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

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

[Arnd Bergmann]

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@arndb.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

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

[Henry Chen]

Hi,

Thanks to the patch.

On Thu, 2016-05-12 at 23:01 +0200, Arnd Bergmann wrote:
> 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@arndb.de>

Acked-by: Henry Chen <henryc.chen@mediatek.com>

> ---
>  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,