2 # GPIO infrastructure and drivers
5 config ARCH_HAVE_CUSTOM_GPIO_H
8 Selecting this config option from the architecture Kconfig allows
9 the architecture to provide a custom asm/gpio.h implementation
10 overriding the default implementations. New uses of this are
13 config ARCH_WANT_OPTIONAL_GPIOLIB
16 Select this config option from the architecture Kconfig, if
17 it is possible to use gpiolib on the architecture, but let the
18 user decide whether to actually build it or not.
19 Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does
20 not depend on GPIOs being available, but rather let the user
21 decide whether he needs it or not.
23 config ARCH_REQUIRE_GPIOLIB
27 Platforms select gpiolib if they use this infrastructure
28 for all their GPIOs, usually starting with ones integrated
30 Selecting this from the architecture code will cause the gpiolib
31 code to always get built in.
36 depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB
38 This enables GPIO support through the generic GPIO library.
39 You only need to enable this, if you also want to enable
40 one or more of the GPIO drivers below.
58 config GPIOLIB_IRQCHIP
63 bool "Debug GPIO calls"
64 depends on DEBUG_KERNEL
66 Say Y here to add some extra checks and diagnostics to GPIO calls.
67 These checks help ensure that GPIOs have been properly initialized
68 before they are used, and that sleeping calls are not made from
69 non-sleeping contexts. They can make bitbanged serial protocols
70 slower. The diagnostics help catch the type of setup errors
71 that are most common when setting up new platforms or boards.
74 bool "/sys/class/gpio/... (sysfs interface)"
77 Say Y here to add a sysfs interface for GPIOs.
79 This is mostly useful to work around omissions in a system's
80 kernel support. Those are common in custom and semicustom
81 hardware assembled using standard kernels with a minimum of
82 custom patches. In those cases, userspace code may import
83 a given GPIO from the kernel, if no kernel driver requested it.
85 Kernel drivers may also request that a particular GPIO be
86 exported to userspace; this can be useful when debugging.
91 # put drivers in the right section, in alphabetical order
94 tristate "Dialog DA9052 GPIO"
95 depends on PMIC_DA9052
97 Say yes here to enable the GPIO driver for the DA9052 chip.
100 tristate "Dialog Semiconductor DA9055 GPIO"
101 depends on MFD_DA9055
103 Say yes here to enable the GPIO driver for the DA9055 chip.
105 The Dialog DA9055 PMIC chip has 3 GPIO pins that can be
106 be controller by this driver.
108 If driver is built as a module it will be called gpio-da9055.
113 comment "Memory mapped GPIO drivers:"
116 tristate "CLPS711X GPIO support"
117 depends on ARCH_CLPS711X || COMPILE_TEST
120 Say yes here to support GPIO on CLPS711X SoCs.
123 bool "TI Davinci/Keystone GPIO support"
124 default y if ARCH_DAVINCI
125 depends on ARM && (ARCH_DAVINCI || ARCH_KEYSTONE)
127 Say yes here to enable GPIO support for TI Davinci/Keystone SoCs.
129 config GPIO_GENERIC_PLATFORM
130 tristate "Generic memory-mapped GPIO controller support (MMIO platform device)"
133 Say yes here to support basic platform_device memory-mapped GPIO controllers.
136 tristate "Synopsys DesignWare APB GPIO driver"
138 select GENERIC_IRQ_CHIP
141 Say Y or M here to build support for the Synopsys DesignWare APB
145 tristate "IT8761E GPIO support"
146 depends on X86 # unconditional access to IO space.
148 Say yes here to support GPIO functionality of IT8761E super I/O chip.
151 tristate "Emma Mobile GPIO"
152 depends on ARM && OF_GPIO
154 Say yes here to support GPIO on Renesas Emma Mobile SoCs.
158 depends on ARCH_EP93XX
162 bool "LSI ZEVIO SoC memory mapped GPIOs"
163 depends on ARM && OF_GPIO
165 Say yes here to support the GPIO controller in LSI ZEVIO SoCs.
167 config GPIO_MM_LANTIQ
168 bool "Lantiq Memory mapped GPIOs"
169 depends on LANTIQ && SOC_XWAY
171 This enables support for memory mapped GPIOs on the External Bus Unit
172 (EBU) found on Lantiq SoCs. The gpios are output only as they are
173 created by attaching a 16bit latch to the bus.
176 tristate "F71882FG and F71889F GPIO support"
179 This option enables support for GPIOs found on Fintek Super-I/O
180 chips F71882FG and F71889F.
182 To compile this driver as a module, choose M here: the module will
183 be called f7188x-gpio.
186 bool "MOXART GPIO support"
187 depends on ARCH_MOXART
189 Select this option to enable GPIO driver for
190 MOXA ART SoC devices.
194 depends on PPC_MPC52xx
197 bool "MPC512x/MPC8xxx GPIO support"
198 depends on PPC_MPC512x || PPC_MPC831x || PPC_MPC834x || PPC_MPC837x || \
199 FSL_SOC_BOOKE || PPC_86xx
201 Say Y here if you're going to use hardware that connects to the
202 MPC512x/831x/834x/837x/8572/8610 GPIOs.
205 tristate "Qualcomm MSM GPIO v1"
206 depends on GPIOLIB && ARCH_MSM && (ARCH_MSM7X00A || ARCH_MSM7X30 || ARCH_QSD8X50)
208 Say yes here to support the GPIO interface on ARM v6 based
209 Qualcomm MSM chips. Most of the pins on the MSM can be
210 selected for GPIO, and are controlled by this driver.
213 tristate "Qualcomm MSM GPIO v2"
214 depends on GPIOLIB && OF && ARCH_QCOM
216 Say yes here to support the GPIO interface on ARM v7 based
217 Qualcomm MSM chips. Most of the pins on the MSM can be
218 selected for GPIO, and are controlled by this driver.
222 depends on PLAT_ORION
225 select GENERIC_IRQ_CHIP
231 select GENERIC_IRQ_CHIP
237 select GENERIC_IRQ_CHIP
240 tristate "Cavium OCTEON GPIO"
241 depends on GPIOLIB && CAVIUM_OCTEON_SOC
244 Say yes here to support the on-chip GPIO lines on the OCTEON
248 bool "TI OMAP GPIO support" if COMPILE_TEST && !ARCH_OMAP2PLUS
249 default y if ARCH_OMAP
251 select GENERIC_IRQ_CHIP
252 select GPIOLIB_IRQCHIP
254 Say yes here to enable GPIO support for TI OMAP SoCs.
257 bool "PrimeCell PL061 GPIO support"
260 select GPIOLIB_IRQCHIP
262 Say yes here to support the PrimeCell PL061 GPIO device
265 bool "PXA GPIO support"
266 depends on ARCH_PXA || ARCH_MMP
268 Say yes here to support the PXA GPIO device
271 tristate "Renesas R-Car GPIO"
272 depends on ARM && (ARCH_SHMOBILE || COMPILE_TEST)
274 Say yes here to support GPIO on Renesas R-Car SoCs.
278 depends on PLAT_SAMSUNG
280 Legacy GPIO support. Use only for platforms without support for
284 tristate "SMSC SCH311x SuperI/O GPIO"
286 Driver to enable the GPIOs found on SMSC SMSC SCH3112, SCH3114 and
287 SCH3116 "Super I/O" chipsets.
289 To compile this driver as a module, choose M here: the module will
290 be called gpio-sch311x.
292 config GPIO_SPEAR_SPICS
293 bool "ST SPEAr13xx SPI Chip Select as GPIO support"
294 depends on PLAT_SPEAR
295 select GENERIC_IRQ_CHIP
297 Say yes here to support ST SPEAr SPI Chip Select as GPIO device
300 bool "STA2x11/ConneXt GPIO support"
301 depends on MFD_STA2X11
302 select GENERIC_IRQ_CHIP
304 Say yes here to support the STA2x11/ConneXt GPIO device.
305 The GPIO module has 128 GPIO pins with alternate functions.
308 tristate "GPIO based on SYSCON"
309 depends on MFD_SYSCON && OF
311 Say yes here to support GPIO functionality though SYSCON driver.
314 tristate "TS-5500 DIO blocks and compatibles"
315 depends on TS5500 || COMPILE_TEST
317 This driver supports Digital I/O exposed by pin blocks found on some
318 Technologic Systems platforms. It includes, but is not limited to, 3
319 blocks of the TS-5500: DIO1, DIO2 and the LCD port, and the TS-5600
323 bool "Toumaz Xenif TZ1090 GPIO support"
324 depends on SOC_TZ1090
325 select GENERIC_IRQ_CHIP
328 Say yes here to support Toumaz Xenif TZ1090 GPIOs.
330 config GPIO_TZ1090_PDC
331 bool "Toumaz Xenif TZ1090 PDC GPIO support"
332 depends on SOC_TZ1090
335 Say yes here to support Toumaz Xenif TZ1090 PDC GPIOs.
338 bool "Xilinx GPIO support"
339 depends on PPC_OF || MICROBLAZE || ARCH_ZYNQ
341 Say yes here to support the Xilinx FPGA GPIO device
344 tristate "Xilinx Zynq GPIO support"
346 select GPIOLIB_IRQCHIP
348 Say yes here to support Xilinx Zynq GPIO controller.
351 bool "Xtensa GPIO32 support"
353 depends on HAVE_XTENSA_GPIO32
356 Say yes here to support the Xtensa internal GPIO32 IMPWIRE (input)
357 and EXPSTATE (output) ports
360 tristate "NEC VR4100 series General-purpose I/O Uint support"
361 depends on CPU_VR41XX
363 Say yes here to support the NEC VR4100 series General-purpose I/O Uint
366 tristate "Intel SCH/TunnelCreek/Centerton GPIO"
367 depends on PCI && X86
371 Say yes here to support GPIO interface on Intel Poulsbo SCH,
372 Intel Tunnel Creek processor or Intel Centerton processor.
373 The Intel SCH contains a total of 14 GPIO pins. Ten GPIOs are
374 powered by the core power rail and are turned off during sleep
375 modes (S3 and higher). The remaining four GPIOs are powered by
376 the Intel SCH suspend power supply. These GPIOs remain
377 active during S3. The suspend powered GPIOs can be used to wake the
378 system from the Suspend-to-RAM state.
379 The Intel Tunnel Creek processor has 5 GPIOs powered by the
380 core power rail and 9 from suspend power supply.
381 The Intel Centerton processor has a total of 30 GPIO pins.
382 Twenty-one are powered by the core power rail and 9 from the
383 suspend power supply.
386 tristate "Intel ICH GPIO"
387 depends on PCI && X86
391 Say yes here to support the GPIO functionality of a number of Intel
392 ICH-based chipsets. Currently supported devices: ICH6, ICH7, ICH8
393 ICH9, ICH10, Series 5/3400 (eg Ibex Peak), Series 6/C200 (eg
394 Cougar Point), NM10 (Tiger Point), and 3100 (Whitmore Lake).
399 tristate "Intel IOP GPIO"
400 depends on ARM && (ARCH_IOP32X || ARCH_IOP33X)
402 Say yes here to support the GPIO functionality of a number of Intel
408 tristate "VIA VX855/VX875 GPIO"
413 Support access to the VX855/VX875 GPIO lines through the gpio library.
415 This driver provides common support for accessing the device,
416 additional drivers must be enabled in order to use the
417 functionality of the device.
420 bool "GE FPGA based GPIO"
423 Support for common GPIO functionality provided on some GE Single Board
426 This driver provides basic support (configure as input or output, read
427 and write pin state) for GPIO implemented in a number of GE single
430 config GPIO_LYNXPOINT
431 tristate "Intel Lynxpoint GPIO support"
432 depends on ACPI && X86
433 select GPIOLIB_IRQCHIP
435 driver for GPIO functionality on Intel Lynxpoint PCH chipset
436 Requires ACPI device enumeration code to set up a platform device.
439 tristate "Aeroflex Gaisler GRGPIO support"
444 Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
445 VHDL IP core library.
449 select GENERIC_IRQ_CHIP
452 comment "I2C GPIO expanders:"
455 tristate "Wolfson Microelectronics Arizona class devices"
456 depends on MFD_ARIZONA
458 Support for GPIOs on Wolfson Arizona class devices.
460 config GPIO_CRYSTAL_COVE
461 tristate "GPIO support for Crystal Cove PMIC"
462 depends on INTEL_SOC_PMIC
463 select GPIOLIB_IRQCHIP
465 Support for GPIO pins on Crystal Cove PMIC.
467 Say Yes if you have a Intel SoC based tablet with Crystal Cove PMIC
470 This driver can also be built as a module. If so, the module will be
471 called gpio-crystalcove.
474 tristate "TI/National Semiconductor LP3943 GPIO expander"
475 depends on MFD_LP3943
477 GPIO driver for LP3943 MFD.
478 LP3943 can be used as a GPIO expander which provides up to 16 GPIOs.
479 Open drain outputs are required for this usage.
482 tristate "Maxim MAX7300 GPIO expander"
486 GPIO driver for Maxim MAX7300 I2C-based GPIO expander.
489 tristate "MAX7319, MAX7320-7327 I2C Port Expanders"
492 Say yes here to support the MAX7319, MAX7320-7327 series of I2C
493 Port Expanders. Each IO port on these chips has a fixed role of
494 Input (designated by 'I'), Push-Pull Output ('O'), or Open-Drain
495 Input and Output (designed by 'P'). The combinations are listed
498 8 bits: max7319 (8I), max7320 (8O), max7321 (8P),
499 max7322 (4I4O), max7323 (4P4O)
501 16 bits: max7324 (8I8O), max7325 (8P8O),
502 max7326 (4I12O), max7327 (4P12O)
504 Board setup code must specify the model to use, and the start
505 number for these GPIOs.
507 config GPIO_MAX732X_IRQ
508 bool "Interrupt controller support for MAX732x"
509 depends on GPIO_MAX732X=y
511 Say yes here to enable the max732x to be used as an interrupt
512 controller. It requires the driver to be built in the kernel.
514 config GPIO_MC9S08DZ60
515 bool "MX35 3DS BOARD MC9S08DZ60 GPIO functions"
516 depends on I2C=y && MACH_MX35_3DS
518 Select this to enable the MC9S08DZ60 GPIO driver
521 tristate "PCA95[357]x, PCA9698, TCA64xx, and MAX7310 I/O ports"
524 Say yes here to provide access to several register-oriented
525 SMBus I/O expanders, made mostly by NXP or TI. Compatible
528 4 bits: pca9536, pca9537
530 8 bits: max7310, max7315, pca6107, pca9534, pca9538, pca9554,
531 pca9556, pca9557, pca9574, tca6408, xra1202
533 16 bits: max7312, max7313, pca9535, pca9539, pca9555, pca9575,
538 40 bits: pca9505, pca9698
540 config GPIO_PCA953X_IRQ
541 bool "Interrupt controller support for PCA953x"
542 depends on GPIO_PCA953X=y
543 select GPIOLIB_IRQCHIP
545 Say yes here to enable the pca953x to be used as an interrupt
546 controller. It requires the driver to be built in the kernel.
549 tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
553 Say yes here to provide access to most "quasi-bidirectional" I2C
554 GPIO expanders used for additional digital outputs or inputs.
555 Most of these parts are from NXP, though TI is a second source for
556 some of them. Compatible models include:
558 8 bits: pcf8574, pcf8574a, pca8574, pca8574a,
559 pca9670, pca9672, pca9674, pca9674a,
562 16 bits: pcf8575, pcf8575c, pca8575,
563 pca9671, pca9673, pca9675
565 Your board setup code will need to declare the expanders in
566 use, and assign numbers to the GPIOs they expose. Those GPIOs
567 can then be used from drivers and other kernel code, just like
568 other GPIOs, but only accessible from task contexts.
570 This driver provides an in-kernel interface to those GPIOs using
571 platform-neutral GPIO calls.
574 bool "RICOH RC5T583 GPIO"
575 depends on MFD_RC5T583
577 Select this option to enable GPIO driver for the Ricoh RC5T583
579 This driver provides the support for driving/reading the gpio pins
580 of RC5T583 device through standard gpio library.
583 bool "Semtech SX150x I2C GPIO expander"
587 Say yes here to provide support for Semtech SX150-series I2C
588 GPIO expanders. Compatible models include:
596 select GPIOLIB_IRQCHIP
598 This enables support for the GPIOs found on the STMPE I/O
602 bool "XWAY STP GPIOs"
605 This enables support for the Serial To Parallel (STP) unit found on
606 XWAY SoC. The STP allows the SoC to drive a shift registers cascade,
607 that can be up to 24 bit. This peripheral is aimed at driving leds.
608 Some of the gpios/leds can be auto updated by the soc with dsl and
613 depends on MFD_TC3589X
614 select GPIOLIB_IRQCHIP
616 This enables support for the GPIOs found on the TC3589X
620 tristate "TI TPS65912 GPIO"
621 depends on (MFD_TPS65912_I2C || MFD_TPS65912_SPI)
623 This driver supports TPS65912 gpio chip
626 tristate "TWL4030, TWL5030, and TPS659x0 GPIOs"
627 depends on TWL4030_CORE
629 Say yes here to access the GPIO signals of various multi-function
630 power management chips from Texas Instruments.
633 tristate "TWL6040 GPO"
634 depends on TWL6040_CORE
636 Say yes here to access the GPO signals of twl6040
637 audio chip from Texas Instruments.
640 tristate "WM831x GPIOs"
641 depends on MFD_WM831X
643 Say yes here to access the GPIO signals of WM831x power management
644 chips from Wolfson Microelectronics.
647 tristate "WM8350 GPIOs"
648 depends on MFD_WM8350
650 Say yes here to access the GPIO signals of WM8350 power management
651 chips from Wolfson Microelectronics.
654 tristate "WM8994 GPIOs"
655 depends on MFD_WM8994
657 Say yes here to access the GPIO signals of WM8994 audio hub
658 CODECs from Wolfson Microelectronics.
661 tristate "GPIO Support for ADP5520 PMIC"
662 depends on PMIC_ADP5520
664 This option enables support for on-chip GPIO found
665 on Analog Devices ADP5520 PMICs.
668 tristate "ADP5588 I2C GPIO expander"
671 This option enables support for 18 GPIOs found
672 on Analog Devices ADP5588 GPIO Expanders.
674 config GPIO_ADP5588_IRQ
675 bool "Interrupt controller support for ADP5588"
676 depends on GPIO_ADP5588=y
678 Say yes here to enable the adp5588 to be used as an interrupt
679 controller. It requires the driver to be built in the kernel.
682 tristate "Avionic Design N-bit GPIO expander"
683 depends on I2C && OF_GPIO
685 This option enables support for N GPIOs found on Avionic Design
686 I2C GPIO expanders. The register space will be extended by powers
687 of two, so the controller will need to accommodate for that. For
688 example: if a controller provides 48 pins, 6 registers will be
689 enough to represent all pins, but the driver will assume a
690 register layout for 64 pins (8 registers).
692 comment "PCI GPIO expanders:"
695 tristate "AMD CS5535/CS5536 GPIO support"
696 depends on MFD_CS5535
698 The AMD CS5535 and CS5536 southbridges support 28 GPIO pins that
699 can be used for quite a number of things. The CS5535/6 is found on
700 AMD Geode and Lemote Yeeloong devices.
705 tristate "BT8XX GPIO abuser"
706 depends on PCI && VIDEO_BT848=n
708 The BT8xx frame grabber chip has 24 GPIO pins that can be abused
709 as a cheap PCI GPIO card.
711 This chip can be found on Miro, Hauppauge and STB TV-cards.
713 The card needs to be physically altered for using it as a
714 GPIO card. For more information on how to build a GPIO card
715 from a BT8xx TV card, see the documentation file at
716 Documentation/bt8xxgpio.txt
721 tristate "AMD 8111 GPIO driver"
724 The AMD 8111 south bridge contains 32 GPIO pins which can be used.
726 Note, that usually system firmware/ACPI handles GPIO pins on their
727 own and users might easily break their systems with uncarefull usage
732 config GPIO_INTEL_MID
733 bool "Intel Mid GPIO support"
734 depends on PCI && X86
735 select GPIOLIB_IRQCHIP
737 Say Y here to support Intel Mid GPIO.
740 tristate "Intel EG20T PCH/LAPIS Semiconductor IOH(ML7223/ML7831) GPIO"
741 depends on PCI && (X86_32 || COMPILE_TEST)
742 select GENERIC_IRQ_CHIP
744 This driver is for PCH(Platform controller Hub) GPIO of Intel Topcliff
745 which is an IOH(Input/Output Hub) for x86 embedded processor.
746 This driver can access PCH GPIO device.
748 This driver also can be used for LAPIS Semiconductor IOH(Input/
749 Output Hub), ML7223 and ML7831.
750 ML7223 IOH is for MP(Media Phone) use.
751 ML7831 IOH is for general purpose use.
752 ML7223/ML7831 is companion chip for Intel Atom E6xx series.
753 ML7223/ML7831 is completely compatible for Intel EG20T PCH.
756 tristate "OKI SEMICONDUCTOR ML7213 IOH GPIO support"
758 select GENERIC_IRQ_CHIP
760 ML7213 is companion chip for Intel Atom E6xx series.
761 This driver can be used for OKI SEMICONDUCTOR ML7213 IOH(Input/Output
762 Hub) which is for IVI(In-Vehicle Infotainment) use.
763 This driver can access the IOH's GPIO device.
765 config GPIO_SODAVILLE
766 bool "Intel Sodaville GPIO support"
767 depends on X86 && PCI && OF
769 select GENERIC_IRQ_CHIP
771 Say Y here to support Intel Sodaville GPIO.
773 config GPIO_TIMBERDALE
774 bool "Support for timberdale GPIO IP"
775 depends on MFD_TIMBERDALE
777 Add support for the GPIO IP in the timberdale FPGA.
780 tristate "RDC R-321x GPIO support"
785 Support for the RDC R321x SoC GPIOs over southbridge
786 PCI configuration space.
788 comment "SPI GPIO expanders:"
791 tristate "Maxim MAX7301 GPIO expander"
792 depends on SPI_MASTER
795 GPIO driver for Maxim MAX7301 SPI-based GPIO expander.
798 tristate "Microchip MCP23xxx I/O expander"
800 depends on (SPI_MASTER && !I2C) || I2C
802 SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017
804 This provides a GPIO interface supporting inputs and outputs.
805 The I2C versions of the chips can be used as interrupt-controller.
808 tristate "Freescale MC33880 high-side/low-side switch"
809 depends on SPI_MASTER
811 SPI driver for Freescale MC33880 high-side/low-side switch.
812 This provides GPIO interface supporting inputs and outputs.
815 tristate "74x164 serial-in/parallel-out 8-bits shift register"
816 depends on SPI_MASTER && OF
818 Driver for 74x164 compatible serial-in/parallel-out 8-outputs
819 shift registers. This driver can be used to provide access
820 to more gpio outputs.
822 comment "AC97 GPIO expanders:"
825 tristate "Philips UCB1400 GPIO"
826 depends on UCB1400_CORE
828 This enables support for the Philips UCB1400 GPIO pins.
829 The UCB1400 is an AC97 audio codec.
831 comment "LPC GPIO expanders:"
834 tristate "Kontron ETX / COMexpress GPIO"
835 depends on MFD_KEMPLD
837 This enables support for the PLD GPIO interface on some Kontron ETX
838 and COMexpress (ETXexpress) modules.
840 This driver can also be built as a module. If so, the module will be
843 comment "MODULbus GPIO expanders:"
846 tristate "Janz VMOD-TTL Digital IO Module"
847 depends on MFD_JANZ_CMODIO
849 This enables support for the Janz VMOD-TTL Digital IO module.
850 This driver provides support for driving the pins in output
851 mode only. Input mode is not supported.
854 bool "TI PALMAS series PMICs GPIO"
855 depends on MFD_PALMAS
857 Select this option to enable GPIO driver for the TI PALMAS
862 depends on MFD_TPS6586X
864 Select this option to enable GPIO driver for the TPS6586X
869 depends on MFD_TPS65910
871 Select this option to enable GPIO driver for the TPS65910
875 bool "Intel MSIC mixed signal gpio support"
876 depends on MFD_INTEL_MSIC
878 Enable support for GPIO on intel MSIC controllers found in
882 bool "Broadcom Kona GPIO"
885 Turn on GPIO support for Broadcom "Kona" chips.
887 comment "USB GPIO expanders:"
889 config GPIO_VIPERBOARD
890 tristate "Viperboard GPIO a & b support"
891 depends on MFD_VIPERBOARD && USB
893 Say yes here to access the GPIO signals of Nano River
894 Technologies Viperboard. There are two GPIO chips on the
895 board: gpioa and gpiob.
896 See viperboard API specification and Nano
897 River Tech's viperboard.h for detailed meaning
898 of the module parameters.