31 lines
1.3 KiB
Plaintext
31 lines
1.3 KiB
Plaintext
|
What: /sys/class/gpio/
|
||
|
|
Date: July 2008
|
||
|
|
KernelVersion: 2.6.27
|
||
|
|
Contact: Linus Walleij <linusw@kernel.org>
|
||
|
|
Description:
|
||
|
|
|
||
|
|
As a Kconfig option, individual GPIO signals may be accessed from
|
||
|
|
userspace. GPIOs are only made available to userspace by an explicit
|
||
|
|
"export" operation. If a given GPIO is not claimed for use by
|
||
|
|
kernel code, it may be exported by userspace (and unexported later).
|
||
|
|
Kernel code may export it for complete or partial access.
|
||
|
|
|
||
|
|
GPIOs are identified as they are inside the kernel, using integers in
|
||
|
|
the range 0..INT_MAX. See Documentation/gpio.txt for more information.
|
||
|
|
|
||
|
|
/sys/class/gpio
|
||
|
|
/export ... asks the kernel to export a GPIO to userspace
|
||
|
|
/unexport ... to return a GPIO to the kernel
|
||
|
|
/gpioN ... for each exported GPIO #N OR
|
||
|
|
/<LINE-NAME> ... for a properly named GPIO line
|
||
|
|
/value ... always readable, writes fail for input GPIOs
|
||
|
|
/direction ... r/w as: in, out (default low); write: high, low
|
||
|
|
/edge ... r/w as: none, falling, rising, both
|
||
|
|
/gpiochipN ... for each gpiochip; #N is its first GPIO
|
||
|
|
/base ... (r/o) same as N
|
||
|
|
/label ... (r/o) descriptive, not necessarily unique
|
||
|
|
/ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1)
|
||
|
|
|
||
|
|
This ABI is deprecated and will be removed after 2020. It is
|
||
|
|
replaced with the GPIO character device.
|