mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
docs: Convert the regulator docbook to RST
A fairly straightforward conversion to RST; the document is then added to the driver-api manual. Of course, this document has seen no substantive changes since 2008, so chances are it needs work in other areas as well. Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
parent
8a8a602fdb
commit
028f25332c
3 changed files with 171 additions and 304 deletions
|
@ -1,304 +0,0 @@
|
|||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
|
||||
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
|
||||
|
||||
<book id="regulator-api">
|
||||
<bookinfo>
|
||||
<title>Voltage and current regulator API</title>
|
||||
|
||||
<authorgroup>
|
||||
<author>
|
||||
<firstname>Liam</firstname>
|
||||
<surname>Girdwood</surname>
|
||||
<affiliation>
|
||||
<address>
|
||||
<email>lrg@slimlogic.co.uk</email>
|
||||
</address>
|
||||
</affiliation>
|
||||
</author>
|
||||
<author>
|
||||
<firstname>Mark</firstname>
|
||||
<surname>Brown</surname>
|
||||
<affiliation>
|
||||
<orgname>Wolfson Microelectronics</orgname>
|
||||
<address>
|
||||
<email>broonie@opensource.wolfsonmicro.com</email>
|
||||
</address>
|
||||
</affiliation>
|
||||
</author>
|
||||
</authorgroup>
|
||||
|
||||
<copyright>
|
||||
<year>2007-2008</year>
|
||||
<holder>Wolfson Microelectronics</holder>
|
||||
</copyright>
|
||||
<copyright>
|
||||
<year>2008</year>
|
||||
<holder>Liam Girdwood</holder>
|
||||
</copyright>
|
||||
|
||||
<legalnotice>
|
||||
<para>
|
||||
This documentation is free software; you can redistribute
|
||||
it and/or modify it under the terms of the GNU General Public
|
||||
License version 2 as published by the Free Software Foundation.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
This program is distributed in the hope that it will be
|
||||
useful, but WITHOUT ANY WARRANTY; without even the implied
|
||||
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
||||
See the GNU General Public License for more details.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
You should have received a copy of the GNU General Public
|
||||
License along with this program; if not, write to the Free
|
||||
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
||||
MA 02111-1307 USA
|
||||
</para>
|
||||
|
||||
<para>
|
||||
For more details see the file COPYING in the source
|
||||
distribution of Linux.
|
||||
</para>
|
||||
</legalnotice>
|
||||
</bookinfo>
|
||||
|
||||
<toc></toc>
|
||||
|
||||
<chapter id="intro">
|
||||
<title>Introduction</title>
|
||||
<para>
|
||||
This framework is designed to provide a standard kernel
|
||||
interface to control voltage and current regulators.
|
||||
</para>
|
||||
<para>
|
||||
The intention is to allow systems to dynamically control
|
||||
regulator power output in order to save power and prolong
|
||||
battery life. This applies to both voltage regulators (where
|
||||
voltage output is controllable) and current sinks (where current
|
||||
limit is controllable).
|
||||
</para>
|
||||
<para>
|
||||
Note that additional (and currently more complete) documentation
|
||||
is available in the Linux kernel source under
|
||||
<filename>Documentation/power/regulator</filename>.
|
||||
</para>
|
||||
|
||||
<sect1 id="glossary">
|
||||
<title>Glossary</title>
|
||||
<para>
|
||||
The regulator API uses a number of terms which may not be
|
||||
familiar:
|
||||
</para>
|
||||
<glossary>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Regulator</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
Electronic device that supplies power to other devices. Most
|
||||
regulators can enable and disable their output and some can also
|
||||
control their output voltage or current.
|
||||
</para>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Consumer</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
Electronic device which consumes power provided by a regulator.
|
||||
These may either be static, requiring only a fixed supply, or
|
||||
dynamic, requiring active management of the regulator at
|
||||
runtime.
|
||||
</para>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Power Domain</glossterm>
|
||||
<glossdef>
|
||||
<para>
|
||||
The electronic circuit supplied by a given regulator, including
|
||||
the regulator and all consumer devices. The configuration of
|
||||
the regulator is shared between all the components in the
|
||||
circuit.
|
||||
</para>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
|
||||
<glossentry>
|
||||
<glossterm>Power Management Integrated Circuit</glossterm>
|
||||
<acronym>PMIC</acronym>
|
||||
<glossdef>
|
||||
<para>
|
||||
An IC which contains numerous regulators and often also other
|
||||
subsystems. In an embedded system the primary PMIC is often
|
||||
equivalent to a combination of the PSU and southbridge in a
|
||||
desktop system.
|
||||
</para>
|
||||
</glossdef>
|
||||
</glossentry>
|
||||
</glossary>
|
||||
</sect1>
|
||||
</chapter>
|
||||
|
||||
<chapter id="consumer">
|
||||
<title>Consumer driver interface</title>
|
||||
<para>
|
||||
This offers a similar API to the kernel clock framework.
|
||||
Consumer drivers use <link
|
||||
linkend='API-regulator-get'>get</link> and <link
|
||||
linkend='API-regulator-put'>put</link> operations to acquire and
|
||||
release regulators. Functions are
|
||||
provided to <link linkend='API-regulator-enable'>enable</link>
|
||||
and <link linkend='API-regulator-disable'>disable</link> the
|
||||
regulator and to get and set the runtime parameters of the
|
||||
regulator.
|
||||
</para>
|
||||
<para>
|
||||
When requesting regulators consumers use symbolic names for their
|
||||
supplies, such as "Vcc", which are mapped into actual regulator
|
||||
devices by the machine interface.
|
||||
</para>
|
||||
<para>
|
||||
A stub version of this API is provided when the regulator
|
||||
framework is not in use in order to minimise the need to use
|
||||
ifdefs.
|
||||
</para>
|
||||
|
||||
<sect1 id="consumer-enable">
|
||||
<title>Enabling and disabling</title>
|
||||
<para>
|
||||
The regulator API provides reference counted enabling and
|
||||
disabling of regulators. Consumer devices use the <function><link
|
||||
linkend='API-regulator-enable'>regulator_enable</link></function>
|
||||
and <function><link
|
||||
linkend='API-regulator-disable'>regulator_disable</link>
|
||||
</function> functions to enable and disable regulators. Calls
|
||||
to the two functions must be balanced.
|
||||
</para>
|
||||
<para>
|
||||
Note that since multiple consumers may be using a regulator and
|
||||
machine constraints may not allow the regulator to be disabled
|
||||
there is no guarantee that calling
|
||||
<function>regulator_disable</function> will actually cause the
|
||||
supply provided by the regulator to be disabled. Consumer
|
||||
drivers should assume that the regulator may be enabled at all
|
||||
times.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="consumer-config">
|
||||
<title>Configuration</title>
|
||||
<para>
|
||||
Some consumer devices may need to be able to dynamically
|
||||
configure their supplies. For example, MMC drivers may need to
|
||||
select the correct operating voltage for their cards. This may
|
||||
be done while the regulator is enabled or disabled.
|
||||
</para>
|
||||
<para>
|
||||
The <function><link
|
||||
linkend='API-regulator-set-voltage'>regulator_set_voltage</link>
|
||||
</function> and <function><link
|
||||
linkend='API-regulator-set-current-limit'
|
||||
>regulator_set_current_limit</link>
|
||||
</function> functions provide the primary interface for this.
|
||||
Both take ranges of voltages and currents, supporting drivers
|
||||
that do not require a specific value (eg, CPU frequency scaling
|
||||
normally permits the CPU to use a wider range of supply
|
||||
voltages at lower frequencies but does not require that the
|
||||
supply voltage be lowered). Where an exact value is required
|
||||
both minimum and maximum values should be identical.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="consumer-callback">
|
||||
<title>Callbacks</title>
|
||||
<para>
|
||||
Callbacks may also be <link
|
||||
linkend='API-regulator-register-notifier'>registered</link>
|
||||
for events such as regulation failures.
|
||||
</para>
|
||||
</sect1>
|
||||
</chapter>
|
||||
|
||||
<chapter id="driver">
|
||||
<title>Regulator driver interface</title>
|
||||
<para>
|
||||
Drivers for regulator chips <link
|
||||
linkend='API-regulator-register'>register</link> the regulators
|
||||
with the regulator core, providing operations structures to the
|
||||
core. A <link
|
||||
linkend='API-regulator-notifier-call-chain'>notifier</link> interface
|
||||
allows error conditions to be reported to the core.
|
||||
</para>
|
||||
<para>
|
||||
Registration should be triggered by explicit setup done by the
|
||||
platform, supplying a <link
|
||||
linkend='API-struct-regulator-init-data'>struct
|
||||
regulator_init_data</link> for the regulator containing
|
||||
<link linkend='machine-constraint'>constraint</link> and
|
||||
<link linkend='machine-supply'>supply</link> information.
|
||||
</para>
|
||||
</chapter>
|
||||
|
||||
<chapter id="machine">
|
||||
<title>Machine interface</title>
|
||||
<para>
|
||||
This interface provides a way to define how regulators are
|
||||
connected to consumers on a given system and what the valid
|
||||
operating parameters are for the system.
|
||||
</para>
|
||||
|
||||
<sect1 id="machine-supply">
|
||||
<title>Supplies</title>
|
||||
<para>
|
||||
Regulator supplies are specified using <link
|
||||
linkend='API-struct-regulator-consumer-supply'>struct
|
||||
regulator_consumer_supply</link>. This is done at
|
||||
<link linkend='driver'>driver registration
|
||||
time</link> as part of the machine constraints.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="machine-constraint">
|
||||
<title>Constraints</title>
|
||||
<para>
|
||||
As well as defining the connections the machine interface
|
||||
also provides constraints defining the operations that
|
||||
clients are allowed to perform and the parameters that may be
|
||||
set. This is required since generally regulator devices will
|
||||
offer more flexibility than it is safe to use on a given
|
||||
system, for example supporting higher supply voltages than the
|
||||
consumers are rated for.
|
||||
</para>
|
||||
<para>
|
||||
This is done at <link linkend='driver'>driver
|
||||
registration time</link> by providing a <link
|
||||
linkend='API-struct-regulation-constraints'>struct
|
||||
regulation_constraints</link>.
|
||||
</para>
|
||||
<para>
|
||||
The constraints may also specify an initial configuration for the
|
||||
regulator in the constraints, which is particularly useful for
|
||||
use with static consumers.
|
||||
</para>
|
||||
</sect1>
|
||||
</chapter>
|
||||
|
||||
<chapter id="api">
|
||||
<title>API reference</title>
|
||||
<para>
|
||||
Due to limitations of the kernel documentation framework and the
|
||||
existing layout of the source code the entire regulator API is
|
||||
documented here.
|
||||
</para>
|
||||
!Iinclude/linux/regulator/consumer.h
|
||||
!Iinclude/linux/regulator/machine.h
|
||||
!Iinclude/linux/regulator/driver.h
|
||||
!Edrivers/regulator/core.c
|
||||
</chapter>
|
||||
</book>
|
|
@ -22,6 +22,7 @@ available subsections can be seen below.
|
|||
message-based
|
||||
sound
|
||||
frame-buffer
|
||||
regulator
|
||||
iio/index
|
||||
input
|
||||
usb
|
||||
|
|
170
Documentation/driver-api/regulator.rst
Normal file
170
Documentation/driver-api/regulator.rst
Normal file
|
@ -0,0 +1,170 @@
|
|||
.. Copyright 2007-2008 Wolfson Microelectronics
|
||||
|
||||
.. This documentation is free software; you can redistribute
|
||||
.. it and/or modify it under the terms of the GNU General Public
|
||||
.. License version 2 as published by the Free Software Foundation.
|
||||
|
||||
=================================
|
||||
Voltage and current regulator API
|
||||
=================================
|
||||
|
||||
:Author: Liam Girdwood
|
||||
:Author: Mark Brown
|
||||
|
||||
Introduction
|
||||
============
|
||||
|
||||
This framework is designed to provide a standard kernel interface to
|
||||
control voltage and current regulators.
|
||||
|
||||
The intention is to allow systems to dynamically control regulator power
|
||||
output in order to save power and prolong battery life. This applies to
|
||||
both voltage regulators (where voltage output is controllable) and
|
||||
current sinks (where current limit is controllable).
|
||||
|
||||
Note that additional (and currently more complete) documentation is
|
||||
available in the Linux kernel source under
|
||||
``Documentation/power/regulator``.
|
||||
|
||||
Glossary
|
||||
--------
|
||||
|
||||
The regulator API uses a number of terms which may not be familiar:
|
||||
|
||||
Regulator
|
||||
|
||||
Electronic device that supplies power to other devices. Most regulators
|
||||
can enable and disable their output and some can also control their
|
||||
output voltage or current.
|
||||
|
||||
Consumer
|
||||
|
||||
Electronic device which consumes power provided by a regulator. These
|
||||
may either be static, requiring only a fixed supply, or dynamic,
|
||||
requiring active management of the regulator at runtime.
|
||||
|
||||
Power Domain
|
||||
|
||||
The electronic circuit supplied by a given regulator, including the
|
||||
regulator and all consumer devices. The configuration of the regulator
|
||||
is shared between all the components in the circuit.
|
||||
|
||||
Power Management Integrated Circuit (PMIC)
|
||||
|
||||
An IC which contains numerous regulators and often also other
|
||||
subsystems. In an embedded system the primary PMIC is often equivalent
|
||||
to a combination of the PSU and southbridge in a desktop system.
|
||||
|
||||
Consumer driver interface
|
||||
=========================
|
||||
|
||||
This offers a similar API to the kernel clock framework. Consumer
|
||||
drivers use `get <#API-regulator-get>`__ and
|
||||
`put <#API-regulator-put>`__ operations to acquire and release
|
||||
regulators. Functions are provided to `enable <#API-regulator-enable>`__
|
||||
and `disable <#API-regulator-disable>`__ the regulator and to get and
|
||||
set the runtime parameters of the regulator.
|
||||
|
||||
When requesting regulators consumers use symbolic names for their
|
||||
supplies, such as "Vcc", which are mapped into actual regulator devices
|
||||
by the machine interface.
|
||||
|
||||
A stub version of this API is provided when the regulator framework is
|
||||
not in use in order to minimise the need to use ifdefs.
|
||||
|
||||
Enabling and disabling
|
||||
----------------------
|
||||
|
||||
The regulator API provides reference counted enabling and disabling of
|
||||
regulators. Consumer devices use the :c:func:`regulator_enable()` and
|
||||
:c:func:`regulator_disable()` functions to enable and disable
|
||||
regulators. Calls to the two functions must be balanced.
|
||||
|
||||
Note that since multiple consumers may be using a regulator and machine
|
||||
constraints may not allow the regulator to be disabled there is no
|
||||
guarantee that calling :c:func:`regulator_disable()` will actually
|
||||
cause the supply provided by the regulator to be disabled. Consumer
|
||||
drivers should assume that the regulator may be enabled at all times.
|
||||
|
||||
Configuration
|
||||
-------------
|
||||
|
||||
Some consumer devices may need to be able to dynamically configure their
|
||||
supplies. For example, MMC drivers may need to select the correct
|
||||
operating voltage for their cards. This may be done while the regulator
|
||||
is enabled or disabled.
|
||||
|
||||
The :c:func:`regulator_set_voltage()` and
|
||||
:c:func:`regulator_set_current_limit()` functions provide the primary
|
||||
interface for this. Both take ranges of voltages and currents, supporting
|
||||
drivers that do not require a specific value (eg, CPU frequency scaling
|
||||
normally permits the CPU to use a wider range of supply voltages at lower
|
||||
frequencies but does not require that the supply voltage be lowered). Where
|
||||
an exact value is required both minimum and maximum values should be
|
||||
identical.
|
||||
|
||||
Callbacks
|
||||
---------
|
||||
|
||||
Callbacks may also be registered for events such as regulation failures.
|
||||
|
||||
Regulator driver interface
|
||||
==========================
|
||||
|
||||
Drivers for regulator chips register the regulators with the regulator
|
||||
core, providing operations structures to the core. A notifier interface
|
||||
allows error conditions to be reported to the core.
|
||||
|
||||
Registration should be triggered by explicit setup done by the platform,
|
||||
supplying a struct :c:type:`regulator_init_data` for the regulator
|
||||
containing constraint and supply information.
|
||||
|
||||
Machine interface
|
||||
=================
|
||||
|
||||
This interface provides a way to define how regulators are connected to
|
||||
consumers on a given system and what the valid operating parameters are
|
||||
for the system.
|
||||
|
||||
Supplies
|
||||
--------
|
||||
|
||||
Regulator supplies are specified using struct
|
||||
:c:type:`regulator_consumer_supply`. This is done at driver registration
|
||||
time as part of the machine constraints.
|
||||
|
||||
Constraints
|
||||
-----------
|
||||
|
||||
As well as defining the connections the machine interface also provides
|
||||
constraints defining the operations that clients are allowed to perform
|
||||
and the parameters that may be set. This is required since generally
|
||||
regulator devices will offer more flexibility than it is safe to use on
|
||||
a given system, for example supporting higher supply voltages than the
|
||||
consumers are rated for.
|
||||
|
||||
This is done at driver registration time` by providing a
|
||||
struct :c:type:`regulation_constraints`.
|
||||
|
||||
The constraints may also specify an initial configuration for the
|
||||
regulator in the constraints, which is particularly useful for use with
|
||||
static consumers.
|
||||
|
||||
API reference
|
||||
=============
|
||||
|
||||
Due to limitations of the kernel documentation framework and the
|
||||
existing layout of the source code the entire regulator API is
|
||||
documented here.
|
||||
|
||||
.. kernel-doc:: include/linux/regulator/consumer.h
|
||||
:internal:
|
||||
|
||||
.. kernel-doc:: include/linux/regulator/machine.h
|
||||
:internal:
|
||||
|
||||
.. kernel-doc:: include/linux/regulator/driver.h
|
||||
:internal:
|
||||
|
||||
.. kernel-doc:: drivers/regulator/core.c
|
||||
:export:
|
Loading…
Reference in a new issue