drm/i915: make g4x_digital_port_connected return boolean status

We should not be hitting any of the default cases in
g4x_digital_port_connected, so add MISSING_CASE annotation and return
boolean status. The current behaviour is just cargo culting from the
days of yonder when the display port support was added to i915.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -4525,14 +4525,14 @@ static bool ibx_digital_port_connected(struct drm_i915_private *dev_priv,
 	return I915_READ(SDEISR) & bit;
 }
 
-static int g4x_digital_port_connected(struct drm_device *dev,
-				       struct intel_digital_port *intel_dig_port)
+static bool g4x_digital_port_connected(struct drm_device *dev,
+				       struct intel_digital_port *port)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	uint32_t bit;
 
 	if (IS_VALLEYVIEW(dev)) {
-		switch (intel_dig_port->port) {
+		switch (port->port) {
 		case PORT_B:
 			bit = PORTB_HOTPLUG_LIVE_STATUS_VLV;
 			break;
@@ -4543,10 +4543,11 @@ static int g4x_digital_port_connected(struct drm_device *dev,
 			bit = PORTD_HOTPLUG_LIVE_STATUS_VLV;
 			break;
 		default:
-			return -EINVAL;
+			MISSING_CASE(port->port);
+			return false;
 		}
 	} else {
-		switch (intel_dig_port->port) {
+		switch (port->port) {
 		case PORT_B:
 			bit = PORTB_HOTPLUG_LIVE_STATUS_G4X;
 			break;
@@ -4557,13 +4558,12 @@ static int g4x_digital_port_connected(struct drm_device *dev,
 			bit = PORTD_HOTPLUG_LIVE_STATUS_G4X;
 			break;
 		default:
-			return -EINVAL;
+			MISSING_CASE(port->port);
+			return false;
 		}
 	}
 
-	if ((I915_READ(PORT_HOTPLUG_STAT) & bit) == 0)
-		return 0;
-	return 1;
+	return I915_READ(PORT_HOTPLUG_STAT) & bit;
 }
 
 static enum drm_connector_status
@@ -4584,7 +4584,6 @@ g4x_dp_detect(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
-	int ret;
 
 	/* Can't disconnect eDP, but you can close the lid... */
 	if (is_edp(intel_dp)) {
@@ -4596,10 +4595,7 @@ g4x_dp_detect(struct intel_dp *intel_dp)
 		return status;
 	}
 
-	ret = g4x_digital_port_connected(dev, intel_dig_port);
-	if (ret == -EINVAL)
-		return connector_status_unknown;
-	else if (ret == 0)
+	if (!g4x_digital_port_connected(dev, intel_dig_port))
 		return connector_status_disconnected;
 
 	return intel_dp_detect_dpcd(intel_dp);
@@ -5066,7 +5062,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 			if (!ibx_digital_port_connected(dev_priv, intel_dig_port))
 				goto mst_fail;
 		} else {
-			if (g4x_digital_port_connected(dev, intel_dig_port) != 1)
+			if (!g4x_digital_port_connected(dev, intel_dig_port))
 				goto mst_fail;
 		}