pm: Add a new function to query the next power state

Add a function that can be used by device drivers to know
what will be next power state used by the SoC.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>

include/pm/pm.h

@@ -173,6 +173,16 @@ bool pm_constraint_get(enum pm_state state);
  */
 void pm_power_state_set(struct pm_state_info info);
 
+/**
+ * @brief Gets the next power state that will be used.
+ *
+ * This function returns the next power state that will be used by the
+ * SoC.
+ *
+ * @return next pm_state_info that will be used
+ */
+const struct pm_state_info pm_power_state_next_get(void);
+
 /**
  * @brief Do any SoC or architecture specific post ops after sleep state exits.
  *
@@ -198,6 +208,8 @@ void pm_power_state_exit_post_ops(struct pm_state_info info);
 
 #define pm_power_state_set(info)
 #define pm_power_state_exit_post_ops(info)
+#define pm_power_state_next_get() \
+	((struct pm_state_info){PM_STATE_ACTIVE, 0, 0})
 
 #endif /* CONFIG_PM */
 

subsys/pm/power.c

@@ -323,3 +323,8 @@ int pm_notifier_unregister(struct pm_notifier *notifier)
 
 	return ret;
 }
+
+const struct pm_state_info pm_power_state_next_get(void)
+{
+	return z_power_state;
+}