linux-kernel - Re: [PATCH v3] pinctrl: renesas: rzg2l: Drop the unnecessary pin configurations

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Message-ID: <CAMuHMdV5bn1CjqNKvrtgEUTq8iQPZyg4UVh44s=6Z81XF1-F5Q@mail.gmail.com>
Date: Tue, 30 Sep 2025 12:24:41 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Biju <biju.das.au@...il.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Biju Das <biju.das.jz@...renesas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>, linux-renesas-soc@...r.kernel.org, 
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] pinctrl: renesas: rzg2l: Drop the unnecessary pin configurations

Hi Biju,

On Tue, 9 Sept 2025 at 12:42, Biju <biju.das.au@...il.com> wrote:
> From: Biju Das <biju.das.jz@...renesas.com>
>
> There is no need to reconfigure the pin if the pin's configuration values
> are same as the reset values. E.g.: PS0 pin configuration for NMI function
> is PMC = 1 and PFC = 0 and is same as that of reset values. Currently the
> code is first setting it to GPIO HI-Z state and then again reconfiguring
> to NMI function leading to spurious IRQ. Drop the unnecessary pin
> configurations from the driver.
>
> Signed-off-by: Biju Das <biju.das.jz@...renesas.com>

> --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> @@ -541,9 +541,16 @@ static void rzg2l_pinctrl_set_pfc_mode(struct rzg2l_pinctrl *pctrl,
>                                        u8 pin, u8 off, u8 func)
>  {
>         unsigned long flags;
> -       u32 reg;
> +       u32 reg, pfc;
>
> +       /* Switching to GPIO is not required if reset value is same as func */
> +       reg = readb(pctrl->base + PMC(off));

I am updating the commit to move this assignment inside the spinlock
below.

>         spin_lock_irqsave(&pctrl->lock, flags);
> +       pfc = readl(pctrl->base + PFC(off));
> +       if ((reg & BIT(pin)) && (((pfc >> (pin * 4)) & PFC_MASK) == func)) {
> +               spin_unlock_irqrestore(&pctrl->lock, flags);
> +               return;
> +       }

To ease backporting "[PATCH v2] pinctrl: renesas: rzg2l: Fix ISEL
restore on resume"[1], I am rebasing this commit on top of the latter.

>
>         /* Set pin to 'Non-use (Hi-Z input protection)'  */
>         reg = readw(pctrl->base + PM(off));

[1] https://lore.kernel.org/20250912095308.3603704-1-claudiu.beznea.uj@bp.renesas.com

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