drm/i915/dg2: Support 4k@30 on HDMI

This patch adds a fix to support 297MHz of dot clock by calculating
the pll values using synopsis algorithm.
This will help to support 4k@30 mode for HDMI monitors on DG2.

v2: As per the algorithm, set MPLLB VCO range control bits to 3,
in register SNPS_PHY_MPLLB_DIV for 297Mhz. (Matt)

v3: Fix typo. (Ankit)
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220525080401.1253511-1-ankit.k.nautiyal@intel.com

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

@@ -517,6 +517,37 @@ static const struct intel_mpllb_state dg2_hdmi_148_5 = {
 		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
 };
 
+/* values in the below table are calculted using the algo */
+static const struct intel_mpllb_state dg2_hdmi_297 = {
+	.clock = 297000,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 6) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 14) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_TX_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FREQ_VCO, 3),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 86) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 65535),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 26214) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 26214),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
+
 static const struct intel_mpllb_state dg2_hdmi_594 = {
 	.clock = 594000,
 	.ref_control =
@@ -551,6 +582,7 @@ static const struct intel_mpllb_state * const dg2_hdmi_tables[] = {
 	&dg2_hdmi_27_0,
 	&dg2_hdmi_74_25,
 	&dg2_hdmi_148_5,
+	&dg2_hdmi_297,
 	&dg2_hdmi_594,
 	NULL,
 };