From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Nishanth Menon <nm@ti.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>,
linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org,
rtc-linux@googlegroups.com
Subject: Re: [PATCH V2] drivers/rtc/rtc-ds1307.c: Enable the mcp794xx alarm after programming time
Date: Wed, 22 Apr 2015 13:30:53 +0200 [thread overview]
Message-ID: <20150422113053.GI8539@piout.net> (raw)
In-Reply-To: <55370073.3060809@ti.com>
On 21/04/2015 at 20:59:15 -0500, Nishanth Menon wrote :
> >> Why is that so? when set alarm is requested for time X, you want
> >> interrupt at time X, not an interrupt for previous configured RTC
> >> alarm time!
> >>
> >
> > You expect at least an interrupt.
>
> And you will get an interrupt if the event occurs before the i2c burst
> starts. Once the i2cburst does start, you are committing to the new time.
>
You mean that even if ALM0EN is set after ALM0IF was set to 1, it will
trigger the interrupt? I had a look at the MFP output block diagram
would let me think that this is the case. I was thinking otherwise
before. If that is so, then indeed, your patch is OK.
My concern was about the time between ds1307->write_block_data() and
i2c_smbus_write_byte_data() which actually calls cond_sched().
I fully agree that your patch doesn't change the behaviour for the other
cases you presented and further clean up is to be done in a separate set
of patches.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2015-04-22 11:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-21 0:51 [PATCH V2] drivers/rtc/rtc-ds1307.c: Enable the mcp794xx alarm after programming time Nishanth Menon
2015-04-21 23:41 ` Alexandre Belloni
2015-04-21 23:58 ` Nishanth Menon
2015-04-22 1:09 ` Alexandre Belloni
2015-04-22 1:59 ` Nishanth Menon
2015-04-22 11:30 ` Alexandre Belloni [this message]
2015-04-23 0:04 ` Nishanth Menon
2015-04-24 9:41 ` Alexandre Belloni
2015-04-22 13:26 ` Grygorii.Strashko@linaro.org
2015-04-23 0:00 ` Nishanth Menon
2015-04-23 10:17 ` Grygorii.Strashko@linaro.org
2015-04-23 13:11 ` Nishanth Menon
2015-04-23 15:29 ` Grygorii.Strashko@linaro.org
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