drm/i915/icl: Get DSI transcoder for a given port

This patch adds a helper function to retrieve DSI
transcoder for a given DSI port using newly defined
enum names for DSI transcoders.
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f88ff26fa10c68e37b7838bb7c8573c881474e73.1539613303.git.jani.nikula@intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -27,6 +27,14 @@
 
 #include "intel_dsi.h"
 
+static enum transcoder __attribute__((unused)) dsi_port_to_transcoder(enum port port)
+{
+	if (port == PORT_A)
+		return TRANSCODER_DSI_0;
+	else
+		return TRANSCODER_DSI_1;
+}
+
 static void dsi_program_swing_and_deemphasis(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);

drivers/gpu/drm/i915/intel_display.h

@@ -61,8 +61,10 @@ enum transcoder {
 	TRANSCODER_B,
 	TRANSCODER_C,
 	TRANSCODER_EDP,
-	TRANSCODER_DSI_A,
-	TRANSCODER_DSI_C,
+	TRANSCODER_DSI_0,
+	TRANSCODER_DSI_1,
+	TRANSCODER_DSI_A = TRANSCODER_DSI_0,	/* legacy DSI */
+	TRANSCODER_DSI_C = TRANSCODER_DSI_1,	/* legacy DSI */
 
 	I915_MAX_TRANSCODERS
 };