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>
---
Changes since (implicit) v1:
- make clk_get_parent(NULL) return NULL
- undo shifting call to clk_get_parent() in clk_set_parent()
---
drivers/clk/clk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8e317b4b05..52e309e877 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -232,6 +232,9 @@ int clk_set_parent(struct clk *clk, struct clk *newparent)
int i, ret;
struct clk *curparent = clk_get_parent(clk);
+ if (!clk || !newparent)
+ return 0;
+
if (IS_ERR(clk))
return PTR_ERR(clk);
if (IS_ERR(newparent))
@@ -287,7 +290,7 @@ struct clk *clk_get_parent(struct clk *clk)
struct clk_hw *hw;
int idx;
- if (IS_ERR(clk))
+ if (IS_ERR_OR_NULL(clk))
return clk;
if (!clk->num_parents)
--
2.30.2
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