linux-kernel - [PATCH] thermal: armada: Fix -Wshift-negative-value

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Message-Id: <20190613184923.245935-1-nhuck@google.com>
Date:   Thu, 13 Jun 2019 11:49:23 -0700
From:   Nathan Huckleberry <nhuck@...gle.com>
To:     miquel.raynal@...tlin.com, rui.zhang@...el.com,
        edubezval@...il.com, daniel.lezcano@...aro.org
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nathan Huckleberry <nhuck@...gle.com>,
        clang-built-linux@...glegroups.com
Subject: [PATCH] thermal: armada: Fix -Wshift-negative-value

Clang produces the following warning

drivers/thermal/armada_thermal.c:270:33: warning: shifting a negative
signed value is undefined [-Wshift-negative-value]
1 warning        reg &= ~CONTROL1_TSEN_AVG_MASK <<
CONTROL1_TSEN_AVG_SHIFT; generated
.
               ~~~~~~~~~~~~~~~~~~~~~~~ ^

CONTROL1_TSEN_AVG_SHIFT is defined to be zero.
Since shifting by zero does nothing this variable can be removed.

Cc: clang-built-linux@...glegroups.com
Link: https://github.com/ClangBuiltLinux/linux/issues/532
Signed-off-by: Nathan Huckleberry <nhuck@...gle.com>
---
 drivers/thermal/armada_thermal.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
index 8c07a393dc2e..709a22f455e9 100644
--- a/drivers/thermal/armada_thermal.c
+++ b/drivers/thermal/armada_thermal.c
@@ -53,7 +53,6 @@
 #define CONTROL0_TSEN_MODE_EXTERNAL	0x2
 #define CONTROL0_TSEN_MODE_MASK		0x3
 
-#define CONTROL1_TSEN_AVG_SHIFT		0
 #define CONTROL1_TSEN_AVG_MASK		0x7
 #define CONTROL1_EXT_TSEN_SW_RESET	BIT(7)
 #define CONTROL1_EXT_TSEN_HW_RESETn	BIT(8)
@@ -267,8 +266,8 @@ static void armada_cp110_init(struct platform_device *pdev,
 
 	/* Average the output value over 2^1 = 2 samples */
 	regmap_read(priv->syscon, data->syscon_control1_off, &reg);
-	reg &= ~CONTROL1_TSEN_AVG_MASK << CONTROL1_TSEN_AVG_SHIFT;
-	reg |= 1 << CONTROL1_TSEN_AVG_SHIFT;
+	reg &= ~CONTROL1_TSEN_AVG_MASK;
+	reg |= 1;
 	regmap_write(priv->syscon, data->syscon_control1_off, reg);
 }
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog