RE: [PATCH] staging/comedi/dt282x: avoid integer overflow warning

From: Hartley Sweeten
Date: Tue Mar 15 2016 - 17:50:31 EST


On Monday, March 14, 2016 3:48 PM, Arnd Bergmann wrote:
> gcc-6 warns about passing negative signed integer into swab16()
> in the dt282x driver:

<snip>

> The warning makes sense, though the code is correct as far as I
> can tell.
>
> This disambiguates the operation by making the constant expressions
> we pass here explicitly 'unsigned', which helps to avoid the warning.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> drivers/staging/comedi/drivers/dt282x.c | 62 ++++++++++++++++-----------------
> 1 file changed, 31 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
> index 40bf00984fa5..d4d45c759c62 100644
> --- a/drivers/staging/comedi/drivers/dt282x.c
> +++ b/drivers/staging/comedi/drivers/dt282x.c
> @@ -69,48 +69,48 @@
> * Register map
> */
> #define DT2821_ADCSR_REG 0x00
> -#define DT2821_ADCSR_ADERR (1 << 15)
> -#define DT2821_ADCSR_ADCLK (1 << 9)
> -#define DT2821_ADCSR_MUXBUSY (1 << 8)
> -#define DT2821_ADCSR_ADDONE (1 << 7)
> -#define DT2821_ADCSR_IADDONE (1 << 6)
> +#define DT2821_ADCSR_ADERR (1u << 15)

Changing all of these to use the BIT() macro should also avoid the warning.

Hartley