linux-kernel - Re: [PATCH v2 21/22] platform: Modify platform_get_irq

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Date: Thu, 21 Dec 2023 17:33:20 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mark Hasemeyer <markhas@...omium.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Raul Rangel <rrangel@...omium.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Rob Herring <robh@...nel.org>, Sudeep Holla <sudeep.holla@....com>,
	David Gow <davidgow@...gle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Mark Brown <broonie@...nel.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Takashi Iwai <tiwai@...e.de>,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Subject: Re: [PATCH v2 21/22] platform: Modify platform_get_irq_optional() to
 use resource

On Wed, Dec 20, 2023 at 04:54:35PM -0700, Mark Hasemeyer wrote:
> Unify handling of ACPI, GPIO, devictree, and platform resource
> interrupts in platform_get_irq_optional(). Each of these subsystems
> provide their own APIs which provide IRQ information as a struct
> resource. This simplifies the logic of the function and allows callers
> to get more information about the IRQ by looking at the resource flags.
> For example, whether or not an IRQ is wake capable.

...

>   * For example::
>   *
> - *		int irq = platform_get_irq_optional(pdev, 0);
> + *		int irq = platform_get_irq_resource_optional(pdev, 0, &res);
>   *		if (irq < 0)
>   *			return irq;
>   *
>   * Return: non-zero IRQ number on success, negative error number on failure.

Why do we need the irq to be returned via error code?

...

>  	int ret;

Missing blank line, have you run checkpatch.pl?

> +	if (IS_ERR_OR_NULL(r))
> +		return -EINVAL;

If we ever have an error pointer in r, I prefer to see

	if (!r)
		return -EINVAL;
	if (IS_ERR(r))
		return PTR_ERR(r);

But Q is the same as earlier: when would we have the error pointer in @r?

...

> +	platform_res = platform_get_resource(dev, IORESOURCE_IRQ, num);

I would move this closer to the condition...

>  	/*
>  	 * The resources may pass trigger flags to the irqs that need
>  	 * to be set up. It so happens that the trigger flags for
>  	 * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER*
>  	 * settings.
>  	 */

...i.e. here.

> -	if (r && r->flags & IORESOURCE_BITS) {
> +	if (platform_res && platform_res->flags & IORESOURCE_BITS) {

>  	}

...

>  	if (num == 0 && is_acpi_device_node(fwnode)) {
> -		ret = acpi_dev_gpio_irq_get(to_acpi_device_node(fwnode), num);
> +		ret = acpi_dev_get_gpio_irq_resource(to_acpi_device_node(fwnode), NULL, num, r);
>  		/* Our callers expect -ENXIO for missing IRQs. */

> -		if (ret >= 0 || ret == -EPROBE_DEFER)
> +		if (!ret || ret == -EPROBE_DEFER) {

Can we save this and be consistent with above fwnode API return code check?

> +			ret = ret ?: r->start;
>  			goto out;
> +		}
>  	}

...

> -EXPORT_SYMBOL_GPL(platform_get_irq_optional);
> +EXPORT_SYMBOL_GPL(platform_get_irq_resource_optional);
> +

Stray blank line change.

...

>  EXPORT_SYMBOL_GPL(platform_get_irq);
>  
> +

Ditto.

...

> +int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
> +{
> +	struct resource r;

	struct resource r = {};

?

> +	return platform_get_irq_resource_optional(dev, num, &r);
> +}

-- 
With Best Regards,
Andy Shevchenko