clk: abstract parent cache

Abstract access to the clock parent cache by defining
clk_get_parent_by_index(clk, index). This allows access to parent
clocks from clock drivers.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/clk.c

@@ -559,6 +559,19 @@ struct clk *__clk_get_parent(struct clk *clk)
 	return !clk ? NULL : clk->parent;
 }
 
+struct clk *clk_get_parent_by_index(struct clk *clk, u8 index)
+{
+	if (!clk || index >= clk->num_parents)
+		return NULL;
+	else if (!clk->parents)
+		return __clk_lookup(clk->parent_names[index]);
+	else if (!clk->parents[index])
+		return clk->parents[index] =
+			__clk_lookup(clk->parent_names[index]);
+	else
+		return clk->parents[index];
+}
+
 unsigned int __clk_get_enable_count(struct clk *clk)
 {
 	return !clk ? 0 : clk->enable_count;
@@ -1316,13 +1329,7 @@ static struct clk *__clk_init_parent(struct clk *clk)
 			kzalloc((sizeof(struct clk*) * clk->num_parents),
 					GFP_KERNEL);
 
-	if (!clk->parents)
-		ret = __clk_lookup(clk->parent_names[index]);
-	else if (!clk->parents[index])
-		ret = clk->parents[index] =
-			__clk_lookup(clk->parent_names[index]);
-	else
-		ret = clk->parents[index];
+	ret = clk_get_parent_by_index(clk, index);
 
 out:
 	return ret;

include/linux/clk-provider.h

@@ -420,6 +420,7 @@ const char *__clk_get_name(struct clk *clk);
 struct clk_hw *__clk_get_hw(struct clk *clk);
 u8 __clk_get_num_parents(struct clk *clk);
 struct clk *__clk_get_parent(struct clk *clk);
+struct clk *clk_get_parent_by_index(struct clk *clk, u8 index);
 unsigned int __clk_get_enable_count(struct clk *clk);
 unsigned int __clk_get_prepare_count(struct clk *clk);
 unsigned long __clk_get_rate(struct clk *clk);