NULL struct clk pointers should be treated just as the Linux kernel clk
driver does [1]. The reasoning should also apply to the parent clk
argument.
A NULL struct clk pointer can happen for example on the Freescale i.MX6
SABRE Smart Device Board if CONFIG_DRIVER_VIDEO_IMX_IPUV3 is disabled,
leading to assigned-clocks IMX6QDL_CLK_LDB_DI0_SEL and
IMX6QDL_CLK_LDB_DI1_SEL [2] being unavailable. Without this patch, the
board hangs while setting those assigned clock configurations since [3].
[1] 89ac8d7ae1cd ("clk: handle NULL struct clk gracefully")
[2] dts/src/arm/imx6qdl-sabresd.dtsi
[3] f5eb5fddb4 ("clk: fix of clk set defaults when dev is a clk provider")
Signed-off-by: Bastian Krause <bst@xxxxxxxxxxxxxx>
---
drivers/clk/clk.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8e317b4b05..efb5d4ad4a 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -230,7 +230,10 @@ int clk_set_parent(struct clk *clk, struct clk *newparent)
{
struct clk_hw *hw;
int i, ret;
- struct clk *curparent = clk_get_parent(clk);
+ struct clk *curparent;
+
+ if (!clk || !newparent)
+ return 0;
if (IS_ERR(clk))
return PTR_ERR(clk);
@@ -254,6 +257,8 @@ int clk_set_parent(struct clk *clk, struct clk *newparent)
if (i == clk->num_parents)
return -EINVAL;
+ curparent = clk_get_parent(clk);
+
if (clk->enable_count)
clk_enable(newparent);
--
2.30.2
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