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Date:   Tue, 12 Feb 2019 08:04:57 +0000
From:   Lee Jones <lee.jones@linaro.org>
To:     Mark Zhang <markz@nvidia.com>
Cc:     blaws05@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org
Subject: Re: [PATCH v2 0/4] Add max77620 charging & low battery support
Message-ID: <20190212080457.GL20638@dell>
References: <20190129085531.32364-1-markz@nvidia.com>
 <20190207084836.GF4672@dell>
 <a43eb007-c984-a209-2b4e-6672807029aa@nvidia.com>
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On Tue, 12 Feb 2019, Mark Zhang wrote:

> On 2/7/2019 4:48 PM, Lee Jones wrote:
> > On Tue, 29 Jan 2019, Mark Zhang wrote:
> > 
> >> This patch set adds support for max77620 backup battery charging and
> >> low battery monitoring.
> >>
> >> Changes in v2:
> >> - Add devicetree binding documentation
> >>
> >> Mark Zhang (4):
> >>   mfd: max77620: Add backup battery charger support
> >>   mfd: max77620: add documentation for backup battery charging
> >>   mfd: max77620: Add low battery monitor support
> >>   mfd: max77620: add documentation for low battery monitoring
> >>
> >>  .../devicetree/bindings/mfd/max77620.txt      |  34 +++++
> >>  drivers/mfd/max77620.c                        | 137 +++++++++++++++++-
> > 
> > All of this needs moving out to the correct subsystem.
> > 
> > drivers/power/supply/max77620-battery.c looks right.
> 
> Actually max77620 is not a power supply device. This patch set adds 2
> features:
> - Backup battery charger. The RTC in max77620 is supplied from a backup
> battery and consumes 2.0uA when no other power sources are available. So
> basically this is not a system battery charger, it's just for RTC.
> - Low battery monitoring. This is for monitoring the system main battery
> voltage, so max77620 can shutdown or reset the SoC accordingly. But I
> think this doesn't conform the idea of "power supply" driver as well.

Most other battery handling seems to happen in
drivers/power/supply/*.battery*.  If that's not the right location,
then you need to find a place for it to go.  MFDs do not provide
useful functionality per say - that is the role of the child devices.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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