[RFC/RFT v3 02/14] clk: core: introduce clk_hw_set_parent()

[Neil Armstrong <narmstrong@xxxxxxxxxxxx>]

Introduce the clk_hw_set_parent() provider call to change parent of
a clock by using the clk_hw pointers.

This eases the clock reparenting from clock rate notifiers and
implementing DVFS with simpler code avoiding the boilerplates
functions as __clk_lookup(clk_hw_get_name()) then clk_set_parent().

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
 drivers/clk/clk.c            | 6 ++++++
 include/linux/clk-provider.h | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index aa51756fd4d6..06e1abe3391c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2490,6 +2490,12 @@ static int clk_core_set_parent_nolock(struct clk_core *core,
 	return ret;
 }
 
+int clk_hw_set_parent(struct clk_hw *hw, struct clk_hw *parent)
+{
+	return clk_core_set_parent_nolock(hw->core, parent->core);
+}
+EXPORT_SYMBOL_GPL(clk_hw_set_parent);
+
 /**
  * clk_set_parent - switch the parent of a mux clk
  * @clk: the mux clk whose input we are switching
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index bb6118f79784..8a453380f9a4 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -812,6 +812,7 @@ 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_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);
 unsigned long __clk_get_flags(struct clk *clk);
-- 
2.21.0