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| author | Xiubo Li <Li.Xiubo@freescale.com> | 2013-12-11 01:19:42 -0800 |
|---|---|---|
| committer | Bryan Wu <cooloney@gmail.com> | 2014-01-27 17:28:50 -0800 |
| commit | fc1aee038b609dc33067ca9dd477b16ea893cae0 (patch) | |
| tree | c098d278595f5efbdf7621969cf59d28aac6badf | |
| parent | 3df22c06b9ca7df02e095595994d229811305825 (diff) | |
| download | op-kernel-dev-fc1aee038b609dc33067ca9dd477b16ea893cae0.zip op-kernel-dev-fc1aee038b609dc33067ca9dd477b16ea893cae0.tar.gz | |
leds: leds-pwm: fix duty time overflow.
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.
Signed-off-by: Bryan Wu <cooloney@gmail.com>
| -rw-r--r-- | drivers/leds/leds-pwm.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index b31d8e9..3fbd28e 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); |
