2 files changed, 235 insertions, 87 deletions

diff --git a/Documentation/power/regulator/consumer.txt b/Documentation/power/regulator/consumer.txt
index 5f83fd24ea84..cdebb5145c25 100644
--- a/Documentation/power/regulator/consumer.txt
+++ b/Documentation/power/regulator/consumer.txt
@@ -104,7 +104,7 @@ to set the limit to 500mA when supplying power.
 
 Consumers can control their supply current limit by calling :-
 
-int regulator_set_current_limit(regulator, min_uV, max_uV);
+int regulator_set_current_limit(regulator, min_uA, max_uA);
 
 Where min_uA and max_uA are the minimum and maximum acceptable current limit in
 microamps.
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index f49a33b704d2..55b859b3bc72 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -38,83 +38,85 @@ struct dev_pm_ops {
         ...
         int (*runtime_suspend)(struct device *dev);
         int (*runtime_resume)(struct device *dev);
-        void (*runtime_idle)(struct device *dev);
+        int (*runtime_idle)(struct device *dev);
         ...
 };
 
-The ->runtime_suspend() callback is executed by the PM core for the bus type of
-the device being suspended.  The bus type's callback is then _entirely_
-_responsible_ for handling the device as appropriate, which may, but need not
-include executing the device driver's own ->runtime_suspend() callback (from the
+The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks are
+executed by the PM core for either the bus type, or device type (if the bus
+type's callback is not defined), or device class (if the bus type's and device
+type's callbacks are not defined) of given device.  The bus type, device type
+and device class callbacks are referred to as subsystem-level callbacks in what
+follows.
+
+The subsystem-level suspend callback is _entirely_ _responsible_ for handling
+the suspend of the device as appropriate, which may, but need not include
+executing the device driver's own ->runtime_suspend() callback (from the
 PM core's point of view it is not necessary to implement a ->runtime_suspend()
-callback in a device driver as long as the bus type's ->runtime_suspend() knows
-what to do to handle the device).
+callback in a device driver as long as the subsystem-level suspend callback
+knows what to do to handle the device).
 
-  * Once the bus type's ->runtime_suspend() callback has completed successfully
+  * Once the subsystem-level suspend callback has completed successfully
     for given device, the PM core regards the device as suspended, which need
     not mean that the device has been put into a low power state.  It is
     supposed to mean, however, that the device will not process data and will
-    not communicate with the CPU(s) and RAM until its bus type's
-    ->runtime_resume() callback is executed for it.  The run-time PM status of
-    a device after successful execution of its bus type's ->runtime_suspend()
-    callback is 'suspended'.
-
-  * If the bus type's ->runtime_suspend() callback returns -EBUSY or -EAGAIN,
-    the device's run-time PM status is supposed to be 'active', which means that
-    the device _must_ be fully operational afterwards.
-
-  * If the bus type's ->runtime_suspend() callback returns an error code
-    different from -EBUSY or -EAGAIN, the PM core regards this as a fatal
-    error and will refuse to run the helper functions described in Section 4
-    for the device, until the status of it is directly set either to 'active'
-    or to 'suspended' (the PM core provides special helper functions for this
-    purpose).
-
-In particular, if the driver requires remote wakeup capability for proper
-functioning and device_may_wakeup() returns 'false' for the device, then
-->runtime_suspend() should return -EBUSY.  On the other hand, if
-device_may_wakeup() returns 'true' for the device and the device is put
-into a low power state during the execution of its bus type's
-->runtime_suspend(), it is expected that remote wake-up (i.e. hardware mechanism
-allowing the device to request a change of its power state, such as PCI PME)
-will be enabled for the device.  Generally, remote wake-up should be enabled
-for all input devices put into a low power state at run time.
-
-The ->runtime_resume() callback is executed by the PM core for the bus type of
-the device being woken up.  The bus type's callback is then _entirely_
-_responsible_ for handling the device as appropriate, which may, but need not
-include executing the device driver's own ->runtime_resume() callback (from the
-PM core's point of view it is not necessary to implement a ->runtime_resume()
-callback in a device driver as long as the bus type's ->runtime_resume() knows
-what to do to handle the device).
-
-  * Once the bus type's ->runtime_resume() callback has completed successfully,
-    the PM core regards the device as fully operational, which means that the
-    device _must_ be able to complete I/O operations as needed.  The run-time
-    PM status of the device is then 'active'.
-
-  * If the bus type's ->runtime_resume() callback returns an error code, the PM
-    core regards this as a fatal error and will refuse to run the helper
-    functions described in Section 4 for the device, until its status is
-    directly set either to 'active' or to 'suspended' (the PM core provides
-    special helper functions for this purpose).
-
-The ->runtime_idle() callback is executed by the PM core for the bus type of
-given device whenever the device appears to be idle, which is indicated to the
-PM core by two counters, the device's usage counter and the counter of 'active'
-children of the device.
+    not communicate with the CPU(s) and RAM until the subsystem-level resume
+    callback is executed for it.  The run-time PM status of a device after
+    successful execution of the subsystem-level suspend callback is 'suspended'.
+
+  * If the subsystem-level suspend callback returns -EBUSY or -EAGAIN,
+    the device's run-time PM status is 'active', which means that the device
+    _must_ be fully operational afterwards.
+
+  * If the subsystem-level suspend callback returns an error code different
+    from -EBUSY or -EAGAIN, the PM core regards this as a fatal error and will
+    refuse to run the helper functions described in Section 4 for the device,
+    until the status of it is directly set either to 'active', or to 'suspended'
+    (the PM core provides special helper functions for this purpose).
+
+In particular, if the driver requires remote wake-up capability (i.e. hardware
+mechanism allowing the device to request a change of its power state, such as
+PCI PME) for proper functioning and device_run_wake() returns 'false' for the
+device, then ->runtime_suspend() should return -EBUSY.  On the other hand, if
+device_run_wake() returns 'true' for the device and the device is put into a low
+power state during the execution of the subsystem-level suspend callback, it is
+expected that remote wake-up will be enabled for the device.  Generally, remote
+wake-up should be enabled for all input devices put into a low power state at
+run time.
+
+The subsystem-level resume callback is _entirely_ _responsible_ for handling the
+resume of the device as appropriate, which may, but need not include executing
+the device driver's own ->runtime_resume() callback (from the PM core's point of
+view it is not necessary to implement a ->runtime_resume() callback in a device
+driver as long as the subsystem-level resume callback knows what to do to handle
+the device).
+
+  * Once the subsystem-level resume callback has completed successfully, the PM
+    core regards the device as fully operational, which means that the device
+    _must_ be able to complete I/O operations as needed.  The run-time PM status
+    of the device is then 'active'.
+
+  * If the subsystem-level resume callback returns an error code, the PM core
+    regards this as a fatal error and will refuse to run the helper functions
+    described in Section 4 for the device, until its status is directly set
+    either to 'active' or to 'suspended' (the PM core provides special helper
+    functions for this purpose).
+
+The subsystem-level idle callback is executed by the PM core whenever the device
+appears to be idle, which is indicated to the PM core by two counters, the
+device's usage counter and the counter of 'active' children of the device.
 
   * If any of these counters is decreased using a helper function provided by
     the PM core and it turns out to be equal to zero, the other counter is
     checked.  If that counter also is equal to zero, the PM core executes the
-    device bus type's ->runtime_idle() callback (with the device as an
-    argument).
+    subsystem-level idle callback with the device as an argument.
 
-The action performed by a bus type's ->runtime_idle() callback is totally
-dependent on the bus type in question, but the expected and recommended action
-is to check if the device can be suspended (i.e. if all of the conditions
-necessary for suspending the device are satisfied) and to queue up a suspend
-request for the device in that case.
+The action performed by a subsystem-level idle callback is totally dependent on
+the subsystem in question, but the expected and recommended action is to check
+if the device can be suspended (i.e. if all of the conditions necessary for
+suspending the device are satisfied) and to queue up a suspend request for the
+device in that case.  The value returned by this callback is ignored by the PM
+core.
 
 The helper functions provided by the PM core, described in Section 4, guarantee
 that the following constraints are met with respect to the bus type's run-time
@@ -214,11 +216,20 @@ defined in include/linux/pm.h:
       being executed for that device and it is not practical to wait for the
       suspend to complete; means "start a resume as soon as you've suspended"
 
+  unsigned int run_wake;
+    - set if the device is capable of generating run-time wake-up events
+
   enum rpm_status runtime_status;
     - the run-time PM status of the device; this field's initial value is
       RPM_SUSPENDED, which means that each device is initially regarded by the
       PM core as 'suspended', regardless of its real hardware status
 
+  unsigned int runtime_auto;
+    - if set, indicates that the user space has allowed the device driver to
+      power manage the device at run time via the /sys/devices/.../power/control
+      interface; it may only be modified with the help of the pm_runtime_allow()
+      and pm_runtime_forbid() helper functions
+
 All of the above fields are members of the 'power' member of 'struct device'.
 
 4. Run-time PM Device Helper Functions
@@ -234,41 +245,41 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       removing the device from device hierarchy
 
   int pm_runtime_idle(struct device *dev);
-    - execute ->runtime_idle() for the device's bus type; returns 0 on success
-      or error code on failure, where -EINPROGRESS means that ->runtime_idle()
-      is already being executed
+    - execute the subsystem-level idle callback for the device; returns 0 on
+      success or error code on failure, where -EINPROGRESS means that
+      ->runtime_idle() is already being executed
 
   int pm_runtime_suspend(struct device *dev);
-    - execute ->runtime_suspend() for the device's bus type; returns 0 on
+    - execute the subsystem-level suspend callback for the device; returns 0 on
       success, 1 if the device's run-time PM status was already 'suspended', or
       error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt
       to suspend the device again in future
 
   int pm_runtime_resume(struct device *dev);
-    - execute ->runtime_resume() for the device's bus type; returns 0 on
+    - execute the subsystem-level resume callback for the device; returns 0 on
       success, 1 if the device's run-time PM status was already 'active' or
       error code on failure, where -EAGAIN means it may be safe to attempt to
       resume the device again in future, but 'power.runtime_error' should be
       checked additionally
 
   int pm_request_idle(struct device *dev);
-    - submit a request to execute ->runtime_idle() for the device's bus type
-      (the request is represented by a work item in pm_wq); returns 0 on success
-      or error code if the request has not been queued up
+    - submit a request to execute the subsystem-level idle callback for the
+      device (the request is represented by a work item in pm_wq); returns 0 on
+      success or error code if the request has not been queued up
 
   int pm_schedule_suspend(struct device *dev, unsigned int delay);
-    - schedule the execution of ->runtime_suspend() for the device's bus type
-      in future, where 'delay' is the time to wait before queuing up a suspend
-      work item in pm_wq, in milliseconds (if 'delay' is zero, the work item is
-      queued up immediately); returns 0 on success, 1 if the device's PM
+    - schedule the execution of the subsystem-level suspend callback for the
+      device in future, where 'delay' is the time to wait before queuing up a
+      suspend work item in pm_wq, in milliseconds (if 'delay' is zero, the work
+      item is queued up immediately); returns 0 on success, 1 if the device's PM
       run-time status was already 'suspended', or error code if the request
       hasn't been scheduled (or queued up if 'delay' is 0); if the execution of
       ->runtime_suspend() is already scheduled and not yet expired, the new
       value of 'delay' will be used as the time to wait
 
   int pm_request_resume(struct device *dev);
-    - submit a request to execute ->runtime_resume() for the device's bus type
-      (the request is represented by a work item in pm_wq); returns 0 on
+    - submit a request to execute the subsystem-level resume callback for the
+      device (the request is represented by a work item in pm_wq); returns 0 on
       success, 1 if the device's run-time PM status was already 'active', or
       error code if the request hasn't been queued up
 
@@ -299,12 +310,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       run-time PM callbacks described in Section 2
 
   int pm_runtime_disable(struct device *dev);
-    - prevent the run-time PM helper functions from running the device bus
-      type's run-time PM callbacks, make sure that all of the pending run-time
-      PM operations on the device are either completed or canceled; returns
-      1 if there was a resume request pending and it was necessary to execute
-      ->runtime_resume() for the device's bus type to satisfy that request,
-      otherwise 0 is returned
+    - prevent the run-time PM helper functions from running subsystem-level
+      run-time PM callbacks for the device, make sure that all of the pending
+      run-time PM operations on the device are either completed or canceled;
+      returns 1 if there was a resume request pending and it was necessary to
+      execute the subsystem-level resume callback for the device to satisfy that
+      request, otherwise 0 is returned
 
   void pm_suspend_ignore_children(struct device *dev, bool enable);
     - set/unset the power.ignore_children flag of the device
@@ -324,6 +335,20 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       'power.runtime_error' is set or 'power.disable_depth' is greater than
       zero)
 
+  bool pm_runtime_suspended(struct device *dev);
+    - return true if the device's runtime PM status is 'suspended', or false
+      otherwise
+
+  void pm_runtime_allow(struct device *dev);
+    - set the power.runtime_auto flag for the device and decrease its usage
+      counter (used by the /sys/devices/.../power/control interface to
+      effectively allow the device to be power managed at run time)
+
+  void pm_runtime_forbid(struct device *dev);
+    - unset the power.runtime_auto flag for the device and increase its usage
+      counter (used by the /sys/devices/.../power/control interface to
+      effectively prevent the device from being power managed at run time)
+
 It is safe to execute the following helper functions from interrupt context:
 
 pm_request_idle()
@@ -374,5 +399,128 @@ pm_runtime_suspend() or pm_runtime_idle() or their asynchronous counterparts,
 they will fail returning -EAGAIN, because the device's usage counter is
 incremented by the core before executing ->probe() and ->remove().  Still, it
 may be desirable to suspend the device as soon as ->probe() or ->remove() has
-finished, so the PM core uses pm_runtime_idle_sync() to invoke the device bus
-type's ->runtime_idle() callback at that time.
+finished, so the PM core uses pm_runtime_idle_sync() to invoke the
+subsystem-level idle callback for the device at that time.
+
+The user space can effectively disallow the driver of the device to power manage
+it at run time by changing the value of its /sys/devices/.../power/control
+attribute to "on", which causes pm_runtime_forbid() to be called.  In principle,
+this mechanism may also be used by the driver to effectively turn off the
+run-time power management of the device until the user space turns it on.
+Namely, during the initialization the driver can make sure that the run-time PM
+status of the device is 'active' and call pm_runtime_forbid().  It should be
+noted, however, that if the user space has already intentionally changed the
+value of /sys/devices/.../power/control to "auto" to allow the driver to power
+manage the device at run time, the driver may confuse it by using
+pm_runtime_forbid() this way.
+
+6. Run-time PM and System Sleep
+
+Run-time PM and system sleep (i.e., system suspend and hibernation, also known
+as suspend-to-RAM and suspend-to-disk) interact with each other in a couple of
+ways.  If a device is active when a system sleep starts, everything is
+straightforward.  But what should happen if the device is already suspended?
+
+The device may have different wake-up settings for run-time PM and system sleep.
+For example, remote wake-up may be enabled for run-time suspend but disallowed
+for system sleep (device_may_wakeup(dev) returns 'false').  When this happens,
+the subsystem-level system suspend callback is responsible for changing the
+device's wake-up setting (it may leave that to the device driver's system
+suspend routine).  It may be necessary to resume the device and suspend it again
+in order to do so.  The same is true if the driver uses different power levels
+or other settings for run-time suspend and system sleep.
+
+During system resume, devices generally should be brought back to full power,
+even if they were suspended before the system sleep began.  There are several
+reasons for this, including:
+
+  * The device might need to switch power levels, wake-up settings, etc.
+
+  * Remote wake-up events might have been lost by the firmware.
+
+  * The device's children may need the device to be at full power in order
+    to resume themselves.
+
+  * The driver's idea of the device state may not agree with the device's
+    physical state.  This can happen during resume from hibernation.
+
+  * The device might need to be reset.
+
+  * Even though the device was suspended, if its usage counter was > 0 then most
+    likely it would need a run-time resume in the near future anyway.
+
+  * Always going back to full power is simplest.
+
+If the device was suspended before the sleep began, then its run-time PM status
+will have to be updated to reflect the actual post-system sleep status.  The way
+to do this is:
+
+        pm_runtime_disable(dev);
+        pm_runtime_set_active(dev);
+        pm_runtime_enable(dev);
+
+The PM core always increments the run-time usage counter before calling the
+->prepare() callback and decrements it after calling the ->complete() callback.
+Hence disabling run-time PM temporarily like this will not cause any run-time
+suspend callbacks to be lost.
+
+7. Generic subsystem callbacks
+
+Subsystems may wish to conserve code space by using the set of generic power
+management callbacks provided by the PM core, defined in
+driver/base/power/generic_ops.c:
+
+  int pm_generic_runtime_idle(struct device *dev);
+    - invoke the ->runtime_idle() callback provided by the driver of this
+      device, if defined, and call pm_runtime_suspend() for this device if the
+      return value is 0 or the callback is not defined
+
+  int pm_generic_runtime_suspend(struct device *dev);
+    - invoke the ->runtime_suspend() callback provided by the driver of this
+      device and return its result, or return -EINVAL if not defined
+
+  int pm_generic_runtime_resume(struct device *dev);
+    - invoke the ->runtime_resume() callback provided by the driver of this
+      device and return its result, or return -EINVAL if not defined
+
+  int pm_generic_suspend(struct device *dev);
+    - if the device has not been suspended at run time, invoke the ->suspend()
+      callback provided by its driver and return its result, or return 0 if not
+      defined
+
+  int pm_generic_resume(struct device *dev);
+    - invoke the ->resume() callback provided by the driver of this device and,
+      if successful, change the device's runtime PM status to 'active'
+
+  int pm_generic_freeze(struct device *dev);
+    - if the device has not been suspended at run time, invoke the ->freeze()
+      callback provided by its driver and return its result, or return 0 if not
+      defined
+
+  int pm_generic_thaw(struct device *dev);
+    - if the device has not been suspended at run time, invoke the ->thaw()
+      callback provided by its driver and return its result, or return 0 if not
+      defined
+
+  int pm_generic_poweroff(struct device *dev);
+    - if the device has not been suspended at run time, invoke the ->poweroff()
+      callback provided by its driver and return its result, or return 0 if not
+      defined
+
+  int pm_generic_restore(struct device *dev);
+    - invoke the ->restore() callback provided by the driver of this device and,
+      if successful, change the device's runtime PM status to 'active'
+
+These functions can be assigned to the ->runtime_idle(), ->runtime_suspend(),
+->runtime_resume(), ->suspend(), ->resume(), ->freeze(), ->thaw(), ->poweroff(),
+or ->restore() callback pointers in the subsystem-level dev_pm_ops structures.
+
+If a subsystem wishes to use all of them at the same time, it can simply assign
+the GENERIC_SUBSYS_PM_OPS macro, defined in include/linux/pm.h, to its
+dev_pm_ops structure pointer.
+
+Device drivers that wish to use the same function as a system suspend, freeze,
+poweroff and run-time suspend callback, and similarly for system resume, thaw,
+restore, and run-time resume, can achieve this with the help of the
+UNIVERSAL_DEV_PM_OPS macro defined in include/linux/pm.h (possibly setting its
+last argument to NULL).