Merge branch 'reg-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6

* 'reg-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
  regulator: TI bq24022 Li-Ion Charger driver
  regulator: maintainers - add maintainers for regulator framework.
  regulator: documentation - ABI
  regulator: documentation - machine
  regulator: documentation - regulator driver
  regulator: documentation - consumer interface
  regulator: documentation - overview
  regulator: core kbuild files
  regulator: regulator test harness
  regulator: add support for fixed regulators.
  regulator: regulator framework core
  regulator: fixed regulator interface
  regulator: machine driver interface
  regulator: regulator driver interface
  regulator: consumer device interface

5 files changed, 799 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-regulator b/Documentation/ABI/testing/sysfs-class-regulator
new file mode 100644
index 000000000000..79a4a75b2d2c
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-regulator
@@ -0,0 +1,315 @@
+What:           /sys/class/regulator/.../state
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                state. This holds the regulator output state.
+
+                This will be one of the following strings:
+
+                'enabled'
+                'disabled'
+                'unknown'
+
+                'enabled' means the regulator output is ON and is supplying
+                power to the system.
+
+                'disabled' means the regulator output is OFF and is not
+                supplying power to the system..
+
+                'unknown' means software cannot determine the state.
+
+                NOTE: this field can be used in conjunction with microvolts
+                and microamps to determine regulator output levels.
+
+
+What:           /sys/class/regulator/.../type
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                type. This holds the regulator type.
+
+                This will be one of the following strings:
+
+                'voltage'
+                'current'
+                'unknown'
+
+                'voltage' means the regulator output voltage can be controlled
+                by software.
+
+                'current' means the regulator output current limit can be
+                controlled by software.
+
+                'unknown' means software cannot control either voltage or
+                current limit.
+
+
+What:           /sys/class/regulator/.../microvolts
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                microvolts. This holds the regulator output voltage setting
+                measured in microvolts (i.e. E-6 Volts).
+
+                NOTE: This value should not be used to determine the regulator
+                output voltage level as this value is the same regardless of
+                whether the regulator is enabled or disabled.
+
+
+What:           /sys/class/regulator/.../microamps
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                microamps. This holds the regulator output current limit
+                setting measured in microamps (i.e. E-6 Amps).
+
+                NOTE: This value should not be used to determine the regulator
+                output current level as this value is the same regardless of
+                whether the regulator is enabled or disabled.
+
+
+What:           /sys/class/regulator/.../opmode
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                opmode. This holds the regulator operating mode setting.
+
+                The opmode value can be one of the following strings:
+
+                'fast'
+                'normal'
+                'idle'
+                'standby'
+                'unknown'
+
+                The modes are described in include/linux/regulator/regulator.h
+
+                NOTE: This value should not be used to determine the regulator
+                output operating mode as this value is the same regardless of
+                whether the regulator is enabled or disabled.
+
+
+What:           /sys/class/regulator/.../min_microvolts
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                min_microvolts. This holds the minimum safe working regulator
+                output voltage setting for this domain measured in microvolts.
+
+                NOTE: this will return the string 'constraint not defined' if
+                the power domain has no min microvolts constraint defined by
+                platform code.
+
+
+What:           /sys/class/regulator/.../max_microvolts
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                max_microvolts. This holds the maximum safe working regulator
+                output voltage setting for this domain measured in microvolts.
+
+                NOTE: this will return the string 'constraint not defined' if
+                the power domain has no max microvolts constraint defined by
+                platform code.
+
+
+What:           /sys/class/regulator/.../min_microamps
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                min_microamps. This holds the minimum safe working regulator
+                output current limit setting for this domain measured in
+                microamps.
+
+                NOTE: this will return the string 'constraint not defined' if
+                the power domain has no min microamps constraint defined by
+                platform code.
+
+
+What:           /sys/class/regulator/.../max_microamps
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                max_microamps. This holds the maximum safe working regulator
+                output current limit setting for this domain measured in
+                microamps.
+
+                NOTE: this will return the string 'constraint not defined' if
+                the power domain has no max microamps constraint defined by
+                platform code.
+
+
+What:           /sys/class/regulator/.../num_users
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                num_users. This holds the number of consumer devices that
+                have called regulator_enable() on this regulator.
+
+
+What:           /sys/class/regulator/.../requested_microamps
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory will contain a field called
+                requested_microamps. This holds the total requested load
+                current in microamps for this regulator from all its consumer
+                devices.
+
+
+What:           /sys/class/regulator/.../parent
+Date:           April 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Some regulator directories will contain a link called parent.
+                This points to the parent or supply regulator if one exists.
+
+What:           /sys/class/regulator/.../suspend_mem_microvolts
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_disk_microvolts
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_standby_microvolts
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_mem_mode
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_disk_mode
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_standby_mode
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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.
+
+What:           /sys/class/regulator/.../suspend_mem_state
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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:
+
+                'enabled'
+                'disabled'
+                'not defined'
+
+What:           /sys/class/regulator/.../suspend_disk_state
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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:
+
+                'enabled'
+                'disabled'
+                'not defined'
+
+What:           /sys/class/regulator/.../suspend_standby_state
+Date:           May 2008
+KernelVersion:  2.6.26
+Contact:        Liam Girdwood <lg@opensource.wolfsonmicro.com>
+Description:
+                Each regulator directory 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:
+
+                'enabled'
+                'disabled'
+                'not defined'
diff --git a/Documentation/power/regulator/consumer.txt b/Documentation/power/regulator/consumer.txt
new file mode 100644
index 000000000000..82b7a43aadba
--- /dev/null
+++ b/Documentation/power/regulator/consumer.txt
@@ -0,0 +1,182 @@
+Regulator Consumer Driver Interface
+===================================
+
+This text describes the regulator interface for consumer device drivers.
+Please see overview.txt for a description of the terms used in this text.
+
+
+1. Consumer Regulator Access (static & dynamic drivers)
+=======================================================
+
+A consumer driver can get access to it's supply regulator by calling :-
+
+regulator = regulator_get(dev, "Vcc");
+
+The consumer passes in it's struct device pointer and power supply ID. The core
+then finds the correct regulator by consulting a machine specific lookup table.
+If the lookup is successful then this call will return a pointer to the struct
+regulator that supplies this consumer.
+
+To release the regulator the consumer driver should call :-
+
+regulator_put(regulator);
+
+Consumers can be supplied by more than one regulator e.g. codec consumer with
+analog and digital supplies :-
+
+digital = regulator_get(dev, "Vcc");  /* digital core */
+analog = regulator_get(dev, "Avdd");  /* analog */
+
+The regulator access functions regulator_get() and regulator_put() will
+usually be called in your device drivers probe() and remove() respectively.
+
+
+2. Regulator Output Enable & Disable (static & dynamic drivers)
+====================================================================
+
+A consumer can enable it's power supply by calling:-
+
+int regulator_enable(regulator);
+
+NOTE: The supply may already be enabled before regulator_enabled() is called.
+This may happen if the consumer shares the regulator or the regulator has been
+previously enabled by bootloader or kernel board initialization code.
+
+A consumer can determine if a regulator is enabled by calling :-
+
+int regulator_is_enabled(regulator);
+
+This will return > zero when the regulator is enabled.
+
+
+A consumer can disable it's supply when no longer needed by calling :-
+
+int regulator_disable(regulator);
+
+NOTE: This may not disable the supply if it's shared with other consumers. The
+regulator will only be disabled when the enabled reference count is zero.
+
+Finally, a regulator can be forcefully disabled in the case of an emergency :-
+
+int regulator_force_disable(regulator);
+
+NOTE: this will immediately and forcefully shutdown the regulator output. All
+consumers will be powered off.
+
+
+3. Regulator Voltage Control & Status (dynamic drivers)
+======================================================
+
+Some consumer drivers need to be able to dynamically change their supply
+voltage to match system operating points. e.g. CPUfreq drivers can scale
+voltage along with frequency to save power, SD drivers may need to select the
+correct card voltage, etc.
+
+Consumers can control their supply voltage by calling :-
+
+int regulator_set_voltage(regulator, min_uV, max_uV);
+
+Where min_uV and max_uV are the minimum and maximum acceptable voltages in
+microvolts.
+
+NOTE: this can be called when the regulator is enabled or disabled. If called
+when enabled, then the voltage changes instantly, otherwise the voltage
+configuration changes and the voltage is physically set when the regulator is
+next enabled.
+
+The regulators configured voltage output can be found by calling :-
+
+int regulator_get_voltage(regulator);
+
+NOTE: get_voltage() will return the configured output voltage whether the
+regulator is enabled or disabled and should NOT be used to determine regulator
+output state. However this can be used in conjunction with is_enabled() to
+determine the regulator physical output voltage.
+
+
+4. Regulator Current Limit Control & Status (dynamic drivers)
+===========================================================
+
+Some consumer drivers need to be able to dynamically change their supply
+current limit to match system operating points. e.g. LCD backlight driver can
+change the current limit to vary the backlight brightness, USB drivers may want
+to set the limit to 500mA when supplying power.
+
+Consumers can control their supply current limit by calling :-
+
+int regulator_set_current_limit(regulator, min_uV, max_uV);
+
+Where min_uA and max_uA are the minimum and maximum acceptable current limit in
+microamps.
+
+NOTE: this can be called when the regulator is enabled or disabled. If called
+when enabled, then the current limit changes instantly, otherwise the current
+limit configuration changes and the current limit is physically set when the
+regulator is next enabled.
+
+A regulators current limit can be found by calling :-
+
+int regulator_get_current_limit(regulator);
+
+NOTE: get_current_limit() will return the current limit whether the regulator
+is enabled or disabled and should not be used to determine regulator current
+load.
+
+
+5. Regulator Operating Mode Control & Status (dynamic drivers)
+=============================================================
+
+Some consumers can further save system power by changing the operating mode of
+their supply regulator to be more efficient when the consumers operating state
+changes. e.g. consumer driver is idle and subsequently draws less current
+
+Regulator operating mode can be changed indirectly or directly.
+
+Indirect operating mode control.
+--------------------------------
+Consumer drivers can request a change in their supply regulator operating mode
+by calling :-
+
+int regulator_set_optimum_mode(struct regulator *regulator, int load_uA);
+
+This will cause the core to recalculate the total load on the regulator (based
+on all it's consumers) and change operating mode (if necessary and permitted)
+to best match the current operating load.
+
+The load_uA value can be determined from the consumers datasheet. e.g.most
+datasheets have tables showing the max current consumed in certain situations.
+
+Most consumers will use indirect operating mode control since they have no
+knowledge of the regulator or whether the regulator is shared with other
+consumers.
+
+Direct operating mode control.
+------------------------------
+Bespoke or tightly coupled drivers may want to directly control regulator
+operating mode depending on their operating point. This can be achieved by
+calling :-
+
+int regulator_set_mode(struct regulator *regulator, unsigned int mode);
+unsigned int regulator_get_mode(struct regulator *regulator);
+
+Direct mode will only be used by consumers that *know* about the regulator and
+are not sharing the regulator with other consumers.
+
+
+6. Regulator Events
+===================
+Regulators can notify consumers of external events. Events could be received by
+consumers under regulator stress or failure conditions.
+
+Consumers can register interest in regulator events by calling :-
+
+int regulator_register_notifier(struct regulator *regulator,
+                              struct notifier_block *nb);
+
+Consumers can uregister interest by calling :-
+
+int regulator_unregister_notifier(struct regulator *regulator,
+                                struct notifier_block *nb);
+
+Regulators use the kernel notifier framework to send event to thier interested
+consumers.
diff --git a/Documentation/power/regulator/machine.txt b/Documentation/power/regulator/machine.txt
new file mode 100644
index 000000000000..c9a35665cf70
--- /dev/null
+++ b/Documentation/power/regulator/machine.txt
@@ -0,0 +1,101 @@
+Regulator Machine Driver Interface
+===================================
+
+The regulator machine driver interface is intended for board/machine specific
+initialisation code to configure the regulator subsystem. Typical things that
+machine drivers would do are :-
+
+ 1. Regulator -> Device mapping.
+ 2. Regulator supply configuration.
+ 3. Power Domain constraint setting.
+
+
+
+1. Regulator -> device mapping
+==============================
+Consider the following machine :-
+
+  Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V]
+               |
+               +-> [Consumer B @ 3.3V]
+
+The drivers for consumers A & B must be mapped to the correct regulator in
+order to control their power supply. This mapping can be achieved in machine
+initialisation code by calling :-
+
+int regulator_set_device_supply(const char *regulator, struct device *dev,
+                                const char *supply);
+
+and is shown with the following code :-
+
+regulator_set_device_supply("Regulator-1", devB, "Vcc");
+regulator_set_device_supply("Regulator-2", devA, "Vcc");
+
+This maps Regulator-1 to the 'Vcc' supply for Consumer B and maps Regulator-2
+to the 'Vcc' supply for Consumer A.
+
+
+2. Regulator supply configuration.
+==================================
+Consider the following machine (again) :-
+
+  Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V]
+               |
+               +-> [Consumer B @ 3.3V]
+
+Regulator-1 supplies power to Regulator-2. This relationship must be registered
+with the core so that Regulator-1 is also enabled when Consumer A enables it's
+supply (Regulator-2).
+
+This relationship can be register with the core via :-
+
+int regulator_set_supply(const char *regulator, const char *regulator_supply);
+
+In this example we would use the following code :-
+
+regulator_set_supply("Regulator-2", "Regulator-1");
+
+Relationships can be queried by calling :-
+
+const char *regulator_get_supply(const char *regulator);
+
+
+3. Power Domain constraint setting.
+===================================
+Each power domain within a system has physical constraints on voltage and
+current. This must be defined in software so that the power domain is always
+operated within specifications.
+
+Consider the following machine (again) :-
+
+  Regulator-1 -+-> Regulator-2 --> [Consumer A @ 1.8 - 2.0V]
+               |
+               +-> [Consumer B @ 3.3V]
+
+This gives us two regulators and two power domains:
+
+                   Domain 1: Regulator-2, Consumer B.
+                   Domain 2: Consumer A.
+
+Constraints can be registered by calling :-
+
+int regulator_set_platform_constraints(const char *regulator,
+        struct regulation_constraints *constraints);
+
+The example is defined as follows :-
+
+struct regulation_constraints domain_1 = {
+        .min_uV = 3300000,
+        .max_uV = 3300000,
+        .valid_modes_mask = REGULATOR_MODE_NORMAL,
+};
+
+struct regulation_constraints domain_2 = {
+        .min_uV = 1800000,
+        .max_uV = 2000000,
+        .valid_ops_mask = REGULATOR_CHANGE_VOLTAGE,
+        .valid_modes_mask = REGULATOR_MODE_NORMAL,
+};
+
+regulator_set_platform_constraints("Regulator-1", &domain_1);
+regulator_set_platform_constraints("Regulator-2", &domain_2);
diff --git a/Documentation/power/regulator/overview.txt b/Documentation/power/regulator/overview.txt
new file mode 100644
index 000000000000..bdcb332bd7fb
--- /dev/null
+++ b/Documentation/power/regulator/overview.txt
@@ -0,0 +1,171 @@
+Linux voltage and current regulator framework
+=============================================
+
+About
+=====
+
+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).
+
+(C) 2008  Wolfson Microelectronics PLC.
+Author: Liam Girdwood <lg@opensource.wolfsonmicro.com>
+
+
+Nomenclature
+============
+
+Some terms used in this document:-
+
+  o Regulator    - Electronic device that supplies power to other devices.
+                   Most regulators can enable and disable their output whilst
+                   some can control their output voltage and or current.
+
+                   Input Voltage -> Regulator -> Output Voltage
+
+
+  o PMIC         - Power Management IC. An IC that contains numerous regulators
+                   and often contains other susbsystems.
+
+
+  o Consumer     - Electronic device that is supplied power by a regulator.
+                   Consumers can be classified into two types:-
+
+                   Static: consumer does not change it's supply voltage or
+                   current limit. It only needs to enable or disable it's
+                   power supply. It's supply voltage is set by the hardware,
+                   bootloader, firmware or kernel board initialisation code.
+
+                   Dynamic: consumer needs to change it's supply voltage or
+                   current limit to meet operation demands.
+
+
+  o Power Domain - Electronic circuit that is supplied it's input power by the
+                   output power of a regulator, switch or by another power
+                   domain.
+
+                   The supply regulator may be behind a switch(s). i.e.
+
+                   Regulator -+-> Switch-1 -+-> Switch-2 --> [Consumer A]
+                              |             |
+                              |             +-> [Consumer B], [Consumer C]
+                              |
+                              +-> [Consumer D], [Consumer E]
+
+                   That is one regulator and three power domains:
+
+                   Domain 1: Switch-1, Consumers D & E.
+                   Domain 2: Switch-2, Consumers B & C.
+                   Domain 3: Consumer A.
+
+                   and this represents a "supplies" relationship:
+
+                   Domain-1 --> Domain-2 --> Domain-3.
+
+                   A power domain may have regulators that are supplied power
+                   by other regulators. i.e.
+
+                   Regulator-1 -+-> Regulator-2 -+-> [Consumer A]
+                                |
+                                +-> [Consumer B]
+
+                   This gives us two regulators and two power domains:
+
+                   Domain 1: Regulator-2, Consumer B.
+                   Domain 2: Consumer A.
+
+                   and a "supplies" relationship:
+
+                   Domain-1 --> Domain-2
+
+
+  o Constraints  - Constraints are used to define power levels for performance
+                   and hardware protection. Constraints exist at three levels:
+
+                   Regulator Level: This is defined by the regulator hardware
+                   operating parameters and is specified in the regulator
+                   datasheet. i.e.
+
+                     - voltage output is in the range 800mV -> 3500mV.
+                     - regulator current output limit is 20mA @ 5V but is
+                       10mA @ 10V.
+
+                   Power Domain Level: This is defined in software by kernel
+                   level board initialisation code. It is used to constrain a
+                   power domain to a particular power range. i.e.
+
+                     - Domain-1 voltage is 3300mV
+                     - Domain-2 voltage is 1400mV -> 1600mV
+                     - Domain-3 current limit is 0mA -> 20mA.
+
+                   Consumer Level: This is defined by consumer drivers
+                   dynamically setting voltage or current limit levels.
+
+                   e.g. a consumer backlight driver asks for a current increase
+                   from 5mA to 10mA to increase LCD illumination. This passes
+                   to through the levels as follows :-
+
+                   Consumer: need to increase LCD brightness. Lookup and
+                   request next current mA value in brightness table (the
+                   consumer driver could be used on several different
+                   personalities based upon the same reference device).
+
+                   Power Domain: is the new current limit within the domain
+                   operating limits for this domain and system state (e.g.
+                   battery power, USB power)
+
+                   Regulator Domains: is the new current limit within the
+                   regulator operating parameters for input/ouput voltage.
+
+                   If the regulator request passes all the constraint tests
+                   then the new regulator value is applied.
+
+
+Design
+======
+
+The framework is designed and targeted at SoC based devices but may also be
+relevant to non SoC devices and is split into the following four interfaces:-
+
+
+   1. Consumer driver interface.
+
+      This uses a similar API to the kernel clock interface in that consumer
+      drivers can get and put a regulator (like they can with clocks atm) and
+      get/set voltage, current limit, mode, enable and disable. This should
+      allow consumers complete control over their supply voltage and current
+      limit. This also compiles out if not in use so drivers can be reused in
+      systems with no regulator based power control.
+
+        See Documentation/power/regulator/consumer.txt
+
+   2. Regulator driver interface.
+
+      This allows regulator drivers to register their regulators and provide
+      operations to the core. It also has a notifier call chain for propagating
+      regulator events to clients.
+
+        See Documentation/power/regulator/regulator.txt
+
+   3. Machine interface.
+
+      This interface is for machine specific code and allows the creation of
+      voltage/current domains (with constraints) for each regulator. It can
+      provide regulator constraints that will prevent device damage through
+      overvoltage or over current caused by buggy client drivers. It also
+      allows the creation of a regulator tree whereby some regulators are
+      supplied by others (similar to a clock tree).
+
+        See Documentation/power/regulator/machine.txt
+
+   4. Userspace ABI.
+
+      The framework also exports a lot of useful voltage/current/opmode data to
+      userspace via sysfs. This could be used to help monitor device power
+      consumption and status.
+
+        See Documentation/ABI/testing/regulator-sysfs.txt
diff --git a/Documentation/power/regulator/regulator.txt b/Documentation/power/regulator/regulator.txt
new file mode 100644
index 000000000000..a69050143592
--- /dev/null
+++ b/Documentation/power/regulator/regulator.txt
@@ -0,0 +1,30 @@
+Regulator Driver Interface
+==========================
+
+The regulator driver interface is relatively simple and designed to allow
+regulator drivers to register their services with the core framework.
+
+
+Registration
+============
+
+Drivers can register a regulator by calling :-
+
+struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
+                                          void *reg_data);
+
+This will register the regulators capabilities and operations the regulator
+core. The core does not touch reg_data (private to regulator driver).
+
+Regulators can be unregistered by calling :-
+
+void regulator_unregister(struct regulator_dev *rdev);
+
+
+Regulator Events
+================
+Regulators can send events (e.g. over temp, under voltage, etc) to consumer
+drivers by calling :-
+
+int regulator_notifier_call_chain(struct regulator_dev *rdev,
+                                  unsigned long event, void *data);