PM / Domains: Operations related to cpuidle using domain names

Make it possible to use domain names in operations connecting cpuidle
to and disconnecting it from a PM domain.  This is useful on
platforms where PM domain objects are organized in such a way that
the names of the domains are easier to use than the addresses of
those objects.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>

drivers/base/power/domain.c

@@ -1887,6 +1887,16 @@ int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state)
 	goto out;
 }
 
+/**
+ * pm_genpd_name_attach_cpuidle - Find PM domain and connect cpuidle to it.
+ * @name: Name of the domain to connect to cpuidle.
+ * @state: cpuidle state this domain can manipulate.
+ */
+int pm_genpd_name_attach_cpuidle(const char *name, int state)
+{
+	return pm_genpd_attach_cpuidle(pm_genpd_lookup_name(name), state);
+}
+
 /**
  * pm_genpd_detach_cpuidle - Remove the cpuidle connection from a PM domain.
  * @genpd: PM domain to remove the cpuidle connection from.
@@ -1925,6 +1935,15 @@ int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd)
 	return ret;
 }
 
+/**
+ * pm_genpd_name_detach_cpuidle - Find PM domain and disconnect cpuidle from it.
+ * @name: Name of the domain to disconnect cpuidle from.
+ */
+int pm_genpd_name_detach_cpuidle(const char *name)
+{
+	return pm_genpd_detach_cpuidle(pm_genpd_lookup_name(name));
+}
+
 /* Default device callbacks for generic PM domains. */
 
 /**

include/linux/pm_domain.h

@@ -156,7 +156,9 @@ extern int pm_genpd_add_callbacks(struct device *dev,
 				  struct gpd_timing_data *td);
 extern int __pm_genpd_remove_callbacks(struct device *dev, bool clear_td);
 extern int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int state);
+extern int pm_genpd_name_attach_cpuidle(const char *name, int state);
 extern int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd);
+extern int pm_genpd_name_detach_cpuidle(const char *name);
 extern void pm_genpd_init(struct generic_pm_domain *genpd,
 			  struct dev_power_governor *gov, bool is_off);
 
@@ -229,10 +231,18 @@ static inline int pm_genpd_attach_cpuidle(struct generic_pm_domain *genpd, int s
 {
 	return -ENOSYS;
 }
+static inline int pm_genpd_name_attach_cpuidle(const char *name, int state)
+{
+	return -ENOSYS;
+}
 static inline int pm_genpd_detach_cpuidle(struct generic_pm_domain *genpd)
 {
 	return -ENOSYS;
 }
+static inline int pm_genpd_name_detach_cpuidle(const char *name)
+{
+	return -ENOSYS;
+}
 static inline void pm_genpd_init(struct generic_pm_domain *genpd,
 				 struct dev_power_governor *gov, bool is_off)
 {