linux-kernel - Re: [PATCH] rtc: ds1307: Fix relying on reset value for weekday

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Message-ID: <20160708142554.GI22202@piout.net>
Date:	Fri, 8 Jul 2016 16:25:54 +0200
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Keerthy <j-keerthy@...com>
Cc:	a.zummo@...ertech.it, nm@...com, rtc-linux@...glegroups.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: ds1307: Fix relying on reset value for weekday

On 01/06/2016 at 16:19:07 +0530, Keerthy wrote :
> The reset value of weekday is 0x1. This is wrong since
> the reset values of the day/month/year make up to Jan 1 2001.
> When computed weekday comes out to be Monday. On a scale
> of 1-7(Sunday - Saturday) it should be 0x2. So we should not
> be relying on the reset value.
> 
> Hence compute the wday using the current date/month/year values.
> Check if reset wday is any different from the computed wday,
> If different then set the wday which we computed using
> date/month/year values.
> 
> Document Referred:
> http://ww1.microchip.com/downloads/en/DeviceDoc/20002266F.pdf
> 
> Fixes: 1d1945d261a2af "drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips"
> Signed-off-by: Keerthy <j-keerthy@...com>
> ---
>  drivers/rtc/rtc-ds1307.c | 28 +++++++++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
> 
Applied, thanks.

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