# # GPIO infrastructure and expanders # config HAVE_GPIO_LIB bool help Platforms select gpiolib if they use this infrastructure for all their GPIOs, usually starting with ones integrated into SOC processors. menu "GPIO Support" depends on HAVE_GPIO_LIB 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. # put expanders in the right section, in alphabetical order comment "I2C GPIO expanders:" 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. 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. endmenu