linux-kernel - Re: [PATCH] iio: tsl2772: Use device-managed API

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Message-ID: <20190729080307.GA360@onstation.org>
Date:   Mon, 29 Jul 2019 04:03:07 -0400
From:   Brian Masney <masneyb@...tation.org>
To:     Chuhong Yuan <hslester96@...il.com>
Cc:     Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: tsl2772: Use device-managed API

On Mon, Jul 29, 2019 at 11:03:00AM +0800, Chuhong Yuan wrote:
> Brian Masney <masneyb@...tation.org> 于2019年7月28日周日 下午4:31写道：
> > devm_add_action() could be used in the probe function to schedule the call
> > to tsl2772_chip_off(). That would eliminate the need for
> > tsl2772_remove(). See tsl2772_disable_regulators_action() for an example in
> > that driver.
> >
> 
> I find that we can use devm_add_action_or_reset() for
> tsl2772_disable_regulators_action() to eliminate the fault handling code.
> 
> I am not sure whether devm_add_action() can be used for
> tsl2772_chip_off() because it returns an integer, not void.
> And the return value is used in several functions.

I would add a wrapper function (tsl2772_chip_off_action?) with the
expected declaration that calls tsl2772_chip_off().

> > Chuhong: Another potential cleanup to shrink the size of this driver is
> > to move it over to the regulator_bulk_() API. I didn't realize that API
> > existed at the time I introduced the regulator support. If you're
> > interested in taking on that cleanup as well, I can test those changes
> > for you if you don't have the hardware.
> >
> > Brian
> >
> 
> Does that mean merging vdd_supply and vddio_supply to an array of
> regulator_bulk_data and utilize regulator_bulk_() API to operate them
> together?

Yes.

> I have an additional question that I find regulator_disable() is used in the
> end of many .remove functions of drivers, which hinders us to use devm
> functions.
> One example is drivers/iio/light/gp2ap020a00f.c.
> Is there any solution to this problem?

There are devm_regulator_*() variants of the regulator API available
that you can use. Lots of other APIs in the kernel have devm variants
to simply drivers.

Brian