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>

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 3525e04791ced61a392f0dfb2dbcfaec6ef6e770..15d84da77ecde514e602e8a4cb4da5b6ab92e420 100644 (file)
--- 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));