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authorSven Schnelle <svens@linux.ibm.com>2026-09-09 11:29:53 +0200
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>2026-09-10 08:43:35 +0900
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selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tcgrafted
The current regex also matches symbols in modules, which makes the test fail on s390 where name_show is present only once in the kernel, but also multiple times in modules: 000001b1401cdc20 t name_show 000001b0c05e6c40 t name_show [mdev] 000001b0c0495f30 t name_show [i2c_core] Fix this by changing the regular expression to only match the function name. Link: https://lore.kernel.org/all/20260909092954.2200558-1-svens@linux.ibm.com/ Fixes: 03b80ff8023a ("selftests/ftrace: Add new test case which checks non unique symbol") Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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+.. SPDX-License-Identifier: GPL-2.0-only
+.. Copyright 2024 Linaro Ltd.
+
+====================
+Power Sequencing API
+====================
+
+:Author: Bartosz Golaszewski
+
+Introduction
+============
+
+This framework is designed to abstract complex power-up sequences that are
+shared between multiple logical devices in the Linux kernel.
+
+The intention is to allow consumers to obtain a power sequencing handle
+exposed by the power sequence provider and delegate the actual requesting and
+control of the underlying resources as well as to allow the provider to
+mitigate any potential conflicts between multiple users behind the scenes.
+
+Glossary
+--------
+
+The power sequencing API uses a number of terms specific to the subsystem:
+
+Unit
+
+ A unit is a discrete chunk of a power sequence. For instance one unit may
+ enable a set of regulators, another may enable a specific GPIO. Units can
+ define dependencies in the form of other units that must be enabled before
+ it itself can be.
+
+Target
+
+ A target is a set of units (composed of the "final" unit and its
+ dependencies) that a consumer selects by its name when requesting a handle
+ to the power sequencer. Via the dependency system, multiple targets may
+ share the same parts of a power sequence but ignore parts that are
+ irrelevant.
+
+Descriptor
+
+ A handle passed by the pwrseq core to every consumer that serves as the
+ entry point to the provider layer. It ensures coherence between different
+ users and keeps reference counting consistent.
+
+Consumer interface
+==================
+
+The consumer API is aimed to be as simple as possible. The driver interested in
+getting a descriptor from the power sequencer should call pwrseq_get() and
+specify the name of the target it wants to reach in the sequence after calling
+pwrseq_enable(). The descriptor can be released by calling pwrseq_put() and
+the consumer can request the powering down of its target with
+pwrseq_disable(). Note that there is no guarantee that pwrseq_disable()
+will have any effect as there may be multiple users of the underlying resources
+who may keep them active.
+
+Provider interface
+==================
+
+The provider API is admittedly not nearly as straightforward as the one for
+consumers but it makes up for it in flexibility.
+
+Each provider can logically split the power-up sequence into discrete chunks
+(units) and define their dependencies. They can then expose named targets that
+consumers may use as the final point in the sequence that they wish to reach.
+
+To that end the providers fill out a set of configuration structures and
+register with the pwrseq subsystem by calling pwrseq_device_register().
+
+Dynamic consumer matching
+-------------------------
+
+The main difference between pwrseq and other Linux kernel providers is the
+mechanism for dynamic matching of consumers and providers. Every power sequence
+provider driver must implement the `match()` callback and pass it to the pwrseq
+core when registering with the subsystems.
+
+When a client requests a sequencer handle, the core will call this callback for
+every registered provider and let it flexibly figure out whether the proposed
+client device is indeed its consumer. For example: if the provider binds to the
+device-tree node representing a power management unit of a chipset and the
+consumer driver controls one of its modules, the provider driver may parse the
+relevant regulator supply properties in device tree and see if they lead from
+the PMU to the consumer.
+
+API reference
+=============
+
+.. kernel-doc:: include/linux/pwrseq/provider.h
+ :internal:
+
+.. kernel-doc:: drivers/power/sequencing/core.c
+ :export: