-- fsl,mode: The operating mode for the SSI interface.
- "i2s-slave" - I2S mode, SSI is clock slave
- "i2s-master" - I2S mode, SSI is clock master
- "lj-slave" - left-justified mode, SSI is clock slave
- "lj-master" - l.j. mode, SSI is clock master
- "rj-slave" - right-justified mode, SSI is clock slave
- "rj-master" - r.j., SSI is clock master
- "ac97-slave" - AC97 mode, SSI is clock slave
- "ac97-master" - AC97 mode, SSI is clock master