Messages in this thread Patch in this message | | | From | Rasmus Villemoes <> | Subject | [PATCH v2 2/4] backlight: pwm_bl: eliminate a 64/32 division | Date | Tue, 8 Oct 2019 14:03:25 +0200 |
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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().
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- 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 cc44a02e95c7..672c5e7cfcd1 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -177,7 +177,7 @@ 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)); -- 2.20.1
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