linux-kernel - Re: Motorola Droid 4 -- Stopping charger when battery is full

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Date:   Thu, 13 Apr 2023 11:34:13 +0200
From:   Pavel Machek <pavel@....cz>
To:     Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
Cc:     kernel list <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-omap@...r.kernel.org, tony@...mide.com, sre@...nel.org,
        nekit1000@...il.com, mpartap@....net, merlijn@...zup.org,
        martin_rysavy@...trum.cz, phone-devel@...r.kernel.org,
        maemo-leste@...ts.dyne.org
Subject: Re: Motorola Droid 4 -- Stopping charger when battery is full

Hi!

> > I complained that "battery life is very poor" with leste. It seems to
> > be combination of several factors.
> > 
> > 1) I was using very old battery
> > 
> > 2) My charger is detected as "USB", not as "AC"
> > 
> 
> And this is because there is no working charger detection in the driver, so
> initial current limit is hard-coded to 500mA.

Aha, thanks, makes sense.

> > According to my measurements "CPCAP_REG_CRM_FET_OVRD |
> > CPCAP_REG_CRM_FET_CTRL" results in battery discharding and 0A drawn
> > frmo the USB.  "CPCAP_REG_CRM_FET_OVRD" is phone powered from USB,
> > with battery more or less disconnected (<12mA), which is what we want
> > in battery full situation.
> > 
> 
> What will happen if phone needs to draw more than N mA (N is the set charger
> current limit)?

We may run over the limit, AFAICT. I guess one solution would be to
only do this when limit is high enough...

With current setup, phone will not boot if battery is empty, so this
needs quite urgent solution.

I updated my leste, and now have:

user@...uan-droid4:~/g/droid4-linux$ uname -a
Linux devuan-droid4 6.1.9 #1 SMP PREEMPT Mon Mar 20 15:16:53 UTC 2023 armv7l GNU/Linux
user@...uan-droid4:~/g$ apt show linux-image-omap
Package: linux-image-omap
Version: 6.1.8.0-1+m7

Where can I find corresponding sources?

Best regards,
							Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.

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