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Date: Mon, 5 May 2025 17:14:06 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andy@kernel.org>
Cc: David Lechner <dlechner@baylibre.com>, Marcelo Schmitt
 <marcelo.schmitt@analog.com>, linux-iio@vger.kernel.org,
 linux-kernel@vger.kernel.org, lars@metafoo.de,
 Michael.Hennerich@analog.com, nuno.sa@analog.com,
 marcelo.schmitt1@gmail.com
Subject: Re: [PATCH] iio: adc: ad4000: Avoid potential double data word read
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On Wed, 16 Apr 2025 09:47:03 +0300
Andy Shevchenko <andy@kernel.org> wrote:

> On Wed, Apr 16, 2025 at 09:01:02AM +0300, Andy Shevchenko wrote:
> > On Wed, Apr 16, 2025 at 8:59=E2=80=AFAM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote: =20
> > > On Wed, Apr 16, 2025 at 12:22=E2=80=AFAM David Lechner <dlechner@bayl=
ibre.com> wrote: =20
> > > > On 4/15/25 1:02 PM, Andy Shevchenko wrote: =20
>=20
> ...
>=20
> > > > It would have to be:
> > > >
> > > >         xfers[1].len =3D roundup_pow_of_two(BITS_TO_BYTES(chan->sca=
n_type.realbits));
> > > >
> > > > But that gets too long for 1 line =20
> > >
> > > Actually there are a handful of drivers including SPI core that need
> > > that helper already, I would prefer to have a helper defined in spi.h.
> > >
> > > , so I prefer what Marcelo wrote. =20
> > > >
> > > > Maybe an idea for another day:
> > > >
> > > > #define SPI_LEN_FOR_BITS(bits) roundup_pow_of_two(BITS_TO_BYTES(bit=
s)) =20
> > >
> > > Right, but as static inline to have stricter types.
> > > =20
> > > > There are a couple of places in spi/ that could use this and several
> > > > iio drivers. =20
> >=20
> > Or even wider, in bitops.h / bit*.h somewhere. Let me craft a patch. =20
>=20
> Just sent a mini-series, you are in Cc there.
>=20

I've picked this one up for now.  Assuming we'll cycle round to use the new
helper once it's available in my upstream.

Thanks,

Jonathan