drm/i915: Fix HDMI 12bpc and pixel repeat clock readout for DDI platforms

Take the HDMI 12bpc mode and pixel repeat into account when extracting
the dotclock from the hardware on DDI platforms.

Tested on HSW only.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-and-tested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ddi.c

@@ -1027,6 +1027,26 @@ static int skl_calc_wrpll_link(struct drm_i915_private *dev_priv,
 	return dco_freq / (p0 * p1 * p2 * 5);
 }
 
+static void ddi_dotclock_get(struct intel_crtc_state *pipe_config)
+{
+	int dotclock;
+
+	if (pipe_config->has_pch_encoder)
+		dotclock = intel_dotclock_calculate(pipe_config->port_clock,
+						    &pipe_config->fdi_m_n);
+	else if (pipe_config->has_dp_encoder)
+		dotclock = intel_dotclock_calculate(pipe_config->port_clock,
+						    &pipe_config->dp_m_n);
+	else if (pipe_config->has_hdmi_sink && pipe_config->pipe_bpp == 36)
+		dotclock = pipe_config->port_clock * 2 / 3;
+	else
+		dotclock = pipe_config->port_clock;
+
+	if (pipe_config->pixel_multiplier)
+		dotclock /= pipe_config->pixel_multiplier;
+
+	pipe_config->base.adjusted_mode.crtc_clock = dotclock;
+}
 
 static void skl_ddi_clock_get(struct intel_encoder *encoder,
 				struct intel_crtc_state *pipe_config)
@@ -1073,12 +1093,7 @@ static void skl_ddi_clock_get(struct intel_encoder *encoder,
 
 	pipe_config->port_clock = link_clock;
 
-	if (pipe_config->has_dp_encoder)
-		pipe_config->base.adjusted_mode.crtc_clock =
-			intel_dotclock_calculate(pipe_config->port_clock,
-						 &pipe_config->dp_m_n);
-	else
-		pipe_config->base.adjusted_mode.crtc_clock = pipe_config->port_clock;
+	ddi_dotclock_get(pipe_config);
 }
 
 static void hsw_ddi_clock_get(struct intel_encoder *encoder,
@@ -1125,16 +1140,7 @@ static void hsw_ddi_clock_get(struct intel_encoder *encoder,
 
 	pipe_config->port_clock = link_clock * 2;
 
-	if (pipe_config->has_pch_encoder)
-		pipe_config->base.adjusted_mode.crtc_clock =
-			intel_dotclock_calculate(pipe_config->port_clock,
-						 &pipe_config->fdi_m_n);
-	else if (pipe_config->has_dp_encoder)
-		pipe_config->base.adjusted_mode.crtc_clock =
-			intel_dotclock_calculate(pipe_config->port_clock,
-						 &pipe_config->dp_m_n);
-	else
-		pipe_config->base.adjusted_mode.crtc_clock = pipe_config->port_clock;
+	ddi_dotclock_get(pipe_config);
 }
 
 static int bxt_calc_pll_link(struct drm_i915_private *dev_priv,
@@ -1169,16 +1175,9 @@ static void bxt_ddi_clock_get(struct intel_encoder *encoder,
 	enum port port = intel_ddi_get_encoder_port(encoder);
 	uint32_t dpll = port;
 
-	pipe_config->port_clock =
-		bxt_calc_pll_link(dev_priv, dpll);
+	pipe_config->port_clock = bxt_calc_pll_link(dev_priv, dpll);
 
-	if (pipe_config->has_dp_encoder)
-		pipe_config->base.adjusted_mode.crtc_clock =
-			intel_dotclock_calculate(pipe_config->port_clock,
-							&pipe_config->dp_m_n);
-	else
-		pipe_config->base.adjusted_mode.crtc_clock =
-							pipe_config->port_clock;
+	ddi_dotclock_get(pipe_config);
 }
 
 void intel_ddi_clock_get(struct intel_encoder *encoder,