[alsa-devel] Question about SND_SOC_DAIFMT_xB_xF

[Lars-Peter Clausen]

On 07/31/2014 04:01 AM, Kuninori Morimoto wrote:
> r example, if some data format requests that data is sent from "rising edge",
> but HW send data from "falling edge" in default setting.
> This case, HW should use inverted edge.
> Then, should HW send it by SND_SOC_DAIFMT_NB_NF (= based on required format) ?
> or SND_SOC_DAIFMT_NB_IF (= based on default HW behavior) ?

The same set of settings passed to snd_soc_dai_set_fmt() must for all 
drivers result in the same waveforms. Otherwise interoperability is pretty 
hard to archive. This means the clock invert settings are always be relative 
to the selected DAI format (I2S, LJ, RJ, ...). The hardware default of the 
specific IP that the driver was written for does not matter in this case.