2 # USB Gadget support on a system involves
3 # (a) a peripheral controller, and
4 # (b) the gadget driver using it.
6 # NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
8 # - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
9 # - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
10 # - Some systems have both kinds of controllers.
12 # With help from a special transceiver and a "Mini-AB" jack, systems with
13 # both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
17 tristate "USB Gadget Support"
19 USB is a master/slave protocol, organized with one master
20 host (such as a PC) controlling up to 127 peripheral devices.
21 The USB hardware is asymmetric, which makes it easier to set up:
22 you can't connect a "to-the-host" connector to a peripheral.
24 Linux can run in the host, or in the peripheral. In both cases
25 you need a low level bus controller driver, and some software
26 talking to it. Peripheral controllers are often discrete silicon,
27 or are integrated with the CPU in a microcontroller. The more
28 familiar host side controllers have names like "EHCI", "OHCI",
29 or "UHCI", and are usually integrated into southbridges on PC
32 Enable this configuration option if you want to run Linux inside
33 a USB peripheral device. Configure one hardware driver for your
34 peripheral/device side bus controller, and a "gadget driver" for
35 your peripheral protocol. (If you use modular gadget drivers,
36 you may configure more than one.)
38 If in doubt, say "N" and don't enable these drivers; most people
39 don't have this kind of hardware (except maybe inside Linux PDAs).
41 For more information, see <http://www.linux-usb.org/gadget> and
42 the kernel DocBook documentation for this API.
46 config USB_GADGET_DEBUG
47 boolean "Debugging messages (DEVELOPMENT)"
48 depends on DEBUG_KERNEL
50 Many controller and gadget drivers will print some debugging
51 messages if you use this option to ask for those messages.
53 Avoid enabling these messages, even if you're actively
54 debugging such a driver. Many drivers will emit so many
55 messages that the driver timings are affected, which will
56 either create new failure modes or remove the one you're
57 trying to track down. Never enable these messages for a
60 config USB_GADGET_DEBUG_FILES
61 boolean "Debugging information files (DEVELOPMENT)"
64 Some of the drivers in the "gadget" framework can expose
65 debugging information in files such as /proc/driver/udc
66 (for a peripheral controller). The information in these
67 files may help when you're troubleshooting or bringing up a
68 driver on a new board. Enable these files by choosing "Y"
69 here. If in doubt, or to conserve kernel memory, say "N".
71 config USB_GADGET_DEBUG_FS
72 boolean "Debugging information files in debugfs (DEVELOPMENT)"
75 Some of the drivers in the "gadget" framework can expose
76 debugging information in files under /sys/kernel/debug/.
77 The information in these files may help when you're
78 troubleshooting or bringing up a driver on a new board.
79 Enable these files by choosing "Y" here. If in doubt, or
80 to conserve kernel memory, say "N".
82 config USB_GADGET_VBUS_DRAW
83 int "Maximum VBUS Power usage (2-500 mA)"
87 Some devices need to draw power from USB when they are
88 configured, perhaps to operate circuitry or to recharge
89 batteries. This is in addition to any local power supply,
90 such as an AC adapter or batteries.
92 Enter the maximum power your device draws through USB, in
93 milliAmperes. The permitted range of values is 2 - 500 mA;
94 0 mA would be legal, but can make some hosts misbehave.
96 This value will be used except for system-specific gadget
97 drivers that have more specific information.
99 config USB_GADGET_SELECTED
103 # USB Peripheral Controller Support
105 # The order here is alphabetical, except that integrated controllers go
106 # before discrete ones so they will be the initial/default value:
107 # - integrated/SOC controllers first
108 # - licensed IP used in both SOC and discrete versions
109 # - discrete ones (including all PCI-only controllers)
110 # - debug/dummy gadget+hcd is last.
113 prompt "USB Peripheral Controller"
114 depends on USB_GADGET
116 A USB device uses a controller to talk to its host.
117 Systems should have only one such upstream link.
118 Many controller drivers are platform-specific; these
119 often need board-specific hooks.
122 # Integrated controllers
125 config USB_GADGET_AT91
126 boolean "Atmel AT91 USB Device Port"
127 depends on ARCH_AT91 && !ARCH_AT91SAM9RL && !ARCH_AT91CAP9 && !ARCH_AT91SAM9G45
128 select USB_GADGET_SELECTED
130 Many Atmel AT91 processors (such as the AT91RM2000) have a
131 full speed USB Device Port with support for five configurable
132 endpoints (plus endpoint zero).
134 Say "y" to link the driver statically, or "m" to build a
135 dynamically linked module called "at91_udc" and force all
136 gadget drivers to also be dynamically linked.
140 depends on USB_GADGET_AT91
143 config USB_GADGET_ATMEL_USBA
145 select USB_GADGET_DUALSPEED
146 depends on AVR32 || ARCH_AT91CAP9 || ARCH_AT91SAM9RL || ARCH_AT91SAM9G45
148 USBA is the integrated high-speed USB Device controller on
149 the AT32AP700x, some AT91SAM9 and AT91CAP9 processors from Atmel.
151 config USB_ATMEL_USBA
153 depends on USB_GADGET_ATMEL_USBA
155 select USB_GADGET_SELECTED
157 config USB_GADGET_FSL_USB2
158 boolean "Freescale Highspeed USB DR Peripheral Controller"
159 depends on FSL_SOC || ARCH_MXC
160 select USB_GADGET_DUALSPEED
162 Some of Freescale PowerPC processors have a High Speed
163 Dual-Role(DR) USB controller, which supports device mode.
165 The number of programmable endpoints is different through
168 Say "y" to link the driver statically, or "m" to build a
169 dynamically linked module called "fsl_usb2_udc" and force
170 all gadget drivers to also be dynamically linked.
174 depends on USB_GADGET_FSL_USB2
176 select USB_GADGET_SELECTED
178 config USB_GADGET_LH7A40X
180 depends on ARCH_LH7A40X
182 This driver provides USB Device Controller driver for LH7A40x
186 depends on USB_GADGET_LH7A40X
188 select USB_GADGET_SELECTED
190 config USB_GADGET_OMAP
191 boolean "OMAP USB Device Controller"
193 select ISP1301_OMAP if MACH_OMAP_H2 || MACH_OMAP_H3 || MACH_OMAP_H4_OTG
194 select USB_OTG_UTILS if ARCH_OMAP
196 Many Texas Instruments OMAP processors have flexible full
197 speed USB device controllers, with support for up to 30
198 endpoints (plus endpoint zero). This driver supports the
199 controller in the OMAP 1611, and should work with controllers
200 in other OMAP processors too, given minor tweaks.
202 Say "y" to link the driver statically, or "m" to build a
203 dynamically linked module called "omap_udc" and force all
204 gadget drivers to also be dynamically linked.
208 depends on USB_GADGET_OMAP
210 select USB_GADGET_SELECTED
213 boolean "OTG Support"
214 depends on USB_GADGET_OMAP && ARCH_OMAP_OTG && USB_OHCI_HCD
216 The most notable feature of USB OTG is support for a
217 "Dual-Role" device, which can act as either a device
218 or a host. The initial role choice can be changed
219 later, when two dual-role devices talk to each other.
221 Select this only if your OMAP board has a Mini-AB connector.
223 config USB_GADGET_PXA25X
224 boolean "PXA 25x or IXP 4xx"
225 depends on (ARCH_PXA && PXA25x) || ARCH_IXP4XX
227 Intel's PXA 25x series XScale ARM-5TE processors include
228 an integrated full speed USB 1.1 device controller. The
229 controller in the IXP 4xx series is register-compatible.
231 It has fifteen fixed-function endpoints, as well as endpoint
232 zero (for control transfers).
234 Say "y" to link the driver statically, or "m" to build a
235 dynamically linked module called "pxa25x_udc" and force all
236 gadget drivers to also be dynamically linked.
240 depends on USB_GADGET_PXA25X
242 select USB_GADGET_SELECTED
244 # if there's only one gadget driver, using only two bulk endpoints,
245 # don't waste memory for the other endpoints
246 config USB_PXA25X_SMALL
247 depends on USB_GADGET_PXA25X
249 default n if USB_ETH_RNDIS
250 default y if USB_ZERO
252 default y if USB_G_SERIAL
254 config USB_GADGET_R8A66597
255 boolean "Renesas R8A66597 USB Peripheral Controller"
256 select USB_GADGET_DUALSPEED
258 R8A66597 is a discrete USB host and peripheral controller chip that
259 supports both full and high speed USB 2.0 data transfers.
260 It has nine configurable endpoints, and endpoint zero.
262 Say "y" to link the driver statically, or "m" to build a
263 dynamically linked module called "r8a66597_udc" and force all
264 gadget drivers to also be dynamically linked.
268 depends on USB_GADGET_R8A66597
270 select USB_GADGET_SELECTED
272 config USB_GADGET_PXA27X
274 depends on ARCH_PXA && (PXA27x || PXA3xx)
277 Intel's PXA 27x series XScale ARM v5TE processors include
278 an integrated full speed USB 1.1 device controller.
280 It has up to 23 endpoints, as well as endpoint zero (for
283 Say "y" to link the driver statically, or "m" to build a
284 dynamically linked module called "pxa27x_udc" and force all
285 gadget drivers to also be dynamically linked.
289 depends on USB_GADGET_PXA27X
291 select USB_GADGET_SELECTED
293 config USB_GADGET_S3C_HSOTG
294 boolean "S3C HS/OtG USB Device controller"
295 depends on S3C_DEV_USB_HSOTG
296 select USB_GADGET_S3C_HSOTG_PIO
298 The Samsung S3C64XX USB2.0 high-speed gadget controller
299 integrated into the S3C64XX series SoC.
303 depends on USB_GADGET_S3C_HSOTG
305 select USB_GADGET_SELECTED
307 config USB_GADGET_IMX
308 boolean "Freescale IMX USB Peripheral Controller"
311 Freescale's IMX series include an integrated full speed
312 USB 1.1 device controller. The controller in the IMX series
313 is register-compatible.
315 It has Six fixed-function endpoints, as well as endpoint
316 zero (for control transfers).
318 Say "y" to link the driver statically, or "m" to build a
319 dynamically linked module called "imx_udc" and force all
320 gadget drivers to also be dynamically linked.
324 depends on USB_GADGET_IMX
326 select USB_GADGET_SELECTED
328 config USB_GADGET_S3C2410
329 boolean "S3C2410 USB Device Controller"
330 depends on ARCH_S3C2410
332 Samsung's S3C2410 is an ARM-4 processor with an integrated
333 full speed USB 1.1 device controller. It has 4 configurable
334 endpoints, as well as endpoint zero (for control transfers).
336 This driver has been tested on the S3C2410, S3C2412, and
341 depends on USB_GADGET_S3C2410
343 select USB_GADGET_SELECTED
345 config USB_S3C2410_DEBUG
346 boolean "S3C2410 udc debug messages"
347 depends on USB_GADGET_S3C2410
350 # Controllers available in both integrated and discrete versions
353 # musb builds in ../musb along with host support
354 config USB_GADGET_MUSB_HDRC
355 boolean "Inventra HDRC USB Peripheral (TI, ADI, ...)"
356 depends on USB_MUSB_HDRC && (USB_MUSB_PERIPHERAL || USB_MUSB_OTG)
357 select USB_GADGET_DUALSPEED
358 select USB_GADGET_SELECTED
360 This OTG-capable silicon IP is used in dual designs including
361 the TI DaVinci, OMAP 243x, OMAP 343x, TUSB 6010, and ADI Blackfin
363 config USB_GADGET_M66592
364 boolean "Renesas M66592 USB Peripheral Controller"
365 select USB_GADGET_DUALSPEED
367 M66592 is a discrete USB peripheral controller chip that
368 supports both full and high speed USB 2.0 data transfers.
369 It has seven configurable endpoints, and endpoint zero.
371 Say "y" to link the driver statically, or "m" to build a
372 dynamically linked module called "m66592_udc" and force all
373 gadget drivers to also be dynamically linked.
377 depends on USB_GADGET_M66592
379 select USB_GADGET_SELECTED
382 # Controllers available only in discrete form (and all PCI controllers)
385 config USB_GADGET_AMD5536UDC
386 boolean "AMD5536 UDC"
388 select USB_GADGET_DUALSPEED
390 The AMD5536 UDC is part of the AMD Geode CS5536, an x86 southbridge.
391 It is a USB Highspeed DMA capable USB device controller. Beside ep0
392 it provides 4 IN and 4 OUT endpoints (bulk or interrupt type).
393 The UDC port supports OTG operation, and may be used as a host port
394 if it's not being used to implement peripheral or OTG roles.
396 Say "y" to link the driver statically, or "m" to build a
397 dynamically linked module called "amd5536udc" and force all
398 gadget drivers to also be dynamically linked.
400 config USB_AMD5536UDC
402 depends on USB_GADGET_AMD5536UDC
404 select USB_GADGET_SELECTED
406 config USB_GADGET_FSL_QE
407 boolean "Freescale QE/CPM USB Device Controller"
408 depends on FSL_SOC && (QUICC_ENGINE || CPM)
410 Some of Freescale PowerPC processors have a Full Speed
411 QE/CPM2 USB controller, which support device mode with 4
412 programmable endpoints. This driver supports the
413 controller in the MPC8360 and MPC8272, and should work with
414 controllers having QE or CPM2, given minor tweaks.
416 Set CONFIG_USB_GADGET to "m" to build this driver as a
417 dynamically linked module called "fsl_qe_udc".
421 depends on USB_GADGET_FSL_QE
423 select USB_GADGET_SELECTED
425 config USB_GADGET_CI13XXX
426 boolean "MIPS USB CI13xxx"
428 select USB_GADGET_DUALSPEED
430 MIPS USB IP core family device controller
431 Currently it only supports IP part number CI13412
433 Say "y" to link the driver statically, or "m" to build a
434 dynamically linked module called "ci13xxx_udc" and force all
435 gadget drivers to also be dynamically linked.
439 depends on USB_GADGET_CI13XXX
441 select USB_GADGET_SELECTED
443 config USB_GADGET_NET2280
444 boolean "NetChip 228x"
446 select USB_GADGET_DUALSPEED
448 NetChip 2280 / 2282 is a PCI based USB peripheral controller which
449 supports both full and high speed USB 2.0 data transfers.
451 It has six configurable endpoints, as well as endpoint zero
452 (for control transfers) and several endpoints with dedicated
455 Say "y" to link the driver statically, or "m" to build a
456 dynamically linked module called "net2280" and force all
457 gadget drivers to also be dynamically linked.
461 depends on USB_GADGET_NET2280
463 select USB_GADGET_SELECTED
465 config USB_GADGET_GOKU
466 boolean "Toshiba TC86C001 'Goku-S'"
469 The Toshiba TC86C001 is a PCI device which includes controllers
470 for full speed USB devices, IDE, I2C, SIO, plus a USB host (OHCI).
472 The device controller has three configurable (bulk or interrupt)
473 endpoints, plus endpoint zero (for control transfers).
475 Say "y" to link the driver statically, or "m" to build a
476 dynamically linked module called "goku_udc" and to force all
477 gadget drivers to also be dynamically linked.
481 depends on USB_GADGET_GOKU
483 select USB_GADGET_SELECTED
485 config USB_GADGET_LANGWELL
486 boolean "Intel Langwell USB Device Controller"
488 select USB_GADGET_DUALSPEED
490 Intel Langwell USB Device Controller is a High-Speed USB
491 On-The-Go device controller.
493 The number of programmable endpoints is different through
496 Say "y" to link the driver statically, or "m" to build a
497 dynamically linked module called "langwell_udc" and force all
498 gadget drivers to also be dynamically linked.
502 depends on USB_GADGET_LANGWELL
504 select USB_GADGET_SELECTED
508 # LAST -- dummy/emulated controller
511 config USB_GADGET_DUMMY_HCD
512 boolean "Dummy HCD (DEVELOPMENT)"
513 depends on USB=y || (USB=m && USB_GADGET=m)
514 select USB_GADGET_DUALSPEED
516 This host controller driver emulates USB, looping all data transfer
517 requests back to a USB "gadget driver" in the same host. The host
518 side is the master; the gadget side is the slave. Gadget drivers
519 can be high, full, or low speed; and they have access to endpoints
520 like those from NET2280, PXA2xx, or SA1100 hardware.
522 This may help in some stages of creating a driver to embed in a
523 Linux device, since it lets you debug several parts of the gadget
524 driver without its hardware or drivers being involved.
526 Since such a gadget side driver needs to interoperate with a host
527 side Linux-USB device driver, this may help to debug both sides
528 of a USB protocol stack.
530 Say "y" to link the driver statically, or "m" to build a
531 dynamically linked module called "dummy_hcd" and force all
532 gadget drivers to also be dynamically linked.
536 depends on USB_GADGET_DUMMY_HCD
538 select USB_GADGET_SELECTED
540 # NOTE: Please keep dummy_hcd LAST so that "real hardware" appears
541 # first and will be selected by default.
545 config USB_GADGET_DUALSPEED
547 depends on USB_GADGET
550 Means that gadget drivers should include extra descriptors
551 and code to handle dual-speed controllers.
557 tristate "USB Gadget Drivers"
558 depends on USB_GADGET && USB_GADGET_SELECTED
561 A Linux "Gadget Driver" talks to the USB Peripheral Controller
562 driver through the abstract "gadget" API. Some other operating
563 systems call these "client" drivers, of which "class drivers"
564 are a subset (implementing a USB device class specification).
565 A gadget driver implements one or more USB functions using
566 the peripheral hardware.
568 Gadget drivers are hardware-neutral, or "platform independent",
569 except that they sometimes must understand quirks or limitations
570 of the particular controllers they work with. For example, when
571 a controller doesn't support alternate configurations or provide
572 enough of the right types of endpoints, the gadget driver might
573 not be able work with that controller, or might need to implement
574 a less common variant of a device class protocol.
576 # this first set of drivers all depend on bulk-capable hardware.
579 tristate "Gadget Zero (DEVELOPMENT)"
581 Gadget Zero is a two-configuration device. It either sinks and
582 sources bulk data; or it loops back a configurable number of
583 transfers. It also implements control requests, for "chapter 9"
584 conformance. The driver needs only two bulk-capable endpoints, so
585 it can work on top of most device-side usb controllers. It's
586 useful for testing, and is also a working example showing how
587 USB "gadget drivers" can be written.
589 Make this be the first driver you try using on top of any new
590 USB peripheral controller driver. Then you can use host-side
591 test software, like the "usbtest" driver, to put your hardware
592 and its driver through a basic set of functional tests.
594 Gadget Zero also works with the host-side "usb-skeleton" driver,
595 and with many kinds of host-side test software. You may need
596 to tweak product and vendor IDs before host software knows about
597 this device, and arrange to select an appropriate configuration.
599 Say "y" to link the driver statically, or "m" to build a
600 dynamically linked module called "g_zero".
602 config USB_ZERO_HNPTEST
603 boolean "HNP Test Device"
604 depends on USB_ZERO && USB_OTG
606 You can configure this device to enumerate using the device
607 identifiers of the USB-OTG test device. That means that when
608 this gadget connects to another OTG device, with this one using
609 the "B-Peripheral" role, that device will use HNP to let this
610 one serve as the USB host instead (in the "B-Host" role).
613 tristate "Audio Gadget (EXPERIMENTAL)"
617 Gadget Audio is compatible with USB Audio Class specification 1.0.
618 It will include at least one AudioControl interface, zero or more
619 AudioStream interface and zero or more MIDIStream interface.
621 Gadget Audio will use on-board ALSA (CONFIG_SND) audio card to
622 playback or capture audio stream.
624 Say "y" to link the driver statically, or "m" to build a
625 dynamically linked module called "g_audio".
628 tristate "Ethernet Gadget (with CDC Ethernet support)"
631 This driver implements Ethernet style communication, in either
634 - The "Communication Device Class" (CDC) Ethernet Control Model.
635 That protocol is often avoided with pure Ethernet adapters, in
636 favor of simpler vendor-specific hardware, but is widely
637 supported by firmware for smart network devices.
639 - On hardware can't implement that protocol, a simple CDC subset
640 is used, placing fewer demands on USB.
642 RNDIS support is a third option, more demanding than that subset.
644 Within the USB device, this gadget driver exposes a network device
645 "usbX", where X depends on what other networking devices you have.
646 Treat it like a two-node Ethernet link: host, and gadget.
648 The Linux-USB host-side "usbnet" driver interoperates with this
649 driver, so that deep I/O queues can be supported. On 2.4 kernels,
650 use "CDCEther" instead, if you're using the CDC option. That CDC
651 mode should also interoperate with standard CDC Ethernet class
652 drivers on other host operating systems.
654 Say "y" to link the driver statically, or "m" to build a
655 dynamically linked module called "g_ether".
662 Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
663 and Microsoft provides redistributable binary RNDIS drivers for
664 older versions of Windows.
666 If you say "y" here, the Ethernet gadget driver will try to provide
667 a second device configuration, supporting RNDIS to talk to such
670 To make MS-Windows work with this, use Documentation/usb/linux.inf
671 as the "driver info file". For versions of MS-Windows older than
672 XP, you'll need to download drivers from Microsoft's website; a URL
673 is given in comments found in that info file.
676 tristate "Gadget Filesystem (EXPERIMENTAL)"
677 depends on EXPERIMENTAL
679 This driver provides a filesystem based API that lets user mode
680 programs implement a single-configuration USB device, including
681 endpoint I/O and control requests that don't relate to enumeration.
682 All endpoints, transfer speeds, and transfer types supported by
683 the hardware are available, through read() and write() calls.
685 Currently, this option is still labelled as EXPERIMENTAL because
686 of existing race conditions in the underlying in-kernel AIO core.
688 Say "y" to link the driver statically, or "m" to build a
689 dynamically linked module called "gadgetfs".
691 config USB_FILE_STORAGE
692 tristate "File-backed Storage Gadget"
695 The File-backed Storage Gadget acts as a USB Mass Storage
696 disk drive. As its storage repository it can use a regular
697 file or a block device (in much the same way as the "loop"
698 device driver), specified as a module parameter.
700 Say "y" to link the driver statically, or "m" to build a
701 dynamically linked module called "g_file_storage".
703 config USB_FILE_STORAGE_TEST
704 bool "File-backed Storage Gadget testing version"
705 depends on USB_FILE_STORAGE
708 Say "y" to generate the larger testing version of the
709 File-backed Storage Gadget, useful for probing the
710 behavior of USB Mass Storage hosts. Not needed for
714 tristate "Serial Gadget (with CDC ACM and CDC OBEX support)"
716 The Serial Gadget talks to the Linux-USB generic serial driver.
717 This driver supports a CDC-ACM module option, which can be used
718 to interoperate with MS-Windows hosts or with the Linux-USB
721 This driver also supports a CDC-OBEX option. You will need a
722 user space OBEX server talking to /dev/ttyGS*, since the kernel
723 itself doesn't implement the OBEX protocol.
725 Say "y" to link the driver statically, or "m" to build a
726 dynamically linked module called "g_serial".
728 For more information, see Documentation/usb/gadget_serial.txt
729 which includes instructions and a "driver info file" needed to
730 make MS-Windows work with CDC ACM.
732 config USB_MIDI_GADGET
733 tristate "MIDI Gadget (EXPERIMENTAL)"
734 depends on SND && EXPERIMENTAL
737 The MIDI Gadget acts as a USB Audio device, with one MIDI
738 input and one MIDI output. These MIDI jacks appear as
739 a sound "card" in the ALSA sound system. Other MIDI
740 connections can then be made on the gadget system, using
741 ALSA's aconnect utility etc.
743 Say "y" to link the driver statically, or "m" to build a
744 dynamically linked module called "g_midi".
747 tristate "Printer Gadget"
749 The Printer Gadget channels data between the USB host and a
750 userspace program driving the print engine. The user space
751 program reads and writes the device file /dev/g_printer to
752 receive or send printer data. It can use ioctl calls to
753 the device file to get or set printer status.
755 Say "y" to link the driver statically, or "m" to build a
756 dynamically linked module called "g_printer".
758 For more information, see Documentation/usb/gadget_printer.txt
759 which includes sample code for accessing the device file.
761 config USB_CDC_COMPOSITE
762 tristate "CDC Composite Device (Ethernet and ACM)"
765 This driver provides two functions in one configuration:
766 a CDC Ethernet (ECM) link, and a CDC ACM (serial port) link.
768 This driver requires four bulk and two interrupt endpoints,
769 plus the ability to handle altsettings. Not all peripheral
770 controllers are that capable.
772 Say "y" to link the driver statically, or "m" to build a
773 dynamically linked module.
775 # put drivers that need isochronous transfer support (for audio
776 # or video class gadget drivers), or specific hardware, here.