[PATCH v3 2/4] phy: Add API for devm_of_phy_optional_get_by_index

[Aswath Govindraju]

Add API for devm_of_phy_optional_get_by_index, to obtain a reference to an
optional phy by index.

Signed-off-by: Aswath Govindraju <a-govindraju@xxxxxx>
---
 drivers/phy/phy-core.c  | 26 ++++++++++++++++++++++++++
 include/linux/phy/phy.h |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index ccb575b13777..bf06d4e0ede2 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -839,6 +839,32 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(devm_of_phy_get);
 
+/**
+ * devm_of_phy_optional_get_by_index() - lookup and obtain a reference to an optional 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(), then gets a refcount to it,
+ * and associates a device with it using devres. On driver detach,
+ * release function is invoked on the devres data, then,
+ * devres data is freed. This differs to devm_of_phy_get_by_index() in
+ * that if the phy does not exist, it is not considered an error and
+ * -ENODEV will not be returned. Instead the NULL phy is returned,
+ * which can be passed to all other phy consumer calls.
+ */
+struct phy *devm_of_phy_optional_get_by_index(struct device *dev, struct device_node *np,
+					      int index)
+{
+	struct phy *phy = devm_of_phy_get_by_index(dev, np, index);
+
+	if (PTR_ERR(phy) == -ENODEV)
+		phy = NULL;
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(devm_of_phy_optional_get_by_index);
+
 /**
  * devm_of_phy_get_by_index() - lookup and obtain a reference to a phy by index.
  * @dev: device that requests this phy
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index f3286f4cd306..c5f32b4fadd6 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -253,6 +253,8 @@ struct phy *devm_of_phy_get(struct device *dev, struct device_node *np,
 			    const char *con_id);
 struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
 				     int index);
+struct phy *devm_of_phy_optional_get_by_index(struct device *dev, struct device_node *np,
+					      int index);
 void of_phy_put(struct phy *phy);
 void phy_put(struct device *dev, struct phy *phy);
 void devm_phy_put(struct device *dev, struct phy *phy);
-- 
2.17.1