• Mark Brown's avatar
    ACPI / init: Flag use of ACPI and ACPI idioms for power supplies to regulator API · 3111943e
    Mark Brown authored
    commit 49a12877 upstream.
    
    There is currently no facility in ACPI to express the hookup of voltage
    regulators, the expectation is that the regulators that exist in the
    system will be handled transparently by firmware if they need software
    control at all. This means that if for some reason the regulator API is
    enabled on such a system it should assume that any supplies that devices
    need are provided by the system at all relevant times without any software
    intervention.
    
    Tell the regulator core to make this assumption by calling
    regulator_has_full_constraints(). Do this as soon as we know we are using
    ACPI so that the information is available to the regulator core as early
    as possible. This will cause the regulator core to pretend that there is
    an always on regulator supplying any supply that is requested but that has
    not otherwise been mapped which is the behaviour expected on a system with
    ACPI.
    
    Should the ability to specify regulators be added in future revisions of
    ACPI then once we have support for ACPI mappings in the kernel the same
    assumptions will apply. It is also likely that systems will default to a
    mode of operation which does not require any interpretation of these
    mappings in order to be compatible with existing operating system releases
    so it should remain safe to make these assumptions even if the mappings
    exist but are not supported by the kernel.
    Signed-off-by: default avatarMark Brown <broonie@linaro.org>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    3111943e
bus.c 25.7 KB