clk: clk_set_parent() with current parent shouldn't fail
If a driver calls clk_set_parent(clk, parent) and parent is the
current parent of clk we shouldn't fail in any case.
Unfortunately if clk is a read-only mux we return -ENOSYS
because we think we can't change the parent, except for in this
special case where we don't actually need to change the parent at
all. Return 0 in such a situation.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 42064ce..3e10cdf 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2055,16 +2055,18 @@
if (!clk)
return 0;
- /* verify ops for for multi-parent clks */
- if ((clk->num_parents > 1) && (!clk->ops->set_parent))
- return -ENOSYS;
-
/* prevent racing with updates to the clock topology */
clk_prepare_lock();
if (clk->parent == parent)
goto out;
+ /* verify ops for for multi-parent clks */
+ if ((clk->num_parents > 1) && (!clk->ops->set_parent)) {
+ ret = -ENOSYS;
+ goto out;
+ }
+
/* check that we are allowed to re-parent if the clock is in use */
if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
ret = -EBUSY;