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 abd81ffaba3..40f3f45702b 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;