[PATCH 01/20] bitfield: introduce HWORD_UPDATE bitfield macros

[Yury Norov]

On Thu, Jun 12, 2025 at 09:50:12PM +0200, Nicolas Frattaroli wrote:
> On Thursday, 12 June 2025 21:44:15 Central European Summer Time Jakub Kicinski wrote:
> > On Thu, 12 Jun 2025 20:56:03 +0200 Nicolas Frattaroli wrote:
> > > Hardware of various vendors, but very notably Rockchip, often uses
> > > 32-bit registers where the upper 16-bit half of the register is a
> > > write-enable mask for the lower half.
> > 
> > Please limit the spread of this weirdness to a rockchip or "hiword"
> > specific header. To a normal reader of bitfield.h these macros will
> > be equally confusing and useless.
> > 
> 
> That is how this change started out, and then a different maintainer told
> me that this is a commonly used thing (see: the sunplus patch), and
> Rockchip just happens to have a lot of these with consistent naming.

That other maintainer was me, and the macro is indeed not used by rockchip
weirdness solely:

$ git grep HIWORD | grep -v rockchip | wc -l
326

I don't think that that having HWORD_UPDATE() in bitfield.h is a wrong
thing. Jakub, if you do, we can just create a new header for it.

Thanks,
Yury