Re: [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag

From: Andy Shevchenko
Date: Thu Jul 22 2021 - 05:39:02 EST


On Thu, Jul 22, 2021 at 12:33 PM Liu Ying <victor.liu@xxxxxxx> wrote:
> On Fri, 2021-07-16 at 16:34 +0300, Andy Shevchenko wrote:
> > The newly introduced flag, when set, makes the flow to skip
> > the assumption that the caller will use an additional 2^scale
> > prescaler to get the desired clock rate.
>
> As I mentioned in v1 comment, it seems to be good to decouple the
> prescaler knowledge from this common fractional divider clk driver.
> This way, we'll make it simpler and easier to maintain. Also, then, the
> NO_PRESCALER flag is not needed at all. However, it seems that two
> Intel drivers which use the frational divider drivers will be affected
> and rate negotiation logics need to be implemented for them. Please
> consider if it's doable or not.

The current driver works for the certain hardware without this change.
If you think it's better, submit a proposal we will discuss.

> If we ultimately keep the prescaler knowledge here, please consider to
> add the NO_PRESCALER flag for i.MX7ulp as it hasn't the prescaler IIUC.

You mean there is a code which is currently using this driver w/o
taking into account this prescaller flavour? Can you, please, point
out, I'll definitely update it. Thanks for the catch!

--
With Best Regards,
Andy Shevchenko