On Tue, Sep 03, 2019 at 04:19:10AM +0900, Katsuhiro Suzuki wrote:
> On 2019/09/02 21:02, Mark Brown wrote:

> > The best way to handle this is to try to support both fixed and variable
> > clock rates, some other drivers do this by setting constraints based on
> > MCLK only if the MCLK has been set to a non-zero value.  They have the
> > machine drivers reset the clock rate to 0 when it goes idle so that no
> > constraints are applied then.  This means that if the machine has a

> In my understanding, fixed and variable clock both use set_sysclk() for
> telling their MCLK to codec driver. For fixed MCLK cases we need to
> apply constraint but for variable MCLK cases we should not set
> constraints at set_sysclk(). How can we identify these two cases...?

Like I say it's usually done by settingthe MCLK to 0 when not in use and
then not applying any constraints if there's no MCLK set.