linux-kernel - Re: [PATCH] power: supply: bq256xx: Remove init ichg/vbat with max value

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Message-ID: <20221203010303.it5urfo2i7pj4n3n@mercury.elektranox.org>
Date:   Sat, 3 Dec 2022 02:03:03 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Hermes Zhang <Hermes.Zhang@...s.com>
Cc:     kernel <kernel@...s.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] power: supply: bq256xx: Remove init ichg/vbat with max
 value

Hi,

On Wed, Nov 30, 2022 at 09:27:42AM +0000, Hermes Zhang wrote:
> Hi,
> 
> 在 2022/11/29 23:27, Sebastian Reichel 写道:
> > Hi,
> >
> > On Tue, Nov 29, 2022 at 05:01:12PM +0800, Hermes Zhang wrote:
> >> Init the ichg and vbat reg with max value is not good. First the chip
> >> already has a default value for ichg and vbat (small value). Init these
> >> two reg with max value will result an unsafe case (e.g. battery is over
> >> charging in a hot environment) if no user space change them later.
> >>
> >> Signed-off-by: Hermes Zhang <chenhuiz@...s.com>
> >> ---
> > It's the driver's task to setup safe initial maximum values.
> > Pre-kernel values may or may not be safe if you consider things
> > like kexec. If you get unsafe values programmed, then fix the
> > values instead.
> >
> > -- Sebastian
> 
> The constant_charge_current_max_ua is either from dts or default value 
> for each chip in the code, but I guess I could ot change them because it 
> has their own meaning (it will be used to check if the setting is valid 
> or not). Do you mean I can set some other value here instead of 
> constant_xxx_max?

You can just change the DT value to something safe as it is meant to be?

-- Sebastian

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