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 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 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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When creating the regulator object, associated with a consumer device,
the supply_name is string formatted into a statically sized buffer on
the stack, then strdup()'ed onto the heap.
Not only is the dance on the stack unnecessary, but when the device's
name is long we might not fit the constructed supply_name in the fixed
64 byte buffer on the stack.
One such case can be seen on the Qualcomm Rb3Gen2 board, where we find a
PCIe controller, with a PCIe switch, with a USB controller, with a USB
hub, consuming a regulator. In this example the dev->kobj.name itself is
62 characters long.
Drop the temporary buffer on the stack and kasprintf() the string
directly on the heap, both to simplify the code, and to remove the
length limitation.
Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>
Link: https://patch.msgid.link/20260211-regulator-supply-name-length-v1-1-3875541c1576@oss.qualcomm.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Sometimes, the mt6363 regulator would fail to initialize and return with
a TIMEOUT error, so add an extra instruction to wake up the bus before
issuing the commands.
Fixes: 3c36965df808 ("regulator: Add support for MediaTek MT6363 SPMI PMIC Regulators")
Signed-off-by: Adam Ford <aford173@gmail.com>
Link: https://patch.msgid.link/20260210053708.17239-4-aford173@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from André Draszik <andre.draszik@linaro.org>:
This series extends the existing S2MPG10 PMIC driver to add support for
the regulators, and adds new S2MPG11 core and regulator drivers.
The patches are kept together in one series, due to S2MPG11 and its
regulators being very similar to S2MPG10.
The Samsung S2MPG11 PMIC is a Power Management IC for mobile
applications with buck converters, various LDOs, power meters, and
additional GPIO interfaces. It typically complements an S2MPG10 PMIC in
a main/sub configuration as the sub-PMIC and both are used on the
Google Pixel 6 and 6 Pro (oriole / raven).
A DT update for Oriole / Raven to enable these is required which I will
send out separately.
The Documentation/devicetree/bindings/regulator/regulator.yaml
already states in its description that regulator-suspend-microvolt
is deprecated, but the schema did not formally mark it as such.
Add the `deprecated: true` annotation to regulator-suspend-microvolt
so that this is enforced at the schema level.
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://patch.msgid.link/20260119-regulator-binding-v1-1-e55d33b4c3e3@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Currently, GPIOs claimed by this driver for external rail control
all show up with "s2mps11-regulator" as consumer, which is not
very informative.
Switch to using the regulator name via desc->name instead, using the
device name as fallback.
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-20-3b1f9831fffd@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Mark the Raspberry Pi 7" Display 1 ATTINY based regulator
as GPIO controller, because the hardware behaves that way
in addition to being a regulator. Add fixed gpio-cells as
well.
Signed-off-by: Marek Vasut <marex@nabladev.com>
Link: https://patch.msgid.link/20260107213638.505319-1-marex@nabladev.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The S2MPG11 PMIC is a Power Management IC for mobile applications with
buck converters, various LDOs, power meters, and additional GPIO
interfaces. It typically complements an S2MPG10 PMIC in a main/sub
configuration as the sub-PMIC.
It has 12 buck, 1 buck-boost, and 15 LDO rails. Several of these can
either be controlled via software (register writes) or via external
signals, in particular by:
* input pins connected to a main processor's:
* GPIO pins
* other pins that are e.g. firmware- or power-domain-controlled
without explicit driver intervention
* a combination of input pins and register writes.
Control via input pins allows PMIC rails to be controlled by firmware,
e.g. during standby/suspend or as part of power domain handling where
otherwise that would not be possible. Additionally toggling a pin is
faster than register writes, and it also allows the PMIC to ensure that
any necessary timing requirements between rails are respected
automatically if multiple rails are to be enabled or disabled quasi
simultaneously.
This commit implements support for all these rails and control
combination.
Note1: For an externally controlled rail, the regulator_ops provide an
empty ::enable() and no ::disable() implementations, even though Linux
can not enable the rail and one might think ::enable could be NULL.
Without ops->enable(), the regulator core will assume enabling such a
rail failed, though, and in turn never add a reference to its parent
(supplier) rail. Once a different (Linux-controlled) sibling (consumer)
rail on that same parent rail gets disabled, the parent gets disabled
(cutting power to the externally controlled rail although it should
stay on), and the system will misbehave.
Note2: While external control via input pins appears to exist on other
versions of this PMIC, there is more flexibility in this version, in
particular there is a selection of input pins to choose from for each
rail (which must therefore be configured accordingly if in use),
whereas other versions don't have this flexibility.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-19-3b1f9831fffd@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
The MT6331 has a "ldo-vio28" regulator but this was missing in the
list: add it to resolve a dtbs_check warning.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20260113110000.36953-4-angelogioacchino.delregno@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Rails in the S2MPG11 share a very similar set of properties with
S2MPG10 with slight differences. Update the existing macros to allow
reuse by the upcoming S2MPG11 driver.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-18-3b1f9831fffd@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from Andreas Kemnade <andreas@kemnade.info>:
Add a driver for the TPS65185 regulator which provides the
comparatively high voltages needed for electronic paper displays.
Datasheet for the TPS65185 is at https://www.ti.com/lit/gpn/tps65185
To simplify things, include the hwmon part directly which is only
one temperature sensor and there are no other functions besides regulators
in this chip.
The upcoming S2MPG11 support needs a similar, but different version of
::set_voltage_time(). For S2MPG10, the downwards and upwards ramps for
a rail are at different offsets at the same bit positions, while for
S2MPG11 the ramps are at the same offset at different bit positions.
Refactor the existing version slightly to allow reuse.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-17-3b1f9831fffd@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
When converting to faux_device the dummy_regulator_driver was
made non-static however it isn't exported or defined anywhere
outside the file it is in. Make it static to avoid the following
sparse warning:
drivers/regulator/dummy.c:59:24: warning: symbol 'dummy_regulator_driver' was not declared. Should it be static?
Fixes: dcd2a9a5550ef556c8 ("regulator: dummy: convert to use the faux device interface")
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Link: https://patch.msgid.link/20260112154909.601987-1-ben.dooks@codethink.co.uk
Signed-off-by: Mark Brown <broonie@kernel.org>
Add a driver for the TPS65185 regulator. Implement handling of the various
gpio pins. Because the PWRUP (=enable) pin functionality can be achieved
by just using two bits instead, just ensure that it is set to a stable
value.
Implement the pair of symmetric LDOs as a single regulator because they
share a single voltage set register. As the VCOM regulator sits behind that
machinery, just define that one as a supply.
For simplicity, just add the temperature sensor (depending on external NTC)
directly.
There is a mechanism to measure some kick-back voltage during a defined EPD
operation, to calibrate the VCOM voltage setting and store that
non-volatile in the chip to be the power up default setup. That is not
implemented yet in the driver, but that also means that there is a
non-factory default value in these registers after power-up.
Tested-by: Josua Mayer <josua.mayer@jm0.eu>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Link: https://patch.msgid.link/20260102-tps65185-submit-v3-2-23bda35772f2@kemnade.info
Signed-off-by: Mark Brown <broonie@kernel.org>
The S2MPG10 PMIC is a Power Management IC for mobile applications with
buck converters, various LDOs, power meters, RTC, clock outputs, and
additional GPIO interfaces.
It has 10 buck and 31 LDO rails. Several of these can either be
controlled via software (register writes) or via external signals, in
particular by:
* one out of several input pins connected to a main processor's:
* GPIO pins
* other pins that are e.g. firmware- or power-domain-controlled
without explicit driver intervention
* a combination of input pins and register writes.
Control via input pins allows PMIC rails to be controlled by firmware,
e.g. during standby/suspend, or as part of power domain handling where
otherwise that would not be possible. Additionally toggling a pin is
faster than register writes, and it also allows the PMIC to ensure that
any necessary timing requirements between rails are respected
automatically if multiple rails are to be enabled or disabled quasi
simultaneously.
This commit implements support for all these rails and control
combinations.
Additional data needs to be stored for each regulator, e.g. the input
pin for external control, or a rail-specific ramp-rate for when
enabling a buck-rail. Therefore, probe() is updated slightly to make
that possible.
Note1: For an externally controlled rail, the regulator_ops provide an
empty ::enable() and no ::disable() implementations, even though Linux
can not enable the rail and one might think ::enable could be NULL.
Without ops->enable(), the regulator core will assume enabling such a
rail failed, though, and in turn never add a reference to its parent
(supplier) rail. Once a different (Linux-controlled) sibling (consumer)
rail on that same parent rail gets disabled, the parent gets disabled
(cutting power to the externally controlled rail although it should
stay on), and the system will misbehave.
Note2: While external control via input pins appears to exist on other
versions of this PMIC, there is more flexibility in this version, in
particular there is a selection of input pins to choose from for each
rail (which must therefore be configured accordingly if in use),
whereas other versions don't have this flexibility.
Signed-off-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260122-s2mpg1x-regulators-v7-16-3b1f9831fffd@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Merge series from André Draszik <andre.draszik@linaro.org>:
With these attached patches it becomes possible again to support
hardware designs with multiple PMICs where individual rails of each act
as required supplies for rails of the other (due to the latter being
e.g. always-on), and vice-versa.
Google Pixel 6 and 6 Pro (oriole and raven) are examples of such
designs.
Rather than returning -EPORBE_DEFER in regulator_register() when
set_machine_constraints() fails with -EPROBE_DEFER (due to missing
required supplies), we still allow rail registration and try to
reresolve supplies each time a new rail gets registered.
This is implemented using a bus (regulator bus), which allows the core
to reresolve supplies for regulators that still need them whenever new
regulators (i.e. devices) are added.
Using a bus also solves existing problems around late resolution of
supplies as mentioned in the commit message introducing that bus.
The series starts with a few bug fixes and the last two commits
implement the changes mentioned above, but do depend on the bug fixes.
Document the TPS65185. GPIO names are same as in the datasheet except for
the PWRUP pad which is described as "enable". That pin is optional because
the rising edge corresponds to setting one register bit and falling edge
to another register bit.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Link: https://patch.msgid.link/20260102-tps65185-submit-v3-1-23bda35772f2@kemnade.info
Signed-off-by: Mark Brown <broonie@kernel.org>