video: backlight: pwm: avoid integer overflow in duty cycle calculation
The intermediate value could overflow for large periods and levels.
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/video/pwm_backlight.c b/drivers/video/pwm_backlight.c
index d7c0969..46c16a8 100644
--- a/drivers/video/pwm_backlight.c
+++ b/drivers/video/pwm_backlight.c
@@ -63,7 +63,7 @@
int ret;
if (priv->period_ns) {
- duty_cycle = priv->period_ns * (priv->cur_level - priv->min_level) /
+ duty_cycle = (u64)priv->period_ns * (priv->cur_level - priv->min_level) /
(priv->max_level - priv->min_level);
ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
duty_cycle);