linux-kernel - Re: [PATCH] gpiolib: acpi: Fix failed in acpi_gpiochip

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Date: Mon, 13 May 2024 12:25:50 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Devyn Liu <liudingyuan@...wei.com>,
	Benjamin Tissoires <bentiss@...nel.org>
Cc: linus.walleij@...aro.org, brgl@...ev.pl, f.fangjian@...wei.com,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	mika.westerberg@...ux.intel.com, linux-acpi@...r.kernel.org,
	jonathan.cameron@...wei.com, yangyicong@...wei.com,
	yisen.zhuang@...wei.com, kong.kongxinwei@...ilicon.com
Subject: Re: [PATCH] gpiolib: acpi: Fix failed in acpi_gpiochip_find() by
 adding parent node match

On Mon, May 13, 2024 at 03:59:01PM +0800, Devyn Liu wrote:
> Previous patch modified the standard used by acpi_gpiochip_find()
> to match device nodes. Using the device node set in gc->gpiodev->d-
> ev instead of gc->parent.
> 
> However, there is a situation in gpio-dwapb where the GPIO device
> driver will set gc->fwnode for each port corresponding to a child
> node under a GPIO device, so gc->gpiodev->dev will be assigned the
> value of each child node in gpiochip_add_data().
> 
> gpio-dwapb.c:
> 128,31 static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
> 			       struct dwapb_port_property *pp,
> 			       unsigned int offs);
> port->gc.fwnode = pp->fwnode;
> 
> 693,39 static int dwapb_gpio_probe;
> err = dwapb_gpio_add_port(gpio, &pdata->properties[i], i);
> 
> When other drivers request GPIO pin resources through the GPIO device
> node provided by ACPI (corresponding to the parent node), the change
> of the matching object to gc->gpiodev->dev in acpi_gpiochip_find()
> only allows finding the value of each port (child node), resulting
> in a failed request.
> 
> Reapply the condition of using gc->parent for match in acpi_gpio-
> chip_find() in the code can compatible with the problem of gpio-dwapb,
> and will not affect the two cases mentioned in the patch:
> 1. There is no setting for gc->fwnode.
> 2. The case that depends on using gc->fwnode for match.

Thanks for the report, analysis, and patch.

..

>  static int acpi_gpiochip_find(struct gpio_chip *gc, const void *data)
>  {
> -	return device_match_acpi_handle(&gc->gpiodev->dev, data);
> +	return device_match_acpi_handle(&gc->gpiodev->dev, data) ||
> +		(gc->parent && device_match_acpi_handle(gc->parent, data));
>  }

I'm wondering if the below approach will work for all:

static int acpi_gpiochip_find(struct gpio_chip *gc, const void *data)
{
	struct device *dev = acpi_get_first_physical_node(ACPI_COMPANION(&gc->gpiodev->dev));

	return device_match_acpi_handle(dev, data);
}

Cc'ing to Benjamin for testing and commenting.

-- 
With Best Regards,
Andy Shevchenko