Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst
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It is a usual pattern in the kernel to make releasing functions be NULL-aware
so they become a no-op. This helps reducing unneeded checks in the code where
the given resource is optional.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260327102729.797254-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Lee Jones <lee@kernel.org>
In preparation to class_find_device_by_of_node() going away switch to
using class_find_device_by_fwnode().
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://patch.msgid.link/20260322-remove-device-find-by-of-node-v1-5-b72eb22a1215@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
OF_GPIO is selected automatically on all OF systems. Any symbols it
controls also provide stubs so there's really no reason to select it
explicitly.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260316-gpio-of-kconfig-v2-4-de2f4b00a0e4@oss.qualcomm.com
Signed-off-by: Lee Jones <lee@kernel.org>
The mutex_lock()/mutex_unlock() pattern requires explicitly pairing
lock and unlock calls. Use guard(mutex) instead so the lock is
automatically released when the scope exits.
Convert to guard(mutex) in lm3642_torch_brightness_set(),
lm3642_strobe_brightness_set(), and lm3642_indicator_brightness_set().
Add #include <linux/cleanup.h> to support scoped guards.
Signed-off-by: Richard Lyu <richard.lyu@suse.com>
Link: https://patch.msgid.link/20260320035451.31071-1-richard.lyu@suse.com
Signed-off-by: Lee Jones <lee@kernel.org>
Fix formatting issues reported by checkpatch.pl, such as extra empty
lines, lack of braces on some branches, and misaligned function
arguments.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://patch.msgid.link/20260311-led-swnode-name-v1-2-798a49e041c6@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
If a software node defining an LED is missing explicit 'label', 'color',
or 'function' properties, led_compose_name() currently fails with
-EINVAL, because fallback to using node name in place of LED name/label
is only implemented for OF nodes.
Implement similar fallback for software nodes. Unlike OF nodes, which
use the short 'name' attribute of the device tree node to avoid
including the address block, use fwnode_get_name() directly since
swnodes do not include an address block and always have a valid name.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://patch.msgid.link/20260311-led-swnode-name-v1-1-798a49e041c6@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
Replace unused argument pinc with used argument pin.
Signed-off-by: Lukas Kraft <rebootrequired42@gmail.com>
Link: https://patch.msgid.link/20260312210958.48467-1-rebootrequired42@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>
The VIO_EN pin on the lp5860 can either be connected to VIO power supply
or GPIO.
Add the enable-gpios pin to the binding documentation.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260217-v6-19-topic-ti-lp5860-enable-gpio-v1-1-f5e8edeb5d74@pengutronix.de
Signed-off-by: Lee Jones <lee@kernel.org>
Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL
check.
Change generated with coccinelle.
Signed-off-by: Philipp Hahn <phahn-oss@avm.de>
Link: https://patch.msgid.link/20260310-b4-is_err_or_null-v1-51-bd63b656022d@avm.de
Signed-off-by: Lee Jones <lee@kernel.org>
The LED controller found in the SC2730 PMIC is compatible with the one
found in the SC2731 PMIC.
Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260222-sc27xx-mfd-cells-v1-2-69526fe74c77@abscue.de
Signed-off-by: Lee Jones <lee@kernel.org>
The EEPROM has limited writes and the contents might have factory set
values that should not be changed. The values currently written by this
driver are just one example of values, but might not be correct for many
use-cases. Do not overwrite the EEPROM with these example values every
probe.
At some point it would be better to populate the content of the EEPROM
based on a configuration provided by the user and check that the values
in EEPROM are not already the same to avoid unneeded write cycles.
That configuration would depend on how the device is used on the board to
which it is attached, for that Device Tree might be the right way. Until a
method can be devised, gate the EEPROM writing behind a module param.
Reported-by: David Owens <daowens01@gmail.com>
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://patch.msgid.link/20260305203706.841384-5-afd@ti.com
Signed-off-by: Lee Jones <lee@kernel.org>
This register is read but the contents are never checked, remove
the read until we add status checking. While here add an error
message should the preceding fault check fail.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://patch.msgid.link/20260305203706.841384-4-afd@ti.com
Signed-off-by: Lee Jones <lee@kernel.org>
The lock is taken while unlocking the EEPROM but then released, it should
instead be held for the whole EEPROM programming process. To do this
merge in the lp8860_unlock_eeprom() function to the only call site in
the lp8860_init() function. This way we hold the lock for all steps.
While here, rename this function to lp8860_program_eeprom() to better
represent what it really does.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://patch.msgid.link/20260305203706.841384-3-afd@ti.com
Signed-off-by: Lee Jones <lee@kernel.org>
No need to use goto to jump to a label that also just returns,
return directly in the if statements.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://patch.msgid.link/20260305203706.841384-2-afd@ti.com
Signed-off-by: Lee Jones <lee@kernel.org>
Instead of a regmap table each for the normal registers and the EEPROM
registers, make one table and use an access table to prevent read/write
to/from the registers between the two ranges. Slightly simplifies the
code.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://patch.msgid.link/20260305203706.841384-1-afd@ti.com
Signed-off-by: Lee Jones <lee@kernel.org>
Remove duplicate assignment of priv->mmap in intel_sso_led_probe().
Fixes: fba8a6f2263b ("leds: lgm-sso: Fix clock handling")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://patch.msgid.link/20260226033048.3715915-1-nichen@iscas.ac.cn
Signed-off-by: Lee Jones <lee@kernel.org>