> I agree but I could not find a neat way of doing it. How about?
> 
>     bool use_4tap = host->pdata->flags & TMIO_MMC_HAVE_4TAP_HS400;
> 
>     if (!(host->mmc->ios.timing == MMC_TIMING_UHS_SDR104) &&
> 	!(host->mmc->ios.timing == MMC_TIMING_MMC_HS200) &&
> 	!(host->mmc->ios.timing == MMC_TIMING_MMC_HS400 && !use_4tap))
> 	   return false;

Yeah, it's not much but the best I could think of right now, too. But it
definately is better.