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