PM / Runtime: Implement autosuspend support

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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index abd81ffaba3c..40f3f45702ba 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -444,6 +444,9 @@ enum rpm_status {
  *
  * RPM_REQ_SUSPEND      Run the device bus type's ->runtime_suspend() callback
  *
+ * RPM_REQ_AUTOSUSPEND  Same as RPM_REQ_SUSPEND, but not until the device has
+ *                      been inactive for as long as power.autosuspend_delay
+ *
  * RPM_REQ_RESUME       Run the device bus type's ->runtime_resume() callback
  */
 
@@ -451,6 +454,7 @@ enum rpm_request {
         RPM_REQ_NONE = 0,
         RPM_REQ_IDLE,
         RPM_REQ_SUSPEND,
+        RPM_REQ_AUTOSUSPEND,
         RPM_REQ_RESUME,
 };
 
@@ -482,9 +486,13 @@ struct dev_pm_info {
         unsigned int            run_wake:1;
         unsigned int            runtime_auto:1;
         unsigned int            no_callbacks:1;
+        unsigned int            use_autosuspend:1;
+        unsigned int            timer_autosuspends:1;
         enum rpm_request        request;
         enum rpm_status         runtime_status;
         int                     runtime_error;
+        int                     autosuspend_delay;
+        unsigned long           last_busy;
         unsigned long           active_jiffies;
         unsigned long           suspended_jiffies;
         unsigned long           accounting_timestamp;