33 lines · plain
1What: /sys/class/gpio/2Date: July 20083KernelVersion: 2.6.274Contact: Linus Walleij <linusw@kernel.org>5Description:6 7 As a Kconfig option, individual GPIO signals may be accessed from8 userspace. GPIOs are only made available to userspace by an explicit9 "export" operation. If a given GPIO is not claimed for use by10 kernel code, it may be exported by userspace (and unexported later).11 Kernel code may export it for complete or partial access.12 13 GPIOs are identified as they are inside the kernel, using integers in14 the range 0..INT_MAX. See Documentation/admin-guide/gpio for more information.15 16 ::17 18 /sys/class/gpio19 /export ... asks the kernel to export a GPIO to userspace20 /unexport ... to return a GPIO to the kernel21 /gpioN ... for each exported GPIO #N OR22 /<LINE-NAME> ... for a properly named GPIO line23 /value ... always readable, writes fail for input GPIOs24 /direction ... r/w as: in, out (default low); write: high, low25 /edge ... r/w as: none, falling, rising, both26 /gpiochipN ... for each gpiochip; #N is its first GPIO27 /base ... (r/o) same as N28 /label ... (r/o) descriptive, not necessarily unique29 /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1)30 31 This ABI is obsoleted by Documentation/ABI/testing/gpio-cdev and will be32 removed after 2020.33