From fc1aee038b609dc33067ca9dd477b16ea893cae0 Mon Sep 17 00:00:00 2001
From: Xiubo Li
Date: Wed, 11 Dec 2013 01:19:42 -0800
Subject: [PATCH] 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
---
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 b31d8e99c419..3fbd28e99b2c 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);
--
2.39.2