linux-kernel - Re: [RESEND PATCH v2] mfd: syscon: Use a unique name with regmap

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Date:   Tue, 28 Jul 2020 09:44:27 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Suman Anna <s-anna@...com>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>,
        David Lechner <david@...hnology.com>,
        Tony Lindgren <tony@...mide.com>,
        Roger Quadros <rogerq@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-omap <linux-omap@...r.kernel.org>
Subject: Re: [RESEND PATCH v2] mfd: syscon: Use a unique name with regmap_config

On Mon, Jul 27, 2020 at 11:10 PM Suman Anna <s-anna@...com> wrote:
>
> The DT node full name is currently being used in regmap_config
> which in turn is used to create the regmap debugfs directories.
> This name however is not guaranteed to be unique and the regmap
> debugfs registration can fail in the cases where the syscon nodes
> have the same unit-address but are present in different DT node
> hierarchies. Replace this logic using the syscon reg resource
> address instead (inspired from logic used while creating platform
> devices) to ensure a unique name is given for each syscon.
>
> Signed-off-by: Suman Anna <s-anna@...com>
> ---
> Hi Arnd,
> Lee is looking for your review on this patch. Can you please
> review and provide your comments.

Sorry for missing this earlier. I think this makes sense, and I don't
expect the name change to cause problems, so

Reviewed-by: Arnd Bergmann <arnd@...db.de>

> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -101,12 +101,14 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
>                 }
>         }
>
> -       syscon_config.name = of_node_full_name(np);
> +       syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@...x", np,
> +                                      (u64)res.start);

Note that you could avoid the cast by using "%pOFn@%pa", and
passing res.start by reference. Not important though, the result should
be similar, and you might not like the '0x' that this adds.

      Arnd