drm/i915: Introduce intel_hpd_pin function.

The idea is to have an unique place to decide the pin-port
per platform.

So let's create this function now without any functional
change. Just adding together code from hdmi and dp together.

v2: Add missing pin for port A.
v3: Fix typo on subject.
    Avoid behaviour change so add WARN_ON and return
    if port A on HDMI. (by DK).

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170811182650.14327-2-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -3195,6 +3195,7 @@ void intel_hpd_init(struct drm_i915_private *dev_priv);
 void intel_hpd_init_work(struct drm_i915_private *dev_priv);
 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv);
 enum port intel_hpd_pin_to_port(enum hpd_pin pin);
+enum hpd_pin intel_hpd_pin(enum port port);
 bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
 void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
 

drivers/gpu/drm/i915/intel_dp.c

@@ -5916,26 +5916,22 @@ intel_dp_init_connector_port_info(struct intel_digital_port *intel_dig_port)
 	struct intel_encoder *encoder = &intel_dig_port->base;
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
 
+	encoder->hpd_pin = intel_hpd_pin(intel_dig_port->port);
+
 	switch (intel_dig_port->port) {
 	case PORT_A:
-		encoder->hpd_pin = HPD_PORT_A;
 		intel_dp->aux_power_domain = POWER_DOMAIN_AUX_A;
 		break;
 	case PORT_B:
-		encoder->hpd_pin = HPD_PORT_B;
 		intel_dp->aux_power_domain = POWER_DOMAIN_AUX_B;
 		break;
 	case PORT_C:
-		encoder->hpd_pin = HPD_PORT_C;
 		intel_dp->aux_power_domain = POWER_DOMAIN_AUX_C;
 		break;
 	case PORT_D:
-		encoder->hpd_pin = HPD_PORT_D;
 		intel_dp->aux_power_domain = POWER_DOMAIN_AUX_D;
 		break;
 	case PORT_E:
-		encoder->hpd_pin = HPD_PORT_E;
-
 		/* FIXME: Check VBT for actual wiring of PORT E */
 		intel_dp->aux_power_domain = POWER_DOMAIN_AUX_D;
 		break;

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1920,23 +1920,9 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
 
 	intel_hdmi->ddc_bus = intel_hdmi_ddc_pin(dev_priv, port);
 
-	switch (port) {
-	case PORT_B:
-		intel_encoder->hpd_pin = HPD_PORT_B;
-		break;
-	case PORT_C:
-		intel_encoder->hpd_pin = HPD_PORT_C;
-		break;
-	case PORT_D:
-		intel_encoder->hpd_pin = HPD_PORT_D;
-		break;
-	case PORT_E:
-		intel_encoder->hpd_pin = HPD_PORT_E;
-		break;
-	default:
-		MISSING_CASE(port);
+	if (WARN_ON(port == PORT_A))
 		return;
-	}
+	intel_encoder->hpd_pin = intel_hpd_pin(port);
 
 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
 		intel_hdmi->write_infoframe = vlv_write_infoframe;

drivers/gpu/drm/i915/intel_hotplug.c

@@ -101,6 +101,32 @@ enum port intel_hpd_pin_to_port(enum hpd_pin pin)
 	}
 }
 
+/**
+ * intel_hpd_pin - return pin hard associated with certain port.
+ * @port: the hpd port to get associated pin
+ *
+ * Return pin that is associatade with @port and HDP_NONE if no pin is
+ * hard associated with that @port.
+ */
+enum hpd_pin intel_hpd_pin(enum port port)
+{
+	switch (port) {
+	case PORT_A:
+		return HPD_PORT_A;
+	case PORT_B:
+		return HPD_PORT_B;
+	case PORT_C:
+		return HPD_PORT_C;
+	case PORT_D:
+		return HPD_PORT_D;
+	case PORT_E:
+		return HPD_PORT_E;
+	default:
+		MISSING_CASE(port);
+		return HPD_NONE;
+	}
+}
+
 #define HPD_STORM_DETECT_PERIOD		1000
 #define HPD_STORM_REENABLE_DELAY	(2 * 60 * 1000)