linux-kernel - Re: [PATCH v3 14/15] pinctrl: renesas: pinctrl-rzg2l: Acquire lock in rzg2l_pinctrl_pm_setup

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Date: Wed, 5 Jun 2024 14:32:53 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Magnus Damm <magnus.damm@...il.com>, linux-renesas-soc@...r.kernel.org, 
	linux-gpio@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Biju Das <biju.das.jz@...renesas.com>, 
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Paul Barker <paul.barker.ct@...renesas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v3 14/15] pinctrl: renesas: pinctrl-rzg2l: Acquire lock in rzg2l_pinctrl_pm_setup_pfc()

On Thu, May 30, 2024 at 7:42 PM Prabhakar <prabhakar.csengg@...il.com> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> To keep consistency with rzg2l_pinctrl_set_pfc_mode(), acquire the lock
> in rzg2l_pinctrl_pm_setup_pfc() during PFC setup.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> ---
> v2->v3
> - New patch

Thanks for your patch!

> --- a/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzg2l.c
> @@ -2541,7 +2541,9 @@ static void rzg2l_pinctrl_pm_setup_dedicated_regs(struct rzg2l_pinctrl *pctrl, b
>  static void rzg2l_pinctrl_pm_setup_pfc(struct rzg2l_pinctrl *pctrl)
>  {
>         u32 nports = pctrl->data->n_port_pins / RZG2L_PINS_PER_PORT;
> +       unsigned long flags;
>
> +       spin_lock_irqsave(&pctrl->lock, flags);
>         pctrl->data->pwpr_pfc_lock_unlock(pctrl, false);
>
>         /* Restore port registers. */
> @@ -2586,6 +2588,7 @@ static void rzg2l_pinctrl_pm_setup_pfc(struct rzg2l_pinctrl *pctrl)
>         }
>
>         pctrl->data->pwpr_pfc_lock_unlock(pctrl, true);
> +       spin_unlock_irqrestore(&pctrl->lock, flags);
>  }
>
>  static int rzg2l_pinctrl_suspend_noirq(struct device *dev)

It's definitely safer to unlock only while holding the lock.

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

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