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@xxxxxxxxxx>
---
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 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;
}
--
2.41.0
