drm/bridge_connector: rely on drm_kms_helper_poll_* for HPD enablement

Use drm_connector's helpers enable_hpd and disable_hpd to enable and
disable HPD automatically by the means of drm_kms_helper_poll_*
functions. As the drm_bridge_connector_enable_hpd() and
drm_bridge_connector_disable_hpd() functions are now unused, replace
them with stubs to ease driver migration.

Enabling the HPD from drm_bridge_connector_init() can happen too early,
before the driver is prepared to handle HPD events. As the
drm_bridge_connector_enable_hpd() is empty anyway, drop this call
anyway.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221102180705.459294-4-dmitry.baryshkov@linaro.org

drivers/gpu/drm/drm_bridge_connector.c

@@ -136,6 +136,11 @@ static void drm_bridge_connector_hpd_cb(void *cb_data,
  * This is typically used by display drivers in their resume handler.
  */
 void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
+{
+}
+EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd);
+
+static void _drm_bridge_connector_enable_hpd(struct drm_connector *connector)
 {
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
@@ -145,7 +150,6 @@ void drm_bridge_connector_enable_hpd(struct drm_connector *connector)
 		drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb,
 				      bridge_connector);
 }
-EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd);
 
 /**
  * drm_bridge_connector_disable_hpd - Disable hot-plug detection for the
@@ -156,6 +160,11 @@ EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd);
  * This is typically used by display drivers in their suspend handler.
  */
 void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
+{
+}
+EXPORT_SYMBOL_GPL(drm_bridge_connector_disable_hpd);
+
+static void _drm_bridge_connector_disable_hpd(struct drm_connector *connector)
 {
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
@@ -164,7 +173,6 @@ void drm_bridge_connector_disable_hpd(struct drm_connector *connector)
 	if (hpd)
 		drm_bridge_hpd_disable(hpd);
 }
-EXPORT_SYMBOL_GPL(drm_bridge_connector_disable_hpd);
 
 /* -----------------------------------------------------------------------------
  * Bridge Connector Functions
@@ -305,6 +313,8 @@ static int drm_bridge_connector_get_modes(struct drm_connector *connector)
 static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = {
 	.get_modes = drm_bridge_connector_get_modes,
 	/* No need for .mode_valid(), the bridges are checked by the core. */
+	.enable_hpd = _drm_bridge_connector_enable_hpd,
+	.disable_hpd = _drm_bridge_connector_disable_hpd,
 };
 
 /* -----------------------------------------------------------------------------
@@ -387,10 +397,8 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 				    connector_type, ddc);
 	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
 
-	if (bridge_connector->bridge_hpd) {
+	if (bridge_connector->bridge_hpd)
 		connector->polled = DRM_CONNECTOR_POLL_HPD;
-		drm_bridge_connector_enable_hpd(connector);
-	}
 	else if (bridge_connector->bridge_detect)
 		connector->polled = DRM_CONNECTOR_POLL_CONNECT
 				  | DRM_CONNECTOR_POLL_DISCONNECT;