Well I don't have any preference (read enough knowledge) either here and I hardly think performance becomes issue in any configuration.
So my next question, is the change to dw_reg_write something that I should
write and submit, or should someone else submit something more generalized,
like option 2 above? I don't own the i2c driver, I'm just trying to fix one
issue on one processor with minimal risk of breaking something. I don't have
the broader view of what's optimal for the whole DesignWare i2c driver. I
also don't have any way to test changes on other models of processors.
Well, I guess this is a question for the designware maintainers: do we
want this one conversion from *_relaxed to non-relaxed. Or are we
playing safe by using non-relaxed all the time. I would suggest the
latter because the drivers I look after hardly write registers in a hot
path (and not many of them at a time). But you guys know your driver
better...