On Mon, Jun 20, 2022 at 10:08 PM Aidan MacDonald <aidanmacdonald.0x0@xxxxxxxxx> wrote: > > No drivers currently use mask_writeonly, and in its current form > it seems a bit misleading. When set, mask registers will be > updated with regmap_write_bits() instead of regmap_update_bits(), > but regmap_write_bits() still does a read-modify-write under the > hood. It's not a write-only operation. > > Performing a simple regmap_write() is probably more useful, since > it can be used for chips that have separate set & clear registers > for controlling mask bits. Such registers are normally volatile > and read as 0, so avoiding a register read minimizes bus traffic. Reading your explanations and the code, I would rather think about fixing the regmap_write_bits() to be writeonly op. Otherwise it's unclear what's the difference between regmap_write_bits() vs. regmap_update_bits(). ... > if (d->chip->mask_writeonly) > - return regmap_write_bits(d->map, reg, mask, val); > + return regmap_write(d->map, reg, val & mask); > else > return regmap_update_bits(d->map, reg, mask, val); -- With Best Regards, Andy Shevchenko
