linux-kernel - RE: [PATCH v6 1/5] soc: renesas: rz-sysc: Add syscon/regmap support

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Message-ID:
 <OSCPR01MB14647AC1598F8D20657366260FF22A@OSCPR01MB14647.jpnprd01.prod.outlook.com>
Date: Tue, 5 Aug 2025 12:38:13 +0000
From: John Madieu <john.madieu.xa@...renesas.com>
To: geert <geert@...ux-m68k.org>
CC: "conor+dt@...nel.org" <conor+dt@...nel.org>, "daniel.lezcano@...aro.org"
	<daniel.lezcano@...aro.org>, "krzk+dt@...nel.org" <krzk+dt@...nel.org>,
	"rafael@...nel.org" <rafael@...nel.org>, Biju Das
	<biju.das.jz@...renesas.com>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "john.madieu@...il.com"
	<john.madieu@...il.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-pm@...r.kernel.org"
	<linux-pm@...r.kernel.org>, "linux-renesas-soc@...r.kernel.org"
	<linux-renesas-soc@...r.kernel.org>, "lukasz.luba@....com"
	<lukasz.luba@....com>, magnus.damm <magnus.damm@...il.com>, "robh@...nel.org"
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	"niklas.soderlund+renesas@...natech.se"
	<niklas.soderlund+renesas@...natech.se>, Claudiu Beznea
	<claudiu.beznea.uj@...renesas.com>
Subject: RE: [PATCH v6 1/5] soc: renesas: rz-sysc: Add syscon/regmap support

Hi Geert,

Thanks for your review!

> -----Original Message-----
> From: Geert Uytterhoeven <geert@...ux-m68k.org>
> Sent: Monday, August 4, 2025 11:19 AM
> To: John Madieu <john.madieu.xa@...renesas.com>
> Subject: Re: [PATCH v6 1/5] soc: renesas: rz-sysc: Add syscon/regmap
> support
> 
> Hi John,
> 
> On Thu, 22 May 2025 at 20:23, John Madieu <john.madieu.xa@...renesas.com>
> wrote:
> > The RZ/G3E system controller has various registers that control or
> > report some properties specific to individual IPs. The regmap is
> > registered as a syscon device to allow these IP drivers to access the
> > registers through the regmap API.
> >
> > As other RZ SoCs might have custom read/write callbacks or
> > max-offsets, add register a custom regmap configuration.
> >
> > Signed-off-by: John Madieu <john.madieu.xa@...renesas.com>
> > [claudiu.beznea:
> >  - s/rzg3e_sysc_regmap/rzv2h_sysc_regmap in RZ/V2H sysc
> >    file
> >  - do not check the match->data validity in rz_sysc_probe() as it is
> >    always valid
> >  - register the regmap if data->regmap_cfg is valid]
> > Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> 
> Thanks for your patch!
> 
> As you probably noticed, I am not a big fan of syscon, so I try to avoid
> getting involved with syscon patches as much as possible.
> But this patch has appeared in multiple series, so I am afraid I cannot
> avoid it anymore ;-)
> 
> > --- a/drivers/soc/renesas/r9a08g045-sysc.c
> > +++ b/drivers/soc/renesas/r9a08g045-sysc.c
> > @@ -18,6 +18,16 @@ static const struct rz_sysc_soc_id_init_data
> rzg3s_sysc_soc_id_init_data __initc
> >         .specific_id_mask = GENMASK(27, 0),  };
> >
> > +static const struct regmap_config rzg3s_sysc_regmap __initconst = {
> > +       .name = "rzg3s_sysc_regs",
> > +       .reg_bits = 32,
> > +       .reg_stride = 4,
> > +       .val_bits = 32,
> > +       .fast_io = true,
> > +       .max_register = 0xe20,
> > +};
> 
> Struct regmap_config is a rather large structure, and the only SoC-specific
> members are the .name (which doesn't really matter) and .max_register
> members.  Hence please move .max_register back to struct rz_sysc_init_data
> (like in v5), and allocate struct regmap_config dynamically (by embedding
> it into struct rz_sysc).
> 
> > +
> >  const struct rz_sysc_init_data rzg3s_sysc_init_data __initconst = {
> >         .soc_id_init_data = &rzg3s_sysc_soc_id_init_data,
> > +       .regmap_cfg = &rzg3s_sysc_regmap,
> >  };
> 
> > --- a/drivers/soc/renesas/rz-sysc.c
> > +++ b/drivers/soc/renesas/rz-sysc.c
> > @@ -117,7 +124,15 @@ static int rz_sysc_probe(struct platform_device
> *pdev)
> >                 return PTR_ERR(sysc->base);
> >
> >         sysc->dev = dev;
> > -       return rz_sysc_soc_init(sysc, match);
> > +       ret = rz_sysc_soc_init(sysc, match);
> > +       if (ret || !data->regmap_cfg)
> 
> data->regmap_cfg should never be NULL (but this doesn't matter anymore,
> in the context of my request above).
> 
> > +               return ret;
> > +
> > +       regmap = devm_regmap_init_mmio(dev, sysc->base, data-
> >regmap_cfg);
> > +       if (IS_ERR(regmap))
> > +               return PTR_ERR(regmap);
> > +
> > +       return of_syscon_register_regmap(dev->of_node, regmap);
> >  }
> 
> The rest LGTM.

Will make the changes as per the v5. Thanks!

> 
> 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

Regards,
John