[PATCH 3/5] drm/i915/ehl: Don't program PHY_MISC on EHL PHY C

[Matt Roper <matthew.d.roper@intel.com>]

Although EHL added a third combo PHY, no PHY_MISC register was added for
PHY C.  The bspec indicates that there's no need to program the "DE to
IO Comp Pwr Down" setting for this PHY that we usually need to set in
PHY_MISC.

Bspec: 33148
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
 .../gpu/drm/i915/display/intel_combo_phy.c    | 53 +++++++++++++------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_combo_phy.c b/drivers/gpu/drm/i915/display/intel_combo_phy.c
index 075bab2500eb..da590f1a998b 100644
--- a/drivers/gpu/drm/i915/display/intel_combo_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_combo_phy.c
@@ -183,9 +183,13 @@ static void cnl_combo_phys_uninit(struct drm_i915_private *dev_priv)
 static bool icl_combo_phy_enabled(struct drm_i915_private *dev_priv,
 				  enum port port)
 {
-	return !(I915_READ(ICL_PHY_MISC(port)) &
-		 ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN) &&
-		(I915_READ(ICL_PORT_COMP_DW0(port)) & COMP_INIT);
+	/* The PHY C added by EHL has no PHY_MISC register */
+	if (port == PORT_C)
+		return I915_READ(ICL_PORT_COMP_DW0(port)) & COMP_INIT;
+	else
+		return !(I915_READ(ICL_PHY_MISC(port)) &
+			 ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN) &&
+			(I915_READ(ICL_PORT_COMP_DW0(port)) & COMP_INIT);
 }
 
 static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
@@ -300,18 +304,26 @@ static void icl_combo_phys_init(struct drm_i915_private *dev_priv)
 		}
 
 		/*
-		 * EHL's combo PHY A can be hooked up to either an external
-		 * display (via DDI-D) or an internal display (via DDI-A or
-		 * the DSI DPHY).  This is a motherboard design decision that
-		 * can't be changed on the fly, so initialize the PHY's mux
-		 * based on whether our VBT indicates the presence of any
-		 * "internal" child devices.
+		 * Although EHL adds a combo PHY C, there's no PHY_MISC
+		 * register for it and no need to program the
+		 * DE_IO_COMP_PWR_DOWN setting on PHY C.
 		 */
-		val = I915_READ(ICL_PHY_MISC(port));
-		if (IS_ELKHARTLAKE(dev_priv) && port == PORT_A)
-			val = ehl_combo_phy_a_mux(dev_priv, val);
-		val &= ~ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
-		I915_WRITE(ICL_PHY_MISC(port), val);
+		if (port != PORT_C) {
+			/*
+			 * EHL's combo PHY A can be hooked up to either an
+			 * external display (via DDI-D) or an internal display
+			 * (via DDI-A or the DSI DPHY).  This is a motherboard
+			 * design decision that can't be changed on the fly, so
+			 * initialize the PHY's mux based on whether our VBT
+			 * indicates the presence of any "internal" child
+			 * devices.
+			 */
+			val = I915_READ(ICL_PHY_MISC(port));
+			if (IS_ELKHARTLAKE(dev_priv) && port == PORT_A)
+				val = ehl_combo_phy_a_mux(dev_priv, val);
+			val &= ~ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
+			I915_WRITE(ICL_PHY_MISC(port), val);
+		}
 
 		cnl_set_procmon_ref_values(dev_priv, port);
 
@@ -343,9 +355,16 @@ static void icl_combo_phys_uninit(struct drm_i915_private *dev_priv)
 			DRM_WARN("Port %c combo PHY HW state changed unexpectedly\n",
 				 port_name(port));
 
-		val = I915_READ(ICL_PHY_MISC(port));
-		val |= ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
-		I915_WRITE(ICL_PHY_MISC(port), val);
+		/*
+		 * Although EHL adds a combo PHY C, there's no PHY_MISC
+		 * register for it and no need to program the
+		 * DE_IO_COMP_PWR_DOWN setting on PHY C.
+		 */
+		if (port != PORT_C) {
+			val = I915_READ(ICL_PHY_MISC(port));
+			val |= ICL_PHY_MISC_DE_IO_COMP_PWR_DOWN;
+			I915_WRITE(ICL_PHY_MISC(port), val);
+		}
 
 		val = I915_READ(ICL_PORT_COMP_DW0(port));
 		val &= ~COMP_INIT;
-- 
2.17.2

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