drm/i915/rkl: RKL only uses PHY_MISC for PHY's A and B

Since the number of platforms with this restriction are growing, let's
separate out the platform logic into a has_phy_misc() function.

Bspec: 50107
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200504225227.464666-11-matthew.d.roper@intel.com

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

@@ -181,11 +181,25 @@ static void cnl_combo_phys_uninit(struct drm_i915_private *dev_priv)
 	intel_de_write(dev_priv, CHICKEN_MISC_2, val);
 }
 
+static bool has_phy_misc(struct drm_i915_private *i915, enum phy phy)
+{
+	/*
+	 * Some platforms only expect PHY_MISC to be programmed for PHY-A and
+	 * PHY-B and may not even have instances of the register for the
+	 * other combo PHY's.
+	 */
+	if (IS_ELKHARTLAKE(i915) ||
+	    IS_ROCKETLAKE(i915))
+		return phy < PHY_C;
+
+	return true;
+}
+
 static bool icl_combo_phy_enabled(struct drm_i915_private *dev_priv,
 				  enum phy phy)
 {
 	/* The PHY C added by EHL has no PHY_MISC register */
-	if (IS_ELKHARTLAKE(dev_priv) && phy == PHY_C)
+	if (!has_phy_misc(dev_priv, phy))
 		return intel_de_read(dev_priv, ICL_PORT_COMP_DW0(phy)) & COMP_INIT;
 	else
 		return !(intel_de_read(dev_priv, ICL_PHY_MISC(phy)) &
@@ -317,12 +331,7 @@ static void icl_combo_phys_init(struct drm_i915_private *dev_priv)
 			continue;
 		}
 
-		/*
-		 * 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 (IS_ELKHARTLAKE(dev_priv) && phy == PHY_C)
+		if (!has_phy_misc(dev_priv, phy))
 			goto skip_phy_misc;
 
 		/*
@@ -376,12 +385,7 @@ static void icl_combo_phys_uninit(struct drm_i915_private *dev_priv)
 				 "Combo PHY %c HW state changed unexpectedly\n",
 				 phy_name(phy));
 
-		/*
-		 * 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 (IS_ELKHARTLAKE(dev_priv) && phy == PHY_C)
+		if (!has_phy_misc(dev_priv, phy))
 			goto skip_phy_misc;
 
 		val = intel_de_read(dev_priv, ICL_PHY_MISC(phy));