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References: <20240425-b4-iio-masklength-cleanup-v1-0-d3d16318274d@baylibre.com>
 <2630ef8c8363b4fa772a2ff2c95cf115ad3c509d.camel@gmail.com>
In-Reply-To: <2630ef8c8363b4fa772a2ff2c95cf115ad3c509d.camel@gmail.com>
From: David Lechner <dlechner@baylibre.com>
Date: Fri, 26 Apr 2024 10:26:31 -0500
Message-ID: <CAMknhBGQB4MC8ejEs_uLgb=iKehXkoetgHjZnCvCKQbuua5kfA@mail.gmail.com>
Subject: Re: [PATCH 0/3] iio: cleanup masklength usage
To: =?UTF-8?B?TnVubyBTw6E=?= <noname.nuno@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>, Lars-Peter Clausen <lars@metafoo.de>, 
	Michael Hennerich <Michael.Hennerich@analog.com>, Shawn Guo <shawnguo@kernel.org>, 
	Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix Kernel Team <kernel@pengutronix.de>, 
	Fabio Estevam <festevam@gmail.com>, linux-iio@vger.kernel.org, 
	linux-kernel@vger.kernel.org, imx@lists.linux.dev, 
	linux-arm-kernel@lists.infradead.org
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On Fri, Apr 26, 2024 at 2:13=E2=80=AFAM Nuno S=C3=A1 <noname.nuno@gmail.com=
> wrote:
>
> On Thu, 2024-04-25 at 10:03 -0500, David Lechner wrote:
> > While working on other patches I noticed that a few drivers are setting
> > the masklength field of struct iio_dev even though it is marked as
> > [INTERN]. It looks like maybe this was not always the case, but we can
> > safely clean it up now without breaking anything.
> >
> > ---
> > David Lechner (3):
> >       iio: adc: ad7266: don't set masklength
> >       iio: adc: mxs-lradc-adc: don't set masklength
> >       iio: buffer: initialize masklength accumulator to 0
> >
> >  drivers/iio/adc/ad7266.c          | 1 -
> >  drivers/iio/adc/mxs-lradc-adc.c   | 1 -
> >  drivers/iio/industrialio-buffer.c | 2 +-
> >  3 files changed, 1 insertion(+), 3 deletions(-)
> > ---
> > base-commit: b80ad8e3cd2712b78b98804d1f59199680d8ed91
> > change-id: 20240425-b4-iio-masklength-cleanup-86b632b19901
> >
>
> Hi David,
>
> Nice cleanup. The patches look good to me but there's one thing missing :=
). As you
> correctly noted, the field should be internal to the IIO core and drivers=
 should not
> touch it. Hence, you need to make sure not driver is using it so we can m=
ove it into
> struct iio_dev_opaque [1]. That's the place all the intern fields should,=
 eventually,
> end up.
>
> Now, quite some drivers in the trigger handler will read the masklength f=
or looping
> with for_each_set_bit(). Hence, the straight thing would be an helper to =
get it.
> Maybe there's a clever way...
>
> I know this is more work than what you had in mind but I think it should =
be fairly
> simple (hopefully) and since you started it :), maybe we can get the whol=
e thing done
> and remove another [INTERN] member from the iio_dev struct.
>
> [1]: https://elixir.bootlin.com/linux/latest/source/include/linux/iio/iio=
-opaque.h#L42
>
> - Nuno S=C3=A1

Sounds like fun. :-p

I will look into it.