[LAD] Hardware audio decoder driver design

Hello. Soon I will work on a linux kernel driver for a custom audio decoder device that is being developed by a company I work for. If not going into details, that devices reads A52-encoded stream from system memory, and writes raw pcm stream to system memory. Simplest thing to do is - implement a character device, where user-space will write encoded stream, and from where user-space will read decoded stream. (driver for similar hardware, located at http://sourceforge.net/projects/vs10xx/, does that). However, perhaps a better architecture (e.g. in-kernel intergation with an audio sink) is possible? I'm looking for any related information - e.g. ideas on what interface to implement, examples of drivers for similar devices, etc. Thanks on any hints. Nikita Youshchenko, embedded linux developer.