phy: core: Add devm_of_phy_get_by_index to phy-core

Some generic drivers, such as ehci, may use multiple phys and for such
drivers referencing phy(s) by name(s) does not make sense. Instead of
inventing new naming schemes and using custom code to iterate through them,
such drivers are better of using nameless phy bindings and using this newly
introduced API to iterate through them.

Signed-off-by: Arun Ramamurthy <[email protected]>
Reviewed-by: Ray Jui <[email protected]>
Reviewed-by: Scott Branden <[email protected]>
[[email protected]: fix compilation errors]
Signed-off-by: Kishon Vijay Abraham I <[email protected]>

drivers/phy/phy-core.c

@@ -622,6 +622,38 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(devm_of_phy_get);
 
+/**
+ * devm_of_phy_get_by_index() - lookup and obtain a reference to a phy by index.
+ * @dev: device that requests this phy
+ * @np: node containing the phy
+ * @index: index of the phy
+ *
+ * Gets the phy using _of_phy_get(), and associates a device with it using
+ * devres. On driver detach, release function is invoked on the devres data,
+ * then, devres data is freed.
+ *
+ */
+struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
+				     int index)
+{
+	struct phy **ptr, *phy;
+
+	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	phy = _of_phy_get(np, index);
+	if (!IS_ERR(phy)) {
+		*ptr = phy;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(devm_of_phy_get_by_index);
+
 /**
  * phy_create() - create a new phy
  * @dev: device that is creating the new phy