Re: [PATCH v4 1/8] soc: renesas: rz-sysc: Add syscon/regmap support

From: Claudiu Beznea <claudiu.beznea@tuxon.dev>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: vkoul@kernel.org, kishon@kernel.org, robh@kernel.org,
	krzk+dt@kernel.org, conor+dt@kernel.org, p.zabel@pengutronix.de,
	magnus.damm@gmail.com, yoshihiro.shimoda.uh@renesas.com,
	biju.das.jz@bp.renesas.com, linux-phy@lists.infradead.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	John Madieu <john.madieu.xa@bp.renesas.com>,
	Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Subject: Re: [PATCH v4 1/8] soc: renesas: rz-sysc: Add syscon/regmap support
Date: Fri, 8 Aug 2025 15:11:01 +0300	[thread overview]
Message-ID: <277ca37d-e304-4d78-bfd9-b1fa222fd0f3@tuxon.dev> (raw)
In-Reply-To: <CAMuHMdXM=Mu+vJ6n3spj7Dd+8boLXEpcSn0M1KB8OwPijqq4aw@mail.gmail.com>

Hi, Geert,

On 08.08.2025 14:36, Geert Uytterhoeven wrote:
> Hi Claudiu,
> 
> On Fri, 8 Aug 2025 at 12:32, Claudiu Beznea <claudiu.beznea@tuxon.dev> wrote:
>> On 08.08.2025 12:29, Geert Uytterhoeven wrote:
>>> On Fri, 8 Aug 2025 at 08:18, Claudiu <claudiu.beznea@tuxon.dev> wrote:
>>>> From: John Madieu <john.madieu.xa@bp.renesas.com>
>>>>
>>>> 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,
>>>> register a custom regmap configuration.
>>>>
>>>> Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
>>>> [claudiu.beznea:
>>>>  - do not check the match->data validity in rz_sysc_probe() as it is
>>>>    always valid
>>>>  - dinamically allocate regmap_cfg]
>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>>> ---
>>>>
>>>> Changes in v4:
>>>> - adjusted the patch description by dropping "add" from
>>>>   "add register a custom regmap configuration"
>>>> - updated the list of changes from Claudiu Beznea
>>>> - dynamically allocate the regmap_config as proposed at [2]
>>>> - this patch is needed for proper function of USB (as proposed in this
>>>>   series) that being the reason it is introduced here, as well
>>>>
>>>> [2] https://lore.kernel.org/all/CAMuHMdVyf3Xtpw=LWHrnD2CVQX4xYm=FBHvY_dx9OesHDz5zNg@mail.gmail.com/
>>>
>>>> --- a/drivers/soc/renesas/rz-sysc.c
>>>> +++ b/drivers/soc/renesas/rz-sysc.c
>>> =
>>>> @@ -117,7 +125,26 @@ 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)
>>>> +               return ret;
>>>> +
>>>> +       regmap_cfg = devm_kzalloc(dev, sizeof(*regmap_cfg), GFP_KERNEL);
>>>> +       if (!regmap_cfg)
>>>> +               return -ENOMEM;
>>>
>>> Is there any specific reason you decided to allocate regmap_cfg
>>> separately, instead of embedding it into struct rz_sysc?
>>
>> Sorry, I missed to mention.
>>
>> I chose to have it like this as the regmap_cfg is not used anywhere else
>> (through rz_sysc) except in probe.
> 
> OK.  Upon closer look, devm_regmap_init_mmio() does not save the
> regmap_cfg pointer for later use, so it can be allocated using kzalloc()
> instead, and freed immediately after calling devm_regmap_init_mmio().

You're right, I forgot this. I'll update it this way.

Thank you,
Claudiu

> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 

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