[PATCH v4 01/18] clk: introduce clk_hw_get_index_of_parent new API

[Ansuel Smith <ansuelsmth@gmail.com>]

Clk can have multiple parents. Some clk may require to get the cached
index of other parent that are not current associated with the clk.
We have clk_hw_get_parent_index() that returns the index of the current
parent but we can't get the index of other parents of the provided clk.
Introduce clk_hw_get_index_of_parent() to get the cached index of the
parent of the provided clk. This permits a direct access of the internal
clk_fetch_parent_index().

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
 drivers/clk/clk.c            | 14 ++++++++++++++
 include/linux/clk-provider.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8de6a22498e7..bdd70a88394c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1726,6 +1726,20 @@ int clk_hw_get_parent_index(struct clk_hw *hw)
 }
 EXPORT_SYMBOL_GPL(clk_hw_get_parent_index);
 
+/**
+ * clk_hw_get_index_of_parent - return the index of the parent clock
+ * @hw: clk_hw associated with the clk being consumed
+ * @parent: clk_hw of the parent to be fetched the index of
+ *
+ * Fetches and returns the index of parent clock provided.
+ * Returns -EINVAL if the given parent index can't be provided.
+ */
+int clk_hw_get_index_of_parent(struct clk_hw *hw, const struct clk_hw *parent)
+{
+	return clk_fetch_parent_index(hw->core, parent->core);
+}
+EXPORT_SYMBOL_GPL(clk_hw_get_index_of_parent);
+
 /*
  * Update the orphan status of @core and all its children.
  */
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 2faa6f7aa8a8..5708c0b3ef1c 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1198,6 +1198,7 @@ unsigned int clk_hw_get_num_parents(const struct clk_hw *hw);
 struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw);
 struct clk_hw *clk_hw_get_parent_by_index(const struct clk_hw *hw,
 					  unsigned int index);
+int clk_hw_get_index_of_parent(struct clk_hw *hw, const struct clk_hw *parent);
 int clk_hw_get_parent_index(struct clk_hw *hw);
 int clk_hw_set_parent(struct clk_hw *hw, struct clk_hw *new_parent);
 unsigned int __clk_get_enable_count(struct clk *clk);
-- 
2.34.1