linux-kernel - Re: [PATCH] power: twl4030_charger: clear IRQs after handling them

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Message-ID: <536CCC69.4000507@ti.com>
Date:	Fri, 9 May 2014 07:39:05 -0500
From:	Nishanth Menon <nm@...com>
To:	Tony Lindgren <tony@...mide.com>
CC:	Felipe Balbi <balbi@...com>, Russell King <linux@....linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	<dbaryshkov@...il.com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	<dwmw2@...radead.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] power: twl4030_charger: clear IRQs after handling them

On 05/08/2014 08:03 PM, Tony Lindgren wrote:
> * Nishanth Menon <nm@...com> [140506 17:25]:
>> Subject: [PATCH] power: twl4030_charger: detect battery presence prior to
>>  enabling charger
>>
>> TWL4030's Battery Charger seems to be designed for non-hotpluggable
>> batteries.
>>
>> If battery is not present in the system, BATSTS is always set with the
>> expectation that software will take actions to move to a required safe
>> state (could be power down or disable various charger paths).
>>
>> It does not seem possible even by manipulating the edge detection
>> of the event (using BCIEDR2 register) to have a consistent hotplug
>> handling. This seems to be the result of BATSTS interrupt generated
>> when the thermistor of the battery pack is disconnected from the
>> dedicated ADIN1 pin. Clearing the status just results in the status
>> being regenerated by the monitoring ADC(MADC) and disabling the
>> edges of event just makes hotplug no longer function. The only
>> other option is to disable the detection of the MADC by disabling
>> BCIMFEN4::BATSTSMCHGEN (battery presence detector) - but then, we can
>> never again detect battery reconnection.
>>
>> So, detect battery presence based on precharge(which is hardware
>> automatic state) or default main charger configuration at the time of
>> probe and enable charger logic only if battery was present.
>>
>> Reported-by: Russell King <linux@....linux.org.uk>
>> Signed-off-by: Nishanth Menon <nm@...com>
> 
> Gets rid of the errors for me if CONFIG_CHARGER_TWL4030=y.
> Looks like we don't have that enabled by default in
> omap2plus_defconfig which explain why it's taken so long to
> notice this one:
> 
> Tested-by: Tony Lindgren <tony@...mide.com>
> 
Thanks. I will post this out to the list as formal series.

-- 
Regards,
Nishanth Menon
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