kernel/linux.git/Documentation/admin-guide/gpio, branch v6.18.21

gpio: sim: allow to mark simulated lines as invalid

2025-07-09T14:48:49+00:00

Add a new line-level, boolean property to the gpio-sim configfs interface called 'valid'. It's set by default and the user can unset it to make the line be included in the standard `gpio-reserved-ranges` property when the chip is registered with GPIO core. This allows users to specify which lines should not be available for requesting as GPIOs. Link: https://lore.kernel.org/r/20250630130358.40352-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski

Documentation: gpio: document configfs interface for gpio-aggregator

2025-04-09T14:57:29+00:00

Add documentation for the newly added configfs-based interface for GPIO aggregator. Signed-off-by: Koichiro Den Link: https://lore.kernel.org/r/20250407043019.4105613-9-koichiro.den@canonical.com Signed-off-by: Bartosz Golaszewski

Fix typos in admin-guide/gpio

2025-02-21T20:27:44+00:00

Fixing typos. Signed-off-by: Maksimilijan Marosevic Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250218193822.1031-1-maksimilijan.marosevic@proton.me

gpio: virtuser: new virtual testing driver for the GPIO API

2024-07-09T07:39:54+00:00

The GPIO subsystem used to have a serious problem with undefined behavior and use-after-free bugs on hot-unplug of GPIO chips. This can be considered a corner-case by some as most GPIO controllers are enabled early in the boot process and live until the system goes down but most GPIO drivers do allow unbind over sysfs, many are loadable modules that can be (force) unloaded and there are also GPIO devices that can be dynamically detached, for instance CP2112 which is a USB GPIO expender. Bugs can be triggered both from user-space as well as by in-kernel users. We have the means of testing it from user-space via the character device but the issues manifest themselves differently in the kernel. This is a proposition of adding a new virtual driver - a configurable GPIO consumer that can be configured over configfs (similarly to gpio-sim) or described on the device-tree. This driver is aimed as a helper in spotting any regressions in hot-unplug handling in GPIOLIB. Link: https://lore.kernel.org/r/20240708142912.120570-1-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski

Documentation: gpio: move gpio-mockup into obsolete section

2024-01-22T09:49:07+00:00

The gpio-mockup has been obsoleted by the gpio-sim, so relocate its documentation into the obsolete section of the admin-guide book. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: document gpio-mockup as obsoleted by gpio-sim

2024-01-22T09:49:07+00:00

Update the gpio-mockup documentation to note that is has been obsoleted by the gpio-sim. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: capitalize GPIO in index title

2024-01-22T09:49:07+00:00

Capitalise the title of the GPIO documentation page to match other subsystems. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: add chardev v1 userspace API documentation

2024-01-22T09:49:07+00:00

Add documentation for v1 of the GPIO character device userspace API to the obsolete section of both the admin-guide and userspace-api books. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: move sysfs into an obsolete section

2024-01-22T09:49:06+00:00

The GPIO sysfs API is long obsolete, so highlight this even further by moving it into an obsolete APIs section in both the admin-guide and userspace-api books. Signed-off-by: Kent Gibson Signed-off-by: Bartosz Golaszewski

Documentation: gpio: add chardev userspace API documentation

2024-01-22T09:47:14+00:00

Add documentation for the GPIO character device userspace API. Added to the userspace-api book, but also provide a link from the admin-guide book, as historically the GPIO documentation has been there. Signed-off-by: Kent Gibson Reviewed-by: Linus Walleij Signed-off-by: Bartosz Golaszewski