[PATCH 2/3] clk: Unprepare the unused prepared slow clocks at late init

[Ulf Hansson]

From: Ulf Hansson <ulf.hansson at linaro.org>

The unused ungated fast clocks are already being disabled from
clk_disable_unused at late init. This patch extend this sequence
to the slow unused prepared clocks to be unprepared.

Unless the optional .is_prepared callback is implemented by a
clk_hw the clk_disable_unused sequence will not unprepare any
unused clocks, since it will fall back to use the software
prepare counter.

Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
---
 drivers/clk/clk.c |   29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 5adf2bb..2c4c2a1 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -199,6 +199,29 @@ static inline int clk_debug_register(struct clk *clk) { return 0; }
 #endif
 
 /* caller must hold prepare_lock */
+static void clk_unprepare_unused_subtree(struct clk *clk)
+{
+	struct clk *child;
+	struct hlist_node *tmp;
+
+	if (!clk)
+		return;
+
+	hlist_for_each_entry(child, tmp, &clk->children, child_node)
+		clk_unprepare_unused_subtree(child);
+
+	if (clk->prepare_count)
+		return;
+
+	if (clk->flags & CLK_IGNORE_UNUSED)
+		return;
+
+	if (__clk_is_prepared(clk))
+		if (clk->ops->unprepare)
+			clk->ops->unprepare(clk->hw);
+}
+
+/* caller must hold prepare_lock */
 static void clk_disable_unused_subtree(struct clk *clk)
 {
 	struct clk *child;
@@ -251,6 +274,12 @@ static int clk_disable_unused(void)
 	hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
 		clk_disable_unused_subtree(clk);
 
+	hlist_for_each_entry(clk, tmp, &clk_root_list, child_node)
+		clk_unprepare_unused_subtree(clk);
+
+	hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node)
+		clk_unprepare_unused_subtree(clk);
+
 	mutex_unlock(&prepare_lock);
 
 	return 0;
-- 
1.7.10