linux-kernel - Re: [PATCH 1/1] rtc: ds1685: correct check of day of month

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Message-ID: <20160520223829.GA4963@piout.net>
Date:	Sat, 21 May 2016 00:38:29 +0200
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Heinrich Schuchardt <xypron.glpk@....de>
Cc:	Joshua Kinard <kumba@...too.org>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] rtc: ds1685: correct check of day of month

Hi,

On 18/05/2016 at 21:09:29 +0200, Heinrich Schuchardt wrote :
> Operator ! has a higher priority than &&.
> (!(mday >= 1) && (mday <= 31)) is false for mday == 32.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@....de>
> ---
>  drivers/rtc/rtc-ds1685.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-ds1685.c b/drivers/rtc/rtc-ds1685.c
> index b3ce3c6..b4fae3c 100644
> --- a/drivers/rtc/rtc-ds1685.c
> +++ b/drivers/rtc/rtc-ds1685.c
> @@ -389,7 +389,7 @@ ds1685_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  	ds1685_rtc_end_data_access(rtc);
>  
>  	/* Check month date. */
> -	if (!(mday >= 1) && (mday <= 31))
> +	if ((mday < 1) || (mday > 31))
>  		return -EDOM;
>  

This is a good catch but I think this also breaks the bcd_mode == 1
case because the test happens after the bin2bcd conversion. Can you
check/fix? 

>  	/*
> @@ -461,7 +461,7 @@ ds1685_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  				     RTC_MDAY_BCD_MASK);
>  
>  	/* Check the month date for validity. */
> -	if (!(mday >= 1) && (mday <= 31))
> +	if ((mday < 1) || (mday > 31))
>  		return -EDOM;
>  
>  	/*

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