drm/i915/icl: Cleanup combo PHY aux power well handlers

Now that the combo PHY aux power well handlers are used exclusively on
Icelake, we can drop a bunch of the extra tests.

v2: Don't try to use intel_uncore_rmw for register updates yet; there's
    pending display uncore patches that need to land first.  (Lucas)

v3: Drop the combo phy assertion.  It was backward before, but doesn't
    seem terribly necessary.  I'm keeping the IS_ICELAKE assertion
    though since we often copy/paste/modify the power well tables when
    defining new platforms and it's too easy to cargo cult the
    ICL-specific handling to new platforms that shouldn't use it.
    (Lucas)

v4: Fix build; forgot to commit all the changes.  (CI)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191213010600.701315-1-matthew.d.roper@intel.comReviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

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

@@ -418,7 +418,8 @@ icl_combo_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
 	int pw_idx = power_well->desc->hsw.idx;
 	enum phy phy = ICL_AUX_PW_TO_PHY(pw_idx);
 	u32 val;
-	int wa_idx_max;
+
+	WARN_ON(!IS_ICELAKE(dev_priv));
 
 	val = I915_READ(regs->driver);
 	I915_WRITE(regs->driver, val | HSW_PWR_WELL_CTL_REQ(pw_idx));
@@ -430,14 +431,8 @@ icl_combo_phy_aux_power_well_enable(struct drm_i915_private *dev_priv,
 
 	hsw_wait_for_power_well_enable(dev_priv, power_well);
 
-	/* Display WA #1178: icl, tgl */
-	if (IS_TIGERLAKE(dev_priv))
-		wa_idx_max = ICL_PW_CTL_IDX_AUX_C;
-	else
-		wa_idx_max = ICL_PW_CTL_IDX_AUX_B;
-
-	if (!IS_ELKHARTLAKE(dev_priv) &&
-	    pw_idx >= ICL_PW_CTL_IDX_AUX_A && pw_idx <= wa_idx_max &&
+	/* Display WA #1178: icl */
+	if (pw_idx >= ICL_PW_CTL_IDX_AUX_A && pw_idx <= ICL_PW_CTL_IDX_AUX_B &&
 	    !intel_bios_is_port_edp(dev_priv, (enum port)phy)) {
 		val = I915_READ(ICL_AUX_ANAOVRD1(pw_idx));
 		val |= ICL_AUX_ANAOVRD1_ENABLE | ICL_AUX_ANAOVRD1_LDO_BYPASS;
@@ -454,10 +449,10 @@ icl_combo_phy_aux_power_well_disable(struct drm_i915_private *dev_priv,
 	enum phy phy = ICL_AUX_PW_TO_PHY(pw_idx);
 	u32 val;
 
-	if (INTEL_GEN(dev_priv) < 12) {
+	WARN_ON(!IS_ICELAKE(dev_priv));
+
 	val = I915_READ(ICL_PORT_CL_DW12(phy));
 	I915_WRITE(ICL_PORT_CL_DW12(phy), val & ~ICL_LANE_ENABLE_AUX);
-	}
 
 	val = I915_READ(regs->driver);
 	I915_WRITE(regs->driver, val & ~HSW_PWR_WELL_CTL_REQ(pw_idx));