backlight: ktd253: Bring up in a known state

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>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/video/backlight/ktd253-backlight.c b/drivers/video/backlight/ktd253-backlight.c
index e3fee3f1f58280cf6cc542f6abf436ef696fe5e7..d7b287cffd5cb6ef69915df6ee514b1f8521ba07 100644 (file)
--- 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);