Re: [PATCH 07/12] iio: pressure: rohm-bm1390: Fix AVE_NUM initialization

[Jonathan Cameron]

On Tue, 11 Aug 2026 13:08:14 +0300
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:

> On Tue, Aug 11, 2026 at 12:05:47PM +0300, Matti Vaittinen wrote:
> > On 10/08/2026 23:06, Andy Shevchenko wrote:  
> > > On Mon, Aug 10, 2026 at 10:53:07AM +0300, Matti Vaittinen wrote:  
> 
> ...
> 
> > > > Use FIELD_PREP() to shift the intended AVE_NUM value to correct field.  
> > > 
> > > Can it be FIELD_PREP_CONST()?  
> > 
> > Can you please elaborate why it should in this case?  
> 
> I'm not sure why it's not obvious, but the parameters are constants, why would
> we need an additional check or even checks?
> 
I'm not sure it is as obvious as the name would suggest.
FIELD_PREP() has a whole bunch of stuff that runs if it happens
to have a build time constant value +  FIELD_PREP_CONST() is
documented as primarily being there when the code requires a constant
to be correct.  Whether FIELD_PREP() collapses to a constant in
a recent compiler is something I'm not sure of.

Jonathan