[U-Boot] [PATCH v2] video: backlight: fix pwm invertation

[marvin24 at posteo.de]

Fixes: 57e7775413 ("video: backlight: Parse PWM polarity cell")

set_pwm will always fail with -ENOSYS if pwm_set_invert is not implemented,
leaving the backlight dark. Fix this by returning no error if
pwm_set_invert is not implemented and no polarity change is requested.

v2: simplify logic

Signed-off-by: Marc Dietrich <marvin24 at gmx.de>
---
 drivers/video/pwm_backlight.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/pwm_backlight.c b/drivers/video/pwm_backlight.c
index a587977c22..ad20bf2441 100644
--- a/drivers/video/pwm_backlight.c
+++ b/drivers/video/pwm_backlight.c
@@ -67,6 +67,9 @@ static int set_pwm(struct pwm_backlight_priv *priv)
                return log_ret(ret);
 
        ret = pwm_set_invert(priv->pwm, priv->channel, priv->polarity);
+       if (ret == -ENOSYS && !priv->polarity)
+               ret = 0;
+
        return log_ret(ret);
 }
 
-- 
2.17.1