[PATCH v2] drm/connector: Add of_drm_find_connector

[Andy Yan <andy.yan@rock-chips.com>]

Add a function to look up a connector by
device tree node, like what of_drm_find_bridge/panel
does.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reported-by: kernel test robot <lkp@intel.com>

---

Changes in v2:
- Add function declaration

 drivers/gpu/drm/drm_connector.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_connector.h     | 14 ++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index d877ddc6dc57..516376cd1868 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -743,6 +743,39 @@ void drm_connector_list_iter_end(struct drm_connector_list_iter *iter)
 }
 EXPORT_SYMBOL(drm_connector_list_iter_end);
 
+#ifdef CONFIG_OF
+/**
+ * of_drm_find_connector - look up a connector using a device tree node
+ * @np: device tree node of the connector
+ *
+ *
+ * Return: A pointer to the connector which match the specified device tree
+ * node or NULL if no panel matching the device tree node can be found, or
+ * -ENODEV: the device is not available (status != "okay" or "ok")
+ */
+struct drm_connector *of_drm_find_connector(struct drm_device *dev, const struct device_node *np)
+{
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+
+	if (!of_device_is_available(np))
+		return ERR_PTR(-ENODEV);
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (connector->of_node == np) {
+			drm_connector_list_iter_end(&conn_iter);
+			return connector;
+		}
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	return NULL;
+}
+EXPORT_SYMBOL(of_drm_find_connector);
+#endif
+
+
 static const struct drm_prop_enum_list drm_subpixel_enum_list[] = {
 	{ SubPixelUnknown, "Unknown" },
 	{ SubPixelHorizontalRGB, "Horizontal RGB" },
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index fd543d1db9b2..d249e0498375 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1129,6 +1129,9 @@ struct drm_connector {
 	/** @attr: sysfs attributes */
 	struct device_attribute *attr;
 
+	/** @of_node: device tree node */
+	struct device_node *of_node;
+
 	/**
 	 * @head:
 	 *
@@ -1647,6 +1650,17 @@ void drm_connector_list_iter_end(struct drm_connector_list_iter *iter);
 bool drm_connector_has_possible_encoder(struct drm_connector *connector,
 					struct drm_encoder *encoder);
 
+#if defined(CONFIG_OF)
+struct drm_connector *
+of_drm_find_connector(struct drm_device *dev, const struct device_node *np);
+#else
+static inline struct drm_connector *
+of_drm_find_connector(struct drm_device *dev, const struct device_node *np)
+{
+	return ERR_PTR(-ENODEV);
+}
+#endif
+
 /**
  * drm_for_each_connector_iter - connector_list iterator macro
  * @connector: &struct drm_connector pointer used as cursor
-- 
2.17.1