Re: [PATCH] rtc: stm32: use 0 instead of ~PWR_CR_DBP in regmap_update_bits

[Alexandre Belloni]

On 16/01/2017 at 09:57:38 +0100, Amelie Delaunay 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);
> 
> As PWR_CR_DBP mask prevents other bits to be cleared, replace all
> ~PWR_CR_DBP by 0.
> 
> Fixes: 4e64350f42e2 ("rtc: add STM32 RTC driver")
> Signed-off-by: Arnd Bergmann 
> Signed-off-by: Amelie Delaunay 
> ---
Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[PATCH] rtc: stm32: use 0 instead of ~PWR_CR_DBP in regmap_update_bits

[Amelie Delaunay]

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);

As PWR_CR_DBP mask prevents other bits to be cleared, replace all
~PWR_CR_DBP by 0.

Fixes: 4e64350f42e2 ("rtc: add STM32 RTC driver")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Amelie Delaunay 
---
 drivers/rtc/rtc-stm32.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
index 8c599f5..03c97c1 100644
--- a/drivers/rtc/rtc-stm32.c
+++ b/drivers/rtc/rtc-stm32.c
@@ -648,7 +648,7 @@ static int stm32_rtc_probe(struct platform_device *pdev)
 err:
clk_disable_unprepare(rtc->ck_rtc);
 
-   regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP);
+   regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0);
 
device_init_wakeup(&pdev->dev, false);
 
@@ -670,7 +670,7 @@ static int stm32_rtc_remove(struct platform_device *pdev)
clk_disable_unprepare(rtc->ck_rtc);
 
/* Enable backup domain write protection */
-   regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP);
+   regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0);
 
device_init_wakeup(&pdev->dev, false);
 
-- 
1.9.1