1 files changed, 22 insertions, 16 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 687b00d67c8a..9a1eb0cfa95f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -850,18 +850,21 @@ static void clk_change_rate(struct clk *clk)
 {
 	struct clk *child;
 	unsigned long old_rate;
+	unsigned long best_parent_rate = 0;
 	struct hlist_node *tmp;
 
 	old_rate = clk->rate;
 
+	if (clk->parent)
+		best_parent_rate = clk->parent->rate;
+
 	if (clk->ops->set_rate)
-		clk->ops->set_rate(clk->hw, clk->new_rate, clk->parent->rate);
+		clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
 
 	if (clk->ops->recalc_rate)
-		clk->rate = clk->ops->recalc_rate(clk->hw,
-				clk->parent->rate);
+		clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
 	else
-		clk->rate = clk->parent->rate;
+		clk->rate = best_parent_rate;
 
 	if (clk->notifier_count && old_rate != clk->rate)
 		__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
@@ -999,7 +1002,7 @@ static struct clk *__clk_init_parent(struct clk *clk)
 
 	if (!clk->parents)
 		clk->parents =
-			kmalloc((sizeof(struct clk*) * clk->num_parents),
+			kzalloc((sizeof(struct clk*) * clk->num_parents),
 					GFP_KERNEL);
 
 	if (!clk->parents)
@@ -1064,21 +1067,24 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
 
 	old_parent = clk->parent;
 
-	/* find index of new parent clock using cached parent ptrs */
-	for (i = 0; i < clk->num_parents; i++)
-		if (clk->parents[i] == parent)
-			break;
+	if (!clk->parents)
+		clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
+								GFP_KERNEL);
 
 	/*
-	 * find index of new parent clock using string name comparison
-	 * also try to cache the parent to avoid future calls to __clk_lookup
+	 * find index of new parent clock using cached parent ptrs,
+	 * or if not yet cached, use string name comparison and cache
+	 * them now to avoid future calls to __clk_lookup.
 	 */
-	if (i == clk->num_parents)
-		for (i = 0; i < clk->num_parents; i++)
-			if (!strcmp(clk->parent_names[i], parent->name)) {
+	for (i = 0; i < clk->num_parents; i++) {
+		if (clk->parents && clk->parents[i] == parent)
+			break;
+		else if (!strcmp(clk->parent_names[i], parent->name)) {
+			if (clk->parents)
 				clk->parents[i] = __clk_lookup(parent->name);
-				break;
-			}
+			break;
+		}
+	}
 
 	if (i == clk->num_parents) {
 		pr_debug("%s: clock %s is not a possible parent of clock %s\n",