drm/i915/bxt: eDP low vswing support

Adding voltage swing table for edp to support low vswings.

v2: Rebased.

Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 9e640eafc50d2e52f7fe2c2ded012e7dab01d4bc..205f61832d4af37fd2551cbf1f2843a6725a79f9 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -256,9 +256,6 @@ struct bxt_ddi_buf_trans {
        bool default_index; /* true if the entry represents default value */
 };
 
-/* BSpec does not define separate vswing/pre-emphasis values for eDP.
- * Using DP values for eDP as well.
- */
 static const struct bxt_ddi_buf_trans bxt_ddi_translations_dp[] = {
                                        /* Idx  NT mV diff      db  */
        { 52,  0x9A, 0, 128, true  },   /* 0:   400             0   */
@@ -273,6 +270,20 @@ static const struct bxt_ddi_buf_trans bxt_ddi_translations_dp[] = {
        { 154, 0x9A, 1, 128, false },   /* 9:   1200            0   */
 };
 
+static const struct bxt_ddi_buf_trans bxt_ddi_translations_edp[] = {
+                                       /* Idx  NT mV diff      db  */
+       { 26, 0, 0, 128, false },       /* 0:   200             0   */
+       { 38, 0, 0, 112, false },       /* 1:   200             1.5 */
+       { 48, 0, 0, 96,  false },       /* 2:   200             4   */
+       { 54, 0, 0, 69,  false },       /* 3:   200             6   */
+       { 32, 0, 0, 128, false },       /* 4:   250             0   */
+       { 48, 0, 0, 104, false },       /* 5:   250             1.5 */
+       { 54, 0, 0, 85,  false },       /* 6:   250             4   */
+       { 43, 0, 0, 128, false },       /* 7:   300             0   */
+       { 54, 0, 0, 101, false },       /* 8:   300             1.5 */
+       { 48, 0, 0, 128, false },       /* 9:   300             0   */
+};
+
 /* BSpec has 2 recommended values - entries 0 and 8.
  * Using the entry with higher vswing.
  */
@@ -2112,7 +2123,11 @@ static void bxt_ddi_vswing_sequence(struct drm_device *dev, u32 level,
        u32 n_entries, i;
        uint32_t val;
 
-       if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
+       if (type == INTEL_OUTPUT_EDP && dev_priv->edp_low_vswing) {
+               n_entries = ARRAY_SIZE(bxt_ddi_translations_edp);
+               ddi_translations = bxt_ddi_translations_edp;
+       } else if (type == INTEL_OUTPUT_DISPLAYPORT
+                       || type == INTEL_OUTPUT_EDP) {
                n_entries = ARRAY_SIZE(bxt_ddi_translations_dp);
                ddi_translations = bxt_ddi_translations_dp;
        } else if (type == INTEL_OUTPUT_HDMI) {