-----Original Message----- From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com] Sent: Monday, September 19, 2011 3:56 PM To: Ashish Jangam Subject: Re: LKML - Battery charge current issue

On Mon, Sep 19, 2011 at 06:26:10AM +0000, Ashish Jangam wrote:

Questions like this should always be CCed to the list.

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Some Power Management Controllers has a feature of configuring battery charge current for faster battery charging.

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In the Linux power supply core there is no provision that can help the user for configuring battery charge current at "runtime". In current Linux

implementation

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this is done in battery "probe" probably using platform data.

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Should an additional entry in sysfs be added for configuring battery charge

current

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since most of our clients desire such feature?

This depends what you're looking to do. The specific currents used should be configured using platform data, if the user gets these wrong they can result in physical damage to the system so it's generally undesirable to have userspace poking at them. The switch from trickle to fast charge is normally managed automatically, often by hardware. If there's absolutely no way to figure this out from kernel I guess a userspace control would be OK but it'd be pretty surprising.

Hardware that don't support/have automatic upgrade then, quick battery charge feature will be of no use to end user and especially in smart phone this could be problematic.

If sysfs is not a good way of doing this then some alternate mechanism will be very much appreciated.