If the Kinetis I2s the module could be connected as Slave Sierra Gsm module is master in pcm.
The waveforms are similar but not exactly the same for that question.
The Fs of kinetis is half clock cycle advance respect to the drawing of the Sierra.
In the file i2s ....... is the drawing that shows the Kinetis Slave mode and file Sierra_pcm this drawing that shows the Sierra.
Question: Is it possible to configure the I2S module of Kinetis for it to work in slave mode gsm module (pcm) Siera Wireless
Best regards