drm/i915: start adding dp mst audio

This patch adds support for DP MST audio in i915.

Enable audio codec when DP MST is enabled if has_audio flag is set.
Disable audio codec when DP MST is disabled if has_audio flag is set.

Another separated patches to support DP MST audio will be implemented
in audio driver.

Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449036584-105393-2-git-send-email-libin.yang@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 1fad19e..f00a3c9 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -3114,6 +3114,19 @@
 	I915_WRITE(FDI_RX_CTL(PIPE_A), val);
 }
 
+bool intel_ddi_is_audio_enabled(struct drm_i915_private *dev_priv,
+				 struct intel_crtc *intel_crtc)
+{
+	u32 temp;
+
+	if (intel_display_power_is_enabled(dev_priv, POWER_DOMAIN_AUDIO)) {
+		temp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
+		if (temp & AUDIO_OUTPUT_ENABLE(intel_crtc->pipe))
+			return true;
+	}
+	return false;
+}
+
 void intel_ddi_get_config(struct intel_encoder *encoder,
 			  struct intel_crtc_state *pipe_config)
 {
@@ -3174,11 +3187,8 @@
 		break;
 	}
 
-	if (intel_display_power_is_enabled(dev_priv, POWER_DOMAIN_AUDIO)) {
-		temp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
-		if (temp & AUDIO_OUTPUT_ENABLE(intel_crtc->pipe))
-			pipe_config->has_audio = true;
-	}
+	pipe_config->has_audio =
+		intel_ddi_is_audio_enabled(dev_priv, intel_crtc);
 
 	if (encoder->type == INTEL_OUTPUT_EDP && dev_priv->vbt.edp_bpp &&
 	    pipe_config->pipe_bpp > dev_priv->vbt.edp_bpp) {