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: <90990ed5-5c98-4a10-8593-bb3331a8c3a4@tuxon.dev>
Date: Wed, 9 Oct 2024 11:18:32 +0300
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
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, Geert,

On 07.10.2024 17:18, Geert Uytterhoeven wrote:
> 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

I remember I tried this but I don't remember for sure why I kept it like
here. I'll double check it anyway.

Thank you,
Claudiu Beznea

> 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
>