clk: adds support for transition-clock property

The transition-clock property defines a parent clock to be used by
a clock consumer during frequency transitions in variable frequency
clocks. It is specified by referencing a clock (must be a parent clock).

The clock functions clk_set_transition_parent and clk_get_transition_parent
are defined to work with the transition parent in clocks.

The clock function clk_use_transition_mode sets the clock parent to
the specified transition parent.

Signed-off-by: Octav Zlatior <octav.zlatior@theobroma-systems.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/linux/clk.h b/include/linux/clk.h
index 68c16a6bedb3..4c2add0b4819 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -378,6 +378,33 @@ int clk_set_parent(struct clk *clk, struct clk *parent);
 struct clk *clk_get_parent(struct clk *clk);
 
 /**
+ * clk_get_transition_parent - return the transition parent to be used by
+ * a clock
+ * @clk: clock to get transition parent for
+ *
+ * Returns a pointer to the transition parent or NULL if not set
+ */
+struct clk *clk_get_transition_parent(struct clk *clk);
+
+/**
+ * clk_set_transition_parent - set the transition parent to be used by
+ * a clock
+ * @clk: clock to set transition parent for
+ * @parent: clock parent to set as transition parent
+ *
+ * Returns 0 on success or an error code otherwise
+ */
+int clk_set_transition_parent(struct clk *clk, struct clk *parent);
+
+/**
+ * clk_use_transition_mode - set the clock to "transition_mode"
+ * In transition mode, the clock will use the transition parent as parent
+ *
+ * Returns 0 on success or an error code otherwise
+ */
+int clk_use_transition_mode(struct clk *clk);
+
+/**
  * clk_get_sys - get a clock based upon the device name
  * @dev_id: device name
  * @con_id: connection ID