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backlight: pwm_bl: Eliminate a 64/32 division 

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>
This commit is contained in:
Rasmus Villemoes 2019-10-08 14:03:25 +02:00 committed by Lee Jones
parent efdf690e15
commit e802cbafcb
1 changed files with 1 additions and 1 deletions
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2
drivers/video/backlight/pwm_bl.c
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@ -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));