| Message ID | 20170113153311.2611510-3-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jan 13, 2017 at 04:32:53PM +0100, Arnd Bergmann wrote: > -#define PWR_CR_DBP BIT(8) > +#define PWR_CR_DBP (u32)BIT(8) Shouldn't that have parens around it as it's no longer a simple expression.
On 13/01/2017 at 15:52:29 +0000, Russell King - ARM Linux wrote : > On Fri, Jan 13, 2017 at 04:32:53PM +0100, Arnd Bergmann wrote: > > -#define PWR_CR_DBP BIT(8) > > +#define PWR_CR_DBP (u32)BIT(8) > > Shouldn't that have parens around it as it's no longer a simple expression. > Yes, at least checkpatch complains about it.
Hi Arnd, On 01/13/2017 04:32 PM, Arnd Bergmann wrote: > Using the ~ operator on a BIT() constant results in a large 'unsigned long' > constant that won't fit into an 'unsigned int' function argument on 64-bit > architectures, resulting in a harmless build warning in x86 allmodconfig: > > drivers/rtc/rtc-stm32.c: In function 'stm32_rtc_probe': > drivers/rtc/rtc-stm32.c:651:51: error: large integer implicitly truncated to unsigned type [-Werror=overflow] > regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); I thought I would fix this warning by replacing all ~PWR_CR_DBP by 0, because the mask PWR_CR_DBP prevents other bits to be cleared. In this way, I avoid the ugly cast... > > This works around the warning by adding an explict cast to 'u32', but > that is unfortunately a bit ugly and I feel there should be a better > way to do this, possibly with some changes to either the bitops.h > header or the regmap API. > > Cc: Mark Brown <broonie@kernel.org> > Fixes: 4e64350f42e2 ("rtc: add STM32 RTC driver") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/rtc/rtc-stm32.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c > index 8c599f52124c..05d3dc89e55f 100644 > --- a/drivers/rtc/rtc-stm32.c > +++ b/drivers/rtc/rtc-stm32.c > @@ -92,7 +92,7 @@ > /* STM32_PWR_CR */ > #define PWR_CR 0x00 > /* STM32_PWR_CR bit field */ > -#define PWR_CR_DBP BIT(8) > +#define PWR_CR_DBP (u32)BIT(8) > > struct stm32_rtc { > struct rtc_device *rtc_dev; > Regards, Amelie
On Fri, Jan 13, 2017 at 4:56 PM, Amelie DELAUNAY <amelie.delaunay@st.com> wrote: > On 01/13/2017 04:32 PM, Arnd Bergmann wrote: >> >> Using the ~ operator on a BIT() constant results in a large 'unsigned >> long' >> constant that won't fit into an 'unsigned int' function argument on 64-bit >> architectures, resulting in a harmless build warning in x86 allmodconfig: >> >> drivers/rtc/rtc-stm32.c: In function 'stm32_rtc_probe': >> drivers/rtc/rtc-stm32.c:651:51: error: large integer implicitly truncated >> to unsigned type [-Werror=overflow] >> regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); > > I thought I would fix this warning by replacing all ~PWR_CR_DBP by 0, > because the mask PWR_CR_DBP prevents other bits to be cleared. > In this way, I avoid the ugly cast... Good idea, much nicer than mine! Can you send that patch? Arnd
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c index 8c599f52124c..05d3dc89e55f 100644 --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -92,7 +92,7 @@ /* STM32_PWR_CR */ #define PWR_CR 0x00 /* STM32_PWR_CR bit field */ -#define PWR_CR_DBP BIT(8) +#define PWR_CR_DBP (u32)BIT(8) struct stm32_rtc { struct rtc_device *rtc_dev;
Using the ~ operator on a BIT() constant results in a large 'unsigned long' constant that won't fit into an 'unsigned int' function argument on 64-bit architectures, resulting in a harmless build warning in x86 allmodconfig: drivers/rtc/rtc-stm32.c: In function 'stm32_rtc_probe': drivers/rtc/rtc-stm32.c:651:51: error: large integer implicitly truncated to unsigned type [-Werror=overflow] regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); This works around the warning by adding an explict cast to 'u32', but that is unfortunately a bit ugly and I feel there should be a better way to do this, possibly with some changes to either the bitops.h header or the regmap API. Cc: Mark Brown <broonie@kernel.org> Fixes: 4e64350f42e2 ("rtc: add STM32 RTC driver") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/rtc/rtc-stm32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)