clk: prevent spurious parent rate propagation
Patch 'clk: always pass parent_rate into .round_rate' made a subtle
change to the semantics of .round_rate. It is now expected for the
parent's rate to always be passed in, simplifying the implemenation of
various .round_rate callback definitions.
However the patch also introduced a bug in clk_calc_new_rates whereby a
clock without the CLK_SET_RATE_PARENT flag set could still propagate a
rate change up to a parent clock if the the .round_rate callback
modified the &best_parent_rate value in any way.
This patch fixes the issue at the framework level (in
clk_calc_new_rates) by specifically handling the case where the
CLK_SET_RATE_PARENT flag is not set.
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8149764..7ceca0e 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -774,12 +774,18 @@
if (IS_ERR_OR_NULL(clk))
return NULL;
+ /* save parent rate, if it exists */
+ if (clk->parent)
+ best_parent_rate = clk->parent->rate;
+
/* never propagate up to the parent */
if (!(clk->flags & CLK_SET_RATE_PARENT)) {
if (!clk->ops->round_rate) {
clk->new_rate = clk->rate;
return NULL;
}
+ new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
+ goto out;
}
/* need clk->parent from here on out */
@@ -795,7 +801,6 @@
goto out;
}
- best_parent_rate = clk->parent->rate;
new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
if (best_parent_rate != clk->parent->rate) {