linux-kernel - Re: [PATCH v2 5/8] power: supply: qcom_battmgr: Add charge control support

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Message-ID: <5knsdgk7o5zifkvzlrqiplmhztnsyhlxnqiuikqf4l7wkx2qvh@s3vzkiezw2bc>
Date: Tue, 3 Jun 2025 13:37:06 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Fenglin Wu <fenglin.wu@....qualcomm.com>
Cc: György Kurucz <me@...uczgy.com>,
        Sebastian Reichel <sre@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Subbaraman Narayanamurthy <subbaraman.narayanamurthy@....qualcomm.com>,
        David Collins <david.collins@....qualcomm.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, kernel@....qualcomm.com,
        devicetree@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v2 5/8] power: supply: qcom_battmgr: Add charge control
 support

On Tue, Jun 03, 2025 at 01:48:11PM +0800, Fenglin Wu wrote:
> 
> On 5/31/2025 6:36 PM, György Kurucz wrote:
> > > Add charge control support for SM8550 and X1E80100.
> > 
> > Thank you for this, tested on my Lenovo Yoga Slim 7x, the limiting works
> > well, I finally don't have to worry about leaving my laptop plugged in
> > for too long.
> > 
> > One small thing I noticed is that after setting the sysfs values and
> > rebooting, they report 0 again. The limiting appears to stay in effect
> > though, so it seems that the firmware does keep the values, but Linux
> > does not read them back. Indeed, looking at the code, it seems that
> > actually reading back the values is only implemented for the SM8550.
> 
> Right.
> 
> Based on offline information, X1E80100 doesn't support reading back those
> threshold values in battery management firmware, so I can only use the
> cached values for sysfs read.

Which limits usablity of the attribute, it is now impossible to identify
whether it is enabled or disabled. Is there a chance of fixing that for
the X1E80100 platform?

> 
> > 
> > Anyway, this is just a small nitpick, this does not really affect the
> > functionality, and I would support merging this series regardless of
> > whether the read back values are always correct.
> > 
> > György

-- 
With best wishes
Dmitry