1 # SPDX-License-Identifier: GPL-2.0
3 # USB Gadget support on a system involves
4 # (a) a peripheral controller, and
5 # (b) the gadget driver using it.
7 # NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
9 # - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
10 # - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
11 # - Some systems have both kinds of controllers.
13 # With help from a special transceiver and a "Mini-AB" jack, systems with
14 # both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
18 tristate "USB Gadget Support"
22 USB is a host/device protocol, organized with one host (such as a
23 PC) controlling up to 127 peripheral devices.
24 The USB hardware is asymmetric, which makes it easier to set up:
25 you can't connect a "to-the-host" connector to a peripheral.
27 Linux can run in the host, or in the peripheral. In both cases
28 you need a low level bus controller driver, and some software
29 talking to it. Peripheral controllers are often discrete silicon,
30 or are integrated with the CPU in a microcontroller. The more
31 familiar host side controllers have names like "EHCI", "OHCI",
32 or "UHCI", and are usually integrated into southbridges on PC
35 Enable this configuration option if you want to run Linux inside
36 a USB peripheral device. Configure one hardware driver for your
37 peripheral/device side bus controller, and a "gadget driver" for
38 your peripheral protocol. (If you use modular gadget drivers,
39 you may configure more than one.)
41 If in doubt, say "N" and don't enable these drivers; most people
42 don't have this kind of hardware (except maybe inside Linux PDAs).
44 For more information, see <http://www.linux-usb.org/gadget> and
45 the kernel documentation for this API.
49 config USB_GADGET_DEBUG
50 bool "Debugging messages (DEVELOPMENT)"
51 depends on DEBUG_KERNEL
53 Many controller and gadget drivers will print some debugging
54 messages if you use this option to ask for those messages.
56 Avoid enabling these messages, even if you're actively
57 debugging such a driver. Many drivers will emit so many
58 messages that the driver timings are affected, which will
59 either create new failure modes or remove the one you're
60 trying to track down. Never enable these messages for a
63 config USB_GADGET_VERBOSE
64 bool "Verbose debugging Messages (DEVELOPMENT)"
65 depends on USB_GADGET_DEBUG
67 Many controller and gadget drivers will print verbose debugging
68 messages if you use this option to ask for those messages.
70 Avoid enabling these messages, even if you're actively
71 debugging such a driver. Many drivers will emit so many
72 messages that the driver timings are affected, which will
73 either create new failure modes or remove the one you're
74 trying to track down. Never enable these messages for a
77 config USB_GADGET_DEBUG_FILES
78 bool "Debugging information files (DEVELOPMENT)"
81 Some of the drivers in the "gadget" framework can expose
82 debugging information in files such as /proc/driver/udc
83 (for a peripheral controller). The information in these
84 files may help when you're troubleshooting or bringing up a
85 driver on a new board. Enable these files by choosing "Y"
86 here. If in doubt, or to conserve kernel memory, say "N".
88 config USB_GADGET_DEBUG_FS
89 bool "Debugging information files in debugfs (DEVELOPMENT)"
92 Some of the drivers in the "gadget" framework can expose
93 debugging information in files under /sys/kernel/debug/.
94 The information in these files may help when you're
95 troubleshooting or bringing up a driver on a new board.
96 Enable these files by choosing "Y" here. If in doubt, or
97 to conserve kernel memory, say "N".
99 config USB_GADGET_VBUS_DRAW
100 int "Maximum VBUS Power usage (2-500 mA)"
104 Some devices need to draw power from USB when they are
105 configured, perhaps to operate circuitry or to recharge
106 batteries. This is in addition to any local power supply,
107 such as an AC adapter or batteries.
109 Enter the maximum power your device draws through USB, in
110 milliAmperes. The permitted range of values is 2 - 500 mA;
111 0 mA would be legal, but can make some hosts misbehave.
113 This value will be used except for system-specific gadget
114 drivers that have more specific information.
116 config USB_GADGET_STORAGE_NUM_BUFFERS
117 int "Number of storage pipeline buffers"
121 Usually 2 buffers are enough to establish a good buffering
122 pipeline. The number may be increased in order to compensate
123 for a bursty VFS behaviour. For instance there may be CPU wake up
124 latencies that makes the VFS to appear bursty in a system with
125 an CPU on-demand governor. Especially if DMA is doing IO to
126 offload the CPU. In this case the CPU will go into power
127 save often and spin up occasionally to move data within VFS.
128 If selecting USB_GADGET_DEBUG_FILES this value may be set by
129 a module parameter as well.
132 config U_SERIAL_CONSOLE
133 bool "Serial gadget console support"
134 depends on USB_U_SERIAL
136 It supports the serial gadget can be used as a console.
138 source "drivers/usb/gadget/udc/Kconfig"
144 # composite based drivers
145 config USB_LIBCOMPOSITE
148 depends on USB_GADGET
189 config USB_F_MASS_STORAGE
198 config USB_F_UAC1_LEGACY
220 # this first set of drivers all depend on bulk-capable hardware.
223 tristate "USB Gadget functions configurable through configfs"
224 select USB_LIBCOMPOSITE
226 A Linux USB "gadget" can be set up through configfs.
227 If this is the case, the USB functions (which from the host's
228 perspective are seen as interfaces) and configurations are
229 specified simply by creating appropriate directories in configfs.
230 Associating functions with configurations is done by creating
231 appropriate symbolic links.
232 For more information see Documentation/usb/gadget_configfs.rst.
234 config USB_CONFIGFS_SERIAL
235 bool "Generic serial bulk in/out"
236 depends on USB_CONFIGFS
241 The function talks to the Linux-USB generic serial driver.
243 config USB_CONFIGFS_ACM
244 bool "Abstract Control Model (CDC ACM)"
245 depends on USB_CONFIGFS
250 ACM serial link. This function can be used to interoperate with
251 MS-Windows hosts or with the Linux-USB "cdc-acm" driver.
253 config USB_CONFIGFS_OBEX
254 bool "Object Exchange Model (CDC OBEX)"
255 depends on USB_CONFIGFS
260 You will need a user space OBEX server talking to /dev/ttyGS*,
261 since the kernel itself doesn't implement the OBEX protocol.
263 config USB_CONFIGFS_NCM
264 bool "Network Control Model (CDC NCM)"
265 depends on USB_CONFIGFS
271 NCM is an advanced protocol for Ethernet encapsulation, allows
272 grouping of several ethernet frames into one USB transfer and
273 different alignment possibilities.
275 config USB_CONFIGFS_ECM
276 bool "Ethernet Control Model (CDC ECM)"
277 depends on USB_CONFIGFS
282 The "Communication Device Class" (CDC) Ethernet Control Model.
283 That protocol is often avoided with pure Ethernet adapters, in
284 favor of simpler vendor-specific hardware, but is widely
285 supported by firmware for smart network devices.
287 config USB_CONFIGFS_ECM_SUBSET
288 bool "Ethernet Control Model (CDC ECM) subset"
289 depends on USB_CONFIGFS
294 On hardware that can't implement the full protocol,
295 a simple CDC subset is used, placing fewer demands on USB.
297 config USB_CONFIGFS_RNDIS
299 depends on USB_CONFIGFS
304 Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
305 and Microsoft provides redistributable binary RNDIS drivers for
306 older versions of Windows.
308 To make MS-Windows work with this, use Documentation/usb/linux.inf
309 as the "driver info file". For versions of MS-Windows older than
310 XP, you'll need to download drivers from Microsoft's website; a URL
311 is given in comments found in that info file.
313 config USB_CONFIGFS_EEM
314 bool "Ethernet Emulation Model (EEM)"
315 depends on USB_CONFIGFS
321 CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
322 and therefore can be supported by more hardware. Technically ECM and
323 EEM are designed for different applications. The ECM model extends
324 the network interface to the target (e.g. a USB cable modem), and the
325 EEM model is for mobile devices to communicate with hosts using
326 ethernet over USB. For Linux gadgets, however, the interface with
327 the host is the same (a usbX device), so the differences are minimal.
329 config USB_CONFIGFS_PHONET
330 bool "Phonet protocol"
331 depends on USB_CONFIGFS
337 The Phonet protocol implementation for USB device.
339 config USB_CONFIGFS_MASS_STORAGE
341 depends on USB_CONFIGFS
343 select USB_F_MASS_STORAGE
345 The Mass Storage Gadget acts as a USB Mass Storage disk drive.
346 As its storage repository it can use a regular file or a block
347 device (in much the same way as the "loop" device driver),
348 specified as a module parameter or sysfs option.
350 config USB_CONFIGFS_F_LB_SS
351 bool "Loopback and sourcesink function (for testing)"
352 depends on USB_CONFIGFS
355 Loopback function loops back a configurable number of transfers.
356 Sourcesink function either sinks and sources bulk data.
357 It also implements control requests, for "chapter 9" conformance.
358 Make this be the first driver you try using on top of any new
359 USB peripheral controller driver. Then you can use host-side
360 test software, like the "usbtest" driver, to put your hardware
361 and its driver through a basic set of functional tests.
363 config USB_CONFIGFS_F_FS
364 bool "Function filesystem (FunctionFS)"
365 depends on USB_CONFIGFS
368 The Function Filesystem (FunctionFS) lets one create USB
369 composite functions in user space in the same way GadgetFS
370 lets one create USB gadgets in user space. This allows creation
371 of composite gadgets such that some of the functions are
372 implemented in kernel space (for instance Ethernet, serial or
373 mass storage) and other are implemented in user space.
375 config USB_CONFIGFS_F_UAC1
376 bool "Audio Class 1.0"
377 depends on USB_CONFIGFS
379 select USB_LIBCOMPOSITE
384 This Audio function implements 1 AudioControl interface,
385 1 AudioStreaming Interface each for USB-OUT and USB-IN.
386 This driver doesn't expect any real Audio codec to be present
387 on the device - the audio streams are simply sinked to and
388 sourced from a virtual ALSA sound card created. The user-space
389 application may choose to do whatever it wants with the data
390 received from the USB Host and choose to provide whatever it
391 wants as audio data to the USB Host.
393 config USB_CONFIGFS_F_UAC1_LEGACY
394 bool "Audio Class 1.0 (legacy implementation)"
395 depends on USB_CONFIGFS
397 select USB_LIBCOMPOSITE
399 select USB_F_UAC1_LEGACY
401 This Audio function implements 1 AudioControl interface,
402 1 AudioStreaming Interface each for USB-OUT and USB-IN.
403 This is a legacy driver and requires a real Audio codec
404 to be present on the device.
406 config USB_CONFIGFS_F_UAC2
407 bool "Audio Class 2.0"
408 depends on USB_CONFIGFS
410 select USB_LIBCOMPOSITE
415 This Audio function is compatible with USB Audio Class
416 specification 2.0. It implements 1 AudioControl interface,
417 1 AudioStreaming Interface each for USB-OUT and USB-IN.
418 This driver doesn't expect any real Audio codec to be present
419 on the device - the audio streams are simply sinked to and
420 sourced from a virtual ALSA sound card created. The user-space
421 application may choose to do whatever it wants with the data
422 received from the USB Host and choose to provide whatever it
423 wants as audio data to the USB Host.
425 config USB_CONFIGFS_F_MIDI
427 depends on USB_CONFIGFS
429 select USB_LIBCOMPOSITE
433 The MIDI Function acts as a USB Audio device, with one MIDI
434 input and one MIDI output. These MIDI jacks appear as
435 a sound "card" in the ALSA sound system. Other MIDI
436 connections can then be made on the gadget system, using
437 ALSA's aconnect utility etc.
439 config USB_CONFIGFS_F_HID
441 depends on USB_CONFIGFS
444 The HID function driver provides generic emulation of USB
445 Human Interface Devices (HID).
447 For more information, see Documentation/usb/gadget_hid.rst.
449 config USB_CONFIGFS_F_UVC
450 bool "USB Webcam function"
451 depends on USB_CONFIGFS
454 select VIDEOBUF2_DMA_SG
455 select VIDEOBUF2_VMALLOC
458 The Webcam function acts as a composite USB Audio and Video Class
459 device. It provides a userspace API to process UVC control requests
460 and stream video data to the host.
462 config USB_CONFIGFS_F_PRINTER
463 bool "Printer function"
465 depends on USB_CONFIGFS
467 The Printer function channels data between the USB host and a
468 userspace program driving the print engine. The user space
469 program reads and writes the device file /dev/g_printer<X> to
470 receive or send printer data. It can use ioctl calls to
471 the device file to get or set printer status.
473 For more information, see Documentation/usb/gadget_printer.rst
474 which includes sample code for accessing the device file.
476 config USB_CONFIGFS_F_TCM
477 bool "USB Gadget Target Fabric"
478 depends on TARGET_CORE
479 depends on USB_CONFIGFS
480 select USB_LIBCOMPOSITE
483 This fabric is a USB gadget component. Two USB protocols are
484 supported that is BBB or BOT (Bulk Only Transport) and UAS
485 (USB Attached SCSI). BOT is advertised on alternative
486 interface 0 (primary) and UAS is on alternative interface 1.
487 Both protocols can work on USB2.0 and USB3.0.
488 UAS utilizes the USB 3.0 feature called streams support.
490 source "drivers/usb/gadget/legacy/Kconfig"