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Subject[PATCH AUTOSEL 4.20 09/77] clk: vc5: Abort clock configuration without upstream clock
From: Marek Vasut <>

[ Upstream commit 2137a109a5e39c2bdccfffe65230ed3fadbaac0e ]

In case the upstream clock are not set, which can happen in case the
VC5 has no valid upstream clock, the $src variable is used uninited
by regmap_update_bits(). Check for this condition and return -EINVAL
in such case.

Note that in case the VC5 has no valid upstream clock, the VC5 can
not operate correctly. That is a hardware property of the VC5. The
internal oscilator present in some VC5 models is also considered
upstream clock.

Signed-off-by: Marek Vasut <>
Cc: Alexey Firago <>
Cc: Laurent Pinchart <>
Cc: Stephen Boyd <>
[ Added comment about probe preventing this from
happening in the first place]
Signed-off-by: Stephen Boyd <>
Signed-off-by: Sasha Levin <>
drivers/clk/clk-versaclock5.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
index decffb3826ec..a738af893532 100644
--- a/drivers/clk/clk-versaclock5.c
+++ b/drivers/clk/clk-versaclock5.c
@@ -262,8 +262,10 @@ static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)

if (vc5->clk_mux_ins == VC5_MUX_IN_XIN)
- if (vc5->clk_mux_ins == VC5_MUX_IN_CLKIN)
+ else if (vc5->clk_mux_ins == VC5_MUX_IN_CLKIN)
+ else /* Invalid; should have been caught by vc5_probe() */
+ return -EINVAL;

return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask, src);
 \ /
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