drm/i915/dg2: Classify DG2 PHY types

Although the bspec labels four of DG2's outputs as "combo PHY," the
underlying PHYs in both cases are actually Synopsys PHYs that are
programmed completely differently than the traditional Intel "combo" PHY
units.  As such, we don't want intel_phy_is_combo to take us down legacy
programming paths, so just return false from it on DG2.  Instead add a
new intel_phy_is_snps() that will return true for all DG2 PHYs.

Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714031540.3539704-46-matthew.d.roper@intel.com

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

@@ -3694,6 +3694,13 @@ bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy)
 {
 	if (phy == PHY_NONE)
 		return false;
+	else if (IS_DG2(dev_priv))
+		/*
+		 * DG2 outputs labelled as "combo PHY" in the bspec use
+		 * SNPS PHYs with completely different programming,
+		 * hence we always return false here.
+		 */
+		return false;
 	else if (IS_ALDERLAKE_S(dev_priv))
 		return phy <= PHY_E;
 	else if (IS_DG1(dev_priv) || IS_ROCKETLAKE(dev_priv))
@@ -3708,7 +3715,10 @@ bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy)
 
 bool intel_phy_is_tc(struct drm_i915_private *dev_priv, enum phy phy)
 {
-	if (IS_ALDERLAKE_P(dev_priv))
+	if (IS_DG2(dev_priv))
+		/* DG2's "TC1" output uses a SNPS PHY */
+		return false;
+	else if (IS_ALDERLAKE_P(dev_priv))
 		return phy >= PHY_F && phy <= PHY_I;
 	else if (IS_TIGERLAKE(dev_priv))
 		return phy >= PHY_D && phy <= PHY_I;
@@ -3718,6 +3728,20 @@ bool intel_phy_is_tc(struct drm_i915_private *dev_priv, enum phy phy)
 		return false;
 }
 
+bool intel_phy_is_snps(struct drm_i915_private *dev_priv, enum phy phy)
+{
+	if (phy == PHY_NONE)
+		return false;
+	else if (IS_DG2(dev_priv))
+		/*
+		 * All four "combo" ports and the TC1 port (PHY E) use
+		 * Synopsis PHYs.
+		 */
+		return phy <= PHY_E;
+
+	return false;
+}
+
 enum phy intel_port_to_phy(struct drm_i915_private *i915, enum port port)
 {
 	if (DISPLAY_VER(i915) >= 13 && port >= PORT_D_XELPD)

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

@@ -561,6 +561,7 @@ struct drm_display_mode *
 intel_encoder_current_mode(struct intel_encoder *encoder);
 bool intel_phy_is_combo(struct drm_i915_private *dev_priv, enum phy phy);
 bool intel_phy_is_tc(struct drm_i915_private *dev_priv, enum phy phy);
+bool intel_phy_is_snps(struct drm_i915_private *dev_priv, enum phy phy);
 enum tc_port intel_port_to_tc(struct drm_i915_private *dev_priv,
 			      enum port port);
 int intel_get_pipe_from_crtc_id_ioctl(struct drm_device *dev, void *data,