PM / Domains: Convert to dev_to_genpd_safe() in genpd_syscore_switch()

The intent with walking the gpd_list via calling genpd_present() from
genpd_syscore_switch(), is to make sure the dev->pm_domain pointer belongs
to a registered genpd. However, as a genpd can't be removed if there is a
device attached to it, let's convert to use the quicker dev_to_genpd_safe()
instead.

Due to the above change, this allows us to clean up genpd_present() and
move it inside CONFIG_PM_GENERIC_DOMAINS_OF, so let's do that as well.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -929,24 +929,6 @@ static int __init genpd_power_off_unused(void)
 }
 late_initcall(genpd_power_off_unused);
 
-#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM_GENERIC_DOMAINS_OF)
-
-static bool genpd_present(const struct generic_pm_domain *genpd)
-{
-	const struct generic_pm_domain *gpd;
-
-	if (IS_ERR_OR_NULL(genpd))
-		return false;
-
-	list_for_each_entry(gpd, &gpd_list, gpd_list_node)
-		if (gpd == genpd)
-			return true;
-
-	return false;
-}
-
-#endif
-
 #ifdef CONFIG_PM_SLEEP
 
 /**
@@ -1361,8 +1343,8 @@ static void genpd_syscore_switch(struct device *dev, bool suspend)
 {
 	struct generic_pm_domain *genpd;
 
-	genpd = dev_to_genpd(dev);
-	if (!genpd_present(genpd))
+	genpd = dev_to_genpd_safe(dev);
+	if (!genpd)
 		return;
 
 	if (suspend) {
@@ -2028,6 +2010,16 @@ static int genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
 	return 0;
 }
 
+static bool genpd_present(const struct generic_pm_domain *genpd)
+{
+	const struct generic_pm_domain *gpd;
+
+	list_for_each_entry(gpd, &gpd_list, gpd_list_node)
+		if (gpd == genpd)
+			return true;
+	return false;
+}
+
 /**
  * of_genpd_add_provider_simple() - Register a simple PM domain provider
  * @np: Device node pointer associated with the PM domain provider.