[PATCH 2/4 v2] drm: introduce drm_connector_register_all() helper

[Alexey Brodkin <Alexey.Brodkin@synopsys.com>]

As a pair to already existing drm_connector_unregister_all() we're adding
generic implementation of what is already done in some drivers.

Once this helper is implemented we'll be ready to switch existing
driver-specific implementations with the generic one.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
---

Changes v1 -> v2:
 * Rename drm_connector_unplug_all() to drm_connector_unregister_all()
 * Use drm_for_each_connector() instead of list_for_each_entry()
 * Updated kerneldoc for drm_dev_register()

 drivers/gpu/drm/drm_crtc.c | 50 +++++++++++++++++++++++++++++++++++++++++++---
 drivers/gpu/drm/drm_drv.c  |  6 +++++-
 include/drm/drm_crtc.h     |  3 ++-
 3 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 76453cd..2ad0ce9 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1080,13 +1080,57 @@ void drm_connector_unregister(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_connector_unregister);
 
+/**
+ * drm_connector_register_all - register all connectors
+ * @dev: drm device
+ *
+ * This function just calls drm_connector_register() for all connectors.
+ * Should be called when the device is disconnected, e.g. from an usb driver's
+ * ->connect callback.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_connector_register_all(struct drm_device *dev)
+{
+	struct drm_connector *connector, *failed;
+	int ret;
+
+	mutex_lock(&dev->mode_config.mutex);
+
+	drm_for_each_connector(connector, dev) {
+		ret = drm_connector_register(connector);
+		if (ret) {
+			failed = connector;
+			goto err;
+		}
+	}
+
+
+	mutex_unlock(&dev->mode_config.mutex);
+
+	return 0;
+
+err:
+	drm_for_each_connector(connector, dev) {
+		if (failed == connector)
+			break;
+
+		drm_connector_unregister(connector);
+	}
+
+	mutex_unlock(&dev->mode_config.mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_connector_register_all);
 
 /**
  * drm_connector_unregister_all - unregister connector userspace interfaces
  * @dev: drm device
  *
  * This function unregisters all connector userspace interfaces in sysfs. Should
- * be call when the device is disconnected, e.g. from an usb driver's
+ * be called when the device is disconnected, e.g. from an usb driver's
  * ->disconnect callback.
  */
 void drm_connector_unregister_all(struct drm_device *dev)
@@ -1094,9 +1138,9 @@ void drm_connector_unregister_all(struct drm_device *dev)
 	struct drm_connector *connector;
 
 	/* FIXME: taking the mode config mutex ends up in a clash with sysfs */
-	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
+	drm_for_each_connector(connector, dev) {
 		drm_connector_unregister(connector);
-
+	}
 }
 EXPORT_SYMBOL(drm_connector_unregister_all);
 
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 167c8d3..5580a90 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -715,7 +715,11 @@ EXPORT_SYMBOL(drm_dev_unref);
  *
  * Register the DRM device @dev with the system, advertise device to user-space
  * and start normal device operation. @dev must be allocated via drm_dev_alloc()
- * previously.
+ * previously. Right after drm_dev_register() the driver should call
+ * drm_connector_plug_all() to register all connectors in sysfs. This is
+ * a separate call for backward compatibility with drivers still using
+ * the deprecated ->load() callback, where connectors are registered from within
+ * the ->load() callback.
  *
  * Never call this twice on any device!
  *
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 42d9f4d..6a34117 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -2214,7 +2214,8 @@ void drm_connector_unregister(struct drm_connector *connector);
 
 extern void drm_connector_cleanup(struct drm_connector *connector);
 extern unsigned int drm_connector_index(struct drm_connector *connector);
-/* helper to unregister all connectors from sysfs for device */
+/* helpers to {un}register all connectors from sysfs for device */
+extern int drm_connector_register_all(struct drm_device *dev);
 extern void drm_connector_unregister_all(struct drm_device *dev);
 
 extern int drm_bridge_add(struct drm_bridge *bridge);
-- 
2.5.0