drm/i915/dg2: Add cdclk table and reference clock

Note that DG2 only has a single possible refclk frequency (38.4 MHz).

v2:
 - Drop two now-unused cdclk entries

Bspec: 54034
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721223043.834562-12-matthew.d.roper@intel.com

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

@@ -1290,6 +1290,16 @@ static const struct intel_cdclk_vals adlp_cdclk_table[] = {
 	{}
 };
 
+static const struct intel_cdclk_vals dg2_cdclk_table[] = {
+	{ .refclk = 38400, .cdclk = 172800, .divider = 2, .ratio =  9 },
+	{ .refclk = 38400, .cdclk = 192000, .divider = 2, .ratio = 10 },
+	{ .refclk = 38400, .cdclk = 307200, .divider = 2, .ratio = 16 },
+	{ .refclk = 38400, .cdclk = 326400, .divider = 4, .ratio = 34 },
+	{ .refclk = 38400, .cdclk = 556800, .divider = 2, .ratio = 29 },
+	{ .refclk = 38400, .cdclk = 652800, .divider = 2, .ratio = 34 },
+	{}
+};
+
 static int bxt_calc_cdclk(struct drm_i915_private *dev_priv, int min_cdclk)
 {
 	const struct intel_cdclk_vals *table = dev_priv->cdclk.table;
@@ -1408,7 +1418,9 @@ static void bxt_de_pll_readout(struct drm_i915_private *dev_priv,
 {
 	u32 val, ratio;
 
-	if (DISPLAY_VER(dev_priv) >= 11)
+	if (IS_DG2(dev_priv))
+		cdclk_config->ref = 38400;
+	else if (DISPLAY_VER(dev_priv) >= 11)
 		icl_readout_refclk(dev_priv, cdclk_config);
 	else if (IS_CANNONLAKE(dev_priv))
 		cnl_readout_refclk(dev_priv, cdclk_config);
@@ -2873,7 +2885,13 @@ u32 intel_read_rawclk(struct drm_i915_private *dev_priv)
  */
 void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
 {
-	if (IS_ALDERLAKE_P(dev_priv)) {
+	if (IS_DG2(dev_priv)) {
+		dev_priv->display.set_cdclk = bxt_set_cdclk;
+		dev_priv->display.bw_calc_min_cdclk = skl_bw_calc_min_cdclk;
+		dev_priv->display.modeset_calc_cdclk = bxt_modeset_calc_cdclk;
+		dev_priv->display.calc_voltage_level = tgl_calc_voltage_level;
+		dev_priv->cdclk.table = dg2_cdclk_table;
+	} else if (IS_ALDERLAKE_P(dev_priv)) {
 		dev_priv->display.set_cdclk = bxt_set_cdclk;
 		dev_priv->display.bw_calc_min_cdclk = skl_bw_calc_min_cdclk;
 		dev_priv->display.modeset_calc_cdclk = bxt_modeset_calc_cdclk;