Hi All I'm implementing a driver for TEF663x, and link (machine driver) to iMX6 (kernel 4.x) I understand ALSA and ASOC layers and architecture. I have good knowledge about both chipset (soc and codec). Nevertheless I am really confused with asoc structures, wich fields are mandatory and some links between platform, machine and codec. 1-Why teh followin controls are duplicated? When muste ia have to use each one? struct snd_soc_component_driver{ .... /* Default control and setup, added after probe() is run */ const struct snd_kcontrol_new *controls; unsigned int num_controls; const struct snd_soc_dapm_widget *dapm_widgets; unsigned int num_dapm_widgets; const struct snd_soc_dapm_route *dapm_routes; unsigned int num_dapm_routes; .... } but this struct is included in snd_soc_codec_driver, which one has his own widgets, routes and kcontrols struct snd_soc_codec_driver { ..... struct snd_soc_component_driver component_driver; /* Default control and setup, added after probe() is run */ const struct snd_kcontrol_new *controls; int num_controls; const struct snd_soc_dapm_widget *dapm_widgets; int num_dapm_widgets; const struct snd_soc_dapm_route *dapm_routes; int num_dapm_routes; .... } 2-In kernel/Documentation/sound/alsa/soc/platform.txt, states "The platform drivers only target the SoC CPU and must have no board specific code", but several CODEC drivers have struct snd_soc_platform_driver defined Is it an specifications missleading, or bad codec implementation? 3-Is there any document/guide to implement asoc driver, or ASOC is under development, and the mess should be organized I was looking for information at http://processors.wiki.ti.com/index.php/Sitara_Linux_Audio_DAC_Example kernel/Documentation/sound/alsa/soc ALSA home page (of curse writing alsa driver) http://blog.csdn.net/sepnic/article/category/778492 Several kernel source files (each manufacturer have his own way :( ) Thanks ind advance