Re: [PATCH v2] gpio: rockchip: resolve underflow issue

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Fri, Aug 23, 2024 at 11:43:07AM +0800, Ye Zhang wrote:
> div_reg may be < 0 if debounce is zero, causing the unsigned int to
> overflow.

...

> -	if (bank->gpio_type == GPIO_TYPE_V2 && !IS_ERR(bank->db_clk)) {
> -		div_debounce_support = true;

Wouldn't be cleaner (from the patch perspective) to simply move else branch here?

	else
		div_debounce_support = false;

> +	div_debounce_support = (bank->gpio_type == GPIO_TYPE_V2) && !IS_ERR(bank->db_clk);
> +	if (debounce && div_debounce_support) {
>  		freq = clk_get_rate(bank->db_clk);
>  		if (!freq)
>  			return -EINVAL;
> @@ -216,8 +216,6 @@ static int rockchip_gpio_set_debounce(struct gpio_chip *gc,
>  
>  		div = (u64)debounce * freq;
>  		div_reg = DIV_ROUND_CLOSEST_ULL(div, 2 * USEC_PER_SEC) - 1;
> -	} else {
> -		div_debounce_support = false;
>  	}

-- 
With Best Regards,
Andy Shevchenko