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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Marek Vasut <marek.vasut@gmail.com>,
        Marek Vasut <marek.vasut+renesas@gmail.com>,
        Alexey Firago <alexey_firago@mentor.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Stephen Boyd <sboyd@kernel.org>,
        linux-renesas-soc@vger.kernel.org, Sasha Levin <sashal@kernel.org>,
        linux-clk@vger.kernel.org
Subject: [PATCH AUTOSEL 4.20 09/77] clk: vc5: Abort clock configuration without upstream clock
Date:   Thu, 14 Feb 2019 21:07:47 -0500
Message-Id: <20190215020855.176727-9-sashal@kernel.org>
In-Reply-To: <20190215020855.176727-1-sashal@kernel.org>
References: <20190215020855.176727-1-sashal@kernel.org>
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From: Marek Vasut <marek.vasut@gmail.com>

[ 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 <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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)
 			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);
-- 
2.19.1