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authorXiubo Li <Li.Xiubo@freescale.com>2013-12-11 01:19:42 -0800
committerBryan Wu <cooloney@gmail.com>2014-01-27 17:28:50 -0800
commitfc1aee038b609dc33067ca9dd477b16ea893cae0 (patch)
treec098d278595f5efbdf7621969cf59d28aac6badf
parent3df22c06b9ca7df02e095595994d229811305825 (diff)
downloadop-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.c6
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);
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