X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=drivers%2Fvideo%2Fbacklight%2Fpwm_bl.c;h=8d8959a70e44091f83e20561a711c93fb681cabf;hb=ac08b1c68d1b1ed3cebb218fc3ea2c07484eb07d;hp=e48fded3e414c9c45dd30099521b27397fc2238d;hpb=eda809aef53426d044b519405d25d9da55319b76;p=linux-2.6-microblaze.git

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index e48fded3e414..8d8959a70e44 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -409,6 +409,33 @@ static bool pwm_backlight_is_linear(struct platform_pwm_backlight_data *data)
 static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb)
 {
 	struct device_node *node = pb->dev->of_node;
+	bool active = true;
+
+	/*
+	 * If the enable GPIO is present, observable (either as input
+	 * or output) and off then the backlight is not currently active.
+	 * */
+	if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0)
+		active = false;
+
+	if (!regulator_is_enabled(pb->power_supply))
+		active = false;
+
+	if (!pwm_is_enabled(pb->pwm))
+		active = false;
+
+	/*
+	 * Synchronize the enable_gpio with the observed state of the
+	 * hardware.
+	 */
+	if (pb->enable_gpio)
+		gpiod_direction_output(pb->enable_gpio, active);
+
+	/*
+	 * Do not change pb->enabled here! pb->enabled essentially
+	 * tells us if we own one of the regulator's use counts and
+	 * right now we do not.
+	 */
 
 	/* Not booted with device tree or no phandle link to the node */
 	if (!node || !node->phandle)
@@ -420,20 +447,7 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb)
 	 * assume that another driver will enable the backlight at the
 	 * appropriate time. Therefore, if it is disabled, keep it so.
 	 */
-
-	/* if the enable GPIO is disabled, do not enable the backlight */
-	if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0)
-		return FB_BLANK_POWERDOWN;
-
-	/* The regulator is disabled, do not enable the backlight */
-	if (!regulator_is_enabled(pb->power_supply))
-		return FB_BLANK_POWERDOWN;
-
-	/* The PWM is disabled, keep it like this */
-	if (!pwm_is_enabled(pb->pwm))
-		return FB_BLANK_POWERDOWN;
-
-	return FB_BLANK_UNBLANK;
+	return active ? FB_BLANK_UNBLANK: FB_BLANK_POWERDOWN;
 }
 
 static int pwm_backlight_probe(struct platform_device *pdev)
@@ -486,18 +500,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		goto err_alloc;
 	}
 
-	/*
-	 * If the GPIO is not known to be already configured as output, that
-	 * is, if gpiod_get_direction returns either 1 or -EINVAL, change the
-	 * direction to output and set the GPIO as active.
-	 * Do not force the GPIO to active when it was already output as it
-	 * could cause backlight flickering or we would enable the backlight too
-	 * early. Leave the decision of the initial backlight state for later.
-	 */
-	if (pb->enable_gpio &&
-	    gpiod_get_direction(pb->enable_gpio) != 0)
-		gpiod_direction_output(pb->enable_gpio, 1);
-
 	pb->power_supply = devm_regulator_get(&pdev->dev, "power");
 	if (IS_ERR(pb->power_supply)) {
 		ret = PTR_ERR(pb->power_supply);