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    Subject[UPDATED v2][PATCH 0/6] regulator: voltage and current regulator framework
    Version 2 with thanks to Sam Ravnborg, Mariusz Kozlowski, David Brownell
    and Laura Lawrence for their comments.

    This patch series provides a generic framework to allow device drivers
    to control voltage and current regulators on SoC based devices (e.g.
    phones, gps, media players).

    The intention is to allow systems to dynamically control regulator
    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 output is controllable).

    The framework is designed around SoC based devices but may also be
    relevant to non SoC devices. It's also been designed against two Power
    Management ICs (PMICs) currently on the market - namely the Freescale
    MC13783 and the Wolfson WM8350. However it is quite generic and should
    apply to all PMICs.

    The framework provides several interfaces :-

    1. Client or Consumer driver API.

    This uses a similar API to the kernel clock interface in that client
    or consumer drivers can get and put a regulator (like they can with
    clocks atm) and get/set voltage, current, mode, enable and disable. This
    should allow clients complete control over their supply voltage and
    current. This API also compiles out if not in use so drivers can be
    reused in systems with no PMIC power control.

    2. Regulator driver API.

    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.

    3. Platform API.

    This API is for platform/device 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
    over voltage 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).

    4. Userspace.

    The framework also exports a lot of useful voltage/current data to
    userspace via sysfs. This could be used to monitor device and regulator
    power and status.

    Fwiw, there is a project page here :-

    and code in our public git tree that currently shows this API
    in use:-;a=shortlog;h=imx31

    All the relevant files are under include/linux/regulator and
    drivers/regulator. There are client drivers here :-;a=blob;f=arch/arm/mach-mx3/cpufreq.c;h=77f03d85fef6b29b0ca2e820d38d9ebb068e7bf7;hb=imx31;a=blob;f=drivers/leds/leds-wm8350.c;h=a81bbf9154b4de13c029aee0613294562a03f506;hb=imx31;a=blob;f=drivers/video/backlight/wm8350_bl.c;h=3eafb83683b7f242ec78ff620431307c25e23202;hb=imx31;a=blob;f=sound/soc/imx/imx32ads-wm8350.c;h=aae347ac556203fbdb64d71f4dc0be7df250767a;hb=imx31

    Patch follows.


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