Why is there no SND_SOC_DAIFMT_TDM bit?

Hi,

I wonder why there is no SND_SOC_DAIFMT_TDM format although there actual codecs supporting TDM.

Most of the drivers I see use SND_SOC_DAIFMT_DSP_A or SND_SOC_DAIFMT_DSP_B to signal that the format used is TDM.