On Wed, Sep 04, 2019 at 01:53:21AM +0900, Katsuhiro Suzuki wrote:
> This patch supports some type of machine drivers that use fixed clock
> rate. After applied this patch, sysclk == 0 means there is no
> constraint of sound rate and other values will set constraints which
> is derived by sysclk setting.

This is to support variable clock rate isn't it?