[PATCH v2 02/21] drm: Add a callback from connector registering

[Chris Wilson]

If a driver wants to more precisely control its initialisation and in
particular, defer registering its interfaces with userspace until after
everything is setup, it also needs to defer registering the connectors.
As some devices need more work during registration, add a callback so
that drivers can do additional work if required for a connector.

Correspondingly, we also require an unregister callback.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: dri-devel at lists.freedesktop.org
---
 drivers/gpu/drm/drm_crtc.c | 18 ++++++++++++++++--
 include/drm/drm_crtc.h     | 25 +++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index d2a6d958ca76..81641544ac3e 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1036,13 +1036,24 @@ int drm_connector_register(struct drm_connector *connector)
 
 	ret = drm_debugfs_connector_add(connector);
 	if (ret) {
-		drm_sysfs_connector_remove(connector);
-		return ret;
+		goto err_sysfs;
+	}
+
+	if (connector->funcs->late_register) {
+		ret = connector->funcs->late_register(connector);
+		if (ret)
+			goto err_debugfs;
 	}
 
 	drm_mode_object_register(connector->dev, &connector->base);
 
 	return 0;
+
+err_debugfs:
+	drm_debugfs_connector_remove(connector);
+err_sysfs:
+	drm_sysfs_connector_remove(connector);
+	return ret;
 }
 EXPORT_SYMBOL(drm_connector_register);
 
@@ -1054,6 +1065,9 @@ EXPORT_SYMBOL(drm_connector_register);
  */
 void drm_connector_unregister(struct drm_connector *connector)
 {
+	if (connector->funcs->early_unregister)
+		connector->funcs->early_unregister(connector);
+
 	drm_sysfs_connector_remove(connector);
 	drm_debugfs_connector_remove(connector);
 }
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index d1559cd04e3d..77b775cff4e7 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -926,6 +926,31 @@ struct drm_connector_funcs {
 			     uint64_t val);
 
 	/**
+	 * @late_register:
+	 *
+	 * Register the connector with userspace, called from
+	 * drm_connector_register. This should be called after driver
+	 * load during its registration phase. All actions such as registering
+	 * with auxiliary devices (such as drm_dp_aux_register) should be done
+	 * during this callback. A simple guideline is that everything added
+	 * from this callback should be removed during early_unregister (and
+	 * vice versa).
+	 *
+	 */
+	int (*late_register)(struct drm_connector *connector);
+
+	/**
+	 * @early_unregister:
+	 *
+	 * Unregister the connector with userspace, called from
+	 * drm_connector_unregister. This is called early in the driver
+	 * unload sequence to disable userspace access before data
+	 * structures are torndown.  A simple guideline is that this callback
+	 * should remove everything added during late_register (and vice versa).
+	 */
+	void (*early_unregister)(struct drm_connector *connector);
+
+	/**
 	 * @destroy:
 	 *
 	 * Clean up connector resources. This is called at driver unload time
-- 
2.8.1