drm/connector: Share with non-atomic drivers the function to get the single encoder

This 3 non-atomic drivers all have the same function getting the
only encoder available in the connector, also atomic drivers have
this fallback. So moving it a common place and sharing between atomic
and non-atomic drivers.

While at it I also removed the mention of
drm_atomic_helper_best_encoder() that was renamed in
commit 297e30b5d9 ("drm/atomic-helper: Unexport
drm_atomic_helper_best_encoder").

v3: moving drm_connector_get_single_encoder to drm_kms_helper module

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190913232857.389834-1-jose.souza@intel.com

drivers/gpu/drm/ast/ast_mode.c

@@ -687,17 +687,6 @@ static void ast_encoder_destroy(struct drm_encoder *encoder)
 	kfree(encoder);
 }
 
-
-static struct drm_encoder *ast_best_single_encoder(struct drm_connector *connector)
-{
-	int enc_id = connector->encoder_ids[0];
-	/* pick the encoder ids */
-	if (enc_id)
-		return drm_encoder_find(connector->dev, NULL, enc_id);
-	return NULL;
-}
-
-
 static const struct drm_encoder_funcs ast_enc_funcs = {
 	.destroy = ast_encoder_destroy,
 };
@@ -847,7 +836,6 @@ static void ast_connector_destroy(struct drm_connector *connector)
 static const struct drm_connector_helper_funcs ast_connector_helper_funcs = {
 	.mode_valid = ast_mode_valid,
 	.get_modes = ast_get_modes,
-	.best_encoder = ast_best_single_encoder,
 };
 
 static const struct drm_connector_funcs ast_connector_funcs = {

drivers/gpu/drm/drm_atomic_helper.c

@@ -97,17 +97,6 @@ drm_atomic_helper_plane_changed(struct drm_atomic_state *state,
 	}
 }
 
-/*
- * For connectors that support multiple encoders, either the
- * .atomic_best_encoder() or .best_encoder() operation must be implemented.
- */
-static struct drm_encoder *
-pick_single_encoder_for_connector(struct drm_connector *connector)
-{
-	WARN_ON(connector->encoder_ids[1]);
-	return drm_encoder_find(connector->dev, NULL, connector->encoder_ids[0]);
-}
-
 static int handle_conflicting_encoders(struct drm_atomic_state *state,
 				       bool disable_conflicting_encoders)
 {
@@ -135,7 +124,7 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 		else if (funcs->best_encoder)
 			new_encoder = funcs->best_encoder(connector);
 		else
-			new_encoder = pick_single_encoder_for_connector(connector);
+			new_encoder = drm_connector_get_single_encoder(connector);
 
 		if (new_encoder) {
 			if (encoder_mask & drm_encoder_mask(new_encoder)) {
@@ -359,7 +348,7 @@ update_connector_routing(struct drm_atomic_state *state,
 	else if (funcs->best_encoder)
 		new_encoder = funcs->best_encoder(connector);
 	else
-		new_encoder = pick_single_encoder_for_connector(connector);
+		new_encoder = drm_connector_get_single_encoder(connector);
 
 	if (!new_encoder) {
 		DRM_DEBUG_ATOMIC("No suitable encoder found for [CONNECTOR:%d:%s]\n",

drivers/gpu/drm/drm_crtc_helper.c

@@ -481,6 +481,17 @@ drm_crtc_helper_disable(struct drm_crtc *crtc)
 	__drm_helper_disable_unused_functions(dev);
 }
 
+/*
+ * For connectors that support multiple encoders, either the
+ * .atomic_best_encoder() or .best_encoder() operation must be implemented.
+ */
+struct drm_encoder *
+drm_connector_get_single_encoder(struct drm_connector *connector)
+{
+	WARN_ON(connector->encoder_ids[1]);
+	return drm_encoder_find(connector->dev, NULL, connector->encoder_ids[0]);
+}
+
 /**
  * drm_crtc_helper_set_config - set a new config from userspace
  * @set: mode set configuration
@@ -646,7 +657,11 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set,
 		new_encoder = connector->encoder;
 		for (ro = 0; ro < set->num_connectors; ro++) {
 			if (set->connectors[ro] == connector) {
+				if (connector_funcs->best_encoder)
 					new_encoder = connector_funcs->best_encoder(connector);
+				else
+					new_encoder = drm_connector_get_single_encoder(connector);
+
 				/* if we can't get an encoder for a connector
 				   we are setting now - then fail */
 				if (new_encoder == NULL)

drivers/gpu/drm/drm_crtc_helper_internal.h

@@ -75,3 +75,6 @@ enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder,
 					    const struct drm_display_mode *mode);
 enum drm_mode_status drm_connector_mode_valid(struct drm_connector *connector,
 					      struct drm_display_mode *mode);
+
+struct drm_encoder *
+drm_connector_get_single_encoder(struct drm_connector *connector);

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -1638,16 +1638,6 @@ static enum drm_mode_status mga_vga_mode_valid(struct drm_connector *connector,
 	return MODE_OK;
 }
 
-static struct drm_encoder *mga_connector_best_encoder(struct drm_connector
-						  *connector)
-{
-	int enc_id = connector->encoder_ids[0];
-	/* pick the encoder ids */
-	if (enc_id)
-		return drm_encoder_find(connector->dev, NULL, enc_id);
-	return NULL;
-}
-
 static void mga_connector_destroy(struct drm_connector *connector)
 {
 	struct mga_connector *mga_connector = to_mga_connector(connector);
@@ -1659,7 +1649,6 @@ static void mga_connector_destroy(struct drm_connector *connector)
 static const struct drm_connector_helper_funcs mga_vga_connector_helper_funcs = {
 	.get_modes = mga_vga_get_modes,
 	.mode_valid = mga_vga_mode_valid,
-	.best_encoder = mga_connector_best_encoder,
 };
 
 static const struct drm_connector_funcs mga_vga_connector_funcs = {

drivers/gpu/drm/udl/udl_connector.c

@@ -90,13 +90,6 @@ udl_detect(struct drm_connector *connector, bool force)
 	return connector_status_connected;
 }
 
-static struct drm_encoder*
-udl_best_single_encoder(struct drm_connector *connector)
-{
-	int enc_id = connector->encoder_ids[0];
-	return drm_encoder_find(connector->dev, NULL, enc_id);
-}
-
 static int udl_connector_set_property(struct drm_connector *connector,
 				      struct drm_property *property,
 				      uint64_t val)
@@ -120,7 +113,6 @@ static void udl_connector_destroy(struct drm_connector *connector)
 static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
 	.get_modes = udl_get_modes,
 	.mode_valid = udl_mode_valid,
-	.best_encoder = udl_best_single_encoder,
 };
 
 static const struct drm_connector_funcs udl_connector_funcs = {

include/drm/drm_modeset_helper_vtables.h

@@ -955,9 +955,8 @@ struct drm_connector_helper_funcs {
 	 * @atomic_best_encoder.
 	 *
 	 * You can leave this function to NULL if the connector is only
-	 * attached to a single encoder and you are using the atomic helpers.
+	 * attached to a single encoder. In this case, the core will call
-	 * In this case, the core will call drm_atomic_helper_best_encoder()
+	 * drm_connector_get_single_encoder() for you.
-	 * for you.
 	 *
 	 * RETURNS:
 	 *
@@ -977,7 +976,7 @@ struct drm_connector_helper_funcs {
 	 *
 	 * This function is used by drm_atomic_helper_check_modeset().
 	 * If it is not implemented, the core will fallback to @best_encoder
-	 * (or drm_atomic_helper_best_encoder() if @best_encoder is NULL).
+	 * (or drm_connector_get_single_encoder() if @best_encoder is NULL).
 	 *
 	 * NOTE:
 	 *