drm/edid: Introduce drm_hdmi_avi_infoframe_quant_range()

Pull the logic to populate the quantization range information
in the AVI infoframe into a small helper. We'll be adding a bit
more logic to it, and having it in a central place seems like a
good idea since it's based on the CEA-861 spec.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170111125725.8086-4-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/drm_edid.c

@@ -4292,6 +4292,32 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 }
 EXPORT_SYMBOL(drm_hdmi_avi_infoframe_from_display_mode);
 
+/**
+ * drm_hdmi_avi_infoframe_quant_range() - fill the HDMI AVI infoframe
+ *                                        quantization range information
+ * @frame: HDMI AVI infoframe
+ * @rgb_quant_range: RGB quantization range (Q)
+ * @rgb_quant_range_selectable: Sink support selectable RGB quantization range (QS)
+ */
+void
+drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
+				   enum hdmi_quantization_range rgb_quant_range,
+				   bool rgb_quant_range_selectable)
+{
+	/*
+	 * CEA-861:
+	 * "A Source shall not send a non-zero Q value that does not correspond
+	 *  to the default RGB Quantization Range for the transmitted Picture
+	 *  unless the Sink indicates support for the Q bit in a Video
+	 *  Capabilities Data Block."
+	 */
+	if (rgb_quant_range_selectable)
+		frame->quantization_range = rgb_quant_range;
+	else
+		frame->quantization_range = HDMI_QUANTIZATION_RANGE_DEFAULT;
+}
+EXPORT_SYMBOL(drm_hdmi_avi_infoframe_quant_range);
+
 static enum hdmi_3d_structure
 s3d_structure_from_display_mode(const struct drm_display_mode *mode)
 {

drivers/gpu/drm/i915/intel_hdmi.c

@@ -465,14 +465,11 @@ static void intel_hdmi_set_avi_infoframe(struct drm_encoder *encoder,
 		return;
 	}
 
-	if (intel_hdmi->rgb_quant_range_selectable) {
-		if (crtc_state->limited_color_range)
-			frame.avi.quantization_range =
-				HDMI_QUANTIZATION_RANGE_LIMITED;
-		else
-			frame.avi.quantization_range =
-				HDMI_QUANTIZATION_RANGE_FULL;
-	}
+	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
+					   crtc_state->limited_color_range ?
+					   HDMI_QUANTIZATION_RANGE_LIMITED :
+					   HDMI_QUANTIZATION_RANGE_FULL,
+					   intel_hdmi->rgb_quant_range_selectable);
 
 	intel_write_infoframe(encoder, crtc_state, &frame);
 }

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -356,15 +356,11 @@ static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
 		return;
 	}
 
-	if (vc4_encoder->rgb_range_selectable) {
-		if (vc4_encoder->limited_rgb_range) {
-			frame.avi.quantization_range =
-				HDMI_QUANTIZATION_RANGE_LIMITED;
-		} else {
-			frame.avi.quantization_range =
-				HDMI_QUANTIZATION_RANGE_FULL;
-		}
-	}
+	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
+					   vc4_encoder->limited_rgb_range ?
+					   HDMI_QUANTIZATION_RANGE_LIMITED :
+					   HDMI_QUANTIZATION_RANGE_FULL,
+					   vc4_encoder->rgb_range_selectable);
 
 	vc4_hdmi_write_infoframe(encoder, &frame);
 }

include/drm/drm_edid.h

@@ -345,6 +345,10 @@ drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 int
 drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,
 					    const struct drm_display_mode *mode);
+void
+drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame,
+				   enum hdmi_quantization_range rgb_quant_range,
+				   bool rgb_quant_range_selectable);
 
 /**
  * drm_eld_mnl - Get ELD monitor name length in bytes.