clk: Only enable the parent clock if the clock was enabled before reparenting

The current implementation of clk_set_parent() unconditionally enables
the new parent clock, even if the target clock was not previously enabled.

To avoid this implicit behavior, this patch adds a check for whether
the target clock has been enabled before parent enabling..

Fixes: ac30d90f336 ("clk: Ensure the parent clocks are enabled while reparenting")
Signed-off-by: Maksim Kiselev <[email protected]>
Reviewed-by: Miquel Raynal <[email protected]>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 3dbe1ce9441..ae787b88510 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -631,10 +631,12 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
 	if (!ops->set_parent)
 		return -ENOSYS;
 
-	ret = clk_enable(parent);
-	if (ret && ret != -ENOSYS) {
-		printf("Cannot enable parent %s\n", parent->dev->name);
-		return ret;
+	if (clk->enable_count) {
+		ret = clk_enable(parent);
+		if (ret && ret != -ENOSYS) {
+			printf("Cannot enable parent %s\n", parent->dev->name);
+			return ret;
+		}
 	}
 
 	ret = ops->set_parent(clk, parent);