drm/i915: Fix the training pattern debug print

Currently we claim to use TPS7 when using TPS4. That is just
confusing, so let's fix the debug print.

And while we're touching this let's add the customary
encoder id/name as well.

v2: Add MISSING_CASE() (Manasi)
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114205046.8247-2-ville.syrjala@linux.intel.com

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

@@ -4037,18 +4037,35 @@ ivb_cpu_edp_set_signal_levels(struct intel_dp *intel_dp,
 	intel_de_posting_read(dev_priv, intel_dp->output_reg);
 }
 
+static char dp_training_pattern_name(u8 train_pat)
+{
+	switch (train_pat) {
+	case DP_TRAINING_PATTERN_1:
+	case DP_TRAINING_PATTERN_2:
+	case DP_TRAINING_PATTERN_3:
+		return '0' + train_pat;
+	case DP_TRAINING_PATTERN_4:
+		return '4';
+	default:
+		MISSING_CASE(train_pat);
+		return '?';
+	}
+}
+
 void
 intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
 				       const struct intel_crtc_state *crtc_state,
 				       u8 dp_train_pat)
 {
-	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	u8 train_pat = intel_dp_training_pattern_symbol(dp_train_pat);
 
-	if ((intel_dp_training_pattern_symbol(dp_train_pat)) !=
-	    DP_TRAINING_PATTERN_DISABLE)
+	if (train_pat != DP_TRAINING_PATTERN_DISABLE)
 		drm_dbg_kms(&dev_priv->drm,
-			    "Using DP training pattern TPS%d\n",
-			    intel_dp_training_pattern_symbol(dp_train_pat));
+			    "[ENCODER:%d:%s] Using DP training pattern TPS%c\n",
+			    encoder->base.base.id, encoder->base.name,
+			    dp_training_pattern_name(train_pat));
 
 	intel_dp->set_link_train(intel_dp, crtc_state, dp_train_pat);
 }