On Tuesday, March 15, 2016 2:50 PM, Arnd Bergmann wrote: > On Tuesday 15 March 2016 21:35:40 Hartley Sweeten wrote: >> 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 <a...@arndb.de> >>> --- >>> 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. > > Yes, but it won't work for the ones that have more than one bit: > > #define DT2821_SUPCSR_DS_AD_TRIG (3 << 10)
Use a helper macro for those bits: #define DT2821_SUPCSR_DS(x) (((x) & 0x3) << 10) #define DT2821_SUPCSR_DS_PIO DT2821_SUPCSR_DS(0) #define DT2821_SUPCSR_DS_AD_CLK DT2821_SUPCSR_DS(1) #define DT2821_SUPCSR_DS_DA_CLK DT2821_SUPCSR_DS(2) #define DT2821_SUPCSR_DS_AD_TRIG DT2821_SUPCSR_DS(3) > I considered using BIT() but decided against it for consistency. Your change may fix the gcc-6 issue but it doesn't fix the 28 checkpatch.pl issues: CHECK: Prefer using the BIT macro Regards, Hartley
