From e802cbafcbd250a88cbd4ea7f9afb9c0d4267c7a Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Tue, 8 Oct 2019 14:03:25 +0200
Subject: backlight: pwm_bl: Eliminate a 64/32 division
Git-commit: e802cbafcbd250a88cbd4ea7f9afb9c0d4267c7a
Patch-mainline: v5.5-rc1
References: bsc#1152489
lightness*1000 is nowhere near overflowing 32 bits, so we can just use
an ordinary 32/32 division, which is much cheaper than the 64/32 done
via do_div().
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/video/backlight/pwm_bl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 3525e04791ce..15d84da77ecd 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -178,7 +178,7 @@ static u64 cie1931(unsigned int lightness, unsigned int scale)
*/
lightness *= 100;
if (lightness <= (8 * scale)) {
- retval = DIV_ROUND_CLOSEST_ULL(lightness * 10, 9033);
+ retval = DIV_ROUND_CLOSEST(lightness * 10, 9033);
} else {
retval = int_pow((lightness + (16 * scale)) / 116, 3);
retval = DIV_ROUND_CLOSEST_ULL(retval, (scale * scale));
--
2.28.0