On Wed, Dec 11, 2013 at 1:19 AM, Xiubo Li <[email protected]> wrote: > Overflow maybe occurs when calculates the duty time. For instance, > the period time is 990000000ns, and the max_brightness is 127, when > setting the brightness to 12, the duty value will be 25906026ns, but > it should be 93543307ns.
This looks good to me. Good catch. I will merge this. Thanks, -Bryan > --- > drivers/leds/leds-pwm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c > index bb6f948..7cb2cd8 100644 > --- a/drivers/leds/leds-pwm.c > +++ b/drivers/leds/leds-pwm.c > @@ -66,9 +66,11 @@ static void led_pwm_set(struct led_classdev *led_cdev, > struct led_pwm_data *led_dat = > container_of(led_cdev, struct led_pwm_data, cdev); > unsigned int max = led_dat->cdev.max_brightness; > - unsigned int period = led_dat->period; > + unsigned long long duty = led_dat->period; > > - led_dat->duty = brightness * period / max; > + duty *= brightness; > + do_div(duty, max); > + led_dat->duty = duty; > > if (led_dat->can_sleep) > schedule_work(&led_dat->work); > -- > 1.8.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
