Re: [PATCH v7 2/8] iio: core: add fixed point parsing with 64-bit parts

[Andy Shevchenko]

On Mon, Feb 23, 2026 at 12:37 PM Rodrigo Alencar
<455.rodrigo.alencar@xxxxxxxxx> wrote:
> On 26/02/23 11:06AM, Andy Shevchenko wrote:
> > On Sun, Feb 22, 2026 at 05:29:12PM +0000, Jonathan Cameron wrote:
> > > On Mon, 16 Feb 2026 15:02:17 +0000
> > > Rodrigo Alencar via B4 Relay <devnull+rodrigo.alencar.analog.com@xxxxxxxxxx> wrote:
> > >
> > > > Add iio_str_to_fixpoint64() function that leverages simple_strtoull()
> > > > to parse numbers from a string.
> > > > A helper function __iio_str_to_fixpoint64() replaces
> > > > __iio_str_to_fixpoint() implementation, extending its usage for
> > > > 64-bit fixed-point parsing.
> > > >
> > > > Signed-off-by: Rodrigo Alencar <rodrigo.alencar@xxxxxxxxxx>
> > > Hi Rodrigo.
> > >
> > > This looks fine to me, but given earlier discussions I'd ideally like
> > > to wait for a final review from Andy.
> >
> > It all depends on the series from Dmitry Antipov.
> > Can somebody help reviewing the patch 1 there?
> > https://lore.kernel.org/linux-hardening/20260212125628.739276-1-dmantipov@xxxxxxxxx/
>
> can we push for the exposure of that function to kernel modules?
> We have discussed that in v6, and I understand that:
>
> EXPORT_SYMBOL_FOR_MODULES(_parse_integer_limit, "industrialio");
> in lib/kstrtox.c;
>
> #include "../../lib/kstrtox.h"
> in drivers/iio/industrialio-core.c
>
> is not a good call...

Yep, because it's a temporary band-aid. The proper solution is to have
shared code provided by the lib/. So, the wrapper to parse 64-bit out
from the constant string literal should be part of the lib/ in the
result.

> > When it's in, we can continue on this one. TL;DR: for me this is on hold.
> > But if you see the need to have the driver being in IIO, please add a big
> > fat FIXME to make sure we will get this all being sorted out in the
> > (nearest?) future.
>
> I could add the FIXME into iio_safe_strntou64() doc header. It explains
> the context:
>
> > + * The implementation of this function is similar to _parse_integer_limit()
> > + * available in lib/kstrtox.h, but that header/function is not available to be
> > + * used in kernel modules. Hence, this implementation may need to change or
> > + * removed to reuse a new suitable helper that is properly exposed.

Up to Jonathan, I hope we can move the above mentioned series forward.
Without that, as I pointed out, this one sounds to me suboptimal and
unneeded double effort.


-- 
With Best Regards,
Andy Shevchenko