[PATCH 3/3] clk: Introduce optional unprepare_unused callback

[Ulf Hansson]

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

An unprepare_unused callback is introduced due to the same reasons to
why the disable_unused callback was added.

During the clk_disable_unused sequence, those clk_hw that needs specific
treatment with regards to being unprepared, shall implement the
unprepare_unused callback.

Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
---
 drivers/clk/clk.c            |    7 +++++--
 include/linux/clk-provider.h |    5 +++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 2c4c2a1..81437cf 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -216,9 +216,12 @@ static void clk_unprepare_unused_subtree(struct clk *clk)
 	if (clk->flags & CLK_IGNORE_UNUSED)
 		return;
 
-	if (__clk_is_prepared(clk))
-		if (clk->ops->unprepare)
+	if (__clk_is_prepared(clk)) {
+		if (clk->ops->unprepare_unused)
+			clk->ops->unprepare_unused(clk->hw);
+		else if (clk->ops->unprepare)
 			clk->ops->unprepare(clk->hw);
+	}
 }
 
 /* caller must hold prepare_lock */
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 86ff6be..9e97fb4 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -49,6 +49,10 @@ struct clk_hw;
  *		This function is allowed to sleep. Optional, if this op is not
  *		set then the prepare count will be used.
  *
+ * @unprepare_unused: Unprepare the clock atomically.  Only called from
+ *		clk_disable_unused for prepare clocks with special needs.
+ *		Called with prepare mutex held. This function may sleep.
+ *
  * @enable:	Enable the clock atomically. This must not return until the
  * 		clock is generating a valid clock signal, usable by consumer
  * 		devices. Called with enable_lock held. This function must not
@@ -113,6 +117,7 @@ struct clk_ops {
 	int		(*prepare)(struct clk_hw *hw);
 	void		(*unprepare)(struct clk_hw *hw);
 	int		(*is_prepared)(struct clk_hw *hw);
+	void		(*unprepare_unused)(struct clk_hw *hw);
 	int		(*enable)(struct clk_hw *hw);
 	void		(*disable)(struct clk_hw *hw);
 	int		(*is_enabled)(struct clk_hw *hw);
-- 
1.7.10