drm/i915: Simplify hpd pin to port

We will soon need to make that pin port association per
platform, so let's try to simplify it beforehand.

Also we are moving the backwards port to pin
here as well so let's use a standardized way.

One extra possibility here would be to add a
MISSING_CASE along with PORT_NONE, but I don't want
to change this behaviour for now.

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/20170811182650.14327-1-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -3194,7 +3194,7 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 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);
-bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port);
+enum port intel_hpd_pin_to_port(enum hpd_pin pin);
 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/i915_irq.c

@@ -1501,7 +1501,8 @@ static void intel_get_hpd_pins(u32 *pin_mask, u32 *long_mask,
 
 		*pin_mask |= BIT(i);
 
-		if (!intel_hpd_pin_to_port(i, &port))
+		port = intel_hpd_pin_to_port(i);
+		if (port == PORT_NONE)
 			continue;
 
 		if (long_pulse_detect(port, dig_hotplug_reg))

drivers/gpu/drm/i915/intel_dp.c

@@ -4578,7 +4578,7 @@ static bool bxt_digital_port_connected(struct drm_i915_private *dev_priv,
 	enum port port;
 	u32 bit;
 
-	intel_hpd_pin_to_port(intel_encoder->hpd_pin, &port);
+	port = intel_hpd_pin_to_port(intel_encoder->hpd_pin);
 	switch (port) {
 	case PORT_A:
 		bit = BXT_DE_PORT_HP_DDIA;

drivers/gpu/drm/i915/intel_hotplug.c

@@ -76,26 +76,28 @@
  * it will use i915_hotplug_work_func where this logic is handled.
  */
 
-bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port)
+/**
+ * intel_hpd_port - return port hard associated with certain pin.
+ * @pin: the hpd pin to get associated port
+ *
+ * Return port that is associatade with @pin and PORT_NONE if no port is
+ * hard associated with that @pin.
+ */
+enum port intel_hpd_pin_to_port(enum hpd_pin pin)
 {
 	switch (pin) {
 	case HPD_PORT_A:
-		*port = PORT_A;
-		return true;
+		return PORT_A;
 	case HPD_PORT_B:
-		*port = PORT_B;
-		return true;
+		return PORT_B;
 	case HPD_PORT_C:
-		*port = PORT_C;
-		return true;
+		return PORT_C;
 	case HPD_PORT_D:
-		*port = PORT_D;
-		return true;
+		return PORT_D;
 	case HPD_PORT_E:
-		*port = PORT_E;
-		return true;
+		return PORT_E;
 	default:
-		return false;	/* no hpd */
+		return PORT_NONE; /* no port for this pin */
 	}
 }
 
@@ -389,8 +391,9 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
 		if (!(BIT(i) & pin_mask))
 			continue;
 
-		is_dig_port = intel_hpd_pin_to_port(i, &port) &&
-			      dev_priv->hotplug.irq_port[port];
+		port = intel_hpd_pin_to_port(i);
+		is_dig_port = port != PORT_NONE &&
+			dev_priv->hotplug.irq_port[port];
 
 		if (is_dig_port) {
 			bool long_hpd = long_mask & BIT(i);