Re: [PATCH 03/22] iio: adc: add support for X-Powers AXP20X and AXP22X PMICs ADCs

From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Quentin Schulz <quentin.schulz@free-electrons.com>
Cc: "Chen-Yu Tsai" <wens@csie.org>,
	"Jonathan Cameron" <jic23@kernel.org>,
	knaack.h@gmx.de, "Lars-Peter Clausen" <lars@metafoo.de>,
	"Peter Meerwald-Stadler" <pmeerw@pmeerw.net>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Sebastian Reichel" <sre@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Lee Jones" <lee.jones@linaro.org>,
	linux-iio@vger.kernel.org,
	devicetree <devicetree@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"open list:THERMAL" <linux-pm@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	"Thomas Petazzoni" <thomas.petazzoni@free-electrons.com>,
	"Icenowy Zheng" <icenowy@aosc.xyz>,
	"Bruno Prémont" <bonbons@linux-vserver.org>
Subject: Re: [PATCH 03/22] iio: adc: add support for X-Powers AXP20X and AXP22X PMICs ADCs
Date: Thu, 5 Jan 2017 17:46:51 +0100	[thread overview]
Message-ID: <20170105164651.tk5e3rhdthtpn4lc@lukather> (raw)
In-Reply-To: <cf4590d1-5381-f1da-7271-e6e7fee0c479@free-electrons.com>

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On Thu, Jan 05, 2017 at 10:50:33AM +0100, Quentin Schulz wrote:
> >>>> +static int axp20x_remove(struct platform_device *pdev)
> >>>> +{
> >>>> +       struct axp20x_adc_iio *info;
> >>>> +       struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> >>>> +
> >>>> +       info = iio_priv(indio_dev);
> >>>
> >>> Nit: you could just reverse the 2 declarations above and join this
> >>> line after struct axp20x_adc_iio *info;
> >>>
> >>>> +       regmap_write(info->regmap, AXP20X_ADC_EN1, 0);
> >>>> +       regmap_write(info->regmap, AXP20X_ADC_EN2, 0);
> >>>
> >>> The existing VBUS power supply driver enables the VBUS ADC bits itself,
> >>> and does not check them later on. This means if one were to remove this
> >>> axp20x-adc module, the voltage/current readings in the VBUS power supply
> >>> would be invalid. Some sort of workaround would be needed here in this
> >>> driver of the VBUS driver.
> >>>
> >>
> >> That would be one reason to migrate the VBUS driver to use the IIO
> >> channels, wouldn't it?
> > 
> > It is, preferably without changing the device tree.
> > 
> 
> Yes, of course.

Note that you can have something like a test for the iio channel
property in the VBUS driver, and keep the old behaviour in the case
where we wouldn't have it.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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