linux_dsm_epyc7002/Documentation/ABI/obsolete/sysfs-gpio
Mauro Carvalho Chehab ec15872daa docs: fix broken references with multiple hints
The script:
	./scripts/documentation-file-ref-check --fix

Gives multiple hints for broken references on some files.
Manually use the one that applies for some files.

Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: James Morris <james.morris@microsoft.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
2018-06-15 18:10:01 -03:00

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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 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.