PM / suspend: Export pm_suspend_target_state

Have the core suspend/resume framework store the system-wide suspend
state (suspend_state_t) we are about to enter, and expose it to drivers
via pm_suspend_target_state in order to retrieve that. The state is
assigned in suspend_devices_and_enter().

This is useful for platform specific drivers that may need to take a
slightly different suspend/resume path based on the system's
suspend/resume state being entered.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/suspend.h

@@ -427,6 +427,7 @@ extern int unregister_pm_notifier(struct notifier_block *nb);
 /* drivers/base/power/wakeup.c */
 extern bool events_check_enabled;
 extern unsigned int pm_wakeup_irq;
+extern suspend_state_t pm_suspend_target_state;
 
 extern bool pm_wakeup_pending(void);
 extern void pm_system_wakeup(void);

kernel/power/suspend.c

@@ -47,6 +47,8 @@ const char *mem_sleep_states[PM_SUSPEND_MAX];
 
 suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE;
 static suspend_state_t mem_sleep_default = PM_SUSPEND_MEM;
+suspend_state_t pm_suspend_target_state;
+EXPORT_SYMBOL_GPL(pm_suspend_target_state);
 
 unsigned int pm_suspend_global_flags;
 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
@@ -456,6 +458,8 @@ int suspend_devices_and_enter(suspend_state_t state)
 	if (!sleep_state_supported(state))
 		return -ENOSYS;
 
+	pm_suspend_target_state = state;
+
 	error = platform_suspend_begin(state);
 	if (error)
 		goto Close;
@@ -485,6 +489,7 @@ int suspend_devices_and_enter(suspend_state_t state)
 
  Close:
 	platform_resume_end(state);
+	pm_suspend_target_state = PM_SUSPEND_ON;
 	return error;
 
  Recover_platform: