u_audio_set_playback_srate
u_audio_set_playback_srate(agdev, uac1->p_srate);
u_audio_set_playback_srate(agdev, val);
EXPORT_SYMBOL_GPL(u_audio_set_playback_srate);
int u_audio_set_playback_srate(struct g_audio *audio_dev, int srate);