drm/i915/mtl: Add voltage swing sequence for C20

DP1.4 and DP20 voltage swing sequence for C20 phy.

Bspec: 65449, 67636, 67610
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428095433.4109054-6-mika.kahola@intel.com

drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h

@@ -212,6 +212,10 @@
 #define   C20_MULTIPLIER_MASK		REG_GENMASK(11, 0)
 #define   C20_PHY_USE_MPLLB		REG_BIT(7)
 
+/* C20 Phy VSwing Masks */
+#define C20_PHY_VSWING_PREEMPH_MASK	REG_GENMASK8(5, 0)
+#define C20_PHY_VSWING_PREEMPH(val)	REG_FIELD_PREP8(C20_PHY_VSWING_PREEMPH_MASK, val)
+
 #define RAWLANEAONX_DIG_TX_MPLLB_CAL_DONE_BANK(idx) (0x303D + (idx))
 
 #endif /* __INTEL_CX0_REG_DEFS_H__ */

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

@@ -9,6 +9,7 @@
 #include "intel_de.h"
 #include "intel_display_types.h"
 #include "intel_dp.h"
+#include "intel_cx0_phy.h"
 
 /* HDMI/DVI modes ignore everything but the last 2 items. So we share
  * them for both DP and FDI transports, allowing those ports to
@@ -1048,12 +1049,52 @@ static const union intel_ddi_buf_trans_entry _mtl_c10_trans_dp14[] = {
 	{ .snps = { 62, 0, 0  } },      /* preset 9 */
 };
 
-static const struct intel_ddi_buf_trans mtl_cx0c10_trans = {
+static const struct intel_ddi_buf_trans mtl_cx0_trans = {
 	.entries = _mtl_c10_trans_dp14,
 	.num_entries = ARRAY_SIZE(_mtl_c10_trans_dp14),
 	.hdmi_default_entry = ARRAY_SIZE(_mtl_c10_trans_dp14) - 1,
 };
 
+/* DP2.0 */
+static const union intel_ddi_buf_trans_entry _mtl_c20_trans_uhbr[] = {
+	{ .snps = { 48, 0, 0 } },       /* preset 0 */
+	{ .snps = { 43, 0, 5 } },       /* preset 1 */
+	{ .snps = { 40, 0, 8 } },       /* preset 2 */
+	{ .snps = { 37, 0, 11 } },      /* preset 3 */
+	{ .snps = { 33, 0, 15 } },      /* preset 4 */
+	{ .snps = { 46, 2, 0 } },       /* preset 5 */
+	{ .snps = { 42, 2, 4 } },       /* preset 6 */
+	{ .snps = { 38, 2, 8 } },       /* preset 7 */
+	{ .snps = { 35, 2, 11 } },      /* preset 8 */
+	{ .snps = { 33, 2, 13 } },      /* preset 9 */
+	{ .snps = { 44, 4, 0 } },       /* preset 10 */
+	{ .snps = { 40, 4, 4 } },       /* preset 11 */
+	{ .snps = { 37, 4, 7 } },       /* preset 12 */
+	{ .snps = { 33, 4, 11 } },      /* preset 13 */
+	{ .snps = { 40, 8, 0 } },	/* preset 14 */
+	{ .snps = { 28, 2, 2 } },	/* preset 15 */
+};
+
+/* HDMI2.0 */
+static const union intel_ddi_buf_trans_entry _mtl_c20_trans_hdmi[] = {
+	{ .snps = { 48, 0, 0 } },       /* preset 0 */
+	{ .snps = { 38, 4, 6 } },       /* preset 1 */
+	{ .snps = { 36, 4, 8 } },       /* preset 2 */
+	{ .snps = { 34, 4, 10 } },      /* preset 3 */
+	{ .snps = { 32, 4, 12 } },      /* preset 4 */
+};
+
+static const struct intel_ddi_buf_trans mtl_c20_trans_hdmi = {
+	.entries = _mtl_c20_trans_hdmi,
+	.num_entries = ARRAY_SIZE(_mtl_c20_trans_hdmi),
+	.hdmi_default_entry = 0,
+};
+
+static const struct intel_ddi_buf_trans mtl_c20_trans_uhbr = {
+	.entries = _mtl_c20_trans_uhbr,
+	.num_entries = ARRAY_SIZE(_mtl_c20_trans_uhbr),
+};
+
 bool is_hobl_buf_trans(const struct intel_ddi_buf_trans *table)
 {
 	return table == &tgl_combo_phy_trans_edp_hbr2_hobl;
@@ -1630,7 +1671,15 @@ mtl_get_cx0_buf_trans(struct intel_encoder *encoder,
 		      const struct intel_crtc_state *crtc_state,
 		      int *n_entries)
 {
-	return intel_get_buf_trans(&mtl_cx0c10_trans, n_entries);
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+	enum phy phy = intel_port_to_phy(i915, encoder->port);
+
+	if (intel_crtc_has_dp_encoder(crtc_state) && crtc_state->port_clock >= 1000000)
+		return intel_get_buf_trans(&mtl_c20_trans_uhbr, n_entries);
+	else if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI) && !(intel_is_c10phy(i915, phy)))
+		return intel_get_buf_trans(&mtl_c20_trans_hdmi, n_entries);
+	else
+		return intel_get_buf_trans(&mtl_cx0_trans, n_entries);
 }
 
 void intel_ddi_buf_trans_init(struct intel_encoder *encoder)