Re: [PATCH 07/11] iio: adc: Add support for QCOM PMIC5 Gen3 ADC

From: Jonathan Cameron <jic23@kernel.org>
To: Jishnu Prakash <quic_jprakash@quicinc.com>
Cc: agross@kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linus.walleij@linaro.org,
	Jonathan.Cameron@huawei.com, sboyd@kernel.org,
	dmitry.baryshkov@linaro.org, quic_subbaram@quicinc.com,
	quic_collinsd@quicinc.com, quic_kamalw@quicinc.com,
	marijn.suijten@somainline.org, andriy.shevchenko@linux.intel.com,
	krzysztof.kozlowski@linaro.org,
	"Lars-Peter Clausen" <lars@metafoo.de>,
	"Bjorn Andersson" <andersson@kernel.org>,
	"Konrad Dybcio" <konrad.dybcio@linaro.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Cosmin Tanislav" <demonsingur@gmail.com>,
	"Mike Looijmans" <mike.looijmans@topic.nl>,
	"Ramona Bolboaca" <ramona.bolboaca@analog.com>,
	"ChiYuan Huang" <cy_huang@richtek.com>,
	"Ibrahim Tilki" <Ibrahim.Tilki@analog.com>,
	"William Breathitt Gray" <william.gray@linaro.org>,
	"Lee Jones" <lee@kernel.org>,
	"Leonard Göhrs" <l.goehrs@pengutronix.de>,
	"Haibo Chen" <haibo.chen@nxp.com>,
	linux-iio@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-msm-owner@vger.kernel.org
Subject: Re: [PATCH 07/11] iio: adc: Add support for QCOM PMIC5 Gen3 ADC
Date: Fri, 27 Oct 2023 14:26:18 +0100	[thread overview]
Message-ID: <20231027142512.37358c60@jic23-huawei> (raw)
In-Reply-To: <13d5dee2-1da4-2ad0-91f8-a53b43adba2b@quicinc.com>

> > +  
> >> +static const struct iio_info adc5_gen3_info = {
> >> +	.read_raw = adc5_gen3_read_raw,
> >> +	.fwnode_xlate = adc5_gen3_fwnode_xlate,
> >> +};  
> > ...  
> 
> 
> Did you mean to leave any comment here...?

Nope ... is a cut mark to indicate I dropped a load of quoted text.

On that note, don't bother replying to say you'll do things suggested
by reviewers - we assume you will unless you say otherwise :)

If you want to add a boilerplate message alongside comments on the
bits that need further discussion, along the lines of 
"All other comments accepted." That's fine but it's not really necessary.

...

> >> +
> >> +static int adc5_gen3_exit(struct platform_device *pdev)
> >> +{  
> > As you are mixing devm manged cleanup and the explicit sort the
> > result is that you remove the userspace interfaces 'after' you run
> > everything in here. I'm thinking disabling the channels at least
> > isn't a good idea in that case.
> >
> > If you want to use devm (which is good) then you need to work out how
> > to register additional callbacks during probe to tear down everything in
> > the right order (typically the reverse of what happens in probe)
> > devm_add_action_or_reset() is the way to add those extra callbacks.
> >
> > If not, just don't use devm for at least those bits that will end up
> > running out of order (such as iio_device_register()) and manually call their
> > cleanup routines instead.  
> 
> 
> I checked some other examples in the iio/adc/ folder, I think I see what 
> you mean here. It looks like drivers with a remove callback always use 
> iio_device_register and iio_device_unregister instead of the devm_* 
> variant, due to the issue with sysfs removal as you said.
> 
> I'll update the probe and remove functions similarly, to do explicit 
> cleanups as required, avoiding devm_ usage for places where it should be 
> avoided.

Better to go the other way as Dmitry suggested.  Make everything you can
devm managed.