dm: clk: Define clk_get_parent() for clk operations

This commit adds the clk_get_parent() function, which is responsible
for getting the parent's struct clock pointer.

U-Boot's DM support for getting parent is different (the parent
relationship is in udevice) than the one in Common Clock Framework [CCF]
in Linux. To obtain the pointer to struct clk of parent the
pdev->uclass_priv field is read via dev_get_clk_ptr() wrapper.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Peng Fan <peng.fan@nxp.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/clk.h b/include/clk.h
index b10c0013b1..e20641ee98 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -259,6 +259,15 @@ int clk_free(struct clk *clk);
 ulong clk_get_rate(struct clk *clk);
 
 /**
+ * clk_get_parent() - Get current clock's parent.
+ *
+ * @clk:	A clock struct that was previously successfully requested by
+ *		clk_request/get_by_*().
+ * @return pointer to parent's struct clk, or error code passed as pointer
+ */
+struct clk *clk_get_parent(struct clk *clk);
+
+/**
  * clk_set_rate() - Set current clock rate.
  *
  * @clk:	A clock struct that was previously successfully requested by