Re: [PATCH v2] gpio: rockchip: resolve overflow issues
From: Heiko Stübner <heiko@sntech.de>
Date: 2024-08-23 09:33:55
Also in:
linux-gpio, linux-rockchip, lkml
Am Freitag, 23. August 2024, 05:43:06 CEST schrieb Ye Zhang:
Prevent overflow issues when performing debounce-related calculations.
Please add some more explanation here. I.e. something about previous max_debounce calculation does overflow the type of max_debounce Thanks Heiko
quoted hunk ↗ jump to hunk
Fixes: 3bcbd1a85b68 ("gpio/rockchip: support next version gpio controller") Signed-off-by: Ye Zhang <redacted> --- drivers/gpio/gpio-rockchip.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/drivers/gpio/gpio-rockchip.c b/drivers/gpio/gpio-rockchip.c index 5f60162baaeb..bf22b103b6a2 100644 --- a/drivers/gpio/gpio-rockchip.c +++ b/drivers/gpio/gpio-rockchip.c@@ -209,11 +209,12 @@ static int rockchip_gpio_set_debounce(struct gpio_chip *gc, freq = clk_get_rate(bank->db_clk); if (!freq) return -EINVAL; - max_debounce = (GENMASK(23, 0) + 1) * 2 * 1000000 / freq; + div = (u64)(GENMASK(23, 0) + 1) * 2 * 1000000; + max_debounce = DIV_ROUND_CLOSEST_ULL(div, freq); if (debounce > max_debounce) return -EINVAL; - div = debounce * freq; + div = (u64)debounce * freq; div_reg = DIV_ROUND_CLOSEST_ULL(div, 2 * USEC_PER_SEC) - 1; } else { div_debounce_support = false;