##porting rk616 Audio codec driver from 3.0 version kernel to 4.0 version kernel:
- error: 'snd_soc_info_volsw_2r' undeclared here (not in a function)
- error: 'struct snd_soc_codec' has no member named 'mutex'
- error: 'struct snd_soc_dapm_widget' has no member named 'codec'
- error: 'struct snd_soc_codec' has no member named 'hw_read'
- error: 'struct snd_soc_codec' has no member named 'read'
- error: 'struct snd_soc_codec' has no member named 'write'