2 # GPIO infrastructure and expanders
5 config ARCH_WANT_OPTIONAL_GPIOLIB
8 Select this config option from the architecture Kconfig, if
9 it is possible to use gpiolib on the architecture, but let the
10 user decide whether to actually build it or not.
11 Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does
12 not depend on GPIOs being available, but rather let the user
13 decide whether he needs it or not.
15 config ARCH_REQUIRE_GPIOLIB
19 Platforms select gpiolib if they use this infrastructure
20 for all their GPIOs, usually starting with ones integrated
22 Selecting this from the architecture code will cause the gpiolib
23 code to always get built in.
29 depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB
32 This enables GPIO support through the generic GPIO library.
33 You only need to enable this, if you also want to enable
34 one or more of the GPIO expansion card drivers below.
41 bool "Debug GPIO calls"
42 depends on DEBUG_KERNEL
44 Say Y here to add some extra checks and diagnostics to GPIO calls.
45 The checks help ensure that GPIOs have been properly initialized
46 before they are used and that sleeping calls aren not made from
47 nonsleeping contexts. They can make bitbanged serial protocols
48 slower. The diagnostics help catch the type of setup errors
49 that are most common when setting up new platforms or boards.
52 bool "/sys/class/gpio/... (sysfs interface)"
53 depends on SYSFS && EXPERIMENTAL
55 Say Y here to add a sysfs interface for GPIOs.
57 This is mostly useful to work around omissions in a system's
58 kernel support. Those are common in custom and semicustom
59 hardware assembled using standard kernels with a minimum of
60 custom patches. In those cases, userspace code may import
61 a given GPIO from the kernel, if no kernel driver requested it.
63 Kernel drivers may also request that a particular GPIO be
64 exported to userspace; this can be useful when debugging.
66 # put expanders in the right section, in alphabetical order
68 comment "I2C GPIO expanders:"
71 tristate "PCA953x, PCA955x, and MAX7310 I/O ports"
74 Say yes here to provide access to several register-oriented
75 SMBus I/O expanders, made mostly by NXP or TI. Compatible
78 4 bits: pca9536, pca9537
80 8 bits: max7310, pca9534, pca9538, pca9554, pca9557
82 16 bits: pca9535, pca9539, pca9555
84 This driver can also be built as a module. If so, the module
85 will be called pca953x.
88 tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
91 Say yes here to provide access to most "quasi-bidirectional" I2C
92 GPIO expanders used for additional digital outputs or inputs.
93 Most of these parts are from NXP, though TI is a second source for
94 some of them. Compatible models include:
96 8 bits: pcf8574, pcf8574a, pca8574, pca8574a,
97 pca9670, pca9672, pca9674, pca9674a,
100 16 bits: pcf8575, pcf8575c, pca8575,
101 pca9671, pca9673, pca9675
103 Your board setup code will need to declare the expanders in
104 use, and assign numbers to the GPIOs they expose. Those GPIOs
105 can then be used from drivers and other kernel code, just like
106 other GPIOs, but only accessible from task contexts.
108 This driver provides an in-kernel interface to those GPIOs using
109 platform-neutral GPIO calls.
111 comment "PCI GPIO expanders:"
114 tristate "BT8XX GPIO abuser"
115 depends on PCI && VIDEO_BT848=n
117 The BT8xx frame grabber chip has 24 GPIO pins than can be abused
118 as a cheap PCI GPIO card.
120 This chip can be found on Miro, Hauppauge and STB TV-cards.
122 The card needs to be physically altered for using it as a
123 GPIO card. For more information on how to build a GPIO card
124 from a BT8xx TV card, see the documentation file at
125 Documentation/bt8xxgpio.txt
129 comment "SPI GPIO expanders:"
132 tristate "Maxim MAX7301 GPIO expander"
133 depends on SPI_MASTER
135 gpio driver for Maxim MAX7301 SPI GPIO expander.
138 tristate "Microchip MCP23S08 I/O expander"
139 depends on SPI_MASTER
141 SPI driver for Microchip MCP23S08 I/O expander. This provides
142 a GPIO interface supporting inputs and outputs.