_F_MASS_STORAGE
-	help
-	  The Mass Storage Gadget acts as a USB Mass Storage disk drive.
-	  As its storage repository it can use a regular file or a block
-	  device (in much the same way as the "loop" device driver),
-	  specified as a module parameter or sysfs option.
-
-	  This driver is a replacement for now removed File-backed
-	  Storage Gadget (g_file_storage).
-
-	  Say "y" to link the driver statically, or "m" to build
-	  a dynamically linked module called "g_mass_storage".
-
-config USB_GADGET_TARGET
-	tristate "USB Gadget Target Fabric Module"
-	depends on TARGET_CORE
-	select USB_LIBCOMPOSITE
-	help
-	  This fabric is an USB gadget. Two USB protocols are supported that is
-	  BBB or BOT (Bulk Only Transport) and UAS (USB Attached SCSI). BOT is
-	  advertised on alternative interface 0 (primary) and UAS is on
-	  alternative interface 1. Both protocols can work on USB2.0 and USB3.0.
-	  UAS utilizes the USB 3.0 feature called streams support.
-
-config USB_G_SERIAL
-	tristate "Serial Gadget (with CDC ACM and CDC OBEX support)"
-	depends on TTY
-	select USB_U_SERIAL
-	select USB_F_ACM
-	select USB_F_SERIAL
-	select USB_F_OBEX
-	select USB_LIBCOMPOSITE
-	help
-	  The Serial Gadget talks to the Linux-USB generic serial driver.
-	  This driver supports a CDC-ACM module option, which can be used
-	  to interoperate with MS-Windows hosts or with the Linux-USB
-	  "cdc-acm" driver.
-
-	  This driver also supports a CDC-OBEX option.  You will need a
-	  user space OBEX server talking to /dev/ttyGS*, since the kernel
-	  itself doesn't implement the OBEX protocol.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_serial".
-
-	  For more information, see Documentation/usb/gadget_serial.txt
-	  which includes instructions and a "driver info file" needed to
-	  make MS-Windows work with CDC ACM.
-
-config USB_MIDI_GADGET
-	tristate "MIDI Gadget"
-	depends on SND
-	select USB_LIBCOMPOSITE
-	select SND_RAWMIDI
-	help
-	  The MIDI Gadget acts as a USB Audio device, with one MIDI
-	  input and one MIDI output. These MIDI jacks appear as
-	  a sound "card" in the ALSA sound system. Other MIDI
-	  connections can then be made on the gadget system, using
-	  ALSA's aconnect utility etc.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_midi".
-
-config USB_G_PRINTER
-	tristate "Printer Gadget"
-	select USB_LIBCOMPOSITE
-	help
-	  The Printer Gadget channels data between the USB host and a
-	  userspace program driving the print engine. The user space
-	  program reads and writes the device file /dev/g_printer to
-	  receive or send printer data. It can use ioctl calls to
-	  the device file to get or set printer status.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_printer".
-
-	  For more information, see Documentation/usb/gadget_printer.txt
-	  which includes sample code for accessing the device file.
-
-if TTY
-
-config USB_CDC_COMPOSITE
-	tristate "CDC Composite Device (Ethernet and ACM)"
-	depends on NET
-	select USB_LIBCOMPOSITE
-	select USB_U_SERIAL
-	select USB_U_ETHER
-	select USB_F_ACM
-	select USB_F_ECM
-	help
-	  This driver provides two functions in one configuration:
-	  a CDC Ethernet (ECM) link, and a CDC ACM (serial port) link.
-
-	  This driver requires four bulk and two interrupt endpoints,
-	  plus the ability to handle altsettings.  Not all peripheral
-	  controllers are that capable.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module.
-
-config USB_G_NOKIA
-	tristate "Nokia composite gadget"
-	depends on PHONET
-	select USB_LIBCOMPOSITE
-	select USB_U_SERIAL
-	select USB_U_ETHER
-	select USB_F_ACM
-	select USB_F_OBEX
-	select USB_F_PHONET
-	select USB_F_ECM
-	help
-	  The Nokia composite gadget provides support for acm, obex
-	  and phonet in only one composite gadget driver.
-
-	  It's only really useful for N900 hardware. If you're building
-	  a kernel for N900, say Y or M here. If unsure, say N.
-
-config USB_G_ACM_MS
-	tristate "CDC Composite Device (ACM and mass storage)"
-	depends on BLOCK
-	select USB_LIBCOMPOSITE
-	select USB_U_SERIAL
-	select USB_F_ACM
-	select USB_F_MASS_STORAGE
-	help
-	  This driver provides two functions in one configuration:
-	  a mass storage, and a CDC ACM (serial port) link.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_acm_ms".
-
-config USB_G_MULTI
-	tristate "Multifunction Composite Gadget"
-	depends on BLOCK && NET
-	select USB_G_MULTI_CDC if !USB_G_MULTI_RNDIS
-	select USB_LIBCOMPOSITE
-	select USB_U_SERIAL
-	select USB_U_ETHER
-	select USB_F_ACM
-	select USB_F_MASS_STORAGE
-	help
-	  The Multifunction Composite Gadget provides Ethernet (RNDIS
-	  and/or CDC Ethernet), mass storage and ACM serial link
-	  interfaces.
-
-	  You will be asked to choose which of the two configurations is
-	  to be available in the gadget.  At least one configuration must
-	  be chosen to make the gadget usable.  Selecting more than one
-	  configuration will prevent Windows from automatically detecting
-	  the gadget as a composite gadget, so an INF file will be needed to
-	  use the gadget.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_multi".
-
-config USB_G_MULTI_RNDIS
-	bool "RNDIS + CDC Serial + Storage configuration"
-	depends on USB_G_MULTI
-	select USB_F_RNDIS
-	default y
-	help
-	  This option enables a configuration with RNDIS, CDC Serial and
-	  Mass Storage functions available in the Multifunction Composite
-	  Gadget.  This is the configuration dedicated for Windows since RNDIS
-	  is Microsoft's protocol.
-
-	  If unsure, say "y".
-
-config USB_G_MULTI_CDC
-	bool "CDC Ethernet + CDC Serial + Storage configuration"
-	depends on USB_G_MULTI
-	default n
-	select USB_F_ECM
-	help
-	  This option enables a configuration with CDC Ethernet (ECM), CDC
-	  Serial and Mass Storage functions available in the Multifunction
-	  Composite Gadget.
-
-	  If unsure, say "y".
-
-endif # TTY
-
-config USB_G_HID
-	tristate "HID Gadget"
-	select USB_LIBCOMPOSITE
-	help
-	  The HID gadget driver provides generic emulation of USB
-	  Human Interface Devices (HID).
-
-	  For more information, see Documentation/usb/gadget_hid.txt which
-	  includes sample code for accessing the device files.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_hid".
-
-# Standalone / single function gadgets
-config USB_G_DBGP
-	tristate "EHCI Debug Device Gadget"
-	depends on TTY
-	select USB_LIBCOMPOSITE
-	help
-	  This gadget emulates an EHCI Debug device. This is useful when you want
-	  to interact with an EHCI Debug Port.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_dbgp".
-
-if USB_G_DBGP
-choice
-	prompt "EHCI Debug Device mode"
-	default USB_G_DBGP_SERIAL
-
-config USB_G_DBGP_PRINTK
-	depends on USB_G_DBGP
-	bool "printk"
-	help
-	  Directly printk() received data. No interaction.
-
-config USB_G_DBGP_SERIAL
-	depends on USB_G_DBGP
-	select USB_U_SERIAL
-	bool "serial"
-	help
-	  Userland can interact using /dev/ttyGSxxx.
-endchoice
-endif
-
-# put drivers that need isochronous transfer support (for audio
-# or video class gadget drivers), or specific hardware, here.
-config USB_G_WEBCAM
-	tristate "USB Webcam Gadget"
-	depends on VIDEO_DEV
-	select USB_LIBCOMPOSITE
-	select VIDEOBUF2_VMALLOC
-	help
-	  The Webcam Gadget acts as a composite USB Audio and Video Class
-	  device. It provides a userspace API to process UVC control requests
-	  and stream video data to the host.
-
-	  Say "y" to link the driver statically, or "m" to build a
-	  dynamically linked module called "g_webcam".
+source "drivers/usb/gadget/legacy/Kconfig"
 
 endchoice
 

drivers/usb/gadget/Makefile

···
 #
 # USB peripheral controller drivers
 #
-ccflags-$(CONFIG_USB_GADGET_DEBUG)	:= -DDEBUG
-ccflags-$(CONFIG_USB_GADGET_VERBOSE)	+= -DVERBOSE_DEBUG
+subdir-ccflags-$(CONFIG_USB_GADGET_DEBUG)	:= -DDEBUG
+subdir-ccflags-$(CONFIG_USB_GADGET_VERBOSE)	+= -DVERBOSE_DEBUG
 
 obj-$(CONFIG_USB_GADGET)	+= udc-core.o
 obj-$(CONFIG_USB_LIBCOMPOSITE)	+= libcomposite.o
···
 usb_f_fs-y			:= f_fs.o
 obj-$(CONFIG_USB_F_FS)		+= usb_f_fs.o
 
-#
-# USB gadget drivers
-#
-g_zero-y			:= zero.o
-g_audio-y			:= audio.o
-g_ether-y			:= ether.o
-g_serial-y			:= serial.o
-g_midi-y			:= gmidi.o
-gadgetfs-y			:= inode.o
-g_mass_storage-y		:= mass_storage.o
-g_printer-y			:= printer.o
-g_cdc-y				:= cdc2.o
-g_multi-y			:= multi.o
-g_hid-y				:= hid.o
-g_dbgp-y			:= dbgp.o
-g_nokia-y			:= nokia.o
-g_webcam-y			:= webcam.o
-g_ncm-y				:= ncm.o
-g_acm_ms-y			:= acm_ms.o
-g_tcm_usb_gadget-y		:= tcm_usb_gadget.o
-
-obj-$(CONFIG_USB_ZERO)		+= g_zero.o
-obj-$(CONFIG_USB_AUDIO)		+= g_audio.o
-obj-$(CONFIG_USB_ETH)		+= g_ether.o
-obj-$(CONFIG_USB_GADGETFS)	+= gadgetfs.o
-obj-$(CONFIG_USB_FUNCTIONFS)	+= g_ffs.o
-obj-$(CONFIG_USB_MASS_STORAGE)	+= g_mass_storage.o
-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
-obj-$(CONFIG_USB_G_HID)		+= g_hid.o
-obj-$(CONFIG_USB_G_DBGP)	+= g_dbgp.o
-obj-$(CONFIG_USB_G_MULTI)	+= g_multi.o
-obj-$(CONFIG_USB_G_NOKIA)	+= g_nokia.o
-obj-$(CONFIG_USB_G_WEBCAM)	+= g_webcam.o
-obj-$(CONFIG_USB_G_NCM)		+= g_ncm.o
-obj-$(CONFIG_USB_G_ACM_MS)	+= g_acm_ms.o
-obj-$(CONFIG_USB_GADGET_TARGET)	+= tcm_usb_gadget.o
+obj-$(CONFIG_USB_GADGET)	+= legacy/

drivers/usb/gadget/legacy/Kconfig

···
+#
+# USB Gadget support on a system involves
+#    (a) a peripheral controller, and
+#    (b) the gadget driver using it.
+#
+# NOTE:  Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
+#
+#  - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
+#  - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
+#  - Some systems have both kinds of controllers.
+#
+# With help from a special transceiver and a "Mini-AB" jack, systems with
+# both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
+#
+
+config USB_ZERO
+	tristate "Gadget Zero (DEVELOPMENT)"
+	select USB_LIBCOMPOSITE
+	select USB_F_SS_LB
+	help
+	  Gadget Zero is a two-configuration device.  It either sinks and
+	  sources bulk data; or it loops back a configurable number of
+	  transfers.  It also implements control requests, for "chapter 9"
+	  conformance.  The driver needs only two bulk-capable endpoints, so
+	  it can work on top of most device-side usb controllers.  It's
+	  useful for testing, and is also a working example showing how
+	  USB "gadget drivers" can be written.
+
+	  Make this be the first driver you try using on top of any new
+	  USB peripheral controller driver.  Then you can use host-side
+	  test software, like the "usbtest" driver, to put your hardware
+	  and its driver through a basic set of functional tests.
+
+	  Gadget Zero also works with the host-side "usb-skeleton" driver,
+	  and with many kinds of host-side test software.  You may need
+	  to tweak product and vendor IDs before host software knows about
+	  this device, and arrange to select an appropriate configuration.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_zero".
+
+config USB_ZERO_HNPTEST
+	boolean "HNP Test Device"
+	depends on USB_ZERO && USB_OTG
+	help
+	  You can configure this device to enumerate using the device
+	  identifiers of the USB-OTG test device.  That means that when
+	  this gadget connects to another OTG device, with this one using
+	  the "B-Peripheral" role, that device will use HNP to let this
+	  one serve as the USB host instead (in the "B-Host" role).
+
+config USB_AUDIO
+	tristate "Audio Gadget"
+	depends on SND
+	select USB_LIBCOMPOSITE
+	select SND_PCM
+	help
+	  This Gadget Audio driver is compatible with USB Audio Class
+	  specification 2.0. It implements 1 AudioControl interface,
+	  1 AudioStreaming Interface each for USB-OUT and USB-IN.
+	  Number of channels, sample rate and sample size can be
+	  specified as module parameters.
+	  This driver doesn't expect any real Audio codec to be present
+	  on the device - the audio streams are simply sinked to and
+	  sourced from a virtual ALSA sound card created. The user-space
+	  application may choose to do whatever it wants with the data
+	  received from the USB Host and choose to provide whatever it
+	  wants as audio data to the USB Host.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_audio".
+
+config GADGET_UAC1
+	bool "UAC 1.0 (Legacy)"
+	depends on USB_AUDIO
+	help
+	  If you instead want older UAC Spec-1.0 driver that also has audio
+	  paths hardwired to the Audio codec chip on-board and doesn't work
+	  without one.
+
+config USB_ETH
+	tristate "Ethernet Gadget (with CDC Ethernet support)"
+	depends on NET
+	select USB_LIBCOMPOSITE
+	select USB_U_ETHER
+	select USB_F_ECM
+	select USB_F_SUBSET
+	select CRC32
+	help
+	  This driver implements Ethernet style communication, in one of
+	  several ways:
+
+	   - The "Communication Device Class" (CDC) Ethernet Control Model.
+	     That protocol is often avoided with pure Ethernet adapters, in
+	     favor of simpler vendor-specific hardware, but is widely
+	     supported by firmware for smart network devices.
+
+	   - On hardware can't implement that protocol, a simple CDC subset
+	     is used, placing fewer demands on USB.
+
+	   - CDC Ethernet Emulation Model (EEM) is a newer standard that has
+	     a simpler interface that can be used by more USB hardware.
+
+	  RNDIS support is an additional option, more demanding than than
+	  subset.
+
+	  Within the USB device, this gadget driver exposes a network device
+	  "usbX", where X depends on what other networking devices you have.
+	  Treat it like a two-node Ethernet link:  host, and gadget.
+
+	  The Linux-USB host-side "usbnet" driver interoperates with this
+	  driver, so that deep I/O queues can be supported.  On 2.4 kernels,
+	  use "CDCEther" instead, if you're using the CDC option. That CDC
+	  mode should also interoperate with standard CDC Ethernet class
+	  drivers on other host operating systems.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_ether".
+
+config USB_ETH_RNDIS
+	bool "RNDIS support"
+	depends on USB_ETH
+	select USB_LIBCOMPOSITE
+	select USB_F_RNDIS
+	default y
+	help
+	   Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
+	   and Microsoft provides redistributable binary RNDIS drivers for
+	   older versions of Windows.
+
+	   If you say "y" here, the Ethernet gadget driver will try to provide
+	   a second device configuration, supporting RNDIS to talk to such
+	   Microsoft USB hosts.
+
+	   To make MS-Windows work with this, use Documentation/usb/linux.inf
+	   as the "driver info file".  For versions of MS-Windows older than
+	   XP, you'll need to download drivers from Microsoft's website; a URL
+	   is given in comments found in that info file.
+
+config USB_ETH_EEM
+       bool "Ethernet Emulation Model (EEM) support"
+       depends on USB_ETH
+	select USB_LIBCOMPOSITE
+	select USB_F_EEM
+       default n
+       help
+         CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
+         and therefore can be supported by more hardware.  Technically ECM and
+         EEM are designed for different applications.  The ECM model extends
+         the network interface to the target (e.g. a USB cable modem), and the
+         EEM model is for mobile devices to communicate with hosts using
+         ethernet over USB.  For Linux gadgets, however, the interface with
+         the host is the same (a usbX device), so the differences are minimal.
+
+         If you say "y" here, the Ethernet gadget driver will use the EEM
+         protocol rather than ECM.  If unsure, say "n".
+
+config USB_G_NCM
+	tristate "Network Control Model (NCM) support"
+	depends on NET
+	select USB_LIBCOMPOSITE
+	select USB_U_ETHER
+	select USB_F_NCM
+	select CRC32
+	help
+	  This driver implements USB CDC NCM subclass standard. NCM is
+	  an advanced protocol for Ethernet encapsulation, allows grouping
+	  of several ethernet frames into one USB transfer and different
+	  alignment possibilities.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_ncm".
+
+config USB_GADGETFS
+	tristate "Gadget Filesystem"
+	help
+	  This driver provides a filesystem based API that lets user mode
+	  programs implement a single-configuration USB device, including
+	  endpoint I/O and control requests that don't relate to enumeration.
+	  All endpoints, transfer speeds, and transfer types supported by
+	  the hardware are available, through read() and write() calls.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "gadgetfs".
+
+config USB_FUNCTIONFS
+	tristate "Function Filesystem"
+	select USB_LIBCOMPOSITE
+	select USB_F_FS
+	select USB_FUNCTIONFS_GENERIC if !(USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
+	help
+	  The Function Filesystem (FunctionFS) lets one create USB
+	  composite functions in user space in the same way GadgetFS
+	  lets one create USB gadgets in user space.  This allows creation
+	  of composite gadgets such that some of the functions are
+	  implemented in kernel space (for instance Ethernet, serial or
+	  mass storage) and other are implemented in user space.
+
+	  If you say "y" or "m" here you will be able what kind of
+	  configurations the gadget will provide.
+
+	  Say "y" to link the driver statically, or "m" to build
+	  a dynamically linked module called "g_ffs".
+
+config USB_FUNCTIONFS_ETH
+	bool "Include configuration with CDC ECM (Ethernet)"
+	depends on USB_FUNCTIONFS && NET
+	select USB_U_ETHER
+	select USB_F_ECM
+	select USB_F_SUBSET
+	help
+	  Include a configuration with CDC ECM function (Ethernet) and the
+	  Function Filesystem.
+
+config USB_FUNCTIONFS_RNDIS
+	bool "Include configuration with RNDIS (Ethernet)"
+	depends on USB_FUNCTIONFS && NET
+	select USB_U_ETHER
+	select USB_F_RNDIS
+	help
+	  Include a configuration with RNDIS function (Ethernet) and the Filesystem.
+
+config USB_FUNCTIONFS_GENERIC
+	bool "Include 'pure' configuration"
+	depends on USB_FUNCTIONFS
+	help
+	  Include a configuration with the Function Filesystem alone with
+	  no Ethernet interface.
+
+config USB_MASS_STORAGE
+	tristate "Mass Storage Gadget"
+	depends on BLOCK
+	select USB_LIBCOMPOSITE
+	select USB_F_MASS_STORAGE
+	help
+	  The Mass Storage Gadget acts as a USB Mass Storage disk drive.
+	  As its storage repository it can use a regular file or a block
+	  device (in much the same way as the "loop" device driver),
+	  specified as a module parameter or sysfs option.
+
+	  This driver is a replacement for now removed File-backed
+	  Storage Gadget (g_file_storage).
+
+	  Say "y" to link the driver statically, or "m" to build
+	  a dynamically linked module called "g_mass_storage".
+
+config USB_GADGET_TARGET
+	tristate "USB Gadget Target Fabric Module"
+	depends on TARGET_CORE
+	select USB_LIBCOMPOSITE
+	help
+	  This fabric is an USB gadget. Two USB protocols are supported that is
+	  BBB or BOT (Bulk Only Transport) and UAS (USB Attached SCSI). BOT is
+	  advertised on alternative interface 0 (primary) and UAS is on
+	  alternative interface 1. Both protocols can work on USB2.0 and USB3.0.
+	  UAS utilizes the USB 3.0 feature called streams support.
+
+config USB_G_SERIAL
+	tristate "Serial Gadget (with CDC ACM and CDC OBEX support)"
+	depends on TTY
+	select USB_U_SERIAL
+	select USB_F_ACM
+	select USB_F_SERIAL
+	select USB_F_OBEX
+	select USB_LIBCOMPOSITE
+	help
+	  The Serial Gadget talks to the Linux-USB generic serial driver.
+	  This driver supports a CDC-ACM module option, which can be used
+	  to interoperate with MS-Windows hosts or with the Linux-USB
+	  "cdc-acm" driver.
+
+	  This driver also supports a CDC-OBEX option.  You will need a
+	  user space OBEX server talking to /dev/ttyGS*, since the kernel
+	  itself doesn't implement the OBEX protocol.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_serial".
+
+	  For more information, see Documentation/usb/gadget_serial.txt
+	  which includes instructions and a "driver info file" needed to
+	  make MS-Windows work with CDC ACM.
+
+config USB_MIDI_GADGET
+	tristate "MIDI Gadget"
+	depends on SND
+	select USB_LIBCOMPOSITE
+	select SND_RAWMIDI
+	help
+	  The MIDI Gadget acts as a USB Audio device, with one MIDI
+	  input and one MIDI output. These MIDI jacks appear as
+	  a sound "card" in the ALSA sound system. Other MIDI
+	  connections can then be made on the gadget system, using
+	  ALSA's aconnect utility etc.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_midi".
+
+config USB_G_PRINTER
+	tristate "Printer Gadget"
+	select USB_LIBCOMPOSITE
+	help
+	  The Printer Gadget channels data between the USB host and a
+	  userspace program driving the print engine. The user space
+	  program reads and writes the device file /dev/g_printer to
+	  receive or send printer data. It can use ioctl calls to
+	  the device file to get or set printer status.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_printer".
+
+	  For more information, see Documentation/usb/gadget_printer.txt
+	  which includes sample code for accessing the device file.
+
+if TTY
+
+config USB_CDC_COMPOSITE
+	tristate "CDC Composite Device (Ethernet and ACM)"
+	depends on NET
+	select USB_LIBCOMPOSITE
+	select USB_U_SERIAL
+	select USB_U_ETHER
+	select USB_F_ACM
+	select USB_F_ECM
+	help
+	  This driver provides two functions in one configuration:
+	  a CDC Ethernet (ECM) link, and a CDC ACM (serial port) link.
+
+	  This driver requires four bulk and two interrupt endpoints,
+	  plus the ability to handle altsettings.  Not all peripheral
+	  controllers are that capable.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module.
+
+config USB_G_NOKIA
+	tristate "Nokia composite gadget"
+	depends on PHONET
+	select USB_LIBCOMPOSITE
+	select USB_U_SERIAL
+	select USB_U_ETHER
+	select USB_F_ACM
+	select USB_F_OBEX
+	select USB_F_PHONET
+	select USB_F_ECM
+	help
+	  The Nokia composite gadget provides support for acm, obex
+	  and phonet in only one composite gadget driver.
+
+	  It's only really useful for N900 hardware. If you're building
+	  a kernel for N900, say Y or M here. If unsure, say N.
+
+config USB_G_ACM_MS
+	tristate "CDC Composite Device (ACM and mass storage)"
+	depends on BLOCK
+	select USB_LIBCOMPOSITE
+	select USB_U_SERIAL
+	select USB_F_ACM
+	select USB_F_MASS_STORAGE
+	help
+	  This driver provides two functions in one configuration:
+	  a mass storage, and a CDC ACM (serial port) link.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_acm_ms".
+
+config USB_G_MULTI
+	tristate "Multifunction Composite Gadget"
+	depends on BLOCK && NET
+	select USB_G_MULTI_CDC if !USB_G_MULTI_RNDIS
+	select USB_LIBCOMPOSITE
+	select USB_U_SERIAL
+	select USB_U_ETHER
+	select USB_F_ACM
+	select USB_F_MASS_STORAGE
+	help
+	  The Multifunction Composite Gadget provides Ethernet (RNDIS
+	  and/or CDC Ethernet), mass storage and ACM serial link
+	  interfaces.
+
+	  You will be asked to choose which of the two configurations is
+	  to be available in the gadget.  At least one configuration must
+	  be chosen to make the gadget usable.  Selecting more than one
+	  configuration will prevent Windows from automatically detecting
+	  the gadget as a composite gadget, so an INF file will be needed to
+	  use the gadget.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_multi".
+
+config USB_G_MULTI_RNDIS
+	bool "RNDIS + CDC Serial + Storage configuration"
+	depends on USB_G_MULTI
+	select USB_F_RNDIS
+	default y
+	help
+	  This option enables a configuration with RNDIS, CDC Serial and
+	  Mass Storage functions available in the Multifunction Composite
+	  Gadget.  This is the configuration dedicated for Windows since RNDIS
+	  is Microsoft's protocol.
+
+	  If unsure, say "y".
+
+config USB_G_MULTI_CDC
+	bool "CDC Ethernet + CDC Serial + Storage configuration"
+	depends on USB_G_MULTI
+	default n
+	select USB_F_ECM
+	help
+	  This option enables a configuration with CDC Ethernet (ECM), CDC
+	  Serial and Mass Storage functions available in the Multifunction
+	  Composite Gadget.
+
+	  If unsure, say "y".
+
+endif # TTY
+
+config USB_G_HID
+	tristate "HID Gadget"
+	select USB_LIBCOMPOSITE
+	help
+	  The HID gadget driver provides generic emulation of USB
+	  Human Interface Devices (HID).
+
+	  For more information, see Documentation/usb/gadget_hid.txt which
+	  includes sample code for accessing the device files.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_hid".
+
+# Standalone / single function gadgets
+config USB_G_DBGP
+	tristate "EHCI Debug Device Gadget"
+	depends on TTY
+	select USB_LIBCOMPOSITE
+	help
+	  This gadget emulates an EHCI Debug device. This is useful when you want
+	  to interact with an EHCI Debug Port.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_dbgp".
+
+if USB_G_DBGP
+choice
+	prompt "EHCI Debug Device mode"
+	default USB_G_DBGP_SERIAL
+
+config USB_G_DBGP_PRINTK
+	depends on USB_G_DBGP
+	bool "printk"
+	help
+	  Directly printk() received data. No interaction.
+
+config USB_G_DBGP_SERIAL
+	depends on USB_G_DBGP
+	select USB_U_SERIAL
+	bool "serial"
+	help
+	  Userland can interact using /dev/ttyGSxxx.
+endchoice
+endif
+
+# put drivers that need isochronous transfer support (for audio
+# or video class gadget drivers), or specific hardware, here.
+config USB_G_WEBCAM
+	tristate "USB Webcam Gadget"
+	depends on VIDEO_DEV
+	select USB_LIBCOMPOSITE
+	select VIDEOBUF2_VMALLOC
+	help
+	  The Webcam Gadget acts as a composite USB Audio and Video Class
+	  device. It provides a userspace API to process UVC control requests
+	  and stream video data to the host.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_webcam".

drivers/usb/gadget/legacy/Makefile

···
+#
+# USB gadget drivers
+#
+
+ccflags-y			:= -I$(PWD)/drivers/usb/gadget/
+
+g_zero-y			:= zero.o
+g_audio-y			:= audio.o
+g_ether-y			:= ether.o
+g_serial-y			:= serial.o
+g_midi-y			:= gmidi.o
+gadgetfs-y			:= inode.o
+g_mass_storage-y		:= mass_storage.o
+g_printer-y			:= printer.o
+g_cdc-y				:= cdc2.o
+g_multi-y			:= multi.o
+g_hid-y				:= hid.o
+g_dbgp-y			:= dbgp.o
+g_nokia-y			:= nokia.o
+g_webcam-y			:= webcam.o
+g_ncm-y				:= ncm.o
+g_acm_ms-y			:= acm_ms.o
+g_tcm_usb_gadget-y		:= tcm_usb_gadget.o
+
+obj-$(CONFIG_USB_ZERO)		+= g_zero.o
+obj-$(CONFIG_USB_AUDIO)		+= g_audio.o
+obj-$(CONFIG_USB_ETH)		+= g_ether.o
+obj-$(CONFIG_USB_GADGETFS)	+= gadgetfs.o
+obj-$(CONFIG_USB_FUNCTIONFS)	+= g_ffs.o
+obj-$(CONFIG_USB_MASS_STORAGE)	+= g_mass_storage.o
+obj-$(CONFIG_USB_G_SERIAL)	+= g_serial.o
+obj-$(CONFIG_USB_G_PRINTER)	+= g_printer.o
+obj-$(CONFIG_USB_MIDI_GADGET)	+= g_midi.o
+obj-$(CONFIG_USB_CDC_COMPOSITE) += g_cdc.o
+obj-$(CONFIG_USB_G_HID)		+= g_hid.o
+obj-$(CONFIG_USB_G_DBGP)	+= g_dbgp.o
+obj-$(CONFIG_USB_G_MULTI)	+= g_multi.o
+obj-$(CONFIG_USB_G_NOKIA)	+= g_nokia.o
+obj-$(CONFIG_USB_G_WEBCAM)	+= g_webcam.o
+obj-$(CONFIG_USB_G_NCM)		+= g_ncm.o
+obj-$(CONFIG_USB_G_ACM_MS)	+= g_acm_ms.o
+obj-$(CONFIG_USB_GADGET_TARGET)	+= tcm_usb_gadget.o