From 2137a109a5e39c2bdccfffe65230ed3fadbaac0e Mon Sep 17 00:00:00 2001
From: Marek Vasut <marek.vasut@gmail.com>
Date: Sat, 15 Dec 2018 01:55:19 +0100
Subject: [PATCH] clk: vc5: Abort clock configuration without upstream clock
Git-commit: 2137a109a5e39c2bdccfffe65230ed3fadbaac0e
Patch-mainline: v5.0-rc4
References: bsc#1051510

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 <marek.vasut+renesas@gmail.com>
Cc: Alexey Firago <alexey_firago@mentor.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-renesas-soc@vger.kernel.org
[sboyd@kernel.org: Added comment about probe preventing this from
happening in the first place]

Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 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 5b393e711e94..7d16ab0784ec 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)
 			src = VC5_PRIM_SRC_SHDN_EN_XTAL;
-		if (vc5->clk_mux_ins == VC5_MUX_IN_CLKIN)
+		else if (vc5->clk_mux_ins == VC5_MUX_IN_CLKIN)
 			src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
+		else /* Invalid; should have been caught by vc5_probe() */
+			return -EINVAL;
 	}
 
 	return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask, src);
-- 
2.16.4