linux-kernel - Re: [PATCH 2/2] pinctrl: at91-pio4: Use platform_get_irq

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Message-ID: <CA+V-a8teu=9Eeyjd78Va1hEs7BCD_+zMSS_T_WPz82bXwvcgjw@mail.gmail.com>
Date:   Fri, 24 Dec 2021 15:09:42 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Rob Herring <robh+dt@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] pinctrl: at91-pio4: Use platform_get_irq_optional()
 to get the interrupt

Hi Alexandre,

Thank you for the review.

On Fri, Dec 24, 2021 at 3:03 PM Alexandre Belloni
<alexandre.belloni@...tlin.com> wrote:
>
> On 24/12/2021 14:57:48+0000, Lad Prabhakar wrote:
> > platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
> > allocation of IRQ resources in DT core code, this causes an issue
> > when using hierarchical interrupt domains using "interrupts" property
> > in the node as this bypasses the hierarchical setup and messes up the
> > irq chaining.
> >
> > In preparation for removal of static setup of IRQ resource from DT core
> > code use platform_get_irq_optional().
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > ---
> >  drivers/pinctrl/pinctrl-at91-pio4.c | 14 ++++++--------
> >  1 file changed, 6 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/pinctrl/pinctrl-at91-pio4.c b/drivers/pinctrl/pinctrl-at91-pio4.c
> > index fafd1f55cba7..ebfb106be97d 100644
> > --- a/drivers/pinctrl/pinctrl-at91-pio4.c
> > +++ b/drivers/pinctrl/pinctrl-at91-pio4.c
> > @@ -1045,7 +1045,6 @@ static int atmel_pinctrl_probe(struct platform_device *pdev)
> >       const char **group_names;
> >       const struct of_device_id *match;
> >       int i, ret;
> > -     struct resource *res;
> >       struct atmel_pioctrl *atmel_pioctrl;
> >       const struct atmel_pioctrl_data *atmel_pioctrl_data;
> >
> > @@ -1164,16 +1163,15 @@ static int atmel_pinctrl_probe(struct platform_device *pdev)
> >
> >       /* There is one controller but each bank has its own irq line. */
> >       for (i = 0; i < atmel_pioctrl->nbanks; i++) {
> > -             res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
> > -             if (!res) {
> > +             ret = platform_get_irq_optional(pdev, i);
>
> I don't think the irq should be optional here.
>
The only difference between platform_get_irq() and
platform_get_irq_optional() is that platform_get_irq() prints an error
message in case of error. Since we are already printing an sane error
message "missing irq resource for group %c\n" in the driver I've
chosen platform_get_irq_optional() instead platform_get_irq().

Let me know if you want me to drop platform_get_irq_optional() and use
platform_get_irq() instead, in that case I'll also drop the error
message "missing irq resource for group %c\n" from the driver.

Cheers,
Prabhakar

> > +             if (ret < 0) {
> >                       dev_err(dev, "missing irq resource for group %c\n",
> >                               'A' + i);
> > -                     return -EINVAL;
> > +                     return ret;
> >               }
> > -             atmel_pioctrl->irqs[i] = res->start;
> > -             irq_set_chained_handler_and_data(res->start,
> > -                     atmel_gpio_irq_handler, atmel_pioctrl);
> > -             dev_dbg(dev, "bank %i: irq=%pr\n", i, res);
> > +             atmel_pioctrl->irqs[i] = ret;
> > +             irq_set_chained_handler_and_data(ret, atmel_gpio_irq_handler, atmel_pioctrl);
> > +             dev_dbg(dev, "bank %i: irq=%d\n", i, ret);
> >       }
> >
> >       atmel_pioctrl->irq_domain = irq_domain_add_linear(dev->of_node,
> > --
> > 2.17.1
> >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com