• Ulf Hansson's avatar
    PM / wakeup: Add device_set_wakeup_path() helper to control wakeup path · cf04ce78
    Ulf Hansson authored
    During system suspend, a driver may find that the wakeup setting is
    enabled for its device and therefore configures it to deliver system
    wakeup signals.
    
    Additionally, sometimes the driver and its device, relies on some
    further consumed resource, like an irqchip or a phy for example, to
    stay powered on, as to be able to deliver system wakeup signals.
    
    In general the driver deals with this, via raising an "enable count"
    of the consumed resource or via a subsystem specific API, like
    irq_set_irq_wake() or enable|disable_irq_wake() for an irqchip.
    However, this may not be sufficient in cases when the resource's
    device may be attached to a PM domain (genpd for example) or is
    handled by a non-trivial middle layer (PCI for example).
    
    To address cases like these, the existing ->dev.power.wakeup_path
    status flag is there to help.  As a matter of fact, genpd already
    monitors the flag during system suspend and acts accordingly.
    
    However, so far it has not been clear, if anybody else but the PM
    core is allowed to set the ->dev.power.wakeup_path status flag,
    which is required to make this work.  For this reason, introduce
    a new helper function, device_set_wakeup_path() for that.
    
    Typically, a driver that manages a resource needed in the wakeup path
    should call device_set_wakeup_path() from its ->suspend() or
    ->suspend_late() callback.
    Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    cf04ce78
pm_wakeup.h 6.78 KB