drm/i915: Create helper functions to determine eDP power state

We need to check eDP VDD force and panel on in several places, so
create some simple helper functions to avoid duplicating code.

Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -283,20 +283,34 @@ intel_hrawclk(struct drm_device *dev)
 	}
 }
 
+static bool ironlake_edp_have_panel_power(struct intel_dp *intel_dp)
+{
+	struct drm_device *dev = intel_dp->base.base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return (I915_READ(PCH_PP_STATUS) & PP_ON) != 0;
+}
+
+static bool ironlake_edp_have_panel_vdd(struct intel_dp *intel_dp)
+{
+	struct drm_device *dev = intel_dp->base.base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return (I915_READ(PCH_PP_CONTROL) & EDP_FORCE_VDD) != 0;
+}
+
 static void
 intel_dp_check_edp(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp->base.base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 pp_status, pp_control;
+
 	if (!is_edp(intel_dp))
 		return;
-	pp_status = I915_READ(PCH_PP_STATUS);
-	pp_control = I915_READ(PCH_PP_CONTROL);
-	if ((pp_status & PP_ON) == 0 && (pp_control & EDP_FORCE_VDD) == 0) {
+	if (!ironlake_edp_have_panel_power(intel_dp) && !ironlake_edp_have_panel_vdd(intel_dp)) {
 		WARN(1, "eDP powered off while attempting aux channel communication.\n");
 		DRM_DEBUG_KMS("Status 0x%08x Control 0x%08x\n",
-			      pp_status,
+			      I915_READ(PCH_PP_STATUS),
 			      I915_READ(PCH_PP_CONTROL));
 	}
 }
@@ -852,16 +866,11 @@ static void ironlake_edp_panel_vdd_on(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp->base.base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 pp, pp_status;
+	u32 pp;
 
 	if (!is_edp(intel_dp))
 		return;
 	DRM_DEBUG_KMS("Turn eDP VDD on\n");
-	/*
-	 * If the panel wasn't on, make sure there's not a currently
-	 * active PP sequence before enabling AUX VDD.
-	 */
-	pp_status = I915_READ(PCH_PP_STATUS);
 
 	pp = I915_READ(PCH_PP_CONTROL);
 	pp &= ~PANEL_UNLOCK_MASK;
@@ -871,7 +880,11 @@ static void ironlake_edp_panel_vdd_on(struct intel_dp *intel_dp)
 	POSTING_READ(PCH_PP_CONTROL);
 	DRM_DEBUG_KMS("PCH_PP_STATUS: 0x%08x PCH_PP_CONTROL: 0x%08x\n",
 		      I915_READ(PCH_PP_STATUS), I915_READ(PCH_PP_CONTROL));
-	if (!(pp_status & PP_ON)) {
+
+	/*
+	 * If the panel wasn't on, delay before accessing aux channel
+	 */
+	if (!ironlake_edp_have_panel_power(intel_dp)) {
 		msleep(intel_dp->panel_power_up_delay);
 		DRM_DEBUG_KMS("eDP VDD was not on\n");
 	}
@@ -908,7 +921,7 @@ static void ironlake_edp_panel_on (struct intel_dp *intel_dp)
 
 	if (!is_edp(intel_dp))
 		return true;
-	if (I915_READ(PCH_PP_STATUS) & PP_ON)
+	if (ironlake_edp_have_panel_power(intel_dp))
 		return;
 
 	pp = I915_READ(PCH_PP_CONTROL);