drm/connector: Add drm_connector_find_by_fwnode() function (v3)

Add a function to find a connector based on a fwnode.

This will be used by the new drm_connector_oob_hotplug_event()
function which is added by the next patch in this patch-set.

Changes in v2:
- Complete rewrite to use a global connector list in drm_connector.c
  rather then using a class-dev-iter in drm_sysfs.c

Changes in v3:
- Add forward declaration for struct fwnode_handle to drm_crtc_internal.h
  (fixes warning reported by kernel test robot <lkp@intel.com>)

Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-4-hdegoede@redhat.com

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 3ad359a216ff343ead8b00561375b0955325d9d9..7d72bcefa4d6f868b6f36b91fd7c7dae77c3f352 100644 (file)
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -65,6 +65,14 @@
  * support can instead use e.g. drm_helper_hpd_irq_event().
  */
 
+/*
+ * Global connector list for drm_connector_find_by_fwnode().
+ * Note drm_connector_[un]register() first take connector->lock and then
+ * take the connector_list_lock.
+ */
+static DEFINE_MUTEX(connector_list_lock);
+static LIST_HEAD(connector_list);
+
 struct drm_conn_prop_enum_list {
        int type;
        const char *name;
@@ -267,6 +275,7 @@ int drm_connector_init(struct drm_device *dev,
                goto out_put_type_id;
        }
 
+       INIT_LIST_HEAD(&connector->global_connector_list_entry);
        INIT_LIST_HEAD(&connector->probed_modes);
        INIT_LIST_HEAD(&connector->modes);
        mutex_init(&connector->mutex);
@@ -534,6 +543,9 @@ int drm_connector_register(struct drm_connector *connector)
        /* Let userspace know we have a new connector */
        drm_sysfs_hotplug_event(connector->dev);
 
+       mutex_lock(&connector_list_lock);
+       list_add_tail(&connector->global_connector_list_entry, &connector_list);
+       mutex_unlock(&connector_list_lock);
        goto unlock;
 
 err_debugfs:
@@ -562,6 +574,10 @@ void drm_connector_unregister(struct drm_connector *connector)
                return;
        }
 
+       mutex_lock(&connector_list_lock);
+       list_del_init(&connector->global_connector_list_entry);
+       mutex_unlock(&connector_list_lock);
+
        if (connector->funcs->early_unregister)
                connector->funcs->early_unregister(connector);
 
@@ -2545,6 +2561,40 @@ out:
        return ret;
 }
 
+/**
+ * drm_connector_find_by_fwnode - Find a connector based on the associated fwnode
+ * @fwnode: fwnode for which to find the matching drm_connector
+ *
+ * This functions looks up a drm_connector based on its associated fwnode. When
+ * a connector is found a reference to the connector is returned. The caller must
+ * call drm_connector_put() to release this reference when it is done with the
+ * connector.
+ *
+ * Returns: A reference to the found connector or an ERR_PTR().
+ */
+struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
+{
+       struct drm_connector *connector, *found = ERR_PTR(-ENODEV);
+
+       if (!fwnode)
+               return ERR_PTR(-ENODEV);
+
+       mutex_lock(&connector_list_lock);
+
+       list_for_each_entry(connector, &connector_list, global_connector_list_entry) {
+               if (connector->fwnode == fwnode ||
+                   (connector->fwnode && connector->fwnode->secondary == fwnode)) {
+                       drm_connector_get(connector);
+                       found = connector;
+                       break;
+               }
+       }
+
+       mutex_unlock(&connector_list_lock);
+
+       return found;
+}
+
 
 /**
  * DOC: Tile group

diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index edb772947cb4a928896d501e6bf7358343b2ef62..63279e984342cd0f293e7d7e1d4cdc51934c2286 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -58,6 +58,7 @@ struct drm_property;
 struct edid;
 struct kref;
 struct work_struct;
+struct fwnode_handle;
 
 /* drm_crtc.c */
 int drm_mode_crtc_set_obj_prop(struct drm_mode_object *obj,
@@ -186,6 +187,7 @@ int drm_connector_set_obj_prop(struct drm_mode_object *obj,
 int drm_connector_create_standard_properties(struct drm_device *dev);
 const char *drm_get_connector_force_name(enum drm_connector_force force);
 void drm_connector_free_work_fn(struct work_struct *work);
+struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode);
 
 /* IOCTL */
 int drm_connector_property_set_ioctl(struct drm_device *dev,

diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 69dd488a2154e0ba19960abe4caf6dc9611c9502..8132c48b56aeed72be0ef50e60a6e00670dbc747 100644 (file)
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1247,6 +1247,14 @@ struct drm_connector {
         */
        struct list_head head;
 
+       /**
+        * @global_connector_list_entry:
+        *
+        * Connector entry in the global connector-list, used by
+        * drm_connector_find_by_fwnode().
+        */
+       struct list_head global_connector_list_entry;
+
        /** @base: base KMS object */
        struct drm_mode_object base;