> > +	/* flush TX/RX FIFOs */
> > +	val = (BIT(S_FIFO_RX_FLUSH_SHIFT) | BIT(S_FIFO_TX_FLUSH_SHIFT));
> > +	writel(val, iproc_i2c->base + S_FIFO_CTRL_OFFSET);
> 
> Will flushing FIFOs work when a slave is register while a master
> transfer is on-going at the same time?

Sorry, my bad, this can't happen. Registering a slave is protected by
the adapter lock.