Re: [PATCH v4 3/7] iio: frequency: adf41513: driver implementation

Rodrigo Alencar
2026-01-20T13:07:59Z

On 26/01/20 01:24PM, Andy Shevchenko wrote:
> On Tue, Jan 20, 2026 at 12:43 PM Rodrigo Alencar
> <455.rodrigo.alencar@gmail.com> wrote:
> > On 26/01/19 07:07PM, Andy Shevchenko wrote:
> > > On Mon, Jan 19, 2026 at 04:37:09PM +0000, Rodrigo Alencar wrote:
> > > > On 26/01/19 03:42PM, Andy Shevchenko wrote:
> > > > > On Mon, Jan 19, 2026 at 11:21:59AM +0000, Rodrigo Alencar wrote:
> > > > > > On 26/01/19 09:31AM, Andy Shevchenko wrote:
> > > > > > > On Fri, Jan 16, 2026 at 02:32:22PM +0000, Rodrigo Alencar via B4 Relay wrote:

...

> > > > > > The current implementation is kind of a stripped version of
> > > > > > __iio_str_to_fixpoint(). Would you prefer something like this, then?:
> > > > >
> > > > > Do they have most of the parts in common? If so, why can't we use
> > > > > __iio_str_to_fixpoint() directly? Or why can't we slightly refactor
> > > > > that to give us the results we need here?
> > > >
> > > > __iio_str_to_fixpoint() only parses "int" chunks, adf41513_parse_uhz
> > > > was modified to accomodate the u64 parsing removing unnecessary stuff.
> > >
> > > But why? The fractional part most likely will be kept int (it's up to 10⁻⁹).
> > > The integer can be bigger than 10⁹?
> > >
> >
> > Correct, integer part of the frequency value goes up to 26.5 GHz
> > (uint_max is approx 4.3 GHz). Also, with the dual modulus, the PLL can
> > achieve micro Hz resolution.
>
> µHz is not a problem since it's up to nHz.
> So, the difference so far is the integer part that can be 64-bit.
> Again, can we factor out something to be used for this and for the
> __iio_str_to_fixpoint() cases?

I am not sure what you are suggesting, but I am avoiding changes to
iio core at this point. If any other user needs similar behavior,
I'd say we would need to have __iio_str_to_fixpoint() implementation
modified, so to create a version of iio_str_to_fixpoint() that handles
long long variables. Possibly consuming simple_strtoull instead of
doing the manual parsing.

Kind regards,

Rodrigo Alencar