Re: [PATCH 2/3] clk: renesas: rcar-usb2-clock-sel: Add multiple clocks management

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Shimoda-san,

On Fri, Oct 25, 2019 at 10:44 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com> wrote:
> > From: Geert Uytterhoeven, Sent: Friday, October 25, 2019 4:47 PM
> > On Fri, Oct 25, 2019 at 3:36 AM Yoshihiro Shimoda
> > <yoshihiro.shimoda.uh@renesas.com> wrote:
> > > > From: Geert Uytterhoeven, Sent: Thursday, October 24, 2019 8:35 PM
> > > <snip>
> > > > > --- a/drivers/clk/renesas/rcar-usb2-clock-sel.c
> > > > > +++ b/drivers/clk/renesas/rcar-usb2-clock-sel.c
> >
> > > > > @@ -131,6 +156,14 @@ static int rcar_usb2_clock_sel_probe(struct platform_device *pdev)
> > > > >         pm_runtime_enable(dev);
> > > > >         pm_runtime_get_sync(dev);
> > > >
> > > > pm_runtime_get_sync() will have already enabled the first module clock listed in
> > > > the DT "clocks" property.
> > > >
> > > > If you want the driver to manage all clocks itself, perhaps the PM Runtime
> > > > calls should be dropped?
> > >
> > > I'm thinking PM Runtime calls are related to power domain control so that we cannot
> > > drop it. Or, since the hardware is the Always-on domain, can we drop it anyway?
> >
> > That's right: if the hardware block ever ends up in a non-always-on
> > power domain,
> > you won't have a choice but to use PM Runtime.
>
> So, should I keep the PM Runtime calls?

I think they're good to have.
Just make sure the PM Runtime status matches the state of the other
clocks.

> # In such the case, I should add to describe power-domains property into
> # the dt-binding doc though :)

Indeed.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds