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-rw-r--r--Documentation/ABI/testing/sysfs-class-regulator136
-rw-r--r--Documentation/DocBook/Makefile2
-rw-r--r--Documentation/DocBook/regulator.tmpl304
3 files changed, 365 insertions, 77 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-regulator b/Documentation/ABI/testing/sysfs-class-regulator
index 3731f6f29bc..873ef1fc156 100644
--- a/Documentation/ABI/testing/sysfs-class-regulator
+++ b/Documentation/ABI/testing/sysfs-class-regulator
@@ -3,8 +3,9 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
- state. This holds the regulator output state.
+ Some regulator directories will contain a field called
+ state. This reports the regulator enable status, for
+ regulators which can report that value.
This will be one of the following strings:
@@ -18,7 +19,8 @@ Description:
'disabled' means the regulator output is OFF and is not
supplying power to the system..
- 'unknown' means software cannot determine the state.
+ 'unknown' means software cannot determine the state, or
+ the reported state is invalid.
NOTE: this field can be used in conjunction with microvolts
and microamps to determine regulator output levels.
@@ -53,9 +55,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
microvolts. This holds the regulator output voltage setting
- measured in microvolts (i.e. E-6 Volts).
+ measured in microvolts (i.e. E-6 Volts), for regulators
+ which can report that voltage.
NOTE: This value should not be used to determine the regulator
output voltage level as this value is the same regardless of
@@ -67,9 +70,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
microamps. This holds the regulator output current limit
- setting measured in microamps (i.e. E-6 Amps).
+ setting measured in microamps (i.e. E-6 Amps), for regulators
+ which can report that current.
NOTE: This value should not be used to determine the regulator
output current level as this value is the same regardless of
@@ -81,8 +85,9 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
- opmode. This holds the regulator operating mode setting.
+ Some regulator directories will contain a field called
+ opmode. This holds the current regulator operating mode,
+ for regulators which can report it.
The opmode value can be one of the following strings:
@@ -92,7 +97,7 @@ Description:
'standby'
'unknown'
- The modes are described in include/linux/regulator/regulator.h
+ The modes are described in include/linux/regulator/consumer.h
NOTE: This value should not be used to determine the regulator
output operating mode as this value is the same regardless of
@@ -104,9 +109,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
min_microvolts. This holds the minimum safe working regulator
- output voltage setting for this domain measured in microvolts.
+ output voltage setting for this domain measured in microvolts,
+ for regulators which support voltage constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no min microvolts constraint defined by
@@ -118,9 +124,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
max_microvolts. This holds the maximum safe working regulator
- output voltage setting for this domain measured in microvolts.
+ output voltage setting for this domain measured in microvolts,
+ for regulators which support voltage constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no max microvolts constraint defined by
@@ -132,10 +139,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
min_microamps. This holds the minimum safe working regulator
output current limit setting for this domain measured in
- microamps.
+ microamps, for regulators which support current constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no min microamps constraint defined by
@@ -147,10 +154,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
max_microamps. This holds the maximum safe working regulator
output current limit setting for this domain measured in
- microamps.
+ microamps, for regulators which support current constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no max microamps constraint defined by
@@ -185,7 +192,7 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
requested_microamps. This holds the total requested load
current in microamps for this regulator from all its consumer
devices.
@@ -204,125 +211,102 @@ Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_mem_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
- the system is suspended to memory.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to memory voltage defined by
- platform code.
+ the system is suspended to memory, for voltage regulators
+ implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_disk_microvolts
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_disk_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
- the system is suspended to disk.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to disk voltage defined by
- platform code.
+ the system is suspended to disk, for voltage regulators
+ implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_standby_microvolts
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_standby_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
- the system is suspended to standby.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to standby voltage defined by
- platform code.
+ the system is suspended to standby, for voltage regulators
+ implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_mem_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_mem_mode. This holds the regulator operating mode
setting for this domain when the system is suspended to
- memory.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to memory mode defined by
- platform code.
+ memory, for regulators implementing suspend mode
+ configuration constraints.
What: /sys/class/regulator/.../suspend_disk_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_disk_mode. This holds the regulator operating mode
- setting for this domain when the system is suspended to disk.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to disk mode defined by
- platform code.
+ setting for this domain when the system is suspended to disk,
+ for regulators implementing suspend mode configuration
+ constraints.
What: /sys/class/regulator/.../suspend_standby_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_standby_mode. This holds the regulator operating mode
setting for this domain when the system is suspended to
- standby.
-
- NOTE: this will return the string 'not defined' if
- the power domain has no suspend to standby mode defined by
- platform code.
+ standby, for regulators implementing suspend mode
+ configuration constraints.
What: /sys/class/regulator/.../suspend_mem_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_mem_state. This holds the regulator operating state
- when suspended to memory.
-
- This will be one of the following strings:
+ when suspended to memory, for regulators implementing suspend
+ configuration constraints.
- 'enabled'
- 'disabled'
- 'not defined'
+ This will be one of the same strings reported by
+ the "state" attribute.
What: /sys/class/regulator/.../suspend_disk_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_disk_state. This holds the regulator operating state
- when suspended to disk.
-
- This will be one of the following strings:
+ when suspended to disk, for regulators implementing
+ suspend configuration constraints.
- 'enabled'
- 'disabled'
- 'not defined'
+ This will be one of the same strings reported by
+ the "state" attribute.
What: /sys/class/regulator/.../suspend_standby_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
- Each regulator directory will contain a field called
+ Some regulator directories will contain a field called
suspend_standby_state. This holds the regulator operating
- state when suspended to standby.
-
- This will be one of the following strings:
+ state when suspended to standby, for regulators implementing
+ suspend configuration constraints.
- 'enabled'
- 'disabled'
- 'not defined'
+ This will be one of the same strings reported by
+ the "state" attribute.
diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index 0a08126d309..dc3154e4927 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -12,7 +12,7 @@ DOCBOOKS := z8530book.xml mcabook.xml \
kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
- mac80211.xml debugobjects.xml sh.xml
+ mac80211.xml debugobjects.xml sh.xml regulator.xml
###
# The build process is as follows (targets):
diff --git a/Documentation/DocBook/regulator.tmpl b/Documentation/DocBook/regulator.tmpl
new file mode 100644
index 00000000000..53f4f8d3b81
--- /dev/null
+++ b/Documentation/DocBook/regulator.tmpl
@@ -0,0 +1,304 @@
+<?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
+ reguator 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 definining the connections the machine interface
+ also provides constraints definining 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>