The KTD253 backlight might already be on when the driver is probed: then we don't really know what the current ratio is and all light intensity settings will be off relative to what it was at boot.
To fix this, bring up the backlight OFF then move it to the default backlight from there so we know the state.
Signed-off-by: Linus Walleij linus.walleij@linaro.org --- drivers/video/backlight/ktd253-backlight.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/video/backlight/ktd253-backlight.c b/drivers/video/backlight/ktd253-backlight.c index e3fee3f1f582..d7b287cffd5c 100644 --- a/drivers/video/backlight/ktd253-backlight.c +++ b/drivers/video/backlight/ktd253-backlight.c @@ -137,15 +137,7 @@ static int ktd253_backlight_probe(struct platform_device *pdev) brightness = max_brightness; }
- if (brightness) - /* This will be the default ratio when the KTD253 is enabled */ - ktd253->ratio = KTD253_MAX_RATIO; - else - ktd253->ratio = 0; - - ktd253->gpiod = devm_gpiod_get(dev, "enable", - brightness ? GPIOD_OUT_HIGH : - GPIOD_OUT_LOW); + ktd253->gpiod = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW); if (IS_ERR(ktd253->gpiod)) { ret = PTR_ERR(ktd253->gpiod); if (ret != -EPROBE_DEFER) @@ -153,6 +145,8 @@ static int ktd253_backlight_probe(struct platform_device *pdev) return ret; } gpiod_set_consumer_name(ktd253->gpiod, dev_name(dev)); + /* Bring backlight to a known off state */ + msleep(KTD253_T_OFF_MS);
bl = devm_backlight_device_register(dev, dev_name(dev), dev, ktd253, &ktd253_backlight_ops, NULL);