PM / Domains: Convert pm_genpd_init() to return an error code

The are already cases when pm_genpd_init() can fail. Currently we hide the
failures instead of propagating an error code, which is a better method.

Moreover, to prepare for future changes like moving away from using a
fixed array-size of the struct genpd_power_state, to instead dynamically
allocate data for it, the pm_genpd_init() API needs to be able to return
an error code, as allocation can fail.

Current users of the pm_genpd_init() is thus requested to start dealing
with error codes. In the transition phase, users will have to live with
only error messages being printed to log.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 12 insertions, 7 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 9193aacf7b1b..a1f2aff33997 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1258,12 +1258,14 @@ EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
  * @genpd: PM domain object to initialize.
  * @gov: PM domain governor to associate with the domain (may be NULL).
  * @is_off: Initial value of the domain's power_is_off field.
+ *
+ * Returns 0 on successful initialization, else a negative error code.
  */
-void pm_genpd_init(struct generic_pm_domain *genpd,
-                   struct dev_power_governor *gov, bool is_off)
+int pm_genpd_init(struct generic_pm_domain *genpd,
+                  struct dev_power_governor *gov, bool is_off)
 {
         if (IS_ERR_OR_NULL(genpd))
-                return;
+                return -EINVAL;
 
         INIT_LIST_HEAD(&genpd->master_links);
         INIT_LIST_HEAD(&genpd->slave_links);
@@ -1321,6 +1323,8 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
         mutex_lock(&gpd_list_lock);
         list_add(&genpd->gpd_list_node, &gpd_list);
         mutex_unlock(&gpd_list_lock);
+
+        return 0;
 }
 EXPORT_SYMBOL_GPL(pm_genpd_init);
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index dd5b0447d572..31fec858088c 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -127,8 +127,8 @@ extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
                                   struct generic_pm_domain *new_subdomain);
 extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
                                      struct generic_pm_domain *target);
-extern void pm_genpd_init(struct generic_pm_domain *genpd,
-                          struct dev_power_governor *gov, bool is_off);
+extern int pm_genpd_init(struct generic_pm_domain *genpd,
+                         struct dev_power_governor *gov, bool is_off);
 
 extern struct dev_power_governor simple_qos_governor;
 extern struct dev_power_governor pm_domain_always_on_gov;
@@ -163,9 +163,10 @@ static inline int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 {
         return -ENOSYS;
 }
-static inline void pm_genpd_init(struct generic_pm_domain *genpd,
-                                 struct dev_power_governor *gov, bool is_off)
+static inline int pm_genpd_init(struct generic_pm_domain *genpd,
+                                struct dev_power_governor *gov, bool is_off)
 {
+        return -ENOSYS;
 }
 #endif