staging: usb: gadget: Add Configurable Composite Gadget driver

The Configurable Gadget driver is a composite driver that allows
userspace to change at runtime the list of functions enabled in
its configuration and to configure these functions. It supports
multiple functions: acm, rndis, and mass storage.

It is usually controlled by a daemon that changes the configuration
based on user settings. For example, rndis is enabled when the user
enables sharing the phone data connection.

As an example on how to use it, the following shell commands will
make the gadget disconnect from the host and make it be re-enumerated
as a composite with 1 rndis and 2 acm interfaces, and a different
product id:

echo 0       > /sys/class/ccg_usb/ccg0/enable
echo rndis,acm > /sys/class/ccg_usb/ccg0/functions
echo 2       > /sys/class/ccg_usb/ccg0/f_acm/instances
echo -n 0x2d01 > /sys/module/g_ccg/parameters/idProduct
echo 1       > /sys/class/ccg_usb/ccg0/enable

The driver requires a gadget controller that supports software
control of the D+ pullup and the controller driver must support
disabling the pullup during composite_bind.
Signed-off-by: Mike Lockwood <lockwood@android.com>
Signed-off-by: Benoit Goby <benoit@android.com>
	[import from android.c, implement review comments, remove adb,mtp,ptp,accessory]
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/Kconfig

@@ -130,4 +130,6 @@ source "drivers/staging/ramster/Kconfig"
 
 source "drivers/staging/ozwpan/Kconfig"
 
+source "drivers/staging/ccg/Kconfig"
+
 endif # STAGING

drivers/staging/Makefile

@@ -56,3 +56,4 @@ obj-$(CONFIG_ANDROID)		+= android/
 obj-$(CONFIG_PHONE)		+= telephony/
 obj-$(CONFIG_RAMSTER)		+= ramster/
 obj-$(CONFIG_USB_WPAN_HCD)	+= ozwpan/
+obj-$(CONFIG_USB_G_CCG)		+= ccg/

drivers/staging/ccg/Kconfig

+if USB_GADGET
+
+config USB_G_CCG
+	tristate "Configurable Composite Gadget (STAGING)"
+	depends on STAGING && !USB_ZERO && !USB_ZERO_HNPTEST && !USB_AUDIO && !GADGET_UAC1 && !USB_ETH && !USB_ETH_RNDIS && !USB_ETH_EEM && !USB_G_NCM && !USB_GADGETFS && !USB_FUNCTIONFS && !USB_FUNCTIONFS_ETH && !USB_FUNCTIONFS_RNDIS && !USB_FUNCTIONFS_GENERIC && !USB_FILE_STORAGE && !USB_FILE_STORAGE_TEST && !USB_MASS_STORAGE && !USB_G_SERIAL && !USB_MIDI_GADGET && !USB_G_PRINTER && !USB_CDC_COMPOSITE && !USB_G_NOKIA && !USB_G_ACM_MS && !USB_G_MULTI && !USB_G_MULTI_RNDIS && !USB_G_MULTI_CDC && !USB_G_HID && !USB_G_DBGP && !USB_G_WEBCAM
+	help
+	  The Configurable Composite Gadget supports multiple USB
+	  functions: acm, mass storage, rndis and FunctionFS.
+	  Each function can be configured and enabled/disabled
+	  dynamically from userspace through a sysfs interface.
+
+	  In order to compile this (either as a module or built-in),
+	  "USB Gadget Drivers" and anything under it must not be
+	  selected compiled-in in
+	  Device Drivers->USB Support->USB Gadget Support.
+	  However, you can say "M" there, if you do, the
+	  Configurable Composite Gadget can be compiled "M" only
+	  or not at all.
+
+endif # USB_GADGET

drivers/staging/ccg/Makefile

+g_ccg-y				:= ccg.o
+ccflags-y			+= -Idrivers/usb/gadget
+
+obj-$(CONFIG_USB_G_CCG)		+= g_ccg.o

drivers/staging/ccg/TODO

+TODO:
+	- change configuration interface from sysfs to configfs
+
+Please send patches to Greg Kroah-Hartmann <gregkh@linuxfoundation.org>,
+Andrzej Pietrasiewicz <andrzej.p@samsung.com>, and
+Cc: Mike Lockwood <lockwood@android.com>

drivers/staging/ccg/sysfs-class-ccg_usb

+What:		/sys/class/ccg_usb
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The ccg_usb/ class subdirectory belongs to ccg
+		USB gadget.
+
+What:		/sys/class/ccg_usb/ccgX
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccg{0,1,2,3...} class
+		subdirectories correspond to each ccg gadget device;
+		at the time of this writing there is only ccg0 and it
+		represents the ccg gadget.
+
+What:		/sys/class/ccg_usb/ccgX/functions
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		A comma-separated list of USB function names to be activated
+		in this ccg gadget.
+
+What:		/sys/class/ccg_usb/ccgX/enable
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		A flag activating/deactivating the ccg usb gadget.
+
+What:		/sys/class/ccg_usb/ccgX/state
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		Configurable usb gadget state:
+
+		DISCONNECTED
+		CONNECTED
+		CONFIGURED
+
+What:		/sys/class/ccg_usb/ccgX/f_acm/
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccgX/f_acm subdirectory
+		corresponds to the gadget's USB CDC serial (ACM) function
+		driver.
+
+What:		/sys/class/ccg_usb/ccgX/f_acm/instances
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		Maximum number of the /dev/ttyGS<X> interface the driver uses.
+
+What:		/sys/class/ccg_usb/ccgX/f_rndis
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccgX/f_rndis subdirectory
+		corresponds to the gadget's RNDIS driver.
+
+What:		/sys/class/ccg_usb/ccgX/f_rndis/manufacturer
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		RNDIS Ethernet port manufacturer string.
+
+What:		/sys/class/ccg_usb/ccgX/f_rndis/wceis
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		RNDIS Ethernet port wireless flag.
+
+What:		/sys/class/ccg_usb/ccgX/f_rndis/ethaddr
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		RNDIS Ethernet port Ethernet address.
+
+What:		/sys/class/ccg_usb/ccgX/f_rndis/vendorID
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		RNDIS Ethernet port vendor ID.
+
+What:		/sys/class/ccg_usb/ccgX/f_mass_storage
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccgX/f_mass_storage subdirectory
+		corresponds to the gadget's USB mass storage driver.
+
+What:		/sys/class/ccg_usb/ccgX/f_mass_storage/lun
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccgX/f_mass_storage/lun
+		subdirectory corresponds to the gadget's USB mass storage
+		driver and its underlying storage.
+
+What:		/sys/class/ccg_usb/ccgX/f_mass_storage/lun
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		The /sys/class/ccg_usb/ccgX/f_mass_storage/lun
+		subdirectory corresponds to the gadget's USB mass storage
+		driver and its underlying storage.
+
+What:		/sys/class/ccg_usb/ccgX/f_mass_storage/lun/file
+Date:		May 2012
+KernelVersion:	3.4
+Contact:	linux-usb@vger.kernel.org
+Description:
+		Gadget's USB mass storage underlying file.