linux-kernel - Re: [PATCH v2 5/5] gpiolib: Reuse device's fwnode to create IRQ domain

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Date:   Mon, 8 Mar 2021 19:32:47 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Marc Zyngier <maz@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH v2 5/5] gpiolib: Reuse device's fwnode to create IRQ domain

On Thu, Mar 4, 2021 at 4:02 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> When IRQ domain is created for an ACPI case, the name of it becomes unknown-%d
> since for now it utilizes of_node member only and doesn't consider fwnode case.
> Convert IRQ domain creation code to utilize fwnode instead.
>
> Before/After the change on Intel Galileo Gen 2 with two GPIO (IRQ) controllers:
>
>   unknown-1     ==>     \_SB.PCI0.GIP0.GPO
>   unknown-2     ==>     \_SB.NIO3
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/gpio/gpiolib.c | 28 ++++++++--------------------
>  1 file changed, 8 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 6827736ba05c..254d59b088fe 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1457,9 +1457,9 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
>                                 struct lock_class_key *lock_key,
>                                 struct lock_class_key *request_key)
>  {
> +       struct fwnode_handle *fwnode = dev_fwnode(&gc->gpiodev->dev);
>         struct irq_chip *irqchip = gc->irq.chip;
> -       const struct irq_domain_ops *ops = NULL;
> -       struct device_node *np;
> +       const struct irq_domain_ops *ops;
>         unsigned int type;
>         unsigned int i;
>
> @@ -1471,7 +1471,6 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
>                 return -EINVAL;
>         }
>
> -       np = gc->gpiodev->dev.of_node;
>         type = gc->irq.default_type;
>
>         /*
> @@ -1479,16 +1478,10 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
>          * used to configure the interrupts, as you may end up with
>          * conflicting triggers. Tell the user, and reset to NONE.
>          */
> -       if (WARN(np && type != IRQ_TYPE_NONE,
> -                "%s: Ignoring %u default trigger\n", np->full_name, type))
> +       if (WARN(fwnode && type != IRQ_TYPE_NONE,
> +                "%pfw: Ignoring %u default trigger\n", fwnode, type))
>                 type = IRQ_TYPE_NONE;
>
> -       if (has_acpi_companion(gc->parent) && type != IRQ_TYPE_NONE) {
> -               acpi_handle_warn(ACPI_HANDLE(gc->parent),
> -                                "Ignoring %u default trigger\n", type);
> -               type = IRQ_TYPE_NONE;
> -       }

Why is the above message not worth printing any more?  If there is a
good enough reason, it would be good to mention it in the changelog.

> -
>         if (gc->to_irq)
>                 chip_warn(gc, "to_irq is redefined in %s and you shouldn't rely on it\n", __func__);
>
> @@ -1504,15 +1497,10 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
>                         return ret;
>         } else {
>                 /* Some drivers provide custom irqdomain ops */
> -               if (gc->irq.domain_ops)
> -                       ops = gc->irq.domain_ops;
> -
> -               if (!ops)
> -                       ops = &gpiochip_domain_ops;

I'm guessing that the code above is replaced in order to avoid
initializing ops to NULL, but IMO that should be a separate patch or
at least the extra cleanup should be mentioned in the changelog.

Personally, I would do the essential change first and put all of the
tangentially related cleanups into a separate follow-up patch.

> -               gc->irq.domain = irq_domain_add_simple(np,
> -                       gc->ngpio,
> -                       gc->irq.first,
> -                       ops, gc);
> +               ops = gc->irq.domain_ops ?: &gpiochip_domain_ops;
> +               gc->irq.domain = irq_domain_create_simple(fwnode, gc->ngpio,
> +                                                                 gc->irq.first,
> +                                                                 ops, gc);
>                 if (!gc->irq.domain)
>                         return -EINVAL;
>         }
> --