# # GPIO infrastructure and expanders # config ARCH_WANT_OPTIONAL_GPIOLIB bool help Select this config option from the architecture Kconfig, if it is possible to use gpiolib on the architecture, but let the user decide whether to actually build it or not. Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does not depend on GPIOs being available, but rather let the user decide whether he needs it or not. config ARCH_REQUIRE_GPIOLIB bool select GPIOLIB help Platforms select gpiolib if they use this infrastructure for all their GPIOs, usually starting with ones integrated into SOC processors. Selecting this from the architecture code will cause the gpiolib code to always get built in. menuconfig GPIOLIB bool "GPIO Support" depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB select GENERIC_GPIO help This enables GPIO support through the generic GPIO library. You only need to enable this, if you also want to enable one or more of the GPIO expansion card drivers below. If unsure, say N. if GPIOLIB config DEBUG_GPIO bool "Debug GPIO calls" depends on DEBUG_KERNEL help Say Y here to add some extra checks and diagnostics to GPIO calls. The checks help ensure that GPIOs have been properly initialized before they are used and that sleeping calls aren not made from nonsleeping contexts. They can make bitbanged serial protocols slower. The diagnostics help catch the type of setup errors that are most common when setting up new platforms or boards. config GPIO_SYSFS bool "/sys/class/gpio/... (sysfs interface)" depends on SYSFS && EXPERIMENTAL help Say Y here to add a sysfs interface for GPIOs. This is mostly useful to work around omissions in a system's kernel support. Those are common in custom and semicustom hardware assembled using standard kernels with a minimum of custom patches. In those cases, userspace code may import a given GPIO from the kernel, if no kernel driver requested it. Kernel drivers may also request that a particular GPIO be exported to userspace; this can be useful when debugging. # put expanders in the right section, in alphabetical order comment "Memory mapped GPIO expanders:" config GPIO_XILINX bool "Xilinx GPIO support" depends on PPC_OF help Say yes here to support the Xilinx FPGA GPIO device comment "I2C GPIO expanders:" config GPIO_MAX732X tristate "MAX7319, MAX7320-7327 I2C Port Expanders" depends on I2C help Say yes here to support the MAX7319, MAX7320-7327 series of I2C Port Expanders. Each IO port on these chips has a fixed role of Input (designated by 'I'), Push-Pull Output ('O'), or Open-Drain Input and Output (designed by 'P'). The combinations are listed below: 8 bits: max7319 (8I), max7320 (8O), max7321 (8P), max7322 (4I4O), max7323 (4P4O) 16 bits: max7324 (8I8O), max7325 (8P8O), max7326 (4I12O), max7327 (4P12O) Board setup code must specify the model to use, and the start number for these GPIOs. config GPIO_PCA953X tristate "PCA953x, PCA955x, and MAX7310 I/O ports" depends on I2C help Say yes here to provide access to several register-oriented SMBus I/O expanders, made mostly by NXP or TI. Compatible models include: 4 bits: pca9536, pca9537 8 bits: max7310, pca9534, pca9538, pca9554, pca9557 16 bits: pca9535, pca9539, pca9555 This driver can also be built as a module. If so, the module will be called pca953x. config GPIO_PCF857X tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders" depends on I2C help Say yes here to provide access to most "quasi-bidirectional" I2C GPIO expanders used for additional digital outputs or inputs. Most of these parts are from NXP, though TI is a second source for some of them. Compatible models include: 8 bits: pcf8574, pcf8574a, pca8574, pca8574a, pca9670, pca9672, pca9674, pca9674a, max7328, max7329 16 bits: pcf8575, pcf8575c, pca8575, pca9671, pca9673, pca9675 Your board setup code will need to declare the expanders in use, and assign numbers to the GPIOs they expose. Those GPIOs can then be used from drivers and other kernel code, just like other GPIOs, but only accessible from task contexts. This driver provides an in-kernel interface to those GPIOs using platform-neutral GPIO calls. config GPIO_TWL4030 tristate "TWL4030, TWL5030, and TPS659x0 GPIOs" depends on TWL4030_CORE help Say yes here to access the GPIO signals of various multi-function power management chips from Texas Instruments. comment "PCI GPIO expanders:" config GPIO_BT8XX tristate "BT8XX GPIO abuser" depends on PCI && VIDEO_BT848=n help The BT8xx frame grabber chip has 24 GPIO pins than can be abused as a cheap PCI GPIO card. This chip can be found on Miro, Hauppauge and STB TV-cards. The card needs to be physically altered for using it as a GPIO card. For more information on how to build a GPIO card from a BT8xx TV card, see the documentation file at Documentation/bt8xxgpio.txt If unsure, say N. comment "SPI GPIO expanders:" config GPIO_MAX7301 tristate "Maxim MAX7301 GPIO expander" depends on SPI_MASTER help gpio driver for Maxim MAX7301 SPI GPIO expander. config GPIO_MCP23S08 tristate "Microchip MCP23S08 I/O expander" depends on SPI_MASTER help SPI driver for Microchip MCP23S08 I/O expander. This provides a GPIO interface supporting inputs and outputs. endif