linux-kernel - Re: [PATCH V2 2/2] power: twl4030_charger: attempt to power off in case of critical events

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Date:	Wed, 4 Jun 2014 08:01:42 -0500
From:	Nishanth Menon <nm@...com>
To:	Grazvydas Ignotas <notasas@...il.com>
CC:	<dbaryshkov@...il.com>, Tony Lindgren <tony@...mide.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Felipe Balbi <balbi@...com>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	<dwmw2@...radead.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V2 2/2] power: twl4030_charger: attempt to power off in
 case of critical events

On 06/04/2014 05:04 AM, Grazvydas Ignotas wrote:
> On Thu, May 29, 2014 at 12:46 AM, Nishanth Menon <nm@...com> wrote:
>> Attempt to power off in case of critical events such as battery removal,
>> over voltage events.
>>
>> There is no guarentee that we'd be in a safe scenario here, but the very
>> least we can try to do is to power off the device to prevent damage to
>> the system instead of just printing a message and hoping for the best.
> 
> At least "battery temperature out of range" does seem to happen quite
> often while charging on hot summer day. I'd prefer my pandora to not
> shutdown in such case, it could just stop charging instead.
Yeah, We could call
  twl4030_charger_enable_ac(false);
  twl4030_charger_enable_usb(bci, false);

But then, is that sufficient?
>From the TRM:
7.5.8 Battery Temperature Out-of-Range Detection
Battery temperature out-of-range detection detects whether the battery
temperature is within a specific
range. Detection is possible for two temperature ranges. When the
battery temperature is not in the
2–50°C range or is in the 3–43°C range, the TBATOR1 and TBATOR2 status
bits rise and an interrupt is
generated.
This MADC monitoring function can be enabled by writing to the
TBATOR1EN (BCIMFEN2[3]) and
TBATOR2EN (BCIMFEN2[1]) fields.

Battery pack at high temperature is a risk, no? and it may not be just
charger that might be causing such a condition. Is'nt it safer to shut
the device down in such a case?

-- 
Regards,
Nishanth Menon
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