From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: Flavio Suligoi <f.suligoi@asem.it>
Cc: Alessandro Zummo <a.zummo@towertech.it>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"linux-rtc@vger.kernel.org" <linux-rtc@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] rtc: pcf2127: add battery-low INTn generation
Date: Wed, 3 Apr 2019 18:15:29 +0200 [thread overview]
Message-ID: <20190403161529.GS22216@piout.net> (raw)
In-Reply-To: <8367f68a023d468f8235810b0cf583bc@asem.it>
On 03/04/2019 16:09:14+0000, Flavio Suligoi wrote:
> Hi,
>
> > On 03/04/2019 15:49:03+0000, Flavio Suligoi wrote:
> > > > Then, you should probably not enable BLIE because this will cause
> > issues
> > > > with the alarm functionnality.. It is certainly enough to use
> > > > RTC_VL_READ periodically.
> > >
> > > We use the nINT signaling solution because of this pin, in addition
> > > to be used by the CPU, can be also connected to an external connector,
> > > available for the final user.
> > > Anyway, even if the BLIE is set, the sw low voltage alarm works,
> > > with the message (displayed about every 12 minutes):
> > >
> >
> > I agree the DT property makes sense when the nINT pin is not connected
> > to the CPU. But if it is, then you have an issue that nINT will be
> > pulled low until the user changes the battery, meaning that you will
> > not get any alarm interrupt anymore, possibly leading to a system that
> > is not waking up anymore.
>
> Ah, ok, thanks for the info.
> I know this, but in our specific case, this is not a problem,
> since we don't use the nINT for other purposes, but only for
> a battery low indicator. On the contrary, in our case, it's better
> that the alarm signal remains low until the battery is changed.
>
> Anyway, I can specify this collateral effect in a specific file for the
> Pcf2127 in the DT bindings Documentation. What do you think?
>
This is fine as-is, I'll handle that in my series adding alarm support
because there will be no issues until then.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
next prev parent reply other threads:[~2019-04-03 16:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-03 14:52 [PATCH 1/2] dt-bindings: rtc: add battery-low-hw-alarm property Flavio Suligoi
2019-04-03 14:52 ` [PATCH 2/2] rtc: pcf2127: add battery-low INTn generation Flavio Suligoi
2019-04-03 15:08 ` Alexandre Belloni
2019-04-03 15:14 ` Flavio Suligoi
2019-04-03 15:31 ` Alexandre Belloni
2019-04-03 15:49 ` Flavio Suligoi
2019-04-03 15:56 ` Alexandre Belloni
2019-04-03 16:09 ` Flavio Suligoi
2019-04-03 16:15 ` Alexandre Belloni [this message]
2019-04-03 16:20 ` Flavio Suligoi
2019-04-03 14:57 ` [PATCH 1/2] dt-bindings: rtc: add battery-low-hw-alarm property Alexandre Belloni
2019-04-03 15:06 ` Flavio Suligoi
2019-04-03 15:28 ` Alexandre Belloni
2019-04-03 15:32 ` Flavio Suligoi
2019-04-06 6:07 ` Rob Herring
2019-04-06 12:55 ` Alexandre Belloni
2019-04-08 7:22 ` Flavio Suligoi
2019-04-09 1:18 ` Rob Herring
2019-04-10 8:04 ` Flavio Suligoi
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