@@ -409,6 +409,33 @@ static bool pwm_backlight_is_linear(stru
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_s
* 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 pl
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);