mirror of
https://github.com/torvalds/linux.git
synced 2026-07-30 03:01:41 +02:00
Linux kernel source tree
be2b723d94
Merge series from Bartosz Golaszewski <brgl@bgdev.pl>: Problem statement: GPIOs are implemented as a strictly exclusive resource in the kernel but there are lots of platforms on which single pin is shared by multiple devices which don't communicate so need some way of properly sharing access to a GPIO. What we have now is the GPIOD_FLAGS_BIT_NONEXCLUSIVE flag which was introduced as a hack and doesn't do any locking or arbitration of access - it literally just hand the same GPIO descriptor to all interested users. The proposed solution is composed of three major parts: the high-level, shared GPIO proxy driver that arbitrates access to the shared pin and exposes a regular GPIO chip interface to consumers, a low-level shared GPIOLIB module that scans firmware nodes and creates auxiliary devices that attach to the proxy driver and finally a set of core GPIOLIB changes that plug the former into the GPIO lookup path. The changes are implemented in a way that allows to seamlessly compile out any code related to sharing GPIOs for systems that don't need it. The practical use-case for this are the powerdown GPIOs shared by speakers on Qualcomm db845c platform, however I have also extensively tested it using gpio-virtuser on arm64 qemu with various DT configurations. |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.