Re: [PATCH v2 0/8] clk: renesas: rcar-gen2/gen3: Switch to .determine_rate()

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Quoting Geert Uytterhoeven (2019-09-03 23:51:10)
> Hi Stephen,
> 
> On Wed, Sep 4, 2019 at 12:09 AM Stephen Boyd <sboyd@xxxxxxxxxx> wrote:
> > Quoting Geert Uytterhoeven (2019-08-30 06:45:07)
> > > As the .round_rate() callback returns a long clock rate, it cannot
> > > return clock rates that do not fit in signed long, but do fit in
> > > unsigned long.  The newer .determine_rate() callback does not suffer
> > > from this limitation.  In addition, .determine_rate() provides the
> > > ability to specify a rate range.
> > >
> > > This patch series performs the customary preparatory cleanups, and
> > > switches the Z (CPU) and SD clocks in the R-Car Gen2 and Gen3 clock
> > > drivers from the .round_rate() to the .determine_rate() callback.
> > > Note that the "div6" clock driver hasn't been converted yet, so div6
> > > clocks still use .round_rate().
> > >
> > > Changes compared to v1[1]:
> > >   - Add preparatory arithmetic division improvements
> > >   - Split off cpg_sd_clock_calc_div() absorption and SD clock best rate
> > >     calculation,
> > >   - Use div_u64() for division by unsigned long,
> > >
> > > This has been tested on R-Car M2-W and various R-Car Gen3, and should
> > > have no behavioral impact.
> >
> > From what I recall the rate range code is broken but I can't remember
> > how. Anyway, I was just curious if you ran into any issues with that
> > code.
> 
> I didn't ran into any issues.  But please note that in all tested cases, the
> limits were 0 and ULONG_MAX anyway, so probably it didn't trigger the
> broken cases in the rate range code.
> 
> So, is it good to have .determine_rate() support in individual clock drivers
> now, or do you want me to postpone the last 3 patches of my series until the
> rate range code is fixed?
> 

It's fine to use .determine_rate() because we'll fix the problems in the
clk framework. So no concern from me here. Just curious if you ran into
any problems.





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