Hi, On Thu 07 Nov 19, 23:39, Russell King - ARM Linux admin wrote: > On Thu, Nov 07, 2019 at 09:46:45PM +0100, Rikard Falkeborn wrote: > > Arguments are supposed to be ordered high then low. > > > > Signed-off-by: Rikard Falkeborn <rikard.falkeborn@xxxxxxxxx> > > --- > > Spotted while trying to add compile time checks of GENMASK arguments. > > Patch has only been compile tested. > > My feeling, personally, is that GENMASK() really isn't worth the pain > it causes. Can we instead get rid of this thing and just use easier > to understand and less error-prone hex masks please? One advantage it has is that is matches the order in which bit fields are usually given in datasheets, so I personally found that it makes verification of fields much more straightforward and immediate. My 2 cents are that it makes sense for hardware registers. Note that I have recently introduced a SHIFT_AND_MASK_BITS macro[0] for a V4L2 driver, that I (and Mauro) would like to move to linux/bits.h eventually. > I don't care what anyone else says, personally I'm going to stick with > using hex masks as I find them way easier to get right first time than > a problematical opaque macro - and I really don't want the effort of > finding out that I've got the arguments wrong when I build it. It's > just _way_ easier and less error prone to use a hex mask straight off. I guess it's a matter of personal habit. [0]: https://git.linuxtv.org/media_tree.git/commit/?id=06eff2150d4db991ca236f3d05a9dc0101475aea Cheers, Paul -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com
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