drm/i915/dp: Add helper to get sink_format

Common function to get the sink format for a given mode for DP.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230427125605.487769-6-ankit.k.nautiyal@intel.com

drivers/gpu/drm/i915/display/intel_dp.c

@@ -954,17 +954,25 @@ static int intel_dp_output_bpp(enum intel_output_format output_format, int bpp)
 	return bpp;
 }
 
+static enum intel_output_format
+intel_dp_sink_format(struct intel_connector *connector,
+		     const struct drm_display_mode *mode)
+{
+	const struct drm_display_info *info = &connector->base.display_info;
+
+	if (drm_mode_is_420_only(info, mode))
+		return INTEL_OUTPUT_FORMAT_YCBCR420;
+
+	return INTEL_OUTPUT_FORMAT_RGB;
+}
+
 static int
 intel_dp_mode_min_output_bpp(struct intel_connector *connector,
 			     const struct drm_display_mode *mode)
 {
-	const struct drm_display_info *info = &connector->base.display_info;
 	enum intel_output_format output_format, sink_format;
 
-	if (drm_mode_is_420_only(info, mode))
-		sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
-	else
-		sink_format = INTEL_OUTPUT_FORMAT_RGB;
+	sink_format = intel_dp_sink_format(connector, mode);
 
 	output_format = intel_dp_output_format(connector, sink_format);
 
@@ -1036,7 +1044,6 @@ intel_dp_mode_valid_downstream(struct intel_connector *connector,
 	struct intel_dp *intel_dp = intel_attached_dp(connector);
 	const struct drm_display_info *info = &connector->base.display_info;
 	enum drm_mode_status status;
-	bool ycbcr_420_only;
 	enum intel_output_format sink_format;
 
 	/* If PCON supports FRL MODE, check FRL bandwidth constraints */
@@ -1062,12 +1069,7 @@ intel_dp_mode_valid_downstream(struct intel_connector *connector,
 	    target_clock > intel_dp->dfp.max_dotclock)
 		return MODE_CLOCK_HIGH;
 
-	ycbcr_420_only = drm_mode_is_420_only(info, mode);
-
-	if (ycbcr_420_only)
-		sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
-	else
-		sink_format = INTEL_OUTPUT_FORMAT_RGB;
+	sink_format = intel_dp_sink_format(connector, mode);
 
 	/* Assume 8bpc for the DP++/HDMI/DVI TMDS clock check */
 	status = intel_dp_tmds_clock_valid(intel_dp, target_clock,
@@ -2188,10 +2190,8 @@ intel_dp_compute_output_format(struct intel_encoder *encoder,
 		drm_dbg_kms(&i915->drm,
 			    "YCbCr 4:2:0 mode but YCbCr 4:2:0 output not possible. Falling back to RGB.\n");
 		crtc_state->sink_format = INTEL_OUTPUT_FORMAT_RGB;
-	} else if (ycbcr_420_only) {
-		crtc_state->sink_format = INTEL_OUTPUT_FORMAT_YCBCR420;
 	} else {
-		crtc_state->sink_format = INTEL_OUTPUT_FORMAT_RGB;
+		crtc_state->sink_format = intel_dp_sink_format(connector, adjusted_mode);
 	}
 
 	crtc_state->output_format = intel_dp_output_format(connector, crtc_state->sink_format);