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gpio: ABI: mark the sysfs ABI as obsolete

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This marks the (optional) sysfs GPIO ABI as obsolete and schedules
it for removal in 2020.

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij
2015-10-22 09:58:34 +02:00
parent 40c159b776
commit fe95046e96
2 changed files with 4 additions and 1 deletions
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28
Documentation/ABI/testing/sysfs-gpio
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What: /sys/class/gpio/
Date: July 2008
KernelVersion: 2.6.27
Contact: David Brownell <dbrownell@users.sourceforge.net>
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)