drm/atomic: cleanup debugfs entries on un-registering the driver.

Cleanup the debugfs entries created by
commit 6559c901:  drm/atomic: add debugfs file to dump out atomic state
when the driver's minor gets un-registered. Without it, DRM drivers
compiled as modules cannot be rmmod-ed and modprobed again.
Tested-by: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161117114129.2627-1-Liviu.Dudau@arm.com
Fixes: 6559c901 ("drm/atomic: add debugfs file to dump out atomic state")

drivers/gpu/drm/drm_atomic.c

@@ -1686,6 +1686,13 @@ int drm_atomic_debugfs_init(struct drm_minor *minor)
 			ARRAY_SIZE(drm_atomic_debugfs_list),
 			minor->debugfs_root, minor);
 }
+
+int drm_atomic_debugfs_cleanup(struct drm_minor *minor)
+{
+	return drm_debugfs_remove_files(drm_atomic_debugfs_list,
+					ARRAY_SIZE(drm_atomic_debugfs_list),
+					minor);
+}
 #endif
 
 /*

drivers/gpu/drm/drm_debugfs.c

@@ -228,6 +228,7 @@ EXPORT_SYMBOL(drm_debugfs_remove_files);
 int drm_debugfs_cleanup(struct drm_minor *minor)
 {
 	struct drm_device *dev = minor->dev;
+	int ret;
 
 	if (!minor->debugfs_root)
 		return 0;
@@ -235,6 +236,14 @@ int drm_debugfs_cleanup(struct drm_minor *minor)
 	if (dev->driver->debugfs_cleanup)
 		dev->driver->debugfs_cleanup(minor);
 
+	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
+		ret = drm_atomic_debugfs_cleanup(minor);
+		if (ret) {
+			DRM_ERROR("DRM: Failed to remove atomic debugfs entries\n");
+			return ret;
+		}
+	}
+
 	drm_debugfs_remove_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES, minor);
 
 	debugfs_remove(minor->debugfs_root);

include/drm/drm_atomic.h

@@ -372,6 +372,7 @@ void drm_state_dump(struct drm_device *dev, struct drm_printer *p);
 #ifdef CONFIG_DEBUG_FS
 struct drm_minor;
 int drm_atomic_debugfs_init(struct drm_minor *minor);
+int drm_atomic_debugfs_cleanup(struct drm_minor *minor);
 #endif
 
 #define for_each_connector_in_state(__state, connector, connector_state, __i) \