[PATCH v9 07/22] clk: Add API to get index of the clock parent

[Sowjanya Komatineni]

This patch adds an API clk_hw_get_parent_index to get index of the
clock parent to use during the clock restore operations on system
resume.

Reviewed-by: Thierry Reding <treding@xxxxxxxxxx>
Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
 drivers/clk/clk.c            | 17 +++++++++++++++++
 include/linux/clk-provider.h |  1 +
 2 files changed, 18 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index cbcc333aec84..12ad0e9b8591 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1645,6 +1645,23 @@ static int clk_fetch_parent_index(struct clk_core *core,
 	return i;
 }
 
+/**
+ * clk_hw_get_parent_index - return the index of parent clock
+ * @hw: clk_hw associated with the clk being consumed
+ * @parent_hw: clk_hw associated with the parent of clk
+ *
+ * Fetches and returns the index of parent clock.
+ * If hw or parent_hw is NULL, returns -EINVAL.
+ */
+int clk_hw_get_parent_index(struct clk_hw *hw, struct clk_hw *parent_hw)
+{
+	if (!hw || !parent_hw)
+		return -EINVAL;
+
+	return clk_fetch_parent_index(hw->core, parent_hw->core);
+}
+EXPORT_SYMBOL_GPL(clk_hw_get_parent_index);
+
 /*
  * 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 dce5521a9bf6..cce830780900 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -817,6 +817,7 @@ 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_parent_index(struct clk_hw *hw, struct clk_hw *parent_hw);
 int clk_hw_set_parent(struct clk_hw *hw, struct clk_hw *new_parent);
 unsigned int __clk_get_enable_count(struct clk *clk);
 unsigned long clk_hw_get_rate(const struct clk_hw *hw);
-- 
2.7.4