clk: handle NULL struct clk gracefully

At some point changes to clk_set_rate and clk_set_parent introduced a
bug whereby NULL struct clk pointers were treated as an error. This is
in violation of the API in include/linux/clk.h. Reintroduce graceful
handling of NULL clk's by bailing from clk_set_rate and clk_set_parent
with return codes of zero.

Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index bc020372106b..7c4376289865 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1428,6 +1428,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
         struct clk *top, *fail_clk;
         int ret = 0;
 
+        if (!clk)
+                return 0;
+
         /* prevent racing with updates to the clock topology */
         clk_prepare_lock();
 
@@ -1567,7 +1570,10 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
         u8 p_index = 0;
         unsigned long p_rate = 0;
 
-        if (!clk || !clk->ops)
+        if (!clk)
+                return 0;
+
+        if (!clk->ops)
                 return -EINVAL;
 
         /* verify ops for for multi-parent clks */