linux-kernel - Re: [PATCH 2/2] rtc: add rtc-abx80x, a driver for the Abracon AB x80x i2c rtc

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Message-ID: <20150315151017.GA31712@frolo.macqel>
Date:	Sun, 15 Mar 2015 16:10:17 +0100
From:	Philippe De Muyter <phdm@...qel.be>
To:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH 2/2] rtc: add rtc-abx80x, a driver for the Abracon AB
	x80x i2c rtc

On Sat, Mar 14, 2015 at 07:09:11PM +0100, Alexandre Belloni wrote:
> On 14/03/2015 at 13:44:41 +0100, Philippe De Muyter wrote :
> > > +	tm->tm_sec = bcd2bin(date[ABX8XX_REG_SC] & 0x7F);
> > > +	tm->tm_min = bcd2bin(date[ABX8XX_REG_MN] & 0x7F);
> > > +	tm->tm_hour = bcd2bin(date[ABX8XX_REG_HR] & 0x3F);
> > > +	tm->tm_wday = date[ABX8XX_REG_WD] & 0x7;
> > > +	tm->tm_mday = bcd2bin(date[ABX8XX_REG_DA] & 0x3F);
> > > +	tm->tm_mon = bcd2bin(date[ABX8XX_REG_MO] & 0x1F) - 1;
> > > +	tm->tm_year = bcd2bin(date[ABX8XX_REG_YR]);
> > > +	if (tm->tm_year < 70)
> > 
> > Is that still useful for a driver written in 2015 ?
> > 
> 
> I'd say that this is actually the only correct way to do it. Only dates
> before 01/01/1970 00:00 are considered invalid. So, unless adding a
> check like:
> 
> if (tm->tm_year < 100)
> 	return -EINVAL;
> 
> in abx80x_rtc_set_time, setting and then reading a date before 2000 will
> fail silently. I'm open to add that check.

You are right.  It is actually more a consistency problem between rtc
drivers and thus a question for the rtc-subsytem maintainer.

Philippe

-- 
Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140 Bruxelles
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