drivers: phy: Handle gracefully NULL pointers

For some controllers PHYs can be optional. Handling NULL pointers without
crashing nor failing, makes it easy to handle optional PHYs.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/drivers/phy/phy-uclass.c b/drivers/phy/phy-uclass.c
index a0ac30a..e201a90 100644
--- a/drivers/phy/phy-uclass.c
+++ b/drivers/phy/phy-uclass.c
@@ -108,35 +108,55 @@
 
 int generic_phy_init(struct phy *phy)
 {
-	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+	struct phy_ops const *ops;
+
+	if (!phy)
+		return 0;
+	ops = phy_dev_ops(phy->dev);
 
 	return ops->init ? ops->init(phy) : 0;
 }
 
 int generic_phy_reset(struct phy *phy)
 {
-	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+	struct phy_ops const *ops;
+
+	if (!phy)
+		return 0;
+	ops = phy_dev_ops(phy->dev);
 
 	return ops->reset ? ops->reset(phy) : 0;
 }
 
 int generic_phy_exit(struct phy *phy)
 {
-	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+	struct phy_ops const *ops;
+
+	if (!phy)
+		return 0;
+	ops = phy_dev_ops(phy->dev);
 
 	return ops->exit ? ops->exit(phy) : 0;
 }
 
 int generic_phy_power_on(struct phy *phy)
 {
-	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+	struct phy_ops const *ops;
+
+	if (!phy)
+		return 0;
+	ops = phy_dev_ops(phy->dev);
 
 	return ops->power_on ? ops->power_on(phy) : 0;
 }
 
 int generic_phy_power_off(struct phy *phy)
 {
-	struct phy_ops const *ops = phy_dev_ops(phy->dev);
+	struct phy_ops const *ops;
+
+	if (!phy)
+		return 0;
+	ops = phy_dev_ops(phy->dev);
 
 	return ops->power_off ? ops->power_off(phy) : 0;
 }
diff --git a/include/generic-phy.h b/include/generic-phy.h
index 947c582..95caf58 100644
--- a/include/generic-phy.h
+++ b/include/generic-phy.h
@@ -270,7 +270,7 @@
  */
 static inline bool generic_phy_valid(struct phy *phy)
 {
-	return phy->dev != NULL;
+	return phy && phy->dev;
 }
 
 #endif /*__GENERIC_PHY_H */