linux-kernel - Re: [PATCH v3 1/4] clk: renesas: rzg2l-cpg: Move PM domain power on in rzg2l_cpg_pd

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Message-ID: <CAMuHMdWF=3svkFT8sVEtTahtDh3tJG4FjqmqhJJKs9JYNd+WCQ@mail.gmail.com>
Date: Mon, 7 Oct 2024 16:18:56 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Claudiu <claudiu.beznea@...on.dev>
Cc: mturquette@...libre.com, sboyd@...nel.org, wim@...ux-watchdog.org, 
	linux@...ck-us.net, ulf.hansson@...aro.org, linux-renesas-soc@...r.kernel.org, 
	linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-watchdog@...r.kernel.org, linux-pm@...r.kernel.org, 
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v3 1/4] clk: renesas: rzg2l-cpg: Move PM domain power on
 in rzg2l_cpg_pd_setup()

Hi Claudiu,

On Mon, Sep 2, 2024 at 3:24 PM Claudiu <claudiu.beznea@...on.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>
> Move the PM domain power on in rzg2l_cpg_pd_setup(). With this the
> previously always-on power domains got
> struct generic_pm_domain::{power_on, power_off} populated (and
> registered with simple_qos_governor if #power-domain-cells = <1> and
> with pm_domain_always_on_gov if #power-domain-cells = <0>). The values for
> struct generic_pm_domain::{power_on, power_off} are now populated for
> all registered domains but used by core only for the domains that can
> use them (the PM domain should be non always-on and registered with
> simple_qos_governor). Moreover, the power on/off functions check if the
> mstop support is valid. The mstop is populated only by the RZ/G3S
> initialization code at the moment.
>
> This approach was chosen to keep the code simple and use the same code
> across different implementations. There should be no issues with this
> approach as the always on domains are registered with GENPD_FLAG_ALWAYS_ON
> and the PM domain core takes care of it.
>
> This approach allows doing further cleanups on the rzg2l_cpg power domain
> registering code that will be handled by the next commit.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> ---
>
> Changes in v3:
> - none; this patch is new

Thanks for your patch!

> --- a/drivers/clk/renesas/rzg2l-cpg.c
> +++ b/drivers/clk/renesas/rzg2l-cpg.c
> @@ -1680,23 +1680,26 @@ static int rzg2l_cpg_power_off(struct generic_pm_domain *domain)
>         return 0;
>  }
>
> -static int __init rzg2l_cpg_pd_setup(struct rzg2l_cpg_pd *pd, bool always_on)
> +static int __init rzg2l_cpg_pd_setup(struct rzg2l_cpg_pd *pd,
> +                                    struct dev_power_governor *governor)
>  {
> -       struct dev_power_governor *governor;
> +       bool always_on = !!(pd->genpd.flags & GENPD_FLAG_ALWAYS_ON);
> +       int ret;
>
>         pd->genpd.flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
>         pd->genpd.attach_dev = rzg2l_cpg_attach_dev;
>         pd->genpd.detach_dev = rzg2l_cpg_detach_dev;
> -       if (always_on) {
> -               pd->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
> -               governor = &pm_domain_always_on_gov;
> -       } else {
> -               pd->genpd.power_on = rzg2l_cpg_power_on;
> -               pd->genpd.power_off = rzg2l_cpg_power_off;
> -               governor = &simple_qos_governor;
> -       }
> +       pd->genpd.power_on = rzg2l_cpg_power_on;
> +       pd->genpd.power_off = rzg2l_cpg_power_off;
> +
> +       ret = pm_genpd_init(&pd->genpd, governor, !always_on);
> +       if (ret)
> +               return ret;
> +
> +       if (governor == &simple_qos_governor && always_on)
> +               ret = rzg2l_cpg_power_on(&pd->genpd);

I think you can drop the check for simple_qos_governor: in the single
clock domain case, pd->conf.mstop is zero, so rzg2l_cpg_power_{off,on}()
become no-ops.  That would also allow you to drop passing the governor
as a parameter, as it can be set based on the always_on flag, as before.

Regardless:
Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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