drm/i915: Add new helper to return current attached encoder for connector

For introducing splitted encoder/connector structure, this helper will return
connector's attached encoder when needed.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

2 files changed, 26 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 412b442dc941..f9e11e863428 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4983,6 +4983,31 @@ struct drm_encoder *intel_best_encoder(struct drm_connector *connector)
 }
 
 /*
+ * Return which encoder is currently attached for connector.
+ */
+struct drm_encoder *intel_attached_encoder (struct drm_connector *connector)
+{
+        struct drm_mode_object *obj;
+        struct drm_encoder *encoder;
+        int i;
+
+        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+                if (connector->encoder_ids[i] == 0)
+                        break;
+
+                obj = drm_mode_object_find(connector->dev,
+                                           connector->encoder_ids[i],
+                                           DRM_MODE_OBJECT_ENCODER);
+                if (!obj)
+                        continue;
+
+                encoder = obj_to_encoder(obj);
+                return encoder;
+        }
+        return NULL;
+}
+
+/*
  * set vga decode state - true == enable VGA decode
  */
 int intel_modeset_vga_set_state(struct drm_device *dev, bool state)
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index d48c31220e02..5b2e3b219801 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -190,6 +190,7 @@ extern void intel_encoder_prepare (struct drm_encoder *encoder);
 extern void intel_encoder_commit (struct drm_encoder *encoder);
 
 extern struct drm_encoder *intel_best_encoder(struct drm_connector *connector);
+extern struct drm_encoder *intel_attached_encoder(struct drm_connector *connector);
 
 extern struct drm_display_mode *intel_crtc_mode_get(struct drm_device *dev,
                                                     struct drm_crtc *crtc);