linux-kernel - Re: [PATCH v14 07/10] mfd: simple-mfd-i2c: Add MAX77705 support

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Message-ID: <CABTCjFArONRgDBjiDABHfRhp1OQnZRFoirx4gNAR=wB4VPBZvg@mail.gmail.com>
Date: Mon, 13 Jan 2025 16:35:53 +0300
From: Dzmitry Sankouski <dsankouski@...il.com>
To: Lee Jones <lee@...nel.org>
Cc: Sebastian Reichel <sre@...nel.org>, Chanwoo Choi <cw00.choi@...sung.com>, 
	Krzysztof Kozlowski <krzk@...nel.org>, Rob Herring <robh@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Dmitry Torokhov <dmitry.torokhov@...il.com>, Pavel Machek <pavel@....cz>, 
	Hans de Goede <hdegoede@...hat.com>, Marek Szyprowski <m.szyprowski@...sung.com>, 
	Sebastian Krzyszkowiak <sebastian.krzyszkowiak@...i.sm>, Purism Kernel Team <kernel@...i.sm>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-input@...r.kernel.org, 
	linux-leds@...r.kernel.org
Subject: Re: [PATCH v14 07/10] mfd: simple-mfd-i2c: Add MAX77705 support

чт, 9 янв. 2025 г. в 15:53, Dzmitry Sankouski <dsankouski@...il.com>:
>
> чт, 9 янв. 2025 г. в 15:03, Lee Jones <lee@...nel.org>:
> >
> > On Thu, 09 Jan 2025, Lee Jones wrote:
> >
> > > On Wed, 08 Jan 2025, Dzmitry Sankouski wrote:
> > >
> > > > Add MAX77705 support - fuel gauge and hwmon devices.
> > > > Hwmon provides charger input and system bus measurements.
> > > >
> > > > Signed-off-by: Dzmitry Sankouski <dsankouski@...il.com>
> > > > ---
> > > > Changes in v13:
> > > > - remove compatible from cells
> > > > - change mfd compatible to match max77705 fuel gauge node
> > > > ---
> > > >  drivers/mfd/simple-mfd-i2c.c | 11 +++++++++++
> > > >  1 file changed, 11 insertions(+)
> > > >
> > > > diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> > > > index 6eda79533208..22159913bea0 100644
> > > > --- a/drivers/mfd/simple-mfd-i2c.c
> > > > +++ b/drivers/mfd/simple-mfd-i2c.c
> > > > @@ -83,11 +83,22 @@ static const struct simple_mfd_data maxim_max5970 = {
> > > >     .mfd_cell_size = ARRAY_SIZE(max5970_cells),
> > > >  };
> > > >
> > > > +static const struct mfd_cell max77705_sensor_cells[] = {
> > > > +   { .name = "max77705-battery" },
> > > > +   { .name = "max77705-hwmon", },
> > > > +};
> >
> > Why not register these from the proper MFD driver?
> >
>
> Because the fuel gauge address is different from the max77705 mfd device.

In more details:

we had a discussion with Krzysztof about fuel gauge device
[1], [2], [3] and agreed that it should be modeled as a separate device,
because it has no common resources with max77705 device, and has separate
address. This means its node are out of MAX77705 mfd node, forming its own
MFD with shared i2c bus.

https://lore.kernel.org/lkml/55f32164-f504-4409-8ce2-6462b833da89@kernel.org/
https://patchwork.kernel.org/project/linux-input/patch/20241202-starqltechn_integration_upstream-v9-3-a1adc3bae2b8@gmail.com/
https://patches.linaro.org/project/linux-leds/patch/20241217-starqltechn_integration_upstream-v12-2-ed840944f948@gmail.com/#951752

-- 
Best regards and thanks for review,
Dzmitry