| Message ID | 20190919140620.32407-2-linux@rasmusvillemoes.dk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] backlight: pwm_bl: fix cie1913 comments and constant | expand |
On Thu, Sep 19, 2019 at 04:06:17PM +0200, Rasmus Villemoes wrote: > 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> > --- > 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 be36be1cacb7..9252d51f31b9 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
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index be36be1cacb7..9252d51f31b9 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));
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> --- drivers/video/backlight/pwm_bl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)