linux-kernel - Re: [PATCH v2 2/2] gpiolib: check the 'ngpios' property in core gpiolib code

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Message-ID: <YZaH8rsMyUztOX/r@smile.fi.intel.com>
Date:   Thu, 18 Nov 2021 19:05:54 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] gpiolib: check the 'ngpios' property in core
 gpiolib code

On Thu, Nov 18, 2021 at 02:23:17PM +0100, Bartosz Golaszewski wrote:
> Several drivers read the 'ngpios' device property on their own, but
> since it's defined as a standard GPIO property in the device tree bindings
> anyway, it's a good candidate for generalization. If the driver didn't
> set its gc->ngpio, try to read the 'ngpios' property from the GPIO
> device's firmware node before bailing out.

...

>  	if (gc->ngpio == 0) {
> -		chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> -		ret = -EINVAL;
> -		goto err_free_descs;
> +		ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> +		if (ret) {
> +			chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
> +			ret = -EINVAL;
> +			goto err_free_descs;
> +		}
> +
> +		gc->ngpio = ngpios;
>  	}

This should be

	if (gc->ngpio == 0) {
		ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
		if (ret)
			return ret;

		gc->ngpio = ngpios;
	}

	if (gc->ngpio == 0) {
		chip_err(gc, "tried to insert a GPIO chip with zero lines\n");
		ret = -EINVAL;
		goto err_free_descs;
	}

-- 
With Best Regards,
Andy Shevchenko