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 and put operations to acquire and release regulators. Functions are provided to enable and 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 regulator_enable() and 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 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 regulator_set_voltage() and 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 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 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 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.

struct pre_voltage_change_data

Data sent with PRE_VOLTAGE_CHANGE event

Definition

struct pre_voltage_change_data {
  unsigned long old_uV;
  unsigned long min_uV;
  unsigned long max_uV;
};

Members

old_uV

Current voltage before change.

min_uV

Min voltage we’ll change to.

max_uV

Max voltage we’ll change to.

struct regulator_bulk_data

Data used for bulk regulator operations.

Definition

struct regulator_bulk_data {
  const char *supply;
  struct regulator *consumer;
};

Members

supply

The name of the supply. Initialised by the user before using the bulk regulator APIs.

consumer

The regulator consumer for the supply. This will be managed by the bulk API.

Description

The regulator APIs provide a series of regulator_bulk_() API calls as a convenience to consumers which require multiple supplies. This structure is used to manage data for these calls.

struct regulator_state

regulator state during low power system states

Definition

struct regulator_state {
  int uV;
  int min_uV;
  int max_uV;
  unsigned int mode;
  int enabled;
  bool changeable;
};

Members

uV

Default operating voltage during suspend, it can be adjusted among <min_uV, max_uV>.

min_uV

Minimum suspend voltage may be set.

max_uV

Maximum suspend voltage may be set.

mode

Operating mode during suspend.

enabled

operations during suspend. - DO_NOTHING_IN_SUSPEND - DISABLE_IN_SUSPEND - ENABLE_IN_SUSPEND

changeable

Is this state can be switched between enabled/disabled,

Description

This describes a regulators state during a system wide low power state. One of enabled or disabled must be set for the configuration to be applied.

struct regulation_constraints

regulator operating constraints.

Definition

struct regulation_constraints {
  const char *name;
  int min_uV;
  int max_uV;
  int uV_offset;
  int min_uA;
  int max_uA;
  int ilim_uA;
  int system_load;
  u32 *max_spread;
  int max_uV_step;
  unsigned int valid_modes_mask;
  unsigned int valid_ops_mask;
  int input_uV;
  struct regulator_state state_disk;
  struct regulator_state state_mem;
  struct regulator_state state_standby;
  suspend_state_t initial_state;
  unsigned int initial_mode;
  unsigned int ramp_delay;
  unsigned int settling_time;
  unsigned int settling_time_up;
  unsigned int settling_time_down;
  unsigned int enable_time;
  unsigned int active_discharge;
  unsigned always_on:1;
  unsigned boot_on:1;
  unsigned apply_uV:1;
  unsigned ramp_disable:1;
  unsigned soft_start:1;
  unsigned pull_down:1;
  unsigned over_current_protection:1;
};

Members

name

Descriptive name for the constraints, used for display purposes.

min_uV

Smallest voltage consumers may set.

max_uV

Largest voltage consumers may set.

uV_offset

Offset applied to voltages from consumer to compensate for voltage drops.

min_uA

Smallest current consumers may set.

max_uA

Largest current consumers may set.

ilim_uA

Maximum input current.

system_load

Load that isn’t captured by any consumer requests.

max_spread

Max possible spread between coupled regulators

valid_modes_mask

Mask of modes which may be configured by consumers.

valid_ops_mask

Operations which may be performed by consumers.

input_uV

Input voltage for regulator when supplied by another regulator.

state_disk

State for regulator when system is suspended in disk mode.

state_mem

State for regulator when system is suspended in mem mode.

state_standby

State for regulator when system is suspended in standby mode.

initial_state

Suspend state to set by default.

initial_mode

Mode to set at startup.

ramp_delay

Time to settle down after voltage change (unit: uV/us)

settling_time

Time to settle down after voltage change when voltage change is non-linear (unit: microseconds).

settling_time_up

Time to settle down after voltage increase when voltage change is non-linear (unit: microseconds).

settling_time_down

Time to settle down after voltage decrease when voltage change is non-linear (unit: microseconds).

enable_time

Turn-on time of the rails (unit: microseconds)

active_discharge

Enable/disable active discharge. The enum regulator_active_discharge values are used for initialisation.

always_on

Set if the regulator should never be disabled.

boot_on

Set if the regulator is enabled when the system is initially started. If the regulator is not enabled by the hardware or bootloader then it will be enabled when the constraints are applied.

apply_uV

Apply the voltage constraint when initialising.

ramp_disable

Disable ramp delay when initialising or when setting voltage.

soft_start

Enable soft start so that voltage ramps slowly.

pull_down

Enable pull down when regulator is disabled.

over_current_protection

Auto disable on over current event.

Description

This struct describes regulator and board/machine specific constraints.

struct regulator_consumer_supply

supply -> device mapping

Definition

struct regulator_consumer_supply {
  const char *dev_name;
  const char *supply;
};

Members

dev_name

Result of dev_name() for the consumer.

supply

Name for the supply.

Description

This maps a supply name to a device. Use of dev_name allows support for buses which make struct device available late such as I2C.

struct regulator_init_data

regulator platform initialisation data.

Definition

struct regulator_init_data {
  const char *supply_regulator;
  struct regulation_constraints constraints;
  int num_consumer_supplies;
  struct regulator_consumer_supply *consumer_supplies;
  int (*regulator_init)(void *driver_data);
  void *driver_data;
};

Members

supply_regulator

Parent regulator. Specified using the regulator name as it appears in the name field in sysfs, which can be explicitly set using the constraints field ‘name’.

constraints

Constraints. These must be specified for the regulator to be usable.

num_consumer_supplies

Number of consumer device supplies.

consumer_supplies

Consumer device supply configuration.

regulator_init

Callback invoked when the regulator has been registered.

driver_data

Data passed to regulator_init.

Description

Initialisation constraints, our supply and consumers supplies.

struct regulator_linear_range

specify linear voltage ranges

Definition

struct regulator_linear_range {
  unsigned int min_uV;
  unsigned int min_sel;
  unsigned int max_sel;
  unsigned int uV_step;
};

Members

min_uV

Lowest voltage in range

min_sel

Lowest selector for range

max_sel

Highest selector for range

uV_step

Step size

Description

Specify a range of voltages for regulator_map_linear_range() and regulator_list_linear_range().

struct regulator_ops

regulator operations.

Definition

struct regulator_ops {
  int (*list_voltage) (struct regulator_dev *, unsigned selector);
  int (*set_voltage) (struct regulator_dev *, int min_uV, int max_uV, unsigned *selector);
  int (*map_voltage)(struct regulator_dev *, int min_uV, int max_uV);
  int (*set_voltage_sel) (struct regulator_dev *, unsigned selector);
  int (*get_voltage) (struct regulator_dev *);
  int (*get_voltage_sel) (struct regulator_dev *);
  int (*set_current_limit) (struct regulator_dev *, int min_uA, int max_uA);
  int (*get_current_limit) (struct regulator_dev *);
  int (*set_input_current_limit) (struct regulator_dev *, int lim_uA);
  int (*set_over_current_protection) (struct regulator_dev *);
  int (*set_active_discharge) (struct regulator_dev *, bool enable);
  int (*enable) (struct regulator_dev *);
  int (*disable) (struct regulator_dev *);
  int (*is_enabled) (struct regulator_dev *);
  int (*set_mode) (struct regulator_dev *, unsigned int mode);
  unsigned int (*get_mode) (struct regulator_dev *);
  int (*get_error_flags)(struct regulator_dev *, unsigned int *flags);
  int (*enable_time) (struct regulator_dev *);
  int (*set_ramp_delay) (struct regulator_dev *, int ramp_delay);
  int (*set_voltage_time) (struct regulator_dev *, int old_uV, int new_uV);
  int (*set_voltage_time_sel) (struct regulator_dev *,unsigned int old_selector, unsigned int new_selector);
  int (*set_soft_start) (struct regulator_dev *);
  int (*get_status)(struct regulator_dev *);
  unsigned int (*get_optimum_mode) (struct regulator_dev *, int input_uV, int output_uV, int load_uA);
  int (*set_load)(struct regulator_dev *, int load_uA);
  int (*set_bypass)(struct regulator_dev *dev, bool enable);
  int (*get_bypass)(struct regulator_dev *dev, bool *enable);
  int (*set_suspend_voltage) (struct regulator_dev *, int uV);
  int (*set_suspend_enable) (struct regulator_dev *);
  int (*set_suspend_disable) (struct regulator_dev *);
  int (*set_suspend_mode) (struct regulator_dev *, unsigned int mode);
  int (*resume)(struct regulator_dev *rdev);
  int (*set_pull_down) (struct regulator_dev *);
};

Members

list_voltage

Return one of the supported voltages, in microvolts; zero if the selector indicates a voltage that is unusable on this system; or negative errno. Selectors range from zero to one less than regulator_desc.n_voltages. Voltages may be reported in any order.

set_voltage

Set the voltage for the regulator within the range specified. The driver should select the voltage closest to min_uV.

map_voltage

Convert a voltage into a selector

set_voltage_sel

Set the voltage for the regulator using the specified selector.

get_voltage

Return the currently configured voltage for the regulator; return -ENOTRECOVERABLE if regulator can’t be read at bootup and hasn’t been set yet.

get_voltage_sel

Return the currently configured voltage selector for the regulator; return -ENOTRECOVERABLE if regulator can’t be read at bootup and hasn’t been set yet.

set_current_limit

Configure a limit for a current-limited regulator. The driver should select the current closest to max_uA.

get_current_limit

Get the configured limit for a current-limited regulator.

set_input_current_limit

Configure an input limit.

set_over_current_protection

Support capability of automatically shutting down when detecting an over current event.

set_active_discharge

Set active discharge enable/disable of regulators.

enable

Configure the regulator as enabled.

disable

Configure the regulator as disabled.

is_enabled

Return 1 if the regulator is enabled, 0 if not. May also return negative errno.

set_mode

Set the configured operating mode for the regulator.

get_mode

Get the configured operating mode for the regulator.

get_error_flags

Get the current error(s) for the regulator.

enable_time

Time taken for the regulator voltage output voltage to stabilise after being enabled, in microseconds.

set_ramp_delay

Set the ramp delay for the regulator. The driver should select ramp delay equal to or less than(closest) ramp_delay.

set_voltage_time

Time taken for the regulator voltage output voltage to stabilise after being set to a new value, in microseconds. The function receives the from and to voltage as input, it should return the worst case.

set_voltage_time_sel

Time taken for the regulator voltage output voltage to stabilise after being set to a new value, in microseconds. The function receives the from and to voltage selector as input, it should return the worst case.

set_soft_start

Enable soft start for the regulator.

get_status

Return actual (not as-configured) status of regulator, as a REGULATOR_STATUS value (or negative errno)

get_optimum_mode

Get the most efficient operating mode for the regulator when running with the specified parameters.

set_load

Set the load for the regulator.

set_bypass

Set the regulator in bypass mode.

get_bypass

Get the regulator bypass mode state.

set_suspend_voltage

Set the voltage for the regulator when the system is suspended.

set_suspend_enable

Mark the regulator as enabled when the system is suspended.

set_suspend_disable

Mark the regulator as disabled when the system is suspended.

set_suspend_mode

Set the operating mode for the regulator when the system is suspended.

set_pull_down

Configure the regulator to pull down when the regulator is disabled.

Description

This struct describes regulator operations which can be implemented by regulator chip drivers.

struct regulator_desc

Static regulator descriptor

Definition

struct regulator_desc {
  const char *name;
  const char *supply_name;
  const char *of_match;
  const char *regulators_node;
  int (*of_parse_cb)(struct device_node *,const struct regulator_desc *, struct regulator_config *);
  int id;
  unsigned int continuous_voltage_range:1;
  unsigned n_voltages;
  unsigned int n_current_limits;
  const struct regulator_ops *ops;
  int irq;
  enum regulator_type type;
  struct module *owner;
  unsigned int min_uV;
  unsigned int uV_step;
  unsigned int linear_min_sel;
  int fixed_uV;
  unsigned int ramp_delay;
  int min_dropout_uV;
  const struct regulator_linear_range *linear_ranges;
  const unsigned int *linear_range_selectors;
  int n_linear_ranges;
  const unsigned int *volt_table;
  const unsigned int *curr_table;
  unsigned int vsel_range_reg;
  unsigned int vsel_range_mask;
  unsigned int vsel_reg;
  unsigned int vsel_mask;
  unsigned int vsel_step;
  unsigned int csel_reg;
  unsigned int csel_mask;
  unsigned int apply_reg;
  unsigned int apply_bit;
  unsigned int enable_reg;
  unsigned int enable_mask;
  unsigned int enable_val;
  unsigned int disable_val;
  bool enable_is_inverted;
  unsigned int bypass_reg;
  unsigned int bypass_mask;
  unsigned int bypass_val_on;
  unsigned int bypass_val_off;
  unsigned int active_discharge_on;
  unsigned int active_discharge_off;
  unsigned int active_discharge_mask;
  unsigned int active_discharge_reg;
  unsigned int soft_start_reg;
  unsigned int soft_start_mask;
  unsigned int soft_start_val_on;
  unsigned int pull_down_reg;
  unsigned int pull_down_mask;
  unsigned int pull_down_val_on;
  unsigned int enable_time;
  unsigned int off_on_delay;
  unsigned int (*of_map_mode)(unsigned int mode);
};

Members

name

Identifying name for the regulator.

supply_name

Identifying the regulator supply

of_match

Name used to identify regulator in DT.

regulators_node

Name of node containing regulator definitions in DT.

of_parse_cb

Optional callback called only if of_match is present. Will be called for each regulator parsed from DT, during init_data parsing. The regulator_config passed as argument to the callback will be a copy of config passed to regulator_register, valid only for this particular call. Callback may freely change the config but it cannot store it for later usage. Callback should return 0 on success or negative ERRNO indicating failure.

id

Numerical identifier for the regulator.

continuous_voltage_range

Indicates if the regulator can set any voltage within constrains range.

n_voltages

Number of selectors available for ops.list_voltage().

n_current_limits

Number of selectors available for current limits

ops

Regulator operations table.

irq

Interrupt number for the regulator.

type

Indicates if the regulator is a voltage or current regulator.

owner

Module providing the regulator, used for refcounting.

min_uV

Voltage given by the lowest selector (if linear mapping)

uV_step

Voltage increase with each selector (if linear mapping)

linear_min_sel

Minimal selector for starting linear mapping

fixed_uV

Fixed voltage of rails.

ramp_delay

Time to settle down after voltage change (unit: uV/us)

min_dropout_uV

The minimum dropout voltage this regulator can handle

linear_ranges

A constant table of possible voltage ranges.

linear_range_selectors

A constant table of voltage range selectors. If pickable ranges are used each range must have corresponding selector here.

n_linear_ranges

Number of entries in the linear_ranges (and in linear_range_selectors if used) table(s).

volt_table

Voltage mapping table (if table based mapping)

curr_table

Current limit mapping table (if table based mapping)

vsel_range_reg

Register for range selector when using pickable ranges and regulator_regmap_X_voltage_X_pickable functions.

vsel_range_mask

Mask for register bitfield used for range selector

vsel_reg

Register for selector when using regulator_regmap_X_voltage_

vsel_mask

Mask for register bitfield used for selector

vsel_step

Specify the resolution of selector stepping when setting voltage. If 0, then no stepping is done (requested selector is set directly), if >0 then the regulator API will ramp the voltage up/down gradually each time increasing/decreasing the selector by the specified step value.

csel_reg

Register for current limit selector using regmap set_current_limit

csel_mask

Mask for register bitfield used for current limit selector

apply_reg

Register for initiate voltage change on the output when using regulator_set_voltage_sel_regmap

apply_bit

Register bitfield used for initiate voltage change on the output when using regulator_set_voltage_sel_regmap

enable_reg

Register for control when using regmap enable/disable ops

enable_mask

Mask for control when using regmap enable/disable ops

enable_val

Enabling value for control when using regmap enable/disable ops

disable_val

Disabling value for control when using regmap enable/disable ops

enable_is_inverted

A flag to indicate set enable_mask bits to disable when using regulator_enable_regmap and friends APIs.

bypass_reg

Register for control when using regmap set_bypass

bypass_mask

Mask for control when using regmap set_bypass

bypass_val_on

Enabling value for control when using regmap set_bypass

bypass_val_off

Disabling value for control when using regmap set_bypass

active_discharge_on

Disabling value for control when using regmap set_active_discharge

active_discharge_off

Enabling value for control when using regmap set_active_discharge

active_discharge_mask

Mask for control when using regmap set_active_discharge

active_discharge_reg

Register for control when using regmap set_active_discharge

soft_start_reg

Register for control when using regmap set_soft_start

soft_start_mask

Mask for control when using regmap set_soft_start

soft_start_val_on

Enabling value for control when using regmap set_soft_start

pull_down_reg

Register for control when using regmap set_pull_down

pull_down_mask

Mask for control when using regmap set_pull_down

pull_down_val_on

Enabling value for control when using regmap set_pull_down

enable_time

Time taken for initial enable of regulator (in uS).

off_on_delay

guard time (in uS), before re-enabling a regulator

of_map_mode

Maps a hardware mode defined in a DeviceTree to a standard mode

Description

Each regulator registered with the core is described with a structure of this type and a struct regulator_config. This structure contains the non-varying parts of the regulator description.

struct regulator_config

Dynamic regulator descriptor

Definition

struct regulator_config {
  struct device *dev;
  const struct regulator_init_data *init_data;
  void *driver_data;
  struct device_node *of_node;
  struct regmap *regmap;
  struct gpio_desc *ena_gpiod;
};

Members

dev

struct device for the regulator

init_data

platform provided init data, passed through by driver

driver_data

private regulator data

of_node

OpenFirmware node to parse for device tree bindings (may be NULL).

regmap

regmap to use for core regmap helpers if dev_get_regmap() is insufficient.

ena_gpiod

GPIO controlling regulator enable.

Description

Each regulator registered with the core is described with a structure of this type and a struct regulator_desc. This structure contains the runtime variable parts of the regulator description.

void regulator_lock(struct regulator_dev * rdev)

lock a single regulator

Parameters

struct regulator_dev * rdev

regulator source

Description

This function can be called many times by one task on a single regulator and its mutex will be locked only once. If a task, which is calling this function is other than the one, which initially locked the mutex, it will wait on mutex.

void regulator_unlock(struct regulator_dev * rdev)

unlock a single regulator

Parameters

struct regulator_dev * rdev

regulator_source

Description

This function unlocks the mutex when the reference counter reaches 0.

struct regulator * regulator_get(struct device * dev, const char * id)

lookup and obtain a reference to a regulator.

Parameters

struct device * dev

device for regulator “consumer”

const char * id

Supply name or regulator ID.

Description

Returns a struct regulator corresponding to the regulator producer, or IS_ERR() condition containing errno.

Use of supply names configured via regulator_set_device_supply() is strongly encouraged. It is recommended that the supply name used should match the name used for the supply and/or the relevant device pins in the datasheet.

struct regulator * regulator_get_exclusive(struct device * dev, const char * id)

obtain exclusive access to a regulator.

Parameters

struct device * dev

device for regulator “consumer”

const char * id

Supply name or regulator ID.

Description

Returns a struct regulator corresponding to the regulator producer, or IS_ERR() condition containing errno. Other consumers will be unable to obtain this regulator while this reference is held and the use count for the regulator will be initialised to reflect the current state of the regulator.

This is intended for use by consumers which cannot tolerate shared use of the regulator such as those which need to force the regulator off for correct operation of the hardware they are controlling.

Use of supply names configured via regulator_set_device_supply() is strongly encouraged. It is recommended that the supply name used should match the name used for the supply and/or the relevant device pins in the datasheet.

struct regulator * regulator_get_optional(struct device * dev, const char * id)

obtain optional access to a regulator.

Parameters

struct device * dev

device for regulator “consumer”

const char * id

Supply name or regulator ID.

Description

Returns a struct regulator corresponding to the regulator producer, or IS_ERR() condition containing errno.

This is intended for use by consumers for devices which can have some supplies unconnected in normal use, such as some MMC devices. It can allow the regulator core to provide stub supplies for other supplies requested using normal regulator_get() calls without disrupting the operation of drivers that can handle absent supplies.

Use of supply names configured via regulator_set_device_supply() is strongly encouraged. It is recommended that the supply name used should match the name used for the supply and/or the relevant device pins in the datasheet.

void regulator_put(struct regulator * regulator)

“free” the regulator source

Parameters

struct regulator * regulator

regulator source

Note

drivers must ensure that all regulator_enable calls made on this regulator source are balanced by regulator_disable calls prior to calling this function.

int regulator_register_supply_alias(struct device * dev, const char * id, struct device * alias_dev, const char * alias_id)

Provide device alias for supply lookup

Parameters

struct device * dev

device that will be given as the regulator “consumer”

const char * id

Supply name or regulator ID

struct device * alias_dev

device that should be used to lookup the supply

const char * alias_id

Supply name or regulator ID that should be used to lookup the supply

Description

All lookups for id on dev will instead be conducted for alias_id on alias_dev.

void regulator_unregister_supply_alias(struct device * dev, const char * id)

Remove device alias

Parameters

struct device * dev

device that will be given as the regulator “consumer”

const char * id

Supply name or regulator ID

Description

Remove a lookup alias if one exists for id on dev.

int regulator_bulk_register_supply_alias(struct device * dev, const char *const * id, struct device * alias_dev, const char *const * alias_id, int num_id)

register multiple aliases

Parameters

struct device * dev

device that will be given as the regulator “consumer”

const char *const * id

List of supply names or regulator IDs

struct device * alias_dev

device that should be used to lookup the supply

const char *const * alias_id

List of supply names or regulator IDs that should be used to lookup the supply

int num_id

Number of aliases to register

Description

return 0 on success, an errno on failure.

This helper function allows drivers to register several supply aliases in one operation. If any of the aliases cannot be registered any aliases that were registered will be removed before returning to the caller.

void regulator_bulk_unregister_supply_alias(struct device * dev, const char *const * id, int num_id)

unregister multiple aliases

Parameters

struct device * dev

device that will be given as the regulator “consumer”

const char *const * id

List of supply names or regulator IDs

int num_id

Number of aliases to unregister

Description

This helper function allows drivers to unregister several supply aliases in one operation.

int regulator_enable(struct regulator * regulator)

enable regulator output

Parameters

struct regulator * regulator

regulator source

Description

Request that the regulator be enabled with the regulator output at the predefined voltage or current value. Calls to regulator_enable() must be balanced with calls to regulator_disable().

NOTE

the output value can be set by other drivers, boot loader or may be hardwired in the regulator.

int regulator_disable(struct regulator * regulator)

disable regulator output

Parameters

struct regulator * regulator

regulator source

Description

Disable the regulator output voltage or current. Calls to regulator_enable() must be balanced with calls to regulator_disable().

NOTE

this will only disable the regulator output if no other consumer devices have it enabled, the regulator device supports disabling and machine constraints permit this operation.

int regulator_force_disable(struct regulator * regulator)

force disable regulator output

Parameters

struct regulator * regulator

regulator source

Description

Forcibly disable the regulator output voltage or current.

NOTE

this will disable the regulator output even if other consumer devices have it enabled. This should be used for situations when device damage will likely occur if the regulator is not disabled (e.g. over temp).

int regulator_disable_deferred(struct regulator * regulator, int ms)

disable regulator output with delay

Parameters

struct regulator * regulator

regulator source

int ms

milliseconds until the regulator is disabled

Description

Execute regulator_disable() on the regulator after a delay. This is intended for use with devices that require some time to quiesce.

NOTE

this will only disable the regulator output if no other consumer devices have it enabled, the regulator device supports disabling and machine constraints permit this operation.

int regulator_is_enabled(struct regulator * regulator)

is the regulator output enabled

Parameters

struct regulator * regulator

regulator source

Description

Returns positive if the regulator driver backing the source/client has requested that the device be enabled, zero if it hasn’t, else a negative errno code.

Note that the device backing this regulator handle can have multiple users, so it might be enabled even if regulator_enable() was never called for this particular source.

int regulator_count_voltages(struct regulator * regulator)

count regulator_list_voltage() selectors

Parameters

struct regulator * regulator

regulator source

Description

Returns number of selectors, or negative errno. Selectors are numbered starting at zero, and typically correspond to bitfields in hardware registers.

int regulator_list_voltage(struct regulator * regulator, unsigned selector)

enumerate supported voltages

Parameters

struct regulator * regulator

regulator source

unsigned selector

identify voltage to list

Context

can sleep

Description

Returns a voltage that can be passed to regulator_set_voltage(), zero if this selector code can’t be used on this system, or a negative errno.

int regulator_get_hardware_vsel_register(struct regulator * regulator, unsigned * vsel_reg, unsigned * vsel_mask)

get the HW voltage selector register

Parameters

struct regulator * regulator

regulator source

unsigned * vsel_reg

voltage selector register, output parameter

unsigned * vsel_mask

mask for voltage selector bitfield, output parameter

Description

Returns the hardware register offset and bitmask used for setting the regulator voltage. This might be useful when configuring voltage-scaling hardware or firmware that can make I2C requests behind the kernel’s back, for example.

On success, the output parameters vsel_reg and vsel_mask are filled in and 0 is returned, otherwise a negative errno is returned.

int regulator_list_hardware_vsel(struct regulator * regulator, unsigned selector)

get the HW-specific register value for a selector

Parameters

struct regulator * regulator

regulator source

unsigned selector

identify voltage to list

Description

Converts the selector to a hardware-specific voltage selector that can be directly written to the regulator registers. The address of the voltage register can be determined by calling regulator_get_hardware_vsel_register.

On error a negative errno is returned.

unsigned int regulator_get_linear_step(struct regulator * regulator)

return the voltage step size between VSEL values

Parameters

struct regulator * regulator

regulator source

Description

Returns the voltage step size between VSEL values for linear regulators, or return 0 if the regulator isn’t a linear regulator.

int regulator_is_supported_voltage(struct regulator * regulator, int min_uV, int max_uV)

check if a voltage range can be supported

Parameters

struct regulator * regulator

Regulator to check.

int min_uV

Minimum required voltage in uV.

int max_uV

Maximum required voltage in uV.

Description

Returns a boolean.

int regulator_set_voltage(struct regulator * regulator, int min_uV, int max_uV)

set regulator output voltage

Parameters

struct regulator * regulator

regulator source

int min_uV

Minimum required voltage in uV

int max_uV

Maximum acceptable voltage in uV

Description

Sets a voltage regulator to the desired output voltage. This can be set during any regulator state. IOW, regulator can be disabled or enabled.

If the regulator is enabled then the voltage will change to the new value immediately otherwise if the regulator is disabled the regulator will output at the new voltage when enabled.

NOTE

If the regulator is shared between several devices then the lowest request voltage that meets the system constraints will be used. Regulator system constraints must be set for this regulator before calling this function otherwise this call will fail.

int regulator_set_voltage_time(struct regulator * regulator, int old_uV, int new_uV)

get raise/fall time

Parameters

struct regulator * regulator

regulator source

int old_uV

starting voltage in microvolts

int new_uV

target voltage in microvolts

Description

Provided with the starting and ending voltage, this function attempts to calculate the time in microseconds required to rise or fall to this new voltage.

int regulator_set_voltage_time_sel(struct regulator_dev * rdev, unsigned int old_selector, unsigned int new_selector)

get raise/fall time

Parameters

struct regulator_dev * rdev

regulator source device

unsigned int old_selector

selector for starting voltage

unsigned int new_selector

selector for target voltage

Description

Provided with the starting and target voltage selectors, this function returns time in microseconds required to rise or fall to this new voltage

Drivers providing ramp_delay in regulation_constraints can use this as their set_voltage_time_sel() operation.

int regulator_sync_voltage(struct regulator * regulator)

re-apply last regulator output voltage

Parameters

struct regulator * regulator

regulator source

Description

Re-apply the last configured voltage. This is intended to be used where some external control source the consumer is cooperating with has caused the configured voltage to change.

int regulator_get_voltage(struct regulator * regulator)

get regulator output voltage

Parameters

struct regulator * regulator

regulator source

Description

This returns the current regulator voltage in uV.

NOTE

If the regulator is disabled it will return the voltage value. This function should not be used to determine regulator state.

int regulator_set_current_limit(struct regulator * regulator, int min_uA, int max_uA)

set regulator output current limit

Parameters

struct regulator * regulator

regulator source

int min_uA

Minimum supported current in uA

int max_uA

Maximum supported current in uA

Description

Sets current sink to the desired output current. This can be set during any regulator state. IOW, regulator can be disabled or enabled.

If the regulator is enabled then the current will change to the new value immediately otherwise if the regulator is disabled the regulator will output at the new current when enabled.

NOTE

Regulator system constraints must be set for this regulator before calling this function otherwise this call will fail.

int regulator_get_current_limit(struct regulator * regulator)

get regulator output current

Parameters

struct regulator * regulator

regulator source

Description

This returns the current supplied by the specified current sink in uA.

NOTE

If the regulator is disabled it will return the current value. This function should not be used to determine regulator state.

int regulator_set_mode(struct regulator * regulator, unsigned int mode)

set regulator operating mode

Parameters

struct regulator * regulator

regulator source

unsigned int mode

operating mode - one of the REGULATOR_MODE constants

Description

Set regulator operating mode to increase regulator efficiency or improve regulation performance.

NOTE

Regulator system constraints must be set for this regulator before calling this function otherwise this call will fail.

unsigned int regulator_get_mode(struct regulator * regulator)

get regulator operating mode

Parameters

struct regulator * regulator

regulator source

Description

Get the current regulator operating mode.

int regulator_get_error_flags(struct regulator * regulator, unsigned int * flags)

get regulator error information

Parameters

struct regulator * regulator

regulator source

unsigned int * flags

pointer to store error flags

Description

Get the current regulator error information.

int regulator_set_load(struct regulator * regulator, int uA_load)

set regulator load

Parameters

struct regulator * regulator

regulator source

int uA_load

load current

Description

Notifies the regulator core of a new device load. This is then used by DRMS (if enabled by constraints) to set the most efficient regulator operating mode for the new regulator loading.

Consumer devices notify their supply regulator of the maximum power they will require (can be taken from device datasheet in the power consumption tables) when they change operational status and hence power state. Examples of operational state changes that can affect power consumption are :-

o Device is opened / closed. o Device I/O is about to begin or has just finished. o Device is idling in between work.

This information is also exported via sysfs to userspace.

DRMS will sum the total requested load on the regulator and change to the most efficient operating mode if platform constraints allow.

NOTE

when a regulator consumer requests to have a regulator disabled then any load that consumer requested no longer counts toward the total requested load. If the regulator is re-enabled then the previously requested load will start counting again.

If a regulator is an always-on regulator then an individual consumer’s load will still be removed if that consumer is fully disabled.

On error a negative errno is returned.

int regulator_allow_bypass(struct regulator * regulator, bool enable)

allow the regulator to go into bypass mode

Parameters

struct regulator * regulator

Regulator to configure

bool enable

enable or disable bypass mode

Description

Allow the regulator to go into bypass mode if all other consumers for the regulator also enable bypass mode and the machine constraints allow this. Bypass mode means that the regulator is simply passing the input directly to the output with no regulation.

int regulator_register_notifier(struct regulator * regulator, struct notifier_block * nb)

register regulator event notifier

Parameters

struct regulator * regulator

regulator source

struct notifier_block * nb

notifier block

Description

Register notifier block to receive regulator events.

int regulator_unregister_notifier(struct regulator * regulator, struct notifier_block * nb)

unregister regulator event notifier

Parameters

struct regulator * regulator

regulator source

struct notifier_block * nb

notifier block

Description

Unregister regulator event notifier block.

int regulator_bulk_get(struct device * dev, int num_consumers, struct regulator_bulk_data * consumers)

get multiple regulator consumers

Parameters

struct device * dev

Device to supply

int num_consumers

Number of consumers to register

struct regulator_bulk_data * consumers

Configuration of consumers; clients are stored here.

Description

return 0 on success, an errno on failure.

This helper function allows drivers to get several regulator consumers in one operation. If any of the regulators cannot be acquired then any regulators that were allocated will be freed before returning to the caller.

int regulator_bulk_enable(int num_consumers, struct regulator_bulk_data * consumers)

enable multiple regulator consumers

Parameters

int num_consumers

Number of consumers

struct regulator_bulk_data * consumers

Consumer data; clients are stored here. return 0 on success, an errno on failure

Description

This convenience API allows consumers to enable multiple regulator clients in a single API call. If any consumers cannot be enabled then any others that were enabled will be disabled again prior to return.

int regulator_bulk_disable(int num_consumers, struct regulator_bulk_data * consumers)

disable multiple regulator consumers

Parameters

int num_consumers

Number of consumers

struct regulator_bulk_data * consumers

Consumer data; clients are stored here. return 0 on success, an errno on failure

Description

This convenience API allows consumers to disable multiple regulator clients in a single API call. If any consumers cannot be disabled then any others that were disabled will be enabled again prior to return.

int regulator_bulk_force_disable(int num_consumers, struct regulator_bulk_data * consumers)

force disable multiple regulator consumers

Parameters

int num_consumers

Number of consumers

struct regulator_bulk_data * consumers

Consumer data; clients are stored here. return 0 on success, an errno on failure

Description

This convenience API allows consumers to forcibly disable multiple regulator clients in a single API call.

NOTE

This should be used for situations when device damage will likely occur if the regulators are not disabled (e.g. over temp). Although regulator_force_disable function call for some consumers can return error numbers, the function is called for all consumers.

void regulator_bulk_free(int num_consumers, struct regulator_bulk_data * consumers)

free multiple regulator consumers

Parameters

int num_consumers

Number of consumers

struct regulator_bulk_data * consumers

Consumer data; clients are stored here.

Description

This convenience API allows consumers to free multiple regulator clients in a single API call.

int regulator_notifier_call_chain(struct regulator_dev * rdev, unsigned long event, void * data)

call regulator event notifier

Parameters

struct regulator_dev * rdev

regulator source

unsigned long event

notifier block

void * data

callback-specific data.

Description

Called by regulator drivers to notify clients a regulator event has occurred. We also notify regulator clients downstream. Note lock must be held by caller.

int regulator_mode_to_status(unsigned int mode)

convert a regulator mode into a status

Parameters

unsigned int mode

Mode to convert

Description

Convert a regulator mode into a status.

struct regulator_dev * regulator_register(const struct regulator_desc * regulator_desc, const struct regulator_config * cfg)

register regulator

Parameters

const struct regulator_desc * regulator_desc

regulator to register

const struct regulator_config * cfg

runtime configuration for regulator

Description

Called by regulator drivers to register a regulator. Returns a valid pointer to struct regulator_dev on success or an ERR_PTR() on error.

void regulator_unregister(struct regulator_dev * rdev)

unregister regulator

Parameters

struct regulator_dev * rdev

regulator to unregister

Description

Called by regulator drivers to unregister a regulator.

void regulator_has_full_constraints(void)

the system has fully specified constraints

Parameters

void

no arguments

Description

Calling this function will cause the regulator API to disable all regulators which have a zero use count and don’t have an always_on constraint in a late_initcall.

The intention is that this will become the default behaviour in a future kernel release so users are encouraged to use this facility now.

void * rdev_get_drvdata(struct regulator_dev * rdev)

get rdev regulator driver data

Parameters

struct regulator_dev * rdev

regulator

Description

Get rdev regulator driver private data. This call can be used in the regulator driver context.

void * regulator_get_drvdata(struct regulator * regulator)

get regulator driver data

Parameters

struct regulator * regulator

regulator

Description

Get regulator driver private data. This call can be used in the consumer driver context when non API regulator specific functions need to be called.

void regulator_set_drvdata(struct regulator * regulator, void * data)

set regulator driver data

Parameters

struct regulator * regulator

regulator

void * data

data

int rdev_get_id(struct regulator_dev * rdev)

get regulator ID

Parameters

struct regulator_dev * rdev

regulator