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| author | Marek Behún <kabel@kernel.org> | 2023-08-01 15:49:31 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-09-13 10:42:58 +0300 |
| commit | a253c416e67d4de9a338c8367c69ad85bb88253c (patch) | |
| tree | 10604eee2ff988fc6c3e9db9bf5df3ecbfb8f86c | |
| parent | 2804cc3508045eaa202c5f3afb0686b63672ad0b (diff) | |
| download | linux-a253c416e67d4de9a338c8367c69ad85bb88253c.tar.xz | |
leds: multicolor: Use rounded division when calculating color components
[ 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 <kabel@kernel.org>
Link: https://lore.kernel.org/r/20230801124931.8661-1-kabel@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/leds/led-class-multicolor.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c index e317408583df..ec62a4811613 100644 --- a/drivers/leds/led-class-multicolor.c +++ b/drivers/leds/led-class-multicolor.c @@ -6,6 +6,7 @@ #include <linux/device.h> #include <linux/init.h> #include <linux/led-class-multicolor.h> +#include <linux/math.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/uaccess.h> @@ -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; } |