linux-kernel - [PATCH] soc: mtk-pmic-wrap: avoid integer overflow warning

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Date:	Thu, 12 May 2016 23:01:30 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Matthias Brugger <matthias.bgg@...il.com>
Cc:	Arnd Bergmann <arnd@...db.de>, John Crispin <blogic@...nwrt.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Henry Chen <henryc.chen@...iatek.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] soc: mtk-pmic-wrap: avoid integer overflow warning

On ARM64, the mtk-pmic-wrap driver causes a harmless warning:

mtk-pmic-wrap.c:1062:16: warning: large integer implicitly truncated to unsigned type [-Woverflow]
mtk-pmic-wrap.c:1074:16: warning: large integer implicitly truncated to unsigned type [-Woverflow]
mtk-pmic-wrap.c:1086:16: warning: large integer implicitly truncated to unsigned type [-Woverflow]
  .int_en_all = ~(BIT(31) | BIT(1)),

The problem is that the result of the BIT() macro is an 'unsigned long',
so taking the bitwise NOT operation of that results in an integer
with the upper 32 bits all set and that cannot be assigned to a
'u32' variable without loss of information.

This is harmless because we were never interested in the upper bits
here anyway, so we can shut up the warning by adding a simple cast
to 'u32'.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/soc/mediatek/mtk-pmic-wrap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-pmic-wrap.c b/drivers/soc/mediatek/mtk-pmic-wrap.c
index 3c3e56df526e..a003ba26ca6e 100644
--- a/drivers/soc/mediatek/mtk-pmic-wrap.c
+++ b/drivers/soc/mediatek/mtk-pmic-wrap.c
@@ -1059,7 +1059,7 @@ static const struct pmic_wrapper_type pwrap_mt2701 = {
 	.regs = mt2701_regs,
 	.type = PWRAP_MT2701,
 	.arb_en_all = 0x3f,
-	.int_en_all = ~(BIT(31) | BIT(2)),
+	.int_en_all = ~(u32)(BIT(31) | BIT(2)),
 	.spi_w = PWRAP_MAN_CMD_SPI_WRITE_NEW,
 	.wdt_src = PWRAP_WDT_SRC_MASK_ALL,
 	.has_bridge = 0,
@@ -1071,7 +1071,7 @@ static struct pmic_wrapper_type pwrap_mt8135 = {
 	.regs = mt8135_regs,
 	.type = PWRAP_MT8135,
 	.arb_en_all = 0x1ff,
-	.int_en_all = ~(BIT(31) | BIT(1)),
+	.int_en_all = ~(u32)(BIT(31) | BIT(1)),
 	.spi_w = PWRAP_MAN_CMD_SPI_WRITE,
 	.wdt_src = PWRAP_WDT_SRC_MASK_ALL,
 	.has_bridge = 1,
@@ -1083,7 +1083,7 @@ static struct pmic_wrapper_type pwrap_mt8173 = {
 	.regs = mt8173_regs,
 	.type = PWRAP_MT8173,
 	.arb_en_all = 0x3f,
-	.int_en_all = ~(BIT(31) | BIT(1)),
+	.int_en_all = ~(u32)(BIT(31) | BIT(1)),
 	.spi_w = PWRAP_MAN_CMD_SPI_WRITE,
 	.wdt_src = PWRAP_WDT_SRC_MASK_NO_STAUPD,
 	.has_bridge = 0,
-- 
2.7.0