This adds documentation describing the consumer device interface.
Signed-off-by: Liam Girdwood <[email protected]>
---
Documentation/power/regulator/consumer.txt | 182 ++++++++++++++++++++++++++++
1 files changed, 182 insertions(+), 0 deletions(-)
create mode 100644 Documentation/power/regulator/consumer.txt
diff --git a/Documentation/power/regulator/consumer.txt b/Documentation/power/regulator/consumer.txt
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+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 initialisation 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
+determind 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.
--
1.5.4.3
Liam Girdwood wrote:
> This adds documentation describing the consumer device interface.
>
> Signed-off-by: Liam Girdwood <[email protected]>
> ---
> Documentation/power/regulator/consumer.txt | 182 ++++++++++++++++++++++++++++
> 1 files changed, 182 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/power/regulator/consumer.txt
>
> diff --git a/Documentation/power/regulator/consumer.txt b/Documentation/power/regulator/consumer.txt
> new file mode 100644
> index 0000000..9ea688d
> --- /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 initialisation code.
initialization
^
> +
> +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
> +determind the regulator physical output voltage.
determine
^
> +
> +
> +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.
On Fri, Jul 11, 2008 at 06:10:13PM +0300, Paulius Zaleckas wrote:
> Liam Girdwood wrote:
> >+previously enabled by bootloader or kernel board initialisation code.
> initialization
> ^
Not in the UK :)
--
"You grabbed my hand and we fell into it, like a daydream - or a fever."
On Fri, Jul 11, 2008 at 08:18:25PM +0100, Mark Brown wrote:
> On Fri, Jul 11, 2008 at 06:10:13PM +0300, Paulius Zaleckas wrote:
> > Liam Girdwood wrote:
>
> > >+previously enabled by bootloader or kernel board initialisation code.
>
> > initialization
> > ^
>
> Not in the UK :)
Actually, wrong. "Initialize" is correct spelling in the UK too - I've
checked several UK dictionaries printed in the 1960s, 1970s and 1980s
sourced from different printers, and they all agree on that.
At the same time I checked other words which I thought ended in -ise.
The dictionaries all said -ize and didn't list the -ise version.
Therefore, I suspect -ise came into use in the late 1980s in the UK.
Given my research, I'm intending to use the -ize version myself from
now on, to support the English ideals. 8)
On Thu, Jul 17, 2008 at 07:39:31PM +0100, Russell King - ARM Linux wrote:
> On Fri, Jul 11, 2008 at 08:18:25PM +0100, Mark Brown wrote:
> > On Fri, Jul 11, 2008 at 06:10:13PM +0300, Paulius Zaleckas wrote:
> > > Liam Girdwood wrote:
> > > initialization
> > Not in the UK :)
...
> At the same time I checked other words which I thought ended in -ise.
> The dictionaries all said -ize and didn't list the -ise version.
> Therefore, I suspect -ise came into use in the late 1980s in the UK.
> Given my research, I'm intending to use the -ize version myself from
> now on, to support the English ideals. 8)
Heh. This fits the general pattern where American and English spellings
diverge - usually it's the English spelling which changed rather than
the American one. It's not normally so recent, though.
--
"You grabbed my hand and we fell into it, like a daydream - or a fever."
On Thu, 2008-07-17 at 19:39 +0100, Russell King - ARM Linux wrote:
> On Fri, Jul 11, 2008 at 08:18:25PM +0100, Mark Brown wrote:
> > On Fri, Jul 11, 2008 at 06:10:13PM +0300, Paulius Zaleckas wrote:
> > > Liam Girdwood wrote:
> >
> > > >+previously enabled by bootloader or kernel board initialisation code.
> >
> > > initialization
> > > ^
> >
> > Not in the UK :)
>
> Actually, wrong. "Initialize" is correct spelling in the UK too - I've
> checked several UK dictionaries printed in the 1960s, 1970s and 1980s
> sourced from different printers, and they all agree on that.
>
> At the same time I checked other words which I thought ended in -ise.
> The dictionaries all said -ize and didn't list the -ise version.
>
> Therefore, I suspect -ise came into use in the late 1980s in the UK.
>
> Given my research, I'm intending to use the -ize version myself from
> now on, to support the English ideals. 8)
ok, I concede. -ize it is ;)
Liam