Re: [PATCH v5 02/13] mfd: add simple regmap based I2C driver

From: Lee Jones <lee.jones@linaro.org>
To: Michael Walle <michael@walle.cc>
Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
	linux-pwm@vger.kernel.org, linux-watchdog@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Bartosz Golaszewski" <bgolaszewski@baylibre.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Jean Delvare" <jdelvare@suse.com>,
	"Guenter Roeck" <linux@roeck-us.net>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Wim Van Sebroeck" <wim@linux-watchdog.org>,
	"Shawn Guo" <shawnguo@kernel.org>, "Li Yang" <leoyang.li@nxp.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Jason Cooper" <jason@lakedaemon.net>,
	"Marc Zyngier" <maz@kernel.org>,
	"Mark Brown" <broonie@kernel.org>
Subject: Re: [PATCH v5 02/13] mfd: add simple regmap based I2C driver
Date: Mon, 20 Jul 2020 08:43:12 +0100	[thread overview]
Message-ID: <20200720074312.GL3165313@dell> (raw)
In-Reply-To: <52d85ea1ddc488762df547168e2001e9@walle.cc>

On Mon, 20 Jul 2020, Michael Walle wrote:

> Am 2020-07-17 11:06, schrieb Lee Jones:
> > On Mon, 06 Jul 2020, Michael Walle wrote:
> > 
> > > There are I2C devices which contain several different functions but
> > > doesn't require any special access functions. For these kind of
> > > drivers
> > > an I2C regmap should be enough.
> > > 
> > > Create an I2C driver which creates an I2C regmap and enumerates its
> > > children. If a device wants to use this as its MFD core driver, it has
> > > to add an individual compatible string. It may provide its own regmap
> > > configuration.
> > > 
> > > Subdevices can use dev_get_regmap() on the parent to get their regmap
> > > instance.
> > > 
> > > Signed-off-by: Michael Walle <michael@walle.cc>
> > > ---
> > > Changes since v4:
> > >  - new patch. Lee, please bear with me. I didn't want to delay the
> > >    new version (where a lot of remarks on the other patches were
> > >    addressed) even more, just because we haven't figured out how
> > >    to deal with the MFD part. So for now, I've included this one.
> > > 
> > >  drivers/mfd/Kconfig          |  9 +++++++
> > >  drivers/mfd/Makefile         |  1 +
> > >  drivers/mfd/simple-mfd-i2c.c | 50
> > > ++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 60 insertions(+)
> > >  create mode 100644 drivers/mfd/simple-mfd-i2c.c
> > > 
> > > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > > index 33df0837ab41..f1536a710aca 100644
> > > --- a/drivers/mfd/Kconfig
> > > +++ b/drivers/mfd/Kconfig
> > > @@ -1162,6 +1162,15 @@ config MFD_SI476X_CORE
> > >  	  To compile this driver as a module, choose M here: the
> > >  	  module will be called si476x-core.
> > > 
> > > +config MFD_SIMPLE_MFD_I2C
> > > +	tristate "Simple regmap based I2C devices"
> > 
> > Doesn't look like tristate to me.
> > 
> > Haven't you made this builtin only?
> 
> Mh yeah, I forgot to change it to module in the driver. I don't
> know whats better though, have it tristate or just offer a boolean
> option because it should be small anyway. What do you think?
> My interrupt driver will force it to boolean anyway.

Better to give consumers the choice I think.

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