drivers/power: PM: Add pm_querystate function

drivers/power/pm_changestate.c

@@ -213,4 +213,23 @@ int pm_changestate(int domain, enum pm_state_e newstate)
   return ret;
 }
 
+/****************************************************************************
+ * Name: pm_querystate
+ *
+ * Description:
+ *   This function returns the current power management state.
+ *
+ * Input Parameters:
+ *   domain - The PM domain to check
+ *
+ * Returned Value:
+ *   The current power management state.
+ *
+ ****************************************************************************/
+
+enum pm_state_e pm_querystate(int domain)
+{
+  return g_pmglobals.domain[domain].state;
+}
+
 #endif /* CONFIG_PM */

include/nuttx/power/pm.h

@@ -550,6 +550,22 @@ enum pm_state_e pm_checkstate(int domain);
 
 int pm_changestate(int domain, enum pm_state_e newstate);
 
+/****************************************************************************
+ * Name: pm_querystate
+ *
+ * Description:
+ *   This function returns the current power management state.
+ *
+ * Input Parameters:
+ *   domain - The PM domain to check
+ *
+ * Returned Value:
+ *   The current power management state.
+ *
+ ****************************************************************************/
+
+enum pm_state_e pm_querystate(int domain);
+
 #undef EXTERN
 #ifdef __cplusplus
 }
@@ -575,6 +591,7 @@ int pm_changestate(int domain, enum pm_state_e newstate);
 #  define pm_relax(domain,state)
 #  define pm_checkstate(domain)       (0)
 #  define pm_changestate(domain,state)
+#  define pm_querystate(domain)       (0)
 
 #endif /* CONFIG_PM */
 #endif /* __INCLUDE_NUTTX_POWER_PM_H */