On Thu, Dec 9, 2021 at 9:26 AM Zev Weiss <zweiss@xxxxxxxxxxx> wrote: > On Wed, Dec 08, 2021 at 05:58:30AM PST, Jonathan Neuschäfer wrote: > >> BIT() > > > >I'll use it, but in this case, I think it doesn't simplify much the > >whole expression all that much. Is there perhaps a macro that > >constructs a continuous bitmask of N bits, perhaps additionally > >left-shifted by M bits? > > > >Maybe somewhere in the bitmap_* API... > > > > There's GENMASK(), though it takes a high bit and low bit rather than a > bit position and count, so it'd require a small bit of arithmetic, e.g. > > lastbit = gpio->first_irq_bit + gpio->num_irqs - 1; > ours = GENMASK(lastbit, gpio->first_irq_bit); > > or a manual shift: > > ours = GENMASK(gpio->num_irqs - 1, 0) << gpio->first_irq_bit; I think this can be handled with FIELD_PREP() from <linux/bitfield.h>? Some examples at the top of the header. Yours, Linus Walleij
