From a253c416e67d4de9a338c8367c69ad85bb88253c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marek=20Beh=C3=BAn?= Date: Tue, 1 Aug 2023 14:49:31 +0200 Subject: [PATCH] leds: multicolor: Use rounded division when calculating color components MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 065d099f1be58187e6629273c50b948a02b7e1bf ] Given channel intensity, LED brightness and max LED brightness, the multicolor LED framework helper led_mc_calc_color_components() computes the color channel brightness as chan_brightness = brightness * chan_intensity / max_brightness Consider the situation when (brightness, intensity, max_brightness) is for example (16, 15, 255), then chan_brightness is computed to 0 although the fractional divison would give 0.94, which should be rounded to 1. Use DIV_ROUND_CLOSEST here for the division to give more realistic component computation: chan_brightness = DIV_ROUND_CLOSEST(brightness * chan_intensity, max_brightness) Fixes: 55d5d3b46b08 ("leds: multicolor: Introduce a multicolor class definition") Signed-off-by: Marek Behún Link: https://lore.kernel.org/r/20230801124931.8661-1-kabel@kernel.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin --- drivers/leds/led-class-multicolor.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c index e317408583df9..ec62a48116135 100644 --- a/drivers/leds/led-class-multicolor.c +++ b/drivers/leds/led-class-multicolor.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -19,9 +20,10 @@ int led_mc_calc_color_components(struct led_classdev_mc *mcled_cdev, int i; for (i = 0; i < mcled_cdev->num_colors; i++) - mcled_cdev->subled_info[i].brightness = brightness * - mcled_cdev->subled_info[i].intensity / - led_cdev->max_brightness; + mcled_cdev->subled_info[i].brightness = + DIV_ROUND_CLOSEST(brightness * + mcled_cdev->subled_info[i].intensity, + led_cdev->max_brightness); return 0; }