RE: [PATCH 11/13] clk: renesas: rzg2l-cpg: drop determine_rate op and use CLK_ROUNDING_FW_MANAGED flag

[Biju Das]

Hi Brian/Geert,

> -----Original Message-----
> From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Sent: 27 February 2026 15:09
> Subject: Re: [PATCH 11/13] clk: renesas: rzg2l-cpg: drop determine_rate op and use
> CLK_ROUNDING_FW_MANAGED flag
> 
> Hi Brian,
> 
> On Fri, 27 Feb 2026 at 16:01, Brian Masney <bmasney@xxxxxxxxxx> wrote:
> > On Fri, Feb 27, 2026 at 09:20:09AM +0100, Geert Uytterhoeven wrote:
> > > On Thu, 26 Feb 2026 at 19:18, Brian Masney <bmasney@xxxxxxxxxx> wrote:
> > > > This clk driver has a noop determine_rate clk op. Drop this empty
> > > > function, and enable the CLK_ROUNDING_FW_MANAGED flag.
> > > >
> > > > Signed-off-by: Brian Masney <bmasney@xxxxxxxxxx>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/drivers/clk/renesas/rzg2l-cpg.c
> > > > +++ b/drivers/clk/renesas/rzg2l-cpg.c
> 
> > > > @@ -1041,7 +1034,7 @@ rzg2l_cpg_sipll5_register(const struct cpg_core_clk *core,
> > > >         init.name = core->name;
> > > >         parent_name = __clk_get_name(parent);
> > > >         init.ops = &rzg2l_cpg_sipll5_ops;
> > > > -       init.flags = 0;
> > > > +       init.flags = CLK_ROUNDING_FW_MANAGED;
> > >
> > > Iff this is the Right Thing To Do (TM), it needs a comment, as this
> > > clock is not managed by firmware.
> >
> > Before I start a larger discussion on patch 1 with more people about a
> > name for this flag, help me understand why this provider has a noop
> > determine rate. Is the hardware eventually programmed with a rate
> > that's close enough to what was passed in? Or it doesn't really matter
> > what the clock rate is, just as long as it is running? Or should the
> > determine_rate function be filled out in this particular case?
> 
> I'd like to defer to Biju, who added the empty round^Wdetermine rate function.

PLL is capable of generating any frequency. that is the reason.

But we could, call rzg2l_cpg_get_foutpostdiv_rate() from determine_rate()
as modified rzg2l_cpg_get_foutpostdiv_rate()[1] can return errors

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/clk/renesas/rzg2l-cpg.c?h=next-20260227#n590


Cheers,
Biju