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>

Author: Linus Walleij

drivers/video/backlight/ktd253-backlight.c

@@ -137,22 +137,16 @@ 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)
 			dev_err(dev, "gpio line missing or invalid.\n");
 		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);