drm/i915/icl: split pll enable in three steps

Create separate functions to 1) enable power, 2) write pll config, and
3) enable pll. Doing this it makes it easier to share the functions for
the different PLL types by passing the right arguments.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190309035727.25389-3-lucas.demarchi@intel.com

drivers/gpu/drm/i915/intel_dpll_mgr.c

@@ -3116,11 +3116,10 @@ static void icl_mg_pll_write(struct drm_i915_private *dev_priv,
 	POSTING_READ(MG_PLL_TDC_COLDST_BIAS(tc_port));
 }
 
-static void icl_pll_enable(struct drm_i915_private *dev_priv,
-			   struct intel_shared_dpll *pll,
-			   i915_reg_t enable_reg)
+static void icl_pll_power_enable(struct drm_i915_private *dev_priv,
+				 struct intel_shared_dpll *pll,
+				 i915_reg_t enable_reg)
 {
-	const enum intel_dpll_id id = pll->info->id;
 	u32 val;
 
 	val = I915_READ(enable_reg);
@@ -3133,36 +3132,43 @@ static void icl_pll_enable(struct drm_i915_private *dev_priv,
 	 */
 	if (intel_wait_for_register(dev_priv, enable_reg, PLL_POWER_STATE,
 				    PLL_POWER_STATE, 1))
-		DRM_ERROR("PLL %d Power not enabled\n", id);
-
-	if (intel_dpll_is_combophy(id) || id == DPLL_ID_ICL_TBTPLL)
-		icl_dpll_write(dev_priv, pll);
-	else
-		icl_mg_pll_write(dev_priv, pll);
+		DRM_ERROR("PLL %d Power not enabled\n", pll->info->id);
+}
 
-	/*
-	 * DVFS pre sequence would be here, but in our driver the cdclk code
-	 * paths should already be setting the appropriate voltage, hence we do
-	 * nothign here.
-	 */
+static void icl_pll_enable(struct drm_i915_private *dev_priv,
+			   struct intel_shared_dpll *pll,
+			   i915_reg_t enable_reg)
+{
+	u32 val;
 
 	val = I915_READ(enable_reg);
 	val |= PLL_ENABLE;
 	I915_WRITE(enable_reg, val);
 
+	/* Timeout is actually 600us. */
 	if (intel_wait_for_register(dev_priv, enable_reg, PLL_LOCK, PLL_LOCK,
-				    1)) /* 600us actually. */
-		DRM_ERROR("PLL %d not locked\n", id);
-
-	/* DVFS post sequence would be here. See the comment above. */
+				    1))
+		DRM_ERROR("PLL %d not locked\n", pll->info->id);
 }
 
 static void combo_pll_enable(struct drm_i915_private *dev_priv,
 			     struct intel_shared_dpll *pll)
 {
 	i915_reg_t enable_reg = icl_pll_id_to_enable_reg(pll->info->id);
 
+	icl_pll_power_enable(dev_priv, pll, enable_reg);
+
+	icl_dpll_write(dev_priv, pll);
+
+	/*
+	 * DVFS pre sequence would be here, but in our driver the cdclk code
+	 * paths should already be setting the appropriate voltage, hence we do
+	 * nothing here.
+	 */
+
 	icl_pll_enable(dev_priv, pll, enable_reg);
+
+	/* DVFS post sequence would be here. See the comment above. */
 }
 
 static void mg_pll_enable(struct drm_i915_private *dev_priv,
@@ -3171,7 +3177,19 @@ static void mg_pll_enable(struct drm_i915_private *dev_priv,
 	i915_reg_t enable_reg =
 		MG_PLL_ENABLE(icl_pll_id_to_tc_port(pll->info->id));
 
+	icl_pll_power_enable(dev_priv, pll, enable_reg);
+
+	icl_mg_pll_write(dev_priv, pll);
+
+	/*
+	 * DVFS pre sequence would be here, but in our driver the cdclk code
+	 * paths should already be setting the appropriate voltage, hence we do
+	 * nothing here.
+	 */
+
 	icl_pll_enable(dev_priv, pll, enable_reg);
+
+	/* DVFS post sequence would be here. See the comment above. */
 }
 
 static void icl_pll_disable(struct drm_i915_private *dev_priv,