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Date:   Mon, 27 Apr 2020 09:51:49 +0100
From:   Lee Jones <lee.jones@linaro.org>
To:     saravanan sekar <sravanhome@gmail.com>
Cc:     andy.shevchenko@gmail.com, robh+dt@kernel.org, jic23@kernel.org,
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        sre@kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
        linux-pm@vger.kernel.org
Subject: Re: [PATCH v9 2/6] mfd: mp2629: Add support for mps battery charger
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On Fri, 24 Apr 2020, saravanan sekar wrote:

> 
> On 24/04/20 12:53 pm, Lee Jones wrote:
> > On Fri, 24 Apr 2020, saravanan sekar wrote:
> > 
> > > Hi Lee,
> > > 
> > > On 24/04/20 11:37 am, Lee Jones wrote:
> > > > On Fri, 24 Apr 2020, saravanan sekar wrote:
> > > > 
> > > > > Hi Lee,
> > > > > 
> > > > > On 24/04/20 9:18 am, Lee Jones wrote:
> > > > > > On Wed, 15 Apr 2020, Saravanan Sekar wrote:
> > > > > > 
> > > > > > > mp2629 is a highly-integrated switching-mode battery charge management
> > > > > > > device for single-cell Li-ion or Li-polymer battery.
> > > > > > > 
> > > > > > > Add MFD core enables chip access for ADC driver for battery readings,
> > > > > > > and a power supply battery-charger driver
> > > > > > > 
> > > > > > > Signed-off-by: Saravanan Sekar <sravanhome@gmail.com>
> > > > > > > ---
> > > > > > >     drivers/mfd/Kconfig        |  9 ++++
> > > > > > >     drivers/mfd/Makefile       |  2 +
> > > > > > >     drivers/mfd/mp2629.c       | 86 ++++++++++++++++++++++++++++++++++++++
> > > > > > >     include/linux/mfd/mp2629.h | 19 +++++++++
> > > > > > >     4 files changed, 116 insertions(+)
> > > > > > >     create mode 100644 drivers/mfd/mp2629.c
> > > > > > >     create mode 100644 include/linux/mfd/mp2629.h
> > > > > > How is this driver registered?
> > > > > > 
> > > > > > Looks like it has device tree support.  Is there another way?
> > > > > Yes, only using device tree
> > > > Then how about using 'simple-mfd' and 'syscon'?
> > > > 
> > > > Then you can omit this driver completely.
> > > The exception is to support for non device tree platform as well, but I have
> > > tested only for ARM device tree platform.
> > Is that a reality though?
> > 
> > How else do you see this realistically being registered?
> > 
> I understand that acpi related device table are not covered here, well I
> don't have to platform to test so.
> If you ask me to cover acpi related table, I can do but hard to test.

I don't know of any reasons why syscon can't be used by ACPI.

Please try to solve this issue using 'simple-mfd' and 'syscon'.

> > > > > > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > > > > > index 3c547ed575e6..85be799795aa 100644
> > > > > > > --- a/drivers/mfd/Kconfig
> > > > > > > +++ b/drivers/mfd/Kconfig
> > > > > > > @@ -434,6 +434,15 @@ config MFD_MC13XXX_I2C
> > > > > > >     	help
> > > > > > >     	  Select this if your MC13xxx is connected via an I2C bus.
> > > > > > > +config MFD_MP2629
> > > > > > > +	tristate "Monolithic power system MP2629 ADC and Battery charger"
> > > > > > > +	depends on I2C
> > > > > > > +	select REGMAP_I2C
> > > > > > > +	help
> > > > > > > +	  Select this option to enable support for monolithic power system
> > > > > > > +	  battery charger. This provides ADC, thermal, battery charger power
> > > > > > > +	  management functions on the systems.

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