[alsa-devel] ASOC: For SND_SOC_DAIFMT_IB_IF what is invert baseed on?

[Richard Zhao]

Hi,

include/sound/soc.h
/*
 * DAI hardware signal inversions
 */
#define SND_SOC_DAIFMT_NB_NF            (0 << 8)        /* normal bclk + frm */
#define SND_SOC_DAIFMT_NB_IF            (1 << 8)        /* normal bclk
+ inv frm */
#define SND_SOC_DAIFMT_IB_NF            (2 << 8)        /* invert bclk
+ nor frm */
#define SND_SOC_DAIFMT_IB_IF            (3 << 8)        /* invert bclk + frm */

What are frame cock and bit clock invert based on? I2S, PCM or some
else bus protocols? Or just high level voltage or low level voltage?

Thanks
Richard