kernel/linux.git/Documentation/driver-api/gpio, branch master

Documentation: gpio: update the preferred method for using software node lookup

2026-04-08T13:52:26+00:00

In its current version, the manual for converting of board files from using GPIO lookup tables to software nodes recommends leaving the software nodes representing GPIO controllers as "free-floating", not attached objects and relying on the matching of their names against the GPIO controller's name. This is an abuse of the software node API and makes it impossible to create fw_devlinks between GPIO suppliers and consumers in this case. We want to remove this behavior from GPIOLIB and to this end, work on converting all existing drivers to using "attached" software nodes. Except for a few corner-cases where board files define consumers depending on GPIO controllers described in firmware - where we need to reference a real firmware node from a software node - which requires a more complex approach, most board files can easily be converted to using propert firmware node lookup. Update the documentation to recommend attaching the GPIO chip's software nodes to the actual platform devices and show how to do it. Reviewed-by: Linus Walleij Link: https://patch.msgid.link/20260403-doc-gpio-swnodes-v2-1-c705f5897b80@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: remove machine hogs

2026-03-16T08:51:06+00:00

With no more users, remove legacy machine hog API from the kernel. Reviewed-by: Linus Walleij Reviewed-by: Andy Shevchenko Link: https://patch.msgid.link/20260309-gpio-hog-fwnode-v2-5-4e61f3dbf06a@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: Document line value semantics

2026-03-09T09:16:00+00:00

It is not clearly documented that the GPIO driver API expect the driver to get/set the physical level of the GPIO line and the consumer API will get/set the logic level. Document this in relevant places. Reported-by: David Jander Signed-off-by: Linus Walleij Link: https://patch.msgid.link/20260306-gpio-doc-levels-v1-1-19928739e400@kernel.org Signed-off-by: Bartosz Golaszewski

Documentation: gpio: pca953x: clarify interrupt source detection

2026-01-08T09:50:33+00:00

There are multiple design tradeoffs and considerations in how the PCA953x driver detects the source(s) of an interrupt. This driver supports PCAL variants with input latching, a feature that is constrained by the fact that the interrupt status and input port registers cannot be read atomically. These limits and the design decisions deserve an in-depth explanation. Update the documentation to clarify these hardware limits and describe how the driver determines pending interrupts, and how it makes use of the PCAL input latching. Signed-off-by: Ernest Van Hoecke Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20260107093125.4053468-1-ernestvanhoecke@gmail.com Signed-off-by: Bartosz Golaszewski

Documentation: gpio: add TCAL6408 and TCAL6416

2025-12-18T10:27:05+00:00

Checked datasheets, the offsets are identical to pcal6408 and pcal6416. Signed-off-by: Jan Remmet Link: https://lore.kernel.org/r/20251216-wip-jremmet-tcal6416rtw-v2-1-6516d98a9836@phytec.de Signed-off-by: Bartosz Golaszewski

Documentation: gpio: Add a compatibility and feature list for PCA953x

2025-11-19T11:07:39+00:00

I went through all the datasheets and created this note listing chip functions and register layouts. Signed-off-by: Levente Révész Signed-off-by: Andy Shevchenko Acked-by: Randy Dunlap Tested-by: Randy Dunlap Reviewed-by: Linus Walleij Reviewed-by: Bagas Sanjaya Link: https://lore.kernel.org/r/20251112224924.2091880-1-andriy.shevchenko@linux.intel.com Signed-off-by: Bartosz Golaszewski

Documentation: gpio: add documentation about using software nodes

2025-08-26T13:27:04+00:00

Introduce documentation regarding use of software nodes to describe GPIOs on legacy boards that have not been converted to device tree. Reviewed-by: Randy Dunlap Tested-by: Randy Dunlap Signed-off-by: Dmitry Torokhov Reviewed-by: Linus Walleij Link: https://lore.kernel.org/r/tnaaz2qlk5jpbonfle7uy7pb54qx6ixwuczfbkwtxxwpj7hwas@y7a2rwko3k6c Signed-off-by: Bartosz Golaszewski

Documentation: treewide: Replace remaining spinics links with lore

2025-06-21T20:20:51+00:00

Long before introduction of lore.kernel.org, people would link to LKML threads on third-party archives (here spinics.net), which in some cases can be unreliable (as these were outside of kernel.org control). Replace links to them with lore counterparts (if any). Signed-off-by: Bagas Sanjaya Reviewed-by: Simon Horman Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20250611065254.36608-2-bagasdotme@gmail.com

gpiolib-acpi: Update file references in the Documentation and MAINTAINERS

2025-05-21T09:25:24+00:00

The recent changes in the gpiolib-acpi.c need also updates in the Documentation and MAINTAINERS. Do the necessary changes here. Fixes: babb541af627 ("gpiolib: acpi: Move quirks to a separate file") Reported-by: Stephen Rothwell Closes: https://lore.kernel.org/r/20250516193436.09bdf8cc@canb.auug.org.au Reviewed-by: Randy Dunlap Tested-by: Randy Dunlap Acked-by: Ilpo Järvinen Signed-off-by: Andy Shevchenko

Merge tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

2024-07-16T00:53:24+00:00

Pull gpio updates from Bartosz Golaszewski: "The majority of added lines are two new modules: the GPIO virtual consumer module that improves our ability to add automated tests for the kernel API and the "sloppy" logic analyzer module that uses the GPIO API to implement a coarse-grained debugging tool for useful for remote development. Other than that we have the usual assortment of various driver extensions, improvements to the core GPIO code, DT-bindings and other documentation updates as well as an extension to the interrupt simulator: GPIOLIB core: - rework kfifo handling rework in the character device code - improve the labeling of GPIOs requested as interrupts and show more info on interrupt-only GPIOs in debugfs - remove unused APIs - unexport interfaces that are only used from the core GPIO code - drop the return value from gpiochip_set_desc_names() as it cannot fail - move a string array definition out of a header and into a specific compilation unit - convert the last user of gpiochip_get_desc() other than GPIO core to using a safer alternative - use array_index_nospec() where applicable New drivers: - add a "virtual GPIO consumer" module that allows requesting GPIOs from actual hardware and driving tests of the in-kernel GPIO API from user-space over debugfs - add a GPIO-based "sloppy" logic analyzer module useful for "first glance" debugging on remote boards Driver improvements: - add support for a new model to gpio-pca953x - lock GPIOs as interrupts in gpio-sim when the lines are requested as irqs via the simulator domain + some other minor improvements - improve error reporting in gpio-syscon - convert gpio-ath79 to using dynamic GPIO base and range - use pcibios_err_to_errno() for converting PCIBIOS error codes to errno vaues in gpio-amd8111 and gpio-rdc321x - allow building gpio-brcmstb for the BCM2835 architecture DT bindings: - convert DT bindings for lsi,zevio, mpc8xxx, and atmel to DT schema - document new properties for aspeed,gpio, fsl,qoriq-gpio and gpio-vf610 - document new compatibles for pca953x and fsl,qoriq-gpio Documentation: - document stricter behavior of the GPIO character device uAPI with regards to reconfiguring requested line without direction set - clarify the effect of the active-low flag on line values and edges - remove documentation for the legacy GPIO API in order to stop tempting people to use it - document the preference for using pread() for reading edge events in the sysfs API Other: - add an extended initializer to the interrupt simulator allowing to specify a number of callbacks callers can use to be notified about irqs being requested and released" * tag 'gpio-updates-for-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (41 commits) gpio: mc33880: Convert comma to semicolon gpio: virtuser: actually use the "trimmed" local variable dt-bindings: gpio: convert Atmel GPIO to json-schema gpio: virtuser: new virtual testing driver for the GPIO API dt-bindings: gpio: vf610: Allow gpio-line-names to be set gpio: sim: lock GPIOs as interrupts when they are requested genirq/irq_sim: add an extended irq_sim initializer dt-bindings: gpio: fsl,qoriq-gpio: Add compatible string fsl,ls1046a-gpio gpiolib: unexport gpiochip_get_desc() gpio: add sloppy logic analyzer using polling Documentation: gpio: Reconfiguration with unset direction (uAPI v2) Documentation: gpio: Reconfiguration with unset direction (uAPI v1) dt-bindings: gpio: fsl,qoriq-gpio: add common property gpio-line-names gpio: ath79: convert to dynamic GPIO base allocation pinctrl: da9062: replace gpiochip_get_desc() with gpio_device_get_desc() gpiolib: put gpio_suffixes in a single compilation unit Documentation: gpio: Clarify effect of active low flag on line edges Documentation: gpio: Clarify effect of active low flag on line values gpiolib: Remove data-less gpiochip_add() function gpio: sim: use devm_mutex_init() ...