The patch "PM / Runtime: Implement autosuspend support" introduces
"autosuspend" facility for runtime PM, but misses helper function
of pm_request_autosuspend, so add it.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

This patch (as1427) implements the "autosuspend" facility for runtime
PM.  A few new fields are added to the dev_pm_info structure and
several new PM helper functions are defined, for telling the PM core
whether or not a device uses autosuspend, for setting the autosuspend
delay, and for marking periods of device activity.

Drivers that do not want to use autosuspend can continue using the
same helper functions as before; their behavior will not change.  In
addition, drivers supporting autosuspend can also call the old helper
functions to get the old behavior.

The details are all explained in Documentation/power/runtime_pm.txt
and Documentation/ABI/testing/sysfs-devices-power.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Some devices, such as USB interfaces, cannot be power-managed
independently of their parents, i.e., they cannot be put in low power
while the parent remains at full power.  This patch (as1425) creates a
new "no_callbacks" flag, which tells the PM core not to invoke the
runtime-PM callback routines for the such devices but instead to
assume that the callbacks always succeed.  In addition, the
non-debugging runtime-PM sysfs attributes for the devices are removed,
since they are pretty much meaningless.

The advantage of this scheme comes not so much from avoiding the
callbacks themselves, but rather from the fact that without the need
for a process context in which to run the callbacks, more work can be
done in interrupt context.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

This patch (as1424) combines the various public entry points for the
runtime PM routines into three simple functions: one for idle, one for
suspend, and one for resume.  A new bitflag specifies whether or not
to increment or decrement the usage_count field.

The new entry points are named __pm_runtime_idle,
__pm_runtime_suspend, and __pm_runtime_resume, to reflect that they
are trampolines.  Simultaneously, the corresponding internal routines
are renamed to rpm_idle, rpm_suspend, and rpm_resume.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

The "from_wq" argument in __pm_runtime_suspend() and
__pm_runtime_resume() supposedly indicates whether or not the function
was called by the PM workqueue thread, but in fact it isn't always
used this way.  It really indicates whether or not the function should
return early if the requested operation is already in progress.

Along with this badly-named boolean argument, later patches in this
series will add several other boolean arguments to these functions and
others.  Therefore this patch (as1422) begins the conversion process
by replacing from_wq with a bitflag argument.  The same bitflags are
also used in __pm_runtime_get() and __pm_runtime_put(), where they
indicate whether or not the operation should be asynchronous.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

There are three issues with the i2c bus type's power management
callbacks at the moment.  First, they don't include any hibernate
callbacks, although they should at least include the .restore()
callback (there's no guarantee that the driver will be present in
memory before loading the image kernel and we must restore the
pre-hibernation state of the device).  Second, the "legacy"
callbacks are not going to be invoked by the PM core since the bus
type's pm object is not NULL.  Finally, the system sleep PM
(ie. suspend/resume) callbacks don't check if the device has been
already suspended at run time, in which case they should skip
suspending it.  Also, it looks like the i2c bus type can use the
generic subsystem-level runtime PM callbacks.

For these reasons, rework the system sleep PM callbacks provided by
the i2c bus type to handle hibernation correctly and to invoke the
"legacy" callbacks for drivers that provide them.  In addition to
that make the i2c bus type use the generic subsystem-level runtime
PM callbacks.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: NJean Delvare <khali@linux-fr.org>

There are subsystems whose power management callbacks only need to
invoke the callbacks provided by device drivers.  Still, their system
sleep PM callbacks should play well with the runtime PM callbacks,
so that devices suspended at run time can be left in that state for
a system sleep transition.

Provide a set of generic PM callbacks for such subsystems and
define convenience macros for populating dev_pm_ops structures.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Add new device sysfs attribute, power/control, allowing the user
space to block the run-time power management of the devices.  If this
attribute is set to "on", the driver of the device won't be able to power
manage it at run time (without breaking the rules) and the device will
always be in the full power state (except when the entire system goes
into a sleep state).
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>

Apparently, there are devices that can wake up the system from sleep
states and yet are incapable of generating wake-up events at run
time.  Thus, introduce a flag indicating if given device is capable
of generating run-time wake-up events.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

Introduce a core framework for run-time power management of I/O
devices.  Add device run-time PM fields to 'struct dev_pm_info'
and device run-time PM callbacks to 'struct dev_pm_ops'.  Introduce
a run-time PM workqueue and define some device run-time PM helper
functions at the core level.  Document all these things.

Special thanks to Alan Stern for his help with the design and
multiple detailed reviews of the pereceding versions of this patch
and to Magnus Damm for testing feedback.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NMagnus Damm <damm@igel.co.jp>