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Work in progress! |
Allow systems Platforms have a set of voltage and current regulators to dynamically control regulator power output in order to save power and prolong battery life.
Voltage Regulators take an input supply and produce a target voltage.
Which devices need Regulators?
Audio
WiFi
BT
HDMI etc.
Why do we need to drive the regulator?
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Power saving
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Hardware Interfacing
Which Devices need a dynamic regulator?
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SD Card
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Requires two supplies.
1.8v and 3.3v
But no need to change dynamically voltage.
Types of Regulator
PMIC
GPIO Regulator
SoC built-in regulator
or to match certain system operating points. E.g: LCD backlight driver would need to change the current limit to vary the backlight brightness.
Arm client platforms with DT make use of the regulator binding to describe regulator devices and consumer devices for regulators. Device drivers use the regulator framework to dynamically enable/disable voltage rails or configure the voltage or current limits.
ACPI bindings for Regulator
ACPI doesn’t have any bindings available for the regulator specifically and the regulator enable/disable etc. are typically handled by the ACPI device power methods.
Looking at a diverse set of devices like low-speed/high-speed IO, sound cards, video, backlight, etc. for multiple Arm platforms, there doesn’t seem to any need for voltage regular binding beyond what is required for power saving which is already handled by the device power methods.