drivers: base: opp: add devm_* for registration of notification chain

Add safe function devm_pm_opp_register_notifier() for registering
notification chain for OPP changes. The function is used in case of
deffer probe, when the device is cleaned and probe function is called
agian.

Change-Id: I188bbfaddc821489c26cb908abb05ccece831dc3
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>

diff --git a/drivers/base/power/opp/devres.c b/drivers/base/power/opp/devres.c
index 7f342dd..461523b 100644 (file)
--- a/drivers/base/power/opp/devres.c
+++ b/drivers/base/power/opp/devres.c
@@ -18,6 +18,9 @@ void dev_pm_opp_put_opp_table(struct opp_table *opp_table);
 void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev,
                              bool remove_all);
 void dev_pm_opp_remove(struct device *dev, unsigned long freq);
+int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb);
+int dev_pm_opp_unregister_notifier(struct device *dev,
+                                  struct notifier_block *nb);
 
 static void _devm_pm_remove_opp_table(struct device *dev, void *res)
 {
@@ -87,3 +90,63 @@ void devm_pm_opp_remove(struct device *dev, unsigned long freq)
        dev_pm_opp_remove(dev, freq);
 }
 EXPORT_SYMBOL_GPL(devm_pm_opp_remove);
+
+struct _opp_notifier_match {
+       struct notifier_block *nb;
+};
+
+static int _devm_opp_match_notifier(struct device *dev, void *res, void *data)
+{
+       struct _opp_notifier_match *match = res;
+       struct _opp_notifier_match *target = data;
+
+       return match->nb == target->nb;
+}
+
+static void _devm_pm_opp_notifier_destroy(struct device *dev, void *res)
+{
+       struct _opp_notifier_match *match = res;
+
+       dev_dbg(dev, "OPP_DEVRES notifier destroyed\n");
+       dev_pm_opp_unregister_notifier(dev, match->nb);
+}
+
+int devm_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb)
+{
+       int res;
+       struct _opp_notifier_match *match;
+
+       dev_dbg(dev, "OPP_DEVRES registering notifier\n");
+       match = devres_alloc(_devm_pm_opp_notifier_destroy,
+                          sizeof(struct _opp_notifier_match), GFP_KERNEL);
+       if (!match)
+               return -ENOMEM;
+
+       match->nb = nb;
+
+       res = dev_pm_opp_register_notifier(dev, nb);
+       if (res < 0) {
+               devres_free(match);
+               return res;
+       }
+
+       devres_add(dev, match);
+
+       return 0;
+}
+EXPORT_SYMBOL(devm_pm_opp_register_notifier);
+
+void devm_pm_opp_unregister_notifier(struct device *dev,
+                                    struct notifier_block *nb)
+{
+       int res;
+       struct _opp_notifier_match match;
+
+       match.nb = nb;
+
+       res = devres_release(dev, _devm_pm_opp_notifier_destroy,
+                           _devm_opp_match_notifier, &match);
+       if (res != 0)
+               WARN_ON(res);
+}
+EXPORT_SYMBOL(devm_pm_opp_unregister_notifier);