drm/i915: Clean up the CPT DP .get_hw_state() port readout

Define a TRANS_DP_PIPE_TO_PORT() to make the CPT DP .get_hw_state()
pipe readout neater.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -6440,6 +6440,7 @@ enum skl_disp_power_wells {
 #define  TRANS_DP_PORT_SEL_D	(2<<29)
 #define  TRANS_DP_PORT_SEL_NONE	(3<<29)
 #define  TRANS_DP_PORT_SEL_MASK	(3<<29)
+#define  TRANS_DP_PIPE_TO_PORT(val)	((((val) & TRANS_DP_PORT_SEL_MASK) >> 29) + PORT_B)
 #define  TRANS_DP_AUDIO_ONLY	(1<<26)
 #define  TRANS_DP_ENH_FRAMING	(1<<18)
 #define  TRANS_DP_8BPC		(0<<9)

drivers/gpu/drm/i915/intel_dp.c

@@ -2186,28 +2186,12 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
 	if (IS_GEN7(dev) && port == PORT_A) {
 		*pipe = PORT_TO_PIPE_CPT(tmp);
 	} else if (HAS_PCH_CPT(dev) && port != PORT_A) {
-		u32 trans_sel;
-		u32 trans_dp;
-		int i;
-
-		switch (intel_dp->output_reg) {
-		case PCH_DP_B:
-			trans_sel = TRANS_DP_PORT_SEL_B;
-			break;
-		case PCH_DP_C:
-			trans_sel = TRANS_DP_PORT_SEL_C;
-			break;
-		case PCH_DP_D:
-			trans_sel = TRANS_DP_PORT_SEL_D;
-			break;
-		default:
-			return true;
-		}
+		enum pipe p;
 
-		for_each_pipe(dev_priv, i) {
-			trans_dp = I915_READ(TRANS_DP_CTL(i));
-			if ((trans_dp & TRANS_DP_PORT_SEL_MASK) == trans_sel) {
-				*pipe = i;
+		for_each_pipe(dev_priv, p) {
+			u32 trans_dp = I915_READ(TRANS_DP_CTL(p));
+			if (TRANS_DP_PIPE_TO_PORT(trans_dp) == port) {
+				*pipe = p;
 				return true;
 			}
 		}