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path: root/Documentation/gpio/sysfs.txt
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2015-10-11Typo correction for description in gpio document.Sachin Pandhare
Corrected Documentation/gpio/sysfs.txt for typos and wording. typos: syfs -> sysfs, manges -> manages wording: entry -> entries Signed-off-by: Sachin Pandhare <sachinpandhare@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-07-21gpio: document interaction with other subsystemsLinus Walleij
Now I am very fed up with people reinventing kernel wheels in userspace "just because they can" (read, sysfs). Put in a angry blurb in sysfs doc and put in a new file with pointers to other subsystem drivers utilizing GPIOs. Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-05-12gpio: remove gpiod_sysfs_set_active_lowJohan Hovold
Remove gpiod_sysfs_set_active_low (and gpio_sysfs_set_active_low) which allowed code to change the polarity of a gpio line even after it had been exported through sysfs. Drivers should not care, and generally does not know, about gpio-line polarity which is a hardware feature that needs to be described by firmware. It is currently possible to define gpio-line polarity in device-tree and acpi firmware or using platform data. Userspace can also change the polarity through sysfs. Note that drivers using the legacy gpio interface could still use GPIOF_ACTIVE_LOW to change the polarity before exporting the gpio. There are no in-kernel users of this interface. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Harry Wei <harryxiyou@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@zh-kernel.org Cc: linux-arch@vger.kernel.org Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-11-25Documentation: gpiolib: document new interfaceAlexandre Courbot
gpiolib now exports a new descriptor-based interface which deprecates the older integer-based one. This patch documents this new interface and also takes the opportunity to brush-up the GPIO documentation a little bit. The new descriptor-based interface follows the same consumer/driver model as many other kernel subsystems (e.g. clock, regulator), so its documentation has similarly been splitted into different files. The content of the former documentation has been reused whenever it made sense; however, some of its content did not apply to the new interface anymore and have this been removed. Likewise, new sections like the mapping of GPIOs to devices have been written from scratch. The deprecated legacy-based documentation is still available, untouched, under Documentation/gpio/gpio-legacy.txt. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>