Re: [PATCH] gpiolib: fix the size of the ngpios variable

[Andy Shevchenko]

On Sat, Mar 5, 2022 at 10:14 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:
>
> The ngpio fields both in struct gpio_device as well as gpio_chip are
> 16 bit unsigned integers. Let's not risk an overflow and use the correct
> size when reading the device property.

...

> -               ret = device_property_read_u32(&gdev->dev, "ngpios", &ngpios);
> +               ret = device_property_read_u16(&gdev->dev, "ngpios", &ngpios);

AFAIU DT format you may not do this. The property is ABI-like and it's
32-bit (BE!). Reading as u16 will bring you 2 MSB (bytes) out of 4
from the 32-bit value.

-- 
With Best Regards,
Andy Shevchenko